NetBSD/usr.sbin/cron/popen.c

153 lines
4.0 KiB
C

/* $NetBSD: popen.c,v 1.9 2005/03/16 02:53:55 xtraeme Exp $ */
/*
* Copyright (c) 1988, 1993, 1994
* 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.
*
* 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/cdefs.h>
#ifndef lint
#if 0
static char rcsid[] = "Id: popen.c,v 1.5 1994/01/15 20:43:43 vixie Exp";
static char sccsid[] = "@(#)popen.c 5.7 (Berkeley) 2/14/89";
#else
__RCSID("$NetBSD: popen.c,v 1.9 2005/03/16 02:53:55 xtraeme Exp $");
#endif
#endif /* not lint */
#include "cron.h"
#include <signal.h>
/*
* Special version of popen which avoids call to shell. This insures noone
* may create a pipe to a hidden program as a side effect of a list or dir
* command.
*/
static PID_T *pids;
static int fds;
#define MAX_ARGS 1024
FILE *
cron_popen(char *program, const char *type)
{
char *cp;
FILE *iop;
int argc, pdes[2];
PID_T pid;
char *argv[MAX_ARGS];
#ifdef __GNUC__
(void) &iop; /* Avoid vfork clobbering */
#endif
if ((*type != 'r' && *type != 'w') || type[1])
return(NULL);
if (!pids) {
if ((fds = getdtablesize()) <= 0)
return(NULL);
if (!(pids = (PID_T *)malloc((u_int)(fds * sizeof(PID_T)))))
return(NULL);
bzero((char *)pids, fds * sizeof(PID_T));
}
if (pipe(pdes) < 0)
return(NULL);
/* break up string into pieces */
for (argc = 0, cp = program; argc < MAX_ARGS; cp = NULL)
if (!(argv[argc++] = strtok(cp, " \t\n")))
break;
iop = NULL;
switch(pid = vfork()) {
case -1: /* error */
(void)close(pdes[0]);
(void)close(pdes[1]);
goto pfree;
/* NOTREACHED */
case 0: /* child */
if (*type == 'r') {
if (pdes[1] != 1) {
dup2(pdes[1], 1);
dup2(pdes[1], 2); /* stderr, too! */
(void)close(pdes[1]);
}
(void)close(pdes[0]);
} else {
if (pdes[0] != 0) {
dup2(pdes[0], 0);
(void)close(pdes[0]);
}
(void)close(pdes[1]);
}
execvp(argv[0], argv);
_exit(1);
}
/* 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]);
}
pids[fileno(iop)] = pid;
pfree:
return(iop);
}
int
cron_pclose(FILE *iop)
{
int fdes;
sigset_t oset, nset;
WAIT_T stat_loc;
PID_T pid;
/*
* pclose returns -1 if stream is not associated with a
* `popened' command, or, if already `pclosed'.
*/
if (pids == 0 || pids[fdes = fileno(iop)] == 0)
return(-1);
(void)fclose(iop);
sigemptyset(&nset);
sigaddset(&nset, SIGINT);
sigaddset(&nset, SIGQUIT);
sigaddset(&nset, SIGHUP);
(void)sigprocmask(SIG_BLOCK, &nset, &oset);
while ((pid = wait(&stat_loc)) != pids[fdes] && pid != -1)
;
(void)sigprocmask(SIG_SETMASK, &oset, NULL);
pids[fdes] = 0;
return (pid == -1 ? -1 : WEXITSTATUS(stat_loc));
}