342 lines
7.8 KiB
C
342 lines
7.8 KiB
C
/******************************************************************************
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* popen.c
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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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FILE * spopen(const char *);
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int spclose(FILE *);
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*
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* Code taken with liitle 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 and
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* path passed to the exec'd program are esstially empty. (popen create a shell
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* and passes the environment to it).
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*
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* $Id: popen.c,v 1.13 2005/09/12 10:31:28 tonvoon Exp $
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*
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******************************************************************************/
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#include "common.h"
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/* extern so plugin has pid to kill exec'd process on timeouts */
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extern int timeout_interval;
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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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RETSIGTYPE popen_sigchld_handler (int);
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#endif
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RETSIGTYPE 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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#define min(a,b) ((a) < (b) ? (a) : (b))
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#define max(a,b) ((a) > (b) ? (a) : (b))
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int open_max (void); /* {Prog openmax} */
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static void err_sys (const char *, ...) __attribute__((noreturn,format(printf, 1, 2)));
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char *rtrim (char *, const char *);
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char *pname = NULL; /* caller can set this from argv[0] */
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/*int *childerr = NULL;*//* ptr to array allocated at run-time */
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/*extern pid_t *childpid = NULL; *//* ptr to array allocated at run-time */
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static int maxfd; /* from our open_max(), {Prog openmax} */
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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;
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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 (_("Could not malloc argv array in popen()\n"));
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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 (_("CRITICAL - You need more args!!!\n"));
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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 {
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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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if (childpid == NULL) { /* first time through */
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maxfd = open_max (); /* allocate zeroed out array for child pids */
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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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maxfd = open_max (); /* allocate zeroed out array for child pids */
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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 OPEN_MAX
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static int openmax = OPEN_MAX;
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#else
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static int openmax = 0;
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#endif
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#define OPEN_MAX_GUESS 256 /* if OPEN_MAX is indeterminate */
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/* no guarantee this is adequate */
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#ifdef REDHAT_SPOPEN_ERROR
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RETSIGTYPE
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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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RETSIGTYPE
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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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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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exit (STATE_CRITICAL);
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}
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}
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int
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open_max (void)
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{
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if (openmax == 0) { /* first time through */
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errno = 0;
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if ((openmax = sysconf (_SC_OPEN_MAX)) < 0) {
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if (errno == 0)
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openmax = OPEN_MAX_GUESS; /* it's indeterminate */
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else
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err_sys (_("sysconf error for _SC_OPEN_MAX"));
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}
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}
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return (openmax);
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}
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/* Fatal error related to a system call.
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* Print a message and die. */
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#define MAXLINE 2048
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static void
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err_sys (const char *fmt, ...)
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{
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int errnoflag = 1;
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int errno_save;
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char buf[MAXLINE];
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va_list ap;
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va_start (ap, fmt);
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/* err_doit (1, fmt, ap); */
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errno_save = errno; /* value caller might want printed */
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vsprintf (buf, fmt, ap);
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if (errnoflag)
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sprintf (buf + strlen (buf), ": %s", strerror (errno_save));
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strcat (buf, "\n");
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fflush (stdout); /* in case stdout and stderr are the same */
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fputs (buf, stderr);
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fflush (NULL); /* flushes all stdio output streams */
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va_end (ap);
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exit (1);
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}
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char *
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rtrim (char *str, const char *tok)
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{
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int i = 0;
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int j = sizeof (str);
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while (str != NULL && i < j) {
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if (*(str + i) == *tok) {
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sprintf (str + i, "%s", "\0");
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return str;
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}
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i++;
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}
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return str;
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}
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