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/******************************************************************************
* popen.c
*
* 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).
*
* $Id: popen.c,v 1.11 2004/12/25 23:17:44 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 *);
RETSIGTYPE popen_timeout_alarm_handler (int);
#include <stdarg.h> /* ANSI C header file */
#include <fcntl.h>
#include <limits.h>
#include <sys/resource.h>
#ifdef HAVE_SYS_WAIT_H
#include <sys/wait.h>
#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 <signal.h> 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} */
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 (_("Could not malloc argv array in popen()\n"));
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 (_("CRITICAL - You need more args!!!\n"));
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() */
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);
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 */
void
popen_timeout_alarm_handler (int signo)
{
if (signo == SIGALRM) {
kill (childpid[fileno (child_process)], SIGKILL);
printf (_("CRITICAL - Plugin timed out after %d seconds\n"),
timeout_interval);
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;
}
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