shell/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_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
 673         for (i = 0; i < cmd->num_progs; i++) {
 674                 free(cmd->progs[i].argv);
 675                 if (cmd->progs[i].redirects)
 676                         free(cmd->progs[i].redirects);
 677         }
 678         free(cmd->progs);
 679         if (cmd->text)
 680                 free(cmd->text);
 681         free(cmd->cmdbuf);
 682         memset(cmd, 0, sizeof(struct job));
 683 }
 684
 685 /* remove a job from the job_list */
 686 static void remove_job(struct jobset *job_list, struct job *job)
 687 {
 688         struct job *prevjob;
 689
 690         free_job(job);
 691         if (job == job_list->head) {
 692                 job_list->head = job->next;
 693         } else {
 694                 prevjob = job_list->head;
 695                 while (prevjob->next != job)
 696                         prevjob = prevjob->next;
 697                 prevjob->next = job->next;
 698         }
 699
 700         free(job);
 701 }
 702
 703 /* Checks to see if any background processes have exited -- if they
 704    have, figure out why and see if a job has completed */
 705 static void checkjobs(struct jobset *job_list)
 706 {
 707         struct job *job;
 708         pid_t childpid;
 709         int status;
 710         int prognum = 0;
 711
 712         while ((childpid = waitpid(-1, &status, WNOHANG | WUNTRACED)) > 0) {
 713                 for (job = job_list->head; job; job = job->next) {
 714                         prognum = 0;
 715                         while (prognum < job->num_progs &&
 716                                    job->progs[prognum].pid != childpid) prognum++;
 717                         if (prognum < job->num_progs)
 718                                 break;
 719                 }
 720
 721                 /* This happens on backticked commands */
 722                 if(job==NULL)
 723                         return;
 724
 725                 if (WIFEXITED(status) || WIFSIGNALED(status)) {
 726                         /* child exited */
 727                         job->running_progs--;
 728                         job->progs[prognum].pid = 0;
 729
 730                         if (!job->running_progs) {
 731                                 printf(JOB_STATUS_FORMAT, job->jobid, "Done", job->text);
 732                                 remove_job(job_list, job);
 733                         }
 734                 } else {
 735                         /* child stopped */
 736                         job->stopped_progs++;
 737                         job->progs[prognum].is_stopped = 1;
 738
 739                         if (job->stopped_progs == job->num_progs) {
 740                                 printf(JOB_STATUS_FORMAT, job->jobid, "Stopped",
 741                                            job->text);
 742                         }
 743                 }
 744         }
 745
 746         if (childpid == -1 && errno != ECHILD)
 747                 perror_msg("waitpid");
 748 }
 749
 750 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
 751  * and stderr if they are redirected. */
 752 static int setup_redirects(struct child_prog *prog, int squirrel[])
 753 {
 754         int i;
 755         int openfd;
 756         int mode = O_RDONLY;
 757         struct redir_struct *redir = prog->redirects;
 758
 759         for (i = 0; i < prog->num_redirects; i++, redir++) {
 760                 switch (redir->type) {
 761                 case REDIRECT_INPUT:
 762                         mode = O_RDONLY;
 763                         break;
 764                 case REDIRECT_OVERWRITE:
 765                         mode = O_WRONLY | O_CREAT | O_TRUNC;
 766                         break;
 767                 case REDIRECT_APPEND:
 768                         mode = O_WRONLY | O_CREAT | O_APPEND;
 769                         break;
 770                 }
 771
 772                 openfd = open(redir->filename, mode, 0666);
 773                 if (openfd < 0) {
 774                         /* this could get lost if stderr has been redirected, but
 775                            bash and ash both lose it as well (though zsh doesn't!) */
 776                         perror_msg("error opening %s", redir->filename);
 777                         return 1;
 778                 }
 779
 780                 if (openfd != redir->fd) {
 781                         if (squirrel && redir->fd < 3) {
 782                                 squirrel[redir->fd] = dup(redir->fd);
 783                         }
 784                         dup2(openfd, redir->fd);
 785                         close(openfd);
 786                 }
 787         }
 788
 789         return 0;
 790 }
 791
 792 static void restore_redirects(int squirrel[])
 793 {
 794         int i, fd;
 795         for (i=0; i<3; i++) {
 796                 fd = squirrel[i];
 797                 if (fd != -1) {
 798                         /* No error checking.  I sure wouldn't know what
 799                          * to do with an error if I found one! */
 800                         dup2(fd, i);
 801                         close(fd);
 802                 }
 803         }
 804 }
 805
 806 static inline void cmdedit_set_initial_prompt(void)
 807 {
 808 #ifdef BB_FEATURE_SIMPLE_PROMPT
 809         PS1 = NULL;
 810         PS2 = "> ";
 811 #else
 812         PS1 = getenv("PS1");
 813         if(PS1==0) {
 814                 PS1 = "\\w \\$ ";
 815         }
 816         PS2 = getenv("PS2");
 817         if(PS2==0)
 818                 PS2 = "> ";
 819 #endif
 820 }
 821
 822 static inline void setup_prompt_string(char **prompt_str)
 823 {
 824 #ifdef BB_FEATURE_SIMPLE_PROMPT
 825         /* Set up the prompt */
 826         if (shell_context == 0) {
 827                 if (PS1)
 828                         free(PS1);
 829                 PS1=xmalloc(strlen(cwd)+4);
 830                 sprintf(PS1, "%s %s", cwd, ( geteuid() != 0 ) ?  "$ ":"# ");
 831                 *prompt_str = PS1;
 832         } else {
 833                 *prompt_str = PS2;
 834         }
 835 #else
 836         *prompt_str = (shell_context==0)? PS1 : PS2;
 837 #endif
 838 }
 839
 840 static int get_command(FILE * source, char *command)
 841 {
 842         char *prompt_str;
 843
 844         if (source == NULL) {
 845                 if (local_pending_command) {
 846                         /* a command specified (-c option): return it & mark it done */
 847                         strcpy(command, local_pending_command);
 848                         free(local_pending_command);
 849                         local_pending_command = NULL;
 850                         return 0;
 851                 }
 852                 return 1;
 853         }
 854
 855         if (source == stdin) {
 856                 setup_prompt_string(&prompt_str);
 857
 858 #ifdef BB_FEATURE_COMMAND_EDITING
 859                 /*
 860                 ** enable command line editing only while a command line
 861                 ** is actually being read; otherwise, we'll end up bequeathing
 862                 ** atexit() handlers and other unwanted stuff to our
 863                 ** child processes (rob@sysgo.de)
 864                 */
 865                 cmdedit_read_input(prompt_str, command);
 866                 cmdedit_terminate();
 867                 return 0;
 868 #else
 869                 fputs(prompt_str, stdout);
 870 #endif
 871         }
 872
 873         if (!fgets(command, BUFSIZ - 2, source)) {
 874                 if (source == stdin)
 875                         printf("\n");
 876                 return 1;
 877         }
 878
 879         /* remove trailing newline */
 880         chomp(command);
 881
 882         return 0;
 883 }
 884
 885 #ifdef BB_FEATURE_SH_ENVIRONMENT
 886 static char* itoa(register int i)
 887 {
 888         static char a[7]; /* Max 7 ints */
 889         register char *b = a + sizeof(a) - 1;
 890         int   sign = (i < 0);
 891
 892         if (sign)
 893                 i = -i;
 894         *b = 0;
 895         do
 896         {
 897                 *--b = '0' + (i % 10);
 898                 i /= 10;
 899         }
 900         while (i);
 901         if (sign)
 902                 *--b = '-';
 903         return b;
 904 }
 905 #endif
 906
 907 #if defined BB_FEATURE_SH_ENVIRONMENT && ! defined BB_FEATURE_SH_WORDEXP
 908 char * strsep_space( char *string, int * index)
 909 {
 910         char *token, *begin;
 911
 912         begin = string;
 913
 914         /* Short circuit the trivial case */
 915         if ( !string || ! string[*index])
 916                 return NULL;
 917
 918         /* Find the end of the token. */
 919         while( string && string[*index] && !isspace(string[*index]) ) {
 920                 (*index)++;
 921         }
 922
 923         /* Find the end of any whitespace trailing behind
 924          * the token and let that be part of the token */
 925         while( string && string[*index] && isspace(string[*index]) ) {
 926                 (*index)++;
 927         }
 928
 929         if (! string && *index==0) {
 930                 /* Nothing useful was found */
 931                 return NULL;
 932         }
 933
 934         token = xmalloc(*index);
 935         token[*index] = '\0';
 936         strncpy(token, string,  *index);
 937
 938         return token;
 939 }
 940 #endif
 941
 942
 943 static int expand_arguments(char *command)
 944 {
 945 #ifdef BB_FEATURE_SH_ENVIRONMENT
 946         expand_t expand_result;
 947         char *src, *dst, *var;
 948         int index = 0;
 949         int i=0, length, total_length=0, retval;
 950         const char *out_of_space = "out of space during expansion";
 951 #endif
 952
 953         /* get rid of the terminating \n */
 954         chomp(command);
 955
 956         /* Fix up escape sequences to be the Real Thing(tm) */
 957         while( command && command[index]) {
 958                 if (command[index] == '\\') {
 959                         char *tmp = command+index+1;
 960                         command[index+1] = process_escape_sequence(  &tmp );
 961                         memmove(command+index, command+index+1, strlen(command+index));
 962                 }
 963                 index++;
 964         }
 965
 966 #ifdef BB_FEATURE_SH_ENVIRONMENT
 967
 968
 969 #if BB_FEATURE_SH_WORDEXP
 970         /* This first part uses wordexp() which is a wonderful C lib
 971          * function which expands nearly everything.  */
 972         retval = wordexp (command, &expand_result, WRDE_SHOWERR);
 973         if (retval == WRDE_NOSPACE) {
 974                 /* Mem may have been allocated... */
 975                 wordfree (&expand_result);
 976                 error_msg(out_of_space);
 977                 return FALSE;
 978         }
 979         if (retval < 0) {
 980                 /* Some other error.  */
 981                 error_msg("syntax error");
 982                 return FALSE;
 983         }
 984
 985         if (expand_result.we_wordc > 0) {
 986                 /* Convert from char** (one word per string) to a simple char*,
 987                  * but don't overflow command which is BUFSIZ in length */
 988                 *command = '\0';
 989                 while (i < expand_result.we_wordc && total_length < BUFSIZ) {
 990                         length=strlen(expand_result.we_wordv[i])+1;
 991                         if (BUFSIZ-total_length-length <= 0) {
 992                                 error_msg(out_of_space);
 993                                 return FALSE;
 994                         }
 995                         strcat(command+total_length, expand_result.we_wordv[i++]);
 996                         strcat(command+total_length, " ");
 997                         total_length+=length;
 998                 }
 999                 wordfree (&expand_result);
1000         }
1001 #else
1002
1003         /* Ok.  They don't have a recent glibc and they don't have uClibc.  Chances
1004          * are about 100% they don't have wordexp(). So instead the best we can do
1005          * is use glob and then fixup environment variables and such ourselves.
1006          * This is better then nothing, but certainly not perfect */
1007
1008         /* It turns out that glob is very stupid.  We have to feed it one word at a
1009          * time since it can't cope with a full string.  Here we convert command
1010          * (char*) into cmd (char**, one word per string) */
1011         {
1012
1013                 int flags = GLOB_NOCHECK|GLOB_BRACE|GLOB_TILDE;
1014                 char *tmpcmd, *cmd, *cmd_copy;
1015                 /* We need a clean copy, so strsep can mess up the copy while
1016                  * we write stuff into the original (in a minute) */
1017                 cmd = cmd_copy = strdup(command);
1018                 *command = '\0';
1019                 for (index = 0, tmpcmd = cmd;
1020                                 (tmpcmd = strsep_space(cmd, &index)) != NULL; cmd += index, index=0) {
1021                         if (*tmpcmd == '\0')
1022                                 break;
1023                         retval = glob(tmpcmd, flags, NULL, &expand_result);
1024                         free(tmpcmd); /* Free mem allocated by strsep_space */
1025                         if (retval == GLOB_NOSPACE) {
1026                                 /* Mem may have been allocated... */
1027                                 globfree (&expand_result);
1028                                 error_msg(out_of_space);
1029                                 return FALSE;
1030                         } else if (retval != 0) {
1031                                 /* Some other error.  GLOB_NOMATCH shouldn't
1032                                  * happen because of the GLOB_NOCHECK flag in
1033                                  * the glob call. */
1034                                 error_msg("syntax error");
1035                                 return FALSE;
1036                         } else {
1037                         /* Convert from char** (one word per string) to a simple char*,
1038                          * but don't overflow command which is BUFSIZ in length */
1039                                 for (i=0; i < expand_result.gl_pathc; i++) {
1040                                         length=strlen(expand_result.gl_pathv[i])+1;
1041                                         if (BUFSIZ-total_length-length <= 0) {
1042                                                 error_msg(out_of_space);
1043                                                 return FALSE;
1044                                         }
1045                                         strcat(command+total_length, expand_result.gl_pathv[i]);
1046                                         strcat(command+total_length, " ");
1047                                         total_length+=length;
1048                                 }
1049                                 globfree (&expand_result);
1050                         }
1051                 }
1052                 free(cmd_copy);
1053                 trim(command);
1054         }
1055
1056 #endif
1057
1058         /* Now do the shell variable substitutions which
1059          * wordexp can't do for us, namely $? and $! */
1060         src = command;
1061         while((dst = strchr(src,'$')) != NULL){
1062                 var = NULL;
1063                 switch(*(dst+1)) {
1064                         case '?':
1065                                 var = itoa(last_return_code);
1066                                 break;
1067                         case '!':
1068                                 if (last_bg_pid==-1)
1069                                         *(var)='\0';
1070                                 else
1071                                         var = itoa(last_bg_pid);
1072                                 break;
1073                                 /* Everything else like $$, $#, $[0-9], etc should all be
1074                                  * expanded by wordexp(), so we can in theory skip that stuff
1075                                  * here, but just to be on the safe side (i.e. since uClibc
1076                                  * wordexp doesn't do this stuff yet), lets leave it in for
1077                                  * now. */
1078                         case '$':
1079                                 var = itoa(getpid());
1080                                 break;
1081                         case '#':
1082                                 var = itoa(argc-1);
1083                                 break;
1084                         case '0':case '1':case '2':case '3':case '4':
1085                         case '5':case '6':case '7':case '8':case '9':
1086                                 {
1087                                         int index=*(dst + 1)-48;
1088                                         if (index >= argc) {
1089                                                 var='\0';
1090                                         } else {
1091                                                 var = argv[index];
1092                                         }
1093                                 }
1094                                 break;
1095
1096                 }
1097                 if (var) {
1098                         /* a single character construction was found, and
1099                          * already handled in the case statement */
1100                         src=dst+2;
1101                 } else {
1102                         /* Looks like an environment variable */
1103                         char delim_hold;
1104                         int num_skip_chars=1;
1105                         int dstlen = strlen(dst);
1106                         /* Is this a ${foo} type variable? */
1107                         if (dstlen >=2 && *(dst+1) == '{') {
1108                                 src=strchr(dst+1, '}');
1109                                 num_skip_chars=2;
1110                         } else {
1111                                 src=strpbrk(dst+1, " \t~`!$^&*()=|\\[];\"'<>?./");
1112                         }
1113                         if (src == NULL) {
1114                                 src = dst+dstlen;
1115                         }
1116                         delim_hold=*src;
1117                         *src='\0';  /* temporary */
1118                         var = getenv(dst + num_skip_chars);
1119                         *src=delim_hold;
1120                         if (num_skip_chars==2) {
1121                                 src++;
1122                         }
1123                 }
1124                 if (var == NULL) {
1125                         /* Seems we got an un-expandable variable.  So delete it. */
1126                         var = "";
1127                 }
1128                 {
1129                         int subst_len = strlen(var);
1130                         int trail_len = strlen(src);
1131                         if (dst+subst_len+trail_len >= command+BUFSIZ) {
1132                                 error_msg(out_of_space);
1133                                 return FALSE;
1134                         }
1135                         /* Move stuff to the end of the string to accommodate
1136                          * filling the created gap with the new stuff */
1137                         memmove(dst+subst_len, src, trail_len);
1138                         *(dst+subst_len+trail_len)='\0';
1139                         /* Now copy in the new stuff */
1140                         memcpy(dst, var, subst_len);
1141                         src = dst+subst_len;
1142                 }
1143         }
1144
1145 #endif
1146         return TRUE;
1147 }
1148
1149 /* Return cmd->num_progs as 0 if no command is present (e.g. an empty
1150    line). If a valid command is found, command_ptr is set to point to
1151    the beginning of the next command (if the original command had more
1152    then one job associated with it) or NULL if no more commands are
1153    present. */
1154 static int parse_command(char **command_ptr, struct job *job, int *inbg)
1155 {
1156         char *command;
1157         char *return_command = NULL;
1158         char *src, *buf, *chptr;
1159         int argc_l = 0;
1160         int done = 0;
1161         int argv_alloced;
1162         int i;
1163         char quote = '\0';
1164         int count;
1165         struct child_prog *prog;
1166
1167         /* skip leading white space */
1168         while (**command_ptr && isspace(**command_ptr))
1169                 (*command_ptr)++;
1170
1171         /* this handles empty lines or leading '#' characters */
1172         if (!**command_ptr || (**command_ptr == '#')) {
1173                 job->num_progs=0;
1174                 return 0;
1175         }
1176
1177         *inbg = 0;
1178         job->num_progs = 1;
1179         job->progs = xmalloc(sizeof(*job->progs));
1180
1181         /* We set the argv elements to point inside of this string. The
1182            memory is freed by free_job(). Allocate twice the original
1183            length in case we need to quote every single character.
1184
1185            Getting clean memory relieves us of the task of NULL
1186            terminating things and makes the rest of this look a bit
1187            cleaner (though it is, admittedly, a tad less efficient) */
1188         job->cmdbuf = command = xcalloc(2*strlen(*command_ptr) + 1, sizeof(char));
1189         job->text = NULL;
1190
1191         prog = job->progs;
1192         prog->num_redirects = 0;
1193         prog->redirects = NULL;
1194         prog->is_stopped = 0;
1195         prog->family = job;
1196
1197         argv_alloced = 5;
1198         prog->argv = xmalloc(sizeof(*prog->argv) * argv_alloced);
1199         prog->argv[0] = job->cmdbuf;
1200
1201         buf = command;
1202         src = *command_ptr;
1203         while (*src && !done) {
1204                 if (quote == *src) {
1205                         quote = '\0';
1206                 } else if (quote) {
1207                         if (*src == '\\') {
1208                                 src++;
1209                                 if (!*src) {
1210                                         error_msg("character expected after \\");
1211                                         free_job(job);
1212                                         return 1;
1213                                 }
1214
1215                                 /* in shell, "\'" should yield \' */
1216                                 if (*src != quote) {
1217                                         *buf++ = '\\';
1218                                         *buf++ = '\\';
1219                                 }
1220                         } else if (*src == '*' || *src == '?' || *src == '[' ||
1221                                            *src == ']') *buf++ = '\\';
1222                         *buf++ = *src;
1223                 } else if (isspace(*src)) {
1224                         if (*prog->argv[argc_l]) {
1225                                 buf++, argc_l++;
1226                                 /* +1 here leaves room for the NULL which ends argv */
1227                                 if ((argc_l + 1) == argv_alloced) {
1228                                         argv_alloced += 5;
1229                                         prog->argv = xrealloc(prog->argv,
1230                                                                                   sizeof(*prog->argv) *
1231                                                                                   argv_alloced);
1232                                 }
1233                                 prog->argv[argc_l] = buf;
1234                         }
1235                 } else
1236                         switch (*src) {
1237                         case '"':
1238                         case '\'':
1239                                 quote = *src;
1240                                 break;
1241
1242                         case '#':                       /* comment */
1243                                 if (*(src-1)== '$')
1244                                         *buf++ = *src;
1245                                 else
1246                                         done = 1;
1247                                 break;
1248
1249                         case '>':                       /* redirects */
1250                         case '<':
1251                                 i = prog->num_redirects++;
1252                                 prog->redirects = xrealloc(prog->redirects,
1253                                                                                           sizeof(*prog->redirects) *
1254                                                                                           (i + 1));
1255
1256                                 prog->redirects[i].fd = -1;
1257                                 if (buf != prog->argv[argc_l]) {
1258                                         /* the stuff before this character may be the file number
1259                                            being redirected */
1260                                         prog->redirects[i].fd =
1261                                                 strtol(prog->argv[argc_l], &chptr, 10);
1262
1263                                         if (*chptr && *prog->argv[argc_l]) {
1264                                                 buf++, argc_l++;
1265                                                 prog->argv[argc_l] = buf;
1266                                         }
1267                                 }
1268
1269                                 if (prog->redirects[i].fd == -1) {
1270                                         if (*src == '>')
1271                                                 prog->redirects[i].fd = 1;
1272                                         else
1273                                                 prog->redirects[i].fd = 0;
1274                                 }
1275
1276                                 if (*src++ == '>') {
1277                                         if (*src == '>')
1278                                                 prog->redirects[i].type =
1279                                                         REDIRECT_APPEND, src++;
1280                                         else
1281                                                 prog->redirects[i].type = REDIRECT_OVERWRITE;
1282                                 } else {
1283                                         prog->redirects[i].type = REDIRECT_INPUT;
1284                                 }
1285
1286                                 /* This isn't POSIX sh compliant. Oh well. */
1287                                 chptr = src;
1288                                 while (isspace(*chptr))
1289                                         chptr++;
1290
1291                                 if (!*chptr) {
1292                                         error_msg("file name expected after %c", *src);
1293                                         free_job(job);
1294                                         job->num_progs=0;
1295                                         return 1;
1296                                 }
1297
1298                                 prog->redirects[i].filename = buf;
1299                                 while (*chptr && !isspace(*chptr))
1300                                         *buf++ = *chptr++;
1301
1302                                 src = chptr - 1;        /* we src++ later */
1303                                 prog->argv[argc_l] = ++buf;
1304                                 break;
1305
1306                         case '|':                       /* pipe */
1307                                 /* finish this command */
1308                                 if (*prog->argv[argc_l])
1309                                         argc_l++;
1310                                 if (!argc_l) {
1311                                         error_msg("empty command in pipe");
1312                                         free_job(job);
1313                                         job->num_progs=0;
1314                                         return 1;
1315                                 }
1316                                 prog->argv[argc_l] = NULL;
1317
1318                                 /* and start the next */
1319                                 job->num_progs++;
1320                                 job->progs = xrealloc(job->progs,
1321                                                                           sizeof(*job->progs) * job->num_progs);
1322                                 prog = job->progs + (job->num_progs - 1);
1323                                 prog->num_redirects = 0;
1324                                 prog->redirects = NULL;
1325                                 prog->is_stopped = 0;
1326                                 prog->family = job;
1327                                 argc_l = 0;
1328
1329                                 argv_alloced = 5;
1330                                 prog->argv = xmalloc(sizeof(*prog->argv) * argv_alloced);
1331                                 prog->argv[0] = ++buf;
1332
1333                                 src++;
1334                                 while (*src && isspace(*src))
1335                                         src++;
1336
1337                                 if (!*src) {
1338                                         error_msg("empty command in pipe");
1339                                         free_job(job);
1340                                         job->num_progs=0;
1341                                         return 1;
1342                                 }
1343                                 src--;                  /* we'll ++ it at the end of the loop */
1344
1345                                 break;
1346
1347                         case '&':                       /* background */
1348                                 *inbg = 1;
1349                         case ';':                       /* multiple commands */
1350                                 done = 1;
1351                                 return_command = *command_ptr + (src - *command_ptr) + 1;
1352                                 break;
1353
1354 #ifdef BB_FEATURE_SH_BACKTICKS
1355                         case '`':
1356                                 /* Exec a backtick-ed command */
1357                                 /* Besides any previous brokenness, I have not
1358                                  * updated backtick handling for close_me support.
1359                                  * I don't know if it needs it or not.  -- LRD */
1360                                 {
1361                                         char* charptr1=NULL, *charptr2;
1362                                         char* ptr=NULL;
1363                                         struct job *newjob;
1364                                         struct jobset njob_list = { NULL, NULL };
1365                                         int pipefd[2];
1366                                         int size;
1367
1368                                         ptr=strchr(++src, '`');
1369                                         if (ptr==NULL) {
1370                                                 fprintf(stderr, "Unmatched '`' in command\n");
1371                                                 free_job(job);
1372                                                 return 1;
1373                                         }
1374
1375                                         /* Make some space to hold just the backticked command */
1376                                         charptr1 = charptr2 = xmalloc(1+ptr-src);
1377                                         memcpy(charptr1, src, ptr-src);
1378                                         charptr1[ptr-src] = '\0';
1379                                         newjob = xmalloc(sizeof(struct job));
1380                                         newjob->job_list = &njob_list;
1381                                         /* Now parse and run the backticked command */
1382                                         if (!parse_command(&charptr1, newjob, inbg)
1383                                                         && newjob->num_progs) {
1384                                                 pipe(pipefd);
1385                                                 run_command(newjob, 0, pipefd);
1386                                         }
1387                                         checkjobs(job->job_list);
1388                                         free_job(newjob);  /* doesn't actually free newjob,
1389                                                              looks like a memory leak */
1390                                         free(charptr2);
1391
1392                                         /* Make a copy of any stuff left over in the command
1393                                          * line after the second backtick */
1394                                         charptr2 = xmalloc(strlen(ptr)+1);
1395                                         memcpy(charptr2, ptr+1, strlen(ptr));
1396
1397
1398                                         /* Copy the output from the backtick-ed command into the
1399                                          * command line, making extra room as needed  */
1400                                         --src;
1401                                         charptr1 = xmalloc(BUFSIZ);
1402                                         while ( (size=full_read(pipefd[0], charptr1, BUFSIZ-1)) >0) {
1403                                                 int newsize=src - *command_ptr + size + 1 + strlen(charptr2);
1404                                                 if (newsize > BUFSIZ) {
1405                                                         *command_ptr=xrealloc(*command_ptr, newsize);
1406                                                 }
1407                                                 memcpy(src, charptr1, size);
1408                                                 src+=size;
1409                                         }
1410                                         free(charptr1);
1411                                         close(pipefd[0]);
1412                                         if (*(src-1)=='\n')
1413                                                 --src;
1414
1415                                         /* Now paste into the *command_ptr all the stuff
1416                                          * leftover after the second backtick */
1417                                         memcpy(src, charptr2, strlen(charptr2)+1);
1418                                         free(charptr2);
1419
1420                                         /* Now recursively call parse_command to deal with the new
1421                                          * and improved version of the command line with the backtick
1422                                          * results expanded in place... */
1423                                         {
1424                                                 struct jobset *jl=job->job_list;
1425                                                 free_job(job);
1426                                                 job->job_list = jl;
1427                                         }
1428                                         return(parse_command(command_ptr, job, inbg));
1429                                 }
1430                                 break;
1431 #endif // BB_FEATURE_SH_BACKTICKS
1432
1433                         case '\\':
1434                                 src++;
1435                                 if (!*src) {
1436 /* This is currently a little broken... */
1437 #ifdef HANDLE_CONTINUATION_CHARS
1438                                         /* They fed us a continuation char, so continue reading stuff
1439                                          * on the next line, then tack that onto the end of the current
1440                                          * command */
1441                                         char *command;
1442                                         int newsize;
1443                                         printf("erik: found a continue char at EOL...\n");
1444                                         command = (char *) xcalloc(BUFSIZ, sizeof(char));
1445                                         if (get_command(input, command)) {
1446                                                 error_msg("character expected after \\");
1447                                                 free(command);
1448                                                 free_job(job);
1449                                                 return 1;
1450                                         }
1451                                         newsize = strlen(*command_ptr) + strlen(command) + 2;
1452                                         if (newsize > BUFSIZ) {
1453                                                 printf("erik: doing realloc\n");
1454                                                 *command_ptr=xrealloc(*command_ptr, newsize);
1455                                         }
1456                                         printf("erik: A: *command_ptr='%s'\n", *command_ptr);
1457                                         memcpy(--src, command, strlen(command));
1458                                         printf("erik: B: *command_ptr='%s'\n", *command_ptr);
1459                                         free(command);
1460                                         break;
1461 #else
1462                                         error_msg("character expected after \\");
1463                                         free(command);
1464                                         free_job(job);
1465                                         return 1;
1466 #endif
1467                                 }
1468                                 if (*src == '*' || *src == '[' || *src == ']'
1469                                         || *src == '?') *buf++ = '\\';
1470                                 /* fallthrough */
1471                         default:
1472                                 *buf++ = *src;
1473                         }
1474
1475                 src++;
1476         }
1477
1478         if (*prog->argv[argc_l]) {
1479                 argc_l++;
1480         }
1481         if (!argc_l) {
1482                 free_job(job);
1483                 return 0;
1484         }
1485         prog->argv[argc_l] = NULL;
1486
1487         if (!return_command) {
1488                 job->text = xmalloc(strlen(*command_ptr) + 1);
1489                 strcpy(job->text, *command_ptr);
1490         } else {
1491                 /* This leaves any trailing spaces, which is a bit sloppy */
1492                 count = return_command - *command_ptr;
1493                 job->text = xmalloc(count + 1);
1494                 strncpy(job->text, *command_ptr, count);
1495                 job->text[count] = '\0';
1496         }
1497
1498         *command_ptr = return_command;
1499
1500         return 0;
1501 }
1502
1503 /* Run the child_prog, no matter what kind of command it uses.
1504  */
1505 static int pseudo_exec(struct child_prog *child)
1506 {
1507         struct built_in_command *x;
1508 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
1509         char *name;
1510 #endif
1511
1512         /* Check if the command matches any of the non-forking builtins.
1513          * Depending on context, this might be redundant.  But it's
1514          * easier to waste a few CPU cycles than it is to figure out
1515          * if this is one of those cases.
1516          */
1517         for (x = bltins; x->cmd; x++) {
1518                 if (strcmp(child->argv[0], x->cmd) == 0 ) {
1519                         exit(x->function(child));
1520                 }
1521         }
1522
1523         /* Check if the command matches any of the forking builtins. */
1524         for (x = bltins_forking; x->cmd; x++) {
1525                 if (strcmp(child->argv[0], x->cmd) == 0) {
1526                         applet_name=x->cmd;
1527                         exit (x->function(child));
1528                 }
1529         }
1530 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
1531         /* Check if the command matches any busybox internal
1532          * commands ("applets") here.  Following discussions from
1533          * November 2000 on busybox@opensource.lineo.com, don't use
1534          * get_last_path_component().  This way explicit (with
1535          * slashes) filenames will never be interpreted as an
1536          * applet, just like with builtins.  This way the user can
1537          * override an applet with an explicit filename reference.
1538          * The only downside to this change is that an explicit
1539          * /bin/foo invocation will fork and exec /bin/foo, even if
1540          * /bin/foo is a symlink to busybox.
1541          */
1542         name = child->argv[0];
1543
1544 #ifdef BB_FEATURE_SH_APPLETS_ALWAYS_WIN
1545         /* If you enable BB_FEATURE_SH_APPLETS_ALWAYS_WIN, then
1546          * if you run /bin/cat, it will use BusyBox cat even if
1547          * /bin/cat exists on the filesystem and is _not_ busybox.
1548          * Some systems want this, others do not.  Choose wisely.  :-)
1549          */
1550         name = get_last_path_component(name);
1551 #endif
1552
1553         {
1554             char** argv=child->argv;
1555             int argc_l;
1556             for(argc_l=0;*argv!=NULL; argv++, argc_l++);
1557             optind = 1;
1558             run_applet_by_name(name, argc_l, child->argv);
1559         }
1560 #endif
1561
1562         execvp(child->argv[0], child->argv);
1563         perror_msg_and_die("%s", child->argv[0]);
1564 }
1565
1566 static void insert_job(struct job *newjob, int inbg)
1567 {
1568         struct job *thejob;
1569         struct jobset *job_list=newjob->job_list;
1570
1571         /* find the ID for thejob to use */
1572         newjob->jobid = 1;
1573         for (thejob = job_list->head; thejob; thejob = thejob->next)
1574                 if (thejob->jobid >= newjob->jobid)
1575                         newjob->jobid = thejob->jobid + 1;
1576
1577         /* add thejob to the list of running jobs */
1578         if (!job_list->head) {
1579                 thejob = job_list->head = xmalloc(sizeof(*thejob));
1580         } else {
1581                 for (thejob = job_list->head; thejob->next; thejob = thejob->next) /* nothing */;
1582                 thejob->next = xmalloc(sizeof(*thejob));
1583                 thejob = thejob->next;
1584         }
1585
1586         *thejob = *newjob;   /* physically copy the struct job */
1587         thejob->next = NULL;
1588         thejob->running_progs = thejob->num_progs;
1589         thejob->stopped_progs = 0;
1590
1591         if (inbg) {
1592                 /* we don't wait for background thejobs to return -- append it
1593                    to the list of backgrounded thejobs and leave it alone */
1594                 printf("[%d] %d\n", thejob->jobid,
1595                            newjob->progs[newjob->num_progs - 1].pid);
1596 #ifdef BB_FEATURE_SH_ENVIRONMENT
1597                 last_bg_pid=newjob->progs[newjob->num_progs - 1].pid;
1598 #endif
1599         } else {
1600                 newjob->job_list->fg = thejob;
1601
1602                 /* move the new process group into the foreground */
1603                 /* suppress messages when run from /linuxrc mag@sysgo.de */
1604                 if (tcsetpgrp(0, newjob->pgrp) && errno != ENOTTY)
1605                         perror_msg("tcsetpgrp");
1606         }
1607 }
1608
1609 static int run_command(struct job *newjob, int inbg, int outpipe[2])
1610 {
1611         /* struct job *thejob; */
1612         int i;
1613         int nextin, nextout;
1614         int pipefds[2];                         /* pipefd[0] is for reading */
1615         struct built_in_command *x;
1616         struct child_prog *child;
1617
1618         nextin = 0, nextout = 1;
1619         for (i = 0; i < newjob->num_progs; i++) {
1620                 child = & (newjob->progs[i]);
1621
1622                 if ((i + 1) < newjob->num_progs) {
1623                         if (pipe(pipefds)<0) perror_msg_and_die("pipe");
1624                         nextout = pipefds[1];
1625                 } else {
1626                         if (outpipe[1]!=-1) {
1627                                 nextout = outpipe[1];
1628                         } else {
1629                                 nextout = 1;
1630                         }
1631                 }
1632
1633 #ifdef BB_FEATURE_SH_ENVIRONMENT
1634                 if (show_x_trace==TRUE) {
1635                         int j;
1636                         fputc('+', stderr);
1637                         for (j = 0; child->argv[j]; j++) {
1638                                 fputc(' ', stderr);
1639                                 fputs(child->argv[j], stderr);
1640                         }
1641                         fputc('\n', stderr);
1642                 }
1643 #endif
1644
1645                 /* Check if the command matches any non-forking builtins,
1646                  * but only if this is a simple command.
1647                  * Non-forking builtins within pipes have to fork anyway,
1648                  * and are handled in pseudo_exec.  "echo foo | read bar"
1649                  * is doomed to failure, and doesn't work on bash, either.
1650                  */
1651                 if (newjob->num_progs == 1) {
1652                         for (x = bltins; x->cmd; x++) {
1653                                 if (strcmp(child->argv[0], x->cmd) == 0 ) {
1654                                         int squirrel[] = {-1, -1, -1};
1655                                         int rcode;
1656                                         setup_redirects(child, squirrel);
1657                                         rcode = x->function(child);
1658                                         restore_redirects(squirrel);
1659                                         return rcode;
1660                                 }
1661                         }
1662                 }
1663
1664                 if (!(child->pid = fork())) {
1665                         signal(SIGTTOU, SIG_DFL);
1666
1667                         close_all();
1668
1669                         if (outpipe[1]!=-1) {
1670                                 close(outpipe[0]);
1671                         }
1672                         if (nextin != 0) {
1673                                 dup2(nextin, 0);
1674                                 close(nextin);
1675                         }
1676
1677                         if (nextout != 1) {
1678                                 dup2(nextout, 1);
1679                                 dup2(nextout, 2);  /* Really? */
1680                                 close(nextout);
1681                                 close(pipefds[0]);
1682                         }
1683
1684                         /* explicit redirects override pipes */
1685                         setup_redirects(child,NULL);
1686
1687                         pseudo_exec(child);
1688                 }
1689                 if (outpipe[1]!=-1) {
1690                         close(outpipe[1]);
1691                 }
1692
1693                 /* put our child in the process group whose leader is the
1694                    first process in this pipe */
1695                 setpgid(child->pid, newjob->progs[0].pid);
1696                 if (nextin != 0)
1697                         close(nextin);
1698                 if (nextout != 1)
1699                         close(nextout);
1700
1701                 /* If there isn't another process, nextin is garbage
1702                    but it doesn't matter */
1703                 nextin = pipefds[0];
1704         }
1705
1706         newjob->pgrp = newjob->progs[0].pid;
1707
1708         insert_job(newjob, inbg);
1709
1710         return 0;
1711 }
1712
1713 static int busy_loop(FILE * input)
1714 {
1715         char *command;
1716         char *next_command = NULL;
1717         struct job newjob;
1718         pid_t  parent_pgrp;
1719         int i;
1720         int inbg;
1721         int status;
1722         newjob.job_list = &job_list;
1723         newjob.job_context = DEFAULT_CONTEXT;
1724
1725         /* save current owner of TTY so we can restore it on exit */
1726         parent_pgrp = tcgetpgrp(0);
1727
1728         command = (char *) xcalloc(BUFSIZ, sizeof(char));
1729
1730         /* don't pay any attention to this signal; it just confuses
1731            things and isn't really meant for shells anyway */
1732         signal(SIGTTOU, SIG_IGN);
1733
1734         while (1) {
1735                 if (!job_list.fg) {
1736                         /* no job is in the foreground */
1737
1738                         /* see if any background processes have exited */
1739                         checkjobs(&job_list);
1740
1741                         if (!next_command) {
1742                                 if (get_command(input, command))
1743                                         break;
1744                                 next_command = command;
1745                         }
1746
1747                         if (expand_arguments(next_command) == FALSE) {
1748                                 free(command);
1749                                 command = (char *) xcalloc(BUFSIZ, sizeof(char));
1750                                 next_command = NULL;
1751                                 continue;
1752                         }
1753
1754                         if (!parse_command(&next_command, &newjob, &inbg) &&
1755                                 newjob.num_progs) {
1756                                 int pipefds[2] = {-1,-1};
1757                                 debug_printf( "job=%p fed to run_command by busy_loop()'\n",
1758                                                 &newjob);
1759                                 run_command(&newjob, inbg, pipefds);
1760                         }
1761                         else {
1762                                 free(command);
1763                                 command = (char *) xcalloc(BUFSIZ, sizeof(char));
1764                                 next_command = NULL;
1765                         }
1766                 } else {
1767                         /* a job is running in the foreground; wait for it */
1768                         i = 0;
1769                         while (!job_list.fg->progs[i].pid ||
1770                                    job_list.fg->progs[i].is_stopped == 1) i++;
1771
1772                         if (waitpid(job_list.fg->progs[i].pid, &status, WUNTRACED)<0)
1773                                 perror_msg_and_die("waitpid(%d)",job_list.fg->progs[i].pid);
1774
1775                         if (WIFEXITED(status) || WIFSIGNALED(status)) {
1776                                 /* the child exited */
1777                                 job_list.fg->running_progs--;
1778                                 job_list.fg->progs[i].pid = 0;
1779
1780 #ifdef BB_FEATURE_SH_ENVIRONMENT
1781                                 last_return_code=WEXITSTATUS(status);
1782                                 debug_printf("'%s' exited -- return code %d\n",
1783                                                 job_list.fg->text, last_return_code);
1784 #endif
1785                                 if (!job_list.fg->running_progs) {
1786                                         /* child exited */
1787                                         remove_job(&job_list, job_list.fg);
1788                                         job_list.fg = NULL;
1789                                 }
1790                         } else {
1791                                 /* the child was stopped */
1792                                 job_list.fg->stopped_progs++;
1793                                 job_list.fg->progs[i].is_stopped = 1;
1794
1795                                 if (job_list.fg->stopped_progs == job_list.fg->running_progs) {
1796                                         printf("\n" JOB_STATUS_FORMAT, job_list.fg->jobid,
1797                                                    "Stopped", job_list.fg->text);
1798                                         job_list.fg = NULL;
1799                                 }
1800                         }
1801
1802                         if (!job_list.fg) {
1803                                 /* move the shell to the foreground */
1804                                 /* suppress messages when run from /linuxrc mag@sysgo.de */
1805                                 if (tcsetpgrp(0, getpid()) && errno != ENOTTY)
1806                                         perror_msg("tcsetpgrp");
1807                         }
1808                 }
1809         }
1810         free(command);
1811
1812         /* return controlling TTY back to parent process group before exiting */
1813         if (tcsetpgrp(0, parent_pgrp))
1814                 perror_msg("tcsetpgrp");
1815
1816         /* return exit status if called with "-c" */
1817         if (input == NULL && WIFEXITED(status))
1818                 return WEXITSTATUS(status);
1819
1820         return 0;
1821 }
1822
1823
1824 #ifdef BB_FEATURE_CLEAN_UP
1825 void free_memory(void)
1826 {
1827         if (cwd)
1828                 free(cwd);
1829         if (local_pending_command)
1830                 free(local_pending_command);
1831
1832         if (job_list.fg && !job_list.fg->running_progs) {
1833                 remove_job(&job_list, job_list.fg);
1834         }
1835 }
1836 #endif
1837
1838
1839 int shell_main(int argc_l, char **argv_l)
1840 {
1841         int opt, interactive=FALSE;
1842         FILE *input = stdin;
1843         argc = argc_l;
1844         argv = argv_l;
1845
1846         /* These variables need re-initializing when recursing */
1847         shell_context = 0;
1848         cwd=NULL;
1849         local_pending_command = NULL;
1850         close_me_head = NULL;
1851         job_list.head = NULL;
1852         job_list.fg = NULL;
1853 #ifdef BB_FEATURE_SH_ENVIRONMENT
1854         last_bg_pid=1;
1855         last_return_code=1;
1856         show_x_trace=FALSE;
1857 #endif
1858
1859         if (argv[0] && argv[0][0] == '-') {
1860                 FILE *prof_input;
1861                 prof_input = fopen("/etc/profile", "r");
1862                 if (!prof_input) {
1863                         printf( "Couldn't open file '/etc/profile'\n");
1864                 } else {
1865                         int tmp_fd = fileno(prof_input);
1866                         mark_open(tmp_fd);
1867                         /* Now run the file */
1868                         busy_loop(prof_input);
1869                         fclose(prof_input);
1870                         mark_closed(tmp_fd);
1871                 }
1872         }
1873
1874         while ((opt = getopt(argc_l, argv_l, "cxi")) > 0) {
1875                 switch (opt) {
1876                         case 'c':
1877                                 input = NULL;
1878                                 if (local_pending_command != 0)
1879                                         error_msg_and_die("multiple -c arguments");
1880                                 local_pending_command = xstrdup(argv[optind]);
1881                                 optind++;
1882                                 argv = argv+optind;
1883                                 break;
1884 #ifdef BB_FEATURE_SH_ENVIRONMENT
1885                         case 'x':
1886                                 show_x_trace = TRUE;
1887                                 break;
1888 #endif
1889                         case 'i':
1890                                 interactive = TRUE;
1891                                 break;
1892                         default:
1893                                 show_usage();
1894                 }
1895         }
1896         /* A shell is interactive if the `-i' flag was given, or if all of
1897          * the following conditions are met:
1898          *        no -c command
1899          *    no arguments remaining or the -s flag given
1900          *    standard input is a terminal
1901          *    standard output is a terminal
1902          *    Refer to Posix.2, the description of the `sh' utility. */
1903         if (argv[optind]==NULL && input==stdin &&
1904                         isatty(fileno(stdin)) && isatty(fileno(stdout))) {
1905                 interactive=TRUE;
1906         }
1907         if (interactive==TRUE) {
1908                 //printf( "optind=%d  argv[optind]='%s'\n", optind, argv[optind]);
1909                 /* Looks like they want an interactive shell */
1910                 printf( "\n\nBusyBox v%s (%s) Built-in shell (lash)\n", BB_VER, BB_BT);
1911                 printf( "Enter 'help' for a list of built-in commands.\n\n");
1912         } else if (local_pending_command==NULL) {
1913                 //printf( "optind=%d  argv[optind]='%s'\n", optind, argv[optind]);
1914                 input = xfopen(argv[optind], "r");
1915                 mark_open(fileno(input));  /* be lazy, never mark this closed */
1916         }
1917
1918         /* initialize the cwd -- this is never freed...*/
1919         cwd=(char*)xmalloc(sizeof(char)*MAX_LINE+1);
1920         getcwd(cwd, sizeof(char)*MAX_LINE);
1921
1922 #ifdef BB_FEATURE_CLEAN_UP
1923         atexit(free_memory);
1924 #endif
1925
1926 #ifdef BB_FEATURE_COMMAND_EDITING
1927         cmdedit_set_initial_prompt();
1928 #else
1929         PS1 = NULL;
1930         PS2 = "> ";
1931 #endif
1932
1933         return (busy_loop(input));
1934 }
1935