295 lines
7 KiB
C
295 lines
7 KiB
C
/*****************************************************************************
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*
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* Monitoring Plugins popen
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*
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* License: GPL
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* Copyright (c) 2005-2007 Monitoring Plugins Development Team
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*
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* Description:
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*
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* A safe alternative to popen
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*
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* Provides spopen and spclose
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*
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* FILE * spopen(const char *);
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* int spclose(FILE *);
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*
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* Code taken with little modification from "Advanced Programming for the Unix
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* Environment" by W. Richard Stevens
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*
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* This is considered safe in that no shell is spawned, and the environment
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* and path passed to the exec'd program are essentially empty. (popen create
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* a shell and passes the environment to it).
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*
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*
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*****************************************************************************/
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#include "./common.h"
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#include "./utils.h"
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#include "../lib/maxfd.h"
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/* extern so plugin has pid to kill exec'd process on timeouts */
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extern pid_t *childpid;
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extern int *child_stderr_array;
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extern FILE *child_process;
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FILE *spopen (const char *);
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int spclose (FILE *);
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#ifdef REDHAT_SPOPEN_ERROR
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void popen_sigchld_handler (int);
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#endif
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void popen_timeout_alarm_handler (int);
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#include <stdarg.h> /* ANSI C header file */
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#include <fcntl.h>
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#include <limits.h>
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#include <sys/resource.h>
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#ifdef HAVE_SYS_WAIT_H
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#include <sys/wait.h>
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#endif
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#ifndef WEXITSTATUS
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# define WEXITSTATUS(stat_val) ((unsigned)(stat_val) >> 8)
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#endif
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#ifndef WIFEXITED
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# define WIFEXITED(stat_val) (((stat_val) & 255) == 0)
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#endif
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/* 4.3BSD Reno <signal.h> doesn't define SIG_ERR */
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#if defined(SIG_IGN) && !defined(SIG_ERR)
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#define SIG_ERR ((Sigfunc *)-1)
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#endif
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char *pname = NULL; /* caller can set this from argv[0] */
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#ifdef REDHAT_SPOPEN_ERROR
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static volatile int childtermd = 0;
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#endif
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FILE *
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spopen (const char *cmdstring)
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{
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char *env[2];
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char *cmd = NULL;
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char **argv = NULL;
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char *str, *tmp;
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int argc;
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int i = 0, pfd[2], pfderr[2];
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pid_t pid;
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#ifdef RLIMIT_CORE
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/* do not leave core files */
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struct rlimit limit;
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getrlimit (RLIMIT_CORE, &limit);
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limit.rlim_cur = 0;
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setrlimit (RLIMIT_CORE, &limit);
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#endif
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env[0] = strdup("LC_ALL=C");
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env[1] = '\0';
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/* if no command was passed, return with no error */
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if (cmdstring == NULL)
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return (NULL);
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/* make copy of command string so strtok() doesn't silently modify it */
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/* (the calling program may want to access it later) */
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cmd = malloc (strlen (cmdstring) + 1);
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if (cmd == NULL)
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return NULL;
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strcpy (cmd, cmdstring);
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/* This is not a shell, so we don't handle "???" */
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if (strstr (cmdstring, "\""))
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return NULL;
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/* allow single quotes, but only if non-whitesapce doesn't occur on both sides */
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if (strstr (cmdstring, " ' ") || strstr (cmdstring, "'''"))
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return NULL;
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/* there cannot be more args than characters */
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argc = strlen (cmdstring) + 1; /* add 1 for NULL termination */
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argv = malloc (sizeof(char*)*argc);
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if (argv == NULL) {
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printf ("%s\n", _("Could not malloc argv array in popen()"));
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return NULL;
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}
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/* loop to get arguments to command */
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while (cmd) {
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str = cmd;
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str += strspn (str, " \t\r\n"); /* trim any leading whitespace */
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if (i >= argc - 2) {
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printf ("%s\n",_("CRITICAL - You need more args!!!"));
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return (NULL);
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}
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if (strstr (str, "'") == str) { /* handle SIMPLE quoted strings */
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str++;
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if (!strstr (str, "'"))
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return NULL; /* balanced? */
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cmd = 1 + strstr (str, "'");
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str[strcspn (str, "'")] = 0;
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}
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else if (strcspn(str,"'") < strcspn (str, " \t\r\n")) {
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/* handle --option='foo bar' strings */
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tmp = str + strcspn(str, "'") + 1;
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if (!strstr (tmp, "'"))
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return NULL; /* balanced? */
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tmp += strcspn(tmp,"'") + 1;
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*tmp = 0;
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cmd = tmp + 1;
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} else {
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if (strpbrk (str, " \t\r\n")) {
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cmd = 1 + strpbrk (str, " \t\r\n");
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str[strcspn (str, " \t\r\n")] = 0;
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}
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else {
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cmd = NULL;
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}
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}
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if (cmd && strlen (cmd) == strspn (cmd, " \t\r\n"))
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cmd = NULL;
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argv[i++] = str;
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}
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argv[i] = NULL;
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long maxfd = mp_open_max();
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if (childpid == NULL) { /* first time through */
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if ((childpid = calloc ((size_t)maxfd, sizeof (pid_t))) == NULL)
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return (NULL);
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}
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if (child_stderr_array == NULL) { /* first time through */
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if ((child_stderr_array = calloc ((size_t)maxfd, sizeof (int))) == NULL)
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return (NULL);
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}
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if (pipe (pfd) < 0)
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return (NULL); /* errno set by pipe() */
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if (pipe (pfderr) < 0)
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return (NULL); /* errno set by pipe() */
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#ifdef REDHAT_SPOPEN_ERROR
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if (signal (SIGCHLD, popen_sigchld_handler) == SIG_ERR) {
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usage4 (_("Cannot catch SIGCHLD"));
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}
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#endif
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if ((pid = fork ()) < 0)
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return (NULL); /* errno set by fork() */
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else if (pid == 0) { /* child */
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close (pfd[0]);
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if (pfd[1] != STDOUT_FILENO) {
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dup2 (pfd[1], STDOUT_FILENO);
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close (pfd[1]);
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}
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close (pfderr[0]);
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if (pfderr[1] != STDERR_FILENO) {
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dup2 (pfderr[1], STDERR_FILENO);
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close (pfderr[1]);
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}
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/* close all descriptors in childpid[] */
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for (i = 0; i < maxfd; i++)
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if (childpid[i] > 0)
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close (i);
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execve (argv[0], argv, env);
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_exit (0);
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}
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close (pfd[1]); /* parent */
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if ((child_process = fdopen (pfd[0], "r")) == NULL)
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return (NULL);
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close (pfderr[1]);
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childpid[fileno (child_process)] = pid; /* remember child pid for this fd */
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child_stderr_array[fileno (child_process)] = pfderr[0]; /* remember STDERR */
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return (child_process);
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}
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int
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spclose (FILE * fp)
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{
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int fd, status;
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pid_t pid;
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if (childpid == NULL)
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return (1); /* popen() has never been called */
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fd = fileno (fp);
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if ((pid = childpid[fd]) == 0)
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return (1); /* fp wasn't opened by popen() */
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childpid[fd] = 0;
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if (fclose (fp) == EOF)
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return (1);
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#ifdef REDHAT_SPOPEN_ERROR
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while (!childtermd); /* wait until SIGCHLD */
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#endif
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while (waitpid (pid, &status, 0) < 0)
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if (errno != EINTR)
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return (1); /* error other than EINTR from waitpid() */
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if (WIFEXITED (status))
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return (WEXITSTATUS (status)); /* return child's termination status */
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return (1);
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}
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#ifdef REDHAT_SPOPEN_ERROR
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void
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popen_sigchld_handler (int signo)
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{
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if (signo == SIGCHLD)
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childtermd = 1;
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}
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#endif
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void
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popen_timeout_alarm_handler (int signo)
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{
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int fh;
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if (signo == SIGALRM) {
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if (child_process != NULL) {
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fh=fileno (child_process);
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if(fh >= 0){
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kill (childpid[fh], SIGKILL);
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}
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printf (_("CRITICAL - Plugin timed out after %d seconds\n"),
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timeout_interval);
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} else {
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printf ("%s\n", _("CRITICAL - popen timeout received, but no child process"));
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}
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exit (STATE_CRITICAL);
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}
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}
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