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
39 #define PL_RUNNING 0x10
41 /*
42 * Private data types
43 */
44 /*
45 * Access to this structure is serialized using the `pl_lock' lock and the
46 * `PL_RUNNING' flag. The execution of notifications is *not* serialized, so
47 * all functions used to handle notifications MUST NOT write to this structure.
48 * The `pid' and `status' fields are thus unused if the `PL_NOTIF_ACTION' flag
49 * is set.
50 * The `PL_RUNNING' flag is set in `exec_read' and unset in `exec_read_one'.
51 */
52 struct program_list_s;
53 typedef struct program_list_s program_list_t;
54 struct program_list_s
55 {
56 char *user;
57 char *group;
58 char *exec;
59 char **argv;
60 int pid;
61 int status;
62 int flags;
63 program_list_t *next;
64 };
66 typedef struct program_list_and_notification_s
67 {
68 program_list_t *pl;
69 notification_t n;
70 } program_list_and_notification_t;
72 /*
73 * Private variables
74 */
75 static program_list_t *pl_head = NULL;
76 static pthread_mutex_t pl_lock = PTHREAD_MUTEX_INITIALIZER;
78 /*
79 * Functions
80 */
81 static void sigchld_handler (int signal) /* {{{ */
82 {
83 pid_t pid;
84 int status;
85 while ((pid = waitpid (-1, &status, WNOHANG)) > 0)
86 {
87 program_list_t *pl;
88 for (pl = pl_head; pl != NULL; pl = pl->next)
89 if (pl->pid == pid)
90 break;
91 if (pl != NULL)
92 pl->status = status;
93 } /* while (waitpid) */
94 } /* void sigchld_handler }}} */
96 static int exec_config_exec (oconfig_item_t *ci) /* {{{ */
97 {
98 program_list_t *pl;
99 char buffer[128];
100 int i;
102 if (ci->children_num != 0)
103 {
104 WARNING ("exec plugin: The config option `%s' may not be a block.",
105 ci->key);
106 return (-1);
107 }
108 if (ci->values_num < 2)
109 {
110 WARNING ("exec plugin: The config option `%s' needs at least two "
111 "arguments.", ci->key);
112 return (-1);
113 }
114 if ((ci->values[0].type != OCONFIG_TYPE_STRING)
115 || (ci->values[1].type != OCONFIG_TYPE_STRING))
116 {
117 WARNING ("exec plugin: The first two arguments to the `%s' option must "
118 "be string arguments.", ci->key);
119 return (-1);
120 }
122 pl = (program_list_t *) malloc (sizeof (program_list_t));
123 if (pl == NULL)
124 {
125 ERROR ("exec plugin: malloc failed.");
126 return (-1);
127 }
128 memset (pl, '\0', sizeof (program_list_t));
130 if (strcasecmp ("NotificationExec", ci->key) == 0)
131 pl->flags |= PL_NOTIF_ACTION;
132 else
133 pl->flags |= PL_NORMAL;
135 pl->user = strdup (ci->values[0].value.string);
136 if (pl->user == NULL)
137 {
138 ERROR ("exec plugin: strdup failed.");
139 sfree (pl);
140 return (-1);
141 }
143 pl->group = strchr (pl->user, ':');
144 if (pl->group != NULL)
145 {
146 *pl->group = '\0';
147 pl->group++;
148 }
150 pl->exec = strdup (ci->values[1].value.string);
151 if (pl->exec == NULL)
152 {
153 ERROR ("exec plugin: strdup failed.");
154 sfree (pl->user);
155 sfree (pl);
156 return (-1);
157 }
159 pl->argv = (char **) malloc (ci->values_num * sizeof (char *));
160 if (pl->argv == NULL)
161 {
162 ERROR ("exec plugin: malloc failed.");
163 sfree (pl->exec);
164 sfree (pl->user);
165 sfree (pl);
166 return (-1);
167 }
168 memset (pl->argv, '\0', ci->values_num * sizeof (char *));
170 {
171 char *tmp = strrchr (ci->values[1].value.string, '/');
172 if (tmp == NULL)
173 strncpy (buffer, ci->values[1].value.string, sizeof (buffer));
174 else
175 strncpy (buffer, tmp + 1, sizeof (buffer));
176 buffer[sizeof (buffer) - 1] = '\0';
177 }
178 pl->argv[0] = strdup (buffer);
179 if (pl->argv[0] == NULL)
180 {
181 ERROR ("exec plugin: malloc failed.");
182 sfree (pl->argv);
183 sfree (pl->exec);
184 sfree (pl->user);
185 sfree (pl);
186 return (-1);
187 }
189 for (i = 1; i < (ci->values_num - 1); i++)
190 {
191 if (ci->values[i + 1].type == OCONFIG_TYPE_STRING)
192 {
193 pl->argv[i] = strdup (ci->values[i + 1].value.string);
194 }
195 else
196 {
197 if (ci->values[i + 1].type == OCONFIG_TYPE_NUMBER)
198 {
199 snprintf (buffer, sizeof (buffer), "%lf",
200 ci->values[i + 1].value.number);
201 }
202 else
203 {
204 if (ci->values[i + 1].value.boolean)
205 strncpy (buffer, "true", sizeof (buffer));
206 else
207 strncpy (buffer, "false", sizeof (buffer));
208 }
209 buffer[sizeof (buffer) - 1] = '\0';
211 pl->argv[i] = strdup (buffer);
212 }
214 if (pl->argv[i] == NULL)
215 {
216 ERROR ("exec plugin: strdup failed.");
217 break;
218 }
219 } /* for (i) */
221 if (i < (ci->values_num - 1))
222 {
223 while ((--i) >= 0)
224 {
225 sfree (pl->argv[i]);
226 }
227 sfree (pl->argv);
228 sfree (pl->exec);
229 sfree (pl->user);
230 sfree (pl);
231 return (-1);
232 }
234 for (i = 0; pl->argv[i] != NULL; i++)
235 {
236 DEBUG ("exec plugin: argv[%i] = %s", i, pl->argv[i]);
237 }
239 pl->next = pl_head;
240 pl_head = pl;
242 return (0);
243 } /* int exec_config_exec }}} */
245 static int exec_config (oconfig_item_t *ci) /* {{{ */
246 {
247 int i;
249 for (i = 0; i < ci->children_num; i++)
250 {
251 oconfig_item_t *child = ci->children + i;
252 if ((strcasecmp ("Exec", child->key) == 0)
253 || (strcasecmp ("NotificationExec", child->key) == 0))
254 exec_config_exec (child);
255 else
256 {
257 WARNING ("exec plugin: Unknown config option `%s'.", child->key);
258 }
259 } /* for (i) */
261 return (0);
262 } /* int exec_config }}} */
264 static void exec_child (program_list_t *pl) /* {{{ */
265 {
266 int status;
267 int uid;
268 int gid;
269 int egid;
271 struct passwd *sp_ptr;
272 struct passwd sp;
273 char nambuf[2048];
274 char errbuf[1024];
276 sp_ptr = NULL;
277 status = getpwnam_r (pl->user, &sp, nambuf, sizeof (nambuf), &sp_ptr);
278 if (status != 0)
279 {
280 ERROR ("exec plugin: getpwnam_r failed: %s",
281 sstrerror (errno, errbuf, sizeof (errbuf)));
282 exit (-1);
283 }
284 if (sp_ptr == NULL)
285 {
286 ERROR ("exec plugin: No such user: `%s'", pl->user);
287 exit (-1);
288 }
290 uid = sp.pw_uid;
291 gid = sp.pw_gid;
292 if (uid == 0)
293 {
294 ERROR ("exec plugin: Cowardly refusing to exec program as root.");
295 exit (-1);
296 }
298 /* The group configured in the configfile is set as effective group, because
299 * this way the forked process can (re-)gain the user's primary group. */
300 egid = -1;
301 if (NULL != pl->group)
302 {
303 if ('\0' != *pl->group) {
304 struct group *gr_ptr = NULL;
305 struct group gr;
307 status = getgrnam_r (pl->group, &gr, nambuf, sizeof (nambuf), &gr_ptr);
308 if (0 != status)
309 {
310 ERROR ("exec plugin: getgrnam_r failed: %s",
311 sstrerror (errno, errbuf, sizeof (errbuf)));
312 exit (-1);
313 }
314 if (NULL == gr_ptr)
315 {
316 ERROR ("exec plugin: No such group: `%s'", pl->group);
317 exit (-1);
318 }
320 egid = gr.gr_gid;
321 }
322 else
323 {
324 egid = gid;
325 }
326 } /* if (pl->group == NULL) */
328 #if HAVE_SETGROUPS
329 if (getuid () == 0)
330 {
331 gid_t glist[2];
332 size_t glist_len;
334 glist[0] = gid;
335 glist_len = 1;
337 if ((gid != egid) && (egid != -1))
338 {
339 glist[1] = egid;
340 glist_len = 2;
341 }
343 setgroups (glist_len, glist);
344 }
345 #endif /* HAVE_SETGROUPS */
347 status = setgid (gid);
348 if (status != 0)
349 {
350 ERROR ("exec plugin: setgid (%i) failed: %s",
351 gid, sstrerror (errno, errbuf, sizeof (errbuf)));
352 exit (-1);
353 }
355 if (egid != -1)
356 {
357 status = setegid (egid);
358 if (status != 0)
359 {
360 ERROR ("exec plugin: setegid (%i) failed: %s",
361 egid, sstrerror (errno, errbuf, sizeof (errbuf)));
362 exit (-1);
363 }
364 }
366 status = setuid (uid);
367 if (status != 0)
368 {
369 ERROR ("exec plugin: setuid (%i) failed: %s",
370 uid, sstrerror (errno, errbuf, sizeof (errbuf)));
371 exit (-1);
372 }
374 status = execvp (pl->exec, pl->argv);
376 ERROR ("exec plugin: exec failed: %s",
377 sstrerror (errno, errbuf, sizeof (errbuf)));
378 exit (-1);
379 } /* void exec_child }}} */
381 /*
382 * Creates two pipes (one for reading, ong for writing), forks a child, sets up
383 * the pipes so that fd_in is connected to STDIN of the child and fd_out is
384 * connected to STDOUT and STDERR of the child. Then is calls `exec_child'.
385 */
386 static int fork_child (program_list_t *pl, int *fd_in, int *fd_out) /* {{{ */
387 {
388 int fd_pipe_in[2];
389 int fd_pipe_out[2];
390 int status;
391 int pid;
393 if (pl->pid != 0)
394 return (-1);
396 status = pipe (fd_pipe_in);
397 if (status != 0)
398 {
399 char errbuf[1024];
400 ERROR ("exec plugin: pipe failed: %s",
401 sstrerror (errno, errbuf, sizeof (errbuf)));
402 return (-1);
403 }
405 status = pipe (fd_pipe_out);
406 if (status != 0)
407 {
408 char errbuf[1024];
409 ERROR ("exec plugin: pipe failed: %s",
410 sstrerror (errno, errbuf, sizeof (errbuf)));
411 return (-1);
412 }
414 pid = fork ();
415 if (pid < 0)
416 {
417 char errbuf[1024];
418 ERROR ("exec plugin: fork failed: %s",
419 sstrerror (errno, errbuf, sizeof (errbuf)));
420 return (-1);
421 }
422 else if (pid == 0)
423 {
424 close (fd_pipe_in[1]);
425 close (fd_pipe_out[0]);
427 /* If the `out' pipe has the filedescriptor STDIN we have to be careful
428 * with the `dup's below. So, if this is the case we have to handle the
429 * `out' pipe first. */
430 if (fd_pipe_out[1] == STDIN_FILENO)
431 {
432 int new_fileno = (fd_pipe_in[0] == STDOUT_FILENO)
433 ? STDERR_FILENO : STDOUT_FILENO;
434 dup2 (fd_pipe_out[1], new_fileno);
435 close (fd_pipe_out[1]);
436 fd_pipe_out[1] = new_fileno;
437 }
438 /* Now `fd_pipe_out[1]' is either `STDOUT' or `STDERR', but definitely not
439 * `STDIN_FILENO'. */
441 /* Connect the `in' pipe to STDIN */
442 if (fd_pipe_in[0] != STDIN_FILENO)
443 {
444 dup2 (fd_pipe_in[0], STDIN_FILENO);
445 close (fd_pipe_in[0]);
446 fd_pipe_in[0] = STDIN_FILENO;
447 }
449 /* Now connect the `out' pipe to STDOUT and STDERR */
450 if (fd_pipe_out[1] != STDOUT_FILENO)
451 dup2 (fd_pipe_out[1], STDOUT_FILENO);
452 if (fd_pipe_out[1] != STDERR_FILENO)
453 dup2 (fd_pipe_out[1], STDERR_FILENO);
455 /* If the pipe has some FD that's something completely different, close it
456 * now. */
457 if ((fd_pipe_out[1] != STDOUT_FILENO) && (fd_pipe_out[1] != STDERR_FILENO))
458 {
459 close (fd_pipe_out[1]);
460 fd_pipe_out[1] = STDOUT_FILENO;
461 }
463 exec_child (pl);
464 /* does not return */
465 }
467 close (fd_pipe_in[0]);
468 close (fd_pipe_out[1]);
470 if (fd_in != NULL)
471 *fd_in = fd_pipe_in[1];
472 else
473 close (fd_pipe_in[1]);
475 if (fd_out != NULL)
476 *fd_out = fd_pipe_out[0];
477 else
478 close (fd_pipe_out[0]);
480 return (pid);
481 } /* int fork_child }}} */
483 static int parse_line (char *buffer) /* {{{ */
484 {
485 char *fields[256];
486 int fields_num;
488 fields[0] = "PUTVAL";
489 fields_num = strsplit (buffer, fields + 1, STATIC_ARRAY_SIZE(fields) - 1);
491 if (strcasecmp (fields[1], "putval") == 0)
492 return (handle_putval (stdout, fields + 1, fields_num));
493 else if (strcasecmp (fields[1], "putnotif") == 0)
494 return (handle_putnotif (stdout, fields + 1, fields_num));
496 /* compatibility code */
497 return (handle_putval (stdout, fields, fields_num + 1));
498 } /* int parse_line }}} */
500 static void *exec_read_one (void *arg) /* {{{ */
501 {
502 program_list_t *pl = (program_list_t *) arg;
503 int fd;
504 FILE *fh;
505 char buffer[1024];
506 int status;
508 status = fork_child (pl, NULL, &fd);
509 if (status < 0)
510 pthread_exit ((void *) 1);
511 pl->pid = status;
513 assert (pl->pid != 0);
515 fh = fdopen (fd, "r");
516 if (fh == NULL)
517 {
518 char errbuf[1024];
519 ERROR ("exec plugin: fdopen (%i) failed: %s", fd,
520 sstrerror (errno, errbuf, sizeof (errbuf)));
521 kill (pl->pid, SIGTERM);
522 pl->pid = 0;
523 close (fd);
524 pthread_exit ((void *) 1);
525 }
527 buffer[0] = '\0';
528 while (fgets (buffer, sizeof (buffer), fh) != NULL)
529 {
530 int len;
532 len = strlen (buffer);
534 /* Remove newline from end. */
535 while ((len > 0) && ((buffer[len - 1] == '\n')
536 || (buffer[len - 1] == '\r')))
537 buffer[--len] = '\0';
539 DEBUG ("exec plugin: exec_read_one: buffer = %s", buffer);
541 parse_line (buffer);
542 } /* while (fgets) */
544 fclose (fh);
546 if (waitpid (pl->pid, &status, 0) > 0)
547 pl->status = status;
549 DEBUG ("exec plugin: Child %i exited with status %i.",
550 (int) pl->pid, pl->status);
552 pl->pid = 0;
554 pthread_mutex_lock (&pl_lock);
555 pl->flags &= ~PL_RUNNING;
556 pthread_mutex_unlock (&pl_lock);
558 pthread_exit ((void *) 0);
559 return (NULL);
560 } /* void *exec_read_one }}} */
562 static void *exec_notification_one (void *arg) /* {{{ */
563 {
564 program_list_t *pl = ((program_list_and_notification_t *) arg)->pl;
565 const notification_t *n = &((program_list_and_notification_t *) arg)->n;
566 int fd;
567 FILE *fh;
568 int pid;
569 int status;
570 const char *severity;
572 pid = fork_child (pl, &fd, NULL);
573 if (pid < 0) {
574 sfree (arg);
575 pthread_exit ((void *) 1);
576 }
578 fh = fdopen (fd, "w");
579 if (fh == NULL)
580 {
581 char errbuf[1024];
582 ERROR ("exec plugin: fdopen (%i) failed: %s", fd,
583 sstrerror (errno, errbuf, sizeof (errbuf)));
584 kill (pl->pid, SIGTERM);
585 pl->pid = 0;
586 close (fd);
587 sfree (arg);
588 pthread_exit ((void *) 1);
589 }
591 severity = "FAILURE";
592 if (n->severity == NOTIF_WARNING)
593 severity = "WARNING";
594 else if (n->severity == NOTIF_OKAY)
595 severity = "OKAY";
597 fprintf (fh,
598 "Severity: %s\n"
599 "Time: %u\n",
600 severity, (unsigned int) n->time);
602 /* Print the optional fields */
603 if (strlen (n->host) > 0)
604 fprintf (fh, "Host: %s\n", n->host);
605 if (strlen (n->plugin) > 0)
606 fprintf (fh, "Plugin: %s\n", n->plugin);
607 if (strlen (n->plugin_instance) > 0)
608 fprintf (fh, "PluginInstance: %s\n", n->plugin_instance);
609 if (strlen (n->type) > 0)
610 fprintf (fh, "Type: %s\n", n->type);
611 if (strlen (n->type_instance) > 0)
612 fprintf (fh, "TypeInstance: %s\n", n->type_instance);
614 fprintf (fh, "\n%s\n", n->message);
616 fflush (fh);
617 fclose (fh);
619 waitpid (pid, &status, 0);
621 DEBUG ("exec plugin: Child %i exited with status %i.",
622 pid, status);
624 sfree (arg);
625 pthread_exit ((void *) 0);
626 return (NULL);
627 } /* void *exec_notification_one }}} */
629 static int exec_init (void) /* {{{ */
630 {
631 struct sigaction sa;
633 memset (&sa, '\0', sizeof (sa));
634 sa.sa_handler = sigchld_handler;
635 sigaction (SIGCHLD, &sa, NULL);
637 return (0);
638 } /* int exec_init }}} */
640 static int exec_read (void) /* {{{ */
641 {
642 program_list_t *pl;
644 for (pl = pl_head; pl != NULL; pl = pl->next)
645 {
646 pthread_t t;
647 pthread_attr_t attr;
649 /* Only execute `normal' style executables here. */
650 if ((pl->flags & PL_NORMAL) == 0)
651 continue;
653 pthread_mutex_lock (&pl_lock);
654 /* Skip if a child is already running. */
655 if ((pl->flags & PL_RUNNING) != 0)
656 {
657 pthread_mutex_unlock (&pl_lock);
658 continue;
659 }
660 pl->flags |= PL_RUNNING;
661 pthread_mutex_unlock (&pl_lock);
663 pthread_attr_init (&attr);
664 pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
665 pthread_create (&t, &attr, exec_read_one, (void *) pl);
666 } /* for (pl) */
668 return (0);
669 } /* int exec_read }}} */
671 static int exec_notification (const notification_t *n)
672 {
673 program_list_t *pl;
674 program_list_and_notification_t *pln;
676 for (pl = pl_head; pl != NULL; pl = pl->next)
677 {
678 pthread_t t;
679 pthread_attr_t attr;
681 /* Only execute `notification' style executables here. */
682 if ((pl->flags & PL_NOTIF_ACTION) == 0)
683 continue;
685 /* Skip if a child is already running. */
686 if (pl->pid != 0)
687 continue;
689 pln = (program_list_and_notification_t *) malloc (sizeof
690 (program_list_and_notification_t));
691 if (pln == NULL)
692 {
693 ERROR ("exec plugin: malloc failed.");
694 continue;
695 }
697 pln->pl = pl;
698 memcpy (&pln->n, n, sizeof (notification_t));
700 pthread_attr_init (&attr);
701 pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
702 pthread_create (&t, &attr, exec_notification_one, (void *) pln);
703 } /* for (pl) */
705 return (0);
706 } /* int exec_notification */
708 static int exec_shutdown (void) /* {{{ */
709 {
710 program_list_t *pl;
711 program_list_t *next;
713 pl = pl_head;
714 while (pl != NULL)
715 {
716 next = pl->next;
718 if (pl->pid > 0)
719 {
720 kill (pl->pid, SIGTERM);
721 INFO ("exec plugin: Sent SIGTERM to %hu", (unsigned short int) pl->pid);
722 }
724 sfree (pl->user);
725 sfree (pl);
727 pl = next;
728 } /* while (pl) */
729 pl_head = NULL;
731 return (0);
732 } /* int exec_shutdown }}} */
734 void module_register (void)
735 {
736 plugin_register_complex_config ("exec", exec_config);
737 plugin_register_init ("exec", exec_init);
738 plugin_register_read ("exec", exec_read);
739 plugin_register_notification ("exec", exec_notification);
740 plugin_register_shutdown ("exec", exec_shutdown);
741 } /* void module_register */
743 /*
744 * vim:shiftwidth=2:softtabstop=2:tabstop=8:fdm=marker
745 */