freebsd-dev/lib/libc/gen/popen.c
Jeffrey Hsu e78bad2371 Don't cast void functions to void.
Obtained from: NetBSD commit by jtc on June 16, 1995.
1995-06-20 18:31:16 +00:00

161 lines
4.3 KiB
C

/*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)popen.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#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>
static struct pid {
struct pid *next;
FILE *fp;
pid_t pid;
} *pidlist;
FILE *
popen(program, type)
const char *program;
const char *type;
{
struct pid *cur;
FILE *iop;
int pdes[2], pid;
if (*type != 'r' && *type != 'w' || type[1])
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. */
if (*type == 'r') {
if (pdes[1] != STDOUT_FILENO) {
(void)dup2(pdes[1], STDOUT_FILENO);
(void)close(pdes[1]);
}
(void) close(pdes[0]);
} else {
if (pdes[0] != STDIN_FILENO) {
(void)dup2(pdes[0], STDIN_FILENO);
(void)close(pdes[0]);
}
(void)close(pdes[1]);
}
execl(_PATH_BSHELL, "sh", "-c", program, 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(iop)
FILE *iop;
{
register struct pid *cur, *last;
int omask;
union wait pstat;
pid_t pid;
(void)fclose(iop);
/* 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);
/* Get the status of the process. */
omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP));
do {
pid = waitpid(cur->pid, (int *) &pstat, 0);
} while (pid == -1 && errno == EINTR);
(void)sigsetmask(omask);
/* 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.w_status);
}