1 /* vi: set sw=4 ts=4: */
2 /*
3 * Adapted from ash applet code
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Kenneth Almquist.
7 *
8 * Copyright (c) 1989, 1991, 1993, 1994
9 * The Regents of the University of California. All rights reserved.
10 *
11 * Copyright (c) 1997-2005 Herbert Xu <herbert@gondor.apana.org.au>
12 * was re-ported from NetBSD and debianized.
13 *
14 * Copyright (c) 2010 Denys Vlasenko
15 * Split from ash.c
16 *
17 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
18 */
19 #include "libbb.h"
20 #include "shell_common.h"
21
22 const char defifsvar[] ALIGN1 = "IFS= \t\n";
23 const char defoptindvar[] ALIGN1 = "OPTIND=1";
24
25 /* read builtin */
26
27 /* Needs to be interruptible: shell must handle traps and shell-special signals
28 * while inside read. To implement this, be sure to not loop on EINTR
29 * and return errno == EINTR reliably.
30 */
31 //TODO: use more efficient setvar() which takes a pointer to malloced "VAR=VAL"
32 //string. hush naturally has it, and ash has setvareq().
33 //Here we can simply store "VAR=" at buffer start and store read data directly
34 //after "=", then pass buffer to setvar() to consume.
35 const char* FAST_FUNC
shell_builtin_read(struct builtin_read_params * params)36 shell_builtin_read(struct builtin_read_params *params)
37 {
38 struct pollfd pfd[1];
39 #define fd (pfd[0].fd) /* -u FD */
40 unsigned err;
41 unsigned end_ms; /* -t TIMEOUT */
42 int nchars; /* -n NUM */
43 char **pp;
44 char *buffer;
45 char delim;
46 struct termios tty, old_tty;
47 const char *retval;
48 int bufpos; /* need to be able to hold -1 */
49 int startword;
50 smallint backslash;
51 char **argv;
52 const char *ifs;
53 int read_flags;
54
55 errno = err = 0;
56
57 argv = params->argv;
58 pp = argv;
59 while (*pp) {
60 if (endofname(*pp)[0] != '\0') {
61 /* Mimic bash message */
62 bb_error_msg("read: '%s': bad variable name", *pp);
63 return (const char *)(uintptr_t)1;
64 }
65 pp++;
66 }
67
68 nchars = 0; /* if != 0, -n is in effect */
69 if (params->opt_n) {
70 nchars = bb_strtou(params->opt_n, NULL, 10);
71 if (nchars < 0 || errno)
72 return "invalid count";
73 /* note: "-n 0": off (bash 3.2 does this too) */
74 }
75
76 end_ms = 0;
77 if (params->opt_t && !ENABLE_FEATURE_SH_READ_FRAC) {
78 end_ms = bb_strtou(params->opt_t, NULL, 10);
79 if (errno)
80 return "invalid timeout";
81 if (end_ms > UINT_MAX / 2048) /* be safely away from overflow */
82 end_ms = UINT_MAX / 2048;
83 end_ms *= 1000;
84 }
85 if (params->opt_t && ENABLE_FEATURE_SH_READ_FRAC) {
86 /* bash 4.3 (maybe earlier) supports -t N.NNNNNN */
87 char *p;
88 /* Eat up to three fractional digits */
89 int frac_digits = 3 + 1;
90
91 end_ms = bb_strtou(params->opt_t, &p, 10);
92 if (end_ms > UINT_MAX / 2048) /* be safely away from overflow */
93 end_ms = UINT_MAX / 2048;
94
95 if (errno) {
96 /* EINVAL = number is ok, but not NUL terminated */
97 if (errno != EINVAL || *p != '.')
98 return "invalid timeout";
99 /* Do not check the rest: bash allows "0.123456xyz" */
100 while (*++p && --frac_digits) {
101 end_ms *= 10;
102 end_ms += (*p - '0');
103 if ((unsigned char)(*p - '0') > 9)
104 return "invalid timeout";
105 }
106 }
107 while (--frac_digits > 0) {
108 end_ms *= 10;
109 }
110 }
111
112 fd = STDIN_FILENO;
113 if (params->opt_u) {
114 fd = bb_strtou(params->opt_u, NULL, 10);
115 if (fd < 0 || errno)
116 return "invalid file descriptor";
117 }
118
119 if (params->opt_t && end_ms == 0) {
120 /* "If timeout is 0, read returns immediately, without trying
121 * to read any data. The exit status is 0 if input is available
122 * on the specified file descriptor, non-zero otherwise."
123 * bash seems to ignore -p PROMPT for this use case.
124 */
125 int r;
126 pfd[0].events = POLLIN;
127 r = poll(pfd, 1, /*timeout:*/ 0);
128 /* Return 0 only if poll returns 1 ("one fd ready"), else return 1: */
129 return (const char *)(uintptr_t)(r <= 0);
130 }
131
132 if (params->opt_p && isatty(fd)) {
133 fputs(params->opt_p, stderr);
134 fflush_all();
135 }
136
137 ifs = params->ifs;
138 if (ifs == NULL)
139 ifs = defifs;
140
141 read_flags = params->read_flags;
142 if (nchars || (read_flags & BUILTIN_READ_SILENT)) {
143 tcgetattr(fd, &tty);
144 old_tty = tty;
145 if (nchars) {
146 tty.c_lflag &= ~ICANON;
147 // Setting it to more than 1 breaks poll():
148 // it blocks even if there's data. !??
149 //tty.c_cc[VMIN] = nchars < 256 ? nchars : 255;
150 /* reads will block only if < 1 char is available */
151 tty.c_cc[VMIN] = 1;
152 /* no timeout (reads block forever) */
153 tty.c_cc[VTIME] = 0;
154 }
155 if (read_flags & BUILTIN_READ_SILENT) {
156 tty.c_lflag &= ~(ECHO | ECHOK | ECHONL);
157 }
158 /* This forces execution of "restoring" tcgetattr later */
159 read_flags |= BUILTIN_READ_SILENT;
160 /* if tcgetattr failed, tcsetattr will fail too.
161 * Ignoring, it's harmless. */
162 tcsetattr(fd, TCSANOW, &tty);
163 }
164
165 retval = (const char *)(uintptr_t)0;
166 startword = 1;
167 backslash = 0;
168 if (params->opt_t)
169 end_ms += (unsigned)monotonic_ms();
170 buffer = NULL;
171 bufpos = 0;
172 delim = params->opt_d ? params->opt_d[0] : '\n';
173 do {
174 char c;
175 int timeout;
176
177 if ((bufpos & 0xff) == 0)
178 buffer = xrealloc(buffer, bufpos + 0x101);
179
180 timeout = -1;
181 if (params->opt_t) {
182 timeout = end_ms - (unsigned)monotonic_ms();
183 /* ^^^^^^^^^^^^^ all values are unsigned,
184 * wrapping math is used here, good even if
185 * 32-bit unix time wrapped (year 2038+).
186 */
187 if (timeout <= 0) { /* already late? */
188 retval = (const char *)(uintptr_t)1;
189 goto ret;
190 }
191 }
192
193 /* We must poll even if timeout is -1:
194 * we want to be interrupted if signal arrives,
195 * regardless of SA_RESTART-ness of that signal!
196 */
197 errno = 0;
198 pfd[0].events = POLLIN;
199 if (poll(pfd, 1, timeout) <= 0) {
200 /* timed out, or EINTR */
201 err = errno;
202 retval = (const char *)(uintptr_t)1;
203 goto ret;
204 }
205 if (read(fd, &buffer[bufpos], 1) != 1) {
206 err = errno;
207 retval = (const char *)(uintptr_t)1;
208 break;
209 }
210
211 c = buffer[bufpos];
212 if (!(read_flags & BUILTIN_READ_RAW)) {
213 if (backslash) {
214 backslash = 0;
215 if (c != '\n')
216 goto put;
217 continue;
218 }
219 if (c == '\\') {
220 backslash = 1;
221 continue;
222 }
223 }
224 if (c == delim) /* '\n' or -d CHAR */
225 break;
226 if (c == '\0')
227 continue;
228
229 /* $IFS splitting. NOT done if we run "read"
230 * without variable names (bash compat).
231 * Thus, "read" and "read REPLY" are not the same.
232 */
233 if (argv[0]) {
234 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_05 */
235 const char *is_ifs = strchr(ifs, c);
236 if (startword && is_ifs) {
237 if (isspace(c))
238 continue;
239 /* it is a non-space ifs char */
240 startword--;
241 if (startword == 1) /* first one? */
242 continue; /* yes, it is not next word yet */
243 }
244 startword = 0;
245 if (argv[1] != NULL && is_ifs) {
246 buffer[bufpos] = '\0';
247 bufpos = 0;
248 params->setvar(*argv, buffer);
249 argv++;
250 /* can we skip one non-space ifs char? (2: yes) */
251 startword = isspace(c) ? 2 : 1;
252 continue;
253 }
254 }
255 put:
256 bufpos++;
257 } while (--nchars);
258
259 if (argv[0]) {
260 /* Remove trailing space $IFS chars */
261 while (--bufpos >= 0
262 && isspace(buffer[bufpos])
263 && strchr(ifs, buffer[bufpos]) != NULL
264 ) {
265 continue;
266 }
267 buffer[bufpos + 1] = '\0';
268
269 /* Last variable takes the entire remainder with delimiters
270 * (sans trailing whitespace $IFS),
271 * but ***only "if there are fewer vars than fields"(c)***!
272 * The "X:Y:" case below: there are two fields,
273 * and therefore last delimiter (:) is eaten:
274 * IFS=": "
275 * echo "X:Y:Z:" | (read x y; echo "|$x|$y|") # |X|Y:Z:|
276 * echo "X:Y:Z" | (read x y; echo "|$x|$y|") # |X|Y:Z|
277 * echo "X:Y:" | (read x y; echo "|$x|$y|") # |X|Y|, not |X|Y:|
278 * echo "X:Y : " | (read x y; echo "|$x|$y|") # |X|Y|
279 */
280 if (bufpos >= 0
281 && strchr(ifs, buffer[bufpos]) != NULL
282 ) {
283 /* There _is_ a non-whitespace IFS char */
284 /* Skip whitespace IFS char before it */
285 while (--bufpos >= 0
286 && isspace(buffer[bufpos])
287 && strchr(ifs, buffer[bufpos]) != NULL
288 ) {
289 continue;
290 }
291 /* Are there $IFS chars? */
292 if (strcspn(buffer, ifs) >= ++bufpos) {
293 /* No: last var takes one field, not more */
294 /* So, drop trailing IFS delims */
295 buffer[bufpos] = '\0';
296 }
297 }
298
299 /* Use the remainder as a value for the next variable */
300 params->setvar(*argv, buffer);
301 /* Set the rest to "" */
302 while (*++argv)
303 params->setvar(*argv, "");
304 } else {
305 /* Note: no $IFS removal */
306 buffer[bufpos] = '\0';
307 params->setvar("REPLY", buffer);
308 }
309
310 ret:
311 free(buffer);
312 if (read_flags & BUILTIN_READ_SILENT)
313 tcsetattr(fd, TCSANOW, &old_tty);
314
315 errno = err;
316 return retval;
317 #undef fd
318 }
319
320 /* ulimit builtin */
321
322 struct limits {
323 uint8_t cmd; /* RLIMIT_xxx fit into it */
324 uint8_t factor_shift; /* shift by to get rlim_{cur,max} values */
325 };
326
327 /* Order of entries matches order in which bash prints "ulimit -a" */
328 static const struct limits limits_tbl[] ALIGN2 = {
329 { RLIMIT_CORE, 9, }, // -c
330 { RLIMIT_DATA, 10, }, // -d
331 #ifdef RLIMIT_NICE
332 { RLIMIT_NICE, 0, }, // -e
333 #define LIMIT_F_IDX 3
334 #else
335 /* for example, Hurd */
336 #define LIMIT_F_IDX 2
337 #endif
338 { RLIMIT_FSIZE, 9, }, // -f
339 #ifdef RLIMIT_SIGPENDING
340 { RLIMIT_SIGPENDING, 0, }, // -i
341 #endif
342 #ifdef RLIMIT_MEMLOCK
343 { RLIMIT_MEMLOCK, 10, }, // -l
344 #endif
345 #ifdef RLIMIT_RSS
346 { RLIMIT_RSS, 10, }, // -m
347 #endif
348 #ifdef RLIMIT_NOFILE
349 { RLIMIT_NOFILE, 0, }, // -n
350 #endif
351 #ifdef RLIMIT_MSGQUEUE
352 { RLIMIT_MSGQUEUE, 0, }, // -q
353 #endif
354 #ifdef RLIMIT_RTPRIO
355 { RLIMIT_RTPRIO, 0, }, // -r
356 #endif
357 #ifdef RLIMIT_STACK
358 { RLIMIT_STACK, 10, }, // -s
359 #endif
360 #ifdef RLIMIT_CPU
361 { RLIMIT_CPU, 0, }, // -t
362 #endif
363 #ifdef RLIMIT_NPROC
364 { RLIMIT_NPROC, 0, }, // -u
365 #endif
366 #ifdef RLIMIT_AS
367 { RLIMIT_AS, 10, }, // -v
368 #endif
369 #ifdef RLIMIT_LOCKS
370 { RLIMIT_LOCKS, 0, }, // -x
371 #endif
372 };
373 // 1) bash also shows:
374 //pipe size (512 bytes, -p) 8
375 // 2) RLIMIT_RTTIME ("timeout for RT tasks in us") is not in the table
376
377 static const char limits_help[] ALIGN1 =
378 "core file size (blocks)" // -c
379 "\0""data seg size (kb)" // -d
380 #ifdef RLIMIT_NICE
381 "\0""scheduling priority" // -e
382 #endif
383 "\0""file size (blocks)" // -f
384 #ifdef RLIMIT_SIGPENDING
385 "\0""pending signals" // -i
386 #endif
387 #ifdef RLIMIT_MEMLOCK
388 "\0""max locked memory (kb)" // -l
389 #endif
390 #ifdef RLIMIT_RSS
391 "\0""max memory size (kb)" // -m
392 #endif
393 #ifdef RLIMIT_NOFILE
394 "\0""open files" // -n
395 #endif
396 #ifdef RLIMIT_MSGQUEUE
397 "\0""POSIX message queues (bytes)" // -q
398 #endif
399 #ifdef RLIMIT_RTPRIO
400 "\0""real-time priority" // -r
401 #endif
402 #ifdef RLIMIT_STACK
403 "\0""stack size (kb)" // -s
404 #endif
405 #ifdef RLIMIT_CPU
406 "\0""cpu time (seconds)" // -t
407 #endif
408 #ifdef RLIMIT_NPROC
409 "\0""max user processes" // -u
410 #endif
411 #ifdef RLIMIT_AS
412 "\0""virtual memory (kb)" // -v
413 #endif
414 #ifdef RLIMIT_LOCKS
415 "\0""file locks" // -x
416 #endif
417 ;
418
419 static const char limit_chars[] ALIGN1 =
420 "c"
421 "d"
422 #ifdef RLIMIT_NICE
423 "e"
424 #endif
425 "f"
426 #ifdef RLIMIT_SIGPENDING
427 "i"
428 #endif
429 #ifdef RLIMIT_MEMLOCK
430 "l"
431 #endif
432 #ifdef RLIMIT_RSS
433 "m"
434 #endif
435 #ifdef RLIMIT_NOFILE
436 "n"
437 #endif
438 #ifdef RLIMIT_MSGQUEUE
439 "q"
440 #endif
441 #ifdef RLIMIT_RTPRIO
442 "r"
443 #endif
444 #ifdef RLIMIT_STACK
445 "s"
446 #endif
447 #ifdef RLIMIT_CPU
448 "t"
449 #endif
450 #ifdef RLIMIT_NPROC
451 "u"
452 #endif
453 #ifdef RLIMIT_AS
454 "v"
455 #endif
456 #ifdef RLIMIT_LOCKS
457 "x"
458 #endif
459 ;
460
461 /* "-": treat args as parameters of option with ASCII code 1 */
462 static const char ulimit_opt_string[] ALIGN1 = "-HSa"
463 "c::"
464 "d::"
465 #ifdef RLIMIT_NICE
466 "e::"
467 #endif
468 "f::"
469 #ifdef RLIMIT_SIGPENDING
470 "i::"
471 #endif
472 #ifdef RLIMIT_MEMLOCK
473 "l::"
474 #endif
475 #ifdef RLIMIT_RSS
476 "m::"
477 #endif
478 #ifdef RLIMIT_NOFILE
479 "n::"
480 #endif
481 #ifdef RLIMIT_MSGQUEUE
482 "q::"
483 #endif
484 #ifdef RLIMIT_RTPRIO
485 "r::"
486 #endif
487 #ifdef RLIMIT_STACK
488 "s::"
489 #endif
490 #ifdef RLIMIT_CPU
491 "t::"
492 #endif
493 #ifdef RLIMIT_NPROC
494 "u::"
495 #endif
496 #ifdef RLIMIT_AS
497 "v::"
498 #endif
499 #ifdef RLIMIT_LOCKS
500 "x::"
501 #endif
502 ;
503
504 enum {
505 OPT_hard = (1 << 0),
506 OPT_soft = (1 << 1),
507 OPT_all = (1 << 2),
508 };
509
printlim(unsigned opts,const struct rlimit * limit,const struct limits * l)510 static void printlim(unsigned opts, const struct rlimit *limit,
511 const struct limits *l)
512 {
513 rlim_t val;
514
515 val = limit->rlim_max;
516 if (opts & OPT_soft)
517 val = limit->rlim_cur;
518
519 if (val == RLIM_INFINITY)
520 puts("unlimited");
521 else {
522 val >>= l->factor_shift;
523 printf("%llu\n", (long long) val);
524 }
525 }
526
527 int FAST_FUNC
shell_builtin_ulimit(char ** argv)528 shell_builtin_ulimit(char **argv)
529 {
530 struct rlimit limit;
531 unsigned opt_cnt;
532 unsigned opts;
533 unsigned argc;
534 unsigned i;
535
536 /* We can't use getopt32: need to handle commands like
537 * ulimit 123 -c2 -l 456
538 */
539
540 /* In case getopt() was already called:
541 * reset libc getopt() internal state.
542 */
543 GETOPT_RESET();
544
545 // bash 4.4.23:
546 //
547 // -H and/or -S change meaning even of options *before* them: ulimit -f 2000 -H
548 // sets hard limit, ulimit -a -H prints hard limits.
549 //
550 // -a is equivalent for requesting all limits to be shown.
551 //
552 // If -a is specified, attempts to set limits are ignored:
553 // ulimit -m 1000; ulimit -m 2000 -a
554 // shows 1000, not 2000. HOWEVER, *implicit* -f form "ulimit 2000 -a"
555 // DOES set -f limit [we don't implement this quirk], "ulimit -a 2000" does not.
556 // Options are still parsed: ulimit -az complains about unknown -z opt.
557 //
558 // -a is not cumulative: "ulimit -a -a" = "ulimit -a -f -m" = "ulimit -a"
559 //
560 // -HSa can be combined in one argument and with one other option (example: -Sm),
561 // but other options can't: limit value is an optional argument,
562 // thus "-mf" means "-m f", f is the parameter of -m.
563 //
564 // Limit can be set and then printed: ulimit -m 2000 -m
565 // If set more than once, they are set and printed in order:
566 // try ulimit -m -m 1000 -m -m 2000 -m -m 3000 -m
567 //
568 // Limits are shown in the order of options given:
569 // ulimit -m -f is not the same as ulimit -f -m.
570 //
571 // If both -S and -H are given, show soft limit.
572 //
573 // Short printout (limit value only) is printed only if just one option
574 // is given: ulimit -m. ulimit -f -m prints verbose lines.
575 // ulimit -f -f prints same verbose line twice.
576 // ulimit -m 10000 -f prints verbose line for -f.
577
578 argc = string_array_len(argv);
579
580 /* First pass over options: detect -H/-S/-a status,
581 * and "bare ulimit" and "only one option" cases
582 * by counting other opts.
583 */
584 opt_cnt = 0;
585 opts = 0;
586 while (1) {
587 int opt_char = getopt(argc, argv, ulimit_opt_string);
588
589 if (opt_char == -1)
590 break;
591 if (opt_char == 'H') {
592 opts |= OPT_hard;
593 continue;
594 }
595 if (opt_char == 'S') {
596 opts |= OPT_soft;
597 continue;
598 }
599 if (opt_char == 'a') {
600 opts |= OPT_all;
601 continue;
602 }
603 if (opt_char == '?') {
604 /* bad option. getopt already complained. */
605 return EXIT_FAILURE;
606 }
607 opt_cnt++;
608 } /* while (there are options) */
609
610 if (!(opts & (OPT_hard | OPT_soft)))
611 opts |= (OPT_hard | OPT_soft);
612 if (opts & OPT_all) {
613 const char *help = limits_help;
614 for (i = 0; i < ARRAY_SIZE(limits_tbl); i++) {
615 getrlimit(limits_tbl[i].cmd, &limit);
616 printf("%-32s(-%c) ", help, limit_chars[i]);
617 printlim(opts, &limit, &limits_tbl[i]);
618 help += strlen(help) + 1;
619 }
620 return EXIT_SUCCESS;
621 }
622
623 /* Second pass: set or print limits, in order */
624 GETOPT_RESET();
625 while (1) {
626 char *val_str;
627 int opt_char = getopt(argc, argv, ulimit_opt_string);
628
629 if (opt_char == -1)
630 break;
631 if (opt_char == 'H')
632 continue;
633 if (opt_char == 'S')
634 continue;
635 //if (opt_char == 'a') - impossible
636
637 if (opt_char == 1) /* if "ulimit NNN", -f is assumed */
638 opt_char = 'f';
639 i = strchrnul(limit_chars, opt_char) - limit_chars;
640 //if (i >= ARRAY_SIZE(limits_tbl)) - bad option, impossible
641
642 val_str = optarg;
643 if (!val_str && argv[optind] && argv[optind][0] != '-')
644 val_str = argv[optind++]; /* ++ skips NN in "-c NN" case */
645
646 getrlimit(limits_tbl[i].cmd, &limit);
647 if (!val_str) {
648 if (opt_cnt > 1)
649 printf("%-32s(-%c) ", nth_string(limits_help, i), limit_chars[i]);
650 printlim(opts, &limit, &limits_tbl[i]);
651 } else {
652 rlim_t val = RLIM_INFINITY;
653 if (strcmp(val_str, "unlimited") != 0) {
654 if (sizeof(val) == sizeof(int))
655 val = bb_strtou(val_str, NULL, 10);
656 else if (sizeof(val) == sizeof(long))
657 val = bb_strtoul(val_str, NULL, 10);
658 else
659 val = bb_strtoull(val_str, NULL, 10);
660 if (errno) {
661 bb_error_msg("invalid number '%s'", val_str);
662 return EXIT_FAILURE;
663 }
664 val <<= limits_tbl[i].factor_shift;
665 }
666 //bb_error_msg("opt %c val_str:'%s' val:%lld", opt_char, val_str, (long long)val);
667 /* from man bash: "If neither -H nor -S
668 * is specified, both the soft and hard
669 * limits are set. */
670 if (opts & OPT_hard)
671 limit.rlim_max = val;
672 if (opts & OPT_soft)
673 limit.rlim_cur = val;
674 //bb_error_msg("setrlimit(%d, %lld, %lld)", limits_tbl[i].cmd, (long long)limit.rlim_cur, (long long)limit.rlim_max);
675 if (setrlimit(limits_tbl[i].cmd, &limit) < 0) {
676 bb_simple_perror_msg("error setting limit");
677 return EXIT_FAILURE;
678 }
679 }
680 } /* while (there are options) */
681
682 if (opt_cnt == 0) {
683 /* "bare ulimit": treat it as if it was -f */
684 getrlimit(RLIMIT_FSIZE, &limit);
685 printlim(opts, &limit, &limits_tbl[LIMIT_F_IDX]);
686 }
687
688 return EXIT_SUCCESS;
689 }
690