1 /* vi: set sw=4 ts=4: */
3 * Adapted from ash applet code
5 * This code is derived from software contributed to Berkeley by
8 * Copyright (c) 1989, 1991, 1993, 1994
9 * The Regents of the University of California. All rights reserved.
11 * Copyright (c) 1997-2005 Herbert Xu <herbert@gondor.apana.org.au>
12 * was re-ported from NetBSD and debianized.
14 * Copyright (c) 2010 Denys Vlasenko
17 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
20 #include "shell_common.h"
22 const char defifsvar[] ALIGN1 = "IFS= \t\n";
23 const char defoptindvar[] ALIGN1 = "OPTIND=1";
26 int FAST_FUNC is_well_formed_var_name(const char *s, char terminator)
28 if (!s || !(isalpha(*s) || *s == '_'))
33 while (isalnum(*s) || *s == '_');
35 return *s == terminator;
40 /* Needs to be interruptible: shell must handle traps and shell-special signals
41 * while inside read. To implement this, be sure to not loop on EINTR
42 * and return errno == EINTR reliably.
44 //TODO: use more efficient setvar() which takes a pointer to malloced "VAR=VAL"
45 //string. hush naturally has it, and ash has setvareq().
46 //Here we can simply store "VAR=" at buffer start and store read data directly
47 //after "=", then pass buffer to setvar() to consume.
49 shell_builtin_read(struct builtin_read_params *params)
52 #define fd (pfd[0].fd) /* -u FD */
54 unsigned end_ms; /* -t TIMEOUT */
55 int nchars; /* -n NUM */
59 struct termios tty, old_tty;
61 int bufpos; /* need to be able to hold -1 */
73 if (!is_well_formed_var_name(*pp, '\0')) {
74 /* Mimic bash message */
75 bb_error_msg("read: '%s': not a valid identifier", *pp);
76 return (const char *)(uintptr_t)1;
81 nchars = 0; /* if != 0, -n is in effect */
83 nchars = bb_strtou(params->opt_n, NULL, 10);
84 if (nchars < 0 || errno)
85 return "invalid count";
86 /* note: "-n 0": off (bash 3.2 does this too) */
90 if (params->opt_t && !ENABLE_FEATURE_SH_READ_FRAC) {
91 end_ms = bb_strtou(params->opt_t, NULL, 10);
93 return "invalid timeout";
94 if (end_ms > UINT_MAX / 2048) /* be safely away from overflow */
95 end_ms = UINT_MAX / 2048;
98 if (params->opt_t && ENABLE_FEATURE_SH_READ_FRAC) {
99 /* bash 4.3 (maybe earlier) supports -t N.NNNNNN */
101 /* Eat up to three fractional digits */
102 int frac_digits = 3 + 1;
104 end_ms = bb_strtou(params->opt_t, &p, 10);
105 if (end_ms > UINT_MAX / 2048) /* be safely away from overflow */
106 end_ms = UINT_MAX / 2048;
109 /* EINVAL = number is ok, but not NUL terminated */
110 if (errno != EINVAL || *p != '.')
111 return "invalid timeout";
112 /* Do not check the rest: bash allows "0.123456xyz" */
113 while (*++p && --frac_digits) {
115 end_ms += (*p - '0');
116 if ((unsigned char)(*p - '0') > 9)
117 return "invalid timeout";
120 while (--frac_digits > 0) {
127 fd = bb_strtou(params->opt_u, NULL, 10);
129 return "invalid file descriptor";
132 if (params->opt_t && end_ms == 0) {
133 /* "If timeout is 0, read returns immediately, without trying
134 * to read any data. The exit status is 0 if input is available
135 * on the specified file descriptor, non-zero otherwise."
136 * bash seems to ignore -p PROMPT for this use case.
139 pfd[0].events = POLLIN;
140 r = poll(pfd, 1, /*timeout:*/ 0);
141 /* Return 0 only if poll returns 1 ("one fd ready"), else return 1: */
142 return (const char *)(uintptr_t)(r <= 0);
145 if (params->opt_p && isatty(fd)) {
146 fputs(params->opt_p, stderr);
154 read_flags = params->read_flags;
155 if (nchars || (read_flags & BUILTIN_READ_SILENT)) {
159 tty.c_lflag &= ~ICANON;
160 // Setting it to more than 1 breaks poll():
161 // it blocks even if there's data. !??
162 //tty.c_cc[VMIN] = nchars < 256 ? nchars : 255;
163 /* reads will block only if < 1 char is available */
165 /* no timeout (reads block forever) */
168 if (read_flags & BUILTIN_READ_SILENT) {
169 tty.c_lflag &= ~(ECHO | ECHOK | ECHONL);
171 /* This forces execution of "restoring" tcgetattr later */
172 read_flags |= BUILTIN_READ_SILENT;
173 /* if tcgetattr failed, tcsetattr will fail too.
174 * Ignoring, it's harmless. */
175 tcsetattr(fd, TCSANOW, &tty);
178 retval = (const char *)(uintptr_t)0;
182 end_ms += (unsigned)monotonic_ms();
185 delim = params->opt_d ? params->opt_d[0] : '\n';
190 if ((bufpos & 0xff) == 0)
191 buffer = xrealloc(buffer, bufpos + 0x101);
195 timeout = end_ms - (unsigned)monotonic_ms();
196 /* ^^^^^^^^^^^^^ all values are unsigned,
197 * wrapping math is used here, good even if
198 * 32-bit unix time wrapped (year 2038+).
200 if (timeout <= 0) { /* already late? */
201 retval = (const char *)(uintptr_t)1;
206 /* We must poll even if timeout is -1:
207 * we want to be interrupted if signal arrives,
208 * regardless of SA_RESTART-ness of that signal!
211 pfd[0].events = POLLIN;
212 if (poll(pfd, 1, timeout) <= 0) {
213 /* timed out, or EINTR */
215 retval = (const char *)(uintptr_t)1;
218 if (read(fd, &buffer[bufpos], 1) != 1) {
220 retval = (const char *)(uintptr_t)1;
227 if (!(read_flags & BUILTIN_READ_RAW)) {
239 if (c == delim) /* '\n' or -d CHAR */
242 /* $IFS splitting. NOT done if we run "read"
243 * without variable names (bash compat).
244 * Thus, "read" and "read REPLY" are not the same.
246 if (!params->opt_d && argv[0]) {
247 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_05 */
248 const char *is_ifs = strchr(ifs, c);
249 if (startword && is_ifs) {
252 /* it is a non-space ifs char */
254 if (startword == 1) /* first one? */
255 continue; /* yes, it is not next word yet */
258 if (argv[1] != NULL && is_ifs) {
259 buffer[bufpos] = '\0';
261 params->setvar(*argv, buffer);
263 /* can we skip one non-space ifs char? (2: yes) */
264 startword = isspace(c) ? 2 : 1;
273 /* Remove trailing space $IFS chars */
275 && isspace(buffer[bufpos])
276 && strchr(ifs, buffer[bufpos]) != NULL
280 buffer[bufpos + 1] = '\0';
282 /* Last variable takes the entire remainder with delimiters
283 * (sans trailing whitespace $IFS),
284 * but ***only "if there are fewer vars than fields"(c)***!
285 * The "X:Y:" case below: there are two fields,
286 * and therefore last delimiter (:) is eaten:
288 * echo "X:Y:Z:" | (read x y; echo "|$x|$y|") # |X|Y:Z:|
289 * echo "X:Y:Z" | (read x y; echo "|$x|$y|") # |X|Y:Z|
290 * echo "X:Y:" | (read x y; echo "|$x|$y|") # |X|Y|, not |X|Y:|
291 * echo "X:Y : " | (read x y; echo "|$x|$y|") # |X|Y|
294 && strchr(ifs, buffer[bufpos]) != NULL
296 /* There _is_ a non-whitespace IFS char */
297 /* Skip whitespace IFS char before it */
299 && isspace(buffer[bufpos])
300 && strchr(ifs, buffer[bufpos]) != NULL
304 /* Are there $IFS chars? */
305 if (strcspn(buffer, ifs) >= ++bufpos) {
306 /* No: last var takes one field, not more */
307 /* So, drop trailing IFS delims */
308 buffer[bufpos] = '\0';
312 /* Use the remainder as a value for the next variable */
313 params->setvar(*argv, buffer);
314 /* Set the rest to "" */
316 params->setvar(*argv, "");
318 /* Note: no $IFS removal */
319 buffer[bufpos] = '\0';
320 params->setvar("REPLY", buffer);
325 if (read_flags & BUILTIN_READ_SILENT)
326 tcsetattr(fd, TCSANOW, &old_tty);
336 uint8_t cmd; /* RLIMIT_xxx fit into it */
337 uint8_t factor_shift; /* shift by to get rlim_{cur,max} values */
341 static const struct limits limits_tbl[] = {
342 /* No RLIMIT_FSIZE define guard since -f is the default limit and this must exist */
343 { RLIMIT_FSIZE, 9, "file size (blocks)" }, // -f
345 { RLIMIT_CPU, 0, "cpu time (seconds)" }, // -t
348 { RLIMIT_DATA, 10, "data seg size (kb)" }, // -d
351 { RLIMIT_STACK, 10, "stack size (kb)" }, // -s
354 { RLIMIT_CORE, 9, "core file size (blocks)" }, // -c
357 { RLIMIT_RSS, 10, "resident set size (kb)" }, // -m
359 #ifdef RLIMIT_MEMLOCK
360 { RLIMIT_MEMLOCK, 10, "locked memory (kb)" }, // -l
363 { RLIMIT_NPROC, 0, "processes" }, // -p
366 { RLIMIT_NOFILE, 0, "file descriptors" }, // -n
369 { RLIMIT_AS, 10, "address space (kb)" }, // -v
372 { RLIMIT_LOCKS, 0, "locks" }, // -w
375 { RLIMIT_NICE, 0, "scheduling priority" }, // -e
378 { RLIMIT_RTPRIO, 0, "real-time priority" }, // -r
382 static const char limit_chars[] ALIGN1 =
399 #ifdef RLIMIT_MEMLOCK
422 /* "-": treat args as parameters of option with ASCII code 1 */
423 static const char ulimit_opt_string[] ALIGN1 = "-HSa"
440 #ifdef RLIMIT_MEMLOCK
469 static void printlim(unsigned opts, const struct rlimit *limit,
470 const struct limits *l)
474 val = limit->rlim_max;
476 val = limit->rlim_cur;
478 if (val == RLIM_INFINITY)
481 val >>= l->factor_shift;
482 printf("%llu\n", (long long) val);
487 shell_builtin_ulimit(char **argv)
495 /* We can't use getopt32: need to handle commands like
496 * ulimit 123 -c2 -l 456
499 /* In case getopt() was already called:
500 * reset libc getopt() internal state.
506 // -H and/or -S change meaning even of options *before* them: ulimit -f 2000 -H
507 // sets hard limit, ulimit -a -H prints hard limits.
509 // -a is equivalent for requesting all limits to be shown.
511 // If -a is specified, attempts to set limits are ignored:
512 // ulimit -m 1000; ulimit -m 2000 -a
513 // shows 1000, not 2000. HOWEVER, *implicit* -f form "ulimit 2000 -a"
514 // DOES set -f limit [we don't implement this quirk], "ulimit -a 2000" does not.
515 // Options are still parsed: ulimit -az complains about unknown -z opt.
517 // -a is not cumulative: "ulimit -a -a" = "ulimit -a -f -m" = "ulimit -a"
519 // -HSa can be combined in one argument and with one other option (example: -Sm),
520 // but other options can't: limit value is an optional argument,
521 // thus "-mf" means "-m f", f is the parameter of -m.
523 // Limit can be set and then printed: ulimit -m 2000 -m
524 // If set more than once, they are set and printed in order:
525 // try ulimit -m -m 1000 -m -m 2000 -m -m 3000 -m
527 // Limits are shown in the order of options given:
528 // ulimit -m -f is not the same as ulimit -f -m.
530 // If both -S and -H are given, show soft limit.
532 // Short printout (limit value only) is printed only if just one option
533 // is given: ulimit -m. ulimit -f -m prints verbose lines.
534 // ulimit -f -f prints same verbose line twice.
535 // ulimit -m 10000 -f prints verbose line for -f.
537 argc = string_array_len(argv);
539 /* First pass over options: detect -H/-S/-a status,
540 * and "bare ulimit" and "only one option" cases
541 * by counting other opts.
546 int opt_char = getopt(argc, argv, ulimit_opt_string);
550 if (opt_char == 'H') {
554 if (opt_char == 'S') {
558 if (opt_char == 'a') {
562 if (opt_char == '?') {
563 /* bad option. getopt already complained. */
567 } /* while (there are options) */
569 if (!(opts & (OPT_hard | OPT_soft)))
570 opts |= (OPT_hard | OPT_soft);
571 if (opts & OPT_all) {
572 for (i = 0; i < ARRAY_SIZE(limits_tbl); i++) {
573 getrlimit(limits_tbl[i].cmd, &limit);
574 printf("-%c: %-30s ", limit_chars[i], limits_tbl[i].name);
575 printlim(opts, &limit, &limits_tbl[i]);
580 /* Second pass: set or print limits, in order */
584 int opt_char = getopt(argc, argv, ulimit_opt_string);
592 //if (opt_char == 'a') - impossible
594 i = 0; /* if "ulimit NNN", -f is assumed */
596 i = strchrnul(limit_chars, opt_char) - limit_chars;
597 //if (i >= ARRAY_SIZE(limits_tbl)) - bad option, impossible
601 if (!val_str && argv[optind] && argv[optind][0] != '-')
602 val_str = argv[optind++]; /* ++ skips NN in "-c NN" case */
604 getrlimit(limits_tbl[i].cmd, &limit);
607 printf("-%c: %-30s ", limit_chars[i], limits_tbl[i].name);
608 printlim(opts, &limit, &limits_tbl[i]);
610 rlim_t val = RLIM_INFINITY;
611 if (strcmp(val_str, "unlimited") != 0) {
612 if (sizeof(val) == sizeof(int))
613 val = bb_strtou(val_str, NULL, 10);
614 else if (sizeof(val) == sizeof(long))
615 val = bb_strtoul(val_str, NULL, 10);
617 val = bb_strtoull(val_str, NULL, 10);
619 bb_error_msg("invalid number '%s'", val_str);
622 val <<= limits_tbl[i].factor_shift;
624 //bb_error_msg("opt %c val_str:'%s' val:%lld", opt_char, val_str, (long long)val);
625 /* from man bash: "If neither -H nor -S
626 * is specified, both the soft and hard
629 limit.rlim_max = val;
631 limit.rlim_cur = val;
632 //bb_error_msg("setrlimit(%d, %lld, %lld)", limits_tbl[i].cmd, (long long)limit.rlim_cur, (long long)limit.rlim_max);
633 if (setrlimit(limits_tbl[i].cmd, &limit) < 0) {
634 bb_perror_msg("error setting limit");
638 } /* while (there are options) */
641 /* "bare ulimit": treat it as if it was -f */
642 getrlimit(limits_tbl[0].cmd, &limit);
643 printlim(opts, &limit, &limits_tbl[0]);