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 //config:config XARGS
18 //config: bool "xargs (7.2 kb)"
19 //config: default y
20 //config: help
21 //config: xargs is used to execute a specified command for
22 //config: every item from standard input.
23 //config:
24 //config:config FEATURE_XARGS_SUPPORT_CONFIRMATION
25 //config: bool "Enable -p: prompt and confirmation"
26 //config: default y
27 //config: depends on XARGS
28 //config: help
29 //config: Support -p: prompt the user whether to run each command
30 //config: line and read a line from the terminal.
31 //config:
32 //config:config FEATURE_XARGS_SUPPORT_QUOTES
33 //config: bool "Enable single and double quotes and backslash"
34 //config: default y
35 //config: depends on XARGS
36 //config: help
37 //config: Support quoting in the input.
38 //config:
39 //config:config FEATURE_XARGS_SUPPORT_TERMOPT
40 //config: bool "Enable -x: exit if -s or -n is exceeded"
41 //config: default y
42 //config: depends on XARGS
43 //config: help
44 //config: Support -x: exit if the command size (see the -s or -n option)
45 //config: is exceeded.
46 //config:
47 //config:config FEATURE_XARGS_SUPPORT_ZERO_TERM
48 //config: bool "Enable -0: NUL-terminated input"
49 //config: default y
50 //config: depends on XARGS
51 //config: help
52 //config: Support -0: input items are terminated by a NUL character
53 //config: instead of whitespace, and the quotes and backslash
54 //config: are not special.
55 //config:
56 //config:config FEATURE_XARGS_SUPPORT_REPL_STR
57 //config: bool "Enable -I STR: string to replace"
58 //config: default y
59 //config: depends on XARGS
60 //config: help
61 //config: Support -I STR and -i[STR] options.
62 //config:
63 //config:config FEATURE_XARGS_SUPPORT_PARALLEL
64 //config: bool "Enable -P N: processes to run in parallel"
65 //config: default y
66 //config: depends on XARGS
67 //config:
68 //config:config FEATURE_XARGS_SUPPORT_ARGS_FILE
69 //config: bool "Enable -a FILE: use FILE instead of stdin"
70 //config: default y
71 //config: depends on XARGS
72
73 //applet:IF_XARGS(APPLET_NOEXEC(xargs, xargs, BB_DIR_USR_BIN, BB_SUID_DROP, xargs))
74
75 //kbuild:lib-$(CONFIG_XARGS) += xargs.o
76
77 #include "libbb.h"
78 #include "common_bufsiz.h"
79
80 /* This is a NOEXEC applet. Be very careful! */
81
82
83 #if 0
84 # define dbg_msg(...) bb_error_msg(__VA_ARGS__)
85 #else
86 # define dbg_msg(...) ((void)0)
87 #endif
88
89 #ifdef TEST
90 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION
91 # define ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION 1
92 # endif
93 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_QUOTES
94 # define ENABLE_FEATURE_XARGS_SUPPORT_QUOTES 1
95 # endif
96 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT
97 # define ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT 1
98 # endif
99 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
100 # define ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM 1
101 # endif
102 #endif
103
104
105 struct globals {
106 char **args;
107 #if ENABLE_FEATURE_XARGS_SUPPORT_REPL_STR
108 char **argv;
109 const char *repl_str;
110 char eol_ch;
111 #endif
112 const char *eof_str;
113 int idx;
114 #if ENABLE_FEATURE_XARGS_SUPPORT_PARALLEL
115 int running_procs;
116 int max_procs;
117 #endif
118 smalluint xargs_exitcode;
119 #if ENABLE_FEATURE_XARGS_SUPPORT_QUOTES
120 #define NORM 0
121 #define QUOTE 1
122 #define BACKSLASH 2
123 #define SPACE 4
124 smalluint process_stdin__state;
125 char process_stdin__q;
126 #endif
127 } FIX_ALIASING;
128 #define G (*(struct globals*)bb_common_bufsiz1)
129 #define INIT_G() do { \
130 setup_common_bufsiz(); \
131 IF_FEATURE_XARGS_SUPPORT_REPL_STR(G.repl_str = "{}";) \
132 IF_FEATURE_XARGS_SUPPORT_REPL_STR(G.eol_ch = '\n';) \
133 /* Even zero values are set because we are NOEXEC applet */ \
134 G.eof_str = NULL; \
135 G.idx = 0; \
136 IF_FEATURE_XARGS_SUPPORT_PARALLEL(G.running_procs = 0;) \
137 IF_FEATURE_XARGS_SUPPORT_PARALLEL(G.max_procs = 1;) \
138 G.xargs_exitcode = 0; \
139 IF_FEATURE_XARGS_SUPPORT_QUOTES(G.process_stdin__state = NORM;) \
140 IF_FEATURE_XARGS_SUPPORT_QUOTES(G.process_stdin__q = '\0';) \
141 } while (0)
142
143
144 /*
145 * Returns 0 if xargs should continue (but may set G.xargs_exitcode to 123).
146 * Else sets G.xargs_exitcode to error code and returns nonzero.
147 *
148 * If G.max_procs == 0, performs final waitpid() loop for all children.
149 */
xargs_exec(void)150 static int xargs_exec(void)
151 {
152 int status;
153
154 #if !ENABLE_FEATURE_XARGS_SUPPORT_PARALLEL
155 status = spawn_and_wait(G.args);
156 #else
157 if (G.max_procs == 1) {
158 status = spawn_and_wait(G.args);
159 } else {
160 pid_t pid;
161 int wstat;
162 again:
163 if (G.running_procs >= G.max_procs)
164 pid = safe_waitpid(-1, &wstat, 0);
165 else
166 pid = wait_any_nohang(&wstat);
167 if (pid > 0) {
168 /* We may have children we don't know about:
169 * sh -c 'sleep 1 & exec xargs ...'
170 * Do not make G.running_procs go negative.
171 */
172 if (G.running_procs != 0)
173 G.running_procs--;
174 status = WIFSIGNALED(wstat)
175 ? 0x180 + WTERMSIG(wstat)
176 : WEXITSTATUS(wstat);
177 if (status > 0 && status < 255) {
178 /* See below why 123 does not abort */
179 G.xargs_exitcode = 123;
180 status = 0;
181 }
182 if (status == 0)
183 goto again; /* maybe we have more children? */
184 /* else: "bad" status, will bail out */
185 } else if (G.max_procs != 0) {
186 /* Not in final waitpid() loop,
187 * and G.running_procs < G.max_procs: start more procs
188 */
189 status = spawn(G.args);
190 /* here "status" actually holds pid, or -1 */
191 if (status > 0) {
192 G.running_procs++;
193 status = 0;
194 }
195 /* else: status == -1 (failed to fork or exec) */
196 } else {
197 /* final waitpid() loop: must be ECHILD "no more children" */
198 status = 0;
199 }
200 }
201 #endif
202 /* Manpage:
203 * """xargs exits with the following status:
204 * 0 if it succeeds
205 * 123 if any invocation of the command exited with status 1-125
206 * 124 if the command exited with status 255
207 * ("""If any invocation of the command exits with a status of 255,
208 * xargs will stop immediately without reading any further input.
209 * An error message is issued on stderr when this happens.""")
210 * 125 if the command is killed by a signal
211 * 126 if the command cannot be run
212 * 127 if the command is not found
213 * 1 if some other error occurred."""
214 */
215 if (status < 0) {
216 bb_simple_perror_msg(G.args[0]);
217 status = (errno == ENOENT) ? 127 : 126;
218 }
219 else if (status >= 0x180) {
220 bb_error_msg("'%s' terminated by signal %u",
221 G.args[0], status - 0x180);
222 status = 125;
223 }
224 else if (status != 0) {
225 if (status == 255) {
226 bb_error_msg("%s: exited with status 255; aborting", G.args[0]);
227 status = 124;
228 goto ret;
229 }
230 /* "123 if any invocation of the command exited with status 1-125"
231 * This implies that nonzero exit code is remembered,
232 * but does not cause xargs to stop: we return 0.
233 */
234 G.xargs_exitcode = 123;
235 status = 0;
236 }
237 ret:
238 if (status != 0)
239 G.xargs_exitcode = status;
240 return status;
241 }
242
243 /* In POSIX/C locale isspace is only these chars: "\t\n\v\f\r" and space.
244 * "\t\n\v\f\r" happen to have ASCII codes 9,10,11,12,13.
245 */
246 #define ISSPACE(a) ({ unsigned char xargs__isspace = (a) - 9; xargs__isspace == (' ' - 9) || xargs__isspace <= (13 - 9); })
247
store_param(char * s)248 static void store_param(char *s)
249 {
250 /* Grow by 256 elements at once */
251 if (!(G.idx & 0xff)) { /* G.idx == N*256? */
252 /* Enlarge, make G.args[(N+1)*256 - 1] last valid idx */
253 G.args = xrealloc(G.args, sizeof(G.args[0]) * (G.idx + 0x100));
254 }
255 G.args[G.idx++] = s;
256 }
257
258 /* process[0]_stdin:
259 * Read characters into buf[n_max_chars+1], and when parameter delimiter
260 * is seen, store the address of a new parameter to args[].
261 * If reading discovers that last chars do not form the complete
262 * parameter, the pointer to the first such "tail character" is returned.
263 * (buf has extra byte at the end to accommodate terminating NUL
264 * of "tail characters" string).
265 * Otherwise, the returned pointer points to NUL byte.
266 * On entry, buf[] may contain some "seed chars" which are to become
267 * the beginning of the first parameter.
268 */
269
270 #if ENABLE_FEATURE_XARGS_SUPPORT_QUOTES
process_stdin(int n_max_chars,int n_max_arg,char * buf)271 static char* FAST_FUNC process_stdin(int n_max_chars, int n_max_arg, char *buf)
272 {
273 #define q G.process_stdin__q
274 #define state G.process_stdin__state
275 char *s = buf; /* start of the word */
276 char *p = s + strlen(buf); /* end of the word */
277
278 buf += n_max_chars; /* past buffer's end */
279
280 /* "goto ret" is used instead of "break" to make control flow
281 * more obvious: */
282
283 while (1) {
284 int c = getchar();
285 if (c == EOF) {
286 if (p != s)
287 goto close_word;
288 goto ret;
289 }
290 if (state == BACKSLASH) {
291 state = NORM;
292 goto set;
293 }
294 if (state == QUOTE) {
295 if (c != q)
296 goto set;
297 q = '\0';
298 state = NORM;
299 } else { /* if (state == NORM) */
300 if (ISSPACE(c)) {
301 if (p != s) {
302 close_word:
303 state = SPACE;
304 c = '\0';
305 goto set;
306 }
307 } else {
308 if (c == '\\') {
309 state = BACKSLASH;
310 } else if (c == '\'' || c == '"') {
311 q = c;
312 state = QUOTE;
313 } else {
314 set:
315 *p++ = c;
316 }
317 }
318 }
319 if (state == SPACE) { /* word's delimiter or EOF detected */
320 state = NORM;
321 if (q) {
322 bb_error_msg_and_die("unmatched %s quote",
323 q == '\'' ? "single" : "double");
324 }
325 /* A full word is loaded */
326 if (G.eof_str) {
327 if (strcmp(s, G.eof_str) == 0) {
328 while (getchar() != EOF)
329 continue;
330 p = s;
331 goto ret;
332 }
333 }
334 store_param(s);
335 dbg_msg("args[]:'%s'", s);
336 s = p;
337 n_max_arg--;
338 if (n_max_arg == 0) {
339 goto ret;
340 }
341 }
342 if (p == buf) {
343 goto ret;
344 }
345 }
346 ret:
347 *p = '\0';
348 /* store_param(NULL) - caller will do it */
349 dbg_msg("return:'%s'", s);
350 return s;
351 #undef q
352 #undef state
353 }
354 #else
355 /* The variant does not support single quotes, double quotes or backslash */
process_stdin(int n_max_chars,int n_max_arg,char * buf)356 static char* FAST_FUNC process_stdin(int n_max_chars, int n_max_arg, char *buf)
357 {
358 char *s = buf; /* start of the word */
359 char *p = s + strlen(buf); /* end of the word */
360
361 buf += n_max_chars; /* past buffer's end */
362
363 while (1) {
364 int c = getchar();
365 if (c == EOF) {
366 if (p == s)
367 goto ret;
368 }
369 if (c == EOF || ISSPACE(c)) {
370 if (p == s)
371 continue;
372 c = EOF;
373 }
374 *p++ = (c == EOF ? '\0' : c);
375 if (c == EOF) { /* word's delimiter or EOF detected */
376 /* A full word is loaded */
377 if (G.eof_str) {
378 if (strcmp(s, G.eof_str) == 0) {
379 while (getchar() != EOF)
380 continue;
381 p = s;
382 goto ret;
383 }
384 }
385 store_param(s);
386 dbg_msg("args[]:'%s'", s);
387 s = p;
388 n_max_arg--;
389 if (n_max_arg == 0) {
390 goto ret;
391 }
392 }
393 if (p == buf) {
394 goto ret;
395 }
396 }
397 ret:
398 *p = '\0';
399 /* store_param(NULL) - caller will do it */
400 dbg_msg("return:'%s'", s);
401 return s;
402 }
403 #endif /* FEATURE_XARGS_SUPPORT_QUOTES */
404
405 #if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
process0_stdin(int n_max_chars,int n_max_arg,char * buf)406 static char* FAST_FUNC process0_stdin(int n_max_chars, int n_max_arg, char *buf)
407 {
408 char *s = buf; /* start of the word */
409 char *p = s + strlen(buf); /* end of the word */
410
411 buf += n_max_chars; /* past buffer's end */
412
413 while (1) {
414 int c = getchar();
415 if (c == EOF) {
416 if (p == s)
417 goto ret;
418 c = '\0';
419 }
420 *p++ = c;
421 if (c == '\0') { /* NUL or EOF detected */
422 /* A full word is loaded */
423 store_param(s);
424 dbg_msg("args[]:'%s'", s);
425 s = p;
426 n_max_arg--;
427 if (n_max_arg == 0) {
428 goto ret;
429 }
430 }
431 if (p == buf) {
432 goto ret;
433 }
434 }
435 ret:
436 *p = '\0';
437 /* store_param(NULL) - caller will do it */
438 dbg_msg("return:'%s'", s);
439 return s;
440 }
441 #endif /* FEATURE_XARGS_SUPPORT_ZERO_TERM */
442
443 #if ENABLE_FEATURE_XARGS_SUPPORT_REPL_STR
444 /*
445 * Used if -I<repl> was specified.
446 * In this mode, words aren't appended to PROG ARGS.
447 * Instead, entire input line is read, then <repl> string
448 * in every PROG and ARG is replaced with the line:
449 * echo -e "ho ho\nhi" | xargs -I_ cmd __ _
450 * results in "cmd 'ho hoho ho' 'ho ho'"; "cmd 'hihi' 'hi'".
451 * -n MAX_ARGS seems to be ignored.
452 * Tested with GNU findutils 4.5.10.
453 */
454 //FIXME: n_max_chars is not handled the same way as in GNU findutils.
455 //FIXME: quoting is not implemented.
process_stdin_with_replace(int n_max_chars,int n_max_arg UNUSED_PARAM,char * buf)456 static char* FAST_FUNC process_stdin_with_replace(int n_max_chars, int n_max_arg UNUSED_PARAM, char *buf)
457 {
458 int i;
459 char *end, *p;
460
461 /* Free strings from last invocation, if any */
462 for (i = 0; G.args && G.args[i]; i++)
463 if (G.args[i] != G.argv[i])
464 free(G.args[i]);
465
466 end = buf + n_max_chars;
467 p = buf;
468
469 while (1) {
470 int c = getchar();
471 if (p == buf) {
472 if (c == EOF)
473 goto ret; /* last line is empty, return "" */
474 if (c == G.eol_ch)
475 continue; /* empty line, ignore */
476 /* Skip leading whitespace of each line: try
477 * echo -e ' \t\v1 2 3 ' | xargs -I% echo '[%]'
478 */
479 if (ISSPACE(c))
480 continue;
481 }
482 if (c == EOF || c == G.eol_ch) {
483 c = '\0';
484 }
485 *p++ = c;
486 if (c == '\0') { /* EOL or EOF detected */
487 i = 0;
488 while (G.argv[i]) {
489 char *arg = G.argv[i];
490 int count = count_strstr(arg, G.repl_str);
491 if (count != 0)
492 arg = xmalloc_substitute_string(arg, count, G.repl_str, buf);
493 store_param(arg);
494 dbg_msg("args[]:'%s'", arg);
495 i++;
496 }
497 p = buf;
498 goto ret;
499 }
500 if (p == end) {
501 goto ret;
502 }
503 }
504 ret:
505 *p = '\0';
506 /* store_param(NULL) - caller will do it */
507 dbg_msg("return:'%s'", buf);
508 return buf;
509 }
510 #endif
511
512 #if ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION
513 /* Prompt the user for a response, and
514 * if user responds affirmatively, return true;
515 * otherwise, return false. Uses "/dev/tty", not stdin.
516 */
xargs_ask_confirmation(void)517 static int xargs_ask_confirmation(void)
518 {
519 FILE *tty_stream;
520 int r;
521
522 tty_stream = xfopen_for_read(CURRENT_TTY);
523
524 fputs(" ?...", stderr);
525 r = bb_ask_y_confirmation_FILE(tty_stream);
526
527 fclose(tty_stream);
528
529 return r;
530 }
531 #else
532 # define xargs_ask_confirmation() 1
533 #endif
534
535 //usage:#define xargs_trivial_usage
536 //usage: "[OPTIONS] [PROG ARGS]"
537 //usage:#define xargs_full_usage "\n\n"
538 //usage: "Run PROG on every item given by stdin\n"
539 //usage: IF_FEATURE_XARGS_SUPPORT_ZERO_TERM(
540 //usage: "\n -0 NUL terminated input"
541 //usage: )
542 //usage: IF_FEATURE_XARGS_SUPPORT_ARGS_FILE(
543 //usage: "\n -a FILE Read from FILE instead of stdin"
544 //usage: )
545 //usage: "\n -r Don't run command if input is empty"
546 //usage: "\n -t Print the command on stderr before execution"
547 //usage: IF_FEATURE_XARGS_SUPPORT_CONFIRMATION(
548 //usage: "\n -p Ask user whether to run each command"
549 //usage: )
550 //usage: "\n -E STR,-e[STR] STR stops input processing"
551 //usage: IF_FEATURE_XARGS_SUPPORT_REPL_STR(
552 //usage: "\n -I STR Replace STR within PROG ARGS with input line"
553 //usage: )
554 //usage: "\n -n N Pass no more than N args to PROG"
555 //usage: "\n -s N Pass command line of no more than N bytes"
556 //usage: IF_FEATURE_XARGS_SUPPORT_PARALLEL(
557 //usage: "\n -P N Run up to N PROGs in parallel"
558 //usage: )
559 //usage: IF_FEATURE_XARGS_SUPPORT_TERMOPT(
560 //usage: "\n -x Exit if size is exceeded"
561 //usage: )
562 //usage:#define xargs_example_usage
563 //usage: "$ ls | xargs gzip\n"
564 //usage: "$ find . -name '*.c' -print | xargs rm\n"
565
566 /* Correct regardless of combination of CONFIG_xxx */
567 enum {
568 OPTBIT_VERBOSE = 0,
569 OPTBIT_NO_EMPTY,
570 OPTBIT_UPTO_NUMBER,
571 OPTBIT_UPTO_SIZE,
572 OPTBIT_EOF_STRING,
573 OPTBIT_EOF_STRING1,
574 IF_FEATURE_XARGS_SUPPORT_CONFIRMATION(OPTBIT_INTERACTIVE,)
575 IF_FEATURE_XARGS_SUPPORT_TERMOPT( OPTBIT_TERMINATE ,)
576 IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( OPTBIT_ZEROTERM ,)
577 IF_FEATURE_XARGS_SUPPORT_REPL_STR( OPTBIT_REPLSTR ,)
578 IF_FEATURE_XARGS_SUPPORT_REPL_STR( OPTBIT_REPLSTR1 ,)
579
580 OPT_VERBOSE = 1 << OPTBIT_VERBOSE ,
581 OPT_NO_EMPTY = 1 << OPTBIT_NO_EMPTY ,
582 OPT_UPTO_NUMBER = 1 << OPTBIT_UPTO_NUMBER,
583 OPT_UPTO_SIZE = 1 << OPTBIT_UPTO_SIZE ,
584 OPT_EOF_STRING = 1 << OPTBIT_EOF_STRING , /* GNU: -e[<param>] */
585 OPT_EOF_STRING1 = 1 << OPTBIT_EOF_STRING1, /* SUS: -E<param> */
586 OPT_INTERACTIVE = IF_FEATURE_XARGS_SUPPORT_CONFIRMATION((1 << OPTBIT_INTERACTIVE)) + 0,
587 OPT_TERMINATE = IF_FEATURE_XARGS_SUPPORT_TERMOPT( (1 << OPTBIT_TERMINATE )) + 0,
588 OPT_ZEROTERM = IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( (1 << OPTBIT_ZEROTERM )) + 0,
589 OPT_REPLSTR = IF_FEATURE_XARGS_SUPPORT_REPL_STR( (1 << OPTBIT_REPLSTR )) + 0,
590 OPT_REPLSTR1 = IF_FEATURE_XARGS_SUPPORT_REPL_STR( (1 << OPTBIT_REPLSTR1 )) + 0,
591 };
592 #define OPTION_STR "+trn:s:e::E:" \
593 IF_FEATURE_XARGS_SUPPORT_CONFIRMATION("p") \
594 IF_FEATURE_XARGS_SUPPORT_TERMOPT( "x") \
595 IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( "0") \
596 IF_FEATURE_XARGS_SUPPORT_REPL_STR( "I:i::") \
597 IF_FEATURE_XARGS_SUPPORT_PARALLEL( "P:+") \
598 IF_FEATURE_XARGS_SUPPORT_ARGS_FILE( "a:")
599
600 int xargs_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
xargs_main(int argc UNUSED_PARAM,char ** argv)601 int xargs_main(int argc UNUSED_PARAM, char **argv)
602 {
603 int initial_idx;
604 int i;
605 char *max_args;
606 char *max_chars;
607 char *buf;
608 unsigned opt;
609 int n_max_chars;
610 int n_max_arg;
611 #if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM \
612 || ENABLE_FEATURE_XARGS_SUPPORT_REPL_STR
613 char* FAST_FUNC (*read_args)(int, int, char*) = process_stdin;
614 #else
615 #define read_args process_stdin
616 #endif
617 IF_FEATURE_XARGS_SUPPORT_ARGS_FILE(char *opt_a = NULL;)
618
619 INIT_G();
620
621 opt = getopt32long(argv, OPTION_STR,
622 "no-run-if-empty\0" No_argument "r",
623 &max_args, &max_chars, &G.eof_str, &G.eof_str
624 IF_FEATURE_XARGS_SUPPORT_REPL_STR(, &G.repl_str, &G.repl_str)
625 IF_FEATURE_XARGS_SUPPORT_PARALLEL(, &G.max_procs)
626 IF_FEATURE_XARGS_SUPPORT_ARGS_FILE(, &opt_a)
627 );
628
629 #if ENABLE_FEATURE_XARGS_SUPPORT_PARALLEL
630 if (G.max_procs <= 0) /* -P0 means "run lots of them" */
631 G.max_procs = 100; /* let's not go crazy high */
632 #endif
633
634 #if ENABLE_FEATURE_XARGS_SUPPORT_ARGS_FILE
635 if (opt_a)
636 xmove_fd(xopen(opt_a, O_RDONLY), 0);
637 #endif
638
639 /* -E ""? You may wonder why not just omit -E?
640 * This is used for portability:
641 * old xargs was using "_" as default for -E / -e */
642 if ((opt & OPT_EOF_STRING1) && G.eof_str[0] == '\0')
643 G.eof_str = NULL;
644
645 if (opt & OPT_ZEROTERM) {
646 IF_FEATURE_XARGS_SUPPORT_ZERO_TERM(read_args = process0_stdin;)
647 IF_FEATURE_XARGS_SUPPORT_REPL_STR(G.eol_ch = '\0';)
648 }
649
650 argv += optind;
651 //argc -= optind;
652 if (!argv[0]) {
653 /* default behavior is to echo all the filenames */
654 *--argv = (char*)"echo";
655 //argc++;
656 }
657
658 /*
659 * The Open Group Base Specifications Issue 6:
660 * "The xargs utility shall limit the command line length such that
661 * when the command line is invoked, the combined argument
662 * and environment lists (see the exec family of functions
663 * in the System Interfaces volume of IEEE Std 1003.1-2001)
664 * shall not exceed {ARG_MAX}-2048 bytes".
665 */
666 n_max_chars = bb_arg_max();
667 if (n_max_chars > 32 * 1024)
668 n_max_chars = 32 * 1024;
669 /*
670 * POSIX suggests substracting 2048 bytes from sysconf(_SC_ARG_MAX)
671 * so that the process may safely modify its environment.
672 */
673 n_max_chars -= 2048;
674
675 if (opt & OPT_UPTO_SIZE) {
676 n_max_chars = xatou_range(max_chars, 1, INT_MAX);
677 }
678 /* Account for prepended fixed arguments */
679 {
680 size_t n_chars = 0;
681 for (i = 0; argv[i]; i++) {
682 n_chars += strlen(argv[i]) + 1;
683 }
684 n_max_chars -= n_chars;
685 }
686 /* Sanity check */
687 if (n_max_chars <= 0) {
688 bb_simple_error_msg_and_die("can't fit single argument within argument list size limit");
689 }
690
691 buf = xzalloc(n_max_chars + 1);
692
693 n_max_arg = n_max_chars;
694 if (opt & OPT_UPTO_NUMBER) {
695 n_max_arg = xatou_range(max_args, 1, INT_MAX);
696 /* Not necessary, we use growable args[]: */
697 /* if (n_max_arg > n_max_chars) n_max_arg = n_max_chars */
698 }
699
700 #if ENABLE_FEATURE_XARGS_SUPPORT_REPL_STR
701 if (opt & (OPT_REPLSTR | OPT_REPLSTR1)) {
702 /*
703 * -I<str>:
704 * Unmodified args are kept in G.argv[i],
705 * G.args[i] receives malloced G.argv[i] with <str> replaced
706 * with input line. Setting this up:
707 */
708 G.args = NULL;
709 G.argv = argv;
710 read_args = process_stdin_with_replace;
711 /* Make -I imply -r. GNU findutils seems to do the same: */
712 /* (otherwise "echo -n | xargs -I% echo %" would SEGV) */
713 opt |= OPT_NO_EMPTY;
714 } else
715 #endif
716 {
717 /* Store the command to be executed, part 1.
718 * We can statically allocate (argc + n_max_arg + 1) elements
719 * and do not bother with resizing args[], but on 64-bit machines
720 * this results in args[] vector which is ~8 times bigger
721 * than n_max_chars! That is, with n_max_chars == 20k,
722 * args[] will take 160k (!), which will most likely be
723 * almost entirely unused.
724 */
725 for (i = 0; argv[i]; i++)
726 store_param(argv[i]);
727 }
728
729 initial_idx = G.idx;
730 while (1) {
731 char *rem;
732
733 G.idx = initial_idx;
734 rem = read_args(n_max_chars, n_max_arg, buf);
735 store_param(NULL);
736
737 if (!G.args[initial_idx]) { /* not even one ARG was added? */
738 if (*rem != '\0')
739 bb_simple_error_msg_and_die("argument line too long");
740 if (opt & OPT_NO_EMPTY)
741 break;
742 }
743 opt |= OPT_NO_EMPTY;
744
745 if (opt & (OPT_INTERACTIVE | OPT_VERBOSE)) {
746 const char *fmt = " %s" + 1;
747 char **args = G.args;
748 for (i = 0; args[i]; i++) {
749 fprintf(stderr, fmt, args[i]);
750 fmt = " %s";
751 }
752 if (!(opt & OPT_INTERACTIVE))
753 bb_putchar_stderr('\n');
754 }
755
756 if (!(opt & OPT_INTERACTIVE) || xargs_ask_confirmation()) {
757 if (xargs_exec() != 0)
758 break; /* G.xargs_exitcode is set by xargs_exec() */
759 }
760
761 overlapping_strcpy(buf, rem);
762 } /* while */
763
764 if (ENABLE_FEATURE_CLEAN_UP) {
765 free(G.args);
766 free(buf);
767 }
768
769 #if ENABLE_FEATURE_XARGS_SUPPORT_PARALLEL
770 G.max_procs = 0;
771 xargs_exec(); /* final waitpid() loop */
772 #endif
773
774 return G.xargs_exitcode;
775 }
776
777
778 #ifdef TEST
779
780 const char *applet_name = "debug stuff usage";
781
bb_show_usage(void)782 void bb_show_usage(void)
783 {
784 fprintf(stderr, "Usage: %s [-p] [-r] [-t] -[x] [-n max_arg] [-s max_chars]\n",
785 applet_name);
786 exit(EXIT_FAILURE);
787 }
788
main(int argc,char ** argv)789 int main(int argc, char **argv)
790 {
791 return xargs_main(argc, argv);
792 }
793 #endif /* TEST */
794