source: branches/2.2.5/mindi-busybox/shell/bbsh.c @ 1765

Last change on this file since 1765 was 1765, checked in by Bruno Cornec, 13 years ago

Update to busybox 1.7.2

  • Property svn:eol-style set to native
File size: 5.0 KB
Line 
1/* vi: set ts=4 :
2 *
3 * bbsh - busybox shell
4 *
5 * Copyright 2006 Rob Landley <rob@landley.net>
6 *
7 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
8 */
9
10// A section of code that gets repeatedly or conditionally executed is stored
11// as a string and parsed each time it's run.
12
13
14
15// Wheee, debugging.
16
17// Terminal control
18#define ENABLE_BBSH_TTY        0
19
20// &, fg, bg, jobs.  (ctrl-z with tty.)
21#define ENABLE_BBSH_JOBCTL     0
22
23// Flow control (if, while, for, functions { })
24#define ENABLE_BBSH_FLOWCTL    0
25
26#define ENABLE_BBSH_ENVVARS    0  // Environment variable support
27
28// Local and synthetic variables, fancy prompts, set, $?, etc.
29#define ENABLE_BBSH_LOCALVARS  0
30
31// Pipes and redirects: | > < >> << && || & () ;
32#define ENABLE_BBSH_PIPES      0
33
34/* Fun:
35
36  echo `echo hello#comment " woot` and more
37*/
38
39#include "libbb.h"
40
41// A single executable, its arguments, and other information we know about it.
42#define BBSH_FLAG_EXIT    1
43#define BBSH_FLAG_SUSPEND 2
44#define BBSH_FLAG_PIPE    4
45#define BBSH_FLAG_AND     8
46#define BBSH_FLAG_OR      16
47#define BBSH_FLAG_AMP     32
48#define BBSH_FLAG_SEMI    64
49#define BBSH_FLAG_PAREN   128
50
51// What we know about a single process.
52struct command {
53    struct command *next;
54    int flags;      // exit, suspend, && ||
55    int pid;        // pid (or exit code)
56    int argc;
57    char *argv[0];
58};
59
60// A collection of processes piped into/waiting on each other.
61struct pipeline {
62    struct pipeline *next;
63    int job_id;
64    struct command *cmd;
65    char *cmdline;
66    int cmdlinelen;
67};
68
69static void free_list(void *list, void (*freeit)(void *data))
70{
71    while (list) {
72        void **next = (void **)list;
73        void *list_next = *next;
74        freeit(list);
75        free(list);
76        list = list_next;
77    }
78}
79
80// Parse one word from the command line, appending one or more argv[] entries
81// to struct command.  Handles environment variable substitution and
82// substrings.  Returns pointer to next used byte, or NULL if it
83// hit an ending token.
84static char *parse_word(char *start, struct command **cmd)
85{
86    char *end;
87
88    // Detect end of line (and truncate line at comment)
89    if (ENABLE_BBSH_PIPES && strchr("><&|(;", *start)) return 0;
90
91    // Grab next word.  (Add dequote and envvar logic here)
92    end = start;
93    end = skip_non_whitespace(end);
94    (*cmd)->argv[(*cmd)->argc++] = xstrndup(start, end-start);
95
96    // Allocate more space if there's no room for NULL terminator.
97
98    if (!((*cmd)->argc & 7))
99            *cmd = xrealloc(*cmd,
100                    sizeof(struct command) + ((*cmd)->argc+8)*sizeof(char *));
101    (*cmd)->argv[(*cmd)->argc] = 0;
102    return end;
103}
104
105// Parse a line of text into a pipeline.
106// Returns a pointer to the next line.
107
108static char *parse_pipeline(char *cmdline, struct pipeline *line)
109{
110    struct command **cmd = &(line->cmd);
111    char *start = line->cmdline = cmdline;
112
113    if (!cmdline) return 0;
114
115    if (ENABLE_BBSH_JOBCTL) line->cmdline = cmdline;
116
117    // Parse command into argv[]
118    for (;;) {
119        char *end;
120
121        // Skip leading whitespace and detect end of line.
122        start = skip_whitespace(start);
123        if (!*start || *start=='#') {
124            if (ENABLE_BBSH_JOBCTL) line->cmdlinelen = start-cmdline;
125            return 0;
126        }
127
128        // Allocate next command structure if necessary
129        if (!*cmd) *cmd = xzalloc(sizeof(struct command)+8*sizeof(char *));
130
131        // Parse next argument and add the results to argv[]
132        end = parse_word(start, cmd);
133
134        // If we hit the end of this command, how did it end?
135        if (!end) {
136            if (ENABLE_BBSH_PIPES && *start) {
137                if (*start==';') {
138                    start++;
139                    break;
140                }
141                // handle | & < > >> << || &&
142            }
143            break;
144        }
145        start = end;
146    }
147
148    if (ENABLE_BBSH_JOBCTL) line->cmdlinelen = start-cmdline;
149
150    return start;
151}
152
153// Execute the commands in a pipeline
154static int run_pipeline(struct pipeline *line)
155{
156    struct command *cmd = line->cmd;
157    if (!cmd || !cmd->argc) return 0;
158
159    // Handle local commands.  This is totally fake and plastic.
160    if (cmd->argc==2 && !strcmp(cmd->argv[0],"cd"))
161        chdir(cmd->argv[1]);
162    else if (!strcmp(cmd->argv[0],"exit"))
163        exit(cmd->argc>1 ? atoi(cmd->argv[1]) : 0);
164    else {
165        int status;
166        pid_t pid=fork();
167        if (!pid) {
168            run_applet_and_exit(cmd->argv[0],cmd->argc,cmd->argv);
169            execvp(cmd->argv[0],cmd->argv);
170            printf("No %s",cmd->argv[0]);
171            exit(1);
172        } else waitpid(pid, &status, 0);
173    }
174
175    return 0;
176}
177
178static void free_cmd(void *data)
179{
180    struct command *cmd=(struct command *)data;
181
182    while (cmd->argc) free(cmd->argv[--cmd->argc]);
183}
184
185
186static void handle(char *command)
187{
188    struct pipeline line;
189    char *start = command;
190
191    for (;;) {
192        memset(&line,0,sizeof(struct pipeline));
193        start = parse_pipeline(start, &line);
194        if (!line.cmd) break;
195
196        run_pipeline(&line);
197        free_list(line.cmd, free_cmd);
198    }
199}
200
201int bbsh_main(int argc, char **argv);
202int bbsh_main(int argc, char **argv)
203{
204    char *command=NULL;
205    FILE *f;
206
207    getopt32(argv, "c:", &command);
208
209    f = argv[optind] ? xfopen(argv[optind],"r") : NULL;
210    if (command) handle(command);
211    else {
212        unsigned cmdlen=0;
213        for (;;) {
214            if (!f) putchar('$');
215            if (1 > getline(&command, &cmdlen,f ? : stdin)) break;
216
217            handle(command);
218        }
219        if (ENABLE_FEATURE_CLEAN_UP) free(command);
220    }
221
222    return 1;
223}
Note: See TracBrowser for help on using the repository browser.