e7648bd7f3f66e7be405dd4042e8cf0d839b9b38
1 /**
2 * collectd - src/exec.c
3 * Copyright (C) 2007,2008 Florian octo Forster
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the
7 * Free Software Foundation; only version 2 of the License is applicable.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License along
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
17 *
18 * Authors:
19 * Florian octo Forster <octo at verplant.org>
20 **/
22 #include "collectd.h"
23 #include "common.h"
24 #include "plugin.h"
26 #include "utils_cmd_putval.h"
27 #include "utils_cmd_putnotif.h"
29 #include <sys/types.h>
30 #include <pwd.h>
31 #include <grp.h>
32 #include <signal.h>
34 #include <pthread.h>
36 #define PL_NORMAL 0x01
37 #define PL_NOTIF_ACTION 0x02
38 #define PL_NAGIOS_PLUGIN 0x04
40 #define PL_RUNNING 0x10
42 /*
43 * Private data types
44 */
45 /*
46 * Access to this structure is serialized using the `pl_lock' lock and the
47 * `PL_RUNNING' flag. The execution of notifications is *not* serialized, so
48 * all functions used to handle notifications MUST NOT write to this structure.
49 * The `pid' and `status' fields are thus unused if the `PL_NOTIF_ACTION' flag
50 * is set.
51 * The `PL_RUNNING' flag is set in `exec_read' and unset in `exec_read_one'.
52 */
53 struct program_list_s;
54 typedef struct program_list_s program_list_t;
55 struct program_list_s
56 {
57 char *user;
58 char *group;
59 char *exec;
60 char **argv;
61 int pid;
62 int status;
63 int flags;
64 program_list_t *next;
65 };
67 typedef struct program_list_and_notification_s
68 {
69 program_list_t *pl;
70 notification_t n;
71 } program_list_and_notification_t;
73 /*
74 * Private variables
75 */
76 static program_list_t *pl_head = NULL;
77 static pthread_mutex_t pl_lock = PTHREAD_MUTEX_INITIALIZER;
79 /*
80 * Functions
81 */
82 static void sigchld_handler (int signal) /* {{{ */
83 {
84 pid_t pid;
85 int status;
86 while ((pid = waitpid (-1, &status, WNOHANG)) > 0)
87 {
88 program_list_t *pl;
89 for (pl = pl_head; pl != NULL; pl = pl->next)
90 if (pl->pid == pid)
91 break;
92 if (pl != NULL)
93 pl->status = status;
94 } /* while (waitpid) */
95 } /* void sigchld_handler }}} */
97 static int exec_config_exec (oconfig_item_t *ci) /* {{{ */
98 {
99 program_list_t *pl;
100 char buffer[128];
101 int i;
103 if (ci->children_num != 0)
104 {
105 WARNING ("exec plugin: The config option `%s' may not be a block.",
106 ci->key);
107 return (-1);
108 }
109 if (ci->values_num < 2)
110 {
111 WARNING ("exec plugin: The config option `%s' needs at least two "
112 "arguments.", ci->key);
113 return (-1);
114 }
115 if ((ci->values[0].type != OCONFIG_TYPE_STRING)
116 || (ci->values[1].type != OCONFIG_TYPE_STRING))
117 {
118 WARNING ("exec plugin: The first two arguments to the `%s' option must "
119 "be string arguments.", ci->key);
120 return (-1);
121 }
123 pl = (program_list_t *) malloc (sizeof (program_list_t));
124 if (pl == NULL)
125 {
126 ERROR ("exec plugin: malloc failed.");
127 return (-1);
128 }
129 memset (pl, '\0', sizeof (program_list_t));
131 if (strcasecmp ("NagiosExec", ci->key) == 0)
132 pl->flags |= PL_NAGIOS_PLUGIN;
133 else if (strcasecmp ("NotificationExec", ci->key) == 0)
134 pl->flags |= PL_NOTIF_ACTION;
135 else
136 pl->flags |= PL_NORMAL;
138 pl->user = strdup (ci->values[0].value.string);
139 if (pl->user == NULL)
140 {
141 ERROR ("exec plugin: strdup failed.");
142 sfree (pl);
143 return (-1);
144 }
146 pl->group = strchr (pl->user, ':');
147 if (pl->group != NULL)
148 {
149 *pl->group = '\0';
150 pl->group++;
151 }
153 pl->exec = strdup (ci->values[1].value.string);
154 if (pl->exec == NULL)
155 {
156 ERROR ("exec plugin: strdup failed.");
157 sfree (pl->user);
158 sfree (pl);
159 return (-1);
160 }
162 pl->argv = (char **) malloc (ci->values_num * sizeof (char *));
163 if (pl->argv == NULL)
164 {
165 ERROR ("exec plugin: malloc failed.");
166 sfree (pl->exec);
167 sfree (pl->user);
168 sfree (pl);
169 return (-1);
170 }
171 memset (pl->argv, '\0', ci->values_num * sizeof (char *));
173 {
174 char *tmp = strrchr (ci->values[1].value.string, '/');
175 if (tmp == NULL)
176 strncpy (buffer, ci->values[1].value.string, sizeof (buffer));
177 else
178 strncpy (buffer, tmp + 1, sizeof (buffer));
179 buffer[sizeof (buffer) - 1] = '\0';
180 }
181 pl->argv[0] = strdup (buffer);
182 if (pl->argv[0] == NULL)
183 {
184 ERROR ("exec plugin: malloc failed.");
185 sfree (pl->argv);
186 sfree (pl->exec);
187 sfree (pl->user);
188 sfree (pl);
189 return (-1);
190 }
192 for (i = 1; i < (ci->values_num - 1); i++)
193 {
194 if (ci->values[i + 1].type == OCONFIG_TYPE_STRING)
195 {
196 pl->argv[i] = strdup (ci->values[i + 1].value.string);
197 }
198 else
199 {
200 if (ci->values[i + 1].type == OCONFIG_TYPE_NUMBER)
201 {
202 snprintf (buffer, sizeof (buffer), "%lf",
203 ci->values[i + 1].value.number);
204 }
205 else
206 {
207 if (ci->values[i + 1].value.boolean)
208 strncpy (buffer, "true", sizeof (buffer));
209 else
210 strncpy (buffer, "false", sizeof (buffer));
211 }
212 buffer[sizeof (buffer) - 1] = '\0';
214 pl->argv[i] = strdup (buffer);
215 }
217 if (pl->argv[i] == NULL)
218 {
219 ERROR ("exec plugin: strdup failed.");
220 break;
221 }
222 } /* for (i) */
224 if (i < (ci->values_num - 1))
225 {
226 while ((--i) >= 0)
227 {
228 sfree (pl->argv[i]);
229 }
230 sfree (pl->argv);
231 sfree (pl->exec);
232 sfree (pl->user);
233 sfree (pl);
234 return (-1);
235 }
237 for (i = 0; pl->argv[i] != NULL; i++)
238 {
239 DEBUG ("exec plugin: argv[%i] = %s", i, pl->argv[i]);
240 }
242 pl->next = pl_head;
243 pl_head = pl;
245 return (0);
246 } /* int exec_config_exec }}} */
248 static int exec_config (oconfig_item_t *ci) /* {{{ */
249 {
250 int i;
252 for (i = 0; i < ci->children_num; i++)
253 {
254 oconfig_item_t *child = ci->children + i;
255 if ((strcasecmp ("Exec", child->key) == 0)
256 || (strcasecmp ("NagiosExec", child->key) == 0)
257 || (strcasecmp ("NotificationExec", child->key) == 0))
258 exec_config_exec (child);
259 else
260 {
261 WARNING ("exec plugin: Unknown config option `%s'.", child->key);
262 }
263 } /* for (i) */
265 return (0);
266 } /* int exec_config }}} */
268 static void exec_child (program_list_t *pl) /* {{{ */
269 {
270 int status;
271 int uid;
272 int gid;
273 int egid;
275 struct passwd *sp_ptr;
276 struct passwd sp;
277 char nambuf[2048];
278 char errbuf[1024];
280 sp_ptr = NULL;
281 status = getpwnam_r (pl->user, &sp, nambuf, sizeof (nambuf), &sp_ptr);
282 if (status != 0)
283 {
284 ERROR ("exec plugin: getpwnam_r failed: %s",
285 sstrerror (errno, errbuf, sizeof (errbuf)));
286 exit (-1);
287 }
288 if (sp_ptr == NULL)
289 {
290 ERROR ("exec plugin: No such user: `%s'", pl->user);
291 exit (-1);
292 }
294 uid = sp.pw_uid;
295 gid = sp.pw_gid;
296 if (uid == 0)
297 {
298 ERROR ("exec plugin: Cowardly refusing to exec program as root.");
299 exit (-1);
300 }
302 /* The group configured in the configfile is set as effective group, because
303 * this way the forked process can (re-)gain the user's primary group. */
304 egid = -1;
305 if (NULL != pl->group)
306 {
307 if ('\0' != *pl->group) {
308 struct group *gr_ptr = NULL;
309 struct group gr;
311 status = getgrnam_r (pl->group, &gr, nambuf, sizeof (nambuf), &gr_ptr);
312 if (0 != status)
313 {
314 ERROR ("exec plugin: getgrnam_r failed: %s",
315 sstrerror (errno, errbuf, sizeof (errbuf)));
316 exit (-1);
317 }
318 if (NULL == gr_ptr)
319 {
320 ERROR ("exec plugin: No such group: `%s'", pl->group);
321 exit (-1);
322 }
324 egid = gr.gr_gid;
325 }
326 else
327 {
328 egid = gid;
329 }
330 } /* if (pl->group == NULL) */
332 status = setgid (gid);
333 if (status != 0)
334 {
335 ERROR ("exec plugin: setgid (%i) failed: %s",
336 gid, sstrerror (errno, errbuf, sizeof (errbuf)));
337 exit (-1);
338 }
340 if (egid != -1)
341 {
342 status = setegid (egid);
343 if (status != 0)
344 {
345 ERROR ("exec plugin: setegid (%i) failed: %s",
346 egid, sstrerror (errno, errbuf, sizeof (errbuf)));
347 exit (-1);
348 }
349 }
351 status = setuid (uid);
352 if (status != 0)
353 {
354 ERROR ("exec plugin: setuid (%i) failed: %s",
355 uid, sstrerror (errno, errbuf, sizeof (errbuf)));
356 exit (-1);
357 }
359 status = execvp (pl->exec, pl->argv);
361 ERROR ("exec plugin: exec failed: %s",
362 sstrerror (errno, errbuf, sizeof (errbuf)));
363 exit (-1);
364 } /* void exec_child }}} */
366 /*
367 * Creates two pipes (one for reading, ong for writing), forks a child, sets up
368 * the pipes so that fd_in is connected to STDIN of the child and fd_out is
369 * connected to STDOUT and STDERR of the child. Then is calls `exec_child'.
370 */
371 static int fork_child (program_list_t *pl, int *fd_in, int *fd_out) /* {{{ */
372 {
373 int fd_pipe_in[2];
374 int fd_pipe_out[2];
375 int status;
376 int pid;
378 if (pl->pid != 0)
379 return (-1);
381 status = pipe (fd_pipe_in);
382 if (status != 0)
383 {
384 char errbuf[1024];
385 ERROR ("exec plugin: pipe failed: %s",
386 sstrerror (errno, errbuf, sizeof (errbuf)));
387 return (-1);
388 }
390 status = pipe (fd_pipe_out);
391 if (status != 0)
392 {
393 char errbuf[1024];
394 ERROR ("exec plugin: pipe failed: %s",
395 sstrerror (errno, errbuf, sizeof (errbuf)));
396 return (-1);
397 }
399 pid = fork ();
400 if (pid < 0)
401 {
402 char errbuf[1024];
403 ERROR ("exec plugin: fork failed: %s",
404 sstrerror (errno, errbuf, sizeof (errbuf)));
405 return (-1);
406 }
407 else if (pid == 0)
408 {
409 close (fd_pipe_in[1]);
410 close (fd_pipe_out[0]);
412 /* If the `out' pipe has the filedescriptor STDIN we have to be careful
413 * with the `dup's below. So, if this is the case we have to handle the
414 * `out' pipe first. */
415 if (fd_pipe_out[1] == STDIN_FILENO)
416 {
417 int new_fileno = (fd_pipe_in[0] == STDOUT_FILENO)
418 ? STDERR_FILENO : STDOUT_FILENO;
419 dup2 (fd_pipe_out[1], new_fileno);
420 close (fd_pipe_out[1]);
421 fd_pipe_out[1] = new_fileno;
422 }
423 /* Now `fd_pipe_out[1]' is either `STDOUT' or `STDERR', but definitely not
424 * `STDIN_FILENO'. */
426 /* Connect the `in' pipe to STDIN */
427 if (fd_pipe_in[0] != STDIN_FILENO)
428 {
429 dup2 (fd_pipe_in[0], STDIN_FILENO);
430 close (fd_pipe_in[0]);
431 fd_pipe_in[0] = STDIN_FILENO;
432 }
434 /* Now connect the `out' pipe to STDOUT and STDERR */
435 if (fd_pipe_out[1] != STDOUT_FILENO)
436 dup2 (fd_pipe_out[1], STDOUT_FILENO);
437 if (fd_pipe_out[1] != STDERR_FILENO)
438 dup2 (fd_pipe_out[1], STDERR_FILENO);
440 /* If the pipe has some FD that's something completely different, close it
441 * now. */
442 if ((fd_pipe_out[1] != STDOUT_FILENO) && (fd_pipe_out[1] != STDERR_FILENO))
443 {
444 close (fd_pipe_out[1]);
445 fd_pipe_out[1] = STDOUT_FILENO;
446 }
448 exec_child (pl);
449 /* does not return */
450 }
452 close (fd_pipe_in[0]);
453 close (fd_pipe_out[1]);
455 if (fd_in != NULL)
456 *fd_in = fd_pipe_in[1];
457 else
458 close (fd_pipe_in[1]);
460 if (fd_out != NULL)
461 *fd_out = fd_pipe_out[0];
462 else
463 close (fd_pipe_out[0]);
465 return (pid);
466 } /* int fork_child }}} */
468 static int parse_line (char *buffer) /* {{{ */
469 {
470 char *fields[256];
471 int fields_num;
473 fields[0] = "PUTVAL";
474 fields_num = strsplit (buffer, fields + 1, STATIC_ARRAY_SIZE(fields) - 1);
476 if (strcasecmp (fields[1], "putval") == 0)
477 return (handle_putval (stdout, fields + 1, fields_num));
478 else if (strcasecmp (fields[1], "putnotif") == 0)
479 return (handle_putnotif (stdout, fields + 1, fields_num));
481 /* compatibility code */
482 return (handle_putval (stdout, fields, fields_num + 1));
483 } /* int parse_line }}} */
485 static void *exec_read_one (void *arg) /* {{{ */
486 {
487 program_list_t *pl = (program_list_t *) arg;
488 int fd;
489 FILE *fh;
490 char buffer[1024];
491 int status;
493 status = fork_child (pl, NULL, &fd);
494 if (status < 0)
495 pthread_exit ((void *) 1);
496 pl->pid = status;
498 assert (pl->pid != 0);
500 fh = fdopen (fd, "r");
501 if (fh == NULL)
502 {
503 char errbuf[1024];
504 ERROR ("exec plugin: fdopen (%i) failed: %s", fd,
505 sstrerror (errno, errbuf, sizeof (errbuf)));
506 kill (pl->pid, SIGTERM);
507 pl->pid = 0;
508 close (fd);
509 pthread_exit ((void *) 1);
510 }
512 buffer[0] = '\0';
513 while (fgets (buffer, sizeof (buffer), fh) != NULL)
514 {
515 int len;
517 len = strlen (buffer);
519 /* Remove newline from end. */
520 while ((len > 0) && ((buffer[len - 1] == '\n')
521 || (buffer[len - 1] == '\r')))
522 buffer[--len] = '\0';
524 DEBUG ("exec plugin: exec_read_one: buffer = %s", buffer);
526 if (pl->flags & PL_NAGIOS_PLUGIN)
527 break;
529 parse_line (buffer);
530 } /* while (fgets) */
532 fclose (fh);
534 if (waitpid (pl->pid, &status, 0) > 0)
535 pl->status = status;
537 DEBUG ("exec plugin: Child %i exited with status %i.",
538 (int) pl->pid, pl->status);
540 if (pl->flags & PL_NAGIOS_PLUGIN)
541 {
542 notification_t n;
544 memset (&n, '\0', sizeof (n));
546 n.severity = NOTIF_FAILURE;
547 if (pl->status == 0)
548 n.severity = NOTIF_OKAY;
549 else if (pl->status == 1)
550 n.severity = NOTIF_WARNING;
552 strncpy (n.message, buffer, sizeof (n.message));
553 n.message[sizeof (n.message) - 1] = '\0';
555 n.time = time (NULL);
557 strncpy (n.host, hostname_g, sizeof (n.host));
558 n.host[sizeof (n.host) - 1] = '\0';
560 plugin_dispatch_notification (&n);
561 }
563 pl->pid = 0;
565 pthread_mutex_lock (&pl_lock);
566 pl->flags &= ~PL_RUNNING;
567 pthread_mutex_unlock (&pl_lock);
569 pthread_exit ((void *) 0);
570 return (NULL);
571 } /* void *exec_read_one }}} */
573 static void *exec_notification_one (void *arg) /* {{{ */
574 {
575 program_list_t *pl = ((program_list_and_notification_t *) arg)->pl;
576 const notification_t *n = &((program_list_and_notification_t *) arg)->n;
577 int fd;
578 FILE *fh;
579 int pid;
580 int status;
581 const char *severity;
583 pid = fork_child (pl, &fd, NULL);
584 if (pid < 0)
585 pthread_exit ((void *) 1);
587 fh = fdopen (fd, "w");
588 if (fh == NULL)
589 {
590 char errbuf[1024];
591 ERROR ("exec plugin: fdopen (%i) failed: %s", fd,
592 sstrerror (errno, errbuf, sizeof (errbuf)));
593 kill (pl->pid, SIGTERM);
594 pl->pid = 0;
595 close (fd);
596 pthread_exit ((void *) 1);
597 }
599 severity = "FAILURE";
600 if (n->severity == NOTIF_WARNING)
601 severity = "WARNING";
602 else if (n->severity == NOTIF_OKAY)
603 severity = "OKAY";
605 fprintf (fh, "Severity: %s\n"
606 "Time: %u\n"
607 "Message: %s\n",
608 severity, (unsigned int) n->time, n->message);
610 /* Print the optional fields */
611 if (strlen (n->host) > 0)
612 fprintf (fh, "Host: %s\n", n->host);
613 if (strlen (n->plugin) > 0)
614 fprintf (fh, "Plugin: %s\n", n->plugin);
615 if (strlen (n->plugin_instance) > 0)
616 fprintf (fh, "PluginInstance: %s\n", n->plugin_instance);
617 if (strlen (n->type) > 0)
618 fprintf (fh, "Type: %s\n", n->type);
619 if (strlen (n->type_instance) > 0)
620 fprintf (fh, "TypeInstance: %s\n", n->type_instance);
622 /* Newline signalling end of data */
623 fprintf (fh, "\n");
625 fflush (fh);
626 fclose (fh);
628 waitpid (pid, &status, 0);
630 DEBUG ("exec plugin: Child %i exited with status %i.",
631 pid, status);
633 sfree (arg);
634 pthread_exit ((void *) 0);
635 return (NULL);
636 } /* void *exec_notification_one }}} */
638 static int exec_init (void) /* {{{ */
639 {
640 struct sigaction sa;
642 memset (&sa, '\0', sizeof (sa));
643 sa.sa_handler = sigchld_handler;
644 sigaction (SIGCHLD, &sa, NULL);
646 return (0);
647 } /* int exec_init }}} */
649 static int exec_read (void) /* {{{ */
650 {
651 program_list_t *pl;
653 for (pl = pl_head; pl != NULL; pl = pl->next)
654 {
655 pthread_t t;
656 pthread_attr_t attr;
658 /* Only execute `normal' and `nagios' style executables here. */
659 if ((pl->flags & (PL_NAGIOS_PLUGIN | PL_NORMAL)) == 0)
660 continue;
662 pthread_mutex_lock (&pl_lock);
663 /* Skip if a child is already running. */
664 if ((pl->flags & PL_RUNNING) != 0)
665 {
666 pthread_mutex_unlock (&pl_lock);
667 continue;
668 }
669 pl->flags |= PL_RUNNING;
670 pthread_mutex_unlock (&pl_lock);
672 pthread_attr_init (&attr);
673 pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
674 pthread_create (&t, &attr, exec_read_one, (void *) pl);
675 } /* for (pl) */
677 return (0);
678 } /* int exec_read }}} */
680 static int exec_notification (const notification_t *n)
681 {
682 program_list_t *pl;
683 program_list_and_notification_t *pln;
685 for (pl = pl_head; pl != NULL; pl = pl->next)
686 {
687 pthread_t t;
688 pthread_attr_t attr;
690 /* Only execute `notification' style executables here. */
691 if ((pl->flags & PL_NOTIF_ACTION) == 0)
692 continue;
694 /* Skip if a child is already running. */
695 if (pl->pid != 0)
696 continue;
698 pln = (program_list_and_notification_t *) malloc (sizeof
699 (program_list_and_notification_t));
700 if (pln == NULL)
701 {
702 ERROR ("exec plugin: malloc failed.");
703 continue;
704 }
706 pln->pl = pl;
707 memcpy (&pln->n, n, sizeof (notification_t));
709 pthread_attr_init (&attr);
710 pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
711 pthread_create (&t, &attr, exec_notification_one, (void *) pln);
712 } /* for (pl) */
714 return (0);
715 } /* int exec_notification */
717 static int exec_shutdown (void) /* {{{ */
718 {
719 program_list_t *pl;
720 program_list_t *next;
722 pl = pl_head;
723 while (pl != NULL)
724 {
725 next = pl->next;
727 if (pl->pid > 0)
728 {
729 kill (pl->pid, SIGTERM);
730 INFO ("exec plugin: Sent SIGTERM to %hu", (unsigned short int) pl->pid);
731 }
733 sfree (pl->user);
734 sfree (pl);
736 pl = next;
737 } /* while (pl) */
738 pl_head = NULL;
740 return (0);
741 } /* int exec_shutdown }}} */
743 void module_register (void)
744 {
745 plugin_register_complex_config ("exec", exec_config);
746 plugin_register_init ("exec", exec_init);
747 plugin_register_read ("exec", exec_read);
748 plugin_register_notification ("exec", exec_notification);
749 plugin_register_shutdown ("exec", exec_shutdown);
750 } /* void module_register */
752 /*
753 * vim:shiftwidth=2:softtabstop=2:tabstop=8:fdm=marker
754 */