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path: root/shell/shell_common.c (plain)
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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#include <sys/resource.h> /* getrlimit */
22
23const char defifsvar[] ALIGN1 = "IFS= \t\n";
24const char defoptindvar[] ALIGN1 = "OPTIND=1";
25
26
27int FAST_FUNC is_well_formed_var_name(const char *s, char terminator)
28{
29 if (!s || !(isalpha(*s) || *s == '_'))
30 return 0;
31
32 do
33 s++;
34 while (isalnum(*s) || *s == '_');
35
36 return *s == terminator;
37}
38
39/* read builtin */
40
41/* Needs to be interruptible: shell must handle traps and shell-special signals
42 * while inside read. To implement this, be sure to not loop on EINTR
43 * and return errno == EINTR reliably.
44 */
45//TODO: use more efficient setvar() which takes a pointer to malloced "VAR=VAL"
46//string. hush naturally has it, and ash has setvareq().
47//Here we can simply store "VAR=" at buffer start and store read data directly
48//after "=", then pass buffer to setvar() to consume.
49const char* FAST_FUNC
50shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
51 char **argv,
52 const char *ifs,
53 int read_flags,
54 const char *opt_n,
55 const char *opt_p,
56 const char *opt_t,
57 const char *opt_u
58)
59{
60 unsigned err;
61 unsigned end_ms; /* -t TIMEOUT */
62 int fd; /* -u FD */
63 int nchars; /* -n NUM */
64 char **pp;
65 char *buffer;
66 struct termios tty, old_tty;
67 const char *retval;
68 int bufpos; /* need to be able to hold -1 */
69 int startword;
70 smallint backslash;
71
72 errno = err = 0;
73
74 pp = argv;
75 while (*pp) {
76 if (!is_well_formed_var_name(*pp, '\0')) {
77 /* Mimic bash message */
78 bb_error_msg("read: '%s': not a valid identifier", *pp);
79 return (const char *)(uintptr_t)1;
80 }
81 pp++;
82 }
83
84 nchars = 0; /* if != 0, -n is in effect */
85 if (opt_n) {
86 nchars = bb_strtou(opt_n, NULL, 10);
87 if (nchars < 0 || errno)
88 return "invalid count";
89 /* note: "-n 0": off (bash 3.2 does this too) */
90 }
91 end_ms = 0;
92 if (opt_t) {
93 end_ms = bb_strtou(opt_t, NULL, 10);
94 if (errno || end_ms > UINT_MAX / 2048)
95 return "invalid timeout";
96 end_ms *= 1000;
97#if 0 /* even bash has no -t N.NNN support */
98 ts.tv_sec = bb_strtou(opt_t, &p, 10);
99 ts.tv_usec = 0;
100 /* EINVAL means number is ok, but not terminated by NUL */
101 if (*p == '.' && errno == EINVAL) {
102 char *p2;
103 if (*++p) {
104 int scale;
105 ts.tv_usec = bb_strtou(p, &p2, 10);
106 if (errno)
107 return "invalid timeout";
108 scale = p2 - p;
109 /* normalize to usec */
110 if (scale > 6)
111 return "invalid timeout";
112 while (scale++ < 6)
113 ts.tv_usec *= 10;
114 }
115 } else if (ts.tv_sec < 0 || errno) {
116 return "invalid timeout";
117 }
118 if (!(ts.tv_sec | ts.tv_usec)) { /* both are 0? */
119 return "invalid timeout";
120 }
121#endif /* if 0 */
122 }
123 fd = STDIN_FILENO;
124 if (opt_u) {
125 fd = bb_strtou(opt_u, NULL, 10);
126 if (fd < 0 || errno)
127 return "invalid file descriptor";
128 }
129
130 if (opt_p && isatty(fd)) {
131 fputs(opt_p, stderr);
132 fflush_all();
133 }
134
135 if (ifs == NULL)
136 ifs = defifs;
137
138 if (nchars || (read_flags & BUILTIN_READ_SILENT)) {
139 tcgetattr(fd, &tty);
140 old_tty = tty;
141 if (nchars) {
142 tty.c_lflag &= ~ICANON;
143 // Setting it to more than 1 breaks poll():
144 // it blocks even if there's data. !??
145 //tty.c_cc[VMIN] = nchars < 256 ? nchars : 255;
146 /* reads would block only if < 1 char is available */
147 tty.c_cc[VMIN] = 1;
148 /* no timeout (reads block forever) */
149 tty.c_cc[VTIME] = 0;
150 }
151 if (read_flags & BUILTIN_READ_SILENT) {
152 tty.c_lflag &= ~(ECHO | ECHOK | ECHONL);
153 }
154 /* This forces execution of "restoring" tcgetattr later */
155 read_flags |= BUILTIN_READ_SILENT;
156 /* if tcgetattr failed, tcsetattr will fail too.
157 * Ignoring, it's harmless. */
158 tcsetattr(fd, TCSANOW, &tty);
159 }
160
161 retval = (const char *)(uintptr_t)0;
162 startword = 1;
163 backslash = 0;
164 if (end_ms) /* NB: end_ms stays nonzero: */
165 end_ms = ((unsigned)monotonic_ms() + end_ms) | 1;
166 buffer = NULL;
167 bufpos = 0;
168 do {
169 char c;
170 struct pollfd pfd[1];
171 int timeout;
172
173 if ((bufpos & 0xff) == 0)
174 buffer = xrealloc(buffer, bufpos + 0x101);
175
176 timeout = -1;
177 if (end_ms) {
178 timeout = end_ms - (unsigned)monotonic_ms();
179 if (timeout <= 0) { /* already late? */
180 retval = (const char *)(uintptr_t)1;
181 goto ret;
182 }
183 }
184
185 /* We must poll even if timeout is -1:
186 * we want to be interrupted if signal arrives,
187 * regardless of SA_RESTART-ness of that signal!
188 */
189 errno = 0;
190 pfd[0].fd = fd;
191 pfd[0].events = POLLIN;
192 if (poll(pfd, 1, timeout) != 1) {
193 /* timed out, or EINTR */
194 err = errno;
195 retval = (const char *)(uintptr_t)1;
196 goto ret;
197 }
198 if (read(fd, &buffer[bufpos], 1) != 1) {
199 err = errno;
200 retval = (const char *)(uintptr_t)1;
201 break;
202 }
203
204 c = buffer[bufpos];
205 if (c == '\0')
206 continue;
207 if (backslash) {
208 backslash = 0;
209 if (c != '\n')
210 goto put;
211 continue;
212 }
213 if (!(read_flags & BUILTIN_READ_RAW) && c == '\\') {
214 backslash = 1;
215 continue;
216 }
217 if (c == '\n')
218 break;
219
220 /* $IFS splitting. NOT done if we run "read"
221 * without variable names (bash compat).
222 * Thus, "read" and "read REPLY" are not the same.
223 */
224 if (argv[0]) {
225/* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_05 */
226 const char *is_ifs = strchr(ifs, c);
227 if (startword && is_ifs) {
228 if (isspace(c))
229 continue;
230 /* it is a non-space ifs char */
231 startword--;
232 if (startword == 1) /* first one? */
233 continue; /* yes, it is not next word yet */
234 }
235 startword = 0;
236 if (argv[1] != NULL && is_ifs) {
237 buffer[bufpos] = '\0';
238 bufpos = 0;
239 setvar(*argv, buffer);
240 argv++;
241 /* can we skip one non-space ifs char? (2: yes) */
242 startword = isspace(c) ? 2 : 1;
243 continue;
244 }
245 }
246 put:
247 bufpos++;
248 } while (--nchars);
249
250 if (argv[0]) {
251 /* Remove trailing space $IFS chars */
252 while (--bufpos >= 0 && isspace(buffer[bufpos]) && strchr(ifs, buffer[bufpos]) != NULL)
253 continue;
254 buffer[bufpos + 1] = '\0';
255 /* Use the remainder as a value for the next variable */
256 setvar(*argv, buffer);
257 /* Set the rest to "" */
258 while (*++argv)
259 setvar(*argv, "");
260 } else {
261 /* Note: no $IFS removal */
262 buffer[bufpos] = '\0';
263 setvar("REPLY", buffer);
264 }
265
266 ret:
267 free(buffer);
268 if (read_flags & BUILTIN_READ_SILENT)
269 tcsetattr(fd, TCSANOW, &old_tty);
270
271 errno = err;
272 return retval;
273}
274
275/* ulimit builtin */
276
277struct limits {
278 uint8_t cmd; /* RLIMIT_xxx fit into it */
279 uint8_t factor_shift; /* shift by to get rlim_{cur,max} values */
280 char option;
281 const char *name;
282};
283
284static const struct limits limits_tbl[] = {
285#ifdef RLIMIT_FSIZE
286 { RLIMIT_FSIZE, 9, 'f', "file size (blocks)" },
287#endif
288#ifdef RLIMIT_CPU
289 { RLIMIT_CPU, 0, 't', "cpu time (seconds)" },
290#endif
291#ifdef RLIMIT_DATA
292 { RLIMIT_DATA, 10, 'd', "data seg size (kb)" },
293#endif
294#ifdef RLIMIT_STACK
295 { RLIMIT_STACK, 10, 's', "stack size (kb)" },
296#endif
297#ifdef RLIMIT_CORE
298 { RLIMIT_CORE, 9, 'c', "core file size (blocks)" },
299#endif
300#ifdef RLIMIT_RSS
301 { RLIMIT_RSS, 10, 'm', "resident set size (kb)" },
302#endif
303#ifdef RLIMIT_MEMLOCK
304 { RLIMIT_MEMLOCK, 10, 'l', "locked memory (kb)" },
305#endif
306#ifdef RLIMIT_NPROC
307 { RLIMIT_NPROC, 0, 'p', "processes" },
308#endif
309#ifdef RLIMIT_NOFILE
310 { RLIMIT_NOFILE, 0, 'n', "file descriptors" },
311#endif
312#ifdef RLIMIT_AS
313 { RLIMIT_AS, 10, 'v', "address space (kb)" },
314#endif
315#ifdef RLIMIT_LOCKS
316 { RLIMIT_LOCKS, 0, 'w', "locks" },
317#endif
318#ifdef RLIMIT_NICE
319 { RLIMIT_NICE, 0, 'e', "scheduling priority" },
320#endif
321#ifdef RLIMIT_RTPRIO
322 { RLIMIT_RTPRIO, 0, 'r', "real-time priority" },
323#endif
324};
325
326enum {
327 OPT_hard = (1 << 0),
328 OPT_soft = (1 << 1),
329};
330
331/* "-": treat args as parameters of option with ASCII code 1 */
332static const char ulimit_opt_string[] ALIGN1 = "-HSa"
333#ifdef RLIMIT_FSIZE
334 "f::"
335#endif
336#ifdef RLIMIT_CPU
337 "t::"
338#endif
339#ifdef RLIMIT_DATA
340 "d::"
341#endif
342#ifdef RLIMIT_STACK
343 "s::"
344#endif
345#ifdef RLIMIT_CORE
346 "c::"
347#endif
348#ifdef RLIMIT_RSS
349 "m::"
350#endif
351#ifdef RLIMIT_MEMLOCK
352 "l::"
353#endif
354#ifdef RLIMIT_NPROC
355 "p::"
356#endif
357#ifdef RLIMIT_NOFILE
358 "n::"
359#endif
360#ifdef RLIMIT_AS
361 "v::"
362#endif
363#ifdef RLIMIT_LOCKS
364 "w::"
365#endif
366#ifdef RLIMIT_NICE
367 "e::"
368#endif
369#ifdef RLIMIT_RTPRIO
370 "r::"
371#endif
372 ;
373
374static void printlim(unsigned opts, const struct rlimit *limit,
375 const struct limits *l)
376{
377 rlim_t val;
378
379 val = limit->rlim_max;
380 if (!(opts & OPT_hard))
381 val = limit->rlim_cur;
382
383 if (val == RLIM_INFINITY)
384 puts("unlimited");
385 else {
386 val >>= l->factor_shift;
387 printf("%llu\n", (long long) val);
388 }
389}
390
391int FAST_FUNC
392shell_builtin_ulimit(char **argv)
393{
394 unsigned opts;
395 unsigned argc;
396
397 /* We can't use getopt32: need to handle commands like
398 * ulimit 123 -c2 -l 456
399 */
400
401 /* In case getopt was already called:
402 * reset the libc getopt() function, which keeps internal state.
403 */
404#ifdef __GLIBC__
405 optind = 0;
406#else /* BSD style */
407 optind = 1;
408 /* optreset = 1; */
409#endif
410 /* optarg = NULL; opterr = 0; optopt = 0; - do we need this?? */
411
412 argc = 1;
413 while (argv[argc])
414 argc++;
415
416 opts = 0;
417 while (1) {
418 struct rlimit limit;
419 const struct limits *l;
420 int opt_char = getopt(argc, argv, ulimit_opt_string);
421
422 if (opt_char == -1)
423 break;
424 if (opt_char == 'H') {
425 opts |= OPT_hard;
426 continue;
427 }
428 if (opt_char == 'S') {
429 opts |= OPT_soft;
430 continue;
431 }
432
433 if (opt_char == 'a') {
434 for (l = limits_tbl; l != &limits_tbl[ARRAY_SIZE(limits_tbl)]; l++) {
435 getrlimit(l->cmd, &limit);
436 printf("-%c: %-30s ", l->option, l->name);
437 printlim(opts, &limit, l);
438 }
439 continue;
440 }
441
442 if (opt_char == 1)
443 opt_char = 'f';
444 for (l = limits_tbl; l != &limits_tbl[ARRAY_SIZE(limits_tbl)]; l++) {
445 if (opt_char == l->option) {
446 char *val_str;
447
448 getrlimit(l->cmd, &limit);
449
450 val_str = optarg;
451 if (!val_str && argv[optind] && argv[optind][0] != '-')
452 val_str = argv[optind++]; /* ++ skips NN in "-c NN" case */
453 if (val_str) {
454 rlim_t val;
455
456 if (strcmp(val_str, "unlimited") == 0)
457 val = RLIM_INFINITY;
458 else {
459 if (sizeof(val) == sizeof(int))
460 val = bb_strtou(val_str, NULL, 10);
461 else if (sizeof(val) == sizeof(long))
462 val = bb_strtoul(val_str, NULL, 10);
463 else
464 val = bb_strtoull(val_str, NULL, 10);
465 if (errno) {
466 bb_error_msg("invalid number '%s'", val_str);
467 return EXIT_FAILURE;
468 }
469 val <<= l->factor_shift;
470 }
471//bb_error_msg("opt %c val_str:'%s' val:%lld", opt_char, val_str, (long long)val);
472 /* from man bash: "If neither -H nor -S
473 * is specified, both the soft and hard
474 * limits are set. */
475 if (!opts)
476 opts = OPT_hard + OPT_soft;
477 if (opts & OPT_hard)
478 limit.rlim_max = val;
479 if (opts & OPT_soft)
480 limit.rlim_cur = val;
481//bb_error_msg("setrlimit(%d, %lld, %lld)", l->cmd, (long long)limit.rlim_cur, (long long)limit.rlim_max);
482 if (setrlimit(l->cmd, &limit) < 0) {
483 bb_perror_msg("error setting limit");
484 return EXIT_FAILURE;
485 }
486 } else {
487 printlim(opts, &limit, l);
488 }
489 break;
490 }
491 } /* for (every possible opt) */
492
493 if (l == &limits_tbl[ARRAY_SIZE(limits_tbl)]) {
494 /* bad option. getopt already complained. */
495 break;
496 }
497 } /* while (there are options) */
498
499 return 0;
500}
501
generated by cgit at 2024-05-15 09:14:25 (GMT)