busybox/findutils/xargs.c

221 lines
5.3 KiB
C

/*
* Mini xargs implementation for busybox
* Only "-prt" options are supported in this version of xargs.
*
* (C) 2002 by Vladimir Oleynik <dzo@simtreas.ru>
* (C) 2003 by Glenn McGrath <bug1@optushome.com.au>
*
* 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
*
*
* Reference:
* http://www.opengroup.org/onlinepubs/007904975/utilities/xargs.html
*
*
* BUGS:
* p option doesnt accept user input, should read input from /dev/tty
*
* E option doesnt allow spaces before argument
*
* xargs should terminate if an invocation of a constructed command line
* returns an exit status of 255.
*
* exit value of isnt correct
*
* doesnt print quoted string properly
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <getopt.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/wait.h>
#include "busybox.h"
/*
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];
bb_perror_msg_and_die("%s", args[0]);
}
}
} else {
bb_perror_msg_and_die("vfork");
}
}
#define OPT_VERBOSE 0x2
#define OPT_INTERACTIVE 0x4
#define OPT_TERMINATE 0x8
#define OPT_UPTO_NUMBER 0x10
#define OPT_UPTO_SIZE 0x20
#define OPT_EOF_STRING 0x40
int xargs_main(int argc, char **argv)
{
char *s_max_args = NULL;
char *s_line_size = NULL;
unsigned long flg;
char *eof_string = "_";
int line_size = LINE_MAX;
unsigned int max_args = LINE_MAX / 2;
char *line_buffer = NULL;
char *line_buffer_ptr_ptr;
char *old_arg = NULL;
char **args;
char *args_entry_ptr;
int i;
int a;
bb_opt_complementaly = "pt";
flg = bb_getopt_ulflags(argc, argv, "+tpxn:s:E::", &s_max_args, &s_line_size, &eof_string);
if (s_max_args) {
max_args = bb_xgetularg10(s_max_args);
}
if (s_line_size) {
line_size = bb_xgetularg10(s_line_size);
}
a = argc - optind;
argv += optind;
if(a==0) {
/* default behavior is to echo all the filenames */
*argv = "echo";
a++;
}
/* allocating pointers for execvp: a*arg, arg from stdin, NULL */
args = xcalloc(a + 2, sizeof(char *));
/* Store the command to be executed (taken from the command line) */
for (i = 0; i < a; i++) {
line_size -= strlen(*argv) + 1;
args[i] = *argv++;
}
if (line_size < 1) {
bb_error_msg_and_die("can not fit single argument within argument list size limit");
}
args[i] = xmalloc(line_size);
args_entry_ptr = args[i];
/* Now, read in one line at a time from stdin, and store this
* line to be used later as an argument to the command */
do {
char *line_buffer_ptr = NULL;
unsigned int arg_count = 0;
unsigned int arg_size = 0;
*args_entry_ptr = '\0';
/* Get the required number of entries from stdin */
do {
/* (Re)fill the line buffer */
if (line_buffer == NULL) {
line_buffer = bb_get_chomped_line_from_file(stdin);
if (line_buffer == NULL) {
/* EOF, exit outer loop */
break;
}
line_buffer_ptr = strtok_r(line_buffer, " \t", &line_buffer_ptr_ptr);
} else {
if (old_arg) {
line_buffer_ptr = old_arg;
old_arg = NULL;
} else {
line_buffer_ptr = strtok_r(NULL, " \t", &line_buffer_ptr_ptr);
}
}
/* If no arguments left go back and get another line */
if (line_buffer_ptr == NULL) {
free(line_buffer);
line_buffer = NULL;
continue;
}
if (eof_string && (strcmp(line_buffer_ptr, eof_string) == 0)) {
/* logical EOF, exit outer loop */
line_buffer = NULL;
break;
}
/* Check the next argument will fit */
arg_size += 1 + strlen(line_buffer_ptr);
if (arg_size > line_size) {
if ((arg_count == 0) || ((flg & OPT_TERMINATE) && (arg_count != max_args))){
bb_error_msg_and_die("argument line too long");
}
old_arg = line_buffer_ptr;
break;
}
/* Add the entry to our pre-allocated space */
strcat(args_entry_ptr, line_buffer_ptr);
strcat(args_entry_ptr, " ");
arg_count++;
} while (arg_count < max_args);
if (*args_entry_ptr != '\0') {
if(flg & (OPT_VERBOSE | OPT_INTERACTIVE)) {
for(i=0; args[i]; i++) {
if(i)
fputc(' ', stderr);
fputs(args[i], stderr);
}
fputs(((flg & OPT_INTERACTIVE) ? " ?..." : "\n"), stderr);
}
if((flg & OPT_INTERACTIVE) == 0 || bb_ask_confirmation() != 0 ) {
xargs_exec(args);
}
}
} while (line_buffer);
#ifdef CONFIG_FEATURE_CLEAN_UP
free(args);
#endif
return 0;
}