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 const long int MAX_GRBUF_SIZE = 65536;
88 static program_list_t *pl_head = NULL;
89 static pthread_mutex_t pl_lock = PTHREAD_MUTEX_INITIALIZER;
94 static void sigchld_handler(int __attribute__((unused)) signal) /* {{{ */
98 while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
100 for (pl = pl_head; pl != NULL; pl = pl->next)
105 } /* while (waitpid) */
106 } /* void sigchld_handler }}} */
108 static int exec_config_exec(oconfig_item_t *ci) /* {{{ */
114 if (ci->children_num != 0) {
115 WARNING("exec plugin: The config option `%s' may not be a block.", ci->key);
118 if (ci->values_num < 2) {
119 WARNING("exec plugin: The config option `%s' needs at least two "
124 if ((ci->values[0].type != OCONFIG_TYPE_STRING) ||
125 (ci->values[1].type != OCONFIG_TYPE_STRING)) {
126 WARNING("exec plugin: The first two arguments to the `%s' option must "
127 "be string arguments.",
132 pl = calloc(1, sizeof(*pl));
134 ERROR("exec plugin: calloc failed.");
138 if (strcasecmp("NotificationExec", ci->key) == 0)
139 pl->flags |= PL_NOTIF_ACTION;
141 pl->flags |= PL_NORMAL;
143 pl->user = strdup(ci->values[0].value.string);
144 if (pl->user == NULL) {
145 ERROR("exec plugin: strdup failed.");
150 pl->group = strchr(pl->user, ':');
151 if (pl->group != NULL) {
156 pl->exec = strdup(ci->values[1].value.string);
157 if (pl->exec == NULL) {
158 ERROR("exec plugin: strdup failed.");
164 pl->argv = calloc(ci->values_num, sizeof(*pl->argv));
165 if (pl->argv == NULL) {
166 ERROR("exec plugin: calloc failed.");
174 char *tmp = strrchr(ci->values[1].value.string, '/');
176 sstrncpy(buffer, ci->values[1].value.string, sizeof(buffer));
178 sstrncpy(buffer, tmp + 1, sizeof(buffer));
180 pl->argv[0] = strdup(buffer);
181 if (pl->argv[0] == NULL) {
182 ERROR("exec plugin: strdup failed.");
190 for (i = 1; i < (ci->values_num - 1); i++) {
191 if (ci->values[i + 1].type == OCONFIG_TYPE_STRING) {
192 pl->argv[i] = strdup(ci->values[i + 1].value.string);
194 if (ci->values[i + 1].type == OCONFIG_TYPE_NUMBER) {
195 snprintf(buffer, sizeof(buffer), "%lf", ci->values[i + 1].value.number);
197 if (ci->values[i + 1].value.boolean)
198 sstrncpy(buffer, "true", sizeof(buffer));
200 sstrncpy(buffer, "false", sizeof(buffer));
203 pl->argv[i] = strdup(buffer);
206 if (pl->argv[i] == NULL) {
207 ERROR("exec plugin: strdup failed.");
212 if (i < (ci->values_num - 1)) {
223 for (i = 0; pl->argv[i] != NULL; i++) {
224 DEBUG("exec plugin: argv[%i] = %s", i, pl->argv[i]);
231 } /* int exec_config_exec }}} */
233 static int exec_config(oconfig_item_t *ci) /* {{{ */
235 for (int i = 0; i < ci->children_num; i++) {
236 oconfig_item_t *child = ci->children + i;
237 if ((strcasecmp("Exec", child->key) == 0) ||
238 (strcasecmp("NotificationExec", child->key) == 0))
239 exec_config_exec(child);
241 WARNING("exec plugin: Unknown config option `%s'.", child->key);
246 } /* int exec_config }}} */
248 #if !defined(HAVE_SETENV)
249 static char env_interval[64];
250 // max hostname len is 255, so this should be enough
251 static char env_hostname[300];
254 static void set_environment(void) /* {{{ */
259 snprintf(buffer, sizeof(buffer), "%.3f",
260 CDTIME_T_TO_DOUBLE(plugin_get_interval()));
261 setenv("COLLECTD_INTERVAL", buffer, /* overwrite = */ 1);
263 sstrncpy(buffer, hostname_g, sizeof(buffer));
264 setenv("COLLECTD_HOSTNAME", buffer, /* overwrite = */ 1);
266 snprintf(env_interval, sizeof(env_interval), "COLLECTD_INTERVAL=%.3f",
267 CDTIME_T_TO_DOUBLE(plugin_get_interval()));
268 putenv(env_interval);
270 snprintf(env_hostname, sizeof(env_hostname), "COLLECTD_HOSTNAME=%s",
272 putenv(env_hostname);
274 } /* }}} void set_environment */
276 __attribute__((noreturn)) static void exec_child(program_list_t *pl, int uid,
277 int gid, int egid) /* {{{ */
290 if ((gid != egid) && (egid != -1)) {
295 setgroups(glist_len, glist);
297 #endif /* HAVE_SETGROUPS */
299 status = setgid(gid);
301 ERROR("exec plugin: setgid (%i) failed: %s", gid,
302 sstrerror(errno, errbuf, sizeof(errbuf)));
307 status = setegid(egid);
309 ERROR("exec plugin: setegid (%i) failed: %s", egid,
310 sstrerror(errno, errbuf, sizeof(errbuf)));
315 status = setuid(uid);
317 ERROR("exec plugin: setuid (%i) failed: %s", uid,
318 sstrerror(errno, errbuf, sizeof(errbuf)));
322 execvp(pl->exec, pl->argv);
324 ERROR("exec plugin: Failed to execute ``%s'': %s", pl->exec,
325 sstrerror(errno, errbuf, sizeof(errbuf)));
327 } /* void exec_child }}} */
329 static void reset_signal_mask(void) /* {{{ */
334 sigprocmask(SIG_SETMASK, &ss, /* old mask = */ NULL);
335 } /* }}} void reset_signal_mask */
337 static int create_pipe(int fd_pipe[2]) /* {{{ */
342 status = pipe(fd_pipe);
344 ERROR("exec plugin: pipe failed: %s",
345 sstrerror(errno, errbuf, sizeof(errbuf)));
350 } /* }}} int create_pipe */
352 static void close_pipe(int fd_pipe[2]) /* {{{ */
354 if (fd_pipe[0] != -1)
357 if (fd_pipe[1] != -1)
359 } /* }}} void close_pipe */
362 * Get effective group ID from group name.
364 * pl :program list struct with group name
365 * gid :group id to fallback in case egid cannot be determined.
367 * egid effective group id if successfull,
368 * -1 if group is not defined/not found.
369 * -2 for any buffer allocation error.
371 static int getegr_id(program_list_t *pl, int gid) /* {{{ */
373 if (pl->group == NULL) {
376 if (strcmp(pl->group, "") == 0) {
379 struct group *gr_ptr = NULL;
382 long int grbuf_size = sysconf(_SC_GETGR_R_SIZE_MAX);
384 grbuf_size = sysconf(_SC_PAGESIZE);
392 temp = realloc(grbuf, grbuf_size);
394 ERROR("exec plugin: getegr_id for %s: realloc buffer[%ld] failed ",
395 pl->group, grbuf_size);
400 if (getgrnam_r(pl->group, &gr, grbuf, grbuf_size, &gr_ptr) == 0) {
402 if (gr_ptr == NULL) {
403 ERROR("exec plugin: No such group: `%s'", pl->group);
407 } else if (errno == ERANGE) {
408 grbuf_size += grbuf_size; // increment buffer size and try again
411 ERROR("exec plugin: getegr_id failed %s",
412 sstrerror(errno, errbuf, sizeof(errbuf)));
416 } while (grbuf_size <= MAX_GRBUF_SIZE);
417 ERROR("exec plugin: getegr_id Max grbuf size reached for %s", pl->group);
423 * Creates three pipes (one for reading, one for writing and one for errors),
424 * forks a child, sets up the pipes so that fd_in is connected to STDIN of
425 * the child and fd_out is connected to STDOUT and fd_err is connected to STDERR
426 * of the child. Then is calls `exec_child'.
428 static int fork_child(program_list_t *pl, int *fd_in, int *fd_out,
429 int *fd_err) /* {{{ */
431 int fd_pipe_in[2] = {-1, -1};
432 int fd_pipe_out[2] = {-1, -1};
433 int fd_pipe_err[2] = {-1, -1};
442 struct passwd *sp_ptr;
448 long int nambuf_size = sysconf(_SC_GETPW_R_SIZE_MAX);
449 if (nambuf_size <= 0)
450 nambuf_size = sysconf(_SC_PAGESIZE);
451 if (nambuf_size <= 0)
453 char nambuf[nambuf_size];
455 if ((create_pipe(fd_pipe_in) == -1) || (create_pipe(fd_pipe_out) == -1) ||
456 (create_pipe(fd_pipe_err) == -1))
460 status = getpwnam_r(pl->user, &sp, nambuf, sizeof(nambuf), &sp_ptr);
462 ERROR("exec plugin: Failed to get user information for user ``%s'': %s",
463 pl->user, sstrerror(status, errbuf, sizeof(errbuf)));
467 if (sp_ptr == NULL) {
468 ERROR("exec plugin: No such user: `%s'", pl->user);
475 ERROR("exec plugin: Cowardly refusing to exec program as root.");
479 egid = getegr_id(pl, gid);
486 ERROR("exec plugin: fork failed: %s",
487 sstrerror(errno, errbuf, sizeof(errbuf)));
489 } else if (pid == 0) {
492 /* Close all file descriptors but the pipe end we need. */
493 fd_num = getdtablesize();
494 for (int fd = 0; fd < fd_num; fd++) {
495 if ((fd == fd_pipe_in[0]) || (fd == fd_pipe_out[1]) ||
496 (fd == fd_pipe_err[1]))
501 /* Connect the `in' pipe to STDIN */
502 if (fd_pipe_in[0] != STDIN_FILENO) {
503 dup2(fd_pipe_in[0], STDIN_FILENO);
504 close(fd_pipe_in[0]);
507 /* Now connect the `out' pipe to STDOUT */
508 if (fd_pipe_out[1] != STDOUT_FILENO) {
509 dup2(fd_pipe_out[1], STDOUT_FILENO);
510 close(fd_pipe_out[1]);
513 /* Now connect the `err' pipe to STDERR */
514 if (fd_pipe_err[1] != STDERR_FILENO) {
515 dup2(fd_pipe_err[1], STDERR_FILENO);
516 close(fd_pipe_err[1]);
521 /* Unblock all signals */
524 exec_child(pl, uid, gid, egid);
525 /* does not return */
528 close(fd_pipe_in[0]);
529 close(fd_pipe_out[1]);
530 close(fd_pipe_err[1]);
533 *fd_in = fd_pipe_in[1];
535 close(fd_pipe_in[1]);
538 *fd_out = fd_pipe_out[0];
540 close(fd_pipe_out[0]);
543 *fd_err = fd_pipe_err[0];
545 close(fd_pipe_err[0]);
550 close_pipe(fd_pipe_in);
551 close_pipe(fd_pipe_out);
552 close_pipe(fd_pipe_err);
555 } /* int fork_child }}} */
557 static int parse_line(char *buffer) /* {{{ */
559 if (strncasecmp("PUTVAL", buffer, strlen("PUTVAL")) == 0)
560 return cmd_handle_putval(stdout, buffer);
561 else if (strncasecmp("PUTNOTIF", buffer, strlen("PUTNOTIF")) == 0)
562 return handle_putnotif(stdout, buffer);
564 ERROR("exec plugin: Unable to parse command, ignoring line: \"%s\"",
568 } /* int parse_line }}} */
570 static void *exec_read_one(void *arg) /* {{{ */
572 program_list_t *pl = (program_list_t *)arg;
573 int fd, fd_err, highest_fd;
576 char buffer[1200]; /* if not completely read */
577 char buffer_err[1024];
578 char *pbuffer = buffer;
579 char *pbuffer_err = buffer_err;
581 status = fork_child(pl, NULL, &fd, &fd_err);
583 /* Reset the "running" flag */
584 pthread_mutex_lock(&pl_lock);
585 pl->flags &= ~PL_RUNNING;
586 pthread_mutex_unlock(&pl_lock);
587 pthread_exit((void *)1);
591 assert(pl->pid != 0);
595 FD_SET(fd_err, &fdset);
597 /* Determine the highest file descriptor */
598 highest_fd = (fd > fd_err) ? fd : fd_err;
600 /* We use a copy of fdset, as select modifies it */
606 status = select(highest_fd + 1, ©, NULL, NULL, NULL);
613 if (FD_ISSET(fd, ©)) {
616 len = read(fd, pbuffer, sizeof(buffer) - 1 - (pbuffer - buffer));
619 if (errno == EAGAIN || errno == EINTR)
623 break; /* We've reached EOF */
627 len += pbuffer - buffer;
630 while ((pnl = strchr(pbuffer, '\n'))) {
632 if (*(pnl - 1) == '\r')
639 /* not completely read ? */
640 if (pbuffer - buffer < len) {
641 len -= pbuffer - buffer;
642 memmove(buffer, pbuffer, len);
643 pbuffer = buffer + len;
646 } else if (FD_ISSET(fd_err, ©)) {
649 len = read(fd_err, pbuffer_err,
650 sizeof(buffer_err) - 1 - (pbuffer_err - buffer_err));
653 if (errno == EAGAIN || errno == EINTR)
656 } else if (len == 0) {
657 /* We've reached EOF */
658 NOTICE("exec plugin: Program `%s' has closed STDERR.", pl->exec);
660 /* Remove file descriptor form select() set. */
661 FD_CLR(fd_err, &fdset);
665 /* Clean up file descriptor */
671 pbuffer_err[len] = '\0';
673 len += pbuffer_err - buffer_err;
674 pbuffer_err = buffer_err;
676 while ((pnl = strchr(pbuffer_err, '\n'))) {
678 if (*(pnl - 1) == '\r')
681 ERROR("exec plugin: exec_read_one: error = %s", pbuffer_err);
685 /* not completely read ? */
686 if (pbuffer_err - buffer_err < len) {
687 len -= pbuffer_err - buffer_err;
688 memmove(buffer_err, pbuffer_err, len);
689 pbuffer_err = buffer_err + len;
691 pbuffer_err = buffer_err;
697 DEBUG("exec plugin: exec_read_one: Waiting for `%s' to exit.", pl->exec);
698 if (waitpid(pl->pid, &status, 0) > 0)
701 DEBUG("exec plugin: Child %i exited with status %i.", (int)pl->pid,
706 pthread_mutex_lock(&pl_lock);
707 pl->flags &= ~PL_RUNNING;
708 pthread_mutex_unlock(&pl_lock);
714 pthread_exit((void *)0);
716 } /* void *exec_read_one }}} */
718 static void *exec_notification_one(void *arg) /* {{{ */
720 program_list_t *pl = ((program_list_and_notification_t *)arg)->pl;
721 notification_t *n = &((program_list_and_notification_t *)arg)->n;
726 const char *severity;
728 pid = fork_child(pl, &fd, NULL, NULL);
731 pthread_exit((void *)1);
734 fh = fdopen(fd, "w");
737 ERROR("exec plugin: fdopen (%i) failed: %s", fd,
738 sstrerror(errno, errbuf, sizeof(errbuf)));
742 pthread_exit((void *)1);
745 severity = "FAILURE";
746 if (n->severity == NOTIF_WARNING)
747 severity = "WARNING";
748 else if (n->severity == NOTIF_OKAY)
751 fprintf(fh, "Severity: %s\n"
753 severity, CDTIME_T_TO_DOUBLE(n->time));
755 /* Print the optional fields */
756 if (strlen(n->host) > 0)
757 fprintf(fh, "Host: %s\n", n->host);
758 if (strlen(n->plugin) > 0)
759 fprintf(fh, "Plugin: %s\n", n->plugin);
760 if (strlen(n->plugin_instance) > 0)
761 fprintf(fh, "PluginInstance: %s\n", n->plugin_instance);
762 if (strlen(n->type) > 0)
763 fprintf(fh, "Type: %s\n", n->type);
764 if (strlen(n->type_instance) > 0)
765 fprintf(fh, "TypeInstance: %s\n", n->type_instance);
767 for (notification_meta_t *meta = n->meta; meta != NULL; meta = meta->next) {
768 if (meta->type == NM_TYPE_STRING)
769 fprintf(fh, "%s: %s\n", meta->name, meta->nm_value.nm_string);
770 else if (meta->type == NM_TYPE_SIGNED_INT)
771 fprintf(fh, "%s: %" PRIi64 "\n", meta->name,
772 meta->nm_value.nm_signed_int);
773 else if (meta->type == NM_TYPE_UNSIGNED_INT)
774 fprintf(fh, "%s: %" PRIu64 "\n", meta->name,
775 meta->nm_value.nm_unsigned_int);
776 else if (meta->type == NM_TYPE_DOUBLE)
777 fprintf(fh, "%s: %e\n", meta->name, meta->nm_value.nm_double);
778 else if (meta->type == NM_TYPE_BOOLEAN)
779 fprintf(fh, "%s: %s\n", meta->name,
780 meta->nm_value.nm_boolean ? "true" : "false");
783 fprintf(fh, "\n%s\n", n->message);
788 waitpid(pid, &status, 0);
790 DEBUG("exec plugin: Child %i exited with status %i.", pid, status);
793 plugin_notification_meta_free(n->meta);
796 pthread_exit((void *)0);
798 } /* void *exec_notification_one }}} */
800 static int exec_init(void) /* {{{ */
802 struct sigaction sa = {.sa_handler = sigchld_handler};
804 sigaction(SIGCHLD, &sa, NULL);
806 #if defined(HAVE_SYS_CAPABILITY_H) && defined(CAP_SETUID) && defined(CAP_SETGID)
807 if ((check_capability(CAP_SETUID) != 0) ||
808 (check_capability(CAP_SETGID) != 0)) {
811 "exec plugin: Running collectd as root, but the CAP_SETUID "
812 "or CAP_SETGID capabilities are missing. The plugin's read function "
813 "will probably fail. Is your init system dropping capabilities?");
816 "exec plugin: collectd doesn't have the CAP_SETUID or "
817 "CAP_SETGID capabilities. If you don't want to run collectd as root, "
818 "try running \"setcap 'cap_setuid=ep cap_setgid=ep'\" on the "
824 } /* int exec_init }}} */
826 static int exec_read(void) /* {{{ */
828 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next) {
832 /* Only execute `normal' style executables here. */
833 if ((pl->flags & PL_NORMAL) == 0)
836 pthread_mutex_lock(&pl_lock);
837 /* Skip if a child is already running. */
838 if ((pl->flags & PL_RUNNING) != 0) {
839 pthread_mutex_unlock(&pl_lock);
842 pl->flags |= PL_RUNNING;
843 pthread_mutex_unlock(&pl_lock);
845 pthread_attr_init(&attr);
846 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
848 plugin_thread_create(&t, &attr, exec_read_one, (void *)pl, "exec read");
850 ERROR("exec plugin: plugin_thread_create failed.");
852 pthread_attr_destroy(&attr);
856 } /* int exec_read }}} */
858 static int exec_notification(const notification_t *n, /* {{{ */
859 user_data_t __attribute__((unused)) * user_data) {
860 program_list_and_notification_t *pln;
862 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next) {
866 /* Only execute `notification' style executables here. */
867 if ((pl->flags & PL_NOTIF_ACTION) == 0)
870 /* Skip if a child is already running. */
874 pln = malloc(sizeof(*pln));
876 ERROR("exec plugin: malloc failed.");
881 memcpy(&pln->n, n, sizeof(notification_t));
883 /* Set the `meta' member to NULL, otherwise `plugin_notification_meta_copy'
884 * will run into an endless loop. */
886 plugin_notification_meta_copy(&pln->n, n);
888 pthread_attr_init(&attr);
889 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
890 int status = plugin_thread_create(&t, &attr, exec_notification_one,
891 (void *)pln, "exec notify");
893 ERROR("exec plugin: plugin_thread_create failed.");
895 pthread_attr_destroy(&attr);
899 } /* }}} int exec_notification */
901 static int exec_shutdown(void) /* {{{ */
904 program_list_t *next;
911 kill(pl->pid, SIGTERM);
912 INFO("exec plugin: Sent SIGTERM to %hu", (unsigned short int)pl->pid);
923 } /* int exec_shutdown }}} */
925 void module_register(void) {
926 plugin_register_complex_config("exec", exec_config);
927 plugin_register_init("exec", exec_init);
928 plugin_register_read("exec", exec_read);
929 plugin_register_notification("exec", exec_notification,
930 /* user_data = */ NULL);
931 plugin_register_shutdown("exec", exec_shutdown);
932 } /* void module_register */