1 files changed, 378 insertions, 0 deletions

diff --git a/lib/utils_cmd.c b/lib/utils_cmd.c
new file mode 100644
index 00000000..c4ceb97e
--- /dev/null
+++ b/lib/utils_cmd.c
@@ -0,0 +1,378 @@
+/****************************************************************************
+ * Nagios run command utilities
+ *
+ * License: GPL
+ * Copyright (c) 2005 nagios-plugins team
+ *
+ * $Id: utils_cmd.c 1434 2006-06-18 19:36:48Z opensides $
+ *
+ * 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 cmd_init() which it doesn't make sense to
+ * call twice anyway, so the api as a whole should be considered async-safe.
+ *
+ * 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.
+ */
+
+#define NAGIOSPLUG_API_C 1
+
+/** includes **/
+#include "common.h"
+#include "utils_cmd.h"
+#include "utils_base.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 CMD_INIT)
+ * in an async safe manner PRIOR to calling cmd_run() or cmd_run_array()
+ * for the first time.
+ *
+ * The check for initialized values is atomic and can
+ * occur in any number of threads simultaneously. */
+static pid_t *_cmd_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 _cmd_open (char *const *, int *, int *)
+        __attribute__ ((__nonnull__ (1, 2, 3)));
+
+static int _cmd_fetch_output (int, output *, int)
+        __attribute__ ((__nonnull__ (2)));
+
+static int _cmd_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
+cmd_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 (!_cmd_pids)
+                _cmd_pids = calloc (maxfd, sizeof (pid_t));
+}
+
+
+/* Start running a command, array style */
+static int
+_cmd_open (char *const *argv, int *pfd, int *pfderr)
+{
+        char *env[2];
+        pid_t pid;
+#ifdef RLIMIT_CORE
+        struct rlimit limit;
+#endif
+
+        int i = 0;
+
+        /* if no command was passed, return with no error */
+        if (argv == NULL)
+                return -1;
+
+        if (!_cmd_pids)
+                CMD_INIT;
+
+        env[0] = strdup ("LC_ALL=C");
+        env[1] = '\0';
+
+        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 _cmd_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 (_cmd_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 */
+        _cmd_pids[pfd[0]] = pid;
+
+        return pfd[0];
+}
+
+static int
+_cmd_close (int fd)
+{
+        int status;
+        pid_t pid;
+
+        /* make sure the provided fd was opened */
+        if (fd < 0 || fd > maxfd || !_cmd_pids || (pid = _cmd_pids[fd]) == 0)
+                return -1;
+
+        _cmd_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;
+}
+
+
+static int
+_cmd_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 & CMD_NO_ARRAYS || !op->buf || !op->buflen)
+                return op->buflen;
+
+        /* and some may want both */
+        if (flags & CMD_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
+cmd_run (const char *cmdstring, output * out, output * err, int flags)
+{
+        int fd, pfd_out[2], pfd_err[2];
+        int i = 0, argc;
+        size_t cmdlen;
+        char **argv = NULL;
+        char *cmd = NULL;
+        char *str = NULL;
+
+        if (cmdstring == NULL)
+                return -1;
+
+        /* initialize the structs */
+        if (out)
+                memset (out, 0, sizeof (output));
+        if (err)
+                memset (err, 0, sizeof (output));
+
+        /* 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;
+        }
+
+        return cmd_run_array (argv, out, err, flags);
+}
+
+int
+cmd_run_array (char *const *argv, 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 = _cmd_open (argv, pfd_out, pfd_err)) == -1)
+                die (STATE_UNKNOWN, _("Could not open pipe: %s\n"), argv[0]);
+
+        if (out)
+                out->lines = _cmd_fetch_output (pfd_out[0], out, flags);
+        if (err)
+                err->lines = _cmd_fetch_output (pfd_err[0], err, flags);
+
+        return _cmd_close (fd);
+}