2 * collectd - src/exec.c
3 * Copyright (C) 2007-2010 Florian octo Forster
4 * Copyright (C) 2007-2009 Sebastian Harl
5 * Copyright (C) 2008 Peter Holik
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation; only version 2 of the License is applicable.
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
16 * You should have received a copy of the GNU General Public License along
17 * with this program; if not, write to the Free Software Foundation, Inc.,
18 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
21 * Florian octo Forster <octo at collectd.org>
22 * Sebastian Harl <sh at tokkee.org>
23 * Peter Holik <peter at holik.at>
26 #define _DEFAULT_SOURCE
27 #define _BSD_SOURCE /* For setgroups */
34 #include "utils_cmd_putval.h"
35 #include "utils_cmd_putnotif.h"
37 #include <sys/types.h>
42 #ifdef HAVE_SYS_CAPABILITY_H
43 # include <sys/capability.h>
46 #define PL_NORMAL 0x01
47 #define PL_NOTIF_ACTION 0x02
49 #define PL_RUNNING 0x10
55 * Access to this structure is serialized using the `pl_lock' lock and the
56 * `PL_RUNNING' flag. The execution of notifications is *not* serialized, so
57 * all functions used to handle notifications MUST NOT write to this structure.
58 * The `pid' and `status' fields are thus unused if the `PL_NOTIF_ACTION' flag
60 * The `PL_RUNNING' flag is set in `exec_read' and unset in `exec_read_one'.
62 struct program_list_s;
63 typedef struct program_list_s program_list_t;
76 typedef struct program_list_and_notification_s
80 } program_list_and_notification_t;
85 static program_list_t *pl_head = NULL;
86 static pthread_mutex_t pl_lock = PTHREAD_MUTEX_INITIALIZER;
91 static void sigchld_handler (int __attribute__((unused)) signal) /* {{{ */
95 while ((pid = waitpid (-1, &status, WNOHANG)) > 0)
98 for (pl = pl_head; pl != NULL; pl = pl->next)
103 } /* while (waitpid) */
104 } /* void sigchld_handler }}} */
106 static int exec_config_exec (oconfig_item_t *ci) /* {{{ */
112 if (ci->children_num != 0)
114 WARNING ("exec plugin: The config option `%s' may not be a block.",
118 if (ci->values_num < 2)
120 WARNING ("exec plugin: The config option `%s' needs at least two "
121 "arguments.", ci->key);
124 if ((ci->values[0].type != OCONFIG_TYPE_STRING)
125 || (ci->values[1].type != OCONFIG_TYPE_STRING))
127 WARNING ("exec plugin: The first two arguments to the `%s' option must "
128 "be string arguments.", ci->key);
132 pl = calloc (1, sizeof (*pl));
135 ERROR ("exec plugin: calloc failed.");
139 if (strcasecmp ("NotificationExec", ci->key) == 0)
140 pl->flags |= PL_NOTIF_ACTION;
142 pl->flags |= PL_NORMAL;
144 pl->user = strdup (ci->values[0].value.string);
145 if (pl->user == NULL)
147 ERROR ("exec plugin: strdup failed.");
152 pl->group = strchr (pl->user, ':');
153 if (pl->group != NULL)
159 pl->exec = strdup (ci->values[1].value.string);
160 if (pl->exec == NULL)
162 ERROR ("exec plugin: strdup failed.");
168 pl->argv = calloc (ci->values_num, sizeof (*pl->argv));
169 if (pl->argv == NULL)
171 ERROR ("exec plugin: calloc failed.");
179 char *tmp = strrchr (ci->values[1].value.string, '/');
181 sstrncpy (buffer, ci->values[1].value.string, sizeof (buffer));
183 sstrncpy (buffer, tmp + 1, sizeof (buffer));
185 pl->argv[0] = strdup (buffer);
186 if (pl->argv[0] == NULL)
188 ERROR ("exec plugin: strdup failed.");
196 for (i = 1; i < (ci->values_num - 1); i++)
198 if (ci->values[i + 1].type == OCONFIG_TYPE_STRING)
200 pl->argv[i] = strdup (ci->values[i + 1].value.string);
204 if (ci->values[i + 1].type == OCONFIG_TYPE_NUMBER)
206 ssnprintf (buffer, sizeof (buffer), "%lf",
207 ci->values[i + 1].value.number);
211 if (ci->values[i + 1].value.boolean)
212 sstrncpy (buffer, "true", sizeof (buffer));
214 sstrncpy (buffer, "false", sizeof (buffer));
217 pl->argv[i] = strdup (buffer);
220 if (pl->argv[i] == NULL)
222 ERROR ("exec plugin: strdup failed.");
227 if (i < (ci->values_num - 1))
240 for (i = 0; pl->argv[i] != NULL; i++)
242 DEBUG ("exec plugin: argv[%i] = %s", i, pl->argv[i]);
249 } /* int exec_config_exec }}} */
251 static int exec_config (oconfig_item_t *ci) /* {{{ */
253 for (int i = 0; i < ci->children_num; i++)
255 oconfig_item_t *child = ci->children + i;
256 if ((strcasecmp ("Exec", child->key) == 0)
257 || (strcasecmp ("NotificationExec", child->key) == 0))
258 exec_config_exec (child);
261 WARNING ("exec plugin: Unknown config option `%s'.", child->key);
266 } /* int exec_config }}} */
268 static void set_environment (void) /* {{{ */
273 ssnprintf (buffer, sizeof (buffer), "%.3f",
274 CDTIME_T_TO_DOUBLE (plugin_get_interval ()));
275 setenv ("COLLECTD_INTERVAL", buffer, /* overwrite = */ 1);
277 ssnprintf (buffer, sizeof (buffer), "%s", hostname_g);
278 setenv ("COLLECTD_HOSTNAME", buffer, /* overwrite = */ 1);
280 ssnprintf (buffer, sizeof (buffer), "COLLECTD_INTERVAL=%.3f",
281 CDTIME_T_TO_DOUBLE (plugin_get_interval ()));
284 ssnprintf (buffer, sizeof (buffer), "COLLECTD_HOSTNAME=%s", hostname_g);
287 } /* }}} void set_environment */
289 __attribute__((noreturn))
290 static void exec_child (program_list_t *pl, int uid, int gid, int egid) /* {{{ */
304 if ((gid != egid) && (egid != -1))
310 setgroups (glist_len, glist);
312 #endif /* HAVE_SETGROUPS */
314 status = setgid (gid);
317 ERROR ("exec plugin: setgid (%i) failed: %s",
318 gid, sstrerror (errno, errbuf, sizeof (errbuf)));
324 status = setegid (egid);
327 ERROR ("exec plugin: setegid (%i) failed: %s",
328 egid, sstrerror (errno, errbuf, sizeof (errbuf)));
333 status = setuid (uid);
336 ERROR ("exec plugin: setuid (%i) failed: %s",
337 uid, sstrerror (errno, errbuf, sizeof (errbuf)));
341 execvp (pl->exec, pl->argv);
343 ERROR ("exec plugin: Failed to execute ``%s'': %s",
344 pl->exec, sstrerror (errno, errbuf, sizeof (errbuf)));
346 } /* void exec_child }}} */
348 static void reset_signal_mask (void) /* {{{ */
353 sigprocmask (SIG_SETMASK, &ss, /* old mask = */ NULL);
354 } /* }}} void reset_signal_mask */
356 static int create_pipe (int fd_pipe[2]) /* {{{ */
361 status = pipe (fd_pipe);
364 ERROR ("exec plugin: pipe failed: %s",
365 sstrerror (errno, errbuf, sizeof (errbuf)));
370 } /* }}} int create_pipe */
372 static void close_pipe (int fd_pipe[2]) /* {{{ */
374 if (fd_pipe[0] != -1)
377 if (fd_pipe[1] != -1)
379 } /* }}} void close_pipe */
382 * Creates three pipes (one for reading, one for writing and one for errors),
383 * forks a child, sets up the pipes so that fd_in is connected to STDIN of
384 * the child and fd_out is connected to STDOUT and fd_err is connected to STDERR
385 * of the child. Then is calls `exec_child'.
387 static int fork_child (program_list_t *pl, int *fd_in, int *fd_out, int *fd_err) /* {{{ */
389 int fd_pipe_in[2] = {-1, -1};
390 int fd_pipe_out[2] = {-1, -1};
391 int fd_pipe_err[2] = {-1, -1};
400 struct passwd *sp_ptr;
407 if ((create_pipe(fd_pipe_in) == -1)
408 || (create_pipe(fd_pipe_out) == -1)
409 || (create_pipe(fd_pipe_err) == -1))
413 status = getpwnam_r (pl->user, &sp, nambuf, sizeof (nambuf), &sp_ptr);
416 ERROR ("exec plugin: Failed to get user information for user ``%s'': %s",
417 pl->user, sstrerror (errno, errbuf, sizeof (errbuf)));
423 ERROR ("exec plugin: No such user: `%s'", pl->user);
431 ERROR ("exec plugin: Cowardly refusing to exec program as root.");
435 /* The group configured in the configfile is set as effective group, because
436 * this way the forked process can (re-)gain the user's primary group. */
438 if (NULL != pl->group)
440 if ('\0' != *pl->group) {
441 struct group *gr_ptr = NULL;
444 status = getgrnam_r (pl->group, &gr, nambuf, sizeof (nambuf), &gr_ptr);
447 ERROR ("exec plugin: Failed to get group information "
448 "for group ``%s'': %s", pl->group,
449 sstrerror (errno, errbuf, sizeof (errbuf)));
454 ERROR ("exec plugin: No such group: `%s'", pl->group);
464 } /* if (pl->group == NULL) */
469 ERROR ("exec plugin: fork failed: %s",
470 sstrerror (errno, errbuf, sizeof (errbuf)));
477 /* Close all file descriptors but the pipe end we need. */
478 fd_num = getdtablesize ();
479 for (int fd = 0; fd < fd_num; fd++)
481 if ((fd == fd_pipe_in[0])
482 || (fd == fd_pipe_out[1])
483 || (fd == fd_pipe_err[1]))
488 /* Connect the `in' pipe to STDIN */
489 if (fd_pipe_in[0] != STDIN_FILENO)
491 dup2 (fd_pipe_in[0], STDIN_FILENO);
492 close (fd_pipe_in[0]);
495 /* Now connect the `out' pipe to STDOUT */
496 if (fd_pipe_out[1] != STDOUT_FILENO)
498 dup2 (fd_pipe_out[1], STDOUT_FILENO);
499 close (fd_pipe_out[1]);
502 /* Now connect the `err' pipe to STDERR */
503 if (fd_pipe_err[1] != STDERR_FILENO)
505 dup2 (fd_pipe_err[1], STDERR_FILENO);
506 close (fd_pipe_err[1]);
511 /* Unblock all signals */
512 reset_signal_mask ();
514 exec_child (pl, uid, gid, egid);
515 /* does not return */
518 close (fd_pipe_in[0]);
519 close (fd_pipe_out[1]);
520 close (fd_pipe_err[1]);
523 *fd_in = fd_pipe_in[1];
525 close (fd_pipe_in[1]);
528 *fd_out = fd_pipe_out[0];
530 close (fd_pipe_out[0]);
533 *fd_err = fd_pipe_err[0];
535 close (fd_pipe_err[0]);
540 close_pipe(fd_pipe_in);
541 close_pipe(fd_pipe_out);
542 close_pipe(fd_pipe_err);
545 } /* int fork_child }}} */
547 static int parse_line (char *buffer) /* {{{ */
549 if (strncasecmp ("PUTVAL", buffer, strlen ("PUTVAL")) == 0)
550 return (cmd_handle_putval (stdout, buffer));
551 else if (strncasecmp ("PUTNOTIF", buffer, strlen ("PUTNOTIF")) == 0)
552 return (handle_putnotif (stdout, buffer));
555 ERROR ("exec plugin: Unable to parse command, ignoring line: \"%s\"",
559 } /* int parse_line }}} */
561 static void *exec_read_one (void *arg) /* {{{ */
563 program_list_t *pl = (program_list_t *) arg;
564 int fd, fd_err, highest_fd;
567 char buffer[1200]; /* if not completely read */
568 char buffer_err[1024];
569 char *pbuffer = buffer;
570 char *pbuffer_err = buffer_err;
572 status = fork_child (pl, NULL, &fd, &fd_err);
575 /* Reset the "running" flag */
576 pthread_mutex_lock (&pl_lock);
577 pl->flags &= ~PL_RUNNING;
578 pthread_mutex_unlock (&pl_lock);
579 pthread_exit ((void *) 1);
583 assert (pl->pid != 0);
587 FD_SET(fd_err, &fdset);
589 /* Determine the highest file descriptor */
590 highest_fd = (fd > fd_err) ? fd : fd_err;
592 /* We use a copy of fdset, as select modifies it */
599 status = select (highest_fd + 1, ©, NULL, NULL, NULL);
607 if (FD_ISSET(fd, ©))
611 len = read(fd, pbuffer, sizeof(buffer) - 1 - (pbuffer - buffer));
615 if (errno == EAGAIN || errno == EINTR) continue;
618 else if (len == 0) break; /* We've reached EOF */
622 len += pbuffer - buffer;
625 while ((pnl = strchr(pbuffer, '\n')))
628 if (*(pnl-1) == '\r' ) *(pnl-1) = '\0';
630 parse_line (pbuffer);
634 /* not completely read ? */
635 if (pbuffer - buffer < len)
637 len -= pbuffer - buffer;
638 memmove(buffer, pbuffer, len);
639 pbuffer = buffer + len;
644 else if (FD_ISSET(fd_err, ©))
648 len = read(fd_err, pbuffer_err, sizeof(buffer_err) - 1 - (pbuffer_err - buffer_err));
652 if (errno == EAGAIN || errno == EINTR)
658 /* We've reached EOF */
659 NOTICE ("exec plugin: Program `%s' has closed STDERR.", pl->exec);
661 /* Remove file descriptor form select() set. */
662 FD_CLR (fd_err, &fdset);
666 /* Clean up file descriptor */
672 pbuffer_err[len] = '\0';
674 len += pbuffer_err - buffer_err;
675 pbuffer_err = buffer_err;
677 while ((pnl = strchr(pbuffer_err, '\n')))
680 if (*(pnl-1) == '\r' ) *(pnl-1) = '\0';
682 ERROR ("exec plugin: exec_read_one: error = %s", pbuffer_err);
686 /* not completely read ? */
687 if (pbuffer_err - buffer_err < len)
689 len -= pbuffer_err - buffer_err;
690 memmove(buffer_err, pbuffer_err, len);
691 pbuffer_err = buffer_err + len;
694 pbuffer_err = buffer_err;
700 DEBUG ("exec plugin: exec_read_one: Waiting for `%s' to exit.", pl->exec);
701 if (waitpid (pl->pid, &status, 0) > 0)
704 DEBUG ("exec plugin: Child %i exited with status %i.",
705 (int) pl->pid, pl->status);
709 pthread_mutex_lock (&pl_lock);
710 pl->flags &= ~PL_RUNNING;
711 pthread_mutex_unlock (&pl_lock);
717 pthread_exit ((void *) 0);
719 } /* void *exec_read_one }}} */
721 static void *exec_notification_one (void *arg) /* {{{ */
723 program_list_t *pl = ((program_list_and_notification_t *) arg)->pl;
724 notification_t *n = &((program_list_and_notification_t *) arg)->n;
729 const char *severity;
731 pid = fork_child (pl, &fd, NULL, NULL);
734 pthread_exit ((void *) 1);
737 fh = fdopen (fd, "w");
741 ERROR ("exec plugin: fdopen (%i) failed: %s", fd,
742 sstrerror (errno, errbuf, sizeof (errbuf)));
746 pthread_exit ((void *) 1);
749 severity = "FAILURE";
750 if (n->severity == NOTIF_WARNING)
751 severity = "WARNING";
752 else if (n->severity == NOTIF_OKAY)
758 severity, CDTIME_T_TO_DOUBLE (n->time));
760 /* Print the optional fields */
761 if (strlen (n->host) > 0)
762 fprintf (fh, "Host: %s\n", n->host);
763 if (strlen (n->plugin) > 0)
764 fprintf (fh, "Plugin: %s\n", n->plugin);
765 if (strlen (n->plugin_instance) > 0)
766 fprintf (fh, "PluginInstance: %s\n", n->plugin_instance);
767 if (strlen (n->type) > 0)
768 fprintf (fh, "Type: %s\n", n->type);
769 if (strlen (n->type_instance) > 0)
770 fprintf (fh, "TypeInstance: %s\n", n->type_instance);
772 for (notification_meta_t *meta = n->meta; meta != NULL; meta = meta->next)
774 if (meta->type == NM_TYPE_STRING)
775 fprintf (fh, "%s: %s\n", meta->name, meta->nm_value.nm_string);
776 else if (meta->type == NM_TYPE_SIGNED_INT)
777 fprintf (fh, "%s: %"PRIi64"\n", meta->name, meta->nm_value.nm_signed_int);
778 else if (meta->type == NM_TYPE_UNSIGNED_INT)
779 fprintf (fh, "%s: %"PRIu64"\n", meta->name, meta->nm_value.nm_unsigned_int);
780 else if (meta->type == NM_TYPE_DOUBLE)
781 fprintf (fh, "%s: %e\n", meta->name, meta->nm_value.nm_double);
782 else if (meta->type == NM_TYPE_BOOLEAN)
783 fprintf (fh, "%s: %s\n", meta->name,
784 meta->nm_value.nm_boolean ? "true" : "false");
787 fprintf (fh, "\n%s\n", n->message);
792 waitpid (pid, &status, 0);
794 DEBUG ("exec plugin: Child %i exited with status %i.",
798 plugin_notification_meta_free (n->meta);
801 pthread_exit ((void *) 0);
803 } /* void *exec_notification_one }}} */
805 static int exec_init (void) /* {{{ */
807 struct sigaction sa = {
808 .sa_handler = sigchld_handler
811 sigaction (SIGCHLD, &sa, NULL);
813 #if defined(HAVE_SYS_CAPABILITY_H) && defined(CAP_SETUID) && defined(CAP_SETGID)
814 if ((check_capability (CAP_SETUID) != 0) ||
815 (check_capability (CAP_SETGID) != 0))
818 WARNING ("exec plugin: Running collectd as root, but the CAP_SETUID "
819 "or CAP_SETGID capabilities are missing. The plugin's read function "
820 "will probably fail. Is your init system dropping capabilities?");
822 WARNING ("exec plugin: collectd doesn't have the CAP_SETUID or "
823 "CAP_SETGID capabilities. If you don't want to run collectd as root, "
824 "try running \"setcap 'cap_setuid=ep cap_setgid=ep'\" on the "
830 } /* int exec_init }}} */
832 static int exec_read (void) /* {{{ */
834 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next)
839 /* Only execute `normal' style executables here. */
840 if ((pl->flags & PL_NORMAL) == 0)
843 pthread_mutex_lock (&pl_lock);
844 /* Skip if a child is already running. */
845 if ((pl->flags & PL_RUNNING) != 0)
847 pthread_mutex_unlock (&pl_lock);
850 pl->flags |= PL_RUNNING;
851 pthread_mutex_unlock (&pl_lock);
853 pthread_attr_init (&attr);
854 pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
855 plugin_thread_create (&t, &attr, exec_read_one, (void *) pl);
856 pthread_attr_destroy (&attr);
860 } /* int exec_read }}} */
862 static int exec_notification (const notification_t *n, /* {{{ */
863 user_data_t __attribute__((unused)) *user_data)
865 program_list_and_notification_t *pln;
867 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next)
872 /* Only execute `notification' style executables here. */
873 if ((pl->flags & PL_NOTIF_ACTION) == 0)
876 /* Skip if a child is already running. */
880 pln = malloc (sizeof (*pln));
883 ERROR ("exec plugin: malloc failed.");
888 memcpy (&pln->n, n, sizeof (notification_t));
890 /* Set the `meta' member to NULL, otherwise `plugin_notification_meta_copy'
891 * will run into an endless loop. */
893 plugin_notification_meta_copy (&pln->n, n);
895 pthread_attr_init (&attr);
896 pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
897 plugin_thread_create (&t, &attr, exec_notification_one, (void *) pln);
898 pthread_attr_destroy (&attr);
902 } /* }}} int exec_notification */
904 static int exec_shutdown (void) /* {{{ */
907 program_list_t *next;
916 kill (pl->pid, SIGTERM);
917 INFO ("exec plugin: Sent SIGTERM to %hu", (unsigned short int) pl->pid);
928 } /* int exec_shutdown }}} */
930 void module_register (void)
932 plugin_register_complex_config ("exec", exec_config);
933 plugin_register_init ("exec", exec_init);
934 plugin_register_read ("exec", exec_read);
935 plugin_register_notification ("exec", exec_notification,
936 /* user_data = */ NULL);
937 plugin_register_shutdown ("exec", exec_shutdown);
938 } /* void module_register */
941 * vim:shiftwidth=2:softtabstop=2:tabstop=8:fdm=marker