hush/findutils/xargs.c

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/*
* Mini xargs implementation for busybox
* Only "-prt" options are supported in this version of xargs.
*
* (C) 2002 by Vladimir Oleynik <dzo@simtreas.ru>
*
* Special thanks Mark Whitley for stimul to rewrote :)
*
* 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
*
*/
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#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <getopt.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/wait.h>
#include "busybox.h"
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/*
This function have special algorithm.
Don`t use fork and include to main!
*/
static void xargs_exec(char * const * args)
{
int p;
int common[4]; /* shared vfork stack */
common[0] = 0;
if ((p = vfork()) >= 0) {
if (p == 0) {
/* vfork -- child */
execvp(args[0], args);
common[0] = errno; /* set error to shared stack */
_exit(1);
} else {
/* vfork -- parent */
wait(NULL);
if(common[0]) {
errno = common[0];
perror_msg_and_die("%s", args[0]);
}
}
} else {
perror_msg_and_die("vfork");
}
}
int xargs_main(int argc, char **argv)
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{
char *file_to_act_on;
char **args;
int i, a;
char flg_vi = 0; /* verbose |& interactive */
char flg_no_empty = 0;
while ((a = getopt(argc, argv, "prt")) > 0) {
switch(a) {
case 'p':
flg_vi |= 3;
break;
case 't':
flg_vi |= 1;
break;
case 'r':
flg_no_empty = 1;
break;
default:
show_usage();
}
}
a = argc - optind;
argv += optind;
if(a==0) {
/* default behavior is to echo all the filenames */
*argv = "/bin/echo";
a++;
}
/* allocating pointers for execvp: a*arg, arg from stdin, NULL */
args = xcalloc(a + 3, sizeof(char *));
/* Store the command to be executed (taken from the command line) */
for (i = 0; i < a; i++)
args[i] = *argv++;
/* Now, read in one line at a time from stdin, and store this
* line to be used later as an argument to the command */
while ((file_to_act_on = get_line_from_file(stdin)) != NULL) {
/* eat the newline off the filename. */
chomp(file_to_act_on);
if(file_to_act_on[0] != 0 || flg_no_empty == 0) {
args[a] = file_to_act_on[0] ? file_to_act_on : NULL;
if(flg_vi) {
for(i=0; args[i]; i++) {
if(i)
fputc(' ', stderr);
fputs(args[i], stderr);
}
fprintf(stderr, "%s", ((flg_vi & 2) ? " ?..." : "\n"));
}
if((flg_vi & 2) == 0 || ask_confirmation() != 0 ) {
xargs_exec(args);
}
}
/* clean up */
free(file_to_act_on);
}
#ifdef CONFIG_FEATURE_CLEAN_UP
free(args);
#endif
return 0;
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}