source: MondoRescue/branches/3.2/mindi-busybox/findutils/xargs.c@ 3232

Last change on this file since 3232 was 3232, checked in by Bruno Cornec, 10 years ago
  • Update mindi-busybox to 1.21.1
File size: 14.5 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * Mini xargs implementation for busybox
4 *
5 * (C) 2002,2003 by Vladimir Oleynik <dzo@simtreas.ru>
6 *
7 * Special thanks
8 * - Mark Whitley and Glenn McGrath for stimulus to rewrite :)
9 * - Mike Rendell <michael@cs.mun.ca>
10 * and David MacKenzie <djm@gnu.ai.mit.edu>.
11 *
12 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
13 *
14 * xargs is described in the Single Unix Specification v3 at
15 * http://www.opengroup.org/onlinepubs/007904975/utilities/xargs.html
16 */
17
18//config:config XARGS
19//config: bool "xargs"
20//config: default y
21//config: help
22//config: xargs is used to execute a specified command for
23//config: every item from standard input.
24//config:
25//config:config FEATURE_XARGS_SUPPORT_CONFIRMATION
26//config: bool "Enable -p: prompt and confirmation"
27//config: default y
28//config: depends on XARGS
29//config: help
30//config: Support -p: prompt the user whether to run each command
31//config: line and read a line from the terminal.
32//config:
33//config:config FEATURE_XARGS_SUPPORT_QUOTES
34//config: bool "Enable single and double quotes and backslash"
35//config: default y
36//config: depends on XARGS
37//config: help
38//config: Support quoting in the input.
39//config:
40//config:config FEATURE_XARGS_SUPPORT_TERMOPT
41//config: bool "Enable -x: exit if -s or -n is exceeded"
42//config: default y
43//config: depends on XARGS
44//config: help
45//config: Support -x: exit if the command size (see the -s or -n option)
46//config: is exceeded.
47//config:
48//config:config FEATURE_XARGS_SUPPORT_ZERO_TERM
49//config: bool "Enable -0: NUL-terminated input"
50//config: default y
51//config: depends on XARGS
52//config: help
53//config: Support -0: input items are terminated by a NUL character
54//config: instead of whitespace, and the quotes and backslash
55//config: are not special.
56
57//applet:IF_XARGS(APPLET_NOEXEC(xargs, xargs, BB_DIR_USR_BIN, BB_SUID_DROP, xargs))
58
59//kbuild:lib-$(CONFIG_XARGS) += xargs.o
60
61#include "libbb.h"
62
63/* This is a NOEXEC applet. Be very careful! */
64
65
66//#define dbg_msg(...) bb_error_msg(__VA_ARGS__)
67#define dbg_msg(...) ((void)0)
68
69
70#ifdef TEST
71# ifndef ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION
72# define ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION 1
73# endif
74# ifndef ENABLE_FEATURE_XARGS_SUPPORT_QUOTES
75# define ENABLE_FEATURE_XARGS_SUPPORT_QUOTES 1
76# endif
77# ifndef ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT
78# define ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT 1
79# endif
80# ifndef ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
81# define ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM 1
82# endif
83#endif
84
85
86struct globals {
87 char **args;
88 const char *eof_str;
89 int idx;
90} FIX_ALIASING;
91#define G (*(struct globals*)&bb_common_bufsiz1)
92#define INIT_G() do { \
93 G.eof_str = NULL; /* need to clear by hand because we are NOEXEC applet */ \
94} while (0)
95
96
97/*
98 * This function has special algorithm.
99 * Don't use fork and include to main!
100 */
101static int xargs_exec(void)
102{
103 int status;
104
105 status = spawn_and_wait(G.args);
106 if (status < 0) {
107 bb_simple_perror_msg(G.args[0]);
108 return errno == ENOENT ? 127 : 126;
109 }
110 if (status == 255) {
111 bb_error_msg("%s: exited with status 255; aborting", G.args[0]);
112 return 124;
113 }
114 if (status >= 0x180) {
115 bb_error_msg("%s: terminated by signal %d",
116 G.args[0], status - 0x180);
117 return 125;
118 }
119 if (status)
120 return 123;
121 return 0;
122}
123
124/* In POSIX/C locale isspace is only these chars: "\t\n\v\f\r" and space.
125 * "\t\n\v\f\r" happen to have ASCII codes 9,10,11,12,13.
126 */
127#define ISSPACE(a) ({ unsigned char xargs__isspace = (a) - 9; xargs__isspace == (' ' - 9) || xargs__isspace <= (13 - 9); })
128
129static void store_param(char *s)
130{
131 /* Grow by 256 elements at once */
132 if (!(G.idx & 0xff)) { /* G.idx == N*256 */
133 /* Enlarge, make G.args[(N+1)*256 - 1] last valid idx */
134 G.args = xrealloc(G.args, sizeof(G.args[0]) * (G.idx + 0x100));
135 }
136 G.args[G.idx++] = s;
137}
138
139/* process[0]_stdin:
140 * Read characters into buf[n_max_chars+1], and when parameter delimiter
141 * is seen, store the address of a new parameter to args[].
142 * If reading discovers that last chars do not form the complete
143 * parameter, the pointer to the first such "tail character" is returned.
144 * (buf has extra byte at the end to accomodate terminating NUL
145 * of "tail characters" string).
146 * Otherwise, the returned pointer points to NUL byte.
147 * On entry, buf[] may contain some "seed chars" which are to become
148 * the beginning of the first parameter.
149 */
150
151#if ENABLE_FEATURE_XARGS_SUPPORT_QUOTES
152static char* FAST_FUNC process_stdin(int n_max_chars, int n_max_arg, char *buf)
153{
154#define NORM 0
155#define QUOTE 1
156#define BACKSLASH 2
157#define SPACE 4
158 char q = '\0'; /* quote char */
159 char state = NORM;
160 char *s = buf; /* start of the word */
161 char *p = s + strlen(buf); /* end of the word */
162
163 buf += n_max_chars; /* past buffer's end */
164
165 /* "goto ret" is used instead of "break" to make control flow
166 * more obvious: */
167
168 while (1) {
169 int c = getchar();
170 if (c == EOF) {
171 if (p != s)
172 goto close_word;
173 goto ret;
174 }
175 if (state == BACKSLASH) {
176 state = NORM;
177 goto set;
178 }
179 if (state == QUOTE) {
180 if (c != q)
181 goto set;
182 q = '\0';
183 state = NORM;
184 } else { /* if (state == NORM) */
185 if (ISSPACE(c)) {
186 if (p != s) {
187 close_word:
188 state = SPACE;
189 c = '\0';
190 goto set;
191 }
192 } else {
193 if (c == '\\') {
194 state = BACKSLASH;
195 } else if (c == '\'' || c == '"') {
196 q = c;
197 state = QUOTE;
198 } else {
199 set:
200 *p++ = c;
201 }
202 }
203 }
204 if (state == SPACE) { /* word's delimiter or EOF detected */
205 if (q) {
206 bb_error_msg_and_die("unmatched %s quote",
207 q == '\'' ? "single" : "double");
208 }
209 /* A full word is loaded */
210 if (G.eof_str) {
211 if (strcmp(s, G.eof_str) == 0) {
212 while (getchar() != EOF)
213 continue;
214 p = s;
215 goto ret;
216 }
217 }
218 store_param(s);
219 dbg_msg("args[]:'%s'", s);
220 s = p;
221 n_max_arg--;
222 if (n_max_arg == 0) {
223 goto ret;
224 }
225 state = NORM;
226 }
227 if (p == buf) {
228 goto ret;
229 }
230 }
231 ret:
232 *p = '\0';
233 /* store_param(NULL) - caller will do it */
234 dbg_msg("return:'%s'", s);
235 return s;
236}
237#else
238/* The variant does not support single quotes, double quotes or backslash */
239static char* FAST_FUNC process_stdin(int n_max_chars, int n_max_arg, char *buf)
240{
241 char *s = buf; /* start of the word */
242 char *p = s + strlen(buf); /* end of the word */
243
244 buf += n_max_chars; /* past buffer's end */
245
246 while (1) {
247 int c = getchar();
248 if (c == EOF) {
249 if (p == s)
250 goto ret;
251 }
252 if (c == EOF || ISSPACE(c)) {
253 if (p == s)
254 continue;
255 c = EOF;
256 }
257 *p++ = (c == EOF ? '\0' : c);
258 if (c == EOF) { /* word's delimiter or EOF detected */
259 /* A full word is loaded */
260 if (G.eof_str) {
261 if (strcmp(s, G.eof_str) == 0) {
262 while (getchar() != EOF)
263 continue;
264 p = s;
265 goto ret;
266 }
267 }
268 store_param(s);
269 dbg_msg("args[]:'%s'", s);
270 s = p;
271 n_max_arg--;
272 if (n_max_arg == 0) {
273 goto ret;
274 }
275 }
276 if (p == buf) {
277 goto ret;
278 }
279 }
280 ret:
281 *p = '\0';
282 /* store_param(NULL) - caller will do it */
283 dbg_msg("return:'%s'", s);
284 return s;
285}
286#endif /* FEATURE_XARGS_SUPPORT_QUOTES */
287
288#if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
289static char* FAST_FUNC process0_stdin(int n_max_chars, int n_max_arg, char *buf)
290{
291 char *s = buf; /* start of the word */
292 char *p = s + strlen(buf); /* end of the word */
293
294 buf += n_max_chars; /* past buffer's end */
295
296 while (1) {
297 int c = getchar();
298 if (c == EOF) {
299 if (p == s)
300 goto ret;
301 c = '\0';
302 }
303 *p++ = c;
304 if (c == '\0') { /* word's delimiter or EOF detected */
305 /* A full word is loaded */
306 store_param(s);
307 dbg_msg("args[]:'%s'", s);
308 s = p;
309 n_max_arg--;
310 if (n_max_arg == 0) {
311 goto ret;
312 }
313 }
314 if (p == buf) {
315 goto ret;
316 }
317 }
318 ret:
319 *p = '\0';
320 /* store_param(NULL) - caller will do it */
321 dbg_msg("return:'%s'", s);
322 return s;
323}
324#endif /* FEATURE_XARGS_SUPPORT_ZERO_TERM */
325
326#if ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION
327/* Prompt the user for a response, and
328 if the user responds affirmatively, return true;
329 otherwise, return false. Uses "/dev/tty", not stdin. */
330static int xargs_ask_confirmation(void)
331{
332 FILE *tty_stream;
333 int c, savec;
334
335 tty_stream = xfopen_for_read(CURRENT_TTY);
336 fputs(" ?...", stderr);
337 fflush_all();
338 c = savec = getc(tty_stream);
339 while (c != EOF && c != '\n')
340 c = getc(tty_stream);
341 fclose(tty_stream);
342 return (savec == 'y' || savec == 'Y');
343}
344#else
345# define xargs_ask_confirmation() 1
346#endif
347
348//usage:#define xargs_trivial_usage
349//usage: "[OPTIONS] [PROG ARGS]"
350//usage:#define xargs_full_usage "\n\n"
351//usage: "Run PROG on every item given by stdin\n"
352//usage: IF_FEATURE_XARGS_SUPPORT_CONFIRMATION(
353//usage: "\n -p Ask user whether to run each command"
354//usage: )
355//usage: "\n -r Don't run command if input is empty"
356//usage: IF_FEATURE_XARGS_SUPPORT_ZERO_TERM(
357//usage: "\n -0 Input is separated by NUL characters"
358//usage: )
359//usage: "\n -t Print the command on stderr before execution"
360//usage: "\n -e[STR] STR stops input processing"
361//usage: "\n -n N Pass no more than N args to PROG"
362//usage: "\n -s N Pass command line of no more than N bytes"
363//usage: IF_FEATURE_XARGS_SUPPORT_TERMOPT(
364//usage: "\n -x Exit if size is exceeded"
365//usage: )
366//usage:#define xargs_example_usage
367//usage: "$ ls | xargs gzip\n"
368//usage: "$ find . -name '*.c' -print | xargs rm\n"
369
370/* Correct regardless of combination of CONFIG_xxx */
371enum {
372 OPTBIT_VERBOSE = 0,
373 OPTBIT_NO_EMPTY,
374 OPTBIT_UPTO_NUMBER,
375 OPTBIT_UPTO_SIZE,
376 OPTBIT_EOF_STRING,
377 OPTBIT_EOF_STRING1,
378 IF_FEATURE_XARGS_SUPPORT_CONFIRMATION(OPTBIT_INTERACTIVE,)
379 IF_FEATURE_XARGS_SUPPORT_TERMOPT( OPTBIT_TERMINATE ,)
380 IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( OPTBIT_ZEROTERM ,)
381
382 OPT_VERBOSE = 1 << OPTBIT_VERBOSE ,
383 OPT_NO_EMPTY = 1 << OPTBIT_NO_EMPTY ,
384 OPT_UPTO_NUMBER = 1 << OPTBIT_UPTO_NUMBER,
385 OPT_UPTO_SIZE = 1 << OPTBIT_UPTO_SIZE ,
386 OPT_EOF_STRING = 1 << OPTBIT_EOF_STRING , /* GNU: -e[<param>] */
387 OPT_EOF_STRING1 = 1 << OPTBIT_EOF_STRING1, /* SUS: -E<param> */
388 OPT_INTERACTIVE = IF_FEATURE_XARGS_SUPPORT_CONFIRMATION((1 << OPTBIT_INTERACTIVE)) + 0,
389 OPT_TERMINATE = IF_FEATURE_XARGS_SUPPORT_TERMOPT( (1 << OPTBIT_TERMINATE )) + 0,
390 OPT_ZEROTERM = IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( (1 << OPTBIT_ZEROTERM )) + 0,
391};
392#define OPTION_STR "+trn:s:e::E:" \
393 IF_FEATURE_XARGS_SUPPORT_CONFIRMATION("p") \
394 IF_FEATURE_XARGS_SUPPORT_TERMOPT( "x") \
395 IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( "0")
396
397int xargs_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
398int xargs_main(int argc, char **argv)
399{
400 int i;
401 int child_error = 0;
402 char *max_args;
403 char *max_chars;
404 char *buf;
405 unsigned opt;
406 int n_max_chars;
407 int n_max_arg;
408#if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
409 char* FAST_FUNC (*read_args)(int, int, char*) = process_stdin;
410#else
411#define read_args process_stdin
412#endif
413
414 INIT_G();
415
416#if ENABLE_DESKTOP && ENABLE_LONG_OPTS
417 /* For example, Fedora's build system uses --no-run-if-empty */
418 applet_long_options =
419 "no-run-if-empty\0" No_argument "r"
420 ;
421#endif
422 opt = getopt32(argv, OPTION_STR, &max_args, &max_chars, &G.eof_str, &G.eof_str);
423
424 /* -E ""? You may wonder why not just omit -E?
425 * This is used for portability:
426 * old xargs was using "_" as default for -E / -e */
427 if ((opt & OPT_EOF_STRING1) && G.eof_str[0] == '\0')
428 G.eof_str = NULL;
429
430 if (opt & OPT_ZEROTERM)
431 IF_FEATURE_XARGS_SUPPORT_ZERO_TERM(read_args = process0_stdin);
432
433 argv += optind;
434 argc -= optind;
435 if (!argv[0]) {
436 /* default behavior is to echo all the filenames */
437 *--argv = (char*)"echo";
438 argc++;
439 }
440
441 /* -s NUM default. fileutils-4.4.2 uses 128k, but I heasitate
442 * to use such a big value - first need to change code to use
443 * growable buffer instead of fixed one.
444 */
445 n_max_chars = 32 * 1024;
446 /* Make smaller if system does not allow our default value.
447 * The Open Group Base Specifications Issue 6:
448 * "The xargs utility shall limit the command line length such that
449 * when the command line is invoked, the combined argument
450 * and environment lists (see the exec family of functions
451 * in the System Interfaces volume of IEEE Std 1003.1-2001)
452 * shall not exceed {ARG_MAX}-2048 bytes".
453 */
454 {
455 long arg_max = 0;
456#if defined _SC_ARG_MAX
457 arg_max = sysconf(_SC_ARG_MAX) - 2048;
458#elif defined ARG_MAX
459 arg_max = ARG_MAX - 2048;
460#endif
461 if (arg_max > 0 && n_max_chars > arg_max)
462 n_max_chars = arg_max;
463 }
464 if (opt & OPT_UPTO_SIZE) {
465 n_max_chars = xatou_range(max_chars, 1, INT_MAX);
466 }
467 /* Account for prepended fixed arguments */
468 {
469 size_t n_chars = 0;
470 for (i = 0; argv[i]; i++) {
471 n_chars += strlen(argv[i]) + 1;
472 }
473 n_max_chars -= n_chars;
474 }
475 /* Sanity check */
476 if (n_max_chars <= 0) {
477 bb_error_msg_and_die("can't fit single argument within argument list size limit");
478 }
479
480 buf = xzalloc(n_max_chars + 1);
481
482 n_max_arg = n_max_chars;
483 if (opt & OPT_UPTO_NUMBER) {
484 n_max_arg = xatou_range(max_args, 1, INT_MAX);
485 /* Not necessary, we use growable args[]: */
486 /* if (n_max_arg > n_max_chars) n_max_arg = n_max_chars */
487 }
488
489 /* Allocate pointers for execvp */
490 /* We can statically allocate (argc + n_max_arg + 1) elements
491 * and do not bother with resizing args[], but on 64-bit machines
492 * this results in args[] vector which is ~8 times bigger
493 * than n_max_chars! That is, with n_max_chars == 20k,
494 * args[] will take 160k (!), which will most likely be
495 * almost entirely unused.
496 */
497 /* See store_param() for matching 256-step growth logic */
498 G.args = xmalloc(sizeof(G.args[0]) * ((argc + 0xff) & ~0xff));
499
500 /* Store the command to be executed, part 1 */
501 for (i = 0; argv[i]; i++)
502 G.args[i] = argv[i];
503
504 while (1) {
505 char *rem;
506
507 G.idx = argc;
508 rem = read_args(n_max_chars, n_max_arg, buf);
509 store_param(NULL);
510
511 if (!G.args[argc]) {
512 if (*rem != '\0')
513 bb_error_msg_and_die("argument line too long");
514 if (opt & OPT_NO_EMPTY)
515 break;
516 }
517 opt |= OPT_NO_EMPTY;
518
519 if (opt & (OPT_INTERACTIVE | OPT_VERBOSE)) {
520 const char *fmt = " %s" + 1;
521 char **args = G.args;
522 for (i = 0; args[i]; i++) {
523 fprintf(stderr, fmt, args[i]);
524 fmt = " %s";
525 }
526 if (!(opt & OPT_INTERACTIVE))
527 bb_putchar_stderr('\n');
528 }
529
530 if (!(opt & OPT_INTERACTIVE) || xargs_ask_confirmation()) {
531 child_error = xargs_exec();
532 }
533
534 if (child_error > 0 && child_error != 123) {
535 break;
536 }
537
538 overlapping_strcpy(buf, rem);
539 } /* while */
540
541 if (ENABLE_FEATURE_CLEAN_UP) {
542 free(G.args);
543 free(buf);
544 }
545
546 return child_error;
547}
548
549
550#ifdef TEST
551
552const char *applet_name = "debug stuff usage";
553
554void bb_show_usage(void)
555{
556 fprintf(stderr, "Usage: %s [-p] [-r] [-t] -[x] [-n max_arg] [-s max_chars]\n",
557 applet_name);
558 exit(EXIT_FAILURE);
559}
560
561int main(int argc, char **argv)
562{
563 return xargs_main(argc, argv);
564}
565#endif /* TEST */
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