lash.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * lash -- the BusyBox Lame-Ass SHell
   4  *
   5  * Copyright (C) 1999,2000,2001 by Lineo, inc.
   6  * Written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>
   7  *
   8  * Based in part on ladsh.c by Michael K. Johnson and Erik W. Troan, which is
   9  * under the following liberal license: "We have placed this source code in the
  10  * public domain. Use it in any project, free or commercial."
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  20  * General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  25  *
  26  */
  27
  28 /* The parsing engine of this program is officially at a dead-end.
  29  * Future work in that direction should move to the work posted
  30  * at http://doolittle.faludi.com/~larry/parser.html .
  31  * A start on the integration of that work with the rest of sh.c
  32  * is at http://codepoet.org/sh.c .
  33  */
  34 //
  35 //This works pretty well now, and is now on by default.
  36 #define BB_FEATURE_SH_ENVIRONMENT
  37 //
  38 //Backtick support has some problems, use at your own risk!
  39 //#define BB_FEATURE_SH_BACKTICKS
  40 //
  41 //If, then, else, etc. support..  This should now behave basically
  42 //like any other Bourne shell...
  43 #define BB_FEATURE_SH_IF_EXPRESSIONS
  44 //
  45 /* This is currently a little broken... */
  46 //#define HANDLE_CONTINUATION_CHARS
  47 //
  48 //For debugging/development on the shell only...
  49 //#define DEBUG_SHELL
  50
  51
  52 #include <stdio.h>
  53 #include <stdlib.h>
  54 #include <ctype.h>
  55 #include <errno.h>
  56 #include <fcntl.h>
  57 #include <signal.h>
  58 #include <string.h>
  59 #include <sys/ioctl.h>
  60 #include <sys/wait.h>
  61 #include <unistd.h>
  62 #include <getopt.h>
  63
  64 #undef __GLIBC__
  65 #undef __UCLIBC__
  66
  67 #if ( (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1) ) || defined (__UCLIBC__)
  68 #include <wordexp.h>
  69 #define expand_t        wordexp_t
  70 #undef BB_FEATURE_SH_BACKTICKS
  71 #else
  72 #include <glob.h>
  73 #define expand_t        glob_t
  74 #endif
  75 #include "busybox.h"
  76 #include "cmdedit.h"
  77
  78
  79 static const int MAX_LINE = 256;        /* size of input buffer for cwd data */
  80 static const int MAX_READ = 128;        /* size of input buffer for `read' builtin */
  81 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
  82
  83
  84 enum redir_type { REDIRECT_INPUT, REDIRECT_OVERWRITE,
  85         REDIRECT_APPEND
  86 };
  87
  88 static const unsigned int DEFAULT_CONTEXT=0x1;
  89 static const unsigned int IF_TRUE_CONTEXT=0x2;
  90 static const unsigned int IF_FALSE_CONTEXT=0x4;
  91 static const unsigned int THEN_EXP_CONTEXT=0x8;
  92 static const unsigned int ELSE_EXP_CONTEXT=0x10;
  93
  94
  95 struct jobset {
  96         struct job *head;                       /* head of list of running jobs */
  97         struct job *fg;                         /* current foreground job */
  98 };
  99
 100 struct redir_struct {
 101         enum redir_type type;   /* type of redirection */
 102         int fd;                                         /* file descriptor being redirected */
 103         char *filename;                         /* file to redirect fd to */
 104 };
 105
 106 struct child_prog {
 107         pid_t pid;                                      /* 0 if exited */
 108         char **argv;                            /* program name and arguments */
 109         int num_redirects;                      /* elements in redirection array */
 110         struct redir_struct *redirects; /* I/O redirects */
 111         int is_stopped;                         /* is the program currently running? */
 112         struct job *family;                     /* pointer back to the child's parent job */
 113 };
 114
 115 struct job {
 116         int jobid;                                      /* job number */
 117         int num_progs;                          /* total number of programs in job */
 118         int running_progs;                      /* number of programs running */
 119         char *text;                                     /* name of job */
 120         char *cmdbuf;                           /* buffer various argv's point into */
 121         pid_t pgrp;                                     /* process group ID for the job */
 122         struct child_prog *progs;       /* array of programs in job */
 123         struct job *next;                       /* to track background commands */
 124         int stopped_progs;                      /* number of programs alive, but stopped */
 125         unsigned int job_context;       /* bitmask defining current context */
 126         struct jobset *job_list;
 127 };
 128
 129 struct built_in_command {
 130         char *cmd;                                      /* name */
 131         char *descr;                            /* description */
 132         int (*function) (struct child_prog *);  /* function ptr */
 133 };
 134
 135 struct close_me {
 136         int fd;
 137         struct close_me *next;
 138 };
 139
 140 /* function prototypes for builtins */
 141 static int builtin_cd(struct child_prog *cmd);
 142 static int builtin_env(struct child_prog *dummy);
 143 static int builtin_exec(struct child_prog *cmd);
 144 static int builtin_exit(struct child_prog *cmd);
 145 static int builtin_fg_bg(struct child_prog *cmd);
 146 static int builtin_help(struct child_prog *cmd);
 147 static int builtin_jobs(struct child_prog *dummy);
 148 static int builtin_pwd(struct child_prog *dummy);
 149 static int builtin_export(struct child_prog *cmd);
 150 static int builtin_source(struct child_prog *cmd);
 151 static int builtin_unset(struct child_prog *cmd);
 152 static int builtin_read(struct child_prog *cmd);
 153 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
 154 static int builtin_if(struct child_prog *cmd);
 155 static int builtin_then(struct child_prog *cmd);
 156 static int builtin_else(struct child_prog *cmd);
 157 static int builtin_fi(struct child_prog *cmd);
 158 /* function prototypes for shell stuff */
 159 static int run_command_predicate(char *cmd);
 160 #endif
 161
 162
 163 /* function prototypes for shell stuff */
 164 static void mark_open(int fd);
 165 static void mark_closed(int fd);
 166 static void close_all(void);
 167 static void checkjobs(struct jobset *job_list);
 168 static int get_command(FILE * source, char *command);
 169 static int parse_command(char **command_ptr, struct job *job, int *inbg);
 170 static int run_command(struct job *newjob, int inbg, int outpipe[2]);
 171 static int pseudo_exec(struct child_prog *cmd) __attribute__ ((noreturn));
 172 static int busy_loop(FILE * input);
 173
 174
 175 /* Table of built-in functions (these are non-forking builtins, meaning they
 176  * can change global variables in the parent shell process but they will not
 177  * work with pipes and redirects; 'unset foo | whatever' will not work) */
 178 static struct built_in_command bltins[] = {
 179         {"bg", "Resume a job in the background", builtin_fg_bg},
 180         {"cd", "Change working directory", builtin_cd},
 181         {"exec", "Exec command, replacing this shell with the exec'd process", builtin_exec},
 182         {"exit", "Exit from shell()", builtin_exit},
 183         {"fg", "Bring job into the foreground", builtin_fg_bg},
 184         {"jobs", "Lists the active jobs", builtin_jobs},
 185         {"export", "Set environment variable", builtin_export},
 186         {"unset", "Unset environment variable", builtin_unset},
 187         {"read", "Input environment variable", builtin_read},
 188         {".", "Source-in and run commands in a file", builtin_source},
 189         /* to do: add ulimit */
 190 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
 191         {"if", NULL, builtin_if},
 192         {"then", NULL, builtin_then},
 193         {"else", NULL, builtin_else},
 194         {"fi", NULL, builtin_fi},
 195 #endif
 196         {NULL, NULL, NULL}
 197 };
 198
 199 /* Table of forking built-in functions (things that fork cannot change global
 200  * variables in the parent process, such as the current working directory) */
 201 static struct built_in_command bltins_forking[] = {
 202         {"env", "Print all environment variables", builtin_env},
 203         {"pwd", "Print current directory", builtin_pwd},
 204         {"help", "List shell built-in commands", builtin_help},
 205         {NULL, NULL, NULL}
 206 };
 207
 208
 209 /* Variables we export */
 210 unsigned int shell_context;  /* Used in cmdedit.c to reset the
 211                                                                 context when someone hits ^C */
 212
 213
 214 /* Globals that are static to this file */
 215 static char *cwd;
 216 static char *local_pending_command = NULL;
 217 static struct jobset job_list = { NULL, NULL };
 218 static int argc;
 219 static char **argv;
 220 static struct close_me *close_me_head;
 221 #ifdef BB_FEATURE_SH_ENVIRONMENT
 222 static int last_bg_pid;
 223 static int last_return_code;
 224 static int show_x_trace;
 225 #endif
 226 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
 227 static char syntax_err[]="syntax error near unexpected token";
 228 #endif
 229
 230 #ifdef DEBUG_SHELL
 231 static inline void debug_printf(const char *format, ...)
 232 {
 233         va_list args;
 234         va_start(args, format);
 235         vfprintf(stderr, format, args);
 236         va_end(args);
 237 }
 238 #else
 239 static inline void debug_printf(const char *format, ...) { }
 240 #endif
 241
 242 /*
 243         Most builtins need access to the struct child_prog that has
 244         their arguments, previously coded as cmd->progs[0].  That coding
 245         can exhibit a bug, if the builtin is not the first command in
 246         a pipeline: "echo foo | exec sort" will attempt to exec foo.
 247
 248 builtin   previous use      notes
 249 ------ -----------------  ---------
 250 cd      cmd->progs[0]
 251 env     0
 252 exec    cmd->progs[0]  squashed bug: didn't look for applets or forking builtins
 253 exit    cmd->progs[0]
 254 fg_bg   cmd->progs[0], job_list->head, job_list->fg
 255 help    0
 256 jobs    job_list->head
 257 pwd     0
 258 export  cmd->progs[0]  passes cmd, job_list to builtin_env(), which ignores them
 259 source  cmd->progs[0]
 260 unset   cmd->progs[0]
 261 read    cmd->progs[0]
 262 if      cmd->job_context,  cmd->text
 263 then    cmd->job_context,  cmd->text
 264 else    cmd->job_context,  cmd->text
 265 fi      cmd->job_context
 266
 267 The use of cmd->text by if/then/else/fi is hopelessly hacky.
 268 Would it work to increment cmd->progs[0]->argv and recurse,
 269 somewhat like builtin_exec does?
 270
 271 I added "struct job *family;" to struct child_prog,
 272 and switched API to builtin_foo(struct child_prog *child);
 273 So   cmd->text        becomes  child->family->text
 274      cmd->job_context  becomes  child->family->job_context
 275      cmd->progs[0]    becomes  *child
 276      job_list          becomes  child->family->job_list
 277  */
 278
 279 /* built-in 'cd <path>' handler */
 280 static int builtin_cd(struct child_prog *child)
 281 {
 282         char *newdir;
 283
 284         if (child->argv[1] == NULL)
 285                 newdir = getenv("HOME");
 286         else
 287                 newdir = child->argv[1];
 288         if (chdir(newdir)) {
 289                 printf("cd: %s: %s\n", newdir, strerror(errno));
 290                 return EXIT_FAILURE;
 291         }
 292         getcwd(cwd, sizeof(char)*MAX_LINE);
 293
 294         return EXIT_SUCCESS;
 295 }
 296
 297 /* built-in 'env' handler */
 298 static int builtin_env(struct child_prog *dummy)
 299 {
 300         char **e;
 301
 302         for (e = environ; *e; e++) {
 303                 printf( "%s\n", *e);
 304         }
 305         return (0);
 306 }
 307
 308 /* built-in 'exec' handler */
 309 static int builtin_exec(struct child_prog *child)
 310 {
 311         if (child->argv[1] == NULL)
 312                 return EXIT_SUCCESS;   /* Really? */
 313         child->argv++;
 314         close_all();
 315         pseudo_exec(child);
 316         /* never returns */
 317 }
 318
 319 /* built-in 'exit' handler */
 320 static int builtin_exit(struct child_prog *child)
 321 {
 322         if (child->argv[1] == NULL)
 323                 exit(EXIT_SUCCESS);
 324
 325         exit (atoi(child->argv[1]));
 326 }
 327
 328 /* built-in 'fg' and 'bg' handler */
 329 static int builtin_fg_bg(struct child_prog *child)
 330 {
 331         int i, jobNum;
 332         struct job *job=NULL;
 333
 334         if (!child->argv[1] || child->argv[2]) {
 335                 error_msg("%s: exactly one argument is expected",
 336                                 child->argv[0]);
 337                 return EXIT_FAILURE;
 338         }
 339
 340         if (sscanf(child->argv[1], "%%%d", &jobNum) != 1) {
 341                 error_msg("%s: bad argument '%s'",
 342                                 child->argv[0], child->argv[1]);
 343                 return EXIT_FAILURE;
 344         }
 345
 346         for (job = child->family->job_list->head; job; job = job->next) {
 347                 if (job->jobid == jobNum) {
 348                         break;
 349                 }
 350         }
 351
 352         if (!job) {
 353                 error_msg("%s: unknown job %d",
 354                                 child->argv[0], jobNum);
 355                 return EXIT_FAILURE;
 356         }
 357
 358         if (*child->argv[0] == 'f') {
 359                 /* Make this job the foreground job */
 360                 /* suppress messages when run from /linuxrc mag@sysgo.de */
 361                 if (tcsetpgrp(0, job->pgrp) && errno != ENOTTY)
 362                         perror_msg("tcsetpgrp");
 363                 child->family->job_list->fg = job;
 364         }
 365
 366         /* Restart the processes in the job */
 367         for (i = 0; i < job->num_progs; i++)
 368                 job->progs[i].is_stopped = 0;
 369
 370         kill(-job->pgrp, SIGCONT);
 371
 372         job->stopped_progs = 0;
 373
 374         return EXIT_SUCCESS;
 375 }
 376
 377 /* built-in 'help' handler */
 378 static int builtin_help(struct child_prog *dummy)
 379 {
 380         struct built_in_command *x;
 381
 382         printf("\nBuilt-in commands:\n");
 383         printf("-------------------\n");
 384         for (x = bltins; x->cmd; x++) {
 385                 if (x->descr==NULL)
 386                         continue;
 387                 printf("%s\t%s\n", x->cmd, x->descr);
 388         }
 389         for (x = bltins_forking; x->cmd; x++) {
 390                 if (x->descr==NULL)
 391                         continue;
 392                 printf("%s\t%s\n", x->cmd, x->descr);
 393         }
 394         printf("\n\n");
 395         return EXIT_SUCCESS;
 396 }
 397
 398 /* built-in 'jobs' handler */
 399 static int builtin_jobs(struct child_prog *child)
 400 {
 401         struct job *job;
 402         char *status_string;
 403
 404         for (job = child->family->job_list->head; job; job = job->next) {
 405                 if (job->running_progs == job->stopped_progs)
 406                         status_string = "Stopped";
 407                 else
 408                         status_string = "Running";
 409
 410                 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->text);
 411         }
 412         return EXIT_SUCCESS;
 413 }
 414
 415
 416 /* built-in 'pwd' handler */
 417 static int builtin_pwd(struct child_prog *dummy)
 418 {
 419         getcwd(cwd, MAX_LINE);
 420         printf( "%s\n", cwd);
 421         return EXIT_SUCCESS;
 422 }
 423
 424 /* built-in 'export VAR=value' handler */
 425 static int builtin_export(struct child_prog *child)
 426 {
 427         int res;
 428
 429         if (child->argv[1] == NULL) {
 430                 return (builtin_env(child));
 431         }
 432         res = putenv(child->argv[1]);
 433         if (res)
 434                 fprintf(stderr, "export: %s\n", strerror(errno));
 435         return (res);
 436 }
 437
 438 /* built-in 'read VAR' handler */
 439 static int builtin_read(struct child_prog *child)
 440 {
 441         int res = 0, len, newlen;
 442         char *s;
 443         char string[MAX_READ];
 444
 445         if (child->argv[1]) {
 446                 /* argument (VAR) given: put "VAR=" into buffer */
 447                 strcpy(string, child->argv[1]);
 448                 len = strlen(string);
 449                 string[len++] = '=';
 450                 string[len]   = '\0';
 451                 fgets(&string[len], sizeof(string) - len, stdin);       /* read string */
 452                 newlen = strlen(string);
 453                 if(newlen > len)
 454                         string[--newlen] = '\0';        /* chomp trailing newline */
 455                 /*
 456                 ** string should now contain "VAR=<value>"
 457                 ** copy it (putenv() won't do that, so we must make sure
 458                 ** the string resides in a static buffer!)
 459                 */
 460                 res = -1;
 461                 if((s = strdup(string)))
 462                         res = putenv(s);
 463                 if (res)
 464                         fprintf(stderr, "read: %s\n", strerror(errno));
 465         }
 466         else
 467                 fgets(string, sizeof(string), stdin);
 468
 469         return (res);
 470 }
 471
 472 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
 473 /* Built-in handler for 'if' commands */
 474 static int builtin_if(struct child_prog *child)
 475 {
 476         struct job *cmd = child->family;
 477         int status;
 478         char* charptr1=cmd->text+3; /* skip over the leading 'if ' */
 479
 480         /* Now run the 'if' command */
 481         debug_printf( "job=%p entering builtin_if ('%s')-- context=%d\n", cmd, charptr1, cmd->job_context);
 482         status = run_command_predicate(charptr1);
 483         debug_printf( "if test returned ");
 484         if (status == 0) {
 485                 debug_printf( "TRUE\n");
 486                 cmd->job_context |= IF_TRUE_CONTEXT;
 487         } else {
 488                 debug_printf( "FALSE\n");
 489                 cmd->job_context |= IF_FALSE_CONTEXT;
 490         }
 491         debug_printf("job=%p builtin_if set job context to %x\n", cmd, cmd->job_context);
 492         shell_context++;
 493
 494         return status;
 495 }
 496
 497 /* Built-in handler for 'then' (part of the 'if' command) */
 498 static int builtin_then(struct child_prog *child)
 499 {
 500         struct job *cmd = child->family;
 501         char* charptr1=cmd->text+5; /* skip over the leading 'then ' */
 502
 503         debug_printf( "job=%p entering builtin_then ('%s')-- context=%d\n", cmd, charptr1, cmd->job_context);
 504         if (! (cmd->job_context & (IF_TRUE_CONTEXT|IF_FALSE_CONTEXT))) {
 505                 shell_context = 0; /* Reset the shell's context on an error */
 506                 error_msg("%s `then'", syntax_err);
 507                 return EXIT_FAILURE;
 508         }
 509
 510         cmd->job_context |= THEN_EXP_CONTEXT;
 511         debug_printf("job=%p builtin_then set job context to %x\n", cmd, cmd->job_context);
 512
 513         /* If the if result was FALSE, skip the 'then' stuff */
 514         if (cmd->job_context & IF_FALSE_CONTEXT) {
 515                 return EXIT_SUCCESS;
 516         }
 517
 518         /* Seems the if result was TRUE, so run the 'then' command */
 519         debug_printf( "'then' now running '%s'\n", charptr1);
 520
 521         return(run_command_predicate(charptr1));
 522 }
 523
 524 /* Built-in handler for 'else' (part of the 'if' command) */
 525 static int builtin_else(struct child_prog *child)
 526 {
 527         struct job *cmd = child->family;
 528         char* charptr1=cmd->text+5; /* skip over the leading 'else ' */
 529
 530         debug_printf( "job=%p entering builtin_else ('%s')-- context=%d\n", cmd, charptr1, cmd->job_context);
 531
 532         if (! (cmd->job_context & THEN_EXP_CONTEXT)) {
 533                 shell_context = 0; /* Reset the shell's context on an error */
 534                 error_msg("%s `else'", syntax_err);
 535                 return EXIT_FAILURE;
 536         }
 537         /* If the if result was TRUE, skip the 'else' stuff */
 538         if (cmd->job_context & IF_TRUE_CONTEXT) {
 539                 return EXIT_SUCCESS;
 540         }
 541
 542         cmd->job_context |= ELSE_EXP_CONTEXT;
 543         debug_printf("job=%p builtin_else set job context to %x\n", cmd, cmd->job_context);
 544
 545         /* Now run the 'else' command */
 546         debug_printf( "'else' now running '%s'\n", charptr1);
 547         return(run_command_predicate(charptr1));
 548 }
 549
 550 /* Built-in handler for 'fi' (part of the 'if' command) */
 551 static int builtin_fi(struct child_prog *child)
 552 {
 553         struct job *cmd = child->family;
 554         debug_printf( "job=%p entering builtin_fi ('%s')-- context=%d\n", cmd, "", cmd->job_context);
 555         if (! (cmd->job_context & (IF_TRUE_CONTEXT|IF_FALSE_CONTEXT))) {
 556                 shell_context = 0; /* Reset the shell's context on an error */
 557                 error_msg("%s `fi'", syntax_err);
 558                 return EXIT_FAILURE;
 559         }
 560         /* Clear out the if and then context bits */
 561         cmd->job_context &= ~(IF_TRUE_CONTEXT|IF_FALSE_CONTEXT|THEN_EXP_CONTEXT|ELSE_EXP_CONTEXT);
 562         debug_printf("job=%p builtin_fi set job context to %x\n", cmd, cmd->job_context);
 563         shell_context--;
 564         return EXIT_SUCCESS;
 565 }
 566 #endif
 567
 568 /* Built-in '.' handler (read-in and execute commands from file) */
 569 static int builtin_source(struct child_prog *child)
 570 {
 571         FILE *input;
 572         int status;
 573         int fd;
 574
 575         if (child->argv[1] == NULL)
 576                 return EXIT_FAILURE;
 577
 578         input = fopen(child->argv[1], "r");
 579         if (!input) {
 580                 printf( "Couldn't open file '%s'\n", child->argv[1]);
 581                 return EXIT_FAILURE;
 582         }
 583
 584         fd=fileno(input);
 585         mark_open(fd);
 586         /* Now run the file */
 587         status = busy_loop(input);
 588         fclose(input);
 589         mark_closed(fd);
 590         return (status);
 591 }
 592
 593 /* built-in 'unset VAR' handler */
 594 static int builtin_unset(struct child_prog *child)
 595 {
 596         if (child->argv[1] == NULL) {
 597                 printf( "unset: parameter required.\n");
 598                 return EXIT_FAILURE;
 599         }
 600         unsetenv(child->argv[1]);
 601         return EXIT_SUCCESS;
 602 }
 603
 604 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
 605 /* currently used by if/then/else.
 606  *
 607  * Reparsing the command line for this purpose is gross,
 608  * incorrect, and fundamentally unfixable; in particular,
 609  * think about what happens with command substitution.
 610  * We really need to pull out the run, wait, return status
 611  * functionality out of busy_loop so we can child->argv++
 612  * and use that, without going back through parse_command.
 613  */
 614 static int run_command_predicate(char *cmd)
 615 {
 616         int n=strlen(cmd);
 617         local_pending_command = xmalloc(n+1);
 618         strncpy(local_pending_command, cmd, n);
 619         local_pending_command[n]='\0';
 620         return( busy_loop(NULL));
 621 }
 622 #endif
 623
 624 static void mark_open(int fd)
 625 {
 626         struct close_me *new = xmalloc(sizeof(struct close_me));
 627         new->fd = fd;
 628         new->next = close_me_head;
 629         close_me_head = new;
 630 }
 631
 632 static void mark_closed(int fd)
 633 {
 634         struct close_me *tmp;
 635         if (close_me_head == NULL || close_me_head->fd != fd)
 636                 error_msg_and_die("corrupt close_me");
 637         tmp = close_me_head;
 638         close_me_head = close_me_head->next;
 639         free(tmp);
 640 }
 641
 642 static void close_all()
 643 {
 644         struct close_me *c, *tmp;
 645         for (c=close_me_head; c; c=tmp) {
 646                 close(c->fd);
 647                 tmp=c->next;
 648                 free(c);
 649         }
 650         close_me_head = NULL;
 651 }
 652
 653
 654 /* free up all memory from a job */
 655 static void free_job(struct job *cmd)
 656 {
 657         int i;
 658
 659         for (i = 0; i < cmd->num_progs; i++) {
 660                 free(cmd->progs[i].argv);
 661                 if (cmd->progs[i].redirects)
 662                         free(cmd->progs[i].redirects);
 663         }
 664         free(cmd->progs);
 665         if (cmd->text)
 666                 free(cmd->text);
 667         free(cmd->cmdbuf);
 668         memset(cmd, 0, sizeof(struct job));
 669 }
 670
 671 /* remove a job from the job_list */
 672 static void remove_job(struct jobset *job_list, struct job *job)
 673 {
 674         struct job *prevjob;
 675
 676         free_job(job);
 677         if (job == job_list->head) {
 678                 job_list->head = job->next;
 679         } else {
 680                 prevjob = job_list->head;
 681                 while (prevjob->next != job)
 682                         prevjob = prevjob->next;
 683                 prevjob->next = job->next;
 684         }
 685
 686         free(job);
 687 }
 688
 689 /* Checks to see if any background processes have exited -- if they
 690    have, figure out why and see if a job has completed */
 691 static void checkjobs(struct jobset *job_list)
 692 {
 693         struct job *job;
 694         pid_t childpid;
 695         int status;
 696         int prognum = 0;
 697
 698         while ((childpid = waitpid(-1, &status, WNOHANG | WUNTRACED)) > 0) {
 699                 for (job = job_list->head; job; job = job->next) {
 700                         prognum = 0;
 701                         while (prognum < job->num_progs &&
 702                                    job->progs[prognum].pid != childpid) prognum++;
 703                         if (prognum < job->num_progs)
 704                                 break;
 705                 }
 706
 707                 /* This happens on backticked commands */
 708                 if(job==NULL)
 709                         return;
 710
 711                 if (WIFEXITED(status) || WIFSIGNALED(status)) {
 712                         /* child exited */
 713                         job->running_progs--;
 714                         job->progs[prognum].pid = 0;
 715
 716                         if (!job->running_progs) {
 717                                 printf(JOB_STATUS_FORMAT, job->jobid, "Done", job->text);
 718                                 remove_job(job_list, job);
 719                         }
 720                 } else {
 721                         /* child stopped */
 722                         job->stopped_progs++;
 723                         job->progs[prognum].is_stopped = 1;
 724
 725                         if (job->stopped_progs == job->num_progs) {
 726                                 printf(JOB_STATUS_FORMAT, job->jobid, "Stopped",
 727                                            job->text);
 728                         }
 729                 }
 730         }
 731
 732         if (childpid == -1 && errno != ECHILD)
 733                 perror_msg("waitpid");
 734 }
 735
 736 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
 737  * and stderr if they are redirected. */
 738 static int setup_redirects(struct child_prog *prog, int squirrel[])
 739 {
 740         int i;
 741         int openfd;
 742         int mode = O_RDONLY;
 743         struct redir_struct *redir = prog->redirects;
 744
 745         for (i = 0; i < prog->num_redirects; i++, redir++) {
 746                 switch (redir->type) {
 747                 case REDIRECT_INPUT:
 748                         mode = O_RDONLY;
 749                         break;
 750                 case REDIRECT_OVERWRITE:
 751                         mode = O_WRONLY | O_CREAT | O_TRUNC;
 752                         break;
 753                 case REDIRECT_APPEND:
 754                         mode = O_WRONLY | O_CREAT | O_APPEND;
 755                         break;
 756                 }
 757
 758                 openfd = open(redir->filename, mode, 0666);
 759                 if (openfd < 0) {
 760                         /* this could get lost if stderr has been redirected, but
 761                            bash and ash both lose it as well (though zsh doesn't!) */
 762                         error_msg("error opening %s: %s", redir->filename,
 763                                         strerror(errno));
 764                         return 1;
 765                 }
 766
 767                 if (openfd != redir->fd) {
 768                         if (squirrel && redir->fd < 3) {
 769                                 squirrel[redir->fd] = dup(redir->fd);
 770                         }
 771                         dup2(openfd, redir->fd);
 772                         close(openfd);
 773                 }
 774         }
 775
 776         return 0;
 777 }
 778
 779 static void restore_redirects(int squirrel[])
 780 {
 781         int i, fd;
 782         for (i=0; i<3; i++) {
 783                 fd = squirrel[i];
 784                 if (fd != -1) {
 785                         /* No error checking.  I sure wouldn't know what
 786                          * to do with an error if I found one! */
 787                         dup2(fd, i);
 788                         close(fd);
 789                 }
 790         }
 791 }
 792
 793 #if defined(BB_FEATURE_SH_SIMPLE_PROMPT)
 794 static char* setup_prompt_string(int state)
 795 {
 796        char prompt_str[BUFSIZ];
 797
 798        /* Set up the prompt */
 799        if (state == 0) {
 800                /* simple prompt */
 801                sprintf(prompt_str, "%s %s", cwd, ( geteuid() != 0 ) ?  "$ ":"# ");
 802        } else {
 803                strcpy(prompt_str,"> ");
 804        }
 805
 806        return(strdup(prompt_str));  /* Must free this memory */
 807 }
 808
 809 #else
 810
 811 static char* setup_prompt_string(int state)
 812 {
 813         char user[9],buf[255],*s;
 814         char prompt[3];
 815         char prompt_str[BUFSIZ];
 816
 817         /* Set up the prompt */
 818         if (state == 0) {
 819                 /* get User Name and setup prompt */
 820                 strcpy(prompt,( geteuid() != 0 ) ? "$ ":"# ");
 821                 my_getpwuid(user, geteuid());
 822
 823                 /* get HostName */
 824                 gethostname(buf, 255);
 825                 s = strchr(buf, '.');
 826                 if (s) {
 827                         *s = 0;
 828                 }
 829         } else {
 830                 strcpy(prompt,"> ");
 831         }
 832
 833         if (state == 0) {
 834                 snprintf(prompt_str, BUFSIZ-1, "[%s@%s %s]%s", user, buf,
 835                                 get_last_path_component(cwd), prompt);
 836         } else {
 837                 sprintf(prompt_str, "%s", prompt);
 838         }
 839         return(strdup(prompt_str));  /* Must free this memory */
 840 }
 841
 842 #endif
 843
 844 static int get_command(FILE * source, char *command)
 845 {
 846         char *prompt_str;
 847
 848         if (source == NULL) {
 849                 if (local_pending_command) {
 850                         /* a command specified (-c option): return it & mark it done */
 851                         strcpy(command, local_pending_command);
 852                         free(local_pending_command);
 853                         local_pending_command = NULL;
 854                         return 0;
 855                 }
 856                 return 1;
 857         }
 858
 859         if (source == stdin) {
 860                 prompt_str = setup_prompt_string(shell_context);
 861
 862 #ifdef BB_FEATURE_SH_COMMAND_EDITING
 863                 /*
 864                 ** enable command line editing only while a command line
 865                 ** is actually being read; otherwise, we'll end up bequeathing
 866                 ** atexit() handlers and other unwanted stuff to our
 867                 ** child processes (rob@sysgo.de)
 868                 */
 869                 cmdedit_read_input(prompt_str, command);
 870                 cmdedit_terminate();
 871                 free(prompt_str);
 872                 return 0;
 873 #else
 874                 fputs(prompt_str, stdout);
 875                 free(prompt_str);
 876 #endif
 877         }
 878
 879         if (!fgets(command, BUFSIZ - 2, source)) {
 880                 if (source == stdin)
 881                         printf("\n");
 882                 return 1;
 883         }
 884
 885         /* remove trailing newline */
 886         chomp(command);
 887
 888         return 0;
 889 }
 890
 891 #ifdef BB_FEATURE_SH_ENVIRONMENT
 892 static char* itoa(register int i)
 893 {
 894         static char a[7]; /* Max 7 ints */
 895         register char *b = a + sizeof(a) - 1;
 896         int   sign = (i < 0);
 897
 898         if (sign)
 899                 i = -i;
 900         *b = 0;
 901         do
 902         {
 903                 *--b = '0' + (i % 10);
 904                 i /= 10;
 905         }
 906         while (i);
 907         if (sign)
 908                 *--b = '-';
 909         return b;
 910 }
 911 #endif
 912
 913 static int expand_arguments(char *command)
 914 {
 915 #ifdef BB_FEATURE_SH_ENVIRONMENT
 916         expand_t expand_result;
 917         char *src, *dst, *var;
 918         int i=0, length, total_length=0, retval;
 919 #endif
 920
 921         /* get rid of the terminating \n */
 922         chomp(command);
 923
 924 #ifdef BB_FEATURE_SH_ENVIRONMENT
 925
 926
 927 #if ( (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1) ) || defined (__UCLIBC__)
 928         /* This first part uses wordexp() which is a wonderful C lib
 929          * function which expands nearly everything.  */
 930         retval = wordexp (command, &expand_result, 0);
 931         if (retval == WRDE_NOSPACE) {
 932                 /* Mem may have been allocated... */
 933                 wordfree (&expand_result);
 934                 error_msg("out of space during expansion");
 935                 return FALSE;
 936         }
 937         if (retval < 0) {
 938                 /* Some other error.  */
 939                 error_msg("syntax error");
 940                 return FALSE;
 941         }
 942
 943         /* Convert from char** (one word per string) to a simple char*,
 944          * but don't overflow command which is BUFSIZ in length */
 945         *command = '\0';
 946         while (i < expand_result.we_wordc && total_length < BUFSIZ) {
 947                 length=strlen(expand_result.we_wordv[i])+1;
 948                 if (BUFSIZ-total_length-length <= 0) {
 949                         error_msg("out of space during expansion");
 950                         return FALSE;
 951                 }
 952                 strcat(command+total_length, expand_result.we_wordv[i++]);
 953                 strcat(command+total_length, " ");
 954                 total_length+=length;
 955         }
 956         wordfree (&expand_result);
 957 #else
 958
 959         /* Ok.  They don't have glibc and they don't have uClibc.  Chances are
 960          * about 100% they don't have wordexp(), so instead, the best we can do is
 961          * use glob, which is better then nothing, but certainly not perfect */
 962
 963         /* It turns out that glob is very stupid.  We have to feed it
 964          * one word at a time since it can't cope with a full string.
 965          * Here we convert command (char*) into cmd (char**, one word
 966          * per string) */
 967         {
 968
 969                 int flags = GLOB_NOCHECK|GLOB_BRACE|GLOB_TILDE;
 970                 char * tmpcmd;
 971                 /* We need a clean copy, so strsep can mess up the copy while
 972                  * we write stuff into the original in a minute */
 973                 char * cmd = strdup(command);
 974                 for (tmpcmd = cmd; (tmpcmd = strsep(&cmd, " \t")) != NULL;) {
 975                         if (*tmpcmd == '\0')
 976                                 break;
 977                         retval = glob(tmpcmd, flags, NULL, &expand_result);
 978                         /* We can't haveGLOB_APPEND on the first glob call,
 979                          * so put it there now */
 980                         if (! (flags & GLOB_APPEND) )
 981                                 flags |= GLOB_APPEND;
 982
 983                         if (retval == GLOB_NOSPACE) {
 984                                 /* Mem may have been allocated... */
 985                                 globfree (&expand_result);
 986                                 error_msg("out of space during expansion");
 987                                 return FALSE;
 988                         }
 989                         if (retval != 0 && retval != GLOB_NOMATCH) {
 990                                 /* Some other error.  */
 991                                 error_msg("syntax error");
 992                                 return FALSE;
 993                         }
 994
 995                         /* Convert from char** (one word per string) to a simple char*,
 996                          * but don't overflow command which is BUFSIZ in length */
 997                         if ( expand_result.gl_pathc > 1) {
 998                                 *command = '\0';
 999                                 while (i < expand_result.gl_pathc && total_length < BUFSIZ) {
1000                                         length=strlen(expand_result.gl_pathv[i])+1;
1001                                         if (BUFSIZ-total_length-length <= 0) {
1002                                                 error_msg("out of space during expansion");
1003                                                 return FALSE;
1004                                         }
1005                                         strcat(command+total_length, expand_result.gl_pathv[i++]);
1006                                         strcat(command+total_length, " ");
1007                                         total_length+=length;
1008                                 }
1009                         }
1010                 }
1011
1012                 free(cmd);
1013                 globfree (&expand_result);
1014         }
1015
1016 #endif
1017
1018         /* FIXME -- this routine (which is only used when folks
1019          * don't have a C library with wordexp) needs a bit of help
1020          * to handle things like 'echo $PATH$0' */
1021
1022         /* Now do the shell variable substitutions which
1023          * wordexp can't do for us, namely $? and $! */
1024         src = command;
1025         while((dst = strchr(src,'$')) != NULL){
1026                 /* Ok -- got a $ -- now clean up any trailing mess */
1027                 trim(dst);
1028                 if (!(var = getenv(dst + 1))) {
1029                         switch(*(dst+1)) {
1030                                 case '?':
1031                                         var = itoa(last_return_code);
1032                                         break;
1033                                 case '!':
1034                                         if (last_bg_pid==-1)
1035                                                 *(var)='\0';
1036                                         else
1037                                                 var = itoa(last_bg_pid);
1038                                         break;
1039                                 /* Everything else like $$, $#, $[0-9], etc should all be
1040                                  * expanded by wordexp(), so we can in theory skip that stuff
1041                                  * here, but just to be on the safe side (i.e. since uClibc
1042                                  * wordexp doesn't do this stuff yet), lets leave it in for
1043                                  * now. */
1044                                 case '$':
1045                                         var = itoa(getpid());
1046                                         break;
1047                                 case '#':
1048                                         var = itoa(argc-1);
1049                                         break;
1050                                 case '0':case '1':case '2':case '3':case '4':
1051                                 case '5':case '6':case '7':case '8':case '9':
1052                                         {
1053                                                 int index=*(dst + 1)-48;
1054                                                 if (index >= argc) {
1055                                                         var='\0';
1056                                                 } else {
1057                                                         var = argv[index];
1058                                                 }
1059                                         }
1060                                         break;
1061
1062                         }
1063                 }
1064                 if (var) {
1065                         int subst_len = strlen(var);
1066                         char *next_dst;
1067                         if ((next_dst=strpbrk(dst+1, " \t~`!$^&*()=|\\{}[];\"'<>?.")) == NULL) {
1068                                 next_dst = dst;
1069                         }
1070                         src = (char*)xrealloc(src, strlen(src) - strlen(next_dst)+strlen(var)+1);
1071                         /* Move stuff to the end of the string to accommodate filling
1072                          * the created gap with the new stuff */
1073                         memmove(dst+subst_len, next_dst+1, subst_len);
1074                         /* Now copy in the new stuff */
1075                         strncpy(dst, var, subst_len+1);
1076                         src = dst;
1077                         src++;
1078                 } else {
1079                         /* Seems we got an un-expandable variable.  So delete it. */
1080                         char *next_dst;
1081                         if ((next_dst=strpbrk(dst+1, " \t~`!$^&*()=|\\{}[];\"'<>?.")) == NULL) {
1082                                 next_dst=dst+1+strlen(dst);
1083                         }
1084                         /* Move stuff to the end of the string to accommodate filling
1085                          * the created gap with the new stuff */
1086                         memmove(dst, next_dst,  next_dst-dst);
1087                 }
1088         }
1089
1090
1091
1092
1093 #endif
1094         return TRUE;
1095 }
1096
1097 /* Return cmd->num_progs as 0 if no command is present (e.g. an empty
1098    line). If a valid command is found, command_ptr is set to point to
1099    the beginning of the next command (if the original command had more
1100    then one job associated with it) or NULL if no more commands are
1101    present. */
1102 static int parse_command(char **command_ptr, struct job *job, int *inbg)
1103 {
1104         char *command;
1105         char *return_command = NULL;
1106         char *src, *buf, *chptr;
1107         int argc_l = 0;
1108         int done = 0;
1109         int argv_alloced;
1110         int i;
1111         char quote = '\0';
1112         int count;
1113         struct child_prog *prog;
1114
1115         /* skip leading white space */
1116         while (**command_ptr && isspace(**command_ptr))
1117                 (*command_ptr)++;
1118
1119         /* this handles empty lines or leading '#' characters */
1120         if (!**command_ptr || (**command_ptr == '#')) {
1121                 job->num_progs=0;
1122                 return 0;
1123         }
1124
1125         *inbg = 0;
1126         job->num_progs = 1;
1127         job->progs = xmalloc(sizeof(*job->progs));
1128
1129         /* We set the argv elements to point inside of this string. The
1130            memory is freed by free_job(). Allocate twice the original
1131            length in case we need to quote every single character.
1132
1133            Getting clean memory relieves us of the task of NULL
1134            terminating things and makes the rest of this look a bit
1135            cleaner (though it is, admittedly, a tad less efficient) */
1136         job->cmdbuf = command = xcalloc(2*strlen(*command_ptr) + 1, sizeof(char));
1137         job->text = NULL;
1138
1139         prog = job->progs;
1140         prog->num_redirects = 0;
1141         prog->redirects = NULL;
1142         prog->is_stopped = 0;
1143         prog->family = job;
1144
1145         argv_alloced = 5;
1146         prog->argv = xmalloc(sizeof(*prog->argv) * argv_alloced);
1147         prog->argv[0] = job->cmdbuf;
1148
1149         buf = command;
1150         src = *command_ptr;
1151         while (*src && !done) {
1152                 if (quote == *src) {
1153                         quote = '\0';
1154                 } else if (quote) {
1155                         if (*src == '\\') {
1156                                 src++;
1157                                 if (!*src) {
1158                                         error_msg("character expected after \\");
1159                                         free_job(job);
1160                                         return 1;
1161                                 }
1162
1163                                 /* in shell, "\'" should yield \' */
1164                                 if (*src != quote) {
1165                                         *buf++ = '\\';
1166                                         *buf++ = '\\';
1167                                 }
1168                         } else if (*src == '*' || *src == '?' || *src == '[' ||
1169                                            *src == ']') *buf++ = '\\';
1170                         *buf++ = *src;
1171                 } else if (isspace(*src)) {
1172                         if (*prog->argv[argc_l]) {
1173                                 buf++, argc_l++;
1174                                 /* +1 here leaves room for the NULL which ends argv */
1175                                 if ((argc_l + 1) == argv_alloced) {
1176                                         argv_alloced += 5;
1177                                         prog->argv = xrealloc(prog->argv,
1178                                                                                   sizeof(*prog->argv) *
1179                                                                                   argv_alloced);
1180                                 }
1181                                 prog->argv[argc_l] = buf;
1182                         }
1183                 } else
1184                         switch (*src) {
1185                         case '"':
1186                         case '\'':
1187                                 quote = *src;
1188                                 break;
1189
1190                         case '#':                       /* comment */
1191                                 if (*(src-1)== '$')
1192                                         *buf++ = *src;
1193                                 else
1194                                         done = 1;
1195                                 break;
1196
1197                         case '>':                       /* redirects */
1198                         case '<':
1199                                 i = prog->num_redirects++;
1200                                 prog->redirects = xrealloc(prog->redirects,
1201                                                                                           sizeof(*prog->redirects) *
1202                                                                                           (i + 1));
1203
1204                                 prog->redirects[i].fd = -1;
1205                                 if (buf != prog->argv[argc_l]) {
1206                                         /* the stuff before this character may be the file number
1207                                            being redirected */
1208                                         prog->redirects[i].fd =
1209                                                 strtol(prog->argv[argc_l], &chptr, 10);
1210
1211                                         if (*chptr && *prog->argv[argc_l]) {
1212                                                 buf++, argc_l++;
1213                                                 prog->argv[argc_l] = buf;
1214                                         }
1215                                 }
1216
1217                                 if (prog->redirects[i].fd == -1) {
1218                                         if (*src == '>')
1219                                                 prog->redirects[i].fd = 1;
1220                                         else
1221                                                 prog->redirects[i].fd = 0;
1222                                 }
1223
1224                                 if (*src++ == '>') {
1225                                         if (*src == '>')
1226                                                 prog->redirects[i].type =
1227                                                         REDIRECT_APPEND, src++;
1228                                         else
1229                                                 prog->redirects[i].type = REDIRECT_OVERWRITE;
1230                                 } else {
1231                                         prog->redirects[i].type = REDIRECT_INPUT;
1232                                 }
1233
1234                                 /* This isn't POSIX sh compliant. Oh well. */
1235                                 chptr = src;
1236                                 while (isspace(*chptr))
1237                                         chptr++;
1238
1239                                 if (!*chptr) {
1240                                         error_msg("file name expected after %c", *src);
1241                                         free_job(job);
1242                                         job->num_progs=0;
1243                                         return 1;
1244                                 }
1245
1246                                 prog->redirects[i].filename = buf;
1247                                 while (*chptr && !isspace(*chptr))
1248                                         *buf++ = *chptr++;
1249
1250                                 src = chptr - 1;        /* we src++ later */
1251                                 prog->argv[argc_l] = ++buf;
1252                                 break;
1253
1254                         case '|':                       /* pipe */
1255                                 /* finish this command */
1256                                 if (*prog->argv[argc_l])
1257                                         argc_l++;
1258                                 if (!argc_l) {
1259                                         error_msg("empty command in pipe");
1260                                         free_job(job);
1261                                         job->num_progs=0;
1262                                         return 1;
1263                                 }
1264                                 prog->argv[argc_l] = NULL;
1265
1266                                 /* and start the next */
1267                                 job->num_progs++;
1268                                 job->progs = xrealloc(job->progs,
1269                                                                           sizeof(*job->progs) * job->num_progs);
1270                                 prog = job->progs + (job->num_progs - 1);
1271                                 prog->num_redirects = 0;
1272                                 prog->redirects = NULL;
1273                                 prog->is_stopped = 0;
1274                                 prog->family = job;
1275                                 argc_l = 0;
1276
1277                                 argv_alloced = 5;
1278                                 prog->argv = xmalloc(sizeof(*prog->argv) * argv_alloced);
1279                                 prog->argv[0] = ++buf;
1280
1281                                 src++;
1282                                 while (*src && isspace(*src))
1283                                         src++;
1284
1285                                 if (!*src) {
1286                                         error_msg("empty command in pipe");
1287                                         free_job(job);
1288                                         job->num_progs=0;
1289                                         return 1;
1290                                 }
1291                                 src--;                  /* we'll ++ it at the end of the loop */
1292
1293                                 break;
1294
1295                         case '&':                       /* background */
1296                                 *inbg = 1;
1297                         case ';':                       /* multiple commands */
1298                                 done = 1;
1299                                 return_command = *command_ptr + (src - *command_ptr) + 1;
1300                                 break;
1301
1302 #ifdef BB_FEATURE_SH_BACKTICKS
1303                         case '`':
1304                                 /* Exec a backtick-ed command */
1305                                 /* Besides any previous brokenness, I have not
1306                                  * updated backtick handling for close_me support.
1307                                  * I don't know if it needs it or not.  -- LRD */
1308                                 {
1309                                         char* charptr1=NULL, *charptr2;
1310                                         char* ptr=NULL;
1311                                         struct job *newjob;
1312                                         struct jobset njob_list = { NULL, NULL };
1313                                         int pipefd[2];
1314                                         int size;
1315
1316                                         ptr=strchr(++src, '`');
1317                                         if (ptr==NULL) {
1318                                                 fprintf(stderr, "Unmatched '`' in command\n");
1319                                                 free_job(job);
1320                                                 return 1;
1321                                         }
1322
1323                                         /* Make some space to hold just the backticked command */
1324                                         charptr1 = charptr2 = xmalloc(1+ptr-src);
1325                                         memcpy(charptr1, src, ptr-src);
1326                                         charptr1[ptr-src] = '\0';
1327                                         newjob = xmalloc(sizeof(struct job));
1328                                         newjob->job_list = &njob_list;
1329                                         /* Now parse and run the backticked command */
1330                                         if (!parse_command(&charptr1, newjob, inbg)
1331                                                         && newjob->num_progs) {
1332                                                 pipe(pipefd);
1333                                                 run_command(newjob, 0, pipefd);
1334                                         }
1335                                         checkjobs(job->job_list);
1336                                         free_job(newjob);  /* doesn't actually free newjob,
1337                                                              looks like a memory leak */
1338                                         free(charptr2);
1339
1340                                         /* Make a copy of any stuff left over in the command
1341                                          * line after the second backtick */
1342                                         charptr2 = xmalloc(strlen(ptr)+1);
1343                                         memcpy(charptr2, ptr+1, strlen(ptr));
1344
1345
1346                                         /* Copy the output from the backtick-ed command into the
1347                                          * command line, making extra room as needed  */
1348                                         --src;
1349                                         charptr1 = xmalloc(BUFSIZ);
1350                                         while ( (size=full_read(pipefd[0], charptr1, BUFSIZ-1)) >0) {
1351                                                 int newsize=src - *command_ptr + size + 1 + strlen(charptr2);
1352                                                 if (newsize > BUFSIZ) {
1353                                                         *command_ptr=xrealloc(*command_ptr, newsize);
1354                                                 }
1355                                                 memcpy(src, charptr1, size);
1356                                                 src+=size;
1357                                         }
1358                                         free(charptr1);
1359                                         close(pipefd[0]);
1360                                         if (*(src-1)=='\n')
1361                                                 --src;
1362
1363                                         /* Now paste into the *command_ptr all the stuff
1364                                          * leftover after the second backtick */
1365                                         memcpy(src, charptr2, strlen(charptr2)+1);
1366                                         free(charptr2);
1367
1368                                         /* Now recursively call parse_command to deal with the new
1369                                          * and improved version of the command line with the backtick
1370                                          * results expanded in place... */
1371                                         {
1372                                                 struct jobset *jl=job->job_list;
1373                                                 free_job(job);
1374                                                 job->job_list = jl;
1375                                         }
1376                                         return(parse_command(command_ptr, job, inbg));
1377                                 }
1378                                 break;
1379 #endif // BB_FEATURE_SH_BACKTICKS
1380
1381                         case '\\':
1382                                 src++;
1383                                 if (!*src) {
1384 /* This is currently a little broken... */
1385 #ifdef HANDLE_CONTINUATION_CHARS
1386                                         /* They fed us a continuation char, so continue reading stuff
1387                                          * on the next line, then tack that onto the end of the current
1388                                          * command */
1389                                         char *command;
1390                                         int newsize;
1391                                         printf("erik: found a continue char at EOL...\n");
1392                                         command = (char *) xcalloc(BUFSIZ, sizeof(char));
1393                                         if (get_command(input, command)) {
1394                                                 error_msg("character expected after \\");
1395                                                 free(command);
1396                                                 free_job(job);
1397                                                 return 1;
1398                                         }
1399                                         newsize = strlen(*command_ptr) + strlen(command) + 2;
1400                                         if (newsize > BUFSIZ) {
1401                                                 printf("erik: doing realloc\n");
1402                                                 *command_ptr=xrealloc(*command_ptr, newsize);
1403                                         }
1404                                         printf("erik: A: *command_ptr='%s'\n", *command_ptr);
1405                                         memcpy(--src, command, strlen(command));
1406                                         printf("erik: B: *command_ptr='%s'\n", *command_ptr);
1407                                         free(command);
1408                                         break;
1409 #else
1410                                         error_msg("character expected after \\");
1411                                         free(command);
1412                                         free_job(job);
1413                                         return 1;
1414 #endif
1415                                 }
1416                                 if (*src == '*' || *src == '[' || *src == ']'
1417                                         || *src == '?') *buf++ = '\\';
1418                                 /* fallthrough */
1419                         default:
1420                                 *buf++ = *src;
1421                         }
1422
1423                 src++;
1424         }
1425
1426         if (*prog->argv[argc_l]) {
1427                 argc_l++;
1428         }
1429         if (!argc_l) {
1430                 free_job(job);
1431                 return 0;
1432         }
1433         prog->argv[argc_l] = NULL;
1434
1435         if (!return_command) {
1436                 job->text = xmalloc(strlen(*command_ptr) + 1);
1437                 strcpy(job->text, *command_ptr);
1438         } else {
1439                 /* This leaves any trailing spaces, which is a bit sloppy */
1440                 count = return_command - *command_ptr;
1441                 job->text = xmalloc(count + 1);
1442                 strncpy(job->text, *command_ptr, count);
1443                 job->text[count] = '\0';
1444         }
1445
1446         *command_ptr = return_command;
1447
1448         return 0;
1449 }
1450
1451 /* Run the child_prog, no matter what kind of command it uses.
1452  */
1453 static int pseudo_exec(struct child_prog *child)
1454 {
1455         struct built_in_command *x;
1456 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
1457         char *name;
1458 #endif
1459
1460         /* Check if the command matches any of the non-forking builtins.
1461          * Depending on context, this might be redundant.  But it's
1462          * easier to waste a few CPU cycles than it is to figure out
1463          * if this is one of those cases.
1464          */
1465         for (x = bltins; x->cmd; x++) {
1466                 if (strcmp(child->argv[0], x->cmd) == 0 ) {
1467                         exit(x->function(child));
1468                 }
1469         }
1470
1471         /* Check if the command matches any of the forking builtins. */
1472         for (x = bltins_forking; x->cmd; x++) {
1473                 if (strcmp(child->argv[0], x->cmd) == 0) {
1474                         applet_name=x->cmd;
1475                         exit (x->function(child));
1476                 }
1477         }
1478 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
1479         /* Check if the command matches any busybox internal
1480          * commands ("applets") here.  Following discussions from
1481          * November 2000 on busybox@opensource.lineo.com, don't use
1482          * get_last_path_component().  This way explicit (with
1483          * slashes) filenames will never be interpreted as an
1484          * applet, just like with builtins.  This way the user can
1485          * override an applet with an explicit filename reference.
1486          * The only downside to this change is that an explicit
1487          * /bin/foo invocation will fork and exec /bin/foo, even if
1488          * /bin/foo is a symlink to busybox.
1489          */
1490         name = child->argv[0];
1491
1492 #ifdef BB_FEATURE_SH_APPLETS_ALWAYS_WIN
1493         /* If you enable BB_FEATURE_SH_APPLETS_ALWAYS_WIN, then
1494          * if you run /bin/cat, it will use BusyBox cat even if
1495          * /bin/cat exists on the filesystem and is _not_ busybox.
1496          * Some systems want this, others do not.  Choose wisely.  :-)
1497          */
1498         name = get_last_path_component(name);
1499 #endif
1500
1501         {
1502             char** argv=child->argv;
1503             int argc_l;
1504             for(argc_l=0;*argv!=NULL; argv++, argc_l++);
1505             optind = 1;
1506             run_applet_by_name(name, argc_l, child->argv);
1507         }
1508 #endif
1509
1510         execvp(child->argv[0], child->argv);
1511         perror_msg_and_die("%s", child->argv[0]);
1512 }
1513
1514 static void insert_job(struct job *newjob, int inbg)
1515 {
1516         struct job *thejob;
1517         struct jobset *job_list=newjob->job_list;
1518
1519         /* find the ID for thejob to use */
1520         newjob->jobid = 1;
1521         for (thejob = job_list->head; thejob; thejob = thejob->next)
1522                 if (thejob->jobid >= newjob->jobid)
1523                         newjob->jobid = thejob->jobid + 1;
1524
1525         /* add thejob to the list of running jobs */
1526         if (!job_list->head) {
1527                 thejob = job_list->head = xmalloc(sizeof(*thejob));
1528         } else {
1529                 for (thejob = job_list->head; thejob->next; thejob = thejob->next) /* nothing */;
1530                 thejob->next = xmalloc(sizeof(*thejob));
1531                 thejob = thejob->next;
1532         }
1533
1534         *thejob = *newjob;   /* physically copy the struct job */
1535         thejob->next = NULL;
1536         thejob->running_progs = thejob->num_progs;
1537         thejob->stopped_progs = 0;
1538
1539         if (inbg) {
1540                 /* we don't wait for background thejobs to return -- append it
1541                    to the list of backgrounded thejobs and leave it alone */
1542                 printf("[%d] %d\n", thejob->jobid,
1543                            newjob->progs[newjob->num_progs - 1].pid);
1544 #ifdef BB_FEATURE_SH_ENVIRONMENT
1545                 last_bg_pid=newjob->progs[newjob->num_progs - 1].pid;
1546 #endif
1547         } else {
1548                 newjob->job_list->fg = thejob;
1549
1550                 /* move the new process group into the foreground */
1551                 /* suppress messages when run from /linuxrc mag@sysgo.de */
1552                 if (tcsetpgrp(0, newjob->pgrp) && errno != ENOTTY)
1553                         perror_msg("tcsetpgrp");
1554         }
1555 }
1556
1557 static int run_command(struct job *newjob, int inbg, int outpipe[2])
1558 {
1559         /* struct job *thejob; */
1560         int i;
1561         int nextin, nextout;
1562         int pipefds[2];                         /* pipefd[0] is for reading */
1563         struct built_in_command *x;
1564         struct child_prog *child;
1565
1566         nextin = 0, nextout = 1;
1567         for (i = 0; i < newjob->num_progs; i++) {
1568                 child = & (newjob->progs[i]);
1569
1570                 if ((i + 1) < newjob->num_progs) {
1571                         if (pipe(pipefds)<0) perror_msg_and_die("pipe");
1572                         nextout = pipefds[1];
1573                 } else {
1574                         if (outpipe[1]!=-1) {
1575                                 nextout = outpipe[1];
1576                         } else {
1577                                 nextout = 1;
1578                         }
1579                 }
1580
1581 #ifdef BB_FEATURE_SH_ENVIRONMENT
1582                 if (show_x_trace==TRUE) {
1583                         int j;
1584                         fputc('+', stderr);
1585                         for (j = 0; child->argv[j]; j++) {
1586                                 fputc(' ', stderr);
1587                                 fputs(child->argv[j], stderr);
1588                         }
1589                         fputc('\n', stderr);
1590                 }
1591 #endif
1592
1593                 /* Check if the command matches any non-forking builtins,
1594                  * but only if this is a simple command.
1595                  * Non-forking builtins within pipes have to fork anyway,
1596                  * and are handled in pseudo_exec.  "echo foo | read bar"
1597                  * is doomed to failure, and doesn't work on bash, either.
1598                  */
1599                 if (newjob->num_progs == 1) {
1600                         for (x = bltins; x->cmd; x++) {
1601                                 if (strcmp(child->argv[0], x->cmd) == 0 ) {
1602                                         int squirrel[] = {-1, -1, -1};
1603                                         int rcode;
1604                                         setup_redirects(child, squirrel);
1605                                         rcode = x->function(child);
1606                                         restore_redirects(squirrel);
1607                                         return rcode;
1608                                 }
1609                         }
1610                 }
1611
1612                 if (!(child->pid = fork())) {
1613                         signal(SIGTTOU, SIG_DFL);
1614
1615                         close_all();
1616
1617                         if (outpipe[1]!=-1) {
1618                                 close(outpipe[0]);
1619                         }
1620                         if (nextin != 0) {
1621                                 dup2(nextin, 0);
1622                                 close(nextin);
1623                         }
1624
1625                         if (nextout != 1) {
1626                                 dup2(nextout, 1);
1627                                 dup2(nextout, 2);  /* Really? */
1628                                 close(nextout);
1629                                 close(pipefds[0]);
1630                         }
1631
1632                         /* explicit redirects override pipes */
1633                         setup_redirects(child,NULL);
1634
1635                         pseudo_exec(child);
1636                 }
1637                 if (outpipe[1]!=-1) {
1638                         close(outpipe[1]);
1639                 }
1640
1641                 /* put our child in the process group whose leader is the
1642                    first process in this pipe */
1643                 setpgid(child->pid, newjob->progs[0].pid);
1644                 if (nextin != 0)
1645                         close(nextin);
1646                 if (nextout != 1)
1647                         close(nextout);
1648
1649                 /* If there isn't another process, nextin is garbage
1650                    but it doesn't matter */
1651                 nextin = pipefds[0];
1652         }
1653
1654         newjob->pgrp = newjob->progs[0].pid;
1655
1656         insert_job(newjob, inbg);
1657
1658         return 0;
1659 }
1660
1661 static int busy_loop(FILE * input)
1662 {
1663         char *command;
1664         char *next_command = NULL;
1665         struct job newjob;
1666         pid_t  parent_pgrp;
1667         int i;
1668         int inbg;
1669         int status;
1670         newjob.job_list = &job_list;
1671         newjob.job_context = DEFAULT_CONTEXT;
1672
1673         /* save current owner of TTY so we can restore it on exit */
1674         parent_pgrp = tcgetpgrp(0);
1675
1676         command = (char *) xcalloc(BUFSIZ, sizeof(char));
1677
1678         /* don't pay any attention to this signal; it just confuses
1679            things and isn't really meant for shells anyway */
1680         signal(SIGTTOU, SIG_IGN);
1681
1682         while (1) {
1683                 if (!job_list.fg) {
1684                         /* no job is in the foreground */
1685
1686                         /* see if any background processes have exited */
1687                         checkjobs(&job_list);
1688
1689                         if (!next_command) {
1690                                 if (get_command(input, command))
1691                                         break;
1692                                 next_command = command;
1693                         }
1694
1695                         if (expand_arguments(next_command) == FALSE) {
1696                                 free(command);
1697                                 command = (char *) xcalloc(BUFSIZ, sizeof(char));
1698                                 next_command = NULL;
1699                                 continue;
1700                         }
1701
1702                         if (!parse_command(&next_command, &newjob, &inbg) &&
1703                                 newjob.num_progs) {
1704                                 int pipefds[2] = {-1,-1};
1705                                 debug_printf( "job=%p being fed to run_command by busy_loop()'\n", &newjob);
1706                                 run_command(&newjob, inbg, pipefds);
1707                         }
1708                         else {
1709                                 free(command);
1710                                 command = (char *) xcalloc(BUFSIZ, sizeof(char));
1711                                 next_command = NULL;
1712                         }
1713                 } else {
1714                         /* a job is running in the foreground; wait for it */
1715                         i = 0;
1716                         while (!job_list.fg->progs[i].pid ||
1717                                    job_list.fg->progs[i].is_stopped == 1) i++;
1718
1719                         if (waitpid(job_list.fg->progs[i].pid, &status, WUNTRACED)<0)
1720                                 perror_msg_and_die("waitpid(%d)",job_list.fg->progs[i].pid);
1721
1722                         if (WIFEXITED(status) || WIFSIGNALED(status)) {
1723                                 /* the child exited */
1724                                 job_list.fg->running_progs--;
1725                                 job_list.fg->progs[i].pid = 0;
1726
1727 #ifdef BB_FEATURE_SH_ENVIRONMENT
1728                                 last_return_code=WEXITSTATUS(status);
1729                                 debug_printf("'%s' exited -- return code %d\n",
1730                                                 job_list.fg->text, last_return_code);
1731 #endif
1732                                 if (!job_list.fg->running_progs) {
1733                                         /* child exited */
1734                                         remove_job(&job_list, job_list.fg);
1735                                         job_list.fg = NULL;
1736                                 }
1737                         } else {
1738                                 /* the child was stopped */
1739                                 job_list.fg->stopped_progs++;
1740                                 job_list.fg->progs[i].is_stopped = 1;
1741
1742                                 if (job_list.fg->stopped_progs == job_list.fg->running_progs) {
1743                                         printf("\n" JOB_STATUS_FORMAT, job_list.fg->jobid,
1744                                                    "Stopped", job_list.fg->text);
1745                                         job_list.fg = NULL;
1746                                 }
1747                         }
1748
1749                         if (!job_list.fg) {
1750                                 /* move the shell to the foreground */
1751                                 /* suppress messages when run from /linuxrc mag@sysgo.de */
1752                                 if (tcsetpgrp(0, getpid()) && errno != ENOTTY)
1753                                         perror_msg("tcsetpgrp");
1754                         }
1755                 }
1756         }
1757         free(command);
1758
1759         /* return controlling TTY back to parent process group before exiting */
1760         if (tcsetpgrp(0, parent_pgrp))
1761                 perror_msg("tcsetpgrp");
1762
1763         /* return exit status if called with "-c" */
1764         if (input == NULL && WIFEXITED(status))
1765                 return WEXITSTATUS(status);
1766
1767         return 0;
1768 }
1769
1770
1771 #ifdef BB_FEATURE_CLEAN_UP
1772 void free_memory(void)
1773 {
1774         if (cwd)
1775                 free(cwd);
1776         if (local_pending_command)
1777                 free(local_pending_command);
1778
1779         if (job_list.fg && !job_list.fg->running_progs) {
1780                 remove_job(&job_list, job_list.fg);
1781         }
1782 }
1783 #endif
1784
1785
1786 int shell_main(int argc_l, char **argv_l)
1787 {
1788         int opt, interactive=FALSE;
1789         FILE *input = stdin;
1790         argc = argc_l;
1791         argv = argv_l;
1792
1793         /* These variables need re-initializing when recursing */
1794         shell_context = 0;
1795         cwd=NULL;
1796         local_pending_command = NULL;
1797         close_me_head = NULL;
1798         job_list.head = NULL;
1799         job_list.fg = NULL;
1800 #ifdef BB_FEATURE_SH_ENVIRONMENT
1801         last_bg_pid=1;
1802         last_return_code=1;
1803         show_x_trace=FALSE;
1804 #endif
1805
1806         if (argv[0] && argv[0][0] == '-') {
1807                 FILE *prof_input;
1808                 prof_input = fopen("/etc/profile", "r");
1809                 if (!prof_input) {
1810                         printf( "Couldn't open file '/etc/profile'\n");
1811                 } else {
1812                         int tmp_fd = fileno(prof_input);
1813                         mark_open(tmp_fd);
1814                         /* Now run the file */
1815                         busy_loop(prof_input);
1816                         fclose(prof_input);
1817                         mark_closed(tmp_fd);
1818                 }
1819         }
1820
1821         while ((opt = getopt(argc_l, argv_l, "cxi")) > 0) {
1822                 switch (opt) {
1823                         case 'c':
1824                                 input = NULL;
1825                                 if (local_pending_command != 0)
1826                                         error_msg_and_die("multiple -c arguments");
1827                                 local_pending_command = xstrdup(argv[optind]);
1828                                 optind++;
1829                                 argv = argv+optind;
1830                                 break;
1831 #ifdef BB_FEATURE_SH_ENVIRONMENT
1832                         case 'x':
1833                                 show_x_trace = TRUE;
1834                                 break;
1835 #endif
1836                         case 'i':
1837                                 interactive = TRUE;
1838                                 break;
1839                         default:
1840                                 show_usage();
1841                 }
1842         }
1843         /* A shell is interactive if the `-i' flag was given, or if all of
1844          * the following conditions are met:
1845          *        no -c command
1846          *    no arguments remaining or the -s flag given
1847          *    standard input is a terminal
1848          *    standard output is a terminal
1849          *    Refer to Posix.2, the description of the `sh' utility. */
1850         if (argv[optind]==NULL && input==stdin &&
1851                         isatty(fileno(stdin)) && isatty(fileno(stdout))) {
1852                 interactive=TRUE;
1853         }
1854         if (interactive==TRUE) {
1855                 //printf( "optind=%d  argv[optind]='%s'\n", optind, argv[optind]);
1856                 /* Looks like they want an interactive shell */
1857                 printf( "\n\nBusyBox v%s (%s) Built-in shell (lash)\n", BB_VER, BB_BT);
1858                 printf( "Enter 'help' for a list of built-in commands.\n\n");
1859         } else if (local_pending_command==NULL) {
1860                 //printf( "optind=%d  argv[optind]='%s'\n", optind, argv[optind]);
1861                 input = xfopen(argv[optind], "r");
1862                 mark_open(fileno(input));  /* be lazy, never mark this closed */
1863         }
1864
1865         /* initialize the cwd -- this is never freed...*/
1866         cwd=(char*)xmalloc(sizeof(char)*MAX_LINE+1);
1867         getcwd(cwd, sizeof(char)*MAX_LINE);
1868
1869 #ifdef BB_FEATURE_CLEAN_UP
1870         atexit(free_memory);
1871 #endif
1872
1873         return (busy_loop(input));
1874 }