summaryrefslogtreecommitdiff
path: root/shell/shell_common.c
blob: 9345005c7fa91e69fd60950c4347224f4de4aa1a (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
/* vi: set sw=4 ts=4: */
/*
 * Adapted from ash applet code
 *
 * This code is derived from software contributed to Berkeley by
 * Kenneth Almquist.
 *
 * Copyright (c) 1989, 1991, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * Copyright (c) 1997-2005 Herbert Xu <herbert@gondor.apana.org.au>
 * was re-ported from NetBSD and debianized.
 *
 * Copyright (c) 2010 Denys Vlasenko
 * Split from ash.c
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
#include "libbb.h"
#include "shell_common.h"

const char defifsvar[] ALIGN1 = "IFS= \t\n";


int FAST_FUNC is_well_formed_var_name(const char *s, char terminator)
{
	if (!s || !(isalpha(*s) || *s == '_'))
		return 0;

	do
		s++;
	while (isalnum(*s) || *s == '_');

	return *s == terminator;
}

/* read builtin */

//TODO: use more efficient setvar() which takes a pointer to malloced "VAR=VAL"
//string. hush naturally has it, and ash has setvareq().
//Here we can simply store "VAR=" at buffer start and store read data directly
//after "=", then pass buffer to setvar() to consume.
const char* FAST_FUNC
shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
	char       **argv,
	const char *ifs,
	int        read_flags,
	const char *opt_n,
	const char *opt_p,
	const char *opt_t,
	const char *opt_u
)
{
	unsigned end_ms; /* -t TIMEOUT */
	int fd; /* -u FD */
	int nchars; /* -n NUM */
	char **pp;
	char *buffer;
	struct termios tty, old_tty;
	const char *retval;
	int bufpos; /* need to be able to hold -1 */
	int startword;
	smallint backslash;

	pp = argv;
	while (*pp) {
		if (!is_well_formed_var_name(*pp, '\0')) {
			/* Mimic bash message */
			bb_error_msg("read: '%s': not a valid identifier", *pp);
			return (const char *)(uintptr_t)1;
		}
		pp++;
	}

	nchars = 0; /* if != 0, -n is in effect */
	if (opt_n) {
		nchars = bb_strtou(opt_n, NULL, 10);
		if (nchars < 0 || errno)
			return "invalid count";
		/* note: "-n 0": off (bash 3.2 does this too) */
	}
	end_ms = 0;
	if (opt_t) {
		end_ms = bb_strtou(opt_t, NULL, 10);
		if (errno || end_ms > UINT_MAX / 2048)
			return "invalid timeout";
		end_ms *= 1000;
#if 0 /* even bash has no -t N.NNN support */
		ts.tv_sec = bb_strtou(opt_t, &p, 10);
		ts.tv_usec = 0;
		/* EINVAL means number is ok, but not terminated by NUL */
		if (*p == '.' && errno == EINVAL) {
			char *p2;
			if (*++p) {
				int scale;
				ts.tv_usec = bb_strtou(p, &p2, 10);
				if (errno)
					return "invalid timeout";
				scale = p2 - p;
				/* normalize to usec */
				if (scale > 6)
					return "invalid timeout";
				while (scale++ < 6)
					ts.tv_usec *= 10;
			}
		} else if (ts.tv_sec < 0 || errno) {
			return "invalid timeout";
		}
		if (!(ts.tv_sec | ts.tv_usec)) { /* both are 0? */
			return "invalid timeout";
		}
#endif /* if 0 */
	}
	fd = STDIN_FILENO;
	if (opt_u) {
		fd = bb_strtou(opt_u, NULL, 10);
		if (fd < 0 || errno)
			return "invalid file descriptor";
	}

	if (opt_p && isatty(fd)) {
		fputs(opt_p, stderr);
		fflush_all();
	}

	if (ifs == NULL)
		ifs = defifs;

	if (nchars || (read_flags & BUILTIN_READ_SILENT)) {
		tcgetattr(fd, &tty);
		old_tty = tty;
		if (nchars) {
			tty.c_lflag &= ~ICANON;
			tty.c_cc[VMIN] = nchars < 256 ? nchars : 255;
		}
		if (read_flags & BUILTIN_READ_SILENT) {
			tty.c_lflag &= ~(ECHO | ECHOK | ECHONL);
		}
		/* This forces execution of "restoring" tcgetattr later */
		read_flags |= BUILTIN_READ_SILENT;
		/* if tcgetattr failed, tcsetattr will fail too.
		 * Ignoring, it's harmless. */
		tcsetattr(fd, TCSANOW, &tty);
	}

	retval = (const char *)(uintptr_t)0;
	startword = 1;
	backslash = 0;
	if (end_ms) /* NB: end_ms stays nonzero: */
		end_ms = ((unsigned)monotonic_ms() + end_ms) | 1;
	buffer = NULL;
	bufpos = 0;
	do {
		char c;

		if (end_ms) {
			int timeout;
			struct pollfd pfd[1];

			pfd[0].fd = fd;
			pfd[0].events = POLLIN;
			timeout = end_ms - (unsigned)monotonic_ms();
			if (timeout <= 0 /* already late? */
			 || safe_poll(pfd, 1, timeout) != 1 /* no? wait... */
			) { /* timed out! */
				retval = (const char *)(uintptr_t)1;
				goto ret;
			}
		}

		if ((bufpos & 0xff) == 0)
			buffer = xrealloc(buffer, bufpos + 0x100);
		if (nonblock_safe_read(fd, &buffer[bufpos], 1) != 1) {
			retval = (const char *)(uintptr_t)1;
			break;
		}
		c = buffer[bufpos];
		if (c == '\0')
			continue;
		if (backslash) {
			backslash = 0;
			if (c != '\n')
				goto put;
			continue;
		}
		if (!(read_flags & BUILTIN_READ_RAW) && c == '\\') {
			backslash = 1;
			continue;
		}
		if (c == '\n')
			break;

		/* $IFS splitting. NOT done if we run "read"
		 * without variable names (bash compat).
		 * Thus, "read" and "read REPLY" are not the same.
		 */
		if (argv[0]) {
/* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_05 */
			const char *is_ifs = strchr(ifs, c);
			if (startword && is_ifs) {
				if (isspace(c))
					continue;
				/* it is a non-space ifs char */
				startword--;
				if (startword == 1) /* first one? */
					continue; /* yes, it is not next word yet */
			}
			startword = 0;
			if (argv[1] != NULL && is_ifs) {
				buffer[bufpos] = '\0';
				bufpos = 0;
				setvar(*argv, buffer);
				argv++;
				/* can we skip one non-space ifs char? (2: yes) */
				startword = isspace(c) ? 2 : 1;
				continue;
			}
		}
 put:
		bufpos++;
	} while (--nchars);

	if (argv[0]) {
		/* Remove trailing space $IFS chars */
		while (--bufpos >= 0 && isspace(buffer[bufpos]) && strchr(ifs, buffer[bufpos]) != NULL)
			continue;
		buffer[bufpos + 1] = '\0';
		/* Use the remainder as a value for the next variable */
		setvar(*argv, buffer);
		/* Set the rest to "" */
		while (*++argv)
			setvar(*argv, "");
	} else {
		/* Note: no $IFS removal */
		buffer[bufpos] = '\0';
		setvar("REPLY", buffer);
	}

 ret:
	free(buffer);
	if (read_flags & BUILTIN_READ_SILENT)
		tcsetattr(fd, TCSANOW, &old_tty);
	return retval;
}

/* ulimit builtin */

struct limits {
	uint8_t cmd;            /* RLIMIT_xxx fit into it */
	uint8_t factor_shift;   /* shift by to get rlim_{cur,max} values */
	char option;
	const char *name;
};

static const struct limits limits_tbl[] = {
#ifdef RLIMIT_FSIZE
	{ RLIMIT_FSIZE,		9,	'f',	"file size (blocks)" },
#endif
#ifdef RLIMIT_CPU
	{ RLIMIT_CPU,		0,	't',	"cpu time (seconds)" },
#endif
#ifdef RLIMIT_DATA
	{ RLIMIT_DATA,		10,	'd',	"data seg size (kb)" },
#endif
#ifdef RLIMIT_STACK
	{ RLIMIT_STACK,		10,	's',	"stack size (kb)" },
#endif
#ifdef RLIMIT_CORE
	{ RLIMIT_CORE,		9,	'c',	"core file size (blocks)" },
#endif
#ifdef RLIMIT_RSS
	{ RLIMIT_RSS,		10,	'm',	"resident set size (kb)" },
#endif
#ifdef RLIMIT_MEMLOCK
	{ RLIMIT_MEMLOCK,	10,	'l',	"locked memory (kb)" },
#endif
#ifdef RLIMIT_NPROC
	{ RLIMIT_NPROC,		0,	'p',	"processes" },
#endif
#ifdef RLIMIT_NOFILE
	{ RLIMIT_NOFILE,	0,	'n',	"file descriptors" },
#endif
#ifdef RLIMIT_AS
	{ RLIMIT_AS,		10,	'v',	"address space (kb)" },
#endif
#ifdef RLIMIT_LOCKS
	{ RLIMIT_LOCKS,		0,	'w',	"locks" },
#endif
};

enum {
	OPT_hard = (1 << 0),
	OPT_soft = (1 << 1),
};

/* "-": treat args as parameters of option with ASCII code 1 */
static const char ulimit_opt_string[] = "-HSa"
#ifdef RLIMIT_FSIZE
			"f::"
#endif
#ifdef RLIMIT_CPU
			"t::"
#endif
#ifdef RLIMIT_DATA
			"d::"
#endif
#ifdef RLIMIT_STACK
			"s::"
#endif
#ifdef RLIMIT_CORE
			"c::"
#endif
#ifdef RLIMIT_RSS
			"m::"
#endif
#ifdef RLIMIT_MEMLOCK
			"l::"
#endif
#ifdef RLIMIT_NPROC
			"p::"
#endif
#ifdef RLIMIT_NOFILE
			"n::"
#endif
#ifdef RLIMIT_AS
			"v::"
#endif
#ifdef RLIMIT_LOCKS
			"w::"
#endif
			;

static void printlim(unsigned opts, const struct rlimit *limit,
			const struct limits *l)
{
	rlim_t val;

	val = limit->rlim_max;
	if (!(opts & OPT_hard))
		val = limit->rlim_cur;

	if (val == RLIM_INFINITY)
		printf("unlimited\n");
	else {
		val >>= l->factor_shift;
		printf("%llu\n", (long long) val);
	}
}

int FAST_FUNC
shell_builtin_ulimit(char **argv)
{
	unsigned opts;
	unsigned argc;

	/* We can't use getopt32: need to handle commands like
	 * ulimit 123 -c2 -l 456
	 */

	/* In case getopt was already called:
	 * reset the libc getopt() function, which keeps internal state.
	 */
#ifdef __GLIBC__
	optind = 0;
#else /* BSD style */
	optind = 1;
	/* optreset = 1; */
#endif
	/* optarg = NULL; opterr = 0; optopt = 0; - do we need this?? */

        argc = 1;
        while (argv[argc])
                argc++;

	opts = 0;
	while (1) {
		struct rlimit limit;
		const struct limits *l;
		int opt_char = getopt(argc, argv, ulimit_opt_string);

		if (opt_char == -1)
			break;
		if (opt_char == 'H') {
			opts |= OPT_hard;
			continue;
		}
		if (opt_char == 'S') {
			opts |= OPT_soft;
			continue;
		}

		if (opt_char == 'a') {
			for (l = limits_tbl; l != &limits_tbl[ARRAY_SIZE(limits_tbl)]; l++) {
				getrlimit(l->cmd, &limit);
				printf("-%c: %-30s ", l->option, l->name);
				printlim(opts, &limit, l);
			}
			continue;
		}

		if (opt_char == 1)
			opt_char = 'f';
		for (l = limits_tbl; l != &limits_tbl[ARRAY_SIZE(limits_tbl)]; l++) {
			if (opt_char == l->option) {
				char *val_str;

				getrlimit(l->cmd, &limit);

				val_str = optarg;
				if (!val_str && argv[optind] && argv[optind][0] != '-')
					val_str = argv[optind++]; /* ++ skips NN in "-c NN" case */
				if (val_str) {
					rlim_t val;

					if (strcmp(val_str, "unlimited") == 0)
						val = RLIM_INFINITY;
					else {
						if (sizeof(val) == sizeof(int))
							val = bb_strtou(val_str, NULL, 10);
						else if (sizeof(val) == sizeof(long))
							val = bb_strtoul(val_str, NULL, 10);
						else
							val = bb_strtoull(val_str, NULL, 10);
						if (errno) {
							bb_error_msg("bad number");
							return EXIT_FAILURE;
						}
						val <<= l->factor_shift;
					}
//bb_error_msg("opt %c val_str:'%s' val:%lld", opt_char, val_str, (long long)val);
					/* from man bash: "If neither -H nor -S
					 * is specified, both the soft and hard
					 * limits are set. */
					if (!opts)
						opts = OPT_hard + OPT_soft;
					if (opts & OPT_hard)
						limit.rlim_max = val;
					if (opts & OPT_soft)
						limit.rlim_cur = val;
//bb_error_msg("setrlimit(%d, %lld, %lld)", l->cmd, (long long)limit.rlim_cur, (long long)limit.rlim_max);
					if (setrlimit(l->cmd, &limit) < 0) {
						bb_perror_msg("error setting limit");
						return EXIT_FAILURE;
					}
				} else {
					printlim(opts, &limit, l);
				}
				break;
			}
		} /* for (every possible opt) */

		if (l == &limits_tbl[ARRAY_SIZE(limits_tbl)]) {
			/* bad option. getopt already complained. */
			break;
		}

	} /* while (there are options) */

	return 0;
}