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_putnotif.h"
35 #include "utils_cmd_putval.h"
40 #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;
64 struct program_list_s {
75 typedef struct program_list_and_notification_s {
78 } program_list_and_notification_t;
83 static program_list_t *pl_head = NULL;
84 static pthread_mutex_t pl_lock = PTHREAD_MUTEX_INITIALIZER;
89 static void sigchld_handler(int __attribute__((unused)) signal) /* {{{ */
93 while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
95 for (pl = pl_head; pl != NULL; pl = pl->next)
100 } /* while (waitpid) */
101 } /* void sigchld_handler }}} */
103 static int exec_config_exec(oconfig_item_t *ci) /* {{{ */
109 if (ci->children_num != 0) {
110 WARNING("exec plugin: The config option `%s' may not be a block.", ci->key);
113 if (ci->values_num < 2) {
114 WARNING("exec plugin: The config option `%s' needs at least two "
119 if ((ci->values[0].type != OCONFIG_TYPE_STRING) ||
120 (ci->values[1].type != OCONFIG_TYPE_STRING)) {
121 WARNING("exec plugin: The first two arguments to the `%s' option must "
122 "be string arguments.",
127 pl = calloc(1, sizeof(*pl));
129 ERROR("exec plugin: calloc failed.");
133 if (strcasecmp("NotificationExec", ci->key) == 0)
134 pl->flags |= PL_NOTIF_ACTION;
136 pl->flags |= PL_NORMAL;
138 pl->user = strdup(ci->values[0].value.string);
139 if (pl->user == NULL) {
140 ERROR("exec plugin: strdup failed.");
145 pl->group = strchr(pl->user, ':');
146 if (pl->group != NULL) {
151 pl->exec = strdup(ci->values[1].value.string);
152 if (pl->exec == NULL) {
153 ERROR("exec plugin: strdup failed.");
159 pl->argv = calloc(ci->values_num, sizeof(*pl->argv));
160 if (pl->argv == NULL) {
161 ERROR("exec plugin: calloc failed.");
169 char *tmp = strrchr(ci->values[1].value.string, '/');
171 sstrncpy(buffer, ci->values[1].value.string, sizeof(buffer));
173 sstrncpy(buffer, tmp + 1, sizeof(buffer));
175 pl->argv[0] = strdup(buffer);
176 if (pl->argv[0] == NULL) {
177 ERROR("exec plugin: strdup failed.");
185 for (i = 1; i < (ci->values_num - 1); i++) {
186 if (ci->values[i + 1].type == OCONFIG_TYPE_STRING) {
187 pl->argv[i] = strdup(ci->values[i + 1].value.string);
189 if (ci->values[i + 1].type == OCONFIG_TYPE_NUMBER) {
190 ssnprintf(buffer, sizeof(buffer), "%lf",
191 ci->values[i + 1].value.number);
193 if (ci->values[i + 1].value.boolean)
194 sstrncpy(buffer, "true", sizeof(buffer));
196 sstrncpy(buffer, "false", sizeof(buffer));
199 pl->argv[i] = strdup(buffer);
202 if (pl->argv[i] == NULL) {
203 ERROR("exec plugin: strdup failed.");
208 if (i < (ci->values_num - 1)) {
219 for (i = 0; pl->argv[i] != NULL; i++) {
220 DEBUG("exec plugin: argv[%i] = %s", i, pl->argv[i]);
227 } /* int exec_config_exec }}} */
229 static int exec_config(oconfig_item_t *ci) /* {{{ */
231 for (int i = 0; i < ci->children_num; i++) {
232 oconfig_item_t *child = ci->children + i;
233 if ((strcasecmp("Exec", child->key) == 0) ||
234 (strcasecmp("NotificationExec", child->key) == 0))
235 exec_config_exec(child);
237 WARNING("exec plugin: Unknown config option `%s'.", child->key);
242 } /* int exec_config }}} */
244 static void set_environment(void) /* {{{ */
249 ssnprintf(buffer, sizeof(buffer), "%.3f",
250 CDTIME_T_TO_DOUBLE(plugin_get_interval()));
251 setenv("COLLECTD_INTERVAL", buffer, /* overwrite = */ 1);
253 sstrncpy(buffer, hostname_g, sizeof(buffer));
254 setenv("COLLECTD_HOSTNAME", buffer, /* overwrite = */ 1);
256 ssnprintf(buffer, sizeof(buffer), "COLLECTD_INTERVAL=%.3f",
257 CDTIME_T_TO_DOUBLE(plugin_get_interval()));
260 ssnprintf(buffer, sizeof(buffer), "COLLECTD_HOSTNAME=%s", hostname_g);
263 } /* }}} void set_environment */
265 __attribute__((noreturn)) static void exec_child(program_list_t *pl, int uid,
266 int gid, int egid) /* {{{ */
279 if ((gid != egid) && (egid != -1)) {
284 setgroups(glist_len, glist);
286 #endif /* HAVE_SETGROUPS */
288 status = setgid(gid);
290 ERROR("exec plugin: setgid (%i) failed: %s", gid,
291 sstrerror(errno, errbuf, sizeof(errbuf)));
296 status = setegid(egid);
298 ERROR("exec plugin: setegid (%i) failed: %s", egid,
299 sstrerror(errno, errbuf, sizeof(errbuf)));
304 status = setuid(uid);
306 ERROR("exec plugin: setuid (%i) failed: %s", uid,
307 sstrerror(errno, errbuf, sizeof(errbuf)));
311 execvp(pl->exec, pl->argv);
313 ERROR("exec plugin: Failed to execute ``%s'': %s", pl->exec,
314 sstrerror(errno, errbuf, sizeof(errbuf)));
316 } /* void exec_child }}} */
318 static void reset_signal_mask(void) /* {{{ */
323 sigprocmask(SIG_SETMASK, &ss, /* old mask = */ NULL);
324 } /* }}} void reset_signal_mask */
326 static int create_pipe(int fd_pipe[2]) /* {{{ */
331 status = pipe(fd_pipe);
333 ERROR("exec plugin: pipe failed: %s",
334 sstrerror(errno, errbuf, sizeof(errbuf)));
339 } /* }}} int create_pipe */
341 static void close_pipe(int fd_pipe[2]) /* {{{ */
343 if (fd_pipe[0] != -1)
346 if (fd_pipe[1] != -1)
348 } /* }}} void close_pipe */
351 * Creates three pipes (one for reading, one for writing and one for errors),
352 * forks a child, sets up the pipes so that fd_in is connected to STDIN of
353 * the child and fd_out is connected to STDOUT and fd_err is connected to STDERR
354 * of the child. Then is calls `exec_child'.
356 static int fork_child(program_list_t *pl, int *fd_in, int *fd_out,
357 int *fd_err) /* {{{ */
359 int fd_pipe_in[2] = {-1, -1};
360 int fd_pipe_out[2] = {-1, -1};
361 int fd_pipe_err[2] = {-1, -1};
370 struct passwd *sp_ptr;
377 if ((create_pipe(fd_pipe_in) == -1) || (create_pipe(fd_pipe_out) == -1) ||
378 (create_pipe(fd_pipe_err) == -1))
382 status = getpwnam_r(pl->user, &sp, nambuf, sizeof(nambuf), &sp_ptr);
384 ERROR("exec plugin: Failed to get user information for user ``%s'': %s",
385 pl->user, sstrerror(errno, errbuf, sizeof(errbuf)));
389 if (sp_ptr == NULL) {
390 ERROR("exec plugin: No such user: `%s'", pl->user);
397 ERROR("exec plugin: Cowardly refusing to exec program as root.");
401 /* The group configured in the configfile is set as effective group, because
402 * this way the forked process can (re-)gain the user's primary group. */
404 if (NULL != pl->group) {
405 if ('\0' != *pl->group) {
406 struct group *gr_ptr = NULL;
409 status = getgrnam_r(pl->group, &gr, nambuf, sizeof(nambuf), &gr_ptr);
411 ERROR("exec plugin: Failed to get group information "
412 "for group ``%s'': %s",
413 pl->group, sstrerror(errno, errbuf, sizeof(errbuf)));
416 if (NULL == gr_ptr) {
417 ERROR("exec plugin: No such group: `%s'", pl->group);
425 } /* if (pl->group == NULL) */
429 ERROR("exec plugin: fork failed: %s",
430 sstrerror(errno, errbuf, sizeof(errbuf)));
432 } else if (pid == 0) {
435 /* Close all file descriptors but the pipe end we need. */
436 fd_num = getdtablesize();
437 for (int fd = 0; fd < fd_num; fd++) {
438 if ((fd == fd_pipe_in[0]) || (fd == fd_pipe_out[1]) ||
439 (fd == fd_pipe_err[1]))
444 /* Connect the `in' pipe to STDIN */
445 if (fd_pipe_in[0] != STDIN_FILENO) {
446 dup2(fd_pipe_in[0], STDIN_FILENO);
447 close(fd_pipe_in[0]);
450 /* Now connect the `out' pipe to STDOUT */
451 if (fd_pipe_out[1] != STDOUT_FILENO) {
452 dup2(fd_pipe_out[1], STDOUT_FILENO);
453 close(fd_pipe_out[1]);
456 /* Now connect the `err' pipe to STDERR */
457 if (fd_pipe_err[1] != STDERR_FILENO) {
458 dup2(fd_pipe_err[1], STDERR_FILENO);
459 close(fd_pipe_err[1]);
464 /* Unblock all signals */
467 exec_child(pl, uid, gid, egid);
468 /* does not return */
471 close(fd_pipe_in[0]);
472 close(fd_pipe_out[1]);
473 close(fd_pipe_err[1]);
476 *fd_in = fd_pipe_in[1];
478 close(fd_pipe_in[1]);
481 *fd_out = fd_pipe_out[0];
483 close(fd_pipe_out[0]);
486 *fd_err = fd_pipe_err[0];
488 close(fd_pipe_err[0]);
493 close_pipe(fd_pipe_in);
494 close_pipe(fd_pipe_out);
495 close_pipe(fd_pipe_err);
498 } /* int fork_child }}} */
500 static int parse_line(char *buffer) /* {{{ */
502 if (strncasecmp("PUTVAL", buffer, strlen("PUTVAL")) == 0)
503 return (cmd_handle_putval(stdout, buffer));
504 else if (strncasecmp("PUTNOTIF", buffer, strlen("PUTNOTIF")) == 0)
505 return (handle_putnotif(stdout, buffer));
507 ERROR("exec plugin: Unable to parse command, ignoring line: \"%s\"",
511 } /* int parse_line }}} */
513 static void *exec_read_one(void *arg) /* {{{ */
515 program_list_t *pl = (program_list_t *)arg;
516 int fd, fd_err, highest_fd;
519 char buffer[1200]; /* if not completely read */
520 char buffer_err[1024];
521 char *pbuffer = buffer;
522 char *pbuffer_err = buffer_err;
524 status = fork_child(pl, NULL, &fd, &fd_err);
526 /* Reset the "running" flag */
527 pthread_mutex_lock(&pl_lock);
528 pl->flags &= ~PL_RUNNING;
529 pthread_mutex_unlock(&pl_lock);
530 pthread_exit((void *)1);
534 assert(pl->pid != 0);
538 FD_SET(fd_err, &fdset);
540 /* Determine the highest file descriptor */
541 highest_fd = (fd > fd_err) ? fd : fd_err;
543 /* We use a copy of fdset, as select modifies it */
549 status = select(highest_fd + 1, ©, NULL, NULL, NULL);
556 if (FD_ISSET(fd, ©)) {
559 len = read(fd, pbuffer, sizeof(buffer) - 1 - (pbuffer - buffer));
562 if (errno == EAGAIN || errno == EINTR)
566 break; /* We've reached EOF */
570 len += pbuffer - buffer;
573 while ((pnl = strchr(pbuffer, '\n'))) {
575 if (*(pnl - 1) == '\r')
582 /* not completely read ? */
583 if (pbuffer - buffer < len) {
584 len -= pbuffer - buffer;
585 memmove(buffer, pbuffer, len);
586 pbuffer = buffer + len;
589 } else if (FD_ISSET(fd_err, ©)) {
592 len = read(fd_err, pbuffer_err,
593 sizeof(buffer_err) - 1 - (pbuffer_err - buffer_err));
596 if (errno == EAGAIN || errno == EINTR)
599 } else if (len == 0) {
600 /* We've reached EOF */
601 NOTICE("exec plugin: Program `%s' has closed STDERR.", pl->exec);
603 /* Remove file descriptor form select() set. */
604 FD_CLR(fd_err, &fdset);
608 /* Clean up file descriptor */
614 pbuffer_err[len] = '\0';
616 len += pbuffer_err - buffer_err;
617 pbuffer_err = buffer_err;
619 while ((pnl = strchr(pbuffer_err, '\n'))) {
621 if (*(pnl - 1) == '\r')
624 ERROR("exec plugin: exec_read_one: error = %s", pbuffer_err);
628 /* not completely read ? */
629 if (pbuffer_err - buffer_err < len) {
630 len -= pbuffer_err - buffer_err;
631 memmove(buffer_err, pbuffer_err, len);
632 pbuffer_err = buffer_err + len;
634 pbuffer_err = buffer_err;
640 DEBUG("exec plugin: exec_read_one: Waiting for `%s' to exit.", pl->exec);
641 if (waitpid(pl->pid, &status, 0) > 0)
644 DEBUG("exec plugin: Child %i exited with status %i.", (int)pl->pid,
649 pthread_mutex_lock(&pl_lock);
650 pl->flags &= ~PL_RUNNING;
651 pthread_mutex_unlock(&pl_lock);
657 pthread_exit((void *)0);
659 } /* void *exec_read_one }}} */
661 static void *exec_notification_one(void *arg) /* {{{ */
663 program_list_t *pl = ((program_list_and_notification_t *)arg)->pl;
664 notification_t *n = &((program_list_and_notification_t *)arg)->n;
669 const char *severity;
671 pid = fork_child(pl, &fd, NULL, NULL);
674 pthread_exit((void *)1);
677 fh = fdopen(fd, "w");
680 ERROR("exec plugin: fdopen (%i) failed: %s", fd,
681 sstrerror(errno, errbuf, sizeof(errbuf)));
685 pthread_exit((void *)1);
688 severity = "FAILURE";
689 if (n->severity == NOTIF_WARNING)
690 severity = "WARNING";
691 else if (n->severity == NOTIF_OKAY)
694 fprintf(fh, "Severity: %s\n"
696 severity, CDTIME_T_TO_DOUBLE(n->time));
698 /* Print the optional fields */
699 if (strlen(n->host) > 0)
700 fprintf(fh, "Host: %s\n", n->host);
701 if (strlen(n->plugin) > 0)
702 fprintf(fh, "Plugin: %s\n", n->plugin);
703 if (strlen(n->plugin_instance) > 0)
704 fprintf(fh, "PluginInstance: %s\n", n->plugin_instance);
705 if (strlen(n->type) > 0)
706 fprintf(fh, "Type: %s\n", n->type);
707 if (strlen(n->type_instance) > 0)
708 fprintf(fh, "TypeInstance: %s\n", n->type_instance);
710 for (notification_meta_t *meta = n->meta; meta != NULL; meta = meta->next) {
711 if (meta->type == NM_TYPE_STRING)
712 fprintf(fh, "%s: %s\n", meta->name, meta->nm_value.nm_string);
713 else if (meta->type == NM_TYPE_SIGNED_INT)
714 fprintf(fh, "%s: %" PRIi64 "\n", meta->name,
715 meta->nm_value.nm_signed_int);
716 else if (meta->type == NM_TYPE_UNSIGNED_INT)
717 fprintf(fh, "%s: %" PRIu64 "\n", meta->name,
718 meta->nm_value.nm_unsigned_int);
719 else if (meta->type == NM_TYPE_DOUBLE)
720 fprintf(fh, "%s: %e\n", meta->name, meta->nm_value.nm_double);
721 else if (meta->type == NM_TYPE_BOOLEAN)
722 fprintf(fh, "%s: %s\n", meta->name,
723 meta->nm_value.nm_boolean ? "true" : "false");
726 fprintf(fh, "\n%s\n", n->message);
731 waitpid(pid, &status, 0);
733 DEBUG("exec plugin: Child %i exited with status %i.", pid, status);
736 plugin_notification_meta_free(n->meta);
739 pthread_exit((void *)0);
741 } /* void *exec_notification_one }}} */
743 static int exec_init(void) /* {{{ */
745 struct sigaction sa = {.sa_handler = sigchld_handler};
747 sigaction(SIGCHLD, &sa, NULL);
749 #if defined(HAVE_SYS_CAPABILITY_H) && defined(CAP_SETUID) && defined(CAP_SETGID)
750 if ((check_capability(CAP_SETUID) != 0) ||
751 (check_capability(CAP_SETGID) != 0)) {
754 "exec plugin: Running collectd as root, but the CAP_SETUID "
755 "or CAP_SETGID capabilities are missing. The plugin's read function "
756 "will probably fail. Is your init system dropping capabilities?");
759 "exec plugin: collectd doesn't have the CAP_SETUID or "
760 "CAP_SETGID capabilities. If you don't want to run collectd as root, "
761 "try running \"setcap 'cap_setuid=ep cap_setgid=ep'\" on the "
767 } /* int exec_init }}} */
769 static int exec_read(void) /* {{{ */
771 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next) {
775 /* Only execute `normal' style executables here. */
776 if ((pl->flags & PL_NORMAL) == 0)
779 pthread_mutex_lock(&pl_lock);
780 /* Skip if a child is already running. */
781 if ((pl->flags & PL_RUNNING) != 0) {
782 pthread_mutex_unlock(&pl_lock);
785 pl->flags |= PL_RUNNING;
786 pthread_mutex_unlock(&pl_lock);
788 pthread_attr_init(&attr);
789 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
790 plugin_thread_create(&t, &attr, exec_read_one, (void *)pl, "exec read");
791 pthread_attr_destroy(&attr);
795 } /* int exec_read }}} */
797 static int exec_notification(const notification_t *n, /* {{{ */
798 user_data_t __attribute__((unused)) * user_data) {
799 program_list_and_notification_t *pln;
801 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next) {
805 /* Only execute `notification' style executables here. */
806 if ((pl->flags & PL_NOTIF_ACTION) == 0)
809 /* Skip if a child is already running. */
813 pln = malloc(sizeof(*pln));
815 ERROR("exec plugin: malloc failed.");
820 memcpy(&pln->n, n, sizeof(notification_t));
822 /* Set the `meta' member to NULL, otherwise `plugin_notification_meta_copy'
823 * will run into an endless loop. */
825 plugin_notification_meta_copy(&pln->n, n);
827 pthread_attr_init(&attr);
828 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
829 plugin_thread_create(&t, &attr, exec_notification_one, (void *)pln,
831 pthread_attr_destroy(&attr);
835 } /* }}} int exec_notification */
837 static int exec_shutdown(void) /* {{{ */
840 program_list_t *next;
847 kill(pl->pid, SIGTERM);
848 INFO("exec plugin: Sent SIGTERM to %hu", (unsigned short int)pl->pid);
859 } /* int exec_shutdown }}} */
861 void module_register(void) {
862 plugin_register_complex_config("exec", exec_config);
863 plugin_register_init("exec", exec_init);
864 plugin_register_read("exec", exec_read);
865 plugin_register_notification("exec", exec_notification,
866 /* user_data = */ NULL);
867 plugin_register_shutdown("exec", exec_shutdown);
868 } /* void module_register */