source: MondoRescue/branches/stable/mindi-busybox/shell/hush.c@ 1770

/* vi: set sw=4 ts=4: */
/*
 * sh.c -- a prototype Bourne shell grammar parser
 *      Intended to follow the original Thompson and Ritchie
 *      "small and simple is beautiful" philosophy, which
 *      incidentally is a good match to today's BusyBox.
 *
 * Copyright (C) 2000,2001  Larry Doolittle  <larry@doolittle.boa.org>
 *
 * Credits:
 *      The parser routines proper are all original material, first
 *      written Dec 2000 and Jan 2001 by Larry Doolittle.  The
 *      execution engine, the builtins, and much of the underlying
 *      support has been adapted from busybox-0.49pre's lash, which is
 *      Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 *      written by Erik Andersen <andersen@codepoet.org>.  That, in turn,
 *      is based in part on ladsh.c, by Michael K. Johnson and Erik W.
 *      Troan, which they placed in the public domain.  I don't know
 *      how much of the Johnson/Troan code has survived the repeated
 *      rewrites.
 *
 * Other credits:
 *      b_addchr() derived from similar w_addchar function in glibc-2.2
 *      setup_redirect(), redirect_opt_num(), and big chunks of main()
 *      and many builtins derived from contributions by Erik Andersen
 *      miscellaneous bugfixes from Matt Kraai
 *
 * There are two big (and related) architecture differences between
 * this parser and the lash parser.  One is that this version is
 * actually designed from the ground up to understand nearly all
 * of the Bourne grammar.  The second, consequential change is that
 * the parser and input reader have been turned inside out.  Now,
 * the parser is in control, and asks for input as needed.  The old
 * way had the input reader in control, and it asked for parsing to
 * take place as needed.  The new way makes it much easier to properly
 * handle the recursion implicit in the various substitutions, especially
 * across continuation lines.
 *
 * Bash grammar not implemented: (how many of these were in original sh?)
 *      $_
 *      ! negation operator for pipes
 *      &> and >& redirection of stdout+stderr
 *      Brace Expansion
 *      Tilde Expansion
 *      fancy forms of Parameter Expansion
 *      aliases
 *      Arithmetic Expansion
 *      <(list) and >(list) Process Substitution
 *      reserved words: case, esac, select, function
 *      Here Documents ( << word )
 *      Functions
 * Major bugs:
 *      job handling woefully incomplete and buggy (improved --vda)
 *      reserved word execution woefully incomplete and buggy
 * to-do:
 *      port selected bugfixes from post-0.49 busybox lash - done?
 *      finish implementing reserved words: for, while, until, do, done
 *      change { and } from special chars to reserved words
 *      builtins: break, continue, eval, return, set, trap, ulimit
 *      test magic exec
 *      handle children going into background
 *      clean up recognition of null pipes
 *      check setting of global_argc and global_argv
 *      control-C handling, probably with longjmp
 *      follow IFS rules more precisely, including update semantics
 *      figure out what to do with backslash-newline
 *      explain why we use signal instead of sigaction
 *      propagate syntax errors, die on resource errors?
 *      continuation lines, both explicit and implicit - done?
 *      memory leak finding and plugging - done?
 *      more testing, especially quoting rules and redirection
 *      document how quoting rules not precisely followed for variable assignments
 *      maybe change charmap[] to use 2-bit entries
 *      (eventually) remove all the printf's
 *
 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
 */


#include <glob.h>      /* glob, of course */
#include <getopt.h>    /* should be pretty obvious */
/* #include <dmalloc.h> */

extern char **environ; /* This is in <unistd.h>, but protected with __USE_GNU */

#include "busybox.h" /* for struct bb_applet */


/* If you comment out one of these below, it will be #defined later
 * to perform debug printfs to stderr: */
#define debug_printf(...)        do {} while (0)
/* Finer-grained debug switches */
#define debug_printf_parse(...)  do {} while (0)
#define debug_print_tree(a, b)   do {} while (0)
#define debug_printf_exec(...)   do {} while (0)
#define debug_printf_jobs(...)   do {} while (0)
#define debug_printf_expand(...) do {} while (0)
#define debug_printf_clean(...)  do {} while (0)

#ifndef debug_printf
#define debug_printf(...) fprintf(stderr, __VA_ARGS__)
#endif

#ifndef debug_printf_parse
#define debug_printf_parse(...) fprintf(stderr, __VA_ARGS__)
#endif

#ifndef debug_printf_exec
#define debug_printf_exec(...) fprintf(stderr, __VA_ARGS__)
#endif

#ifndef debug_printf_jobs
#define debug_printf_jobs(...) fprintf(stderr, __VA_ARGS__)
#define DEBUG_SHELL_JOBS 1
#endif

#ifndef debug_printf_expand
#define debug_printf_expand(...) fprintf(stderr, __VA_ARGS__)
#define DEBUG_EXPAND 1
#endif

/* Keep unconditionally on for now */
#define ENABLE_HUSH_DEBUG 1

#ifndef debug_printf_clean
/* broken, of course, but OK for testing */
static const char *indenter(int i)
{
    static const char blanks[] ALIGN1 =
        "                                    ";
    return &blanks[sizeof(blanks) - i - 1];
}
#define debug_printf_clean(...) fprintf(stderr, __VA_ARGS__)
#define DEBUG_CLEAN 1
#endif


#if !ENABLE_HUSH_INTERACTIVE
#undef ENABLE_FEATURE_EDITING
#define ENABLE_FEATURE_EDITING 0
#undef ENABLE_FEATURE_EDITING_FANCY_PROMPT
#define ENABLE_FEATURE_EDITING_FANCY_PROMPT 0
#endif

#define SPECIAL_VAR_SYMBOL   3

#define PARSEFLAG_EXIT_FROM_LOOP 1
#define PARSEFLAG_SEMICOLON      (1 << 1)  /* symbol ';' is special for parser */
#define PARSEFLAG_REPARSING      (1 << 2)  /* >= 2nd pass */

typedef enum {
    REDIRECT_INPUT     = 1,
    REDIRECT_OVERWRITE = 2,
    REDIRECT_APPEND    = 3,
    REDIRECT_HEREIS    = 4,
    REDIRECT_IO        = 5
} redir_type;

/* The descrip member of this structure is only used to make debugging
 * output pretty */
static const struct {
    int mode;
    signed char default_fd;
    char descrip[3];
} redir_table[] = {
    { 0,                         0, "()" },
    { O_RDONLY,                  0, "<"  },
    { O_CREAT|O_TRUNC|O_WRONLY,  1, ">"  },
    { O_CREAT|O_APPEND|O_WRONLY, 1, ">>" },
    { O_RDONLY,                 -1, "<<" },
    { O_RDWR,                    1, "<>" }
};

typedef enum {
    PIPE_SEQ = 1,
    PIPE_AND = 2,
    PIPE_OR  = 3,
    PIPE_BG  = 4,
} pipe_style;

/* might eventually control execution */
typedef enum {
    RES_NONE  = 0,
#if ENABLE_HUSH_IF
    RES_IF    = 1,
    RES_THEN  = 2,
    RES_ELIF  = 3,
    RES_ELSE  = 4,
    RES_FI    = 5,
#endif
#if ENABLE_HUSH_LOOPS
    RES_FOR   = 6,
    RES_WHILE = 7,
    RES_UNTIL = 8,
    RES_DO    = 9,
    RES_DONE  = 10,
    RES_IN    = 11,
#endif
    RES_XXXX  = 12,
    RES_SNTX  = 13
} reserved_style;
enum {
    FLAG_END   = (1 << RES_NONE ),
#if ENABLE_HUSH_IF
    FLAG_IF    = (1 << RES_IF   ),
    FLAG_THEN  = (1 << RES_THEN ),
    FLAG_ELIF  = (1 << RES_ELIF ),
    FLAG_ELSE  = (1 << RES_ELSE ),
    FLAG_FI    = (1 << RES_FI   ),
#endif
#if ENABLE_HUSH_LOOPS
    FLAG_FOR   = (1 << RES_FOR  ),
    FLAG_WHILE = (1 << RES_WHILE),
    FLAG_UNTIL = (1 << RES_UNTIL),
    FLAG_DO    = (1 << RES_DO   ),
    FLAG_DONE  = (1 << RES_DONE ),
    FLAG_IN    = (1 << RES_IN   ),
#endif
    FLAG_START = (1 << RES_XXXX ),
};

/* This holds pointers to the various results of parsing */
struct p_context {
    struct child_prog *child;
    struct pipe *list_head;
    struct pipe *pipe;
    struct redir_struct *pending_redirect;
    smallint res_w;
    smallint parse_type;        /* bitmask of PARSEFLAG_xxx, defines type of parser : ";$" common or special symbol */
    int old_flag;               /* bitmask of FLAG_xxx, for figuring out valid reserved words */
    struct p_context *stack;
    /* How about quoting status? */
};

struct redir_struct {
    struct redir_struct *next;  /* pointer to the next redirect in the list */
    redir_type type;            /* type of redirection */
    int fd;                     /* file descriptor being redirected */
    int dup;                    /* -1, or file descriptor being duplicated */
    glob_t word;                /* *word.gl_pathv is the filename */
};

struct child_prog {
    pid_t pid;                  /* 0 if exited */
    char **argv;                /* program name and arguments */
    struct pipe *group;         /* if non-NULL, first in group or subshell */
    smallint subshell;          /* flag, non-zero if group must be forked */
    smallint is_stopped;        /* is the program currently running? */
    struct redir_struct *redirects; /* I/O redirections */
    glob_t glob_result;         /* result of parameter globbing */
    struct pipe *family;        /* pointer back to the child's parent pipe */
    //sp counting seems to be broken... so commented out, grep for '//sp:'
    //sp: int sp;               /* number of SPECIAL_VAR_SYMBOL */
    //seems to be unused, grep for '//pt:'
    //pt: int parse_type;
};
/* argv vector may contain variable references (^Cvar^C, ^C0^C etc)
 * and on execution these are substituted with their values.
 * Substitution can make _several_ words out of one argv[n]!
 * Example: argv[0]=='.^C*^C.' here: echo .$*.
 */

struct pipe {
    struct pipe *next;
    int num_progs;              /* total number of programs in job */
    int running_progs;          /* number of programs running (not exited) */
    int stopped_progs;          /* number of programs alive, but stopped */
#if ENABLE_HUSH_JOB
    int jobid;                  /* job number */
    pid_t pgrp;                 /* process group ID for the job */
    char *cmdtext;              /* name of job */
#endif
    char *cmdbuf;               /* buffer various argv's point into */
    struct child_prog *progs;   /* array of commands in pipe */
    int job_context;            /* bitmask defining current context */
    smallint followup;          /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
    smallint res_word;          /* needed for if, for, while, until... */
};

struct close_me {
    struct close_me *next;
    int fd;
};

/* On program start, environ points to initial environment.
 * putenv adds new pointers into it, unsetenv removes them.
 * Neither of these (de)allocates the strings.
 * setenv allocates new strings in malloc space and does putenv,
 * and thus setenv is unusable (leaky) for shell's purposes */
#define setenv(...) setenv_is_leaky_dont_use()
struct variable {
    struct variable *next;
    char *varstr;        /* points to "name=" portion */
    int max_len;         /* if > 0, name is part of initial env; else name is malloced */
    smallint flg_export; /* putenv should be done on this var */
    smallint flg_read_only;
};

typedef struct {
    char *data;
    int length;
    int maxlen;
    int quote;
    int nonnull;
} o_string;
#define NULL_O_STRING {NULL,0,0,0,0}
/* used for initialization: o_string foo = NULL_O_STRING; */

/* I can almost use ordinary FILE *.  Is open_memstream() universally
 * available?  Where is it documented? */
struct in_str {
    const char *p;
    /* eof_flag=1: last char in ->p is really an EOF */
    char eof_flag; /* meaningless if ->p == NULL */
    char peek_buf[2];
#if ENABLE_HUSH_INTERACTIVE
    smallint promptme;
    smallint promptmode; /* 0: PS1, 1: PS2 */
#endif
    FILE *file;
    int (*get) (struct in_str *);
    int (*peek) (struct in_str *);
};
#define b_getch(input) ((input)->get(input))
#define b_peek(input) ((input)->peek(input))

enum {
    CHAR_ORDINARY           = 0,
    CHAR_ORDINARY_IF_QUOTED = 1, /* example: *, # */
    CHAR_IFS                = 2, /* treated as ordinary if quoted */
    CHAR_SPECIAL            = 3, /* example: $ */
};

#define HUSH_VER_STR "0.02"

/* "Globals" within this file */

/* Sorted roughly by size (smaller offsets == smaller code) */
struct globals {
#if ENABLE_HUSH_INTERACTIVE
    /* 'interactive_fd' is a fd# open to ctty, if we have one
     * _AND_ if we decided to act interactively */
    int interactive_fd;
    const char *PS1;
    const char *PS2;
#endif
#if ENABLE_FEATURE_EDITING
    line_input_t *line_input_state;
#endif
#if ENABLE_HUSH_JOB
    int run_list_level;
    pid_t saved_task_pgrp;
    pid_t saved_tty_pgrp;
    int last_jobid;
    struct pipe *job_list;
    struct pipe *toplevel_list;
    smallint ctrl_z_flag;
#endif
    smallint fake_mode;
    /* these three support $?, $#, and $1 */
    char **global_argv;
    int global_argc;
    int last_return_code;
    const char *ifs;
    struct close_me *close_me_head;
    const char *cwd;
    unsigned last_bg_pid;
    struct variable *top_var; /* = &shell_ver (set in main()) */
    struct variable shell_ver;
#if ENABLE_FEATURE_SH_STANDALONE
    struct nofork_save_area nofork_save;
#endif
#if ENABLE_HUSH_JOB
    sigjmp_buf toplevel_jb;
#endif
    unsigned char charmap[256];
    char user_input_buf[ENABLE_FEATURE_EDITING ? BUFSIZ : 2];
};

#define G (*ptr_to_globals)

#if !ENABLE_HUSH_INTERACTIVE
enum { interactive_fd = 0 };
#endif
#if !ENABLE_HUSH_JOB
enum { run_list_level = 0 };
#endif

#if ENABLE_HUSH_INTERACTIVE
#define interactive_fd   (G.interactive_fd  )
#define PS1              (G.PS1             )
#define PS2              (G.PS2             )
#endif
#if ENABLE_FEATURE_EDITING
#define line_input_state (G.line_input_state)
#endif
#if ENABLE_HUSH_JOB
#define run_list_level   (G.run_list_level  )
#define saved_task_pgrp  (G.saved_task_pgrp )
#define saved_tty_pgrp   (G.saved_tty_pgrp  )
#define last_jobid       (G.last_jobid      )
#define job_list         (G.job_list        )
#define toplevel_list    (G.toplevel_list   )
#define toplevel_jb      (G.toplevel_jb     )
#define ctrl_z_flag      (G.ctrl_z_flag     )
#endif /* JOB */
#define global_argv      (G.global_argv     )
#define global_argc      (G.global_argc     )
#define last_return_code (G.last_return_code)
#define ifs              (G.ifs             )
#define fake_mode        (G.fake_mode       )
#define close_me_head    (G.close_me_head   )
#define cwd              (G.cwd             )
#define last_bg_pid      (G.last_bg_pid     )
#define top_var          (G.top_var         )
#define shell_ver        (G.shell_ver       )
#if ENABLE_FEATURE_SH_STANDALONE
#define nofork_save      (G.nofork_save     )
#endif
#if ENABLE_HUSH_JOB
#define toplevel_jb      (G.toplevel_jb     )
#endif
#define charmap          (G.charmap         )
#define user_input_buf   (G.user_input_buf  )


#define B_CHUNK  100
#define B_NOSPAC 1
#define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"

#if 1
/* Normal */
static void syntax(const char *msg)
{
    /* Was using fancy stuff:
     * (interactive_fd ? bb_error_msg : bb_error_msg_and_die)(...params...)
     * but it SEGVs. ?! Oh well... explicit temp ptr works around that */
    void (*fp)(const char *s, ...);

    fp = (interactive_fd ? bb_error_msg : bb_error_msg_and_die);
    fp(msg ? "%s: %s" : "syntax error", "syntax error", msg);
}

#else
/* Debug */
static void syntax_lineno(int line)
{
    void (*fp)(const char *s, ...);

    fp = (interactive_fd ? bb_error_msg : bb_error_msg_and_die);
    fp("syntax error hush.c:%d", line);
}
#define syntax(str) syntax_lineno(__LINE__)
#endif

/* Index of subroutines: */
/*   function prototypes for builtins */
static int builtin_cd(char **argv);
static int builtin_eval(char **argv);
static int builtin_exec(char **argv);
static int builtin_exit(char **argv);
static int builtin_export(char **argv);
#if ENABLE_HUSH_JOB
static int builtin_fg_bg(char **argv);
static int builtin_jobs(char **argv);
#endif
#if ENABLE_HUSH_HELP
static int builtin_help(char **argv);
#endif
static int builtin_pwd(char **argv);
static int builtin_read(char **argv);
static int builtin_set(char **argv);
static int builtin_shift(char **argv);
static int builtin_source(char **argv);
static int builtin_umask(char **argv);
static int builtin_unset(char **argv);
//static int builtin_not_written(char **argv);
/*   o_string manipulation: */
static int b_check_space(o_string *o, int len);
static int b_addchr(o_string *o, int ch);
static void b_reset(o_string *o);
static int b_addqchr(o_string *o, int ch, int quote);
/*  in_str manipulations: */
static int static_get(struct in_str *i);
static int static_peek(struct in_str *i);
static int file_get(struct in_str *i);
static int file_peek(struct in_str *i);
static void setup_file_in_str(struct in_str *i, FILE *f);
static void setup_string_in_str(struct in_str *i, const char *s);
/*  close_me manipulations: */
static void mark_open(int fd);
static void mark_closed(int fd);
static void close_all(void);
/*  "run" the final data structures: */
#if !defined(DEBUG_CLEAN)
#define free_pipe_list(head, indent) free_pipe_list(head)
#define free_pipe(pi, indent)        free_pipe(pi)
#endif
static int free_pipe_list(struct pipe *head, int indent);
static int free_pipe(struct pipe *pi, int indent);
/*  really run the final data structures: */
static int setup_redirects(struct child_prog *prog, int squirrel[]);
static int run_list_real(struct pipe *pi);
static void pseudo_exec_argv(char **argv) ATTRIBUTE_NORETURN;
static void pseudo_exec(struct child_prog *child) ATTRIBUTE_NORETURN;
static int run_pipe_real(struct pipe *pi);
/*   extended glob support: */
static int globhack(const char *src, int flags, glob_t *pglob);
static int glob_needed(const char *s);
static int xglob(o_string *dest, int flags, glob_t *pglob);
/*   variable assignment: */
static int is_assignment(const char *s);
/*   data structure manipulation: */
static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input);
static void initialize_context(struct p_context *ctx);
static int done_word(o_string *dest, struct p_context *ctx);
static int done_command(struct p_context *ctx);
static int done_pipe(struct p_context *ctx, pipe_style type);
/*   primary string parsing: */
static int redirect_dup_num(struct in_str *input);
static int redirect_opt_num(o_string *o);
#if ENABLE_HUSH_TICK
static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, const char *subst_end);
#endif
static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch);
static const char *lookup_param(const char *src);
static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input);
static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, const char *end_trigger);
/*   setup: */
static int parse_and_run_stream(struct in_str *inp, int parse_flag);
static int parse_and_run_string(const char *s, int parse_flag);
static int parse_and_run_file(FILE *f);
/*   job management: */
static int checkjobs(struct pipe* fg_pipe);
#if ENABLE_HUSH_JOB
static int checkjobs_and_fg_shell(struct pipe* fg_pipe);
static void insert_bg_job(struct pipe *pi);
static void remove_bg_job(struct pipe *pi);
static void delete_finished_bg_job(struct pipe *pi);
#else
int checkjobs_and_fg_shell(struct pipe* fg_pipe); /* never called */
#endif
/*     local variable support */
static char **expand_strvec_to_strvec(char **argv);
/* used for eval */
static char *expand_strvec_to_string(char **argv);
/* used for expansion of right hand of assignments */
static char *expand_string_to_string(const char *str);
static struct variable *get_local_var(const char *name);
static int set_local_var(char *str, int flg_export);
static void unset_local_var(const char *name);

/* Table of built-in functions.  They can be forked or not, depending on
 * context: within pipes, they fork.  As simple commands, they do not.
 * When used in non-forking context, they can change global variables
 * in the parent shell process.  If forked, of course they cannot.
 * For example, 'unset foo | whatever' will parse and run, but foo will
 * still be set at the end. */
struct built_in_command {
    const char *cmd;                /* name */
    int (*function) (char **argv);  /* function ptr */
#if ENABLE_HUSH_HELP
    const char *descr;              /* description */
#define BLTIN(cmd, func, help) { cmd, func, help }
#else
#define BLTIN(cmd, func, help) { cmd, func }
#endif
};

static const struct built_in_command bltins[] = {
#if ENABLE_HUSH_JOB
    BLTIN("bg"    , builtin_fg_bg, "Resume a job in the background"),
#endif
//  BLTIN("break" , builtin_not_written, "Exit for, while or until loop"),
    BLTIN("cd"    , builtin_cd, "Change working directory"),
//  BLTIN("continue", builtin_not_written, "Continue for, while or until loop"),
    BLTIN("eval"  , builtin_eval, "Construct and run shell command"),
    BLTIN("exec"  , builtin_exec, "Exec command, replacing this shell with the exec'd process"),
    BLTIN("exit"  , builtin_exit, "Exit from shell"),
    BLTIN("export", builtin_export, "Set environment variable"),
#if ENABLE_HUSH_JOB
    BLTIN("fg"    , builtin_fg_bg, "Bring job into the foreground"),
    BLTIN("jobs"  , builtin_jobs, "Lists the active jobs"),
#endif
// TODO: remove pwd? we have it as an applet...
    BLTIN("pwd"   , builtin_pwd, "Print current directory"),
    BLTIN("read"  , builtin_read, "Input environment variable"),
//  BLTIN("return", builtin_not_written, "Return from a function"),
    BLTIN("set"   , builtin_set, "Set/unset shell local variables"),
    BLTIN("shift" , builtin_shift, "Shift positional parameters"),
//  BLTIN("trap"  , builtin_not_written, "Trap signals"),
//  BLTIN("ulimit", builtin_not_written, "Controls resource limits"),
    BLTIN("umask" , builtin_umask, "Sets file creation mask"),
    BLTIN("unset" , builtin_unset, "Unset environment variable"),
    BLTIN("."     , builtin_source, "Source-in and run commands in a file"),
#if ENABLE_HUSH_HELP
    BLTIN("help"  , builtin_help, "List shell built-in commands"),
#endif
    BLTIN(NULL, NULL, NULL)
};

#if ENABLE_HUSH_JOB

/* move to libbb? */
static void signal_SA_RESTART(int sig, void (*handler)(int))
{
    struct sigaction sa;
    sa.sa_handler = handler;
    sa.sa_flags = SA_RESTART;
    sigemptyset(&sa.sa_mask);
    sigaction(sig, &sa, NULL);
}

/* Signals are grouped, we handle them in batches */
static void set_fatal_sighandler(void (*handler)(int))
{
    signal(SIGILL , handler);
    signal(SIGTRAP, handler);
    signal(SIGABRT, handler);
    signal(SIGFPE , handler);
    signal(SIGBUS , handler);
    signal(SIGSEGV, handler);
    /* bash 3.2 seems to handle these just like 'fatal' ones */
    signal(SIGHUP , handler);
    signal(SIGPIPE, handler);
    signal(SIGALRM, handler);
}
static void set_jobctrl_sighandler(void (*handler)(int))
{
    signal(SIGTSTP, handler);
    signal(SIGTTIN, handler);
    signal(SIGTTOU, handler);
}
static void set_misc_sighandler(void (*handler)(int))
{
    signal(SIGINT , handler);
    signal(SIGQUIT, handler);
    signal(SIGTERM, handler);
}
/* SIGCHLD is special and handled separately */

static void set_every_sighandler(void (*handler)(int))
{
    set_fatal_sighandler(handler);
    set_jobctrl_sighandler(handler);
    set_misc_sighandler(handler);
    signal(SIGCHLD, handler);
}

static void handler_ctrl_c(int sig)
{
    debug_printf_jobs("got sig %d\n", sig);
// as usual we can have all kinds of nasty problems with leaked malloc data here
    siglongjmp(toplevel_jb, 1);
}

static void handler_ctrl_z(int sig)
{
    pid_t pid;

    debug_printf_jobs("got tty sig %d in pid %d\n", sig, getpid());
    pid = fork();
    if (pid < 0) /* can't fork. Pretend there was no ctrl-Z */
        return;
    ctrl_z_flag = 1;
    if (!pid) { /* child */
        setpgrp();
        debug_printf_jobs("set pgrp for child %d ok\n", getpid());
        set_every_sighandler(SIG_DFL);
        raise(SIGTSTP); /* resend TSTP so that child will be stopped */
        debug_printf_jobs("returning in child\n");
        /* return to nofork, it will eventually exit now,
         * not return back to shell */
        return;
    }
    /* parent */
    /* finish filling up pipe info */
    toplevel_list->pgrp = pid; /* child is in its own pgrp */
    toplevel_list->progs[0].pid = pid;
    /* parent needs to longjmp out of running nofork.
     * we will "return" exitcode 0, with child put in background */
// as usual we can have all kinds of nasty problems with leaked malloc data here
    debug_printf_jobs("siglongjmp in parent\n");
    siglongjmp(toplevel_jb, 1);
}

/* Restores tty foreground process group, and exits.
 * May be called as signal handler for fatal signal
 * (will faithfully resend signal to itself, producing correct exit state)
 * or called directly with -EXITCODE.
 * We also call it if xfunc is exiting. */
static void sigexit(int sig) ATTRIBUTE_NORETURN;
static void sigexit(int sig)
{
    sigset_t block_all;

    /* Disable all signals: job control, SIGPIPE, etc. */
    sigfillset(&block_all);
    sigprocmask(SIG_SETMASK, &block_all, NULL);

    if (interactive_fd)
        tcsetpgrp(interactive_fd, saved_tty_pgrp);

    /* Not a signal, just exit */
    if (sig <= 0)
        _exit(- sig);

    /* Enable only this sig and kill ourself with it */
    signal(sig, SIG_DFL);
    sigdelset(&block_all, sig);
    sigprocmask(SIG_SETMASK, &block_all, NULL);
    raise(sig);
    _exit(1); /* Should not reach it */
}

/* Restores tty foreground process group, and exits. */
static void hush_exit(int exitcode) ATTRIBUTE_NORETURN;
static void hush_exit(int exitcode)
{
    fflush(NULL); /* flush all streams */
    sigexit(- (exitcode & 0xff));
}

#else /* !JOB */

#define set_fatal_sighandler(handler)   ((void)0)
#define set_jobctrl_sighandler(handler) ((void)0)
#define set_misc_sighandler(handler)    ((void)0)
#define hush_exit(e)                    exit(e)

#endif /* JOB */


static const char *set_cwd(void)
{
    if (cwd == bb_msg_unknown)
        cwd = NULL;     /* xrealloc_getcwd_or_warn(arg) calls free(arg)! */
    cwd = xrealloc_getcwd_or_warn((char *)cwd);
    if (!cwd)
        cwd = bb_msg_unknown;
    return cwd;
}

/* built-in 'eval' handler */
static int builtin_eval(char **argv)
{
    int rcode = EXIT_SUCCESS;

    if (argv[1]) {
        char *str = expand_strvec_to_string(argv + 1);
        parse_and_run_string(str, PARSEFLAG_EXIT_FROM_LOOP |
                    PARSEFLAG_SEMICOLON);
        free(str);
        rcode = last_return_code;
    }
    return rcode;
}

/* built-in 'cd <path>' handler */
static int builtin_cd(char **argv)
{
    const char *newdir;
    if (argv[1] == NULL)
        newdir = getenv("HOME") ? : "/";
    else
        newdir = argv[1];
    if (chdir(newdir)) {
        printf("cd: %s: %s\n", newdir, strerror(errno));
        return EXIT_FAILURE;
    }
    set_cwd();
    return EXIT_SUCCESS;
}

/* built-in 'exec' handler */
static int builtin_exec(char **argv)
{
    if (argv[1] == NULL)
        return EXIT_SUCCESS;   /* Really? */
    pseudo_exec_argv(argv + 1);
    /* never returns */
}

/* built-in 'exit' handler */
static int builtin_exit(char **argv)
{
// TODO: bash does it ONLY on top-level sh exit (+interacive only?)
    //puts("exit"); /* bash does it */
// TODO: warn if we have background jobs: "There are stopped jobs"
// On second consecutive 'exit', exit anyway.

    if (argv[1] == NULL)
        hush_exit(last_return_code);
    /* mimic bash: exit 123abc == exit 255 + error msg */
    xfunc_error_retval = 255;
    /* bash: exit -2 == exit 254, no error msg */
    hush_exit(xatoi(argv[1]) & 0xff);
}

/* built-in 'export VAR=value' handler */
static int builtin_export(char **argv)
{
    const char *value;
    char *name = argv[1];

    if (name == NULL) {
        // TODO:
        // ash emits: export VAR='VAL'
        // bash: declare -x VAR="VAL"
        // (both also escape as needed (quotes, $, etc))
        char **e = environ;
        if (e)
            while (*e)
                puts(*e++);
        return EXIT_SUCCESS;
    }

    value = strchr(name, '=');
    if (!value) {
        /* They are exporting something without a =VALUE */
        struct variable *var;

        var = get_local_var(name);
        if (var) {
            var->flg_export = 1;
            putenv(var->varstr);
        }
        /* bash does not return an error when trying to export
         * an undefined variable.  Do likewise. */
        return EXIT_SUCCESS;
    }

    set_local_var(xstrdup(name), 1);
    return EXIT_SUCCESS;
}

#if ENABLE_HUSH_JOB
/* built-in 'fg' and 'bg' handler */
static int builtin_fg_bg(char **argv)
{
    int i, jobnum;
    struct pipe *pi;

    if (!interactive_fd)
        return EXIT_FAILURE;
    /* If they gave us no args, assume they want the last backgrounded task */
    if (!argv[1]) {
        for (pi = job_list; pi; pi = pi->next) {
            if (pi->jobid == last_jobid) {
                goto found;
            }
        }
        bb_error_msg("%s: no current job", argv[0]);
        return EXIT_FAILURE;
    }
    if (sscanf(argv[1], "%%%d", &jobnum) != 1) {
        bb_error_msg("%s: bad argument '%s'", argv[0], argv[1]);
        return EXIT_FAILURE;
    }
    for (pi = job_list; pi; pi = pi->next) {
        if (pi->jobid == jobnum) {
            goto found;
        }
    }
    bb_error_msg("%s: %d: no such job", argv[0], jobnum);
    return EXIT_FAILURE;
 found:
    // TODO: bash prints a string representation
    // of job being foregrounded (like "sleep 1 | cat")
    if (*argv[0] == 'f') {
        /* Put the job into the foreground.  */
        tcsetpgrp(interactive_fd, pi->pgrp);
    }

    /* Restart the processes in the job */
    debug_printf_jobs("reviving %d procs, pgrp %d\n", pi->num_progs, pi->pgrp);
    for (i = 0; i < pi->num_progs; i++) {
        debug_printf_jobs("reviving pid %d\n", pi->progs[i].pid);
        pi->progs[i].is_stopped = 0;
    }
    pi->stopped_progs = 0;

    i = kill(- pi->pgrp, SIGCONT);
    if (i < 0) {
        if (errno == ESRCH) {
            delete_finished_bg_job(pi);
            return EXIT_SUCCESS;
        } else {
            bb_perror_msg("kill (SIGCONT)");
        }
    }

    if (*argv[0] == 'f') {
        remove_bg_job(pi);
        return checkjobs_and_fg_shell(pi);
    }
    return EXIT_SUCCESS;
}
#endif

/* built-in 'help' handler */
#if ENABLE_HUSH_HELP
static int builtin_help(char **argv ATTRIBUTE_UNUSED)
{
    const struct built_in_command *x;

    printf("\nBuilt-in commands:\n");
    printf("-------------------\n");
    for (x = bltins; x->cmd; x++) {
        printf("%s\t%s\n", x->cmd, x->descr);
    }
    printf("\n\n");
    return EXIT_SUCCESS;
}
#endif

#if ENABLE_HUSH_JOB
/* built-in 'jobs' handler */
static int builtin_jobs(char **argv ATTRIBUTE_UNUSED)
{
    struct pipe *job;
    const char *status_string;

    for (job = job_list; job; job = job->next) {
        if (job->running_progs == job->stopped_progs)
            status_string = "Stopped";
        else
            status_string = "Running";

        printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->cmdtext);
    }
    return EXIT_SUCCESS;
}
#endif

/* built-in 'pwd' handler */
static int builtin_pwd(char **argv ATTRIBUTE_UNUSED)
{
    puts(set_cwd());
    return EXIT_SUCCESS;
}

/* built-in 'read VAR' handler */
static int builtin_read(char **argv)
{
    char *string;
    const char *name = argv[1] ? argv[1] : "REPLY";

    string = xmalloc_reads(STDIN_FILENO, xasprintf("%s=", name));
    return set_local_var(string, 0);
}

/* built-in 'set [VAR=value]' handler */
static int builtin_set(char **argv)
{
    char *temp = argv[1];
    struct variable *e;

    if (temp == NULL)
        for (e = top_var; e; e = e->next)
            puts(e->varstr);
    else
        set_local_var(xstrdup(temp), 0);

    return EXIT_SUCCESS;
}


/* Built-in 'shift' handler */
static int builtin_shift(char **argv)
{
    int n = 1;
    if (argv[1]) {
        n = atoi(argv[1]);
    }
    if (n >= 0 && n < global_argc) {
        global_argv[n] = global_argv[0];
        global_argc -= n;
        global_argv += n;
        return EXIT_SUCCESS;
    }
    return EXIT_FAILURE;
}

/* Built-in '.' handler (read-in and execute commands from file) */
static int builtin_source(char **argv)
{
    FILE *input;
    int status;

    if (argv[1] == NULL)
        return EXIT_FAILURE;

    /* XXX search through $PATH is missing */
    input = fopen(argv[1], "r");
    if (!input) {
        bb_error_msg("cannot open '%s'", argv[1]);
        return EXIT_FAILURE;
    }

    /* Now run the file */
    /* XXX argv and argc are broken; need to save old global_argv
     * (pointer only is OK!) on this stack frame,
     * set global_argv=argv+1, recurse, and restore. */
    mark_open(fileno(input));
    status = parse_and_run_file(input);
    mark_closed(fileno(input));
    fclose(input);
    return status;
}

static int builtin_umask(char **argv)
{
    mode_t new_umask;
    const char *arg = argv[1];
    char *end;
    if (arg) {
        new_umask = strtoul(arg, &end, 8);
        if (*end != '\0' || end == arg) {
            return EXIT_FAILURE;
        }
    } else {
        new_umask = umask(0);
        printf("%.3o\n", (unsigned) new_umask);
    }
    umask(new_umask);
    return EXIT_SUCCESS;
}

/* built-in 'unset VAR' handler */
static int builtin_unset(char **argv)
{
    /* bash always returns true */
    unset_local_var(argv[1]);
    return EXIT_SUCCESS;
}

//static int builtin_not_written(char **argv)
//{
//  printf("builtin_%s not written\n", argv[0]);
//  return EXIT_FAILURE;
//}

static int b_check_space(o_string *o, int len)
{
    /* It would be easy to drop a more restrictive policy
     * in here, such as setting a maximum string length */
    if (o->length + len > o->maxlen) {
        /* assert(data == NULL || o->maxlen != 0); */
        o->maxlen += (2*len > B_CHUNK ? 2*len : B_CHUNK);
        o->data = xrealloc(o->data, 1 + o->maxlen);
    }
    return o->data == NULL;
}

static int b_addchr(o_string *o, int ch)
{
    debug_printf("b_addchr: '%c' o->length=%d o=%p\n", ch, o->length, o);
    if (b_check_space(o, 1))
        return B_NOSPAC;
    o->data[o->length] = ch;
    o->length++;
    o->data[o->length] = '\0';
    return 0;
}

static void b_reset(o_string *o)
{
    o->length = 0;
    o->nonnull = 0;
    if (o->data != NULL)
        *o->data = '\0';
}

static void b_free(o_string *o)
{
    b_reset(o);
    free(o->data);
    o->data = NULL;
    o->maxlen = 0;
}

/* My analysis of quoting semantics tells me that state information
 * is associated with a destination, not a source.
 */
static int b_addqchr(o_string *o, int ch, int quote)
{
    if (quote && strchr("*?[\\", ch)) {
        int rc;
        rc = b_addchr(o, '\\');
        if (rc)
            return rc;
    }
    return b_addchr(o, ch);
}

static int static_get(struct in_str *i)
{
    int ch = *i->p++;
    if (ch == '\0') return EOF;
    return ch;
}

static int static_peek(struct in_str *i)
{
    return *i->p;
}

#if ENABLE_HUSH_INTERACTIVE
#if ENABLE_FEATURE_EDITING
static void cmdedit_set_initial_prompt(void)
{
#if !ENABLE_FEATURE_EDITING_FANCY_PROMPT
    PS1 = NULL;
#else
    PS1 = getenv("PS1");
    if (PS1 == NULL)
        PS1 = "\\w \\$ ";
#endif
}
#endif /* EDITING */

static const char* setup_prompt_string(int promptmode)
{
    const char *prompt_str;
    debug_printf("setup_prompt_string %d ", promptmode);
#if !ENABLE_FEATURE_EDITING_FANCY_PROMPT
    /* Set up the prompt */
    if (promptmode == 0) { /* PS1 */
        free((char*)PS1);
        PS1 = xasprintf("%s %c ", cwd, (geteuid() != 0) ? '$' : '#');
        prompt_str = PS1;
    } else {
        prompt_str = PS2;
    }
#else
    prompt_str = (promptmode == 0) ? PS1 : PS2;
#endif
    debug_printf("result '%s'\n", prompt_str);
    return prompt_str;
}

static void get_user_input(struct in_str *i)
{
    int r;
    const char *prompt_str;

    prompt_str = setup_prompt_string(i->promptmode);
#if ENABLE_FEATURE_EDITING
    /* Enable command line editing only while a command line
     * is actually being read; otherwise, we'll end up bequeathing
     * atexit() handlers and other unwanted stuff to our
     * child processes (rob@sysgo.de) */
    r = read_line_input(prompt_str, user_input_buf, BUFSIZ-1, line_input_state);
    i->eof_flag = (r < 0);
    if (i->eof_flag) { /* EOF/error detected */
        user_input_buf[0] = EOF; /* yes, it will be truncated, it's ok */
        user_input_buf[1] = '\0';
    }
#else
    fputs(prompt_str, stdout);
    fflush(stdout);
    user_input_buf[0] = r = fgetc(i->file);
    /*user_input_buf[1] = '\0'; - already is and never changed */
    i->eof_flag = (r == EOF);
#endif
    i->p = user_input_buf;
}
#endif  /* INTERACTIVE */

/* This is the magic location that prints prompts
 * and gets data back from the user */
static int file_get(struct in_str *i)
{
    int ch;

    /* If there is data waiting, eat it up */
    if (i->p && *i->p) {
#if ENABLE_HUSH_INTERACTIVE
 take_cached:
#endif
        ch = *i->p++;
        if (i->eof_flag && !*i->p)
            ch = EOF;
    } else {
        /* need to double check i->file because we might be doing something
         * more complicated by now, like sourcing or substituting. */
#if ENABLE_HUSH_INTERACTIVE
        if (interactive_fd && i->promptme && i->file == stdin) {
            do {
                get_user_input(i);
            } while (!*i->p); /* need non-empty line */
            i->promptmode = 1; /* PS2 */
            i->promptme = 0;
            goto take_cached;
        }
#endif
        ch = fgetc(i->file);
    }
    debug_printf("file_get: got a '%c' %d\n", ch, ch);
#if ENABLE_HUSH_INTERACTIVE
    if (ch == '\n')
        i->promptme = 1;
#endif
    return ch;
}

/* All the callers guarantee this routine will never be
 * used right after a newline, so prompting is not needed.
 */
static int file_peek(struct in_str *i)
{
    int ch;
    if (i->p && *i->p) {
        if (i->eof_flag && !i->p[1])
            return EOF;
        return *i->p;
    }
    ch = fgetc(i->file);
    i->eof_flag = (ch == EOF);
    i->peek_buf[0] = ch;
    i->peek_buf[1] = '\0';
    i->p = i->peek_buf;
    debug_printf("file_peek: got a '%c' %d\n", *i->p, *i->p);
    return ch;
}

static void setup_file_in_str(struct in_str *i, FILE *f)
{
    i->peek = file_peek;
    i->get = file_get;
#if ENABLE_HUSH_INTERACTIVE
    i->promptme = 1;
    i->promptmode = 0; /* PS1 */
#endif
    i->file = f;
    i->p = NULL;
}

static void setup_string_in_str(struct in_str *i, const char *s)
{
    i->peek = static_peek;
    i->get = static_get;
#if ENABLE_HUSH_INTERACTIVE
    i->promptme = 1;
    i->promptmode = 0; /* PS1 */
#endif
    i->p = s;
    i->eof_flag = 0;
}

static void mark_open(int fd)
{
    struct close_me *new = xmalloc(sizeof(struct close_me));
    new->fd = fd;
    new->next = close_me_head;
    close_me_head = new;
}

static void mark_closed(int fd)
{
    struct close_me *tmp;
    if (close_me_head == NULL || close_me_head->fd != fd)
        bb_error_msg_and_die("corrupt close_me");
    tmp = close_me_head;
    close_me_head = close_me_head->next;
    free(tmp);
}

static void close_all(void)
{
    struct close_me *c;
    for (c = close_me_head; c; c = c->next) {
        close(c->fd);
    }
    close_me_head = NULL;
}

/* squirrel != NULL means we squirrel away copies of stdin, stdout,
 * and stderr if they are redirected. */
static int setup_redirects(struct child_prog *prog, int squirrel[])
{
    int openfd, mode;
    struct redir_struct *redir;

    for (redir = prog->redirects; redir; redir = redir->next) {
        if (redir->dup == -1 && redir->word.gl_pathv == NULL) {
            /* something went wrong in the parse.  Pretend it didn't happen */
            continue;
        }
        if (redir->dup == -1) {
            mode = redir_table[redir->type].mode;
            openfd = open_or_warn(redir->word.gl_pathv[0], mode);
            if (openfd < 0) {
            /* this could get lost if stderr has been redirected, but
               bash and ash both lose it as well (though zsh doesn't!) */
                return 1;
            }
        } else {
            openfd = redir->dup;
        }

        if (openfd != redir->fd) {
            if (squirrel && redir->fd < 3) {
                squirrel[redir->fd] = dup(redir->fd);
            }
            if (openfd == -3) {
                close(openfd);
            } else {
                dup2(openfd, redir->fd);
                if (redir->dup == -1)
                    close(openfd);
            }
        }
    }
    return 0;
}

static void restore_redirects(int squirrel[])
{
    int i, fd;
    for (i = 0; i < 3; i++) {
        fd = squirrel[i];
        if (fd != -1) {
            /* We simply die on error */
            xmove_fd(fd, i);
        }
    }
}

/* never returns */
/* XXX no exit() here.  If you don't exec, use _exit instead.
 * The at_exit handlers apparently confuse the calling process,
 * in particular stdin handling.  Not sure why? -- because of vfork! (vda) */
static void pseudo_exec_argv(char **argv)
{
    int i, rcode;
    char *p;
    const struct built_in_command *x;

    for (i = 0; is_assignment(argv[i]); i++) {
        debug_printf_exec("pid %d environment modification: %s\n",
                getpid(), argv[i]);
// FIXME: vfork case??
        p = expand_string_to_string(argv[i]);
        putenv(p);
    }
    argv += i;
    /* If a variable is assigned in a forest, and nobody listens,
     * was it ever really set?
     */
    if (argv[0] == NULL) {
        _exit(EXIT_SUCCESS);
    }

    argv = expand_strvec_to_strvec(argv);

    /*
     * Check if the command matches any of the builtins.
     * Depending on context, this might be redundant.  But it's
     * easier to waste a few CPU cycles than it is to figure out
     * if this is one of those cases.
     */
    for (x = bltins; x->cmd; x++) {
        if (strcmp(argv[0], x->cmd) == 0) {
            debug_printf_exec("running builtin '%s'\n", argv[0]);
            rcode = x->function(argv);
            fflush(stdout);
            _exit(rcode);
        }
    }

    /* Check if the command matches any busybox applets */
#if ENABLE_FEATURE_SH_STANDALONE
    if (strchr(argv[0], '/') == NULL) {
        const struct bb_applet *a = find_applet_by_name(argv[0]);
        if (a) {
            if (a->noexec) {
                current_applet = a;
                debug_printf_exec("running applet '%s'\n", argv[0]);
// is it ok that run_current_applet_and_exit() does exit(), not _exit()?
                run_current_applet_and_exit(argv);
            }
            /* re-exec ourselves with the new arguments */
            debug_printf_exec("re-execing applet '%s'\n", argv[0]);
            execvp(bb_busybox_exec_path, argv);
            /* If they called chroot or otherwise made the binary no longer
             * executable, fall through */
        }
    }
#endif

    debug_printf_exec("execing '%s'\n", argv[0]);
    execvp(argv[0], argv);
    bb_perror_msg("cannot exec '%s'", argv[0]);
    _exit(1);
}

static void pseudo_exec(struct child_prog *child)
{
// FIXME: buggy wrt NOMMU! Must not modify any global data
// until it does exec/_exit, but currently it does.
    int rcode;

    if (child->argv) {
        pseudo_exec_argv(child->argv);
    }

    if (child->group) {
    // FIXME: do not modify globals! Think vfork!
#if ENABLE_HUSH_INTERACTIVE
        debug_printf_exec("pseudo_exec: setting interactive_fd=0\n");
        interactive_fd = 0;    /* crucial!!!! */
#endif
        debug_printf_exec("pseudo_exec: run_list_real\n");
        rcode = run_list_real(child->group);
        /* OK to leak memory by not calling free_pipe_list,
         * since this process is about to exit */
        _exit(rcode);
    }

    /* Can happen.  See what bash does with ">foo" by itself. */
    debug_printf("trying to pseudo_exec null command\n");
    _exit(EXIT_SUCCESS);
}

#if ENABLE_HUSH_JOB
static const char *get_cmdtext(struct pipe *pi)
{
    char **argv;
    char *p;
    int len;

    /* This is subtle. ->cmdtext is created only on first backgrounding.
     * (Think "cat, <ctrl-z>, fg, <ctrl-z>, fg, <ctrl-z>...." here...)
     * On subsequent bg argv is trashed, but we won't use it */
    if (pi->cmdtext)
        return pi->cmdtext;
    argv = pi->progs[0].argv;
    if (!argv || !argv[0])
        return (pi->cmdtext = xzalloc(1));

    len = 0;
    do len += strlen(*argv) + 1; while (*++argv);
    pi->cmdtext = p = xmalloc(len);
    argv = pi->progs[0].argv;
    do {
        len = strlen(*argv);
        memcpy(p, *argv, len);
        p += len;
        *p++ = ' ';
    } while (*++argv);
    p[-1] = '\0';
    return pi->cmdtext;
}

static void insert_bg_job(struct pipe *pi)
{
    struct pipe *thejob;
    int i;

    /* Linear search for the ID of the job to use */
    pi->jobid = 1;
    for (thejob = job_list; thejob; thejob = thejob->next)
        if (thejob->jobid >= pi->jobid)
            pi->jobid = thejob->jobid + 1;

    /* Add thejob to the list of running jobs */
    if (!job_list) {
        thejob = job_list = xmalloc(sizeof(*thejob));
    } else {
        for (thejob = job_list; thejob->next; thejob = thejob->next)
            continue;
        thejob->next = xmalloc(sizeof(*thejob));
        thejob = thejob->next;
    }

    /* Physically copy the struct job */
    memcpy(thejob, pi, sizeof(struct pipe));
    thejob->progs = xzalloc(sizeof(pi->progs[0]) * pi->num_progs);
    /* We cannot copy entire pi->progs[] vector! Double free()s will happen */
    for (i = 0; i < pi->num_progs; i++) {
// TODO: do we really need to have so many fields which are just dead weight
// at execution stage?
        thejob->progs[i].pid = pi->progs[i].pid;
        /* all other fields are not used and stay zero */
    }
    thejob->next = NULL;
    thejob->cmdtext = xstrdup(get_cmdtext(pi));

    /* We don't wait for background thejobs to return -- append it
       to the list of backgrounded thejobs and leave it alone */
    printf("[%d] %d %s\n", thejob->jobid, thejob->progs[0].pid, thejob->cmdtext);
    last_bg_pid = thejob->progs[0].pid;
    last_jobid = thejob->jobid;
}

static void remove_bg_job(struct pipe *pi)
{
    struct pipe *prev_pipe;

    if (pi == job_list) {
        job_list = pi->next;
    } else {
        prev_pipe = job_list;
        while (prev_pipe->next != pi)
            prev_pipe = prev_pipe->next;
        prev_pipe->next = pi->next;
    }
    if (job_list)
        last_jobid = job_list->jobid;
    else
        last_jobid = 0;
}

/* remove a backgrounded job */
static void delete_finished_bg_job(struct pipe *pi)
{
    remove_bg_job(pi);
    pi->stopped_progs = 0;
    free_pipe(pi, 0);
    free(pi);
}
#endif /* JOB */

/* Checks to see if any processes have exited -- if they
   have, figure out why and see if a job has completed */
static int checkjobs(struct pipe* fg_pipe)
{
    int attributes;
    int status;
#if ENABLE_HUSH_JOB
    int prognum = 0;
    struct pipe *pi;
#endif
    pid_t childpid;
    int rcode = 0;

    attributes = WUNTRACED;
    if (fg_pipe == NULL) {
        attributes |= WNOHANG;
    }

/* Do we do this right?
 * bash-3.00# sleep 20 | false
 * <ctrl-Z pressed>
 * [3]+  Stopped          sleep 20 | false
 * bash-3.00# echo $?
 * 1   <========== bg pipe is not fully done, but exitcode is already known!
 */

//FIXME: non-interactive bash does not continue even if all processes in fg pipe
//are stopped. Testcase: "cat | cat" in a script (not on command line)
// + killall -STOP cat

 wait_more:
    while ((childpid = waitpid(-1, &status, attributes)) > 0) {
        const int dead = WIFEXITED(status) || WIFSIGNALED(status);

#ifdef DEBUG_SHELL_JOBS
        if (WIFSTOPPED(status))
            debug_printf_jobs("pid %d stopped by sig %d (exitcode %d)\n",
                    childpid, WSTOPSIG(status), WEXITSTATUS(status));
        if (WIFSIGNALED(status))
            debug_printf_jobs("pid %d killed by sig %d (exitcode %d)\n",
                    childpid, WTERMSIG(status), WEXITSTATUS(status));
        if (WIFEXITED(status))
            debug_printf_jobs("pid %d exited, exitcode %d\n",
                    childpid, WEXITSTATUS(status));
#endif
        /* Were we asked to wait for fg pipe? */
        if (fg_pipe) {
            int i;
            for (i = 0; i < fg_pipe->num_progs; i++) {
                debug_printf_jobs("check pid %d\n", fg_pipe->progs[i].pid);
                if (fg_pipe->progs[i].pid == childpid) {
                    /* printf("process %d exit %d\n", i, WEXITSTATUS(status)); */
                    if (dead) {
                        fg_pipe->progs[i].pid = 0;
                        fg_pipe->running_progs--;
                        if (i == fg_pipe->num_progs-1)
                            /* last process gives overall exitstatus */
                            rcode = WEXITSTATUS(status);
                    } else {
                        fg_pipe->progs[i].is_stopped = 1;
                        fg_pipe->stopped_progs++;
                    }
                    debug_printf_jobs("fg_pipe: running_progs %d stopped_progs %d\n",
                            fg_pipe->running_progs, fg_pipe->stopped_progs);
                    if (fg_pipe->running_progs - fg_pipe->stopped_progs <= 0) {
                        /* All processes in fg pipe have exited/stopped */
#if ENABLE_HUSH_JOB
                        if (fg_pipe->running_progs)
                            insert_bg_job(fg_pipe);
#endif
                        return rcode;
                    }
                    /* There are still running processes in the fg pipe */
                    goto wait_more;
                }
            }
            /* fall through to searching process in bg pipes */
        }

#if ENABLE_HUSH_JOB
        /* We asked to wait for bg or orphaned children */
        /* No need to remember exitcode in this case */
        for (pi = job_list; pi; pi = pi->next) {
            prognum = 0;
            while (prognum < pi->num_progs) {
                if (pi->progs[prognum].pid == childpid)
                    goto found_pi_and_prognum;
                prognum++;
            }
        }
#endif

        /* Happens when shell is used as init process (init=/bin/sh) */
        debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
        goto wait_more;

#if ENABLE_HUSH_JOB
 found_pi_and_prognum:
        if (dead) {
            /* child exited */
            pi->progs[prognum].pid = 0;
            pi->running_progs--;
            if (!pi->running_progs) {
                printf(JOB_STATUS_FORMAT, pi->jobid,
                            "Done", pi->cmdtext);
                delete_finished_bg_job(pi);
            }
        } else {
            /* child stopped */
            pi->stopped_progs++;
            pi->progs[prognum].is_stopped = 1;
        }
#endif
    }

    /* wait found no children or failed */

    if (childpid && errno != ECHILD)
        bb_perror_msg("waitpid");
    return rcode;
}

#if ENABLE_HUSH_JOB
static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
{
    pid_t p;
    int rcode = checkjobs(fg_pipe);
    /* Job finished, move the shell to the foreground */
    p = getpgid(0); /* pgid of our process */
    debug_printf_jobs("fg'ing ourself: getpgid(0)=%d\n", (int)p);
    if (tcsetpgrp(interactive_fd, p) && errno != ENOTTY)
        bb_perror_msg("tcsetpgrp-4a");
    return rcode;
}
#endif

/* run_pipe_real() starts all the jobs, but doesn't wait for anything
 * to finish.  See checkjobs().
 *
 * return code is normally -1, when the caller has to wait for children
 * to finish to determine the exit status of the pipe.  If the pipe
 * is a simple builtin command, however, the action is done by the
 * time run_pipe_real returns, and the exit code is provided as the
 * return value.
 *
 * The input of the pipe is always stdin, the output is always
 * stdout.  The outpipe[] mechanism in BusyBox-0.48 lash is bogus,
 * because it tries to avoid running the command substitution in
 * subshell, when that is in fact necessary.  The subshell process
 * now has its stdout directed to the input of the appropriate pipe,
 * so this routine is noticeably simpler.
 *
 * Returns -1 only if started some children. IOW: we have to
 * mask out retvals of builtins etc with 0xff!
 */
static int run_pipe_real(struct pipe *pi)
{
    int i;
    int nextin, nextout;
    int pipefds[2];             /* pipefds[0] is for reading */
    struct child_prog *child;
    const struct built_in_command *x;
    char *p;
    /* it is not always needed, but we aim to smaller code */
    int squirrel[] = { -1, -1, -1 };
    int rcode;
    const int single_fg = (pi->num_progs == 1 && pi->followup != PIPE_BG);

    debug_printf_exec("run_pipe_real start: single_fg=%d\n", single_fg);

    nextin = 0;
#if ENABLE_HUSH_JOB
    pi->pgrp = -1;
#endif
    pi->running_progs = 1;
    pi->stopped_progs = 0;

    /* Check if this is a simple builtin (not part of a pipe).
     * Builtins within pipes have to fork anyway, and are handled in
     * pseudo_exec.  "echo foo | read bar" doesn't work on bash, either.
     */
    child = &(pi->progs[0]);
    if (single_fg && child->group && child->subshell == 0) {
        debug_printf("non-subshell grouping\n");
        setup_redirects(child, squirrel);
        debug_printf_exec(": run_list_real\n");
        rcode = run_list_real(child->group);
        restore_redirects(squirrel);
        debug_printf_exec("run_pipe_real return %d\n", rcode);
        return rcode; // do we need to add '... & 0xff' ?
    }

    if (single_fg && child->argv != NULL) {
        char **argv_expanded;
        char **argv = child->argv;

        for (i = 0; is_assignment(argv[i]); i++)
            continue;
        if (i != 0 && argv[i] == NULL) {
            /* assignments, but no command: set the local environment */
            for (i = 0; argv[i] != NULL; i++) {
                debug_printf("local environment set: %s\n", argv[i]);
                p = expand_string_to_string(argv[i]);
                set_local_var(p, 0);
            }
            return EXIT_SUCCESS;   /* don't worry about errors in set_local_var() yet */
        }
        for (i = 0; is_assignment(argv[i]); i++) {
            p = expand_string_to_string(argv[i]);
            //sp: child->sp--;
            putenv(p);
        }
        for (x = bltins; x->cmd; x++) {
            if (strcmp(argv[i], x->cmd) == 0) {
                if (x->function == builtin_exec && argv[i+1] == NULL) {
                    debug_printf("magic exec\n");
                    setup_redirects(child, NULL);
                    return EXIT_SUCCESS;
                }
                debug_printf("builtin inline %s\n", argv[0]);
                /* XXX setup_redirects acts on file descriptors, not FILEs.
                 * This is perfect for work that comes after exec().
                 * Is it really safe for inline use?  Experimentally,
                 * things seem to work with glibc. */
                setup_redirects(child, squirrel);
                debug_printf_exec(": builtin '%s' '%s'...\n", x->cmd, argv[i+1]);
                //sp: if (child->sp) /* btw we can do it unconditionally... */
                argv_expanded = expand_strvec_to_strvec(argv + i);
                rcode = x->function(argv_expanded) & 0xff;
                free(argv_expanded);
                restore_redirects(squirrel);
                debug_printf_exec("run_pipe_real return %d\n", rcode);
                return rcode;
            }
        }
#if ENABLE_FEATURE_SH_STANDALONE
        {
            const struct bb_applet *a = find_applet_by_name(argv[i]);
            if (a && a->nofork) {
                setup_redirects(child, squirrel);
                save_nofork_data(&nofork_save);
                argv_expanded = argv + i;
                //sp: if (child->sp)
                argv_expanded = expand_strvec_to_strvec(argv + i);
                debug_printf_exec(": run_nofork_applet '%s' '%s'...\n", argv_expanded[0], argv_expanded[1]);
                rcode = run_nofork_applet_prime(&nofork_save, a, argv_expanded) & 0xff;
                free(argv_expanded);
                restore_redirects(squirrel);
                debug_printf_exec("run_pipe_real return %d\n", rcode);
                return rcode;
            }
        }
#endif
    }

    /* Going to fork a child per each pipe member */
    pi->running_progs = 0;

    /* Disable job control signals for shell (parent) and
     * for initial child code after fork */
    set_jobctrl_sighandler(SIG_IGN);

    for (i = 0; i < pi->num_progs; i++) {
        child = &(pi->progs[i]);
        if (child->argv)
            debug_printf_exec(": pipe member '%s' '%s'...\n", child->argv[0], child->argv[1]);
        else
            debug_printf_exec(": pipe member with no argv\n");

        /* pipes are inserted between pairs of commands */
        if ((i + 1) < pi->num_progs) {
            pipe(pipefds);
            nextout = pipefds[1];
        } else {
            nextout = 1;
            pipefds[0] = -1;
        }

        /* XXX test for failed fork()? */
#if BB_MMU
        child->pid = fork();
#else
        child->pid = vfork();
#endif
        if (!child->pid) { /* child */
            /* Every child adds itself to new process group
             * with pgid == pid of first child in pipe */
#if ENABLE_HUSH_JOB
            if (run_list_level == 1 && interactive_fd) {
                /* Don't do pgrp restore anymore on fatal signals */
                set_fatal_sighandler(SIG_DFL);
                if (pi->pgrp < 0) /* true for 1st process only */
                    pi->pgrp = getpid();
                if (setpgid(0, pi->pgrp) == 0 && pi->followup != PIPE_BG) {
                    /* We do it in *every* child, not just first,
                     * to avoid races */
                    tcsetpgrp(interactive_fd, pi->pgrp);
                }
            }
#endif
            /* in non-interactive case fatal sigs are already SIG_DFL */
            close_all();
            if (nextin != 0) {
                dup2(nextin, 0);
                close(nextin);
            }
            if (nextout != 1) {
                dup2(nextout, 1);
                close(nextout);
            }
            if (pipefds[0] != -1) {
                close(pipefds[0]);  /* opposite end of our output pipe */
            }
            /* Like bash, explicit redirects override pipes,
             * and the pipe fd is available for dup'ing. */
            setup_redirects(child, NULL);

            /* Restore default handlers just prior to exec */
            set_jobctrl_sighandler(SIG_DFL);
            set_misc_sighandler(SIG_DFL);
            signal(SIGCHLD, SIG_DFL);
            pseudo_exec(child);
        }

        pi->running_progs++;

#if ENABLE_HUSH_JOB
        /* Second and next children need to know pid of first one */
        if (pi->pgrp < 0)
            pi->pgrp = child->pid;
#endif
        if (nextin != 0)
            close(nextin);
        if (nextout != 1)
            close(nextout);

        /* If there isn't another process, nextin is garbage
           but it doesn't matter */
        nextin = pipefds[0];
    }
    debug_printf_exec("run_pipe_real return -1\n");
    return -1;
}

#ifndef debug_print_tree
static void debug_print_tree(struct pipe *pi, int lvl)
{
    static const char *PIPE[] = {
        [PIPE_SEQ] = "SEQ",
        [PIPE_AND] = "AND",
        [PIPE_OR ] = "OR" ,
        [PIPE_BG ] = "BG" ,
    };
    static const char *RES[] = {
        [RES_NONE ] = "NONE" ,
#if ENABLE_HUSH_IF
        [RES_IF   ] = "IF"   ,
        [RES_THEN ] = "THEN" ,
        [RES_ELIF ] = "ELIF" ,
        [RES_ELSE ] = "ELSE" ,
        [RES_FI   ] = "FI"   ,
#endif
#if ENABLE_HUSH_LOOPS
        [RES_FOR  ] = "FOR"  ,
        [RES_WHILE] = "WHILE",
        [RES_UNTIL] = "UNTIL",
        [RES_DO   ] = "DO"   ,
        [RES_DONE ] = "DONE" ,
        [RES_IN   ] = "IN"   ,
#endif
        [RES_XXXX ] = "XXXX" ,
        [RES_SNTX ] = "SNTX" ,
    };

    int pin, prn;

    pin = 0;
    while (pi) {
        fprintf(stderr, "%*spipe %d res_word=%s followup=%d %s\n", lvl*2, "",
                pin, RES[pi->res_word], pi->followup, PIPE[pi->followup]);
        prn = 0;
        while (prn < pi->num_progs) {
            struct child_prog *child = &pi->progs[prn];
            char **argv = child->argv;

            fprintf(stderr, "%*s prog %d", lvl*2, "", prn);
            if (child->group) {
                fprintf(stderr, " group %s: (argv=%p)\n",
                        (child->subshell ? "()" : "{}"),
                        argv);
                debug_print_tree(child->group, lvl+1);
                prn++;
                continue;
            }
            if (argv) while (*argv) {
                fprintf(stderr, " '%s'", *argv);
                argv++;
            }
            fprintf(stderr, "\n");
            prn++;
        }
        pi = pi->next;
        pin++;
    }
}
#endif

/* NB: called by pseudo_exec, and therefore must not modify any
 * global data until exec/_exit (we can be a child after vfork!) */
static int run_list_real(struct pipe *pi)
{
    struct pipe *rpipe;
#if ENABLE_HUSH_LOOPS
    char *for_varname = NULL;
    char **for_lcur = NULL;
    char **for_list = NULL;
    int flag_rep = 0;
#endif
    int save_num_progs;
    int flag_skip = 1;
    int rcode = 0; /* probably for gcc only */
    int flag_restore = 0;
#if ENABLE_HUSH_IF
    int if_code = 0, next_if_code = 0;  /* need double-buffer to handle elif */
#else
    enum { if_code = 0, next_if_code = 0 };
#endif
    reserved_style rword;
    reserved_style skip_more_for_this_rword = RES_XXXX;

    debug_printf_exec("run_list_real start lvl %d\n", run_list_level + 1);

#if ENABLE_HUSH_LOOPS
    /* check syntax for "for" */
    for (rpipe = pi; rpipe; rpipe = rpipe->next) {
        if ((rpipe->res_word == RES_IN || rpipe->res_word == RES_FOR)
         && (rpipe->next == NULL)
        ) {
            syntax("malformed for"); /* no IN or no commands after IN */
            debug_printf_exec("run_list_real lvl %d return 1\n", run_list_level);
            return 1;
        }
        if ((rpipe->res_word == RES_IN && rpipe->next->res_word == RES_IN && rpipe->next->progs[0].argv != NULL)
         || (rpipe->res_word == RES_FOR && rpipe->next->res_word != RES_IN)
        ) {
            /* TODO: what is tested in the first condition? */
            syntax("malformed for"); /* 2nd condition: not followed by IN */
            debug_printf_exec("run_list_real lvl %d return 1\n", run_list_level);
            return 1;
        }
    }
#else
    rpipe = NULL;
#endif

#if ENABLE_HUSH_JOB
    /* Example of nested list: "while true; do { sleep 1 | exit 2; } done".
     * We are saving state before entering outermost list ("while...done")
     * so that ctrl-Z will correctly background _entire_ outermost list,
     * not just a part of it (like "sleep 1 | exit 2") */
    if (++run_list_level == 1 && interactive_fd) {
        if (sigsetjmp(toplevel_jb, 1)) {
            /* ctrl-Z forked and we are parent; or ctrl-C.
             * Sighandler has longjmped us here */
            signal(SIGINT, SIG_IGN);
            signal(SIGTSTP, SIG_IGN);
            /* Restore level (we can be coming from deep inside
             * nested levels) */
            run_list_level = 1;
#if ENABLE_FEATURE_SH_STANDALONE
            if (nofork_save.saved) { /* if save area is valid */
                debug_printf_jobs("exiting nofork early\n");
                restore_nofork_data(&nofork_save);
            }
#endif
            if (ctrl_z_flag) {
                /* ctrl-Z has forked and stored pid of the child in pi->pid.
                 * Remember this child as background job */
                insert_bg_job(pi);
            } else {
                /* ctrl-C. We just stop doing whatever we were doing */
                putchar('\n');
            }
            rcode = 0;
            goto ret;
        }
        /* ctrl-Z handler will store pid etc in pi */
        toplevel_list = pi;
        ctrl_z_flag = 0;
#if ENABLE_FEATURE_SH_STANDALONE
        nofork_save.saved = 0; /* in case we will run a nofork later */
#endif
        signal_SA_RESTART(SIGTSTP, handler_ctrl_z);
        signal(SIGINT, handler_ctrl_c);
    }
#endif

    for (; pi; pi = flag_restore ? rpipe : pi->next) {
        rword = pi->res_word;
#if ENABLE_HUSH_LOOPS
        if (rword == RES_WHILE || rword == RES_UNTIL || rword == RES_FOR) {
            flag_restore = 0;
            if (!rpipe) {
                flag_rep = 0;
                rpipe = pi;
            }
        }
#endif
        debug_printf_exec(": rword=%d if_code=%d next_if_code=%d skip_more=%d\n",
                rword, if_code, next_if_code, skip_more_for_this_rword);
        if (rword == skip_more_for_this_rword && flag_skip) {
            if (pi->followup == PIPE_SEQ)
                flag_skip = 0;
            continue;
        }
        flag_skip = 1;
        skip_more_for_this_rword = RES_XXXX;
#if ENABLE_HUSH_IF
        if (rword == RES_THEN || rword == RES_ELSE)
            if_code = next_if_code;
        if (rword == RES_THEN && if_code)
            continue;
        if (rword == RES_ELSE && !if_code)
            continue;
        if (rword == RES_ELIF && !if_code)
            break;
#endif
#if ENABLE_HUSH_LOOPS
        if (rword == RES_FOR && pi->num_progs) {
            if (!for_lcur) {
                /* if no variable values after "in" we skip "for" */
                if (!pi->next->progs->argv)
                    continue;
                /* create list of variable values */
                for_list = expand_strvec_to_strvec(pi->next->progs->argv);
                for_lcur = for_list;
                for_varname = pi->progs->argv[0];
                pi->progs->argv[0] = NULL;
                flag_rep = 1;
            }
            free(pi->progs->argv[0]);
            if (!*for_lcur) {
                free(for_list);
                for_lcur = NULL;
                flag_rep = 0;
                pi->progs->argv[0] = for_varname;
                pi->progs->glob_result.gl_pathv[0] = pi->progs->argv[0];
                continue;
            }
            /* insert next value from for_lcur */
            /* vda: does it need escaping? */
            pi->progs->argv[0] = xasprintf("%s=%s", for_varname, *for_lcur++);
            pi->progs->glob_result.gl_pathv[0] = pi->progs->argv[0];
        }
        if (rword == RES_IN)
            continue;
        if (rword == RES_DO) {
            if (!flag_rep)
                continue;
        }
        if (rword == RES_DONE) {
            if (flag_rep) {
                flag_restore = 1;
            } else {
                rpipe = NULL;
            }
        }
#endif
        if (pi->num_progs == 0)
            continue;
        save_num_progs = pi->num_progs; /* save number of programs */
        debug_printf_exec(": run_pipe_real with %d members\n", pi->num_progs);
        rcode = run_pipe_real(pi);
        if (rcode != -1) {
            /* We only ran a builtin: rcode was set by the return value
             * of run_pipe_real(), and we don't need to wait for anything. */
        } else if (pi->followup == PIPE_BG) {
            /* What does bash do with attempts to background builtins? */
            /* Even bash 3.2 doesn't do that well with nested bg:
             * try "{ { sleep 10; echo DEEP; } & echo HERE; } &".
             * I'm NOT treating inner &'s as jobs */
#if ENABLE_HUSH_JOB
            if (run_list_level == 1)
                insert_bg_job(pi);
#endif
            rcode = EXIT_SUCCESS;
        } else {
#if ENABLE_HUSH_JOB
            /* Paranoia, just "interactive_fd" should be enough? */
            if (run_list_level == 1 && interactive_fd) {
                /* waits for completion, then fg's main shell */
                rcode = checkjobs_and_fg_shell(pi);
            } else
#endif
            {
                /* this one just waits for completion */
                rcode = checkjobs(pi);
            }
            debug_printf_exec(": checkjobs returned %d\n", rcode);
        }
        debug_printf_exec(": setting last_return_code=%d\n", rcode);
        last_return_code = rcode;
        pi->num_progs = save_num_progs; /* restore number of programs */
#if ENABLE_HUSH_IF
        if (rword == RES_IF || rword == RES_ELIF)
            next_if_code = rcode;  /* can be overwritten a number of times */
#endif
#if ENABLE_HUSH_LOOPS
        if (rword == RES_WHILE)
            flag_rep = !last_return_code;
        if (rword == RES_UNTIL)
            flag_rep = last_return_code;
#endif
        if ((rcode == EXIT_SUCCESS && pi->followup == PIPE_OR)
         || (rcode != EXIT_SUCCESS && pi->followup == PIPE_AND)
        ) {
            skip_more_for_this_rword = rword;
        }
        checkjobs(NULL);
    }

#if ENABLE_HUSH_JOB
    if (ctrl_z_flag) {
        /* ctrl-Z forked somewhere in the past, we are the child,
         * and now we completed running the list. Exit. */
        exit(rcode);
    }
 ret:
    if (!--run_list_level && interactive_fd) {
        signal(SIGTSTP, SIG_IGN);
        signal(SIGINT, SIG_IGN);
    }
#endif
    debug_printf_exec("run_list_real lvl %d return %d\n", run_list_level + 1, rcode);
    return rcode;
}

/* return code is the exit status of the pipe */
static int free_pipe(struct pipe *pi, int indent)
{
    char **p;
    struct child_prog *child;
    struct redir_struct *r, *rnext;
    int a, i, ret_code = 0;

    if (pi->stopped_progs > 0)
        return ret_code;
    debug_printf_clean("%s run pipe: (pid %d)\n", indenter(indent), getpid());
    for (i = 0; i < pi->num_progs; i++) {
        child = &pi->progs[i];
        debug_printf_clean("%s  command %d:\n", indenter(indent), i);
        if (child->argv) {
            for (a = 0, p = child->argv; *p; a++, p++) {
                debug_printf_clean("%s   argv[%d] = %s\n", indenter(indent), a, *p);
            }
            globfree(&child->glob_result);
            child->argv = NULL;
        } else if (child->group) {
            debug_printf_clean("%s   begin group (subshell:%d)\n", indenter(indent), child->subshell);
            ret_code = free_pipe_list(child->group, indent+3);
            debug_printf_clean("%s   end group\n", indenter(indent));
        } else {
            debug_printf_clean("%s   (nil)\n", indenter(indent));
        }
        for (r = child->redirects; r; r = rnext) {
            debug_printf_clean("%s   redirect %d%s", indenter(indent), r->fd, redir_table[r->type].descrip);
            if (r->dup == -1) {
                /* guard against the case >$FOO, where foo is unset or blank */
                if (r->word.gl_pathv) {
                    debug_printf_clean(" %s\n", *r->word.gl_pathv);
                    globfree(&r->word);
                }
            } else {
                debug_printf_clean("&%d\n", r->dup);
            }
            rnext = r->next;
            free(r);
        }
        child->redirects = NULL;
    }
    free(pi->progs);   /* children are an array, they get freed all at once */
    pi->progs = NULL;
#if ENABLE_HUSH_JOB
    free(pi->cmdtext);
    pi->cmdtext = NULL;
#endif
    return ret_code;
}

static int free_pipe_list(struct pipe *head, int indent)
{
    int rcode = 0;   /* if list has no members */
    struct pipe *pi, *next;

    for (pi = head; pi; pi = next) {
        debug_printf_clean("%s pipe reserved mode %d\n", indenter(indent), pi->res_word);
        rcode = free_pipe(pi, indent);
        debug_printf_clean("%s pipe followup code %d\n", indenter(indent), pi->followup);
        next = pi->next;
        /*pi->next = NULL;*/
        free(pi);
    }
    return rcode;
}

/* Select which version we will use */
static int run_list(struct pipe *pi)
{
    int rcode = 0;
    debug_printf_exec("run_list entered\n");
    if (fake_mode == 0) {
        debug_printf_exec(": run_list_real with %d members\n", pi->num_progs);
        rcode = run_list_real(pi);
    }
    /* free_pipe_list has the side effect of clearing memory.
     * In the long run that function can be merged with run_list_real,
     * but doing that now would hobble the debugging effort. */
    free_pipe_list(pi, 0);
    debug_printf_exec("run_list return %d\n", rcode);
    return rcode;
}

/* The API for glob is arguably broken.  This routine pushes a non-matching
 * string into the output structure, removing non-backslashed backslashes.
 * If someone can prove me wrong, by performing this function within the
 * original glob(3) api, feel free to rewrite this routine into oblivion.
 * Return code (0 vs. GLOB_NOSPACE) matches glob(3).
 * XXX broken if the last character is '\\', check that before calling.
 */
static int globhack(const char *src, int flags, glob_t *pglob)
{
    int cnt = 0, pathc;
    const char *s;
    char *dest;
    for (cnt = 1, s = src; s && *s; s++) {
        if (*s == '\\') s++;
        cnt++;
    }
    dest = xmalloc(cnt);
    if (!(flags & GLOB_APPEND)) {
        pglob->gl_pathv = NULL;
        pglob->gl_pathc = 0;
        pglob->gl_offs = 0;
        pglob->gl_offs = 0;
    }
    pathc = ++pglob->gl_pathc;
    pglob->gl_pathv = xrealloc(pglob->gl_pathv, (pathc+1) * sizeof(*pglob->gl_pathv));
    pglob->gl_pathv[pathc-1] = dest;
    pglob->gl_pathv[pathc] = NULL;
    for (s = src; s && *s; s++, dest++) {
        if (*s == '\\') s++;
        *dest = *s;
    }
    *dest = '\0';
    return 0;
}

/* XXX broken if the last character is '\\', check that before calling */
static int glob_needed(const char *s)
{
    for (; *s; s++) {
        if (*s == '\\') s++;
        if (strchr("*[?", *s)) return 1;
    }
    return 0;
}

static int xglob(o_string *dest, int flags, glob_t *pglob)
{
    int gr;

    /* short-circuit for null word */
    /* we can code this better when the debug_printf's are gone */
    if (dest->length == 0) {
        if (dest->nonnull) {
            /* bash man page calls this an "explicit" null */
            gr = globhack(dest->data, flags, pglob);
            debug_printf("globhack returned %d\n", gr);
        } else {
            return 0;
        }
    } else if (glob_needed(dest->data)) {
        gr = glob(dest->data, flags, NULL, pglob);
        debug_printf("glob returned %d\n", gr);
        if (gr == GLOB_NOMATCH) {
            /* quote removal, or more accurately, backslash removal */
            gr = globhack(dest->data, flags, pglob);
            debug_printf("globhack returned %d\n", gr);
        }
    } else {
        gr = globhack(dest->data, flags, pglob);
        debug_printf("globhack returned %d\n", gr);
    }
    if (gr == GLOB_NOSPACE)
        bb_error_msg_and_die("out of memory during glob");
    if (gr != 0) { /* GLOB_ABORTED ? */
        bb_error_msg("glob(3) error %d", gr);
    }
    /* globprint(glob_target); */
    return gr;
}

/* expand_strvec_to_strvec() takes a list of strings, expands
 * all variable references within and returns a pointer to
 * a list of expanded strings, possibly with larger number
 * of strings. (Think VAR="a b"; echo $VAR).
 * This new list is allocated as a single malloc block.
 * NULL-terminated list of char* pointers is at the beginning of it,
 * followed by strings themself.
 * Caller can deallocate entire list by single free(list). */

/* Helpers first:
 * count_XXX estimates size of the block we need. It's okay
 * to over-estimate sizes a bit, if it makes code simpler */
static int count_ifs(const char *str)
{
    int cnt = 0;
    debug_printf_expand("count_ifs('%s') ifs='%s'", str, ifs);
    while (1) {
        str += strcspn(str, ifs);
        if (!*str) break;
        str++; /* str += strspn(str, ifs); */
        cnt++; /* cnt += strspn(str, ifs); - but this code is larger */
    }
    debug_printf_expand(" return %d\n", cnt);
    return cnt;
}

static void count_var_expansion_space(int *countp, int *lenp, char *arg)
{
    char first_ch;
    int i;
    int len = *lenp;
    int count = *countp;
    const char *val;
    char *p;

    while ((p = strchr(arg, SPECIAL_VAR_SYMBOL))) {
        len += p - arg;
        arg = ++p;
        p = strchr(p, SPECIAL_VAR_SYMBOL);
        first_ch = arg[0];

        switch (first_ch & 0x7f) {
        /* high bit in 1st_ch indicates that var is double-quoted */
        case '$': /* pid */
        case '!': /* bg pid */
        case '?': /* exitcode */
        case '#': /* argc */
            len += sizeof(int)*3 + 1; /* enough for int */
            break;
        case '*':
        case '@':
            for (i = 1; i < global_argc; i++) {
                len += strlen(global_argv[i]) + 1;
                count++;
                if (!(first_ch & 0x80))
                    count += count_ifs(global_argv[i]);
            }
            break;
        default:
            *p = '\0';
            arg[0] = first_ch & 0x7f;
            if (isdigit(arg[0])) {
                i = xatoi_u(arg);
                val = NULL;
                if (i < global_argc)
                    val = global_argv[i];
            } else
                val = lookup_param(arg);
            arg[0] = first_ch;
            *p = SPECIAL_VAR_SYMBOL;

            if (val) {
                len += strlen(val) + 1;
                if (!(first_ch & 0x80))
                    count += count_ifs(val);
            }
        }
        arg = ++p;
    }

    len += strlen(arg) + 1;
    count++;
    *lenp = len;
    *countp = count;
}

/* Store given string, finalizing the word and starting new one whenever
 * we encounter ifs char(s). This is used for expanding variable values.
 * End-of-string does NOT finalize word: think about 'echo -$VAR-' */
static int expand_on_ifs(char **list, int n, char **posp, const char *str)
{
    char *pos = *posp;
    while (1) {
        int word_len = strcspn(str, ifs);
        if (word_len) {
            memcpy(pos, str, word_len); /* store non-ifs chars */
            pos += word_len;
            str += word_len;
        }
        if (!*str)  /* EOL - do not finalize word */
            break;
        *pos++ = '\0';
        if (n) debug_printf_expand("expand_on_ifs finalized list[%d]=%p '%s' "
            "strlen=%d next=%p pos=%p\n", n-1, list[n-1], list[n-1],
            strlen(list[n-1]), list[n-1] + strlen(list[n-1]) + 1, pos);
        list[n++] = pos;
        str += strspn(str, ifs); /* skip ifs chars */
    }
    *posp = pos;
    return n;
}

/* Expand all variable references in given string, adding words to list[]
 * at n, n+1,... positions. Return updated n (so that list[n] is next one
 * to be filled). This routine is extremely tricky: has to deal with
 * variables/parameters with whitespace, $* and $@, and constructs like
 * 'echo -$*-'. If you play here, you must run testsuite afterwards! */
/* NB: another bug is that we cannot detect empty strings yet:
 * "" or $empty"" expands to zero words, has to expand to empty word */
static int expand_vars_to_list(char **list, int n, char **posp, char *arg, char or_mask)
{
    /* or_mask is either 0 (normal case) or 0x80
     * (expansion of right-hand side of assignment == 1-element expand) */

    char first_ch, ored_ch;
    int i;
    const char *val;
    char *p;
    char *pos = *posp;

    ored_ch = 0;

    if (n) debug_printf_expand("expand_vars_to_list finalized list[%d]=%p '%s' "
        "strlen=%d next=%p pos=%p\n", n-1, list[n-1], list[n-1],
        strlen(list[n-1]), list[n-1] + strlen(list[n-1]) + 1, pos);
    list[n++] = pos;

    while ((p = strchr(arg, SPECIAL_VAR_SYMBOL))) {
        memcpy(pos, arg, p - arg);
        pos += (p - arg);
        arg = ++p;
        p = strchr(p, SPECIAL_VAR_SYMBOL);

        first_ch = arg[0] | or_mask; /* forced to "quoted" if or_mask = 0x80 */
        ored_ch |= first_ch;
        val = NULL;
        switch (first_ch & 0x7f) {
        /* Highest bit in first_ch indicates that var is double-quoted */
        case '$': /* pid */
            /* FIXME: (echo $$) should still print pid of main shell */
            val = utoa(getpid());
            break;
        case '!': /* bg pid */
            val = last_bg_pid ? utoa(last_bg_pid) : (char*)"";
            break;
        case '?': /* exitcode */
            val = utoa(last_return_code);
            break;
        case '#': /* argc */
            val = utoa(global_argc ? global_argc-1 : 0);
            break;
        case '*':
        case '@':
            i = 1;
            if (!(first_ch & 0x80)) { /* unquoted $* or $@ */
                while (i < global_argc) {
                    n = expand_on_ifs(list, n, &pos, global_argv[i]);
                    debug_printf_expand("expand_vars_to_list: argv %d (last %d)\n", i, global_argc-1);
                    if (global_argv[i++][0] && i < global_argc) {
                        /* this argv[] is not empty and not last:
                         * put terminating NUL, start new word */
                        *pos++ = '\0';
                        if (n) debug_printf_expand("expand_vars_to_list 2 finalized list[%d]=%p '%s' "
                            "strlen=%d next=%p pos=%p\n", n-1, list[n-1], list[n-1],
                            strlen(list[n-1]), list[n-1] + strlen(list[n-1]) + 1, pos);
                        list[n++] = pos;
                    }
                }
            } else
            /* If or_mask is nonzero, we handle assignment 'a=....$@.....'
             * and in this case should theat it like '$*' */
            if (first_ch == ('@'|0x80) && !or_mask) { /* quoted $@ */
                while (1) {
                    strcpy(pos, global_argv[i]);
                    pos += strlen(global_argv[i]);
                    if (++i >= global_argc)
                        break;
                    *pos++ = '\0';
                    if (n) debug_printf_expand("expand_vars_to_list 3 finalized list[%d]=%p '%s' "
                        "strlen=%d next=%p pos=%p\n", n-1, list[n-1], list[n-1],
                            strlen(list[n-1]), list[n-1] + strlen(list[n-1]) + 1, pos);
                    list[n++] = pos;
                }
            } else { /* quoted $*: add as one word */
                while (1) {
                    strcpy(pos, global_argv[i]);
                    pos += strlen(global_argv[i]);
                    if (++i >= global_argc)
                        break;
                    if (ifs[0])
                        *pos++ = ifs[0];
                }
            }
            break;
        default:
            *p = '\0';
            arg[0] = first_ch & 0x7f;
            if (isdigit(arg[0])) {
                i = xatoi_u(arg);
                val = NULL;
                if (i < global_argc)
                    val = global_argv[i];
            } else
                val = lookup_param(arg);
            arg[0] = first_ch;
            *p = SPECIAL_VAR_SYMBOL;
            if (!(first_ch & 0x80)) { /* unquoted $VAR */
                if (val) {
                    n = expand_on_ifs(list, n, &pos, val);
                    val = NULL;
                }
            } /* else: quoted $VAR, val will be appended at pos */
        }
        if (val) {
            strcpy(pos, val);
            pos += strlen(val);
        }
        arg = ++p;
    }
    debug_printf_expand("expand_vars_to_list adding tail '%s' at %p\n", arg, pos);
    strcpy(pos, arg);
    pos += strlen(arg) + 1;
    if (pos == list[n-1] + 1) { /* expansion is empty */
        if (!(ored_ch & 0x80)) { /* all vars were not quoted... */
            debug_printf_expand("expand_vars_to_list list[%d] empty, going back\n", n);
            pos--;
            n--;
        }
    }

    *posp = pos;
    return n;
}

static char **expand_variables(char **argv, char or_mask)
{
    int n;
    int count = 1;
    int len = 0;
    char *pos, **v, **list;

    v = argv;
    if (!*v) debug_printf_expand("count_var_expansion_space: "
            "argv[0]=NULL count=%d len=%d alloc_space=%d\n",
            count, len, sizeof(char*) * count + len);
    while (*v) {
        count_var_expansion_space(&count, &len, *v);
        debug_printf_expand("count_var_expansion_space: "
            "'%s' count=%d len=%d alloc_space=%d\n",
            *v, count, len, sizeof(char*) * count + len);
        v++;
    }
    len += sizeof(char*) * count; /* total to alloc */
    list = xmalloc(len);
    pos = (char*)(list + count);
    debug_printf_expand("list=%p, list[0] should be %p\n", list, pos);
    n = 0;
    v = argv;
    while (*v)
        n = expand_vars_to_list(list, n, &pos, *v++, or_mask);

    if (n) debug_printf_expand("finalized list[%d]=%p '%s' "
        "strlen=%d next=%p pos=%p\n", n-1, list[n-1], list[n-1],
        strlen(list[n-1]), list[n-1] + strlen(list[n-1]) + 1, pos);
    list[n] = NULL;

#ifdef DEBUG_EXPAND
    {
        int m = 0;
        while (m <= n) {
            debug_printf_expand("list[%d]=%p '%s'\n", m, list[m], list[m]);
            m++;
        }
        debug_printf_expand("used_space=%d\n", pos - (char*)list);
    }
#endif
    if (ENABLE_HUSH_DEBUG)
        if (pos - (char*)list > len)
            bb_error_msg_and_die("BUG in varexp");
    return list;
}

static char **expand_strvec_to_strvec(char **argv)
{
    return expand_variables(argv, 0);
}

static char *expand_string_to_string(const char *str)
{
    char *argv[2], **list;

    argv[0] = (char*)str;
    argv[1] = NULL;
    list = expand_variables(argv, 0x80); /* 0x80: make one-element expansion */
    if (ENABLE_HUSH_DEBUG)
        if (!list[0] || list[1])
            bb_error_msg_and_die("BUG in varexp2");
    /* actually, just move string 2*sizeof(char*) bytes back */
    strcpy((char*)list, list[0]);
    debug_printf_expand("string_to_string='%s'\n", (char*)list);
    return (char*)list;
}

static char* expand_strvec_to_string(char **argv)
{
    char **list;

    list = expand_variables(argv, 0x80);
    /* Convert all NULs to spaces */
    if (list[0]) {
        int n = 1;
        while (list[n]) {
            if (ENABLE_HUSH_DEBUG)
                if (list[n-1] + strlen(list[n-1]) + 1 != list[n])
                    bb_error_msg_and_die("BUG in varexp3");
            list[n][-1] = ' '; /* TODO: or to ifs[0]? */
            n++;
        }
    }
    strcpy((char*)list, list[0]);
    debug_printf_expand("strvec_to_string='%s'\n", (char*)list);
    return (char*)list;
}

/* This is used to get/check local shell variables */
static struct variable *get_local_var(const char *name)
{
    struct variable *cur;
    int len;

    if (!name)
        return NULL;
    len = strlen(name);
    for (cur = top_var; cur; cur = cur->next) {
        if (strncmp(cur->varstr, name, len) == 0 && cur->varstr[len] == '=')
            return cur;
    }
    return NULL;
}

/* str holds "NAME=VAL" and is expected to be malloced.
 * We take ownership of it. */
static int set_local_var(char *str, int flg_export)
{
    struct variable *cur;
    char *value;
    int name_len;

    value = strchr(str, '=');
    if (!value) { /* not expected to ever happen? */
        free(str);
        return -1;
    }

    name_len = value - str + 1; /* including '=' */
    cur = top_var; /* cannot be NULL (we have HUSH_VERSION and it's RO) */
    while (1) {
        if (strncmp(cur->varstr, str, name_len) != 0) {
            if (!cur->next) {
                /* Bail out. Note that now cur points
                 * to last var in linked list */
                break;
            }
            cur = cur->next;
            continue;
        }
        /* We found an existing var with this name */
        *value = '\0';
        if (cur->flg_read_only) {
            bb_error_msg("%s: readonly variable", str);
            free(str);
            return -1;
        }
        unsetenv(str); /* just in case */
        *value = '=';
        if (strcmp(cur->varstr, str) == 0) {
 free_and_exp:
            free(str);
            goto exp;
        }
        if (cur->max_len >= strlen(str)) {
            /* This one is from startup env, reuse space */
            strcpy(cur->varstr, str);
            goto free_and_exp;
        }
        /* max_len == 0 signifies "malloced" var, which we can
         * (and has to) free */
        if (!cur->max_len)
            free(cur->varstr);
        cur->max_len = 0;
        goto set_str_and_exp;
    }

    /* Not found - create next variable struct */
    cur->next = xzalloc(sizeof(*cur));
    cur = cur->next;

 set_str_and_exp:
    cur->varstr = str;
 exp:
    if (flg_export)
        cur->flg_export = 1;
    if (cur->flg_export)
        return putenv(cur->varstr);
    return 0;
}

static void unset_local_var(const char *name)
{
    struct variable *cur;
    struct variable *prev = prev; /* for gcc */
    int name_len;

    if (!name)
        return;
    name_len = strlen(name);
    cur = top_var;
    while (cur) {
        if (strncmp(cur->varstr, name, name_len) == 0 && cur->varstr[name_len] == '=') {
            if (cur->flg_read_only) {
                bb_error_msg("%s: readonly variable", name);
                return;
            }
        /* prev is ok to use here because 1st variable, HUSH_VERSION,
         * is ro, and we cannot reach this code on the 1st pass */
            prev->next = cur->next;
            unsetenv(cur->varstr);
            if (!cur->max_len)
                free(cur->varstr);
            free(cur);
            return;
        }
        prev = cur;
        cur = cur->next;
    }
}

static int is_assignment(const char *s)
{
    if (!s || !isalpha(*s))
        return 0;
    s++;
    while (isalnum(*s) || *s == '_')
        s++;
    return *s == '=';
}

/* the src parameter allows us to peek forward to a possible &n syntax
 * for file descriptor duplication, e.g., "2>&1".
 * Return code is 0 normally, 1 if a syntax error is detected in src.
 * Resource errors (in xmalloc) cause the process to exit */
static int setup_redirect(struct p_context *ctx, int fd, redir_type style,
    struct in_str *input)
{
    struct child_prog *child = ctx->child;
    struct redir_struct *redir = child->redirects;
    struct redir_struct *last_redir = NULL;

    /* Create a new redir_struct and drop it onto the end of the linked list */
    while (redir) {
        last_redir = redir;
        redir = redir->next;
    }
    redir = xmalloc(sizeof(struct redir_struct));
    redir->next = NULL;
    redir->word.gl_pathv = NULL;
    if (last_redir) {
        last_redir->next = redir;
    } else {
        child->redirects = redir;
    }

    redir->type = style;
    redir->fd = (fd == -1) ? redir_table[style].default_fd : fd;

    debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);

    /* Check for a '2>&1' type redirect */
    redir->dup = redirect_dup_num(input);
    if (redir->dup == -2) return 1;  /* syntax error */
    if (redir->dup != -1) {
        /* Erik had a check here that the file descriptor in question
         * is legit; I postpone that to "run time"
         * A "-" representation of "close me" shows up as a -3 here */
        debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
    } else {
        /* We do _not_ try to open the file that src points to,
         * since we need to return and let src be expanded first.
         * Set ctx->pending_redirect, so we know what to do at the
         * end of the next parsed word. */
        ctx->pending_redirect = redir;
    }
    return 0;
}

static struct pipe *new_pipe(void)
{
    struct pipe *pi;
    pi = xzalloc(sizeof(struct pipe));
    /*pi->num_progs = 0;*/
    /*pi->progs = NULL;*/
    /*pi->next = NULL;*/
    /*pi->followup = 0;  invalid */
    if (RES_NONE)
        pi->res_word = RES_NONE;
    return pi;
}

static void initialize_context(struct p_context *ctx)
{
    ctx->child = NULL;
    ctx->pipe = ctx->list_head = new_pipe();
    ctx->pending_redirect = NULL;
    ctx->res_w = RES_NONE;
    //only ctx->parse_type is not touched... is this intentional?
    ctx->old_flag = 0;
    ctx->stack = NULL;
    done_command(ctx);   /* creates the memory for working child */
}

/* normal return is 0
 * if a reserved word is found, and processed, return 1
 * should handle if, then, elif, else, fi, for, while, until, do, done.
 * case, function, and select are obnoxious, save those for later.
 */
#if ENABLE_HUSH_IF || ENABLE_HUSH_LOOPS
static int reserved_word(o_string *dest, struct p_context *ctx)
{
    struct reserved_combo {
        char literal[7];
        unsigned char code;
        int flag;
    };
    /* Mostly a list of accepted follow-up reserved words.
     * FLAG_END means we are done with the sequence, and are ready
     * to turn the compound list into a command.
     * FLAG_START means the word must start a new compound list.
     */
    static const struct reserved_combo reserved_list[] = {
#if ENABLE_HUSH_IF
        { "if",    RES_IF,    FLAG_THEN | FLAG_START },
        { "then",  RES_THEN,  FLAG_ELIF | FLAG_ELSE | FLAG_FI },
        { "elif",  RES_ELIF,  FLAG_THEN },
        { "else",  RES_ELSE,  FLAG_FI   },
        { "fi",    RES_FI,    FLAG_END  },
#endif
#if ENABLE_HUSH_LOOPS
        { "for",   RES_FOR,   FLAG_IN   | FLAG_START },
        { "while", RES_WHILE, FLAG_DO   | FLAG_START },
        { "until", RES_UNTIL, FLAG_DO   | FLAG_START },
        { "in",    RES_IN,    FLAG_DO   },
        { "do",    RES_DO,    FLAG_DONE },
        { "done",  RES_DONE,  FLAG_END  }
#endif
    };

    const struct reserved_combo *r;

    for (r = reserved_list; r < reserved_list + ARRAY_SIZE(reserved_list); r++) {
        if (strcmp(dest->data, r->literal) != 0)
            continue;
        debug_printf("found reserved word %s, code %d\n", r->literal, r->code);
        if (r->flag & FLAG_START) {
            struct p_context *new;
            debug_printf("push stack\n");
#if ENABLE_HUSH_LOOPS
            if (ctx->res_w == RES_IN || ctx->res_w == RES_FOR) {
                syntax("malformed for"); /* example: 'for if' */
                ctx->res_w = RES_SNTX;
                b_reset(dest);
                return 1;
            }
#endif
            new = xmalloc(sizeof(*new));
            *new = *ctx;   /* physical copy */
            initialize_context(ctx);
            ctx->stack = new;
        } else if (ctx->res_w == RES_NONE || !(ctx->old_flag & (1 << r->code))) {
            syntax(NULL);
            ctx->res_w = RES_SNTX;
            b_reset(dest);
            return 1;
        }
        ctx->res_w = r->code;
        ctx->old_flag = r->flag;
        if (ctx->old_flag & FLAG_END) {
            struct p_context *old;
            debug_printf("pop stack\n");
            done_pipe(ctx, PIPE_SEQ);
            old = ctx->stack;
            old->child->group = ctx->list_head;
            old->child->subshell = 0;
            *ctx = *old;   /* physical copy */
            free(old);
        }
        b_reset(dest);
        return 1;
    }
    return 0;
}
#else
#define reserved_word(dest, ctx) ((int)0)
#endif

/* Normal return is 0.
 * Syntax or xglob errors return 1. */
static int done_word(o_string *dest, struct p_context *ctx)
{
    struct child_prog *child = ctx->child;
    glob_t *glob_target;
    int gr, flags = 0;

    debug_printf_parse("done_word entered: '%s' %p\n", dest->data, child);
    if (dest->length == 0 && !dest->nonnull) {
        debug_printf_parse("done_word return 0: true null, ignored\n");
        return 0;
    }
    if (ctx->pending_redirect) {
        glob_target = &ctx->pending_redirect->word;
    } else {
        if (child->group) {
            syntax(NULL);
            debug_printf_parse("done_word return 1: syntax error, groups and arglists don't mix\n");
            return 1;
        }
        if (!child->argv && (ctx->parse_type & PARSEFLAG_SEMICOLON)) {
            debug_printf_parse(": checking '%s' for reserved-ness\n", dest->data);
            if (reserved_word(dest, ctx)) {
                debug_printf_parse("done_word return %d\n", (ctx->res_w == RES_SNTX));
                return (ctx->res_w == RES_SNTX);
            }
        }
        glob_target = &child->glob_result;
        if (child->argv)
            flags |= GLOB_APPEND;
    }
    gr = xglob(dest, flags, glob_target);
    if (gr != 0) {
        debug_printf_parse("done_word return 1: xglob returned %d\n", gr);
        return 1;
    }

    b_reset(dest);
    if (ctx->pending_redirect) {
        ctx->pending_redirect = NULL;
        if (glob_target->gl_pathc != 1) {
            bb_error_msg("ambiguous redirect");
            debug_printf_parse("done_word return 1: ambiguous redirect\n");
            return 1;
        }
    } else {
        child->argv = glob_target->gl_pathv;
    }
#if ENABLE_HUSH_LOOPS
    if (ctx->res_w == RES_FOR) {
        done_word(dest, ctx);
        done_pipe(ctx, PIPE_SEQ);
    }
#endif
    debug_printf_parse("done_word return 0\n");
    return 0;
}

/* The only possible error here is out of memory, in which case
 * xmalloc exits. */
static int done_command(struct p_context *ctx)
{
    /* The child is really already in the pipe structure, so
     * advance the pipe counter and make a new, null child. */
    struct pipe *pi = ctx->pipe;
    struct child_prog *child = ctx->child;

    if (child) {
        if (child->group == NULL
         && child->argv == NULL
         && child->redirects == NULL
        ) {
            debug_printf_parse("done_command: skipping null cmd, num_progs=%d\n", pi->num_progs);
            return pi->num_progs;
        }
        pi->num_progs++;
        debug_printf_parse("done_command: ++num_progs=%d\n", pi->num_progs);
    } else {
        debug_printf_parse("done_command: initializing, num_progs=%d\n", pi->num_progs);
    }

    /* Only real trickiness here is that the uncommitted
     * child structure is not counted in pi->num_progs. */
    pi->progs = xrealloc(pi->progs, sizeof(*pi->progs) * (pi->num_progs+1));
    child = &pi->progs[pi->num_progs];

    memset(child, 0, sizeof(*child));
    /*child->redirects = NULL;*/
    /*child->argv = NULL;*/
    /*child->is_stopped = 0;*/
    /*child->group = NULL;*/
    /*child->glob_result.gl_pathv = NULL;*/
    child->family = pi;
    //sp: /*child->sp = 0;*/
    //pt: child->parse_type = ctx->parse_type;

    ctx->child = child;
    /* but ctx->pipe and ctx->list_head remain unchanged */

    return pi->num_progs; /* used only for 0/nonzero check */
}

static int done_pipe(struct p_context *ctx, pipe_style type)
{
    struct pipe *new_p;
    int not_null;

    debug_printf_parse("done_pipe entered, followup %d\n", type);
    not_null = done_command(ctx);  /* implicit closure of previous command */
    ctx->pipe->followup = type;
    ctx->pipe->res_word = ctx->res_w;
    /* Without this check, even just <enter> on command line generates
     * tree of three NOPs (!). Which is harmless but annoying.
     * IOW: it is safe to do it unconditionally. */
    if (not_null) {
        new_p = new_pipe();
        ctx->pipe->next = new_p;
        ctx->pipe = new_p;
        ctx->child = NULL;
        done_command(ctx);  /* set up new pipe to accept commands */
    }
    debug_printf_parse("done_pipe return 0\n");
    return 0;
}

/* peek ahead in the in_str to find out if we have a "&n" construct,
 * as in "2>&1", that represents duplicating a file descriptor.
 * returns either -2 (syntax error), -1 (no &), or the number found.
 */
static int redirect_dup_num(struct in_str *input)
{
    int ch, d = 0, ok = 0;
    ch = b_peek(input);
    if (ch != '&') return -1;

    b_getch(input);  /* get the & */
    ch = b_peek(input);
    if (ch == '-') {
        b_getch(input);
        return -3;  /* "-" represents "close me" */
    }
    while (isdigit(ch)) {
        d = d*10 + (ch-'0');
        ok = 1;
        b_getch(input);
        ch = b_peek(input);
    }
    if (ok) return d;

    bb_error_msg("ambiguous redirect");
    return -2;
}

/* If a redirect is immediately preceded by a number, that number is
 * supposed to tell which file descriptor to redirect.  This routine
 * looks for such preceding numbers.  In an ideal world this routine
 * needs to handle all the following classes of redirects...
 *     echo 2>foo     # redirects fd  2 to file "foo", nothing passed to echo
 *     echo 49>foo    # redirects fd 49 to file "foo", nothing passed to echo
 *     echo -2>foo    # redirects fd  1 to file "foo",    "-2" passed to echo
 *     echo 49x>foo   # redirects fd  1 to file "foo",   "49x" passed to echo
 * A -1 output from this program means no valid number was found, so the
 * caller should use the appropriate default for this redirection.
 */
static int redirect_opt_num(o_string *o)
{
    int num;

    if (o->length == 0)
        return -1;
    for (num = 0; num < o->length; num++) {
        if (!isdigit(*(o->data + num))) {
            return -1;
        }
    }
    /* reuse num (and save an int) */
    num = atoi(o->data);
    b_reset(o);
    return num;
}

#if ENABLE_HUSH_TICK
static FILE *generate_stream_from_list(struct pipe *head)
{
    FILE *pf;
    int pid, channel[2];

    xpipe(channel);
#if BB_MMU
    pid = fork();
#else
    pid = vfork();
#endif
    if (pid < 0) {
        bb_perror_msg_and_die("fork");
    } else if (pid == 0) {
        close(channel[0]);
        if (channel[1] != 1) {
            dup2(channel[1], 1);
            close(channel[1]);
        }
        /* Prevent it from trying to handle ctrl-z etc */
#if ENABLE_HUSH_JOB
        run_list_level = 1;
#endif
        /* Process substitution is not considered to be usual
         * 'command execution'.
         * SUSv3 says ctrl-Z should be ignored, ctrl-C should not. */
        /* Not needed, we are relying on it being disabled
         * everywhere outside actual command execution. */
        /*set_jobctrl_sighandler(SIG_IGN);*/
        set_misc_sighandler(SIG_DFL);
        _exit(run_list_real(head));   /* leaks memory */
    }
    close(channel[1]);
    pf = fdopen(channel[0], "r");
    return pf;
}

/* Return code is exit status of the process that is run. */
static int process_command_subs(o_string *dest, struct p_context *ctx,
    struct in_str *input, const char *subst_end)
{
    int retcode, ch, eol_cnt;
    o_string result = NULL_O_STRING;
    struct p_context inner;
    FILE *p;
    struct in_str pipe_str;

    initialize_context(&inner);

    /* recursion to generate command */
    retcode = parse_stream(&result, &inner, input, subst_end);
    if (retcode != 0)
        return retcode;  /* syntax error or EOF */
    done_word(&result, &inner);
    done_pipe(&inner, PIPE_SEQ);
    b_free(&result);

    p = generate_stream_from_list(inner.list_head);
    if (p == NULL) return 1;
    mark_open(fileno(p));
    setup_file_in_str(&pipe_str, p);

    /* now send results of command back into original context */
    eol_cnt = 0;
    while ((ch = b_getch(&pipe_str)) != EOF) {
        if (ch == '\n') {
            eol_cnt++;
            continue;
        }
        while (eol_cnt) {
            b_addqchr(dest, '\n', dest->quote);
            eol_cnt--;
        }
        b_addqchr(dest, ch, dest->quote);
    }

    debug_printf("done reading from pipe, pclose()ing\n");
    /* This is the step that wait()s for the child.  Should be pretty
     * safe, since we just read an EOF from its stdout.  We could try
     * to do better, by using wait(), and keeping track of background jobs
     * at the same time.  That would be a lot of work, and contrary
     * to the KISS philosophy of this program. */
    mark_closed(fileno(p));
    retcode = fclose(p);
    free_pipe_list(inner.list_head, 0);
    debug_printf("closed FILE from child, retcode=%d\n", retcode);
    return retcode;
}
#endif

static int parse_group(o_string *dest, struct p_context *ctx,
    struct in_str *input, int ch)
{
    int rcode;
    const char *endch = NULL;
    struct p_context sub;
    struct child_prog *child = ctx->child;

    debug_printf_parse("parse_group entered\n");
    if (child->argv) {
        syntax(NULL);
        debug_printf_parse("parse_group return 1: syntax error, groups and arglists don't mix\n");
        return 1;
    }
    initialize_context(&sub);
    endch = "}";
    if (ch == '(') {
        endch = ")";
        child->subshell = 1;
    }
    rcode = parse_stream(dest, &sub, input, endch);
//vda: err chk?
    done_word(dest, &sub); /* finish off the final word in the subcontext */
    done_pipe(&sub, PIPE_SEQ);  /* and the final command there, too */
    child->group = sub.list_head;

    debug_printf_parse("parse_group return %d\n", rcode);
    return rcode;
    /* child remains "open", available for possible redirects */
}

/* Basically useful version until someone wants to get fancier,
 * see the bash man page under "Parameter Expansion" */
static const char *lookup_param(const char *src)
{
    struct variable *var = get_local_var(src);
    if (var)
        return strchr(var->varstr, '=') + 1;
    return NULL;
}

/* return code: 0 for OK, 1 for syntax error */
static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input)
{
    int ch = b_peek(input);  /* first character after the $ */
    unsigned char quote_mask = dest->quote ? 0x80 : 0;

    debug_printf_parse("handle_dollar entered: ch='%c'\n", ch);
    if (isalpha(ch)) {
        b_addchr(dest, SPECIAL_VAR_SYMBOL);
        //sp: ctx->child->sp++;
        while (1) {
            debug_printf_parse(": '%c'\n", ch);
            b_getch(input);
            b_addchr(dest, ch | quote_mask);
            quote_mask = 0;
            ch = b_peek(input);
            if (!isalnum(ch) && ch != '_')
                break;
        }
        b_addchr(dest, SPECIAL_VAR_SYMBOL);
    } else if (isdigit(ch)) {
 make_one_char_var:
        b_addchr(dest, SPECIAL_VAR_SYMBOL);
        //sp: ctx->child->sp++;
        debug_printf_parse(": '%c'\n", ch);
        b_getch(input);
        b_addchr(dest, ch | quote_mask);
        b_addchr(dest, SPECIAL_VAR_SYMBOL);
    } else switch (ch) {
        case '$': /* pid */
        case '!': /* last bg pid */
        case '?': /* last exit code */
        case '#': /* number of args */
        case '*': /* args */
        case '@': /* args */
            goto make_one_char_var;
        case '{':
            b_addchr(dest, SPECIAL_VAR_SYMBOL);
            //sp: ctx->child->sp++;
            b_getch(input);
            /* XXX maybe someone will try to escape the '}' */
            while (1) {
                ch = b_getch(input);
                if (ch == '}')
                    break;
                if (!isalnum(ch) && ch != '_') {
                    syntax("unterminated ${name}");
                    debug_printf_parse("handle_dollar return 1: unterminated ${name}\n");
                    return 1;
                }
                debug_printf_parse(": '%c'\n", ch);
                b_addchr(dest, ch | quote_mask);
                quote_mask = 0;
            }
            b_addchr(dest, SPECIAL_VAR_SYMBOL);
            break;
#if ENABLE_HUSH_TICK
        case '(':
            b_getch(input);
            process_command_subs(dest, ctx, input, ")");
            break;
#endif
        case '-':
        case '_':
            /* still unhandled, but should be eventually */
            bb_error_msg("unhandled syntax: $%c", ch);
            return 1;
            break;
        default:
            b_addqchr(dest, '$', dest->quote);
    }
    debug_printf_parse("handle_dollar return 0\n");
    return 0;
}

/* return code is 0 for normal exit, 1 for syntax error */
static int parse_stream(o_string *dest, struct p_context *ctx,
    struct in_str *input, const char *end_trigger)
{
    int ch, m;
    int redir_fd;
    redir_type redir_style;
    int next;

    /* Only double-quote state is handled in the state variable dest->quote.
     * A single-quote triggers a bypass of the main loop until its mate is
     * found.  When recursing, quote state is passed in via dest->quote. */

    debug_printf_parse("parse_stream entered, end_trigger='%s'\n", end_trigger);

    while (1) {
        m = CHAR_IFS;
        next = '\0';
        ch = b_getch(input);
        if (ch != EOF) {
            m = charmap[ch];
            if (ch != '\n')
                next = b_peek(input);
        }
        debug_printf_parse(": ch=%c (%d) m=%d quote=%d\n",
                        ch, ch, m, dest->quote);
        if (m == CHAR_ORDINARY
         || (m != CHAR_SPECIAL && dest->quote)
        ) {
            if (ch == EOF) {
                syntax("unterminated \"");
                debug_printf_parse("parse_stream return 1: unterminated \"\n");
                return 1;
            }
            b_addqchr(dest, ch, dest->quote);
            continue;
        }
        if (m == CHAR_IFS) {
            if (done_word(dest, ctx)) {
                debug_printf_parse("parse_stream return 1: done_word!=0\n");
                return 1;
            }
            if (ch == EOF)
                break;
            /* If we aren't performing a substitution, treat
             * a newline as a command separator.
             * [why we don't handle it exactly like ';'? --vda] */
            if (end_trigger && ch == '\n') {
                done_pipe(ctx, PIPE_SEQ);
            }
        }
        if ((end_trigger && strchr(end_trigger, ch))
         && !dest->quote && ctx->res_w == RES_NONE
        ) {
            debug_printf_parse("parse_stream return 0: end_trigger char found\n");
            return 0;
        }
        if (m == CHAR_IFS)
            continue;
        switch (ch) {
        case '#':
            if (dest->length == 0 && !dest->quote) {
                while (1) {
                    ch = b_peek(input);
                    if (ch == EOF || ch == '\n')
                        break;
                    b_getch(input);
                }
            } else {
                b_addqchr(dest, ch, dest->quote);
            }
            break;
        case '\\':
            if (next == EOF) {
                syntax("\\<eof>");
                debug_printf_parse("parse_stream return 1: \\<eof>\n");
                return 1;
            }
            b_addqchr(dest, '\\', dest->quote);
            b_addqchr(dest, b_getch(input), dest->quote);
            break;
        case '$':
            if (handle_dollar(dest, ctx, input) != 0) {
                debug_printf_parse("parse_stream return 1: handle_dollar returned non-0\n");
                return 1;
            }
            break;
        case '\'':
            dest->nonnull = 1;
            while (1) {
                ch = b_getch(input);
                if (ch == EOF || ch == '\'')
                    break;
                b_addchr(dest, ch);
            }
            if (ch == EOF) {
                syntax("unterminated '");
                debug_printf_parse("parse_stream return 1: unterminated '\n");
                return 1;
            }
            break;
        case '"':
            dest->nonnull = 1;
            dest->quote = !dest->quote;
            break;
#if ENABLE_HUSH_TICK
        case '`':
            process_command_subs(dest, ctx, input, "`");
            break;
#endif
        case '>':
            redir_fd = redirect_opt_num(dest);
            done_word(dest, ctx);
            redir_style = REDIRECT_OVERWRITE;
            if (next == '>') {
                redir_style = REDIRECT_APPEND;
                b_getch(input);
            }
#if 0
            else if (next == '(') {
                syntax(">(process) not supported");
                debug_printf_parse("parse_stream return 1: >(process) not supported\n");
                return 1;
            }
#endif
            setup_redirect(ctx, redir_fd, redir_style, input);
            break;
        case '<':
            redir_fd = redirect_opt_num(dest);
            done_word(dest, ctx);
            redir_style = REDIRECT_INPUT;
            if (next == '<') {
                redir_style = REDIRECT_HEREIS;
                b_getch(input);
            } else if (next == '>') {
                redir_style = REDIRECT_IO;
                b_getch(input);
            }
#if 0
            else if (next == '(') {
                syntax("<(process) not supported");
                debug_printf_parse("parse_stream return 1: <(process) not supported\n");
                return 1;
            }
#endif
            setup_redirect(ctx, redir_fd, redir_style, input);
            break;
        case ';':
            done_word(dest, ctx);
            done_pipe(ctx, PIPE_SEQ);
            break;
        case '&':
            done_word(dest, ctx);
            if (next == '&') {
                b_getch(input);
                done_pipe(ctx, PIPE_AND);
            } else {
                done_pipe(ctx, PIPE_BG);
            }
            break;
        case '|':
            done_word(dest, ctx);
            if (next == '|') {
                b_getch(input);
                done_pipe(ctx, PIPE_OR);
            } else {
                /* we could pick up a file descriptor choice here
                 * with redirect_opt_num(), but bash doesn't do it.
                 * "echo foo 2| cat" yields "foo 2". */
                done_command(ctx);
            }
            break;
        case '(':
        case '{':
            if (parse_group(dest, ctx, input, ch) != 0) {
                debug_printf_parse("parse_stream return 1: parse_group returned non-0\n");
                return 1;
            }
            break;
        case ')':
        case '}':
            syntax("unexpected }");   /* Proper use of this character is caught by end_trigger */
            debug_printf_parse("parse_stream return 1: unexpected '}'\n");
            return 1;
        default:
            if (ENABLE_HUSH_DEBUG)
                bb_error_msg_and_die("BUG: unexpected %c\n", ch);
        }
    }
    /* Complain if quote?  No, maybe we just finished a command substitution
     * that was quoted.  Example:
     * $ echo "`cat foo` plus more"
     * and we just got the EOF generated by the subshell that ran "cat foo"
     * The only real complaint is if we got an EOF when end_trigger != NULL,
     * that is, we were really supposed to get end_trigger, and never got
     * one before the EOF.  Can't use the standard "syntax error" return code,
     * so that parse_stream_outer can distinguish the EOF and exit smoothly. */
    debug_printf_parse("parse_stream return %d\n", -(end_trigger != NULL));
    if (end_trigger)
        return -1;
    return 0;
}

static void set_in_charmap(const char *set, int code)
{
    while (*set)
        charmap[(unsigned char)*set++] = code;
}

static void update_charmap(void)
{
    /* char *ifs and char charmap[256] are both globals. */
    ifs = getenv("IFS");
    if (ifs == NULL)
        ifs = " \t\n";
    /* Precompute a list of 'flow through' behavior so it can be treated
     * quickly up front.  Computation is necessary because of IFS.
     * Special case handling of IFS == " \t\n" is not implemented.
     * The charmap[] array only really needs two bits each,
     * and on most machines that would be faster (reduced L1 cache use).
     */
    memset(charmap, CHAR_ORDINARY, sizeof(charmap));
#if ENABLE_HUSH_TICK
    set_in_charmap("\\$\"`", CHAR_SPECIAL);
#else
    set_in_charmap("\\$\"", CHAR_SPECIAL);
#endif
    set_in_charmap("<>;&|(){}#'", CHAR_ORDINARY_IF_QUOTED);
    set_in_charmap(ifs, CHAR_IFS);  /* are ordinary if quoted */
}

/* most recursion does not come through here, the exception is
 * from builtin_source() and builtin_eval() */
static int parse_and_run_stream(struct in_str *inp, int parse_flag)
{
    struct p_context ctx;
    o_string temp = NULL_O_STRING;
    int rcode;
    do {
        ctx.parse_type = parse_flag;
        initialize_context(&ctx);
        update_charmap();
        if (!(parse_flag & PARSEFLAG_SEMICOLON) || (parse_flag & PARSEFLAG_REPARSING))
            set_in_charmap(";$&|", CHAR_ORDINARY);
#if ENABLE_HUSH_INTERACTIVE
        inp->promptmode = 0; /* PS1 */
#endif
        /* We will stop & execute after each ';' or '\n'.
         * Example: "sleep 9999; echo TEST" + ctrl-C:
         * TEST should be printed */
        rcode = parse_stream(&temp, &ctx, inp, ";\n");
        if (rcode != 1 && ctx.old_flag != 0) {
            syntax(NULL);
        }
        if (rcode != 1 && ctx.old_flag == 0) {
            done_word(&temp, &ctx);
            done_pipe(&ctx, PIPE_SEQ);
            debug_print_tree(ctx.list_head, 0);
            debug_printf_exec("parse_stream_outer: run_list\n");
            run_list(ctx.list_head);
        } else {
            if (ctx.old_flag != 0) {
                free(ctx.stack);
                b_reset(&temp);
            }
            temp.nonnull = 0;
            temp.quote = 0;
            inp->p = NULL;
            free_pipe_list(ctx.list_head, 0);
        }
        b_free(&temp);
    } while (rcode != -1 && !(parse_flag & PARSEFLAG_EXIT_FROM_LOOP));   /* loop on syntax errors, return on EOF */
    return 0;
}

static int parse_and_run_string(const char *s, int parse_flag)
{
    struct in_str input;
    setup_string_in_str(&input, s);
    return parse_and_run_stream(&input, parse_flag);
}

static int parse_and_run_file(FILE *f)
{
    int rcode;
    struct in_str input;
    setup_file_in_str(&input, f);
    rcode = parse_and_run_stream(&input, PARSEFLAG_SEMICOLON);
    return rcode;
}

#if ENABLE_HUSH_JOB
/* Make sure we have a controlling tty.  If we get started under a job
 * aware app (like bash for example), make sure we are now in charge so
 * we don't fight over who gets the foreground */
static void setup_job_control(void)
{
    pid_t shell_pgrp;

    saved_task_pgrp = shell_pgrp = getpgrp();
    debug_printf_jobs("saved_task_pgrp=%d\n", saved_task_pgrp);
    fcntl(interactive_fd, F_SETFD, FD_CLOEXEC);

    /* If we were ran as 'hush &',
     * sleep until we are in the foreground.  */
    while (tcgetpgrp(interactive_fd) != shell_pgrp) {
        /* Send TTIN to ourself (should stop us) */
        kill(- shell_pgrp, SIGTTIN);
        shell_pgrp = getpgrp();
    }

    /* Ignore job-control and misc signals.  */
    set_jobctrl_sighandler(SIG_IGN);
    set_misc_sighandler(SIG_IGN);
//huh?  signal(SIGCHLD, SIG_IGN);

    /* We _must_ restore tty pgrp on fatal signals */
    set_fatal_sighandler(sigexit);

    /* Put ourselves in our own process group.  */
    setpgrp(); /* is the same as setpgid(our_pid, our_pid); */
    /* Grab control of the terminal.  */
    tcsetpgrp(interactive_fd, getpid());
}
#endif

int hush_main(int argc, char **argv);
int hush_main(int argc, char **argv)
{
    static const char version_str[] ALIGN1 = "HUSH_VERSION="HUSH_VER_STR;
    static const struct variable const_shell_ver = {
        .next = NULL,
        .varstr = (char*)version_str,
        .max_len = 1, /* 0 can provoke free(name) */
        .flg_export = 1,
        .flg_read_only = 1,
    };

    int opt;
    FILE *input;
    char **e;
    struct variable *cur_var;

    PTR_TO_GLOBALS = xzalloc(sizeof(G));

    /* Deal with HUSH_VERSION */
    shell_ver = const_shell_ver; /* copying struct here */
    top_var = &shell_ver;
    unsetenv("HUSH_VERSION"); /* in case it exists in initial env */
    /* Initialize our shell local variables with the values
     * currently living in the environment */
    cur_var = top_var;
    e = environ;
    if (e) while (*e) {
        char *value = strchr(*e, '=');
        if (value) { /* paranoia */
            cur_var->next = xzalloc(sizeof(*cur_var));
            cur_var = cur_var->next;
            cur_var->varstr = *e;
            cur_var->max_len = strlen(*e);
            cur_var->flg_export = 1;
        }
        e++;
    }
    putenv((char *)version_str); /* reinstate HUSH_VERSION */

#if ENABLE_FEATURE_EDITING
    line_input_state = new_line_input_t(FOR_SHELL);
#endif
    /* XXX what should these be while sourcing /etc/profile? */
    global_argc = argc;
    global_argv = argv;
    /* Initialize some more globals to non-zero values */
    set_cwd();
#if ENABLE_HUSH_INTERACTIVE
#if ENABLE_FEATURE_EDITING
    cmdedit_set_initial_prompt();
#endif
    PS2 = "> ";
#endif

    if (EXIT_SUCCESS) /* otherwise is already done */
        last_return_code = EXIT_SUCCESS;

    if (argv[0] && argv[0][0] == '-') {
        debug_printf("sourcing /etc/profile\n");
        input = fopen("/etc/profile", "r");
        if (input != NULL) {
            mark_open(fileno(input));
            parse_and_run_file(input);
            mark_closed(fileno(input));
            fclose(input);
        }
    }
    input = stdin;

    while ((opt = getopt(argc, argv, "c:xif")) > 0) {
        switch (opt) {
        case 'c':
            global_argv = argv + optind;
            global_argc = argc - optind;
            opt = parse_and_run_string(optarg, PARSEFLAG_SEMICOLON);
            goto final_return;
        case 'i':
            /* Well, we cannot just declare interactiveness,
             * we have to have some stuff (ctty, etc) */
            /* interactive_fd++; */
            break;
        case 'f':
            fake_mode = 1;
            break;
        default:
#ifndef BB_VER
            fprintf(stderr, "Usage: sh [FILE]...\n"
                    "   or: sh -c command [args]...\n\n");
            exit(EXIT_FAILURE);
#else
            bb_show_usage();
#endif
        }
    }
#if ENABLE_HUSH_JOB
    /* A shell is interactive if the '-i' flag was given, or if all of
     * the following conditions are met:
     *    no -c command
     *    no arguments remaining or the -s flag given
     *    standard input is a terminal
     *    standard output is a terminal
     *    Refer to Posix.2, the description of the 'sh' utility. */
    if (argv[optind] == NULL && input == stdin
     && isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)
    ) {
        saved_tty_pgrp = tcgetpgrp(STDIN_FILENO);
        debug_printf("saved_tty_pgrp=%d\n", saved_tty_pgrp);
        if (saved_tty_pgrp >= 0) {
            /* try to dup to high fd#, >= 255 */
            interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
            if (interactive_fd < 0) {
                /* try to dup to any fd */
                interactive_fd = dup(STDIN_FILENO);
                if (interactive_fd < 0)
                    /* give up */
                    interactive_fd = 0;
            }
            // TODO: track & disallow any attempts of user
            // to (inadvertently) close/redirect it
        }
    }
    debug_printf("interactive_fd=%d\n", interactive_fd);
    if (interactive_fd) {
        /* Looks like they want an interactive shell */
        setup_job_control();
        /* Make xfuncs do cleanup on exit */
        die_sleep = -1; /* flag */
// FIXME: should we reset die_sleep = 0 whereever we fork?
        if (setjmp(die_jmp)) {
            /* xfunc has failed! die die die */
            hush_exit(xfunc_error_retval);
        }
#if !ENABLE_FEATURE_SH_EXTRA_QUIET
        printf("\n\n%s hush - the humble shell v"HUSH_VER_STR"\n", bb_banner);
        printf("Enter 'help' for a list of built-in commands.\n\n");
#endif
    }
#elif ENABLE_HUSH_INTERACTIVE
/* no job control compiled, only prompt/line editing */
    if (argv[optind] == NULL && input == stdin
     && isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)
    ) {
        interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
        if (interactive_fd < 0) {
            /* try to dup to any fd */
            interactive_fd = dup(STDIN_FILENO);
            if (interactive_fd < 0)
                /* give up */
                interactive_fd = 0;
        }
    }

#endif

    if (argv[optind] == NULL) {
        opt = parse_and_run_file(stdin);
        goto final_return;
    }

    debug_printf("\nrunning script '%s'\n", argv[optind]);
    global_argv = argv + optind;
    global_argc = argc - optind;
    input = xfopen(argv[optind], "r");
    opt = parse_and_run_file(input);

 final_return:

#if ENABLE_FEATURE_CLEAN_UP
    fclose(input);
    if (cwd != bb_msg_unknown)
        free((char*)cwd);
    cur_var = top_var->next;
    while (cur_var) {
        struct variable *tmp = cur_var;
        if (!cur_var->max_len)
            free(cur_var->varstr);
        cur_var = cur_var->next;
        free(tmp);
    }
#endif
    hush_exit(opt ? opt : last_return_code);
}