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 -- sortof...
  43 #define BB_FEATURE_SH_IF_EXPRESSIONS
  44 //
  45 /* This is currently sortof broken, only for the brave... */
  46 #undef HANDLE_CONTINUATION_CHARS
  47 //
  48 /* This would be great -- if wordexp wouldn't strip all quoting
  49  * out from the target strings...  As is, a parser needs  */
  50 #undef BB_FEATURE_SH_WORDEXP
  51 //
  52 //For debugging/development on the shell only...
  53 //#define DEBUG_SHELL
  54
  55
  56 #include <stdio.h>
  57 #include <stdlib.h>
  58 #include <ctype.h>
  59 #include <errno.h>
  60 #include <fcntl.h>
  61 #include <signal.h>
  62 #include <string.h>
  63 #include <sys/ioctl.h>
  64 #include <sys/wait.h>
  65 #include <unistd.h>
  66 #include <getopt.h>
  67
  68 #undef BB_FEATURE_SH_WORDEXP
  69
  70 #if BB_FEATURE_SH_WORDEXP
  71 #include <wordexp.h>
  72 #define expand_t        wordexp_t
  73 #undef BB_FEATURE_SH_BACKTICKS
  74 #else
  75 #include <glob.h>
  76 #define expand_t        glob_t
  77 #endif
  78 #include "busybox.h"
  79 #include "cmdedit.h"
  80
  81
  82 static const int MAX_LINE = 256;        /* size of input buffer for cwd data */
  83 static const int MAX_READ = 128;        /* size of input buffer for `read' builtin */
  84 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
  85
  86
  87 enum redir_type { REDIRECT_INPUT, REDIRECT_OVERWRITE,
  88         REDIRECT_APPEND
  89 };
  90
  91 static const unsigned int DEFAULT_CONTEXT=0x1;
  92 static const unsigned int IF_TRUE_CONTEXT=0x2;
  93 static const unsigned int IF_FALSE_CONTEXT=0x4;
  94 static const unsigned int THEN_EXP_CONTEXT=0x8;
  95 static const unsigned int ELSE_EXP_CONTEXT=0x10;
  96
  97
  98 struct jobset {
  99         struct job *head;                       /* head of list of running jobs */
 100         struct job *fg;                         /* current foreground job */
 101 };
 102
 103 struct redir_struct {
 104         enum redir_type type;   /* type of redirection */
 105         int fd;                                         /* file descriptor being redirected */
 106         char *filename;                         /* file to redirect fd to */
 107 };
 108
 109 struct child_prog {
 110         pid_t pid;                                      /* 0 if exited */
 111         char **argv;                            /* program name and arguments */
 112         int num_redirects;                      /* elements in redirection array */
 113         struct redir_struct *redirects; /* I/O redirects */
 114         int is_stopped;                         /* is the program currently running? */
 115         struct job *family;                     /* pointer back to the child's parent job */
 116 };
 117
 118 struct job {
 119         int jobid;                                      /* job number */
 120         int num_progs;                          /* total number of programs in job */
 121         int running_progs;                      /* number of programs running */
 122         char *text;                                     /* name of job */
 123         char *cmdbuf;                           /* buffer various argv's point into */
 124         pid_t pgrp;                                     /* process group ID for the job */
 125         struct child_prog *progs;       /* array of programs in job */
 126         struct job *next;                       /* to track background commands */
 127         int stopped_progs;                      /* number of programs alive, but stopped */
 128         unsigned int job_context;       /* bitmask defining current context */
 129         struct jobset *job_list;
 130 };
 131
 132 struct built_in_command {
 133         char *cmd;                                      /* name */
 134         char *descr;                            /* description */
 135         int (*function) (struct child_prog *);  /* function ptr */
 136 };
 137
 138 struct close_me {
 139         int fd;
 140         struct close_me *next;
 141 };
 142
 143 /* function prototypes for builtins */
 144 static int builtin_cd(struct child_prog *cmd);
 145 static int builtin_env(struct child_prog *dummy);
 146 static int builtin_exec(struct child_prog *cmd);
 147 static int builtin_exit(struct child_prog *cmd);
 148 static int builtin_fg_bg(struct child_prog *cmd);
 149 static int builtin_help(struct child_prog *cmd);
 150 static int builtin_jobs(struct child_prog *dummy);
 151 static int builtin_pwd(struct child_prog *dummy);
 152 static int builtin_export(struct child_prog *cmd);
 153 static int builtin_source(struct child_prog *cmd);
 154 static int builtin_unset(struct child_prog *cmd);
 155 static int builtin_read(struct child_prog *cmd);
 156 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
 157 static int builtin_if(struct child_prog *cmd);
 158 static int builtin_then(struct child_prog *cmd);
 159 static int builtin_else(struct child_prog *cmd);
 160 static int builtin_fi(struct child_prog *cmd);
 161 /* function prototypes for shell stuff */
 162 static int run_command_predicate(char *cmd);
 163 #endif
 164
 165
 166 /* function prototypes for shell stuff */
 167 static void mark_open(int fd);
 168 static void mark_closed(int fd);
 169 static void close_all(void);
 170 static void checkjobs(struct jobset *job_list);
 171 static int get_command(FILE * source, char *command);
 172 static int parse_command(char **command_ptr, struct job *job, int *inbg);
 173 static int run_command(struct job *newjob, int inbg, int outpipe[2]);
 174 static int pseudo_exec(struct child_prog *cmd) __attribute__ ((noreturn));
 175 static int busy_loop(FILE * input);
 176
 177
 178 /* Table of built-in functions (these are non-forking builtins, meaning they
 179  * can change global variables in the parent shell process but they will not
 180  * work with pipes and redirects; 'unset foo | whatever' will not work) */
 181 static struct built_in_command bltins[] = {
 182         {"bg", "Resume a job in the background", builtin_fg_bg},
 183         {"cd", "Change working directory", builtin_cd},
 184         {"exec", "Exec command, replacing this shell with the exec'd process", builtin_exec},
 185         {"exit", "Exit from shell()", builtin_exit},
 186         {"fg", "Bring job into the foreground", builtin_fg_bg},
 187         {"jobs", "Lists the active jobs", builtin_jobs},
 188         {"export", "Set environment variable", builtin_export},
 189         {"unset", "Unset environment variable", builtin_unset},
 190         {"read", "Input environment variable", builtin_read},
 191         {".", "Source-in and run commands in a file", builtin_source},
 192         /* to do: add ulimit */
 193 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
 194         {"if", NULL, builtin_if},
 195         {"then", NULL, builtin_then},
 196         {"else", NULL, builtin_else},
 197         {"fi", NULL, builtin_fi},
 198 #endif
 199         {NULL, NULL, NULL}
 200 };
 201
 202 /* Table of forking built-in functions (things that fork cannot change global
 203  * variables in the parent process, such as the current working directory) */
 204 static struct built_in_command bltins_forking[] = {
 205         {"env", "Print all environment variables", builtin_env},
 206         {"pwd", "Print current directory", builtin_pwd},
 207         {"help", "List shell built-in commands", builtin_help},
 208         {NULL, NULL, NULL}
 209 };
 210
 211
 212 /* Variables we export */
 213 unsigned int shell_context;  /* Used in cmdedit.c to reset the
 214                                                                 context when someone hits ^C */
 215
 216
 217 /* Globals that are static to this file */
 218 static char *cwd;
 219 static char *local_pending_command = NULL;
 220 static struct jobset job_list = { NULL, NULL };
 221 static int argc;
 222 static char **argv;
 223 static struct close_me *close_me_head;
 224 #ifdef BB_FEATURE_SH_ENVIRONMENT
 225 static int last_bg_pid;
 226 static int last_return_code;
 227 static int show_x_trace;
 228 #endif
 229 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
 230 static char syntax_err[]="syntax error near unexpected token";
 231 #endif
 232
 233 static char *PS1;
 234 static char *PS2;
 235
 236
 237 #ifdef DEBUG_SHELL
 238 static inline void debug_printf(const char *format, ...)
 239 {
 240         va_list args;
 241         va_start(args, format);
 242         vfprintf(stderr, format, args);
 243         va_end(args);
 244 }
 245 #else
 246 static inline void debug_printf(const char *format, ...) { }
 247 #endif
 248
 249 /*
 250         Most builtins need access to the struct child_prog that has
 251         their arguments, previously coded as cmd->progs[0].  That coding
 252         can exhibit a bug, if the builtin is not the first command in
 253         a pipeline: "echo foo | exec sort" will attempt to exec foo.
 254
 255 builtin   previous use      notes
 256 ------ -----------------  ---------
 257 cd      cmd->progs[0]
 258 env     0
 259 exec    cmd->progs[0]  squashed bug: didn't look for applets or forking builtins
 260 exit    cmd->progs[0]
 261 fg_bg   cmd->progs[0], job_list->head, job_list->fg
 262 help    0
 263 jobs    job_list->head
 264 pwd     0
 265 export  cmd->progs[0]  passes cmd, job_list to builtin_env(), which ignores them
 266 source  cmd->progs[0]
 267 unset   cmd->progs[0]
 268 read    cmd->progs[0]
 269 if      cmd->job_context,  cmd->text
 270 then    cmd->job_context,  cmd->text
 271 else    cmd->job_context,  cmd->text
 272 fi      cmd->job_context
 273
 274 The use of cmd->text by if/then/else/fi is hopelessly hacky.
 275 Would it work to increment cmd->progs[0]->argv and recurse,
 276 somewhat like builtin_exec does?
 277
 278 I added "struct job *family;" to struct child_prog,
 279 and switched API to builtin_foo(struct child_prog *child);
 280 So   cmd->text        becomes  child->family->text
 281      cmd->job_context  becomes  child->family->job_context
 282      cmd->progs[0]    becomes  *child
 283      job_list          becomes  child->family->job_list
 284  */
 285
 286 /* built-in 'cd <path>' handler */
 287 static int builtin_cd(struct child_prog *child)
 288 {
 289         char *newdir;
 290
 291         if (child->argv[1] == NULL)
 292                 newdir = getenv("HOME");
 293         else
 294                 newdir = child->argv[1];
 295         if (chdir(newdir)) {
 296                 printf("cd: %s: %m\n", newdir);
 297                 return EXIT_FAILURE;
 298         }
 299         getcwd(cwd, sizeof(char)*MAX_LINE);
 300
 301         return EXIT_SUCCESS;
 302 }
 303
 304 /* built-in 'env' handler */
 305 static int builtin_env(struct child_prog *dummy)
 306 {
 307         char **e;
 308
 309         for (e = environ; *e; e++) {
 310                 printf( "%s\n", *e);
 311         }
 312         return (0);
 313 }
 314
 315 /* built-in 'exec' handler */
 316 static int builtin_exec(struct child_prog *child)
 317 {
 318         if (child->argv[1] == NULL)
 319                 return EXIT_SUCCESS;   /* Really? */
 320         child->argv++;
 321         close_all();
 322         pseudo_exec(child);
 323         /* never returns */
 324 }
 325
 326 /* built-in 'exit' handler */
 327 static int builtin_exit(struct child_prog *child)
 328 {
 329         if (child->argv[1] == NULL)
 330                 exit(EXIT_SUCCESS);
 331
 332         exit (atoi(child->argv[1]));
 333 }
 334
 335 /* built-in 'fg' and 'bg' handler */
 336 static int builtin_fg_bg(struct child_prog *child)
 337 {
 338         int i, jobNum;
 339         struct job *job=NULL;
 340
 341         if (!child->argv[1] || child->argv[2]) {
 342                 error_msg("%s: exactly one argument is expected",
 343                                 child->argv[0]);
 344                 return EXIT_FAILURE;
 345         }
 346
 347         if (sscanf(child->argv[1], "%%%d", &jobNum) != 1) {
 348                 error_msg("%s: bad argument '%s'",
 349                                 child->argv[0], child->argv[1]);
 350                 return EXIT_FAILURE;
 351         }
 352
 353         for (job = child->family->job_list->head; job; job = job->next) {
 354                 if (job->jobid == jobNum) {
 355                         break;
 356                 }
 357         }
 358
 359         if (!job) {
 360                 error_msg("%s: unknown job %d",
 361                                 child->argv[0], jobNum);
 362                 return EXIT_FAILURE;
 363         }
 364
 365         if (*child->argv[0] == 'f') {
 366                 /* Make this job the foreground job */
 367                 /* suppress messages when run from /linuxrc mag@sysgo.de */
 368                 if (tcsetpgrp(0, job->pgrp) && errno != ENOTTY)
 369                         perror_msg("tcsetpgrp");
 370                 child->family->job_list->fg = job;
 371         }
 372
 373         /* Restart the processes in the job */
 374         for (i = 0; i < job->num_progs; i++)
 375                 job->progs[i].is_stopped = 0;
 376
 377         kill(-job->pgrp, SIGCONT);
 378
 379         job->stopped_progs = 0;
 380
 381         return EXIT_SUCCESS;
 382 }
 383
 384 /* built-in 'help' handler */
 385 static int builtin_help(struct child_prog *dummy)
 386 {
 387         struct built_in_command *x;
 388
 389         printf("\nBuilt-in commands:\n");
 390         printf("-------------------\n");
 391         for (x = bltins; x->cmd; x++) {
 392                 if (x->descr==NULL)
 393                         continue;
 394                 printf("%s\t%s\n", x->cmd, x->descr);
 395         }
 396         for (x = bltins_forking; x->cmd; x++) {
 397                 if (x->descr==NULL)
 398                         continue;
 399                 printf("%s\t%s\n", x->cmd, x->descr);
 400         }
 401         printf("\n\n");
 402         return EXIT_SUCCESS;
 403 }
 404
 405 /* built-in 'jobs' handler */
 406 static int builtin_jobs(struct child_prog *child)
 407 {
 408         struct job *job;
 409         char *status_string;
 410
 411         for (job = child->family->job_list->head; job; job = job->next) {
 412                 if (job->running_progs == job->stopped_progs)
 413                         status_string = "Stopped";
 414                 else
 415                         status_string = "Running";
 416
 417                 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->text);
 418         }
 419         return EXIT_SUCCESS;
 420 }
 421
 422
 423 /* built-in 'pwd' handler */
 424 static int builtin_pwd(struct child_prog *dummy)
 425 {
 426         getcwd(cwd, MAX_LINE);
 427         printf( "%s\n", cwd);
 428         return EXIT_SUCCESS;
 429 }
 430
 431 /* built-in 'export VAR=value' handler */
 432 static int builtin_export(struct child_prog *child)
 433 {
 434         int res;
 435         char *v = child->argv[1];
 436
 437         if (v == NULL) {
 438                 return (builtin_env(child));
 439         }
 440         res = putenv(v);
 441         if (res)
 442                 fprintf(stderr, "export: %m\n");
 443 #ifndef BB_FEATURE_SH_SIMPLE_PROMPT
 444         if (strncmp(v, "PS1=", 4)==0)
 445                 PS1 = getenv("PS1");
 446         else if (strncmp(v, "PS2=", 4)==0)
 447                 PS2 = getenv("PS2");
 448 #endif
 449         return (res);
 450 }
 451
 452 /* built-in 'read VAR' handler */
 453 static int builtin_read(struct child_prog *child)
 454 {
 455         int res = 0, len, newlen;
 456         char *s;
 457         char string[MAX_READ];
 458
 459         if (child->argv[1]) {
 460                 /* argument (VAR) given: put "VAR=" into buffer */
 461                 strcpy(string, child->argv[1]);
 462                 len = strlen(string);
 463                 string[len++] = '=';
 464                 string[len]   = '\0';
 465                 fgets(&string[len], sizeof(string) - len, stdin);       /* read string */
 466                 newlen = strlen(string);
 467                 if(newlen > len)
 468                         string[--newlen] = '\0';        /* chomp trailing newline */
 469                 /*
 470                 ** string should now contain "VAR=<value>"
 471                 ** copy it (putenv() won't do that, so we must make sure
 472                 ** the string resides in a static buffer!)
 473                 */
 474                 res = -1;
 475                 if((s = strdup(string)))
 476                         res = putenv(s);
 477                 if (res)
 478                         fprintf(stderr, "read: %m\n");
 479         }
 480         else
 481                 fgets(string, sizeof(string), stdin);
 482
 483         return (res);
 484 }
 485
 486 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
 487 /* Built-in handler for 'if' commands */
 488 static int builtin_if(struct child_prog *child)
 489 {
 490         struct job *cmd = child->family;
 491         int status;
 492         char* charptr1=cmd->text+3; /* skip over the leading 'if ' */
 493
 494         /* Now run the 'if' command */
 495         debug_printf( "job=%p entering builtin_if ('%s')-- context=%d\n", cmd, charptr1, cmd->job_context);
 496         status = run_command_predicate(charptr1);
 497         debug_printf( "if test returned ");
 498         if (status == 0) {
 499                 debug_printf( "TRUE\n");
 500                 cmd->job_context |= IF_TRUE_CONTEXT;
 501         } else {
 502                 debug_printf( "FALSE\n");
 503                 cmd->job_context |= IF_FALSE_CONTEXT;
 504         }
 505         debug_printf("job=%p builtin_if set job context to %x\n", cmd, cmd->job_context);
 506         shell_context++;
 507
 508         return status;
 509 }
 510
 511 /* Built-in handler for 'then' (part of the 'if' command) */
 512 static int builtin_then(struct child_prog *child)
 513 {
 514         struct job *cmd = child->family;
 515         char* charptr1=cmd->text+5; /* skip over the leading 'then ' */
 516
 517         debug_printf( "job=%p entering builtin_then ('%s')-- context=%d\n", cmd, charptr1, cmd->job_context);
 518         if (! (cmd->job_context & (IF_TRUE_CONTEXT|IF_FALSE_CONTEXT))) {
 519                 shell_context = 0; /* Reset the shell's context on an error */
 520                 error_msg("%s `then'", syntax_err);
 521                 return EXIT_FAILURE;
 522         }
 523
 524         cmd->job_context |= THEN_EXP_CONTEXT;
 525         debug_printf("job=%p builtin_then set job context to %x\n", cmd, cmd->job_context);
 526
 527         /* If the if result was FALSE, skip the 'then' stuff */
 528         if (cmd->job_context & IF_FALSE_CONTEXT) {
 529                 return EXIT_SUCCESS;
 530         }
 531
 532         /* Seems the if result was TRUE, so run the 'then' command */
 533         debug_printf( "'then' now running '%s'\n", charptr1);
 534
 535         return(run_command_predicate(charptr1));
 536 }
 537
 538 /* Built-in handler for 'else' (part of the 'if' command) */
 539 static int builtin_else(struct child_prog *child)
 540 {
 541         struct job *cmd = child->family;
 542         char* charptr1=cmd->text+5; /* skip over the leading 'else ' */
 543
 544         debug_printf( "job=%p entering builtin_else ('%s')-- context=%d\n", cmd, charptr1, cmd->job_context);
 545
 546         if (! (cmd->job_context & THEN_EXP_CONTEXT)) {
 547                 shell_context = 0; /* Reset the shell's context on an error */
 548                 error_msg("%s `else'", syntax_err);
 549                 return EXIT_FAILURE;
 550         }
 551         /* If the if result was TRUE, skip the 'else' stuff */
 552         if (cmd->job_context & IF_TRUE_CONTEXT) {
 553                 return EXIT_SUCCESS;
 554         }
 555
 556         cmd->job_context |= ELSE_EXP_CONTEXT;
 557         debug_printf("job=%p builtin_else set job context to %x\n", cmd, cmd->job_context);
 558
 559         /* Now run the 'else' command */
 560         debug_printf( "'else' now running '%s'\n", charptr1);
 561         return(run_command_predicate(charptr1));
 562 }
 563
 564 /* Built-in handler for 'fi' (part of the 'if' command) */
 565 static int builtin_fi(struct child_prog *child)
 566 {
 567         struct job *cmd = child->family;
 568         debug_printf( "job=%p entering builtin_fi ('%s')-- context=%d\n", cmd, "", cmd->job_context);
 569         if (! (cmd->job_context & (IF_TRUE_CONTEXT|IF_FALSE_CONTEXT))) {
 570                 shell_context = 0; /* Reset the shell's context on an error */
 571                 error_msg("%s `fi'", syntax_err);
 572                 return EXIT_FAILURE;
 573         }
 574         /* Clear out the if and then context bits */
 575         cmd->job_context &= ~(IF_TRUE_CONTEXT|IF_FALSE_CONTEXT|THEN_EXP_CONTEXT|ELSE_EXP_CONTEXT);
 576         debug_printf("job=%p builtin_fi set job context to %x\n", cmd, cmd->job_context);
 577         shell_context--;
 578         return EXIT_SUCCESS;
 579 }
 580 #endif
 581
 582 /* Built-in '.' handler (read-in and execute commands from file) */
 583 static int builtin_source(struct child_prog *child)
 584 {
 585         FILE *input;
 586         int status;
 587         int fd;
 588
 589         if (child->argv[1] == NULL)
 590                 return EXIT_FAILURE;
 591
 592         input = fopen(child->argv[1], "r");
 593         if (!input) {
 594                 printf( "Couldn't open file '%s'\n", child->argv[1]);
 595                 return EXIT_FAILURE;
 596         }
 597
 598         fd=fileno(input);
 599         mark_open(fd);
 600         /* Now run the file */
 601         status = busy_loop(input);
 602         fclose(input);
 603         mark_closed(fd);
 604         return (status);
 605 }
 606
 607 /* built-in 'unset VAR' handler */
 608 static int builtin_unset(struct child_prog *child)
 609 {
 610         if (child->argv[1] == NULL) {
 611                 printf( "unset: parameter required.\n");
 612                 return EXIT_FAILURE;
 613         }
 614         unsetenv(child->argv[1]);
 615         return EXIT_SUCCESS;
 616 }
 617
 618 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
 619 /* currently used by if/then/else.
 620  *
 621  * Reparsing the command line for this purpose is gross,
 622  * incorrect, and fundamentally unfixable; in particular,
 623  * think about what happens with command substitution.
 624  * We really need to pull out the run, wait, return status
 625  * functionality out of busy_loop so we can child->argv++
 626  * and use that, without going back through parse_command.
 627  */
 628 static int run_command_predicate(char *cmd)
 629 {
 630         int n=strlen(cmd);
 631         local_pending_command = xmalloc(n+1);
 632         strncpy(local_pending_command, cmd, n);
 633         local_pending_command[n]='\0';
 634         return( busy_loop(NULL));
 635 }
 636 #endif
 637
 638 static void mark_open(int fd)
 639 {
 640         struct close_me *new = xmalloc(sizeof(struct close_me));
 641         new->fd = fd;
 642         new->next = close_me_head;
 643         close_me_head = new;
 644 }
 645
 646 static void mark_closed(int fd)
 647 {
 648         struct close_me *tmp;
 649         if (close_me_head == NULL || close_me_head->fd != fd)
 650                 error_msg_and_die("corrupt close_me");
 651         tmp = close_me_head;
 652         close_me_head = close_me_head->next;
 653         free(tmp);
 654 }
 655
 656 static void close_all()
 657 {
 658         struct close_me *c, *tmp;
 659         for (c=close_me_head; c; c=tmp) {
 660                 close(c->fd);
 661                 tmp=c->next;
 662                 free(c);
 663         }
 664         close_me_head = NULL;
 665 }
 666
 667
 668 /* free up all memory from a job */
 669 static void free_job(struct job *cmd)
 670 {
 671         int i;
 672         struct jobset *keep;
 673
 674         for (i = 0; i < cmd->num_progs; i++) {
 675                 free(cmd->progs[i].argv);
 676                 if (cmd->progs[i].redirects)
 677                         free(cmd->progs[i].redirects);
 678         }
 679         if (cmd->progs)
 680                 free(cmd->progs);
 681         if (cmd->text)
 682                 free(cmd->text);
 683         if (cmd->cmdbuf)
 684                 free(cmd->cmdbuf);
 685         keep = cmd->job_list;
 686         memset(cmd, 0, sizeof(struct job));
 687         cmd->job_list = keep;
 688 }
 689
 690 /* remove a job from the job_list */
 691 static void remove_job(struct jobset *job_list, struct job *job)
 692 {
 693         struct job *prevjob;
 694
 695         free_job(job);
 696         if (job == job_list->head) {
 697                 job_list->head = job->next;
 698         } else {
 699                 prevjob = job_list->head;
 700                 while (prevjob->next != job)
 701                         prevjob = prevjob->next;
 702                 prevjob->next = job->next;
 703         }
 704
 705         free(job);
 706 }
 707
 708 /* Checks to see if any background processes have exited -- if they
 709    have, figure out why and see if a job has completed */
 710 static void checkjobs(struct jobset *job_list)
 711 {
 712         struct job *job;
 713         pid_t childpid;
 714         int status;
 715         int prognum = 0;
 716
 717         while ((childpid = waitpid(-1, &status, WNOHANG | WUNTRACED)) > 0) {
 718                 for (job = job_list->head; job; job = job->next) {
 719                         prognum = 0;
 720                         while (prognum < job->num_progs &&
 721                                    job->progs[prognum].pid != childpid) prognum++;
 722                         if (prognum < job->num_progs)
 723                                 break;
 724                 }
 725
 726                 /* This happens on backticked commands */
 727                 if(job==NULL)
 728                         return;
 729
 730                 if (WIFEXITED(status) || WIFSIGNALED(status)) {
 731                         /* child exited */
 732                         job->running_progs--;
 733                         job->progs[prognum].pid = 0;
 734
 735                         if (!job->running_progs) {
 736                                 printf(JOB_STATUS_FORMAT, job->jobid, "Done", job->text);
 737                                 remove_job(job_list, job);
 738                         }
 739                 } else {
 740                         /* child stopped */
 741                         job->stopped_progs++;
 742                         job->progs[prognum].is_stopped = 1;
 743
 744                         if (job->stopped_progs == job->num_progs) {
 745                                 printf(JOB_STATUS_FORMAT, job->jobid, "Stopped",
 746                                            job->text);
 747                         }
 748                 }
 749         }
 750
 751         if (childpid == -1 && errno != ECHILD)
 752                 perror_msg("waitpid");
 753 }
 754
 755 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
 756  * and stderr if they are redirected. */
 757 static int setup_redirects(struct child_prog *prog, int squirrel[])
 758 {
 759         int i;
 760         int openfd;
 761         int mode = O_RDONLY;
 762         struct redir_struct *redir = prog->redirects;
 763
 764         for (i = 0; i < prog->num_redirects; i++, redir++) {
 765                 switch (redir->type) {
 766                 case REDIRECT_INPUT:
 767                         mode = O_RDONLY;
 768                         break;
 769                 case REDIRECT_OVERWRITE:
 770                         mode = O_WRONLY | O_CREAT | O_TRUNC;
 771                         break;
 772                 case REDIRECT_APPEND:
 773                         mode = O_WRONLY | O_CREAT | O_APPEND;
 774                         break;
 775                 }
 776
 777                 openfd = open(redir->filename, mode, 0666);
 778                 if (openfd < 0) {
 779                         /* this could get lost if stderr has been redirected, but
 780                            bash and ash both lose it as well (though zsh doesn't!) */
 781                         perror_msg("error opening %s", redir->filename);
 782                         return 1;
 783                 }
 784
 785                 if (openfd != redir->fd) {
 786                         if (squirrel && redir->fd < 3) {
 787                                 squirrel[redir->fd] = dup(redir->fd);
 788                         }
 789                         dup2(openfd, redir->fd);
 790                         close(openfd);
 791                 }
 792         }
 793
 794         return 0;
 795 }
 796
 797 static void restore_redirects(int squirrel[])
 798 {
 799         int i, fd;
 800         for (i=0; i<3; i++) {
 801                 fd = squirrel[i];
 802                 if (fd != -1) {
 803                         /* No error checking.  I sure wouldn't know what
 804                          * to do with an error if I found one! */
 805                         dup2(fd, i);
 806                         close(fd);
 807                 }
 808         }
 809 }
 810
 811 static inline void cmdedit_set_initial_prompt(void)
 812 {
 813 #ifdef BB_FEATURE_SH_SIMPLE_PROMPT
 814         PS1 = NULL;
 815         PS2 = "> ";
 816 #else
 817         PS1 = getenv("PS1");
 818         if(PS1==0) {
 819                 PS1 = "\\w \\$ ";
 820         }
 821         PS2 = getenv("PS2");
 822         if(PS2==0)
 823                 PS2 = "> ";
 824 #endif
 825 }
 826
 827 static inline void setup_prompt_string(char **prompt_str)
 828 {
 829 #ifdef BB_FEATURE_SH_SIMPLE_PROMPT
 830         /* Set up the prompt */
 831         if (shell_context == 0) {
 832                 if (PS1)
 833                         free(PS1);
 834                 PS1=xmalloc(strlen(cwd)+4);
 835                 sprintf(PS1, "%s %s", cwd, ( geteuid() != 0 ) ?  "$ ":"# ");
 836                 *prompt_str = PS1;
 837         } else {
 838                 *prompt_str = PS2;
 839         }
 840 #else
 841         *prompt_str = (shell_context==0)? PS1 : PS2;
 842 #endif
 843 }
 844
 845 static int get_command(FILE * source, char *command)
 846 {
 847         char *prompt_str;
 848
 849         if (source == NULL) {
 850                 if (local_pending_command) {
 851                         /* a command specified (-c option): return it & mark it done */
 852                         strcpy(command, local_pending_command);
 853                         free(local_pending_command);
 854                         local_pending_command = NULL;
 855                         return 0;
 856                 }
 857                 return 1;
 858         }
 859
 860         if (source == stdin) {
 861                 setup_prompt_string(&prompt_str);
 862
 863 #ifdef BB_FEATURE_COMMAND_EDITING
 864                 /*
 865                 ** enable command line editing only while a command line
 866                 ** is actually being read; otherwise, we'll end up bequeathing
 867                 ** atexit() handlers and other unwanted stuff to our
 868                 ** child processes (rob@sysgo.de)
 869                 */
 870                 cmdedit_read_input(prompt_str, command);
 871                 cmdedit_terminate();
 872                 return 0;
 873 #else
 874                 fputs(prompt_str, stdout);
 875 #endif
 876         }
 877
 878         if (!fgets(command, BUFSIZ - 2, source)) {
 879                 if (source == stdin)
 880                         printf("\n");
 881                 return 1;
 882         }
 883
 884         /* remove trailing newline */
 885         chomp(command);
 886
 887         return 0;
 888 }
 889
 890 #ifdef BB_FEATURE_SH_ENVIRONMENT
 891 static char* itoa(register int i)
 892 {
 893         static char a[7]; /* Max 7 ints */
 894         register char *b = a + sizeof(a) - 1;
 895         int   sign = (i < 0);
 896
 897         if (sign)
 898                 i = -i;
 899         *b = 0;
 900         do
 901         {
 902                 *--b = '0' + (i % 10);
 903                 i /= 10;
 904         }
 905         while (i);
 906         if (sign)
 907                 *--b = '-';
 908         return b;
 909 }
 910 #endif
 911
 912 #if defined BB_FEATURE_SH_ENVIRONMENT && ! defined BB_FEATURE_SH_WORDEXP
 913 char * strsep_space( char *string, int * index)
 914 {
 915         char *token, *begin;
 916
 917         begin = string;
 918
 919         /* Short circuit the trivial case */
 920         if ( !string || ! string[*index])
 921                 return NULL;
 922
 923         /* Find the end of the token. */
 924         while( string && string[*index] && !isspace(string[*index]) ) {
 925                 (*index)++;
 926         }
 927
 928         /* Find the end of any whitespace trailing behind
 929          * the token and let that be part of the token */
 930         while( string && string[*index] && isspace(string[*index]) ) {
 931                 (*index)++;
 932         }
 933
 934         if (! string && *index==0) {
 935                 /* Nothing useful was found */
 936                 return NULL;
 937         }
 938
 939         token = xmalloc(*index);
 940         token[*index] = '\0';
 941         strncpy(token, string,  *index);
 942
 943         return token;
 944 }
 945 #endif
 946
 947
 948 static int expand_arguments(char *command)
 949 {
 950 #ifdef BB_FEATURE_SH_ENVIRONMENT
 951         expand_t expand_result;
 952         char *src, *dst, *var;
 953         int index = 0;
 954         int i=0, length, total_length=0, retval;
 955         const char *out_of_space = "out of space during expansion";
 956 #endif
 957
 958         /* get rid of the terminating \n */
 959         chomp(command);
 960
 961         /* Fix up escape sequences to be the Real Thing(tm) */
 962         while( command && command[index]) {
 963                 if (command[index] == '\\') {
 964                         char *tmp = command+index+1;
 965                         command[index+1] = process_escape_sequence(  &tmp );
 966                         memmove(command+index, command+index+1, strlen(command+index));
 967                 }
 968                 index++;
 969         }
 970
 971 #ifdef BB_FEATURE_SH_ENVIRONMENT
 972
 973
 974 #if BB_FEATURE_SH_WORDEXP
 975         /* This first part uses wordexp() which is a wonderful C lib
 976          * function which expands nearly everything.  */
 977         retval = wordexp (command, &expand_result, WRDE_SHOWERR);
 978         if (retval == WRDE_NOSPACE) {
 979                 /* Mem may have been allocated... */
 980                 wordfree (&expand_result);
 981                 error_msg(out_of_space);
 982                 return FALSE;
 983         }
 984         if (retval < 0) {
 985                 /* Some other error.  */
 986                 error_msg("syntax error");
 987                 return FALSE;
 988         }
 989
 990         if (expand_result.we_wordc > 0) {
 991                 /* Convert from char** (one word per string) to a simple char*,
 992                  * but don't overflow command which is BUFSIZ in length */
 993                 *command = '\0';
 994                 while (i < expand_result.we_wordc && total_length < BUFSIZ) {
 995                         length=strlen(expand_result.we_wordv[i])+1;
 996                         if (BUFSIZ-total_length-length <= 0) {
 997                                 error_msg(out_of_space);
 998                                 return FALSE;
 999                         }
1000                         strcat(command+total_length, expand_result.we_wordv[i++]);
1001                         strcat(command+total_length, " ");
1002                         total_length+=length;
1003                 }
1004                 wordfree (&expand_result);
1005         }
1006 #else
1007
1008         /* Ok.  They don't have a recent glibc and they don't have uClibc.  Chances
1009          * are about 100% they don't have wordexp(). So instead the best we can do
1010          * is use glob and then fixup environment variables and such ourselves.
1011          * This is better then nothing, but certainly not perfect */
1012
1013         /* It turns out that glob is very stupid.  We have to feed it one word at a
1014          * time since it can't cope with a full string.  Here we convert command
1015          * (char*) into cmd (char**, one word per string) */
1016         {
1017
1018                 int flags = GLOB_NOCHECK
1019 #ifdef GLOB_BRACE
1020                                 | GLOB_BRACE
1021 #endif
1022 #ifdef GLOB_TILDE
1023                                 | GLOB_TILDE
1024 #endif
1025                         ;
1026                 char *tmpcmd, *cmd, *cmd_copy;
1027                 /* We need a clean copy, so strsep can mess up the copy while
1028                  * we write stuff into the original (in a minute) */
1029                 cmd = cmd_copy = strdup(command);
1030                 *command = '\0';
1031                 for (index = 0, tmpcmd = cmd;
1032                                 (tmpcmd = strsep_space(cmd, &index)) != NULL; cmd += index, index=0) {
1033                         if (*tmpcmd == '\0')
1034                                 break;
1035                         retval = glob(tmpcmd, flags, NULL, &expand_result);
1036                         free(tmpcmd); /* Free mem allocated by strsep_space */
1037                         if (retval == GLOB_NOSPACE) {
1038                                 /* Mem may have been allocated... */
1039                                 globfree (&expand_result);
1040                                 error_msg(out_of_space);
1041                                 return FALSE;
1042                         } else if (retval != 0) {
1043                                 /* Some other error.  GLOB_NOMATCH shouldn't
1044                                  * happen because of the GLOB_NOCHECK flag in
1045                                  * the glob call. */
1046                                 error_msg("syntax error");
1047                                 return FALSE;
1048                         } else {
1049                         /* Convert from char** (one word per string) to a simple char*,
1050                          * but don't overflow command which is BUFSIZ in length */
1051                                 for (i=0; i < expand_result.gl_pathc; i++) {
1052                                         length=strlen(expand_result.gl_pathv[i])+1;
1053                                         if (BUFSIZ-total_length-length <= 0) {
1054                                                 error_msg(out_of_space);
1055                                                 return FALSE;
1056                                         }
1057                                         strcat(command+total_length, expand_result.gl_pathv[i]);
1058                                         strcat(command+total_length, " ");
1059                                         total_length+=length;
1060                                 }
1061                                 globfree (&expand_result);
1062                         }
1063                 }
1064                 free(cmd_copy);
1065                 trim(command);
1066         }
1067
1068 #endif
1069
1070         /* Now do the shell variable substitutions which
1071          * wordexp can't do for us, namely $? and $! */
1072         src = command;
1073         while((dst = strchr(src,'$')) != NULL){
1074                 var = NULL;
1075                 switch(*(dst+1)) {
1076                         case '?':
1077                                 var = itoa(last_return_code);
1078                                 break;
1079                         case '!':
1080                                 if (last_bg_pid==-1)
1081                                         *(var)='\0';
1082                                 else
1083                                         var = itoa(last_bg_pid);
1084                                 break;
1085                                 /* Everything else like $$, $#, $[0-9], etc should all be
1086                                  * expanded by wordexp(), so we can in theory skip that stuff
1087                                  * here, but just to be on the safe side (i.e. since uClibc
1088                                  * wordexp doesn't do this stuff yet), lets leave it in for
1089                                  * now. */
1090                         case '$':
1091                                 var = itoa(getpid());
1092                                 break;
1093                         case '#':
1094                                 var = itoa(argc-1);
1095                                 break;
1096                         case '0':case '1':case '2':case '3':case '4':
1097                         case '5':case '6':case '7':case '8':case '9':
1098                                 {
1099                                         int index=*(dst + 1)-48;
1100                                         if (index >= argc) {
1101                                                 var='\0';
1102                                         } else {
1103                                                 var = argv[index];
1104                                         }
1105                                 }
1106                                 break;
1107
1108                 }
1109                 if (var) {
1110                         /* a single character construction was found, and
1111                          * already handled in the case statement */
1112                         src=dst+2;
1113                 } else {
1114                         /* Looks like an environment variable */
1115                         char delim_hold;
1116                         int num_skip_chars=1;
1117                         int dstlen = strlen(dst);
1118                         /* Is this a ${foo} type variable? */
1119                         if (dstlen >=2 && *(dst+1) == '{') {
1120                                 src=strchr(dst+1, '}');
1121                                 num_skip_chars=2;
1122                         } else {
1123                                 src=strpbrk(dst+1, " \t~`!$^&*()=|\\[];\"'<>?./");
1124                         }
1125                         if (src == NULL) {
1126                                 src = dst+dstlen;
1127                         }
1128                         delim_hold=*src;
1129                         *src='\0';  /* temporary */
1130                         var = getenv(dst + num_skip_chars);
1131                         *src=delim_hold;
1132                         if (num_skip_chars==2) {
1133                                 src++;
1134                         }
1135                 }
1136                 if (var == NULL) {
1137                         /* Seems we got an un-expandable variable.  So delete it. */
1138                         var = "";
1139                 }
1140                 {
1141                         int subst_len = strlen(var);
1142                         int trail_len = strlen(src);
1143                         if (dst+subst_len+trail_len >= command+BUFSIZ) {
1144                                 error_msg(out_of_space);
1145                                 return FALSE;
1146                         }
1147                         /* Move stuff to the end of the string to accommodate
1148                          * filling the created gap with the new stuff */
1149                         memmove(dst+subst_len, src, trail_len);
1150                         *(dst+subst_len+trail_len)='\0';
1151                         /* Now copy in the new stuff */
1152                         memcpy(dst, var, subst_len);
1153                         src = dst+subst_len;
1154                 }
1155         }
1156
1157 #endif
1158         return TRUE;
1159 }
1160
1161 /* Return cmd->num_progs as 0 if no command is present (e.g. an empty
1162    line). If a valid command is found, command_ptr is set to point to
1163    the beginning of the next command (if the original command had more
1164    then one job associated with it) or NULL if no more commands are
1165    present. */
1166 static int parse_command(char **command_ptr, struct job *job, int *inbg)
1167 {
1168         char *command;
1169         char *return_command = NULL;
1170         char *src, *buf, *chptr;
1171         int argc_l = 0;
1172         int done = 0;
1173         int argv_alloced;
1174         int i;
1175         char quote = '\0';
1176         int count;
1177         struct child_prog *prog;
1178
1179         /* skip leading white space */
1180         while (**command_ptr && isspace(**command_ptr))
1181                 (*command_ptr)++;
1182
1183         /* this handles empty lines or leading '#' characters */
1184         if (!**command_ptr || (**command_ptr == '#')) {
1185                 job->num_progs=0;
1186                 return 0;
1187         }
1188
1189         *inbg = 0;
1190         job->num_progs = 1;
1191         job->progs = xmalloc(sizeof(*job->progs));
1192
1193         /* We set the argv elements to point inside of this string. The
1194            memory is freed by free_job(). Allocate twice the original
1195            length in case we need to quote every single character.
1196
1197            Getting clean memory relieves us of the task of NULL
1198            terminating things and makes the rest of this look a bit
1199            cleaner (though it is, admittedly, a tad less efficient) */
1200         job->cmdbuf = command = xcalloc(2*strlen(*command_ptr) + 1, sizeof(char));
1201         job->text = NULL;
1202
1203         prog = job->progs;
1204         prog->num_redirects = 0;
1205         prog->redirects = NULL;
1206         prog->is_stopped = 0;
1207         prog->family = job;
1208
1209         argv_alloced = 5;
1210         prog->argv = xmalloc(sizeof(*prog->argv) * argv_alloced);
1211         prog->argv[0] = job->cmdbuf;
1212
1213         buf = command;
1214         src = *command_ptr;
1215         while (*src && !done) {
1216                 if (quote == *src) {
1217                         quote = '\0';
1218                 } else if (quote) {
1219                         if (*src == '\\') {
1220                                 src++;
1221                                 if (!*src) {
1222                                         error_msg("character expected after \\");
1223                                         free_job(job);
1224                                         return 1;
1225                                 }
1226
1227                                 /* in shell, "\'" should yield \' */
1228                                 if (*src != quote) {
1229                                         *buf++ = '\\';
1230                                         *buf++ = '\\';
1231                                 }
1232                         } else if (*src == '*' || *src == '?' || *src == '[' ||
1233                                            *src == ']') *buf++ = '\\';
1234                         *buf++ = *src;
1235                 } else if (isspace(*src)) {
1236                         if (*prog->argv[argc_l]) {
1237                                 buf++, argc_l++;
1238                                 /* +1 here leaves room for the NULL which ends argv */
1239                                 if ((argc_l + 1) == argv_alloced) {
1240                                         argv_alloced += 5;
1241                                         prog->argv = xrealloc(prog->argv,
1242                                                                                   sizeof(*prog->argv) *
1243                                                                                   argv_alloced);
1244                                 }
1245                                 prog->argv[argc_l] = buf;
1246                         }
1247                 } else
1248                         switch (*src) {
1249                         case '"':
1250                         case '\'':
1251                                 quote = *src;
1252                                 break;
1253
1254                         case '#':                       /* comment */
1255                                 if (*(src-1)== '$')
1256                                         *buf++ = *src;
1257                                 else
1258                                         done = 1;
1259                                 break;
1260
1261                         case '>':                       /* redirects */
1262                         case '<':
1263                                 i = prog->num_redirects++;
1264                                 prog->redirects = xrealloc(prog->redirects,
1265                                                                                           sizeof(*prog->redirects) *
1266                                                                                           (i + 1));
1267
1268                                 prog->redirects[i].fd = -1;
1269                                 if (buf != prog->argv[argc_l]) {
1270                                         /* the stuff before this character may be the file number
1271                                            being redirected */
1272                                         prog->redirects[i].fd =
1273                                                 strtol(prog->argv[argc_l], &chptr, 10);
1274
1275                                         if (*chptr && *prog->argv[argc_l]) {
1276                                                 buf++, argc_l++;
1277                                                 prog->argv[argc_l] = buf;
1278                                         }
1279                                 }
1280
1281                                 if (prog->redirects[i].fd == -1) {
1282                                         if (*src == '>')
1283                                                 prog->redirects[i].fd = 1;
1284                                         else
1285                                                 prog->redirects[i].fd = 0;
1286                                 }
1287
1288                                 if (*src++ == '>') {
1289                                         if (*src == '>')
1290                                                 prog->redirects[i].type =
1291                                                         REDIRECT_APPEND, src++;
1292                                         else
1293                                                 prog->redirects[i].type = REDIRECT_OVERWRITE;
1294                                 } else {
1295                                         prog->redirects[i].type = REDIRECT_INPUT;
1296                                 }
1297
1298                                 /* This isn't POSIX sh compliant. Oh well. */
1299                                 chptr = src;
1300                                 while (isspace(*chptr))
1301                                         chptr++;
1302
1303                                 if (!*chptr) {
1304                                         error_msg("file name expected after %c", *(src-1));
1305                                         free_job(job);
1306                                         job->num_progs=0;
1307                                         return 1;
1308                                 }
1309
1310                                 prog->redirects[i].filename = buf;
1311                                 while (*chptr && !isspace(*chptr))
1312                                         *buf++ = *chptr++;
1313
1314                                 src = chptr - 1;        /* we src++ later */
1315                                 prog->argv[argc_l] = ++buf;
1316                                 break;
1317
1318                         case '|':                       /* pipe */
1319                                 /* finish this command */
1320                                 if (*prog->argv[argc_l])
1321                                         argc_l++;
1322                                 if (!argc_l) {
1323                                         error_msg("empty command in pipe");
1324                                         free_job(job);
1325                                         job->num_progs=0;
1326                                         return 1;
1327                                 }
1328                                 prog->argv[argc_l] = NULL;
1329
1330                                 /* and start the next */
1331                                 job->num_progs++;
1332                                 job->progs = xrealloc(job->progs,
1333                                                                           sizeof(*job->progs) * job->num_progs);
1334                                 prog = job->progs + (job->num_progs - 1);
1335                                 prog->num_redirects = 0;
1336                                 prog->redirects = NULL;
1337                                 prog->is_stopped = 0;
1338                                 prog->family = job;
1339                                 argc_l = 0;
1340
1341                                 argv_alloced = 5;
1342                                 prog->argv = xmalloc(sizeof(*prog->argv) * argv_alloced);
1343                                 prog->argv[0] = ++buf;
1344
1345                                 src++;
1346                                 while (*src && isspace(*src))
1347                                         src++;
1348
1349                                 if (!*src) {
1350                                         error_msg("empty command in pipe");
1351                                         free_job(job);
1352                                         job->num_progs=0;
1353                                         return 1;
1354                                 }
1355                                 src--;                  /* we'll ++ it at the end of the loop */
1356
1357                                 break;
1358
1359                         case '&':                       /* background */
1360                                 *inbg = 1;
1361                         case ';':                       /* multiple commands */
1362                                 done = 1;
1363                                 return_command = *command_ptr + (src - *command_ptr) + 1;
1364                                 break;
1365
1366 #ifdef BB_FEATURE_SH_BACKTICKS
1367                         case '`':
1368                                 /* Exec a backtick-ed command */
1369                                 /* Besides any previous brokenness, I have not
1370                                  * updated backtick handling for close_me support.
1371                                  * I don't know if it needs it or not.  -- LRD */
1372                                 {
1373                                         char* charptr1=NULL, *charptr2;
1374                                         char* ptr=NULL;
1375                                         struct job *newjob;
1376                                         struct jobset njob_list = { NULL, NULL };
1377                                         int pipefd[2];
1378                                         int size;
1379
1380                                         ptr=strchr(++src, '`');
1381                                         if (ptr==NULL) {
1382                                                 fprintf(stderr, "Unmatched '`' in command\n");
1383                                                 free_job(job);
1384                                                 return 1;
1385                                         }
1386
1387                                         /* Make some space to hold just the backticked command */
1388                                         charptr1 = charptr2 = xmalloc(1+ptr-src);
1389                                         memcpy(charptr1, src, ptr-src);
1390                                         charptr1[ptr-src] = '\0';
1391                                         newjob = xmalloc(sizeof(struct job));
1392                                         newjob->job_list = &njob_list;
1393                                         /* Now parse and run the backticked command */
1394                                         if (!parse_command(&charptr1, newjob, inbg)
1395                                                         && newjob->num_progs) {
1396                                                 pipe(pipefd);
1397                                                 run_command(newjob, 0, pipefd);
1398                                         }
1399                                         checkjobs(job->job_list);
1400                                         free_job(newjob);  /* doesn't actually free newjob,
1401                                                              looks like a memory leak */
1402                                         free(charptr2);
1403
1404                                         /* Make a copy of any stuff left over in the command
1405                                          * line after the second backtick */
1406                                         charptr2 = xmalloc(strlen(ptr)+1);
1407                                         memcpy(charptr2, ptr+1, strlen(ptr));
1408
1409
1410                                         /* Copy the output from the backtick-ed command into the
1411                                          * command line, making extra room as needed  */
1412                                         --src;
1413                                         charptr1 = xmalloc(BUFSIZ);
1414                                         while ( (size=full_read(pipefd[0], charptr1, BUFSIZ-1)) >0) {
1415                                                 int newsize=src - *command_ptr + size + 1 + strlen(charptr2);
1416                                                 if (newsize > BUFSIZ) {
1417                                                         *command_ptr=xrealloc(*command_ptr, newsize);
1418                                                 }
1419                                                 memcpy(src, charptr1, size);
1420                                                 src+=size;
1421                                         }
1422                                         free(charptr1);
1423                                         close(pipefd[0]);
1424                                         if (*(src-1)=='\n')
1425                                                 --src;
1426
1427                                         /* Now paste into the *command_ptr all the stuff
1428                                          * leftover after the second backtick */
1429                                         memcpy(src, charptr2, strlen(charptr2)+1);
1430                                         free(charptr2);
1431
1432                                         /* Now recursively call parse_command to deal with the new
1433                                          * and improved version of the command line with the backtick
1434                                          * results expanded in place... */
1435                                         {
1436                                                 struct jobset *jl=job->job_list;
1437                                                 free_job(job);
1438                                                 job->job_list = jl;
1439                                         }
1440                                         return(parse_command(command_ptr, job, inbg));
1441                                 }
1442                                 break;
1443 #endif // BB_FEATURE_SH_BACKTICKS
1444
1445                         case '\\':
1446                                 src++;
1447                                 if (!*src) {
1448 /* This is currently a little broken... */
1449 #ifdef HANDLE_CONTINUATION_CHARS
1450                                         /* They fed us a continuation char, so continue reading stuff
1451                                          * on the next line, then tack that onto the end of the current
1452                                          * command */
1453                                         char *command;
1454                                         int newsize;
1455                                         printf("erik: found a continue char at EOL...\n");
1456                                         command = (char *) xcalloc(BUFSIZ, sizeof(char));
1457                                         if (get_command(input, command)) {
1458                                                 error_msg("character expected after \\");
1459                                                 free(command);
1460                                                 free_job(job);
1461                                                 return 1;
1462                                         }
1463                                         newsize = strlen(*command_ptr) + strlen(command) + 2;
1464                                         if (newsize > BUFSIZ) {
1465                                                 printf("erik: doing realloc\n");
1466                                                 *command_ptr=xrealloc(*command_ptr, newsize);
1467                                         }
1468                                         printf("erik: A: *command_ptr='%s'\n", *command_ptr);
1469                                         memcpy(--src, command, strlen(command));
1470                                         printf("erik: B: *command_ptr='%s'\n", *command_ptr);
1471                                         free(command);
1472                                         break;
1473 #else
1474                                         error_msg("character expected after \\");
1475                                         free(command);
1476                                         free_job(job);
1477                                         return 1;
1478 #endif
1479                                 }
1480                                 if (*src == '*' || *src == '[' || *src == ']'
1481                                         || *src == '?') *buf++ = '\\';
1482                                 /* fallthrough */
1483                         default:
1484                                 *buf++ = *src;
1485                         }
1486
1487                 src++;
1488         }
1489
1490         if (*prog->argv[argc_l]) {
1491                 argc_l++;
1492         }
1493         if (!argc_l) {
1494                 free_job(job);
1495                 return 0;
1496         }
1497         prog->argv[argc_l] = NULL;
1498
1499         if (!return_command) {
1500                 job->text = xmalloc(strlen(*command_ptr) + 1);
1501                 strcpy(job->text, *command_ptr);
1502         } else {
1503                 /* This leaves any trailing spaces, which is a bit sloppy */
1504                 count = return_command - *command_ptr;
1505                 job->text = xmalloc(count + 1);
1506                 strncpy(job->text, *command_ptr, count);
1507                 job->text[count] = '\0';
1508         }
1509
1510         *command_ptr = return_command;
1511
1512         return 0;
1513 }
1514
1515 /* Run the child_prog, no matter what kind of command it uses.
1516  */
1517 static int pseudo_exec(struct child_prog *child)
1518 {
1519         struct built_in_command *x;
1520 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
1521         char *name;
1522 #endif
1523
1524         /* Check if the command matches any of the non-forking builtins.
1525          * Depending on context, this might be redundant.  But it's
1526          * easier to waste a few CPU cycles than it is to figure out
1527          * if this is one of those cases.
1528          */
1529         for (x = bltins; x->cmd; x++) {
1530                 if (strcmp(child->argv[0], x->cmd) == 0 ) {
1531                         exit(x->function(child));
1532                 }
1533         }
1534
1535         /* Check if the command matches any of the forking builtins. */
1536         for (x = bltins_forking; x->cmd; x++) {
1537                 if (strcmp(child->argv[0], x->cmd) == 0) {
1538                         applet_name=x->cmd;
1539                         exit (x->function(child));
1540                 }
1541         }
1542 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
1543         /* Check if the command matches any busybox internal
1544          * commands ("applets") here.  Following discussions from
1545          * November 2000 on busybox@opensource.lineo.com, don't use
1546          * get_last_path_component().  This way explicit (with
1547          * slashes) filenames will never be interpreted as an
1548          * applet, just like with builtins.  This way the user can
1549          * override an applet with an explicit filename reference.
1550          * The only downside to this change is that an explicit
1551          * /bin/foo invocation will fork and exec /bin/foo, even if
1552          * /bin/foo is a symlink to busybox.
1553          */
1554         name = child->argv[0];
1555
1556 #ifdef BB_FEATURE_SH_APPLETS_ALWAYS_WIN
1557         /* If you enable BB_FEATURE_SH_APPLETS_ALWAYS_WIN, then
1558          * if you run /bin/cat, it will use BusyBox cat even if
1559          * /bin/cat exists on the filesystem and is _not_ busybox.
1560          * Some systems want this, others do not.  Choose wisely.  :-)
1561          */
1562         name = get_last_path_component(name);
1563 #endif
1564
1565         {
1566             char** argv=child->argv;
1567             int argc_l;
1568             for(argc_l=0;*argv!=NULL; argv++, argc_l++);
1569             optind = 1;
1570             run_applet_by_name(name, argc_l, child->argv);
1571         }
1572 #endif
1573
1574         execvp(child->argv[0], child->argv);
1575         perror_msg_and_die("%s", child->argv[0]);
1576 }
1577
1578 static void insert_job(struct job *newjob, int inbg)
1579 {
1580         struct job *thejob;
1581         struct jobset *job_list=newjob->job_list;
1582
1583         /* find the ID for thejob to use */
1584         newjob->jobid = 1;
1585         for (thejob = job_list->head; thejob; thejob = thejob->next)
1586                 if (thejob->jobid >= newjob->jobid)
1587                         newjob->jobid = thejob->jobid + 1;
1588
1589         /* add thejob to the list of running jobs */
1590         if (!job_list->head) {
1591                 thejob = job_list->head = xmalloc(sizeof(*thejob));
1592         } else {
1593                 for (thejob = job_list->head; thejob->next; thejob = thejob->next) /* nothing */;
1594                 thejob->next = xmalloc(sizeof(*thejob));
1595                 thejob = thejob->next;
1596         }
1597
1598         *thejob = *newjob;   /* physically copy the struct job */
1599         thejob->next = NULL;
1600         thejob->running_progs = thejob->num_progs;
1601         thejob->stopped_progs = 0;
1602
1603         if (inbg) {
1604                 /* we don't wait for background thejobs to return -- append it
1605                    to the list of backgrounded thejobs and leave it alone */
1606                 printf("[%d] %d\n", thejob->jobid,
1607                            newjob->progs[newjob->num_progs - 1].pid);
1608 #ifdef BB_FEATURE_SH_ENVIRONMENT
1609                 last_bg_pid=newjob->progs[newjob->num_progs - 1].pid;
1610 #endif
1611         } else {
1612                 newjob->job_list->fg = thejob;
1613
1614                 /* move the new process group into the foreground */
1615                 /* suppress messages when run from /linuxrc mag@sysgo.de */
1616                 if (tcsetpgrp(0, newjob->pgrp) && errno != ENOTTY)
1617                         perror_msg("tcsetpgrp");
1618         }
1619 }
1620
1621 static int run_command(struct job *newjob, int inbg, int outpipe[2])
1622 {
1623         /* struct job *thejob; */
1624         int i;
1625         int nextin, nextout;
1626         int pipefds[2];                         /* pipefd[0] is for reading */
1627         struct built_in_command *x;
1628         struct child_prog *child;
1629
1630         nextin = 0, nextout = 1;
1631         for (i = 0; i < newjob->num_progs; i++) {
1632                 child = & (newjob->progs[i]);
1633
1634                 if ((i + 1) < newjob->num_progs) {
1635                         if (pipe(pipefds)<0) perror_msg_and_die("pipe");
1636                         nextout = pipefds[1];
1637                 } else {
1638                         if (outpipe[1]!=-1) {
1639                                 nextout = outpipe[1];
1640                         } else {
1641                                 nextout = 1;
1642                         }
1643                 }
1644
1645 #ifdef BB_FEATURE_SH_ENVIRONMENT
1646                 if (show_x_trace==TRUE) {
1647                         int j;
1648                         fputc('+', stderr);
1649                         for (j = 0; child->argv[j]; j++) {
1650                                 fputc(' ', stderr);
1651                                 fputs(child->argv[j], stderr);
1652                         }
1653                         fputc('\n', stderr);
1654                 }
1655 #endif
1656
1657                 /* Check if the command matches any non-forking builtins,
1658                  * but only if this is a simple command.
1659                  * Non-forking builtins within pipes have to fork anyway,
1660                  * and are handled in pseudo_exec.  "echo foo | read bar"
1661                  * is doomed to failure, and doesn't work on bash, either.
1662                  */
1663                 if (newjob->num_progs == 1) {
1664                         for (x = bltins; x->cmd; x++) {
1665                                 if (strcmp(child->argv[0], x->cmd) == 0 ) {
1666                                         int squirrel[] = {-1, -1, -1};
1667                                         int rcode;
1668                                         setup_redirects(child, squirrel);
1669                                         rcode = x->function(child);
1670                                         restore_redirects(squirrel);
1671                                         return rcode;
1672                                 }
1673                         }
1674                 }
1675
1676                 if (!(child->pid = fork())) {
1677                         signal(SIGTTOU, SIG_DFL);
1678
1679                         close_all();
1680
1681                         if (outpipe[1]!=-1) {
1682                                 close(outpipe[0]);
1683                         }
1684                         if (nextin != 0) {
1685                                 dup2(nextin, 0);
1686                                 close(nextin);
1687                         }
1688
1689                         if (nextout != 1) {
1690                                 dup2(nextout, 1);
1691                                 dup2(nextout, 2);  /* Really? */
1692                                 close(nextout);
1693                                 close(pipefds[0]);
1694                         }
1695
1696                         /* explicit redirects override pipes */
1697                         setup_redirects(child,NULL);
1698
1699                         pseudo_exec(child);
1700                 }
1701                 if (outpipe[1]!=-1) {
1702                         close(outpipe[1]);
1703                 }
1704
1705                 /* put our child in the process group whose leader is the
1706                    first process in this pipe */
1707                 setpgid(child->pid, newjob->progs[0].pid);
1708                 if (nextin != 0)
1709                         close(nextin);
1710                 if (nextout != 1)
1711                         close(nextout);
1712
1713                 /* If there isn't another process, nextin is garbage
1714                    but it doesn't matter */
1715                 nextin = pipefds[0];
1716         }
1717
1718         newjob->pgrp = newjob->progs[0].pid;
1719
1720         insert_job(newjob, inbg);
1721
1722         return 0;
1723 }
1724
1725 static int busy_loop(FILE * input)
1726 {
1727         char *command;
1728         char *next_command = NULL;
1729         struct job newjob;
1730         pid_t  parent_pgrp;
1731         int i;
1732         int inbg;
1733         int status;
1734         newjob.job_list = &job_list;
1735         newjob.job_context = DEFAULT_CONTEXT;
1736
1737         /* save current owner of TTY so we can restore it on exit */
1738         parent_pgrp = tcgetpgrp(0);
1739
1740         command = (char *) xcalloc(BUFSIZ, sizeof(char));
1741
1742         /* don't pay any attention to this signal; it just confuses
1743            things and isn't really meant for shells anyway */
1744         signal(SIGTTOU, SIG_IGN);
1745
1746         while (1) {
1747                 if (!job_list.fg) {
1748                         /* no job is in the foreground */
1749
1750                         /* see if any background processes have exited */
1751                         checkjobs(&job_list);
1752
1753                         if (!next_command) {
1754                                 if (get_command(input, command))
1755                                         break;
1756                                 next_command = command;
1757                         }
1758
1759                         if (expand_arguments(next_command) == FALSE) {
1760                                 free(command);
1761                                 command = (char *) xcalloc(BUFSIZ, sizeof(char));
1762                                 next_command = NULL;
1763                                 continue;
1764                         }
1765
1766                         if (!parse_command(&next_command, &newjob, &inbg) &&
1767                                 newjob.num_progs) {
1768                                 int pipefds[2] = {-1,-1};
1769                                 debug_printf( "job=%p fed to run_command by busy_loop()'\n",
1770                                                 &newjob);
1771                                 run_command(&newjob, inbg, pipefds);
1772                         }
1773                         else {
1774                                 free(command);
1775                                 command = (char *) xcalloc(BUFSIZ, sizeof(char));
1776                                 next_command = NULL;
1777                         }
1778                 } else {
1779                         /* a job is running in the foreground; wait for it */
1780                         i = 0;
1781                         while (!job_list.fg->progs[i].pid ||
1782                                    job_list.fg->progs[i].is_stopped == 1) i++;
1783
1784                         if (waitpid(job_list.fg->progs[i].pid, &status, WUNTRACED)<0)
1785                                 perror_msg_and_die("waitpid(%d)",job_list.fg->progs[i].pid);
1786
1787                         if (WIFEXITED(status) || WIFSIGNALED(status)) {
1788                                 /* the child exited */
1789                                 job_list.fg->running_progs--;
1790                                 job_list.fg->progs[i].pid = 0;
1791
1792 #ifdef BB_FEATURE_SH_ENVIRONMENT
1793                                 last_return_code=WEXITSTATUS(status);
1794                                 debug_printf("'%s' exited -- return code %d\n",
1795                                                 job_list.fg->text, last_return_code);
1796 #endif
1797                                 if (!job_list.fg->running_progs) {
1798                                         /* child exited */
1799                                         remove_job(&job_list, job_list.fg);
1800                                         job_list.fg = NULL;
1801                                 }
1802                         } else {
1803                                 /* the child was stopped */
1804                                 job_list.fg->stopped_progs++;
1805                                 job_list.fg->progs[i].is_stopped = 1;
1806
1807                                 if (job_list.fg->stopped_progs == job_list.fg->running_progs) {
1808                                         printf("\n" JOB_STATUS_FORMAT, job_list.fg->jobid,
1809                                                    "Stopped", job_list.fg->text);
1810                                         job_list.fg = NULL;
1811                                 }
1812                         }
1813
1814                         if (!job_list.fg) {
1815                                 /* move the shell to the foreground */
1816                                 /* suppress messages when run from /linuxrc mag@sysgo.de */
1817                                 if (tcsetpgrp(0, getpid()) && errno != ENOTTY)
1818                                         perror_msg("tcsetpgrp");
1819                         }
1820                 }
1821         }
1822         free(command);
1823
1824         /* return controlling TTY back to parent process group before exiting */
1825         if (tcsetpgrp(0, parent_pgrp))
1826                 perror_msg("tcsetpgrp");
1827
1828         /* return exit status if called with "-c" */
1829         if (input == NULL && WIFEXITED(status))
1830                 return WEXITSTATUS(status);
1831
1832         return 0;
1833 }
1834
1835
1836 #ifdef BB_FEATURE_CLEAN_UP
1837 void free_memory(void)
1838 {
1839         if (cwd)
1840                 free(cwd);
1841         if (local_pending_command)
1842                 free(local_pending_command);
1843
1844         if (job_list.fg && !job_list.fg->running_progs) {
1845                 remove_job(&job_list, job_list.fg);
1846         }
1847 }
1848 #endif
1849
1850
1851 int shell_main(int argc_l, char **argv_l)
1852 {
1853         int opt, interactive=FALSE;
1854         FILE *input = stdin;
1855         argc = argc_l;
1856         argv = argv_l;
1857
1858         /* These variables need re-initializing when recursing */
1859         shell_context = 0;
1860         cwd=NULL;
1861         local_pending_command = NULL;
1862         close_me_head = NULL;
1863         job_list.head = NULL;
1864         job_list.fg = NULL;
1865 #ifdef BB_FEATURE_SH_ENVIRONMENT
1866         last_bg_pid=1;
1867         last_return_code=1;
1868         show_x_trace=FALSE;
1869 #endif
1870
1871         if (argv[0] && argv[0][0] == '-') {
1872                 FILE *prof_input;
1873                 prof_input = fopen("/etc/profile", "r");
1874                 if (!prof_input) {
1875                         printf( "Couldn't open file '/etc/profile'\n");
1876                 } else {
1877                         int tmp_fd = fileno(prof_input);
1878                         mark_open(tmp_fd);
1879                         /* Now run the file */
1880                         busy_loop(prof_input);
1881                         fclose(prof_input);
1882                         mark_closed(tmp_fd);
1883                 }
1884         }
1885
1886         while ((opt = getopt(argc_l, argv_l, "cxi")) > 0) {
1887                 switch (opt) {
1888                         case 'c':
1889                                 input = NULL;
1890                                 if (local_pending_command != 0)
1891                                         error_msg_and_die("multiple -c arguments");
1892                                 local_pending_command = xstrdup(argv[optind]);
1893                                 optind++;
1894                                 argv = argv+optind;
1895                                 break;
1896 #ifdef BB_FEATURE_SH_ENVIRONMENT
1897                         case 'x':
1898                                 show_x_trace = TRUE;
1899                                 break;
1900 #endif
1901                         case 'i':
1902                                 interactive = TRUE;
1903                                 break;
1904                         default:
1905                                 show_usage();
1906                 }
1907         }
1908         /* A shell is interactive if the `-i' flag was given, or if all of
1909          * the following conditions are met:
1910          *        no -c command
1911          *    no arguments remaining or the -s flag given
1912          *    standard input is a terminal
1913          *    standard output is a terminal
1914          *    Refer to Posix.2, the description of the `sh' utility. */
1915         if (argv[optind]==NULL && input==stdin &&
1916                         isatty(fileno(stdin)) && isatty(fileno(stdout))) {
1917                 interactive=TRUE;
1918         }
1919         if (interactive==TRUE) {
1920                 //printf( "optind=%d  argv[optind]='%s'\n", optind, argv[optind]);
1921                 /* Looks like they want an interactive shell */
1922                 printf( "\n\nBusyBox v%s (%s) Built-in shell (lash)\n", BB_VER, BB_BT);
1923                 printf( "Enter 'help' for a list of built-in commands.\n\n");
1924         } else if (local_pending_command==NULL) {
1925                 //printf( "optind=%d  argv[optind]='%s'\n", optind, argv[optind]);
1926                 input = xfopen(argv[optind], "r");
1927                 mark_open(fileno(input));  /* be lazy, never mark this closed */
1928         }
1929
1930         /* initialize the cwd -- this is never freed...*/
1931         cwd=(char*)xmalloc(sizeof(char)*MAX_LINE+1);
1932         getcwd(cwd, sizeof(char)*MAX_LINE);
1933
1934 #ifdef BB_FEATURE_CLEAN_UP
1935         atexit(free_memory);
1936 #endif
1937
1938 #ifdef BB_FEATURE_COMMAND_EDITING
1939         cmdedit_set_initial_prompt();
1940 #else
1941         PS1 = NULL;
1942         PS2 = "> ";
1943 #endif
1944
1945         return (busy_loop(input));
1946 }
1947