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/* $OpenBSD: popen.c,v 1.23 2015/01/14 17:27:30 millert 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.
* 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.
*
*/
/* this came out of the ftpd sources; it's been modified to avoid the
* globbing stuff since we don't need it. also execvp instead of execv.
*/
#include "cron.h"
#define MAX_ARGV 100
#define MAX_GARGV 1000
/*
* Special version of popen which avoids call to shell. This ensures 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;
FILE *
cron_popen(char *program, char *type, struct passwd *pw) {
char *cp;
FILE *iop;
int argc, pdes[2];
pid_t pid;
char *argv[MAX_ARGV];
if ((*type != 'r' && *type != 'w') || type[1] != '\0')
return (NULL);
if (!pids) {
if ((fds = sysconf(_SC_OPEN_MAX)) <= 0)
return (NULL);
if (!(pids = calloc(fds, sizeof(pid_t))))
return (NULL);
}
if (pipe(pdes) < 0)
return (NULL);
/* break up string into pieces */
for (argc = 0, cp = program; argc < MAX_ARGV - 1; cp = NULL)
if (!(argv[argc++] = strtok(cp, " \t\n")))
break;
argv[MAX_ARGV-1] = NULL;
switch (pid = fork()) {
case -1: /* error */
(void)close(pdes[0]);
(void)close(pdes[1]);
return (NULL);
/* NOTREACHED */
case 0: /* child */
if (pw) {
#ifdef LOGIN_CAP
if (setusercontext(0, pw, pw->pw_uid, LOGIN_SETALL) < 0) {
fprintf(stderr,
"setusercontext failed for %s\n",
pw->pw_name);
_exit(EXIT_FAILURE);
}
#else
if (setgid(pw->pw_gid) < 0 ||
initgroups(pw->pw_name, pw->pw_gid) < 0) {
fprintf(stderr,
"unable to set groups for %s\n",
pw->pw_name);
_exit(1);
}
#if (defined(BSD)) && (BSD >= 199103)
setlogin(pw->pw_name);
#endif /* BSD */
if (setuid(pw->pw_uid)) {
fprintf(stderr,
"unable to set uid for %s\n",
pw->pw_name);
_exit(1);
}
#endif /* LOGIN_CAP */
}
if (*type == 'r') {
if (pdes[1] != STDOUT_FILENO) {
dup2(pdes[1], STDOUT_FILENO);
(void)close(pdes[1]);
}
dup2(STDOUT_FILENO, STDERR_FILENO);
(void)close(pdes[0]);
} else {
if (pdes[0] != STDIN_FILENO) {
dup2(pdes[0], STDIN_FILENO);
(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;
return (iop);
}
int
cron_pclose(FILE *iop) {
int fdes;
pid_t pid;
int status;
sigset_t sigset, osigset;
/*
* 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(&sigset);
sigaddset(&sigset, SIGINT);
sigaddset(&sigset, SIGQUIT);
sigaddset(&sigset, SIGHUP);
sigprocmask(SIG_BLOCK, &sigset, &osigset);
while ((pid = waitpid(pids[fdes], &status, 0)) < 0 && errno == EINTR)
continue;
sigprocmask(SIG_SETMASK, &osigset, NULL);
pids[fdes] = 0;
if (pid < 0)
return (pid);
if (WIFEXITED(status))
return (WEXITSTATUS(status));
return (1);
}
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