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 snprintf(buffer, sizeof(buffer), "%lf", ci->values[i + 1].value.number);
192 if (ci->values[i + 1].value.boolean)
193 sstrncpy(buffer, "true", sizeof(buffer));
195 sstrncpy(buffer, "false", sizeof(buffer));
198 pl->argv[i] = strdup(buffer);
201 if (pl->argv[i] == NULL) {
202 ERROR("exec plugin: strdup failed.");
207 if (i < (ci->values_num - 1)) {
218 for (i = 0; pl->argv[i] != NULL; i++) {
219 DEBUG("exec plugin: argv[%i] = %s", i, pl->argv[i]);
226 } /* int exec_config_exec }}} */
228 static int exec_config(oconfig_item_t *ci) /* {{{ */
230 for (int i = 0; i < ci->children_num; i++) {
231 oconfig_item_t *child = ci->children + i;
232 if ((strcasecmp("Exec", child->key) == 0) ||
233 (strcasecmp("NotificationExec", child->key) == 0))
234 exec_config_exec(child);
236 WARNING("exec plugin: Unknown config option `%s'.", child->key);
241 } /* int exec_config }}} */
243 static void set_environment(void) /* {{{ */
248 snprintf(buffer, sizeof(buffer), "%.3f",
249 CDTIME_T_TO_DOUBLE(plugin_get_interval()));
250 setenv("COLLECTD_INTERVAL", buffer, /* overwrite = */ 1);
252 sstrncpy(buffer, hostname_g, sizeof(buffer));
253 setenv("COLLECTD_HOSTNAME", buffer, /* overwrite = */ 1);
255 snprintf(buffer, sizeof(buffer), "COLLECTD_INTERVAL=%.3f",
256 CDTIME_T_TO_DOUBLE(plugin_get_interval()));
259 snprintf(buffer, sizeof(buffer), "COLLECTD_HOSTNAME=%s", hostname_g);
262 } /* }}} void set_environment */
264 __attribute__((noreturn)) static void exec_child(program_list_t *pl, int uid,
265 int gid, int egid) /* {{{ */
278 if ((gid != egid) && (egid != -1)) {
283 setgroups(glist_len, glist);
285 #endif /* HAVE_SETGROUPS */
287 status = setgid(gid);
289 ERROR("exec plugin: setgid (%i) failed: %s", gid,
290 sstrerror(errno, errbuf, sizeof(errbuf)));
295 status = setegid(egid);
297 ERROR("exec plugin: setegid (%i) failed: %s", egid,
298 sstrerror(errno, errbuf, sizeof(errbuf)));
303 status = setuid(uid);
305 ERROR("exec plugin: setuid (%i) failed: %s", uid,
306 sstrerror(errno, errbuf, sizeof(errbuf)));
310 execvp(pl->exec, pl->argv);
312 ERROR("exec plugin: Failed to execute ``%s'': %s", pl->exec,
313 sstrerror(errno, errbuf, sizeof(errbuf)));
315 } /* void exec_child }}} */
317 static void reset_signal_mask(void) /* {{{ */
322 sigprocmask(SIG_SETMASK, &ss, /* old mask = */ NULL);
323 } /* }}} void reset_signal_mask */
325 static int create_pipe(int fd_pipe[2]) /* {{{ */
330 status = pipe(fd_pipe);
332 ERROR("exec plugin: pipe failed: %s",
333 sstrerror(errno, errbuf, sizeof(errbuf)));
338 } /* }}} int create_pipe */
340 static void close_pipe(int fd_pipe[2]) /* {{{ */
342 if (fd_pipe[0] != -1)
345 if (fd_pipe[1] != -1)
347 } /* }}} void close_pipe */
350 * Creates three pipes (one for reading, one for writing and one for errors),
351 * forks a child, sets up the pipes so that fd_in is connected to STDIN of
352 * the child and fd_out is connected to STDOUT and fd_err is connected to STDERR
353 * of the child. Then is calls `exec_child'.
355 static int fork_child(program_list_t *pl, int *fd_in, int *fd_out,
356 int *fd_err) /* {{{ */
358 int fd_pipe_in[2] = {-1, -1};
359 int fd_pipe_out[2] = {-1, -1};
360 int fd_pipe_err[2] = {-1, -1};
369 struct passwd *sp_ptr;
375 long int nambuf_size = sysconf(_SC_GETPW_R_SIZE_MAX);
376 if (nambuf_size <= 0)
377 nambuf_size = sysconf(_SC_PAGESIZE);
378 if (nambuf_size <= 0)
380 char nambuf[nambuf_size];
382 if ((create_pipe(fd_pipe_in) == -1) || (create_pipe(fd_pipe_out) == -1) ||
383 (create_pipe(fd_pipe_err) == -1))
387 status = getpwnam_r(pl->user, &sp, nambuf, sizeof(nambuf), &sp_ptr);
389 ERROR("exec plugin: Failed to get user information for user ``%s'': %s",
390 pl->user, sstrerror(status, errbuf, sizeof(errbuf)));
394 if (sp_ptr == NULL) {
395 ERROR("exec plugin: No such user: `%s'", pl->user);
402 ERROR("exec plugin: Cowardly refusing to exec program as root.");
406 /* The group configured in the configfile is set as effective group, because
407 * this way the forked process can (re-)gain the user's primary group. */
409 if (pl->group != NULL) {
410 if (*pl->group != '\0') {
411 struct group *gr_ptr = NULL;
414 long int grbuf_size = sysconf(_SC_GETGR_R_SIZE_MAX);
416 grbuf_size = sysconf(_SC_PAGESIZE);
419 char grbuf[grbuf_size];
421 status = getgrnam_r(pl->group, &gr, grbuf, sizeof(grbuf), &gr_ptr);
423 ERROR("exec plugin: Failed to get group information "
424 "for group ``%s'': %s",
425 pl->group, sstrerror(status, errbuf, sizeof(errbuf)));
428 if (gr_ptr == NULL) {
429 ERROR("exec plugin: No such group: `%s'", pl->group);
437 } /* if (pl->group == NULL) */
441 ERROR("exec plugin: fork failed: %s",
442 sstrerror(errno, errbuf, sizeof(errbuf)));
444 } else if (pid == 0) {
447 /* Close all file descriptors but the pipe end we need. */
448 fd_num = getdtablesize();
449 for (int fd = 0; fd < fd_num; fd++) {
450 if ((fd == fd_pipe_in[0]) || (fd == fd_pipe_out[1]) ||
451 (fd == fd_pipe_err[1]))
456 /* Connect the `in' pipe to STDIN */
457 if (fd_pipe_in[0] != STDIN_FILENO) {
458 dup2(fd_pipe_in[0], STDIN_FILENO);
459 close(fd_pipe_in[0]);
462 /* Now connect the `out' pipe to STDOUT */
463 if (fd_pipe_out[1] != STDOUT_FILENO) {
464 dup2(fd_pipe_out[1], STDOUT_FILENO);
465 close(fd_pipe_out[1]);
468 /* Now connect the `err' pipe to STDERR */
469 if (fd_pipe_err[1] != STDERR_FILENO) {
470 dup2(fd_pipe_err[1], STDERR_FILENO);
471 close(fd_pipe_err[1]);
476 /* Unblock all signals */
479 exec_child(pl, uid, gid, egid);
480 /* does not return */
483 close(fd_pipe_in[0]);
484 close(fd_pipe_out[1]);
485 close(fd_pipe_err[1]);
488 *fd_in = fd_pipe_in[1];
490 close(fd_pipe_in[1]);
493 *fd_out = fd_pipe_out[0];
495 close(fd_pipe_out[0]);
498 *fd_err = fd_pipe_err[0];
500 close(fd_pipe_err[0]);
505 close_pipe(fd_pipe_in);
506 close_pipe(fd_pipe_out);
507 close_pipe(fd_pipe_err);
510 } /* int fork_child }}} */
512 static int parse_line(char *buffer) /* {{{ */
514 if (strncasecmp("PUTVAL", buffer, strlen("PUTVAL")) == 0)
515 return cmd_handle_putval(stdout, buffer);
516 else if (strncasecmp("PUTNOTIF", buffer, strlen("PUTNOTIF")) == 0)
517 return handle_putnotif(stdout, buffer);
519 ERROR("exec plugin: Unable to parse command, ignoring line: \"%s\"",
523 } /* int parse_line }}} */
525 static void *exec_read_one(void *arg) /* {{{ */
527 program_list_t *pl = (program_list_t *)arg;
528 int fd, fd_err, highest_fd;
531 char buffer[1200]; /* if not completely read */
532 char buffer_err[1024];
533 char *pbuffer = buffer;
534 char *pbuffer_err = buffer_err;
536 status = fork_child(pl, NULL, &fd, &fd_err);
538 /* Reset the "running" flag */
539 pthread_mutex_lock(&pl_lock);
540 pl->flags &= ~PL_RUNNING;
541 pthread_mutex_unlock(&pl_lock);
542 pthread_exit((void *)1);
546 assert(pl->pid != 0);
550 FD_SET(fd_err, &fdset);
552 /* Determine the highest file descriptor */
553 highest_fd = (fd > fd_err) ? fd : fd_err;
555 /* We use a copy of fdset, as select modifies it */
561 status = select(highest_fd + 1, ©, NULL, NULL, NULL);
568 if (FD_ISSET(fd, ©)) {
571 len = read(fd, pbuffer, sizeof(buffer) - 1 - (pbuffer - buffer));
574 if (errno == EAGAIN || errno == EINTR)
578 break; /* We've reached EOF */
582 len += pbuffer - buffer;
585 while ((pnl = strchr(pbuffer, '\n'))) {
587 if (*(pnl - 1) == '\r')
594 /* not completely read ? */
595 if (pbuffer - buffer < len) {
596 len -= pbuffer - buffer;
597 memmove(buffer, pbuffer, len);
598 pbuffer = buffer + len;
601 } else if (FD_ISSET(fd_err, ©)) {
604 len = read(fd_err, pbuffer_err,
605 sizeof(buffer_err) - 1 - (pbuffer_err - buffer_err));
608 if (errno == EAGAIN || errno == EINTR)
611 } else if (len == 0) {
612 /* We've reached EOF */
613 NOTICE("exec plugin: Program `%s' has closed STDERR.", pl->exec);
615 /* Remove file descriptor form select() set. */
616 FD_CLR(fd_err, &fdset);
620 /* Clean up file descriptor */
626 pbuffer_err[len] = '\0';
628 len += pbuffer_err - buffer_err;
629 pbuffer_err = buffer_err;
631 while ((pnl = strchr(pbuffer_err, '\n'))) {
633 if (*(pnl - 1) == '\r')
636 ERROR("exec plugin: exec_read_one: error = %s", pbuffer_err);
640 /* not completely read ? */
641 if (pbuffer_err - buffer_err < len) {
642 len -= pbuffer_err - buffer_err;
643 memmove(buffer_err, pbuffer_err, len);
644 pbuffer_err = buffer_err + len;
646 pbuffer_err = buffer_err;
652 DEBUG("exec plugin: exec_read_one: Waiting for `%s' to exit.", pl->exec);
653 if (waitpid(pl->pid, &status, 0) > 0)
656 DEBUG("exec plugin: Child %i exited with status %i.", (int)pl->pid,
661 pthread_mutex_lock(&pl_lock);
662 pl->flags &= ~PL_RUNNING;
663 pthread_mutex_unlock(&pl_lock);
669 pthread_exit((void *)0);
671 } /* void *exec_read_one }}} */
673 static void *exec_notification_one(void *arg) /* {{{ */
675 program_list_t *pl = ((program_list_and_notification_t *)arg)->pl;
676 notification_t *n = &((program_list_and_notification_t *)arg)->n;
681 const char *severity;
683 pid = fork_child(pl, &fd, NULL, NULL);
686 pthread_exit((void *)1);
689 fh = fdopen(fd, "w");
692 ERROR("exec plugin: fdopen (%i) failed: %s", fd,
693 sstrerror(errno, errbuf, sizeof(errbuf)));
697 pthread_exit((void *)1);
700 severity = "FAILURE";
701 if (n->severity == NOTIF_WARNING)
702 severity = "WARNING";
703 else if (n->severity == NOTIF_OKAY)
706 fprintf(fh, "Severity: %s\n"
708 severity, CDTIME_T_TO_DOUBLE(n->time));
710 /* Print the optional fields */
711 if (strlen(n->host) > 0)
712 fprintf(fh, "Host: %s\n", n->host);
713 if (strlen(n->plugin) > 0)
714 fprintf(fh, "Plugin: %s\n", n->plugin);
715 if (strlen(n->plugin_instance) > 0)
716 fprintf(fh, "PluginInstance: %s\n", n->plugin_instance);
717 if (strlen(n->type) > 0)
718 fprintf(fh, "Type: %s\n", n->type);
719 if (strlen(n->type_instance) > 0)
720 fprintf(fh, "TypeInstance: %s\n", n->type_instance);
722 for (notification_meta_t *meta = n->meta; meta != NULL; meta = meta->next) {
723 if (meta->type == NM_TYPE_STRING)
724 fprintf(fh, "%s: %s\n", meta->name, meta->nm_value.nm_string);
725 else if (meta->type == NM_TYPE_SIGNED_INT)
726 fprintf(fh, "%s: %" PRIi64 "\n", meta->name,
727 meta->nm_value.nm_signed_int);
728 else if (meta->type == NM_TYPE_UNSIGNED_INT)
729 fprintf(fh, "%s: %" PRIu64 "\n", meta->name,
730 meta->nm_value.nm_unsigned_int);
731 else if (meta->type == NM_TYPE_DOUBLE)
732 fprintf(fh, "%s: %e\n", meta->name, meta->nm_value.nm_double);
733 else if (meta->type == NM_TYPE_BOOLEAN)
734 fprintf(fh, "%s: %s\n", meta->name,
735 meta->nm_value.nm_boolean ? "true" : "false");
738 fprintf(fh, "\n%s\n", n->message);
743 waitpid(pid, &status, 0);
745 DEBUG("exec plugin: Child %i exited with status %i.", pid, status);
748 plugin_notification_meta_free(n->meta);
751 pthread_exit((void *)0);
753 } /* void *exec_notification_one }}} */
755 static int exec_init(void) /* {{{ */
757 struct sigaction sa = {.sa_handler = sigchld_handler};
759 sigaction(SIGCHLD, &sa, NULL);
761 #if defined(HAVE_SYS_CAPABILITY_H) && defined(CAP_SETUID) && defined(CAP_SETGID)
762 if ((check_capability(CAP_SETUID) != 0) ||
763 (check_capability(CAP_SETGID) != 0)) {
766 "exec plugin: Running collectd as root, but the CAP_SETUID "
767 "or CAP_SETGID capabilities are missing. The plugin's read function "
768 "will probably fail. Is your init system dropping capabilities?");
771 "exec plugin: collectd doesn't have the CAP_SETUID or "
772 "CAP_SETGID capabilities. If you don't want to run collectd as root, "
773 "try running \"setcap 'cap_setuid=ep cap_setgid=ep'\" on the "
779 } /* int exec_init }}} */
781 static int exec_read(void) /* {{{ */
783 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next) {
787 /* Only execute `normal' style executables here. */
788 if ((pl->flags & PL_NORMAL) == 0)
791 pthread_mutex_lock(&pl_lock);
792 /* Skip if a child is already running. */
793 if ((pl->flags & PL_RUNNING) != 0) {
794 pthread_mutex_unlock(&pl_lock);
797 pl->flags |= PL_RUNNING;
798 pthread_mutex_unlock(&pl_lock);
800 pthread_attr_init(&attr);
801 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
803 plugin_thread_create(&t, &attr, exec_read_one, (void *)pl, "exec read");
805 ERROR("exec plugin: plugin_thread_create failed.");
807 pthread_attr_destroy(&attr);
811 } /* int exec_read }}} */
813 static int exec_notification(const notification_t *n, /* {{{ */
814 user_data_t __attribute__((unused)) * user_data) {
815 program_list_and_notification_t *pln;
817 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next) {
821 /* Only execute `notification' style executables here. */
822 if ((pl->flags & PL_NOTIF_ACTION) == 0)
825 /* Skip if a child is already running. */
829 pln = malloc(sizeof(*pln));
831 ERROR("exec plugin: malloc failed.");
836 memcpy(&pln->n, n, sizeof(notification_t));
838 /* Set the `meta' member to NULL, otherwise `plugin_notification_meta_copy'
839 * will run into an endless loop. */
841 plugin_notification_meta_copy(&pln->n, n);
843 pthread_attr_init(&attr);
844 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
845 int status = plugin_thread_create(&t, &attr, exec_notification_one,
846 (void *)pln, "exec notify");
848 ERROR("exec plugin: plugin_thread_create failed.");
850 pthread_attr_destroy(&attr);
854 } /* }}} int exec_notification */
856 static int exec_shutdown(void) /* {{{ */
859 program_list_t *next;
866 kill(pl->pid, SIGTERM);
867 INFO("exec plugin: Sent SIGTERM to %hu", (unsigned short int)pl->pid);
878 } /* int exec_shutdown }}} */
880 void module_register(void) {
881 plugin_register_complex_config("exec", exec_config);
882 plugin_register_init("exec", exec_init);
883 plugin_register_read("exec", exec_read);
884 plugin_register_notification("exec", exec_notification,
885 /* user_data = */ NULL);
886 plugin_register_shutdown("exec", exec_shutdown);
887 } /* void module_register */