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executable file 170 lines (148 sloc) 4.326 kB
/* $OpenBSD: popen.c,v 1.17 2005/08/08 08:05:34 espie Exp $ */
/*
* Copyright (c) 1988, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software written by Ken Arnold and
* published in UNIX Review, Vol. 6, No. 8.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/param.h>
#include <sys/wait.h>
#include <signal.h>
#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <paths.h>
#include "defines.h"
static struct pid {
struct pid *next;
FILE *fp;
pid_t pid;
} *pidlist;
FILE *
__popen(const char *program, const char *type)
{
struct pid * volatile cur;
FILE *iop;
int pdes[2];
pid_t pid;
if ((*type != 'r' && *type != 'w') || type[1] != '\0') {
errno = EINVAL;
return (NULL);
}
if ((cur = malloc(sizeof(struct pid))) == NULL)
return (NULL);
if (pipe(pdes) < 0) {
free(cur);
return (NULL);
}
switch (pid = vfork()) {
case -1: /* Error. */
(void)close(pdes[0]);
(void)close(pdes[1]);
free(cur);
return (NULL);
/* NOTREACHED */
case 0: /* Child. */
{
struct pid *pcur;
/*
* because vfork() instead of fork(), must leak FILE *,
* but luckily we are terminally headed for an execl()
*/
for (pcur = pidlist; pcur; pcur = pcur->next)
close(fileno(pcur->fp));
if (*type == 'r') {
int tpdes1 = pdes[1];
(void) close(pdes[0]);
/*
* We must NOT modify pdes, due to the
* semantics of vfork.
*/
if (tpdes1 != STDOUT_FILENO) {
(void)dup2(tpdes1, STDOUT_FILENO);
(void)close(tpdes1);
tpdes1 = STDOUT_FILENO;
}
} else {
(void)close(pdes[1]);
if (pdes[0] != STDIN_FILENO) {
(void)dup2(pdes[0], STDIN_FILENO);
(void)close(pdes[0]);
}
}
execl(_PATH_BSHELL, "sh", "-c", program, (char *)NULL);
_exit(127);
/* NOTREACHED */
}
}
/* Parent; assume fdopen can't fail. */
if (*type == 'r') {
iop = fdopen(pdes[0], type);
(void)close(pdes[1]);
} else {
iop = fdopen(pdes[1], type);
(void)close(pdes[0]);
}
/* Link into list of file descriptors. */
cur->fp = iop;
cur->pid = pid;
cur->next = pidlist;
pidlist = cur;
return (iop);
}
/*
* pclose --
* Pclose returns -1 if stream is not associated with a `popened' command,
* if already `pclosed', or waitpid returns an error.
*/
int
__pclose(FILE *iop)
{
struct pid *cur, *last;
int pstat;
pid_t pid;
/* Find the appropriate file pointer. */
for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
if (cur->fp == iop)
break;
if (cur == NULL)
return (-1);
(void)fclose(iop);
do {
pid = waitpid(cur->pid, &pstat, 0);
} while (pid == -1 && errno == EINTR);
/* Remove the entry from the linked list. */
if (last == NULL)
pidlist = cur->next;
else
last->next = cur->next;
free(cur);
return (pid == -1 ? -1 : pstat);
}
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