/**************************************************************************** * * Nagios plugins popen * * License: GPL * Copyright (c) 2005 nagios-plugins team * * Last Modified: $Date: 2006/06/18 19:36:48 $ * * Description: * * A safe alternative to popen * * Provides spopen and spclose * * FILE * spopen(const char *); * int spclose(FILE *); * * * Code taken with liitle modification from "Advanced Programming for the Unix * Environment" by W. Richard Stevens * * This is considered safe in that no shell is spawned, and the environment and * path passed to the exec'd program are esstially empty. (popen create a shell * and passes the environment to it). * * License Information: * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. * * $Id: popen.c,v 1.15 2006/06/18 19:36:48 opensides Exp $ * ******************************************************************************/ #include "common.h" /* extern so plugin has pid to kill exec'd process on timeouts */ extern int timeout_interval; extern pid_t *childpid; extern int *child_stderr_array; extern FILE *child_process; FILE *spopen (const char *); int spclose (FILE *); #ifdef REDHAT_SPOPEN_ERROR RETSIGTYPE popen_sigchld_handler (int); #endif RETSIGTYPE popen_timeout_alarm_handler (int); #include /* ANSI C header file */ #include #include #include #ifdef HAVE_SYS_WAIT_H #include #endif #ifndef WEXITSTATUS # define WEXITSTATUS(stat_val) ((unsigned)(stat_val) >> 8) #endif #ifndef WIFEXITED # define WIFEXITED(stat_val) (((stat_val) & 255) == 0) #endif /* 4.3BSD Reno doesn't define SIG_ERR */ #if defined(SIG_IGN) && !defined(SIG_ERR) #define SIG_ERR ((Sigfunc *)-1) #endif #define min(a,b) ((a) < (b) ? (a) : (b)) #define max(a,b) ((a) > (b) ? (a) : (b)) int open_max (void); /* {Prog openmax} */ static void err_sys (const char *, ...) __attribute__((noreturn,format(printf, 1, 2))); char *rtrim (char *, const char *); char *pname = NULL; /* caller can set this from argv[0] */ /*int *childerr = NULL;*//* ptr to array allocated at run-time */ /*extern pid_t *childpid = NULL; *//* ptr to array allocated at run-time */ static int maxfd; /* from our open_max(), {Prog openmax} */ #ifdef REDHAT_SPOPEN_ERROR static volatile int childtermd = 0; #endif FILE * spopen (const char *cmdstring) { char *env[2]; char *cmd = NULL; char **argv = NULL; char *str; int argc; int i = 0, pfd[2], pfderr[2]; pid_t pid; #ifdef RLIMIT_CORE /* do not leave core files */ struct rlimit limit; getrlimit (RLIMIT_CORE, &limit); limit.rlim_cur = 0; setrlimit (RLIMIT_CORE, &limit); #endif env[0] = strdup("LC_ALL=C"); env[1] = '\0'; /* if no command was passed, return with no error */ if (cmdstring == NULL) return (NULL); /* make copy of command string so strtok() doesn't silently modify it */ /* (the calling program may want to access it later) */ cmd = malloc (strlen (cmdstring) + 1); if (cmd == NULL) return NULL; strcpy (cmd, cmdstring); /* This is not a shell, so we don't handle "???" */ if (strstr (cmdstring, "\"")) return NULL; /* allow single quotes, but only if non-whitesapce doesn't occur on both sides */ if (strstr (cmdstring, " ' ") || strstr (cmdstring, "'''")) return NULL; /* there cannot be more args than characters */ argc = strlen (cmdstring) + 1; /* add 1 for NULL termination */ argv = malloc (sizeof(char*)*argc); if (argv == NULL) { printf ("%s\n", _("Could not malloc argv array in popen()")); return NULL; } /* loop to get arguments to command */ while (cmd) { str = cmd; str += strspn (str, " \t\r\n"); /* trim any leading whitespace */ if (i >= argc - 2) { printf ("%s\n",_("CRITICAL - You need more args!!!")); return (NULL); } if (strstr (str, "'") == str) { /* handle SIMPLE quoted strings */ str++; if (!strstr (str, "'")) return NULL; /* balanced? */ cmd = 1 + strstr (str, "'"); str[strcspn (str, "'")] = 0; } else { if (strpbrk (str, " \t\r\n")) { cmd = 1 + strpbrk (str, " \t\r\n"); str[strcspn (str, " \t\r\n")] = 0; } else { cmd = NULL; } } if (cmd && strlen (cmd) == strspn (cmd, " \t\r\n")) cmd = NULL; argv[i++] = str; } argv[i] = NULL; if (childpid == NULL) { /* first time through */ maxfd = open_max (); /* allocate zeroed out array for child pids */ if ((childpid = calloc ((size_t)maxfd, sizeof (pid_t))) == NULL) return (NULL); } if (child_stderr_array == NULL) { /* first time through */ maxfd = open_max (); /* allocate zeroed out array for child pids */ if ((child_stderr_array = calloc ((size_t)maxfd, sizeof (int))) == NULL) return (NULL); } if (pipe (pfd) < 0) return (NULL); /* errno set by pipe() */ if (pipe (pfderr) < 0) return (NULL); /* errno set by pipe() */ #ifdef REDHAT_SPOPEN_ERROR if (signal (SIGCHLD, popen_sigchld_handler) == SIG_ERR) { usage4 (_("Cannot catch SIGCHLD")); } #endif if ((pid = fork ()) < 0) return (NULL); /* errno set by fork() */ else if (pid == 0) { /* child */ close (pfd[0]); if (pfd[1] != STDOUT_FILENO) { dup2 (pfd[1], STDOUT_FILENO); close (pfd[1]); } close (pfderr[0]); if (pfderr[1] != STDERR_FILENO) { dup2 (pfderr[1], STDERR_FILENO); close (pfderr[1]); } /* close all descriptors in childpid[] */ for (i = 0; i < maxfd; i++) if (childpid[i] > 0) close (i); execve (argv[0], argv, env); _exit (0); } close (pfd[1]); /* parent */ if ((child_process = fdopen (pfd[0], "r")) == NULL) return (NULL); close (pfderr[1]); childpid[fileno (child_process)] = pid; /* remember child pid for this fd */ child_stderr_array[fileno (child_process)] = pfderr[0]; /* remember STDERR */ return (child_process); } int spclose (FILE * fp) { int fd, status; pid_t pid; if (childpid == NULL) return (1); /* popen() has never been called */ fd = fileno (fp); if ((pid = childpid[fd]) == 0) return (1); /* fp wasn't opened by popen() */ childpid[fd] = 0; if (fclose (fp) == EOF) return (1); #ifdef REDHAT_SPOPEN_ERROR while (!childtermd); /* wait until SIGCHLD */ #endif while (waitpid (pid, &status, 0) < 0) if (errno != EINTR) return (1); /* error other than EINTR from waitpid() */ if (WIFEXITED (status)) return (WEXITSTATUS (status)); /* return child's termination status */ return (1); } #ifdef OPEN_MAX static int openmax = OPEN_MAX; #else static int openmax = 0; #endif #define OPEN_MAX_GUESS 256 /* if OPEN_MAX is indeterminate */ /* no guarantee this is adequate */ #ifdef REDHAT_SPOPEN_ERROR RETSIGTYPE popen_sigchld_handler (int signo) { if (signo == SIGCHLD) childtermd = 1; } #endif RETSIGTYPE popen_timeout_alarm_handler (int signo) { int fh; if (signo == SIGALRM) { if (child_process != NULL) { fh=fileno (child_process); if(fh >= 0){ kill (childpid[fh], SIGKILL); } printf (_("CRITICAL - Plugin timed out after %d seconds\n"), timeout_interval); } else { printf ("%s\n", _("CRITICAL - popen timeout received, but no child process")); } exit (STATE_CRITICAL); } } int open_max (void) { if (openmax == 0) { /* first time through */ errno = 0; if ((openmax = sysconf (_SC_OPEN_MAX)) < 0) { if (errno == 0) openmax = OPEN_MAX_GUESS; /* it's indeterminate */ else err_sys (_("sysconf error for _SC_OPEN_MAX")); } } return (openmax); } /* Fatal error related to a system call. * Print a message and die. */ #define MAXLINE 2048 static void err_sys (const char *fmt, ...) { int errnoflag = 1; int errno_save; char buf[MAXLINE]; va_list ap; va_start (ap, fmt); /* err_doit (1, fmt, ap); */ errno_save = errno; /* value caller might want printed */ vsprintf (buf, fmt, ap); if (errnoflag) sprintf (buf + strlen (buf), ": %s", strerror (errno_save)); strcat (buf, "\n"); fflush (stdout); /* in case stdout and stderr are the same */ fputs (buf, stderr); fflush (NULL); /* flushes all stdio output streams */ va_end (ap); exit (1); } char * rtrim (char *str, const char *tok) { int i = 0; int j = sizeof (str); while (str != NULL && i < j) { if (*(str + i) == *tok) { sprintf (str + i, "%s", "\0"); return str; } i++; } return str; }