source: MondoRescue/branches/stable/mindi-busybox/debianutils/start_stop_daemon.c@ 1770

/* vi: set sw=4 ts=4: */
/*
 * Mini start-stop-daemon implementation(s) for busybox
 *
 * Written by Marek Michalkiewicz <marekm@i17linuxb.ists.pwr.wroc.pl>,
 * Adapted for busybox David Kimdon <dwhedon@gordian.com>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

/* NB: we have a problem here with /proc/NN/exe usage, similar to
 * one fixed in killall/pidof */

#include <getopt.h>
#include <sys/resource.h>

/* Override ENABLE_FEATURE_PIDFILE */
#define WANT_PIDFILE 1
#include "libbb.h"

static int signal_nr = 15;
static int user_id = -1;
static char *userspec;
static char *cmdname;
static char *execname;
static char *pidfile;
static smallint quiet;

struct pid_list {
    struct pid_list *next;
    pid_t pid;
};

static struct pid_list *found;

static int pid_is_exec(pid_t pid, const char *name)
{
    char buf[sizeof("/proc//exe") + sizeof(int)*3];
    char *execbuf;
    int n;

    sprintf(buf, "/proc/%u/exe", pid);
    n = strlen(name) + 1;
    execbuf = xzalloc(n + 1);
    readlink(buf, execbuf, n);

    /* if readlink fails, execbuf still contains "" */
    n = strcmp(execbuf, name);
    if (ENABLE_FEATURE_CLEAN_UP)
        free(execbuf);
    return !n; /* nonzero (true) if execbuf == name */
}

static int pid_is_user(int pid, int uid)
{
    struct stat sb;
    char buf[sizeof("/proc/") + sizeof(int)*3];

    sprintf(buf, "/proc/%u", pid);
    if (stat(buf, &sb) != 0)
        return 0;
    return (sb.st_uid == uid);
}

static int pid_is_cmd(pid_t pid, const char *name)
{
    char fname[sizeof("/proc//stat") + sizeof(int)*3];
    char *buf;
    int r = 0;

    sprintf(fname, "/proc/%u/stat", pid);
    buf = xmalloc_open_read_close(fname, NULL);
    if (buf) {
        char *p = strchr(buf, '(');
        if (p) {
            char *pe = strrchr(++p, ')');
            if (pe) {
                *pe = '\0';
                r = !strcmp(p, name);
            }
        }
        free(buf);
    }
    return r;
}

static void check(int pid)
{
    struct pid_list *p;

    if (execname && !pid_is_exec(pid, execname)) {
        return;
    }
    if (userspec && !pid_is_user(pid, user_id)) {
        return;
    }
    if (cmdname && !pid_is_cmd(pid, cmdname)) {
        return;
    }
    p = xmalloc(sizeof(*p));
    p->next = found;
    p->pid = pid;
    found = p;
}

static void do_pidfile(void)
{
    FILE *f;
    unsigned pid;

    f = fopen(pidfile, "r");
    if (f) {
        if (fscanf(f, "%u", &pid) == 1)
            check(pid);
        fclose(f);
    } else if (errno != ENOENT)
        bb_perror_msg_and_die("open pidfile %s", pidfile);
}

static void do_procinit(void)
{
    DIR *procdir;
    struct dirent *entry;
    int foundany, pid;

    if (pidfile) {
        do_pidfile();
        return;
    }

    procdir = xopendir("/proc");

    foundany = 0;
    while ((entry = readdir(procdir)) != NULL) {
        pid = bb_strtou(entry->d_name, NULL, 10);
        if (errno)
            continue;
        foundany++;
        check(pid);
    }
    closedir(procdir);
    if (!foundany)
        bb_error_msg_and_die("nothing in /proc - not mounted?");
}

static int do_stop(void)
{
    char *what;
    struct pid_list *p;
    int killed = 0;

    do_procinit();

    if (cmdname) {
        if (ENABLE_FEATURE_CLEAN_UP) what = xstrdup(cmdname);
        if (!ENABLE_FEATURE_CLEAN_UP) what = cmdname;
    } else if (execname) {
        if (ENABLE_FEATURE_CLEAN_UP) what = xstrdup(execname);
        if (!ENABLE_FEATURE_CLEAN_UP) what = execname;
    } else if (pidfile)
        what = xasprintf("process in pidfile '%s'", pidfile);
    else if (userspec)
        what = xasprintf("process(es) owned by '%s'", userspec);
    else
        bb_error_msg_and_die("internal error, please report");

    if (!found) {
        if (!quiet)
            printf("no %s found; none killed\n", what);
        killed = -1;
        goto ret;
    }
    for (p = found; p; p = p->next) {
        if (kill(p->pid, signal_nr) == 0) {
            p->pid = - p->pid;
            killed++;
        } else {
            bb_perror_msg("warning: killing process %u", p->pid);
        }
    }
    if (!quiet && killed) {
        printf("stopped %s (pid", what);
        for (p = found; p; p = p->next)
            if (p->pid < 0)
                printf(" %u", - p->pid);
        puts(")");
    }
 ret:
    if (ENABLE_FEATURE_CLEAN_UP)
        free(what);
    return killed;
}

#if ENABLE_FEATURE_START_STOP_DAEMON_LONG_OPTIONS
static const char start_stop_daemon_longopts[] ALIGN1 =
    "stop\0"         No_argument       "K"
    "start\0"        No_argument       "S"
    "background\0"   No_argument       "b"
    "quiet\0"        No_argument       "q"
    "make-pidfile\0" No_argument       "m"
#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
    "oknodo\0"       No_argument       "o"
    "verbose\0"      No_argument       "v"
    "nicelevel\0"    Required_argument "N"
#endif
    "startas\0"      Required_argument "a"
    "name\0"         Required_argument "n"
    "signal\0"       Required_argument "s"
    "user\0"         Required_argument "u"
    "chuid\0"        Required_argument "c"
    "exec\0"         Required_argument "x"
    "pidfile\0"      Required_argument "p"
#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
    "retry\0"        Required_argument "R"
#endif
    ;
#endif

enum {
    CTX_STOP       = 0x1,
    CTX_START      = 0x2,
    OPT_BACKGROUND = 0x4, // -b
    OPT_QUIET      = 0x8, // -q
    OPT_MAKEPID    = 0x10, // -m
    OPT_a          = 0x20, // -a
    OPT_n          = 0x40, // -n
    OPT_s          = 0x80, // -s
    OPT_u          = 0x100, // -u
    OPT_c          = 0x200, // -c
    OPT_x          = 0x400, // -x
    OPT_p          = 0x800, // -p
    OPT_OKNODO     = 0x1000 * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -o
    OPT_VERBOSE    = 0x2000 * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -v
    OPT_NICELEVEL  = 0x4000 * ENABLE_FEATURE_START_STOP_DAEMON_FANCY, // -N
};

int start_stop_daemon_main(int argc, char **argv);
int start_stop_daemon_main(int argc, char **argv)
{
    unsigned opt;
    char *signame;
    char *startas;
    char *chuid;
#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
//  char *retry_arg = NULL;
//  int retries = -1;
    char *opt_N;
#endif
#if ENABLE_FEATURE_START_STOP_DAEMON_LONG_OPTIONS
    applet_long_options = start_stop_daemon_longopts;
#endif

    /* Check required one context option was given */
    opt_complementary = "K:S:K--S:S--K:m?p:K?xpun:S?xa";
    opt = getopt32(argv, "KSbqma:n:s:u:c:x:p:"
        USE_FEATURE_START_STOP_DAEMON_FANCY("ovN:"),
//      USE_FEATURE_START_STOP_DAEMON_FANCY("ovN:R:"),
        &startas, &cmdname, &signame, &userspec, &chuid, &execname, &pidfile
        USE_FEATURE_START_STOP_DAEMON_FANCY(,&opt_N)
//      USE_FEATURE_START_STOP_DAEMON_FANCY(,&retry_arg)
    );

    quiet = (opt & OPT_QUIET) && !(opt & OPT_VERBOSE);

    if (opt & OPT_s) {
        signal_nr = get_signum(signame);
        if (signal_nr < 0) bb_show_usage();
    }

    if (!(opt & OPT_a))
        startas = execname;

//  USE_FEATURE_START_STOP_DAEMON_FANCY(
//      if (retry_arg)
//          retries = xatoi_u(retry_arg);
//  )
    argc -= optind;
    argv += optind;

    if (userspec) {
        user_id = bb_strtou(userspec, NULL, 10);
        if (errno)
            user_id = xuname2uid(userspec);
    }

    if (opt & CTX_STOP) {
        int i = do_stop();
        return (opt & OPT_OKNODO) ? 0 : (i <= 0);
    }

    do_procinit();

    if (found) {
        if (!quiet)
            printf("%s already running\n%d\n", execname, found->pid);
        return !(opt & OPT_OKNODO);
    }
    *--argv = startas;
    if (opt & OPT_BACKGROUND) {
#if BB_MMU
        bb_daemonize(0);
#else
        pid_t pid = vfork();
        if (pid < 0) /* error */
            bb_perror_msg_and_die("vfork");
        if (pid != 0) {
            /* parent */
            /* why _exit? the child may have changed the stack,
             * so "return 0" may do bad things */
            _exit(0);
        }
        /* child */
        setsid(); /* detach from controlling tty */
        /* Redirect stdio to /dev/null, close extra FDs.
         * We do not actually daemonize because of DAEMON_ONLY_SANITIZE */
        bb_daemonize_or_rexec(
            DAEMON_DEVNULL_STDIO
            + DAEMON_CLOSE_EXTRA_FDS
            + DAEMON_ONLY_SANITIZE,
            NULL /* argv, unused */ );
#endif
    }
    if (opt & OPT_MAKEPID) {
        /* user wants _us_ to make the pidfile */
        write_pidfile(pidfile);
    }
    if (opt & OPT_c) {
        struct bb_uidgid_t ugid;
        parse_chown_usergroup_or_die(&ugid, chuid);
        if (ugid.gid != (gid_t) -1) xsetgid(ugid.gid);
        if (ugid.uid != (uid_t) -1) xsetuid(ugid.uid);
    }
#if ENABLE_FEATURE_START_STOP_DAEMON_FANCY
    if (opt & OPT_NICELEVEL) {
        /* Set process priority */
        int prio = getpriority(PRIO_PROCESS, 0) + xatoi_range(opt_N, INT_MIN/2, INT_MAX/2);
        if (setpriority(PRIO_PROCESS, 0, prio) < 0) {
            bb_perror_msg_and_die("setpriority(%d)", prio);
        }
    }
#endif
    execv(startas, argv);
    bb_perror_msg_and_die("cannot start %s", startas);
}