aboutsummaryrefslogtreecommitdiff
path: root/sh.c
blob: 9b3435304926289db4301c2ccd7c781a7e63361c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
/* vi: set sw=4 ts=4: */
/*
 * lash -- the BusyBox Lame-Ass SHell
 *
 * Copyright (C) 2000 by Lineo, inc.
 * Written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>
 *
 * Based in part on ladsh.c by Michael K. Johnson and Erik W. Troan, which is
 * under the following liberal license: "We have placed this source code in the
 * public domain. Use it in any project, free or commercial."
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */

#include "internal.h"
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <glob.h>
#include <signal.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/wait.h>
#include <unistd.h>
#ifdef BB_FEATURE_SH_COMMAND_EDITING
#include "cmdedit.h"
#endif

#define MAX_READ	128	/* size of input buffer for `read' builtin */
#define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"


enum redirectionType { REDIRECT_INPUT, REDIRECT_OVERWRITE,
	REDIRECT_APPEND
};

struct jobSet {
	struct job *head;			/* head of list of running jobs */
	struct job *fg;				/* current foreground job */
};

struct redirectionSpecifier {
	enum redirectionType type;	/* type of redirection */
	int fd;						/* file descriptor being redirected */
	char *filename;				/* file to redirect fd to */
};

struct childProgram {
	pid_t pid;					/* 0 if exited */
	char **argv;				/* program name and arguments */
	int numRedirections;		/* elements in redirection array */
	struct redirectionSpecifier *redirections;	/* I/O redirections */
	glob_t globResult;			/* result of parameter globbing */
	int freeGlob;				/* should we globfree(&globResult)? */
	int isStopped;				/* is the program currently running? */
};

struct job {
	int jobId;					/* job number */
	int numProgs;				/* total number of programs in job */
	int runningProgs;			/* number of programs running */
	char *text;					/* name of job */
	char *cmdBuf;				/* buffer various argv's point into */
	pid_t pgrp;					/* process group ID for the job */
	struct childProgram *progs;	/* array of programs in job */
	struct job *next;			/* to track background commands */
	int stoppedProgs;			/* number of programs alive, but stopped */
};

struct builtInCommand {
	char *cmd;					/* name */
	char *descr;				/* description */
	char *usage;				/* usage */
	int (*function) (struct job *, struct jobSet * jobList);	/* function ptr */
};

/* function prototypes for builtins */
static int builtin_cd(struct job *cmd, struct jobSet *junk);
static int builtin_env(struct job *dummy, struct jobSet *junk);
static int builtin_exit(struct job *cmd, struct jobSet *junk);
static int builtin_fg_bg(struct job *cmd, struct jobSet *jobList);
static int builtin_help(struct job *cmd, struct jobSet *junk);
static int builtin_jobs(struct job *dummy, struct jobSet *jobList);
static int builtin_pwd(struct job *dummy, struct jobSet *junk);
static int builtin_export(struct job *cmd, struct jobSet *junk);
static int builtin_source(struct job *cmd, struct jobSet *jobList);
static int builtin_unset(struct job *cmd, struct jobSet *junk);
static int builtin_read(struct job *cmd, struct jobSet *junk);


/* function prototypes for shell stuff */
static void checkJobs(struct jobSet *jobList);
static int getCommand(FILE * source, char *command);
static int parseCommand(char **commandPtr, struct job *job, struct jobSet *jobList, int *isBg);
static int setupRedirections(struct childProgram *prog);
static int runCommand(struct job *newJob, struct jobSet *jobList, int inBg);
static int busy_loop(FILE * input);


/* Table of built-in functions (these are non-forking builtins, meaning they
 * can change global variables in the parent shell process but they will not
 * work with pipes and redirects; 'unset foo | whatever' will not work) */
static struct builtInCommand bltins[] = {
	{"bg", "Resume a job in the background", "bg [%%job]", builtin_fg_bg},
	{"cd", "Change working directory", "cd [dir]", builtin_cd},
	{"exit", "Exit from shell()", "exit", builtin_exit},
	{"fg", "Bring job into the foreground", "fg [%%job]", builtin_fg_bg},
	{"jobs", "Lists the active jobs", "jobs", builtin_jobs},
	{"export", "Set environment variable", "export [VAR=value]", builtin_export},
	{"unset", "Unset environment variable", "unset VAR", builtin_unset},
	{"read", "Input environment variable", "read [VAR]", builtin_read},
	{NULL, NULL, NULL, NULL}
};

/* Table of forking built-in functions (things that fork cannot change global
 * variables in the parent process, such as the current working directory) */
static struct builtInCommand bltins_forking[] = {
	{"env", "Print all environment variables", "env", builtin_env},
	{"pwd", "Print current directory", "pwd", builtin_pwd},
	{".", "Source-in and run commands in a file", ". filename", builtin_source},
	{"help", "List shell built-in commands", "help", builtin_help},
	{NULL, NULL, NULL, NULL}
};

static char *prompt = "# ";
static char *cwd = NULL;
static char *local_pending_command = NULL;

#ifdef BB_FEATURE_SH_COMMAND_EDITING
void win_changed(int junk)
{
	struct winsize win = { 0, 0, 0, 0 };
	ioctl(0, TIOCGWINSZ, &win);
	if (win.ws_col > 0) {
		cmdedit_setwidth( win.ws_col - 1);
	}
}
#endif


/* built-in 'cd <path>' handler */
static int builtin_cd(struct job *cmd, struct jobSet *junk)
{
	char *newdir;

	if (!cmd->progs[0].argv[1] == 1)
		newdir = getenv("HOME");
	else
		newdir = cmd->progs[0].argv[1];
	if (chdir(newdir)) {
		printf("cd: %s: %s\n", newdir, strerror(errno));
		return FALSE;
	}
	getcwd(cwd, sizeof(cwd));

	return TRUE;
}

/* built-in 'env' handler */
static int builtin_env(struct job *dummy, struct jobSet *junk)
{
	char **e;

	for (e = environ; *e; e++) {
		fprintf(stdout, "%s\n", *e);
	}
	return (0);
}

/* built-in 'exit' handler */
static int builtin_exit(struct job *cmd, struct jobSet *junk)
{
	if (!cmd->progs[0].argv[1] == 1)
		exit TRUE;

	return(atoi(cmd->progs[0].argv[1]));
}

/* built-in 'fg' and 'bg' handler */
static int builtin_fg_bg(struct job *cmd, struct jobSet *jobList)
{
	int i, jobNum;
	struct job *job=NULL;

	if (!jobList->head) {
		if (!cmd->progs[0].argv[1] || cmd->progs[0].argv[2]) {
			errorMsg("%s: exactly one argument is expected\n",
					cmd->progs[0].argv[0]);
			return FALSE;
		}
		if (sscanf(cmd->progs[0].argv[1], "%%%d", &jobNum) != 1) {
			errorMsg("%s: bad argument '%s'\n",
					cmd->progs[0].argv[0], cmd->progs[0].argv[1]);
			return FALSE;
			for (job = jobList->head; job; job = job->next) {
				if (job->jobId == jobNum) {
					break;
				}
			}
		}
	} else {
		job = jobList->head;
	}

	if (!job) {
		errorMsg("%s: unknown job %d\n",
				cmd->progs[0].argv[0], jobNum);
		return FALSE;
	}

	if (*cmd->progs[0].argv[0] == 'f') {
		/* Make this job the foreground job */
		/* suppress messages when run from /linuxrc mag@sysgo.de */
		if (tcsetpgrp(0, job->pgrp) && errno != ENOTTY)
			perror("tcsetpgrp"); 
		jobList->fg = job;
	}

	/* Restart the processes in the job */
	for (i = 0; i < job->numProgs; i++)
		job->progs[i].isStopped = 0;

	kill(-job->pgrp, SIGCONT);

	job->stoppedProgs = 0;

	return TRUE;
}

/* built-in 'help' handler */
static int builtin_help(struct job *dummy, struct jobSet *junk)
{
	struct builtInCommand *x;

	fprintf(stdout, "\nBuilt-in commands:\n");
	fprintf(stdout, "-------------------\n");
	for (x = bltins; x->cmd; x++) {
		fprintf(stdout, "%s\t%s\n", x->cmd, x->descr);
	}
	for (x = bltins_forking; x->cmd; x++) {
		fprintf(stdout, "%s\t%s\n", x->cmd, x->descr);
	}
	fprintf(stdout, "\n\n");
	return TRUE;
}

/* built-in 'jobs' handler */
static int builtin_jobs(struct job *dummy, struct jobSet *jobList)
{
	struct job *job;
	char *statusString;

	for (job = jobList->head; job; job = job->next) {
		if (job->runningProgs == job->stoppedProgs)
			statusString = "Stopped";
		else
			statusString = "Running";

		printf(JOB_STATUS_FORMAT, job->jobId, statusString, job->text);
	}
	return TRUE;
}


/* built-in 'pwd' handler */
static int builtin_pwd(struct job *dummy, struct jobSet *junk)
{
	getcwd(cwd, sizeof(cwd));
	fprintf(stdout, "%s\n", cwd);
	return TRUE;
}

/* built-in 'export VAR=value' handler */
static int builtin_export(struct job *cmd, struct jobSet *junk)
{
	int res;

	if (!cmd->progs[0].argv[1] == 1) {
		return (builtin_env(cmd, junk));
	}
	res = putenv(cmd->progs[0].argv[1]);
	if (res)
		fprintf(stdout, "export: %s\n", strerror(errno));
	return (res);
}

/* built-in 'read VAR' handler */
static int builtin_read(struct job *cmd, struct jobSet *junk)
{
	int res = 0, len, newlen;
	char *s;
	char string[MAX_READ];

	if (cmd->progs[0].argv[1]) {
		/* argument (VAR) given: put "VAR=" into buffer */
		strcpy(string, cmd->progs[0].argv[1]);
		len = strlen(string);
		string[len++] = '=';
		string[len]   = '\0';
		fgets(&string[len], sizeof(string) - len, stdin);	/* read string */
		newlen = strlen(string);
		if(newlen > len)
			string[--newlen] = '\0';	/* chomp trailing newline */
		/*
		** string should now contain "VAR=<value>"
		** copy it (putenv() won't do that, so we must make sure
		** the string resides in a static buffer!)
		*/
		res = -1;
		if((s = strdup(string)))
			res = putenv(s);
		if (res)
			fprintf(stdout, "read: %s\n", strerror(errno));
	}
	else
		fgets(string, sizeof(string), stdin);

	return (res);
}

/* Built-in '.' handler (read-in and execute commands from file) */
static int builtin_source(struct job *cmd, struct jobSet *junk)
{
	FILE *input;
	int status;

	if (!cmd->progs[0].argv[1] == 1)
		return FALSE;

	input = fopen(cmd->progs[0].argv[1], "r");
	if (!input) {
		fprintf(stdout, "Couldn't open file '%s'\n",
				cmd->progs[0].argv[1]);
		return FALSE;
	}

	/* Now run the file */
	status = busy_loop(input);
	return (status);
}

/* built-in 'unset VAR' handler */
static int builtin_unset(struct job *cmd, struct jobSet *junk)
{
	if (!cmd->progs[0].argv[1] == 1) {
		fprintf(stdout, "unset: parameter required.\n");
		return FALSE;
	}
	unsetenv(cmd->progs[0].argv[1]);
	return TRUE;
}

/* free up all memory from a job */
static void freeJob(struct job *cmd)
{
	int i;

	for (i = 0; i < cmd->numProgs; i++) {
		free(cmd->progs[i].argv);
		if (cmd->progs[i].redirections)
			free(cmd->progs[i].redirections);
		if (cmd->progs[i].freeGlob)
			globfree(&cmd->progs[i].globResult);
	}
	free(cmd->progs);
	if (cmd->text)
		free(cmd->text);
	free(cmd->cmdBuf);
	memset(cmd, 0, sizeof(struct job));
}

/* remove a job from the jobList */
static void removeJob(struct jobSet *jobList, struct job *job)
{
	struct job *prevJob;

	freeJob(job);
	if (job == jobList->head) {
		jobList->head = job->next;
	} else {
		prevJob = jobList->head;
		while (prevJob->next != job)
			prevJob = prevJob->next;
		prevJob->next = job->next;
	}

	free(job);
}

/* Checks to see if any background processes have exited -- if they 
   have, figure out why and see if a job has completed */
static void checkJobs(struct jobSet *jobList)
{
	struct job *job;
	pid_t childpid;
	int status;
	int progNum = 0;

	while ((childpid = waitpid(-1, &status, WNOHANG | WUNTRACED)) > 0) {
		for (job = jobList->head; job; job = job->next) {
			progNum = 0;
			while (progNum < job->numProgs &&
				   job->progs[progNum].pid != childpid) progNum++;
			if (progNum < job->numProgs)
				break;
		}

		if (WIFEXITED(status) || WIFSIGNALED(status)) {
			/* child exited */
			job->runningProgs--;
			job->progs[progNum].pid = 0;

			if (!job->runningProgs) {
				printf(JOB_STATUS_FORMAT, job->jobId, "Done", job->text);
				removeJob(jobList, job);
			}
		} else {
			/* child stopped */
			job->stoppedProgs++;
			job->progs[progNum].isStopped = 1;

			if (job->stoppedProgs == job->numProgs) {
				printf(JOB_STATUS_FORMAT, job->jobId, "Stopped",
					   job->text);
			}
		}
	}

	if (childpid == -1 && errno != ECHILD)
		perror("waitpid");
}

static int getCommand(FILE * source, char *command)
{
	if (source == NULL) {
		if (local_pending_command) {
			/* a command specified (-c option): return it & mark it done */
			strcpy(command, local_pending_command);
			free(local_pending_command);
			local_pending_command = NULL;
			return 0;
		}
		return 1;
	}

	if (source == stdin) {
#ifdef BB_FEATURE_SH_COMMAND_EDITING
		int len;
		char *promptStr;
		len=fprintf(stdout, "%s %s", cwd, prompt);
		fflush(stdout);
		promptStr=(char*)xmalloc(sizeof(char)*(len+1));
		sprintf(promptStr, "%s %s", cwd, prompt);
		cmdedit_read_input(promptStr, command);
		free( promptStr);
		return 0;
#else
		fprintf(stdout, "%s %s", cwd, prompt);
		fflush(stdout);
#endif
	}

	if (!fgets(command, BUFSIZ - 2, source)) {
		if (source == stdin)
			printf("\n");
		return 1;
	}

	/* remove trailing newline */
	command[strlen(command) - 1] = '\0';

	return 0;
}

static void globLastArgument(struct childProgram *prog, int *argcPtr,
							 int *argcAllocedPtr)
{
	int argc = *argcPtr;
	int argcAlloced = *argcAllocedPtr;
	int rc;
	int flags;
	int i;
	char *src, *dst, *var;

	if (argc > 1) {				/* cmd->globResult is already initialized */
		flags = GLOB_APPEND;
		i = prog->globResult.gl_pathc;
	} else {
		prog->freeGlob = 1;
		flags = 0;
		i = 0;
	}
	/* do shell variable substitution */
	if(*prog->argv[argc - 1] == '$' && (var = getenv(prog->argv[argc - 1] + 1)))
		prog->argv[argc - 1] = var;

	rc = glob(prog->argv[argc - 1], flags, NULL, &prog->globResult);
	if (rc == GLOB_NOSPACE) {
		errorMsg("out of space during glob operation\n");
		return;
	} else if (rc == GLOB_NOMATCH ||
			   (!rc && (prog->globResult.gl_pathc - i) == 1 &&
				!strcmp(prog->argv[argc - 1],
						prog->globResult.gl_pathv[i]))) {
		/* we need to remove whatever \ quoting is still present */
		src = dst = prog->argv[argc - 1];
		while (*src) {
			if (*src != '\\')
				*dst++ = *src;
			src++;
		}
		*dst = '\0';
	} else if (!rc) {
		argcAlloced += (prog->globResult.gl_pathc - i);
		prog->argv =
			realloc(prog->argv, argcAlloced * sizeof(*prog->argv));
		memcpy(prog->argv + (argc - 1), prog->globResult.gl_pathv + i,
			   sizeof(*(prog->argv)) * (prog->globResult.gl_pathc - i));
		argc += (prog->globResult.gl_pathc - i - 1);
	}

	*argcAllocedPtr = argcAlloced;
	*argcPtr = argc;
}

/* Return cmd->numProgs as 0 if no command is present (e.g. an empty
   line). If a valid command is found, commandPtr is set to point to
   the beginning of the next command (if the original command had more 
   then one job associated with it) or NULL if no more commands are 
   present. */
static int parseCommand(char **commandPtr, struct job *job, struct jobSet *jobList, int *isBg)
{
	char *command;
	char *returnCommand = NULL;
	char *src, *buf, *chptr;
	int argc = 0;
	int done = 0;
	int argvAlloced;
	int i;
	char quote = '\0';
	int count;
	struct childProgram *prog;

	/* skip leading white space */
	while (**commandPtr && isspace(**commandPtr))
		(*commandPtr)++;

	/* this handles empty lines or leading '#' characters */
	if (!**commandPtr || (**commandPtr == '#')) {
		job->numProgs=0;
		return 0;
	}

	*isBg = 0;
	job->numProgs = 1;
	job->progs = xmalloc(sizeof(*job->progs));

	/* We set the argv elements to point inside of this string. The 
	   memory is freed by freeJob(). Allocate twice the original
	   length in case we need to quote every single character.

	   Getting clean memory relieves us of the task of NULL 
	   terminating things and makes the rest of this look a bit 
	   cleaner (though it is, admittedly, a tad less efficient) */
	job->cmdBuf = command = calloc(1, 2*strlen(*commandPtr) + 1);
	job->text = NULL;

	prog = job->progs;
	prog->numRedirections = 0;
	prog->redirections = NULL;
	prog->freeGlob = 0;
	prog->isStopped = 0;

	argvAlloced = 5;
	prog->argv = xmalloc(sizeof(*prog->argv) * argvAlloced);
	prog->argv[0] = job->cmdBuf;

	buf = command;
	src = *commandPtr;
	while (*src && !done) {
		if (quote == *src) {
			quote = '\0';
		} else if (quote) {
			if (*src == '\\') {
				src++;
				if (!*src) {
					errorMsg("character expected after \\\n");
					freeJob(job);
					return 1;
				}

				/* in shell, "\'" should yield \' */
				if (*src != quote)
					*buf++ = '\\';
			} else if (*src == '*' || *src == '?' || *src == '[' ||
					   *src == ']') *buf++ = '\\';
			*buf++ = *src;
		} else if (isspace(*src)) {
			if (*prog->argv[argc]) {
				buf++, argc++;
				/* +1 here leaves room for the NULL which ends argv */
				if ((argc + 1) == argvAlloced) {
					argvAlloced += 5;
					prog->argv = realloc(prog->argv,
										 sizeof(*prog->argv) *
										 argvAlloced);
				}
				globLastArgument(prog, &argc, &argvAlloced);
				prog->argv[argc] = buf;
			}
		} else
			switch (*src) {
			case '"':
			case '\'':
				quote = *src;
				break;

			case '#':			/* comment */
				done = 1;
				break;

			case '>':			/* redirections */
			case '<':
				i = prog->numRedirections++;
				prog->redirections = realloc(prog->redirections,
											 sizeof(*prog->redirections) *
											 (i + 1));

				prog->redirections[i].fd = -1;
				if (buf != prog->argv[argc]) {
					/* the stuff before this character may be the file number 
					   being redirected */
					prog->redirections[i].fd =
						strtol(prog->argv[argc], &chptr, 10);

					if (*chptr && *prog->argv[argc]) {
						buf++, argc++;
						globLastArgument(prog, &argc, &argvAlloced);
						prog->argv[argc] = buf;
					}
				}

				if (prog->redirections[i].fd == -1) {
					if (*src == '>')
						prog->redirections[i].fd = 1;
					else
						prog->redirections[i].fd = 0;
				}

				if (*src++ == '>') {
					if (*src == '>')
						prog->redirections[i].type =
							REDIRECT_APPEND, src++;
					else
						prog->redirections[i].type = REDIRECT_OVERWRITE;
				} else {
					prog->redirections[i].type = REDIRECT_INPUT;
				}

				/* This isn't POSIX sh compliant. Oh well. */
				chptr = src;
				while (isspace(*chptr))
					chptr++;

				if (!*chptr) {
					errorMsg("file name expected after %c\n", *src);
					freeJob(job);
					job->numProgs=0;
					return 1;
				}

				prog->redirections[i].filename = buf;
				while (*chptr && !isspace(*chptr))
					*buf++ = *chptr++;

				src = chptr - 1;	/* we src++ later */
				prog->argv[argc] = ++buf;
				break;

			case '|':			/* pipe */
				/* finish this command */
				if (*prog->argv[argc])
					argc++;
				if (!argc) {
					errorMsg("empty command in pipe1\n");
					freeJob(job);
					job->numProgs=0;
					return 1;
				}
				prog->argv[argc] = NULL;

				/* and start the next */
				job->numProgs++;
				job->progs = realloc(job->progs,
									 sizeof(*job->progs) * job->numProgs);
				prog = job->progs + (job->numProgs - 1);
				prog->numRedirections = 0;
				prog->redirections = NULL;
				prog->freeGlob = 0;
				argc = 0;

				argvAlloced = 5;
				prog->argv = xmalloc(sizeof(*prog->argv) * argvAlloced);
				prog->argv[0] = ++buf;

				src++;
				while (*src && isspace(*src))
					src++;

				if (!*src) {
					errorMsg("empty command in pipe2\n");
					freeJob(job);
					job->numProgs=0;
					return 1;
				}
				src--;			/* we'll ++ it at the end of the loop */

				break;

			case '&':			/* background */
				*isBg = 1;
			case ';':			/* multiple commands */
				done = 1;
				returnCommand = *commandPtr + (src - *commandPtr) + 1;
				break;

			case '\\':
				src++;
				if (!*src) {
					errorMsg("character expected after \\\n");
					freeJob(job);
					return 1;
				}
				if (*src == '*' || *src == '[' || *src == ']'
					|| *src == '?') *buf++ = '\\';
				/* fallthrough */
			case '`':
				/* Exec a backtick-ed command */
				{
					char* newcmd=NULL;
					char* ptr=NULL;
					struct job newJob;

					ptr=strchr(++src, '`');
					if (ptr==NULL) {
						fprintf(stderr, "Unmatched '`' in command\n");
						freeJob(job);
						return 1;
					}

					newcmd = xmalloc(1+ptr-src);
					snprintf(newcmd, 1+ptr-src, src);

					if (!parseCommand(&newcmd, &newJob, jobList, isBg) &&
							newJob.numProgs) {
						runCommand(&newJob, jobList, *isBg);
					}

					/* Clip out the the backticked command from the string */
					memmove(--src, ptr, strlen(ptr)+1);
					free(newcmd);
				}
				break;
			default:
				*buf++ = *src;
			}

		src++;
	}

	if (*prog->argv[argc]) {
		argc++;
		globLastArgument(prog, &argc, &argvAlloced);
	}
	if (!argc) {
		freeJob(job);
		return 0;
	}
	prog->argv[argc] = NULL;

	if (!returnCommand) {
		job->text = xmalloc(strlen(*commandPtr) + 1);
		strcpy(job->text, *commandPtr);
	} else {
		/* This leaves any trailing spaces, which is a bit sloppy */
		count = returnCommand - *commandPtr;
		job->text = xmalloc(count + 1);
		strncpy(job->text, *commandPtr, count);
		job->text[count] = '\0';
	}

	*commandPtr = returnCommand;

	return 0;
}


static int runCommand(struct job *newJob, struct jobSet *jobList, int inBg)
{
	struct job *job;
	int i;
	int nextin, nextout;
	int pipefds[2];				/* pipefd[0] is for reading */
	struct builtInCommand *x;
#ifdef BB_FEATURE_SH_STANDALONE_SHELL
	const struct BB_applet *a = applets;
#endif


	nextin = 0, nextout = 1;
	for (i = 0; i < newJob->numProgs; i++) {
		if ((i + 1) < newJob->numProgs) {
			pipe(pipefds);
			nextout = pipefds[1];
		} else {
			nextout = 1;
		}

		/* Check if the command matches any non-forking builtins */
		for (x = bltins; x->cmd; x++) {
			if (!strcmp(newJob->progs[i].argv[0], x->cmd)) {
				return (x->function(newJob, jobList));
			}
		}

		if (!(newJob->progs[i].pid = fork())) {
			signal(SIGTTOU, SIG_DFL);

			if (nextin != 0) {
				dup2(nextin, 0);
				close(nextin);
			}

			if (nextout != 1) {
				dup2(nextout, 1);
				close(nextout);
			}

			/* explicit redirections override pipes */
			setupRedirections(newJob->progs + i);

			/* Check if the command matches any of the other builtins */
			for (x = bltins_forking; x->cmd; x++) {
				if (!strcmp(newJob->progs[i].argv[0], x->cmd)) {
					exit (x->function(newJob, jobList));
				}
			}
#ifdef BB_FEATURE_SH_STANDALONE_SHELL
			/* Check if the command matches any busybox internal commands here */
			/* TODO: Add matching when paths are appended (i.e. 'cat' currently
			 * works, but '/bin/cat' doesn't ) */
			while (a->name != 0) {
				if (strcmp(newJob->progs[i].argv[0], a->name) == 0) {
					int argc;
					char** argv=newJob->progs[i].argv;
					for(argc=0;*argv!=NULL; argv++, argc++);
					exit((*(a->main)) (argc, newJob->progs[i].argv));
				}
				a++;
			}
#endif

			execvp(newJob->progs[i].argv[0], newJob->progs[i].argv);
			fatalError("%s: %s\n", newJob->progs[i].argv[0],
					   strerror(errno));
		}

		/* put our child in the process group whose leader is the
		   first process in this pipe */
		setpgid(newJob->progs[i].pid, newJob->progs[0].pid);

		if (nextin != 0)
			close(nextin);
		if (nextout != 1)
			close(nextout);

		/* If there isn't another process, nextin is garbage 
		   but it doesn't matter */
		nextin = pipefds[0];
	}

	newJob->pgrp = newJob->progs[0].pid;

	/* find the ID for the job to use */
	newJob->jobId = 1;
	for (job = jobList->head; job; job = job->next)
		if (job->jobId >= newJob->jobId)
			newJob->jobId = job->jobId + 1;

	/* add the job to the list of running jobs */
	if (!jobList->head) {
		job = jobList->head = xmalloc(sizeof(*job));
	} else {
		for (job = jobList->head; job->next; job = job->next);
		job->next = xmalloc(sizeof(*job));
		job = job->next;
	}

	*job = *newJob;
	job->next = NULL;
	job->runningProgs = job->numProgs;
	job->stoppedProgs = 0;

	if (inBg) {
		/* we don't wait for background jobs to return -- append it 
		   to the list of backgrounded jobs and leave it alone */
		printf("[%d] %d\n", job->jobId,
			   newJob->progs[newJob->numProgs - 1].pid);
	} else {
		jobList->fg = job;

		/* move the new process group into the foreground */
		/* suppress messages when run from /linuxrc mag@sysgo.de */
		if (tcsetpgrp(0, newJob->pgrp) && errno != ENOTTY)
			perror("tcsetpgrp");
	}

	return 0;
}

static int setupRedirections(struct childProgram *prog)
{
	int i;
	int openfd;
	int mode = O_RDONLY;
	struct redirectionSpecifier *redir = prog->redirections;

	for (i = 0; i < prog->numRedirections; i++, redir++) {
		switch (redir->type) {
		case REDIRECT_INPUT:
			mode = O_RDONLY;
			break;
		case REDIRECT_OVERWRITE:
			mode = O_RDWR | O_CREAT | O_TRUNC;
			break;
		case REDIRECT_APPEND:
			mode = O_RDWR | O_CREAT | O_APPEND;
			break;
		}

		openfd = open(redir->filename, mode, 0666);
		if (openfd < 0) {
			/* this could get lost if stderr has been redirected, but
			   bash and ash both lose it as well (though zsh doesn't!) */
			errorMsg("error opening %s: %s\n", redir->filename,
					strerror(errno));
			return 1;
		}

		if (openfd != redir->fd) {
			dup2(openfd, redir->fd);
			close(openfd);
		}
	}

	return 0;
}


static int busy_loop(FILE * input)
{
	char *command;
	char *nextCommand = NULL;
	struct jobSet jobList = { NULL, NULL };
	struct job newJob;
	pid_t  parent_pgrp;
	int i;
	int status;
	int inBg;

	/* save current owner of TTY so we can restore it on exit */
	parent_pgrp = tcgetpgrp(0);

	command = (char *) calloc(BUFSIZ, sizeof(char));

	/* don't pay any attention to this signal; it just confuses 
	   things and isn't really meant for shells anyway */
	signal(SIGTTOU, SIG_IGN);

	while (1) {
		if (!jobList.fg) {
			/* no job is in the foreground */

			/* see if any background processes have exited */
			checkJobs(&jobList);

			if (!nextCommand) {
				if (getCommand(input, command))
					break;
				nextCommand = command;
			}

			if (!parseCommand(&nextCommand, &newJob, &jobList, &inBg) &&
				newJob.numProgs) {
				runCommand(&newJob, &jobList, inBg);
			} else {
				nextCommand=NULL;
			}
		} else {
			/* a job is running in the foreground; wait for it */
			i = 0;
			while (!jobList.fg->progs[i].pid ||
				   jobList.fg->progs[i].isStopped) i++;

			waitpid(jobList.fg->progs[i].pid, &status, WUNTRACED);

			if (WIFEXITED(status) || WIFSIGNALED(status)) {
				/* the child exited */
				jobList.fg->runningProgs--;
				jobList.fg->progs[i].pid = 0;

				if (!jobList.fg->runningProgs) {
					/* child exited */

					removeJob(&jobList, jobList.fg);
					jobList.fg = NULL;
				}
			} else {
				/* the child was stopped */
				jobList.fg->stoppedProgs++;
				jobList.fg->progs[i].isStopped = 1;

				if (jobList.fg->stoppedProgs == jobList.fg->runningProgs) {
					printf("\n" JOB_STATUS_FORMAT, jobList.fg->jobId,
						   "Stopped", jobList.fg->text);
					jobList.fg = NULL;
				}
			}

			if (!jobList.fg) {
				/* move the shell to the foreground */
				/* suppress messages when run from /linuxrc mag@sysgo.de */
				if (tcsetpgrp(0, getpid()) && errno != ENOTTY)
					perror("tcsetpgrp"); 
			}
		}
	}
	free(command);

	/* return controlling TTY back to parent process group before exiting */
	if (tcsetpgrp(0, parent_pgrp))
		perror("tcsetpgrp");

	/* return exit status if called with "-c" */
	if (input == NULL && WIFEXITED(status))
		return WEXITSTATUS(status);
	
	return 0;
}


int shell_main(int argc, char **argv)
{
	FILE *input = stdin;

	/* initialize the cwd */
	cwd = (char *) calloc(BUFSIZ, sizeof(char));
	if (cwd == 0) {
		fatalError("out of memory\n");
	}
	getcwd(cwd, sizeof(char)*BUFSIZ);

#ifdef BB_FEATURE_SH_COMMAND_EDITING
	cmdedit_init();
	signal(SIGWINCH, win_changed);
	win_changed(0);
#endif

	//if (argv[0] && argv[0][0] == '-') {
	//      builtin_source("/etc/profile");
	//}

	if (argc < 2) {
		fprintf(stdout, "\n\nBusyBox v%s (%s) Built-in shell\n", BB_VER, BB_BT);
		fprintf(stdout, "Enter 'help' for a list of built-in commands.\n\n");
	} else {
		if (argv[1][0]=='-' && argv[1][1]=='c') {
			int i;
			local_pending_command = (char *) calloc(BUFSIZ, sizeof(char));
			if (local_pending_command == 0) {
				fatalError("out of memory\n");
			}
			for(i=2; i<argc; i++)
			{
				if (strlen(local_pending_command) + strlen(argv[i]) >= BUFSIZ) {
					local_pending_command = realloc(local_pending_command, 
							strlen(local_pending_command) + strlen(argv[i]));
					if (local_pending_command==NULL) 
					  fatalError("commands for -c option too long\n");
				}
				strcat(local_pending_command, argv[i]);
				if ( (i + 1) < argc)
				  strcat(local_pending_command, " ");
			}
			input = NULL;
			  
		}
		else if (argv[1][0]=='-') {
			usage(shell_usage);
		}
		else {
			input = fopen(argv[1], "r");
			if (!input) {
				fatalError("Couldn't open file '%s': %s\n", argv[1],
						   strerror(errno));
			}
		}
	}

	return (busy_loop(input));
}