1 /*****************************************************************************
3 * Nagios run command utilities
6 * Copyright (c) 2005-2006 Nagios Plugins Development Team
10 * A simple interface to executing programs from other programs, using an
11 * optimized and safe popen()-like implementation. It is considered safe
12 * in that no shell needs to be spawned and the environment passed to the
13 * execve()'d program is essentially empty.
15 * The code in this file is a derivative of popen.c which in turn was taken
16 * from "Advanced Programming for the Unix Environment" by W. Richard Stevens.
18 * Care has been taken to make sure the functions are async-safe. The one
19 * function which isn't is cmd_init() which it doesn't make sense to
20 * call twice anyway, so the api as a whole should be considered async-safe.
23 * This program is free software: you can redistribute it and/or modify
24 * it under the terms of the GNU General Public License as published by
25 * the Free Software Foundation, either version 3 of the License, or
26 * (at your option) any later version.
28 * This program is distributed in the hope that it will be useful,
29 * but WITHOUT ANY WARRANTY; without even the implied warranty of
30 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
31 * GNU General Public License for more details.
33 * You should have received a copy of the GNU General Public License
34 * along with this program. If not, see <http://www.gnu.org/licenses/>.
37 *****************************************************************************/
39 #define NAGIOSPLUG_API_C 1
43 #include "utils_cmd.h"
44 #include "utils_base.h"
47 #ifdef HAVE_SYS_WAIT_H
48 # include <sys/wait.h>
53 # define WEXITSTATUS(stat_val) ((unsigned)(stat_val) >> 8)
57 # define WIFEXITED(stat_val) (((stat_val) & 255) == 0)
60 /* 4.3BSD Reno <signal.h> doesn't define SIG_ERR */
61 #if defined(SIG_IGN) && !defined(SIG_ERR)
62 # define SIG_ERR ((Sigfunc *)-1)
65 /* This variable must be global, since there's no way the caller
66 * can forcibly slay a dead or ungainly running program otherwise.
67 * Multithreading apps and plugins can initialize it (via CMD_INIT)
68 * in an async safe manner PRIOR to calling cmd_run() or cmd_run_array()
71 * The check for initialized values is atomic and can
72 * occur in any number of threads simultaneously. */
73 static pid_t
*_cmd_pids
= NULL
;
75 /* Try sysconf(_SC_OPEN_MAX) first, as it can be higher than OPEN_MAX.
76 * If that fails and the macro isn't defined, we fall back to an educated
77 * guess. There's no guarantee that our guess is adequate and the program
78 * will die with SIGSEGV if it isn't and the upper boundary is breached. */
80 static long maxfd
= 0;
81 #elif defined(OPEN_MAX)
82 # define maxfd OPEN_MAX
83 #else /* sysconf macro unavailable, so guess (may be wildly inaccurate) */
89 static int _cmd_open (char *const *, int *, int *)
90 __attribute__ ((__nonnull__ (1, 2, 3)));
92 static int _cmd_fetch_output (int, output
*, int)
93 __attribute__ ((__nonnull__ (2)));
95 static int _cmd_close (int);
97 /* prototype imported from utils.h */
98 extern void die (int, const char *, ...)
99 __attribute__ ((__noreturn__
, __format__ (__printf__
, 2, 3)));
102 /* this function is NOT async-safe. It is exported so multithreaded
103 * plugins (or other apps) can call it prior to running any commands
104 * through this api and thus achieve async-safeness throughout the api */
109 if (!maxfd
&& (maxfd
= sysconf (_SC_OPEN_MAX
)) < 0) {
110 /* possibly log or emit a warning here, since there's no
111 * guarantee that our guess at maxfd will be adequate */
117 _cmd_pids
= calloc (maxfd
, sizeof (pid_t
));
121 /* Start running a command, array style */
123 _cmd_open (char *const *argv
, int *pfd
, int *pfderr
)
133 /* if no command was passed, return with no error */
140 env
[0] = strdup ("LC_ALL=C");
143 if (pipe (pfd
) < 0 || pipe (pfderr
) < 0 || (pid
= fork ()) < 0)
144 return -1; /* errno set by the failing function */
146 /* child runs exceve() and _exit. */
149 /* the program we execve shouldn't leave core files */
150 getrlimit (RLIMIT_CORE
, &limit
);
152 setrlimit (RLIMIT_CORE
, &limit
);
155 if (pfd
[1] != STDOUT_FILENO
) {
156 dup2 (pfd
[1], STDOUT_FILENO
);
160 if (pfderr
[1] != STDERR_FILENO
) {
161 dup2 (pfderr
[1], STDERR_FILENO
);
165 /* close all descriptors in _cmd_pids[]
166 * This is executed in a separate address space (pure child),
167 * so we don't have to worry about async safety */
168 for (i
= 0; i
< maxfd
; i
++)
169 if (_cmd_pids
[i
] > 0)
172 execve (argv
[0], argv
, env
);
173 _exit (STATE_UNKNOWN
);
176 /* parent picks up execution here */
177 /* close childs descriptors in our address space */
181 /* tag our file's entry in the pid-list and return it */
182 _cmd_pids
[pfd
[0]] = pid
;
193 /* make sure the provided fd was opened */
194 if (fd
< 0 || fd
> maxfd
|| !_cmd_pids
|| (pid
= _cmd_pids
[fd
]) == 0)
198 if (close (fd
) == -1)
201 /* EINTR is ok (sort of), everything else is bad */
202 while (waitpid (pid
, &status
, 0) < 0)
206 /* return child's termination status */
207 return (WIFEXITED (status
)) ? WEXITSTATUS (status
) : -1;
212 _cmd_fetch_output (int fd
, output
* op
, int flags
)
214 size_t len
= 0, i
= 0, lineno
= 0;
215 size_t rsf
= 6, ary_size
= 0; /* rsf = right shift factor, dec'ed uncond once */
222 while ((ret
= read (fd
, tmpbuf
, sizeof (tmpbuf
))) > 0) {
224 op
->buf
= realloc (op
->buf
, op
->buflen
+ len
+ 1);
225 memcpy (op
->buf
+ op
->buflen
, tmpbuf
, len
);
231 printf ("read() returned %d: %s\n", ret
, strerror (errno
));
235 /* some plugins may want to keep output unbroken, and some commands
236 * will yield no output, so return here for those */
237 if (flags
& CMD_NO_ARRAYS
|| !op
->buf
|| !op
->buflen
)
240 /* and some may want both */
241 if (flags
& CMD_NO_ASSOC
) {
242 buf
= malloc (op
->buflen
);
243 memcpy (buf
, op
->buf
, op
->buflen
);
251 while (i
< op
->buflen
) {
252 /* make sure we have enough memory */
253 if (lineno
>= ary_size
) {
254 /* ary_size must never be zero */
256 ary_size
= op
->buflen
>> --rsf
;
259 op
->line
= realloc (op
->line
, ary_size
* sizeof (char *));
260 op
->lens
= realloc (op
->lens
, ary_size
* sizeof (size_t));
263 /* set the pointer to the string */
264 op
->line
[lineno
] = &buf
[i
];
266 /* hop to next newline or end of buffer */
267 while (buf
[i
] != '\n' && i
< op
->buflen
)
271 /* calculate the string length using pointer difference */
272 op
->lens
[lineno
] = (size_t) & buf
[i
] - (size_t) op
->line
[lineno
];
283 cmd_run (const char *cmdstring
, output
* out
, output
* err
, int flags
)
285 int fd
, pfd_out
[2], pfd_err
[2];
292 if (cmdstring
== NULL
)
295 /* initialize the structs */
297 memset (out
, 0, sizeof (output
));
299 memset (err
, 0, sizeof (output
));
301 /* make copy of command string so strtok() doesn't silently modify it */
302 /* (the calling program may want to access it later) */
303 cmdlen
= strlen (cmdstring
);
304 if ((cmd
= malloc (cmdlen
+ 1)) == NULL
)
306 memcpy (cmd
, cmdstring
, cmdlen
);
309 /* This is not a shell, so we don't handle "???" */
310 if (strstr (cmdstring
, "\"")) return -1;
312 /* allow single quotes, but only if non-whitesapce doesn't occur on both sides */
313 if (strstr (cmdstring
, " ' ") || strstr (cmdstring
, "'''"))
316 /* each arg must be whitespace-separated, so args can be a maximum
317 * of (len / 2) + 1. We add 1 extra to the mix for NULL termination */
318 argc
= (cmdlen
>> 1) + 2;
319 argv
= calloc (sizeof (char *), argc
);
322 printf ("%s\n", _("Could not malloc argv array in popen()"));
326 /* get command arguments (stupidly, but fairly quickly) */
329 str
+= strspn (str
, " \t\r\n"); /* trim any leading whitespace */
331 if (strstr (str
, "'") == str
) { /* handle SIMPLE quoted strings */
333 if (!strstr (str
, "'"))
334 return -1; /* balanced? */
335 cmd
= 1 + strstr (str
, "'");
336 str
[strcspn (str
, "'")] = 0;
339 if (strpbrk (str
, " \t\r\n")) {
340 cmd
= 1 + strpbrk (str
, " \t\r\n");
341 str
[strcspn (str
, " \t\r\n")] = 0;
348 if (cmd
&& strlen (cmd
) == strspn (cmd
, " \t\r\n"))
354 return cmd_run_array (argv
, out
, err
, flags
);
358 cmd_run_array (char *const *argv
, output
* out
, output
* err
, int flags
)
360 int fd
, pfd_out
[2], pfd_err
[2];
362 /* initialize the structs */
364 memset (out
, 0, sizeof (output
));
366 memset (err
, 0, sizeof (output
));
368 if ((fd
= _cmd_open (argv
, pfd_out
, pfd_err
)) == -1)
369 die (STATE_UNKNOWN
, _("Could not open pipe: %s\n"), argv
[0]);
372 out
->lines
= _cmd_fetch_output (pfd_out
[0], out
, flags
);
374 err
->lines
= _cmd_fetch_output (pfd_err
[0], err
, flags
);
376 return _cmd_close (fd
);
380 cmd_file_read ( char *filename
, output
*out
, int flags
)
384 memset (out
, 0, sizeof(output
));
386 if ((fd
= open(filename
, O_RDONLY
)) == -1) {
387 die( STATE_UNKNOWN
, _("Error opening %s: %s"), filename
, strerror(errno
) );
391 out
->lines
= _cmd_fetch_output (fd
, out
, flags
);