/*
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* fpopen.c --- unlike the libc popen, it directly executes the
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* command instead of call out to the shell.
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*
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* Copyright Theodore Ts'o, 1996-1999.
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*
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* Permission to use this file is granted for any purposes, as long as
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* this copyright statement is kept intact and the author is not held
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* liable for any damages resulting from the use of this program.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
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* WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
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* USE OF THIS SOFTWARE.
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*/
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#include "config.h"
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#include <unistd.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <errno.h>
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#include <string.h>
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#include <ctype.h>
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#define MAX_ARGV 256
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extern FILE *fpopen(const char *cmd, const char *mode);
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FILE *fpopen(const char *cmd, const char *mode)
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{
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char *argv[MAX_ARGV];
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int i = 0;
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char *buf, *prog = 0;
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char *p;
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int do_stdin, do_stderr = 0;
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int fds[2];
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pid_t pid;
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if (!mode) {
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errno = EFAULT;
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return NULL;
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}
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switch (*mode) {
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case 'r':
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do_stdin = 0;
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break;
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case 'w':
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do_stdin = 1;
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break;
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default:
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errno = EINVAL;
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return NULL;
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}
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switch (*(mode+1)) {
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case '&':
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do_stderr = 1;
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}
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/*
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* Create the argv vector....
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*/
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buf = malloc(strlen(cmd)+1);
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if (!buf)
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return NULL;
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strcpy(buf, cmd);
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p = buf;
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while (p && *p) {
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if (isspace(*p)) {
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p++;
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continue;
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}
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if (i == 0)
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prog = p;
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argv[i++] = p;
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p = strchr(p, ' ');
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if (p)
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*p++ = 0;
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}
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argv[i] = 0;
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/*
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* Get the pipe
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*/
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if (pipe(fds) < 0)
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return NULL;
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/* Fork and execute the correct program. */
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if ((pid = fork()) < 0) {
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perror("fork");
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return NULL;
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} else if (pid == 0) {
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if (do_stdin) {
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close(fds[1]);
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dup2(fds[0], 0);
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} else {
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close(fds[0]);
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dup2(fds[1], 1);
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if (do_stderr)
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dup2(fds[1], 2);
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}
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(void) execvp(prog, argv);
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perror(prog);
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exit(1);
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}
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return fdopen(do_stdin ? fds[1] : fds[0], mode);
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}
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