EVOLUTION-NINJA

Edit File: runcmd.c

/***************************************************************************** * * Nagios run command utilities * * License: GPL * Copyright (c) 2005-2014 Nagios Plugins Development Team * * Description : * * A simple interface to executing programs from other programs, using an * optimized and safe popen()-like implementation. It is considered safe * in that no shell needs to be spawned and the environment passed to the * execve()'d program is essentially empty. * * The code in this file is a derivative of popen.c which in turn was taken * from "Advanced Programming for the Unix Environment" by W. Richard Stevens. * * Care has been taken to make sure the functions are async-safe. The one * function which isn't is np_runcmd_init() which it doesn't make sense to * call twice anyway, so the api as a whole should be considered async-safe. * * * 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 3 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, see <http://www.gnu.org/licenses/>. * * *****************************************************************************/ #define NAGIOSPLUG_API_C 1 /** includes **/ #include "runcmd.h" #ifdef HAVE_SYS_WAIT_H # include <sys/wait.h> #endif /** macros **/ #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 /* This variable must be global, since there's no way the caller * can forcibly slay a dead or ungainly running program otherwise. * Multithreading apps and plugins can initialize it (via NP_RUNCMD_INIT) * in an async safe manner PRIOR to calling np_runcmd() for the first time. * * The check for initialized values is atomic and can * occur in any number of threads simultaneously. */ static pid_t *np_pids = NULL; /* Try sysconf(_SC_OPEN_MAX) first, as it can be higher than OPEN_MAX. * If that fails and the macro isn't defined, we fall back to an educated * guess. There's no guarantee that our guess is adequate and the program * will die with SIGSEGV if it isn't and the upper boundary is breached. */ #ifdef _SC_OPEN_MAX static long maxfd = 0; #elif defined(OPEN_MAX) # define maxfd OPEN_MAX #else /* sysconf macro unavailable, so guess (may be wildly inaccurate) */ # define maxfd 256 #endif /** prototypes **/ static int np_runcmd_open(const char *, int *, int *) __attribute__((__nonnull__(1, 2, 3))); static int np_fetch_output(int, output *, int) __attribute__((__nonnull__(2))); static int np_runcmd_close(int); /* prototype imported from utils.h */ extern void die (int, const char *, ...) __attribute__((__noreturn__,__format__(__printf__, 2, 3))); /* this function is NOT async-safe. It is exported so multithreaded * plugins (or other apps) can call it prior to running any commands * through this api and thus achieve async-safeness throughout the api */ void np_runcmd_init(void) { #ifndef maxfd if(!maxfd && (maxfd = sysconf(_SC_OPEN_MAX)) < 0) { /* possibly log or emit a warning here, since there's no * guarantee that our guess at maxfd will be adequate */ maxfd = 256; } #endif if(!np_pids) np_pids = calloc(maxfd, sizeof(pid_t)); } /* Start running a command */ static int np_runcmd_open(const char *cmdstring, int *pfd, int *pfderr) { char *env[2]; char *cmd = NULL; char **argv = NULL; char *str; int argc; size_t cmdlen; pid_t pid; #ifdef RLIMIT_CORE struct rlimit limit; #endif int i = 0; if(!np_pids) NP_RUNCMD_INIT; env[0] = strdup("LC_ALL=C"); env[1] = '\0'; /* if no command was passed, return with no error */ if (cmdstring == NULL) return -1; /* make copy of command string so strtok() doesn't silently modify it */ /* (the calling program may want to access it later) */ cmdlen = strlen(cmdstring); if((cmd = malloc(cmdlen + 1)) == NULL) return -1; memcpy(cmd, cmdstring, cmdlen); cmd[cmdlen] = '\0'; /* This is not a shell, so we don't handle "???" */ if (strstr (cmdstring, "\"")) return -1; /* allow single quotes, but only if non-whitesapce doesn't occur on both sides */ if (strstr (cmdstring, " ' ") || strstr (cmdstring, "'''")) return -1; /* each arg must be whitespace-separated, so args can be a maximum * of (len / 2) + 1. We add 1 extra to the mix for NULL termination */ argc = (cmdlen >> 1) + 2; argv = calloc(sizeof(char *), argc); if (argv == NULL) { printf ("%s\n", _("Could not malloc argv array in popen()")); return -1; } /* get command arguments (stupidly, but fairly quickly) */ while (cmd) { str = cmd; str += strspn (str, " \t\r\n"); /* trim any leading whitespace */ if (strstr (str, "'") == str) { /* handle SIMPLE quoted strings */ str++; if (!strstr (str, "'")) return -1; /* 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; } if (pipe(pfd) < 0 || pipe(pfderr) < 0 || (pid = fork()) < 0) return -1; /* errno set by the failing function */ /* child runs exceve() and _exit. */ if (pid == 0) { #ifdef RLIMIT_CORE /* the program we execve shouldn't leave core files */ getrlimit (RLIMIT_CORE, &limit); limit.rlim_cur = 0; setrlimit (RLIMIT_CORE, &limit); #endif 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 np_pids[] * This is executed in a separate address space (pure child), * so we don't have to worry about async safety */ for (i = 0; i < maxfd; i++) if(np_pids[i] > 0) close (i); execve (argv[0], argv, env); _exit (STATE_UNKNOWN); } /* parent picks up execution here */ /* close childs descriptors in our address space */ close(pfd[1]); close(pfderr[1]); /* tag our file's entry in the pid-list and return it */ np_pids[pfd[0]] = pid; return pfd[0]; } static int np_runcmd_close(int fd) { int status; pid_t pid; /* make sure this fd was opened by popen() */ if(fd < 0 || fd > maxfd || !np_pids || (pid = np_pids[fd]) == 0) return -1; np_pids[fd] = 0; if (close (fd) == -1) return -1; /* EINTR is ok (sort of), everything else is bad */ while (waitpid (pid, &status, 0) < 0) if (errno != EINTR) return -1; /* return child's termination status */ return (WIFEXITED(status)) ? WEXITSTATUS(status) : -1; } void runcmd_timeout_alarm_handler (int signo) { size_t i; if (signo == SIGALRM) puts(_("CRITICAL - Plugin timed out while executing system call\n")); if(np_pids) for(i = 0; i < maxfd; i++) { if(np_pids[i] != 0) kill(np_pids[i], SIGKILL); } exit (STATE_CRITICAL); } static int np_fetch_output(int fd, output *op, int flags) { size_t len = 0, i = 0, lineno = 0; size_t rsf = 6, ary_size = 0; /* rsf = right shift factor, dec'ed uncond once */ char *buf = NULL; int ret; char tmpbuf[4096]; op->buf = NULL; op->buflen = 0; while((ret = read(fd, tmpbuf, sizeof(tmpbuf))) > 0) { len = (size_t)ret; op->buf = realloc(op->buf, op->buflen + len + 1); memcpy(op->buf + op->buflen, tmpbuf, len); op->buflen += len; i++; } if(ret < 0) { printf("read() returned %d: %s\n", ret, strerror(errno)); return ret; } /* some plugins may want to keep output unbroken, and some commands * will yield no output, so return here for those */ if(flags & RUNCMD_NO_ARRAYS || !op->buf || !op->buflen) return op->buflen; /* and some may want both */ if(flags & RUNCMD_NO_ASSOC) { buf = malloc(op->buflen); memcpy(buf, op->buf, op->buflen); } else buf = op->buf; op->line = NULL; op->lens = NULL; i = 0; while(i < op->buflen) { /* make sure we have enough memory */ if(lineno >= ary_size) { /* ary_size must never be zero */ do { ary_size = op->buflen >> --rsf; } while(!ary_size); op->line = realloc(op->line, ary_size * sizeof(char *)); op->lens = realloc(op->lens, ary_size * sizeof(size_t)); } /* set the pointer to the string */ op->line[lineno] = &buf[i]; /* hop to next newline or end of buffer */ while(buf[i] != '\n' && i < op->buflen) i++; buf[i] = '\0'; /* calculate the string length using pointer difference */ op->lens[lineno] = (size_t)&buf[i] - (size_t)op->line[lineno]; lineno++; i++; } return lineno; } int np_runcmd(const char *cmd, output *out, output *err, int flags) { int fd, pfd_out[2], pfd_err[2]; /* initialize the structs */ if(out) memset(out, 0, sizeof(output)); if(err) memset(err, 0, sizeof(output)); if((fd = np_runcmd_open(cmd, pfd_out, pfd_err)) == -1) die (STATE_UNKNOWN, _("Could not open pipe: %s\n"), cmd); if(out) out->lines = np_fetch_output(pfd_out[0], out, flags); if(err) err->lines = np_fetch_output(pfd_err[0], err, flags); return np_runcmd_close(fd); }