busybox/findutils/xargs.c

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/*
* Mini xargs implementation for busybox
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* Options are supported: "-prtx -n max_arg -s max_chars -e[ouf_str]"
*
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* (C) 2002,2003 by Vladimir Oleynik <dzo@simtreas.ru>
*
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* Special thanks
* - Mark Whitley and Glenn McGrath for stimulus to rewrite :)
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* - Mike Rendell <michael@cs.mun.ca>
* and David MacKenzie <djm@gnu.ai.mit.edu>.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* xargs is described in the Single Unix Specification v3 at
* http://www.opengroup.org/onlinepubs/007904975/utilities/xargs.html
*
*/
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <getopt.h>
#include <errno.h>
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#include <fcntl.h>
#include <sys/types.h>
#include <sys/wait.h>
#include "busybox.h"
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/* COMPAT: SYSV version defaults size (and has a max value of) to 470.
We try to make it as large as possible. */
#if !defined(ARG_MAX) && defined(_SC_ARG_MAX)
#define ARG_MAX sysconf (_SC_ARG_MAX)
#endif
#ifndef ARG_MAX
#define ARG_MAX 470
#endif
#ifdef TEST
# ifndef CONFIG_FEATURE_XARGS_SUPPORT_CONFIRMATION
# define CONFIG_FEATURE_XARGS_SUPPORT_CONFIRMATION
# endif
# ifndef CONFIG_FEATURE_XARGS_SUPPORT_QUOTES
# define CONFIG_FEATURE_XARGS_SUPPORT_QUOTES
# endif
# ifndef CONFIG_FEATURE_XARGS_SUPPORT_TERMOPT
# define CONFIG_FEATURE_XARGS_SUPPORT_TERMOPT
# endif
# ifndef CONFIG_FEATURE_XARGS_SUPPORT_ZERO_TERM
# define CONFIG_FEATURE_XARGS_SUPPORT_ZERO_TERM
# endif
#endif
/*
This function have special algorithm.
Don`t use fork and include to main!
*/
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static int xargs_exec(char *const *args)
{
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pid_t p;
volatile int exec_errno = 0; /* shared vfork stack */
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if ((p = vfork()) >= 0) {
if (p == 0) {
/* vfork -- child */
execvp(args[0], args);
exec_errno = errno; /* set error to shared stack */
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_exit(1);
} else {
/* vfork -- parent */
int status;
while (wait(&status) == (pid_t) - 1)
if (errno != EINTR)
break;
if (exec_errno) {
errno = exec_errno;
bb_perror_msg("%s", args[0]);
return exec_errno == ENOENT ? 127 : 126;
} else {
if (WEXITSTATUS(status) == 255) {
bb_error_msg("%s: exited with status 255; aborting", args[0]);
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return 124;
}
if (WIFSTOPPED(status)) {
bb_error_msg("%s: stopped by signal %d",
args[0], WSTOPSIG(status));
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return 125;
}
if (WIFSIGNALED(status)) {
bb_error_msg("%s: terminated by signal %d",
args[0], WTERMSIG(status));
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return 125;
}
if (WEXITSTATUS(status) != 0)
return 123;
return 0;
}
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}
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} else {
bb_perror_msg_and_die("vfork");
}
}
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typedef struct xlist_s {
char *data;
size_t lenght;
struct xlist_s *link;
} xlist_t;
static int eof_stdin_detected;
#define ISBLANK(c) ((c) == ' ' || (c) == '\t')
#define ISSPACE(c) (ISBLANK (c) || (c) == '\n' || (c) == '\r' \
|| (c) == '\f' || (c) == '\v')
#ifdef CONFIG_FEATURE_XARGS_SUPPORT_QUOTES
static xlist_t *process_stdin(xlist_t * list_arg,
const char *eof_str, size_t mc, char *buf)
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{
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#define NORM 0
#define QUOTE 1
#define BACKSLASH 2
#define SPACE 4
char *s = NULL; /* start word */
char *p = NULL; /* pointer to end word */
char q = 0; /* quote char */
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char state = NORM;
char eof_str_detected = 0;
size_t line_l = 0; /* size loaded args line */
int c; /* current char */
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xlist_t *cur;
xlist_t *prev;
for (prev = cur = list_arg; cur; cur = cur->link) {
line_l += cur->lenght; /* previous allocated */
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if (prev != cur)
prev = prev->link;
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}
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while (!eof_stdin_detected) {
c = getchar();
if (c == EOF) {
eof_stdin_detected++;
if (s)
goto unexpected_eof;
break;
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}
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if (eof_str_detected)
continue;
if (state == BACKSLASH) {
state = NORM;
goto set;
} else if (state == QUOTE) {
if (c == q) {
q = 0;
state = NORM;
} else {
goto set;
}
} else { /* if(state == NORM) */
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if (ISSPACE(c)) {
if (s) {
unexpected_eof:
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state = SPACE;
c = 0;
goto set;
}
} else {
if (s == NULL)
s = p = buf;
if (c == '\\') {
state = BACKSLASH;
} else if (c == '\'' || c == '"') {
q = c;
state = QUOTE;
} else {
set:
if ((size_t)(p - buf) >= mc)
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bb_error_msg_and_die("argument line too long");
*p++ = c;
}
}
}
if (state == SPACE) { /* word's delimiter or EOF detected */
if (q) {
bb_error_msg_and_die("unmatched %s quote",
q == '\'' ? "single" : "double");
}
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/* word loaded */
if (eof_str) {
eof_str_detected = strcmp(s, eof_str) == 0;
}
if (!eof_str_detected) {
size_t lenght = (p - buf);
cur = xmalloc(sizeof(xlist_t) + lenght);
cur->data = memcpy(cur + 1, s, lenght);
cur->lenght = lenght;
cur->link = NULL;
if (prev == NULL) {
list_arg = cur;
} else {
prev->link = cur;
}
prev = cur;
line_l += lenght;
if (line_l > mc) {
/* stop memory usage :-) */
break;
}
}
s = NULL;
state = NORM;
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}
}
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return list_arg;
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}
#else
/* The variant does not support single quotes, double quotes or backslash */
static xlist_t *process_stdin(xlist_t * list_arg,
const char *eof_str, size_t mc, char *buf)
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{
int c; /* current char */
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int eof_str_detected = 0;
char *s = NULL; /* start word */
char *p = NULL; /* pointer to end word */
size_t line_l = 0; /* size loaded args line */
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xlist_t *cur;
xlist_t *prev;
for (prev = cur = list_arg; cur; cur = cur->link) {
line_l += cur->lenght; /* previous allocated */
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if (prev != cur)
prev = prev->link;
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}
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while (!eof_stdin_detected) {
c = getchar();
if (c == EOF) {
eof_stdin_detected++;
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}
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if (eof_str_detected)
continue;
if (c == EOF || ISSPACE(c)) {
if (s == NULL)
continue;
c = EOF;
}
if (s == NULL)
s = p = buf;
if ((p - buf) >= mc)
bb_error_msg_and_die("argument line too long");
*p++ = c == EOF ? 0 : c;
if (c == EOF) { /* word's delimiter or EOF detected */
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/* word loaded */
if (eof_str) {
eof_str_detected = strcmp(s, eof_str) == 0;
}
if (!eof_str_detected) {
size_t lenght = (p - buf);
cur = xmalloc(sizeof(xlist_t) + lenght);
cur->data = memcpy(cur + 1, s, lenght);
cur->lenght = lenght;
cur->link = NULL;
if (prev == NULL) {
list_arg = cur;
} else {
prev->link = cur;
}
prev = cur;
line_l += lenght;
if (line_l > mc) {
/* stop memory usage :-) */
break;
}
s = NULL;
}
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}
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}
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return list_arg;
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}
#endif /* CONFIG_FEATURE_XARGS_SUPPORT_QUOTES */
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#ifdef CONFIG_FEATURE_XARGS_SUPPORT_CONFIRMATION
/* Prompt the user for a response, and
if the user responds affirmatively, return true;
otherwise, return false. Used "/dev/tty", not stdin. */
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static int xargs_ask_confirmation(void)
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{
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static FILE *tty_stream;
int c, savec;
if (!tty_stream) {
tty_stream = fopen("/dev/tty", "r");
if (!tty_stream)
bb_perror_msg_and_die("/dev/tty");
/* pranoidal security by vodz */
fcntl(fileno(tty_stream), F_SETFD, FD_CLOEXEC);
}
fputs(" ?...", stderr);
fflush(stderr);
c = savec = getc(tty_stream);
while (c != EOF && c != '\n')
c = getc(tty_stream);
if (savec == 'y' || savec == 'Y')
return 1;
return 0;
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}
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# define OPT_INC_P 1
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#else
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# define OPT_INC_P 0
# define xargs_ask_confirmation() 1
#endif /* CONFIG_FEATURE_XARGS_SUPPORT_CONFIRMATION */
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#ifdef CONFIG_FEATURE_XARGS_SUPPORT_TERMOPT
# define OPT_INC_X 1
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#else
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# define OPT_INC_X 0
#endif
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#ifdef CONFIG_FEATURE_XARGS_SUPPORT_ZERO_TERM
static xlist_t *process0_stdin(xlist_t * list_arg, const char *eof_str ATTRIBUTE_UNUSED,
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size_t mc, char *buf)
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{
int c; /* current char */
char *s = NULL; /* start word */
char *p = NULL; /* pointer to end word */
size_t line_l = 0; /* size loaded args line */
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xlist_t *cur;
xlist_t *prev;
for (prev = cur = list_arg; cur; cur = cur->link) {
line_l += cur->lenght; /* previous allocated */
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if (prev != cur)
prev = prev->link;
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}
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while (!eof_stdin_detected) {
c = getchar();
if (c == EOF) {
eof_stdin_detected++;
if (s == NULL)
break;
c = 0;
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}
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if (s == NULL)
s = p = buf;
if ((size_t)(p - buf) >= mc)
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bb_error_msg_and_die("argument line too long");
*p++ = c;
if (c == 0) { /* word's delimiter or EOF detected */
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/* word loaded */
size_t lenght = (p - buf);
cur = xmalloc(sizeof(xlist_t) + lenght);
cur->data = memcpy(cur + 1, s, lenght);
cur->lenght = lenght;
cur->link = NULL;
if (prev == NULL) {
list_arg = cur;
} else {
prev->link = cur;
}
prev = cur;
line_l += lenght;
if (line_l > mc) {
/* stop memory usage :-) */
break;
}
s = NULL;
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}
}
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return list_arg;
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}
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# define READ_ARGS(l, e, nmc, mc) (*read_args)(l, e, nmc, mc)
# define OPT_INC_0 1 /* future use */
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#else
# define OPT_INC_0 0 /* future use */
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# define READ_ARGS(l, e, nmc, mc) process_stdin(l, e, nmc, mc)
#endif /* CONFIG_FEATURE_XARGS_SUPPORT_ZERO_TERM */
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#define OPT_VERBOSE (1<<0)
#define OPT_NO_EMPTY (1<<1)
#define OPT_UPTO_NUMBER (1<<2)
#define OPT_UPTO_SIZE (1<<3)
#define OPT_EOF_STRING (1<<4)
#ifdef CONFIG_FEATURE_XARGS_SUPPORT_CONFIRMATION
#define OPT_INTERACTIVE (1<<5)
#else
#define OPT_INTERACTIVE (0) /* require for algorithm &| */
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#endif
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#define OPT_TERMINATE (1<<(5+OPT_INC_P))
#define OPT_ZEROTERM (1<<(5+OPT_INC_P+OPT_INC_X))
/* next future
#define OPT_NEXT_OTHER (1<<(5+OPT_INC_P+OPT_INC_X+OPT_INC_0))
*/
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int xargs_main(int argc, char **argv)
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{
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char **args;
int i, a, n;
xlist_t *list = NULL;
xlist_t *cur;
int child_error = 0;
char *max_args, *max_chars;
int n_max_arg;
size_t n_chars = 0;
long orig_arg_max;
const char *eof_str = "_";
unsigned long opt;
size_t n_max_chars;
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#ifdef CONFIG_FEATURE_XARGS_SUPPORT_ZERO_TERM
xlist_t *(*read_args) (xlist_t *, const char *, size_t, char *) = process_stdin;
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#endif
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#ifdef CONFIG_FEATURE_XARGS_SUPPORT_CONFIRMATION
bb_opt_complementally = "pt";
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#endif
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opt = bb_getopt_ulflags(argc, argv, "+trn:s:e::"
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#ifdef CONFIG_FEATURE_XARGS_SUPPORT_CONFIRMATION
"p"
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#endif
#ifdef CONFIG_FEATURE_XARGS_SUPPORT_TERMOPT
"x"
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#endif
#ifdef CONFIG_FEATURE_XARGS_SUPPORT_ZERO_TERM
"0"
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#endif
,&max_args, &max_chars, &eof_str);
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a = argc - optind;
argv += optind;
if (a == 0) {
/* default behavior is to echo all the filenames */
*argv = "echo";
a++;
}
orig_arg_max = ARG_MAX;
if (orig_arg_max == -1)
orig_arg_max = LONG_MAX;
orig_arg_max -= 2048; /* POSIX.2 requires subtracting 2048. */
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if ((opt & OPT_UPTO_SIZE)) {
n_max_chars = bb_xgetularg10_bnd(max_chars, 1, orig_arg_max);
for (i = 0; i < a; i++) {
n_chars += strlen(*argv) + 1;
}
if (n_max_chars < n_chars) {
bb_error_msg_and_die("can not fit single argument within argument list size limit");
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}
n_max_chars -= n_chars;
} else {
/* Sanity check for systems with huge ARG_MAX defines (e.g., Suns which
have it at 1 meg). Things will work fine with a large ARG_MAX but it
will probably hurt the system more than it needs to; an array of this
size is allocated. */
if (orig_arg_max > 20 * 1024)
orig_arg_max = 20 * 1024;
n_max_chars = orig_arg_max;
}
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max_chars = xmalloc(n_max_chars);
if ((opt & OPT_UPTO_NUMBER)) {
n_max_arg = bb_xgetularg10_bnd(max_args, 1, INT_MAX);
} else {
n_max_arg = n_max_chars;
}
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#ifdef CONFIG_FEATURE_XARGS_SUPPORT_ZERO_TERM
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if (opt & OPT_ZEROTERM)
read_args = process0_stdin;
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#endif
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while ((list = READ_ARGS(list, eof_str, n_max_chars, max_chars)) != NULL ||
(opt & OPT_NO_EMPTY) == 0)
{
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opt |= OPT_NO_EMPTY;
n = 0;
n_chars = 0;
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#ifdef CONFIG_FEATURE_XARGS_SUPPORT_TERMOPT
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for (cur = list; cur;) {
n_chars += cur->lenght;
n++;
cur = cur->link;
if (n_chars > n_max_chars || (n == n_max_arg && cur)) {
if (opt & OPT_TERMINATE)
bb_error_msg_and_die("argument list too long");
break;
}
}
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#else
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for (cur = list; cur; cur = cur->link) {
n_chars += cur->lenght;
n++;
if (n_chars > n_max_chars || n == n_max_arg) {
break;
}
}
#endif /* CONFIG_FEATURE_XARGS_SUPPORT_TERMOPT */
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/* allocating pointers for execvp:
a*arg, n*arg from stdin, NULL */
args = xcalloc(n + a + 1, sizeof(char *));
/* Store the command to be executed
(taken from the command line) */
for (i = 0; i < a; i++)
args[i] = argv[i];
/* (taken from stdin) */
for (cur = list; n; cur = cur->link) {
args[i++] = cur->data;
n--;
}
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if ((opt & (OPT_INTERACTIVE | OPT_VERBOSE))) {
for (i = 0; args[i]; i++) {
if (i)
fputc(' ', stderr);
fputs(args[i], stderr);
}
if ((opt & OPT_INTERACTIVE) == 0)
fputc('\n', stderr);
}
if ((opt & OPT_INTERACTIVE) == 0 || xargs_ask_confirmation() != 0) {
child_error = xargs_exec(args);
}
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/* clean up */
for (i = a; args[i]; i++) {
cur = list;
list = list->link;
free(cur);
}
free(args);
if (child_error > 0 && child_error != 123) {
break;
}
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}
#ifdef CONFIG_FEATURE_CLEAN_UP
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free(max_chars);
#endif
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return child_error;
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}
#ifdef TEST
const char *bb_applet_name = "debug stuff usage";
void bb_show_usage(void)
{
fprintf(stderr, "Usage: %s [-p] [-r] [-t] -[x] [-n max_arg] [-s max_chars]\n",
bb_applet_name);
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exit(1);
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}
int main(int argc, char **argv)
{
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return xargs_main(argc, argv);
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}
#endif /* TEST */