1 /* vi: set sw=4 ts=4: */
3 * Mini xargs implementation for busybox
5 * (C) 2002,2003 by Vladimir Oleynik <dzo@simtreas.ru>
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>.
12 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
14 * xargs is described in the Single Unix Specification v3 at
15 * http://www.opengroup.org/onlinepubs/007904975/utilities/xargs.html
18 //applet:IF_XARGS(APPLET_NOEXEC(xargs, xargs, _BB_DIR_USR_BIN, _BB_SUID_DROP, xargs))
20 //kbuild:lib-$(CONFIG_XARGS) += xargs.o
23 //config: bool "xargs"
26 //config: xargs is used to execute a specified command for
27 //config: every item from standard input.
29 //config:config FEATURE_XARGS_SUPPORT_CONFIRMATION
30 //config: bool "Enable -p: prompt and confirmation"
32 //config: depends on XARGS
34 //config: Support -p: prompt the user whether to run each command
35 //config: line and read a line from the terminal.
37 //config:config FEATURE_XARGS_SUPPORT_QUOTES
38 //config: bool "Enable single and double quotes and backslash"
40 //config: depends on XARGS
42 //config: Support quoting in the input.
44 //config:config FEATURE_XARGS_SUPPORT_TERMOPT
45 //config: bool "Enable -x: exit if -s or -n is exceeded"
47 //config: depends on XARGS
49 //config: Support -x: exit if the command size (see the -s or -n option)
50 //config: is exceeded.
52 //config:config FEATURE_XARGS_SUPPORT_ZERO_TERM
53 //config: bool "Enable -0: NUL-terminated input"
55 //config: depends on XARGS
57 //config: Support -0: input items are terminated by a NUL character
58 //config: instead of whitespace, and the quotes and backslash
59 //config: are not special.
63 /* This is a NOEXEC applet. Be very careful! */
66 //#define dbg_msg(...) bb_error_msg(__VA_ARGS__)
67 #define dbg_msg(...) ((void)0)
71 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION
72 # define ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION 1
74 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_QUOTES
75 # define ENABLE_FEATURE_XARGS_SUPPORT_QUOTES 1
77 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT
78 # define ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT 1
80 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
81 # define ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM 1
91 #define G (*(struct globals*)&bb_common_bufsiz1)
92 #define INIT_G() do { } while (0)
96 * This function has special algorithm.
97 * Don't use fork and include to main!
99 static int xargs_exec(void)
103 status = spawn_and_wait(G.args);
105 bb_simple_perror_msg(G.args[0]);
106 return errno == ENOENT ? 127 : 126;
109 bb_error_msg("%s: exited with status 255; aborting", G.args[0]);
112 if (status >= 0x180) {
113 bb_error_msg("%s: terminated by signal %d",
114 G.args[0], status - 0x180);
122 /* In POSIX/C locale isspace is only these chars: "\t\n\v\f\r" and space.
123 * "\t\n\v\f\r" happen to have ASCII codes 9,10,11,12,13.
125 #define ISSPACE(a) ({ unsigned char xargs__isspace = (a) - 9; xargs__isspace == (' ' - 9) || xargs__isspace <= (13 - 9); })
127 static void store_param(char *s)
129 /* Grow by 256 elements at once */
130 if (!(G.idx & 0xff)) { /* G.idx == N*256 */
131 /* Enlarge, make G.args[(N+1)*256 - 1] last valid idx */
132 G.args = xrealloc(G.args, sizeof(G.args[0]) * (G.idx + 0x100));
138 * Read characters into buf[n_max_chars+1], and when parameter delimiter
139 * is seen, store the address of a new parameter to args[].
140 * If reading discovers that last chars do not form the complete
141 * parameter, the pointer to the first such "tail character" is returned.
142 * (buf has extra byte at the end to accomodate terminating NUL
143 * of "tail characters" string).
144 * Otherwise, the returned pointer points to NUL byte.
145 * On entry, buf[] may contain some "seed chars" which are to become
146 * the beginning of the first parameter.
149 #if ENABLE_FEATURE_XARGS_SUPPORT_QUOTES
150 static char* FAST_FUNC process_stdin(int n_max_chars, int n_max_arg, char *buf)
156 char q = '\0'; /* quote char */
158 char *s = buf; /* start of the word */
159 char *p = s + strlen(buf); /* end of the word */
161 buf += n_max_chars; /* past buffer's end */
163 /* "goto ret" is used instead of "break" to make control flow
173 if (state == BACKSLASH) {
177 if (state == QUOTE) {
182 } else { /* if (state == NORM) */
193 } else if (c == '\'' || c == '"') {
202 if (state == SPACE) { /* word's delimiter or EOF detected */
204 bb_error_msg_and_die("unmatched %s quote",
205 q == '\'' ? "single" : "double");
207 /* A full word is loaded */
209 if (strcmp(s, G.eof_str) == 0) {
210 while (getchar() != EOF)
217 dbg_msg("args[]:'%s'", s);
220 if (n_max_arg == 0) {
231 /* store_param(NULL) - caller will do it */
232 dbg_msg("return:'%s'", s);
236 /* The variant does not support single quotes, double quotes or backslash */
237 static char* FAST_FUNC process_stdin(int n_max_chars, int n_max_arg, char *buf)
239 char *s = buf; /* start of the word */
240 char *p = s + strlen(buf); /* end of the word */
242 buf += n_max_chars; /* past buffer's end */
250 if (c == EOF || ISSPACE(c)) {
255 *p++ = (c == EOF ? '\0' : c);
256 if (c == EOF) { /* word's delimiter or EOF detected */
257 /* A full word is loaded */
259 if (strcmp(s, G.eof_str) == 0) {
260 while (getchar() != EOF)
267 dbg_msg("args[]:'%s'", s);
270 if (n_max_arg == 0) {
280 /* store_param(NULL) - caller will do it */
281 dbg_msg("return:'%s'", s);
284 #endif /* FEATURE_XARGS_SUPPORT_QUOTES */
286 #if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
287 static char* FAST_FUNC process0_stdin(int n_max_chars, int n_max_arg, char *buf)
289 char *s = buf; /* start of the word */
290 char *p = s + strlen(buf); /* end of the word */
292 buf += n_max_chars; /* past buffer's end */
302 if (c == '\0') { /* word's delimiter or EOF detected */
303 /* A full word is loaded */
305 dbg_msg("args[]:'%s'", s);
308 if (n_max_arg == 0) {
318 /* store_param(NULL) - caller will do it */
319 dbg_msg("return:'%s'", s);
322 #endif /* FEATURE_XARGS_SUPPORT_ZERO_TERM */
324 #if ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION
325 /* Prompt the user for a response, and
326 if the user responds affirmatively, return true;
327 otherwise, return false. Uses "/dev/tty", not stdin. */
328 static int xargs_ask_confirmation(void)
333 tty_stream = xfopen_for_read(CURRENT_TTY);
334 fputs(" ?...", stderr);
336 c = savec = getc(tty_stream);
337 while (c != EOF && c != '\n')
338 c = getc(tty_stream);
340 return (savec == 'y' || savec == 'Y');
343 # define xargs_ask_confirmation() 1
346 //usage:#define xargs_trivial_usage
347 //usage: "[OPTIONS] [PROG ARGS]"
348 //usage:#define xargs_full_usage "\n\n"
349 //usage: "Run PROG on every item given by stdin\n"
350 //usage: "\nOptions:"
351 //usage: IF_FEATURE_XARGS_SUPPORT_CONFIRMATION(
352 //usage: "\n -p Ask user whether to run each command"
354 //usage: "\n -r Don't run command if input is empty"
355 //usage: IF_FEATURE_XARGS_SUPPORT_ZERO_TERM(
356 //usage: "\n -0 Input is separated by NUL characters"
358 //usage: "\n -t Print the command on stderr before execution"
359 //usage: "\n -e[STR] STR stops input processing"
360 //usage: "\n -n N Pass no more than N args to PROG"
361 //usage: "\n -s N Pass command line of no more than N bytes"
362 //usage: IF_FEATURE_XARGS_SUPPORT_TERMOPT(
363 //usage: "\n -x Exit if size is exceeded"
365 //usage:#define xargs_example_usage
366 //usage: "$ ls | xargs gzip\n"
367 //usage: "$ find . -name '*.c' -print | xargs rm\n"
369 /* Correct regardless of combination of CONFIG_xxx */
377 IF_FEATURE_XARGS_SUPPORT_CONFIRMATION(OPTBIT_INTERACTIVE,)
378 IF_FEATURE_XARGS_SUPPORT_TERMOPT( OPTBIT_TERMINATE ,)
379 IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( OPTBIT_ZEROTERM ,)
381 OPT_VERBOSE = 1 << OPTBIT_VERBOSE ,
382 OPT_NO_EMPTY = 1 << OPTBIT_NO_EMPTY ,
383 OPT_UPTO_NUMBER = 1 << OPTBIT_UPTO_NUMBER,
384 OPT_UPTO_SIZE = 1 << OPTBIT_UPTO_SIZE ,
385 OPT_EOF_STRING = 1 << OPTBIT_EOF_STRING , /* GNU: -e[<param>] */
386 OPT_EOF_STRING1 = 1 << OPTBIT_EOF_STRING1, /* SUS: -E<param> */
387 OPT_INTERACTIVE = IF_FEATURE_XARGS_SUPPORT_CONFIRMATION((1 << OPTBIT_INTERACTIVE)) + 0,
388 OPT_TERMINATE = IF_FEATURE_XARGS_SUPPORT_TERMOPT( (1 << OPTBIT_TERMINATE )) + 0,
389 OPT_ZEROTERM = IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( (1 << OPTBIT_ZEROTERM )) + 0,
391 #define OPTION_STR "+trn:s:e::E:" \
392 IF_FEATURE_XARGS_SUPPORT_CONFIRMATION("p") \
393 IF_FEATURE_XARGS_SUPPORT_TERMOPT( "x") \
394 IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( "0")
396 int xargs_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
397 int xargs_main(int argc, char **argv)
407 #if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
408 char* FAST_FUNC (*read_args)(int, int, char*) = process_stdin;
410 #define read_args process_stdin
416 opt = getopt32(argv, OPTION_STR, &max_args, &max_chars, &G.eof_str, &G.eof_str);
418 /* -E ""? You may wonder why not just omit -E?
419 * This is used for portability:
420 * old xargs was using "_" as default for -E / -e */
421 if ((opt & OPT_EOF_STRING1) && G.eof_str[0] == '\0')
424 if (opt & OPT_ZEROTERM)
425 IF_FEATURE_XARGS_SUPPORT_ZERO_TERM(read_args = process0_stdin);
430 /* default behavior is to echo all the filenames */
431 *--argv = (char*)"echo";
435 /* -s NUM default. fileutils-4.4.2 uses 128k, but I heasitate
436 * to use such a big value - first need to change code to use
437 * growable buffer instead of fixed one.
439 n_max_chars = 32 * 1024;
440 /* Make smaller if system does not allow our default value.
441 * The Open Group Base Specifications Issue 6:
442 * "The xargs utility shall limit the command line length such that
443 * when the command line is invoked, the combined argument
444 * and environment lists (see the exec family of functions
445 * in the System Interfaces volume of IEEE Std 1003.1-2001)
446 * shall not exceed {ARG_MAX}-2048 bytes".
450 #if defined _SC_ARG_MAX
451 arg_max = sysconf(_SC_ARG_MAX) - 2048;
452 #elif defined ARG_MAX
453 arg_max = ARG_MAX - 2048;
455 if (arg_max > 0 && n_max_chars > arg_max)
456 n_max_chars = arg_max;
458 if (opt & OPT_UPTO_SIZE) {
459 n_max_chars = xatou_range(max_chars, 1, INT_MAX);
461 /* Account for prepended fixed arguments */
464 for (i = 0; argv[i]; i++) {
465 n_chars += strlen(argv[i]) + 1;
467 n_max_chars -= n_chars;
470 if (n_max_chars <= 0) {
471 bb_error_msg_and_die("can't fit single argument within argument list size limit");
474 buf = xzalloc(n_max_chars + 1);
476 n_max_arg = n_max_chars;
477 if (opt & OPT_UPTO_NUMBER) {
478 n_max_arg = xatou_range(max_args, 1, INT_MAX);
479 /* Not necessary, we use growable args[]: */
480 /* if (n_max_arg > n_max_chars) n_max_arg = n_max_chars */
483 /* Allocate pointers for execvp */
484 /* We can statically allocate (argc + n_max_arg + 1) elements
485 * and do not bother with resizing args[], but on 64-bit machines
486 * this results in args[] vector which is ~8 times bigger
487 * than n_max_chars! That is, with n_max_chars == 20k,
488 * args[] will take 160k (!), which will most likely be
489 * almost entirely unused.
491 /* See store_param() for matching 256-step growth logic */
492 G.args = xmalloc(sizeof(G.args[0]) * ((argc + 0xff) & ~0xff));
494 /* Store the command to be executed, part 1 */
495 for (i = 0; argv[i]; i++)
502 rem = read_args(n_max_chars, n_max_arg, buf);
507 bb_error_msg_and_die("argument line too long");
508 if (opt & OPT_NO_EMPTY)
513 if (opt & (OPT_INTERACTIVE | OPT_VERBOSE)) {
514 const char *fmt = " %s" + 1;
515 char **args = G.args;
516 for (i = 0; args[i]; i++) {
517 fprintf(stderr, fmt, args[i]);
520 if (!(opt & OPT_INTERACTIVE))
521 bb_putchar_stderr('\n');
524 if (!(opt & OPT_INTERACTIVE) || xargs_ask_confirmation()) {
525 child_error = xargs_exec();
528 if (child_error > 0 && child_error != 123) {
532 overlapping_strcpy(buf, rem);
535 if (ENABLE_FEATURE_CLEAN_UP) {
546 const char *applet_name = "debug stuff usage";
548 void bb_show_usage(void)
550 fprintf(stderr, "Usage: %s [-p] [-r] [-t] -[x] [-n max_arg] [-s max_chars]\n",
555 int main(int argc, char **argv)
557 return xargs_main(argc, argv);