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;
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 static void set_environment(void) /* {{{ */
253 snprintf(buffer, sizeof(buffer), "%.3f",
254 CDTIME_T_TO_DOUBLE(plugin_get_interval()));
255 setenv("COLLECTD_INTERVAL", buffer, /* overwrite = */ 1);
257 sstrncpy(buffer, hostname_g, sizeof(buffer));
258 setenv("COLLECTD_HOSTNAME", buffer, /* overwrite = */ 1);
260 snprintf(buffer, sizeof(buffer), "COLLECTD_INTERVAL=%.3f",
261 CDTIME_T_TO_DOUBLE(plugin_get_interval()));
264 snprintf(buffer, sizeof(buffer), "COLLECTD_HOSTNAME=%s", hostname_g);
267 } /* }}} void set_environment */
269 __attribute__((noreturn)) static void exec_child(program_list_t *pl, int uid,
270 int gid, int egid) /* {{{ */
282 if ((gid != egid) && (egid != -1)) {
287 setgroups(glist_len, glist);
289 #endif /* HAVE_SETGROUPS */
291 status = setgid(gid);
293 ERROR("exec plugin: setgid (%i) failed: %s", gid, STRERRNO);
298 status = setegid(egid);
300 ERROR("exec plugin: setegid (%i) failed: %s", egid, STRERRNO);
305 status = setuid(uid);
307 ERROR("exec plugin: setuid (%i) failed: %s", uid, STRERRNO);
311 execvp(pl->exec, pl->argv);
313 ERROR("exec plugin: Failed to execute ``%s'': %s", pl->exec, STRERRNO);
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]) /* {{{ */
329 status = pipe(fd_pipe);
331 ERROR("exec plugin: pipe failed: %s", STRERRNO);
336 } /* }}} int create_pipe */
338 static void close_pipe(int fd_pipe[2]) /* {{{ */
340 if (fd_pipe[0] != -1)
343 if (fd_pipe[1] != -1)
345 } /* }}} void close_pipe */
348 * Get effective group ID from group name.
350 * pl :program list struct with group name
351 * gid :group id to fallback in case egid cannot be determined.
353 * egid effective group id if successfull,
354 * -1 if group is not defined/not found.
355 * -2 for any buffer allocation error.
357 static int getegr_id(program_list_t *pl, int gid) /* {{{ */
359 if (pl->group == NULL) {
362 if (strcmp(pl->group, "") == 0) {
365 struct group *gr_ptr = NULL;
368 long int grbuf_size = sysconf(_SC_GETGR_R_SIZE_MAX);
370 grbuf_size = sysconf(_SC_PAGESIZE);
378 temp = realloc(grbuf, grbuf_size);
380 ERROR("exec plugin: getegr_id for %s: realloc buffer[%ld] failed ",
381 pl->group, grbuf_size);
386 if (getgrnam_r(pl->group, &gr, grbuf, grbuf_size, &gr_ptr) == 0) {
388 if (gr_ptr == NULL) {
389 ERROR("exec plugin: No such group: `%s'", pl->group);
393 } else if (errno == ERANGE) {
394 grbuf_size += grbuf_size; // increment buffer size and try again
396 ERROR("exec plugin: getegr_id failed %s", STRERRNO);
400 } while (grbuf_size <= MAX_GRBUF_SIZE);
401 ERROR("exec plugin: getegr_id Max grbuf size reached for %s", pl->group);
407 * Creates three pipes (one for reading, one for writing and one for errors),
408 * forks a child, sets up the pipes so that fd_in is connected to STDIN of
409 * the child and fd_out is connected to STDOUT and fd_err is connected to STDERR
410 * of the child. Then is calls `exec_child'.
412 static int fork_child(program_list_t *pl, int *fd_in, int *fd_out,
413 int *fd_err) /* {{{ */
415 int fd_pipe_in[2] = {-1, -1};
416 int fd_pipe_out[2] = {-1, -1};
417 int fd_pipe_err[2] = {-1, -1};
425 struct passwd *sp_ptr;
431 long int nambuf_size = sysconf(_SC_GETPW_R_SIZE_MAX);
432 if (nambuf_size <= 0)
433 nambuf_size = sysconf(_SC_PAGESIZE);
434 if (nambuf_size <= 0)
436 char nambuf[nambuf_size];
438 if ((create_pipe(fd_pipe_in) == -1) || (create_pipe(fd_pipe_out) == -1) ||
439 (create_pipe(fd_pipe_err) == -1))
443 status = getpwnam_r(pl->user, &sp, nambuf, sizeof(nambuf), &sp_ptr);
445 ERROR("exec plugin: Failed to get user information for user ``%s'': %s",
446 pl->user, STRERROR(status));
450 if (sp_ptr == NULL) {
451 ERROR("exec plugin: No such user: `%s'", pl->user);
458 ERROR("exec plugin: Cowardly refusing to exec program as root.");
462 /* The group configured in the configfile is set as effective group, because
463 * this way the forked process can (re-)gain the user's primary group. */
464 egid = getegr_id(pl, gid);
471 ERROR("exec plugin: fork failed: %s", STRERRNO);
473 } else if (pid == 0) {
476 /* Close all file descriptors but the pipe end we need. */
477 fd_num = getdtablesize();
478 for (int fd = 0; fd < fd_num; fd++) {
479 if ((fd == fd_pipe_in[0]) || (fd == fd_pipe_out[1]) ||
480 (fd == fd_pipe_err[1]))
485 /* Connect the `in' pipe to STDIN */
486 if (fd_pipe_in[0] != STDIN_FILENO) {
487 dup2(fd_pipe_in[0], STDIN_FILENO);
488 close(fd_pipe_in[0]);
491 /* Now connect the `out' pipe to STDOUT */
492 if (fd_pipe_out[1] != STDOUT_FILENO) {
493 dup2(fd_pipe_out[1], STDOUT_FILENO);
494 close(fd_pipe_out[1]);
497 /* Now connect the `err' pipe to STDERR */
498 if (fd_pipe_err[1] != STDERR_FILENO) {
499 dup2(fd_pipe_err[1], STDERR_FILENO);
500 close(fd_pipe_err[1]);
505 /* Unblock all signals */
508 exec_child(pl, uid, gid, egid);
509 /* does not return */
512 close(fd_pipe_in[0]);
513 close(fd_pipe_out[1]);
514 close(fd_pipe_err[1]);
517 *fd_in = fd_pipe_in[1];
519 close(fd_pipe_in[1]);
522 *fd_out = fd_pipe_out[0];
524 close(fd_pipe_out[0]);
527 *fd_err = fd_pipe_err[0];
529 close(fd_pipe_err[0]);
534 close_pipe(fd_pipe_in);
535 close_pipe(fd_pipe_out);
536 close_pipe(fd_pipe_err);
539 } /* int fork_child }}} */
541 static int parse_line(char *buffer) /* {{{ */
543 if (strncasecmp("PUTVAL", buffer, strlen("PUTVAL")) == 0)
544 return cmd_handle_putval(stdout, buffer);
545 else if (strncasecmp("PUTNOTIF", buffer, strlen("PUTNOTIF")) == 0)
546 return handle_putnotif(stdout, buffer);
548 ERROR("exec plugin: Unable to parse command, ignoring line: \"%s\"",
552 } /* int parse_line }}} */
554 static void *exec_read_one(void *arg) /* {{{ */
556 program_list_t *pl = (program_list_t *)arg;
557 int fd, fd_err, highest_fd;
560 char buffer[1200]; /* if not completely read */
561 char buffer_err[1024];
562 char *pbuffer = buffer;
563 char *pbuffer_err = buffer_err;
565 status = fork_child(pl, NULL, &fd, &fd_err);
567 /* Reset the "running" flag */
568 pthread_mutex_lock(&pl_lock);
569 pl->flags &= ~PL_RUNNING;
570 pthread_mutex_unlock(&pl_lock);
571 pthread_exit((void *)1);
575 assert(pl->pid != 0);
579 FD_SET(fd_err, &fdset);
581 /* Determine the highest file descriptor */
582 highest_fd = (fd > fd_err) ? fd : fd_err;
584 /* We use a copy of fdset, as select modifies it */
590 status = select(highest_fd + 1, ©, NULL, NULL, NULL);
597 if (FD_ISSET(fd, ©)) {
600 len = read(fd, pbuffer, sizeof(buffer) - 1 - (pbuffer - buffer));
603 if (errno == EAGAIN || errno == EINTR)
607 break; /* We've reached EOF */
611 len += pbuffer - buffer;
614 while ((pnl = strchr(pbuffer, '\n'))) {
616 if (*(pnl - 1) == '\r')
623 /* not completely read ? */
624 if (pbuffer - buffer < len) {
625 len -= pbuffer - buffer;
626 memmove(buffer, pbuffer, len);
627 pbuffer = buffer + len;
630 } else if (FD_ISSET(fd_err, ©)) {
633 len = read(fd_err, pbuffer_err,
634 sizeof(buffer_err) - 1 - (pbuffer_err - buffer_err));
637 if (errno == EAGAIN || errno == EINTR)
640 } else if (len == 0) {
641 /* We've reached EOF */
642 NOTICE("exec plugin: Program `%s' has closed STDERR.", pl->exec);
644 /* Remove file descriptor form select() set. */
645 FD_CLR(fd_err, &fdset);
649 /* Clean up file descriptor */
655 pbuffer_err[len] = '\0';
657 len += pbuffer_err - buffer_err;
658 pbuffer_err = buffer_err;
660 while ((pnl = strchr(pbuffer_err, '\n'))) {
662 if (*(pnl - 1) == '\r')
665 ERROR("exec plugin: exec_read_one: error = %s", pbuffer_err);
669 /* not completely read ? */
670 if (pbuffer_err - buffer_err < len) {
671 len -= pbuffer_err - buffer_err;
672 memmove(buffer_err, pbuffer_err, len);
673 pbuffer_err = buffer_err + len;
675 pbuffer_err = buffer_err;
681 DEBUG("exec plugin: exec_read_one: Waiting for `%s' to exit.", pl->exec);
682 if (waitpid(pl->pid, &status, 0) > 0)
685 DEBUG("exec plugin: Child %i exited with status %i.", (int)pl->pid,
690 pthread_mutex_lock(&pl_lock);
691 pl->flags &= ~PL_RUNNING;
692 pthread_mutex_unlock(&pl_lock);
698 pthread_exit((void *)0);
700 } /* void *exec_read_one }}} */
702 static void *exec_notification_one(void *arg) /* {{{ */
704 program_list_t *pl = ((program_list_and_notification_t *)arg)->pl;
705 notification_t *n = &((program_list_and_notification_t *)arg)->n;
710 const char *severity;
712 pid = fork_child(pl, &fd, NULL, NULL);
715 pthread_exit((void *)1);
718 fh = fdopen(fd, "w");
720 ERROR("exec plugin: fdopen (%i) failed: %s", fd, STRERRNO);
724 pthread_exit((void *)1);
727 severity = "FAILURE";
728 if (n->severity == NOTIF_WARNING)
729 severity = "WARNING";
730 else if (n->severity == NOTIF_OKAY)
733 fprintf(fh, "Severity: %s\n"
735 severity, CDTIME_T_TO_DOUBLE(n->time));
737 /* Print the optional fields */
738 if (strlen(n->host) > 0)
739 fprintf(fh, "Host: %s\n", n->host);
740 if (strlen(n->plugin) > 0)
741 fprintf(fh, "Plugin: %s\n", n->plugin);
742 if (strlen(n->plugin_instance) > 0)
743 fprintf(fh, "PluginInstance: %s\n", n->plugin_instance);
744 if (strlen(n->type) > 0)
745 fprintf(fh, "Type: %s\n", n->type);
746 if (strlen(n->type_instance) > 0)
747 fprintf(fh, "TypeInstance: %s\n", n->type_instance);
749 for (notification_meta_t *meta = n->meta; meta != NULL; meta = meta->next) {
750 if (meta->type == NM_TYPE_STRING)
751 fprintf(fh, "%s: %s\n", meta->name, meta->nm_value.nm_string);
752 else if (meta->type == NM_TYPE_SIGNED_INT)
753 fprintf(fh, "%s: %" PRIi64 "\n", meta->name,
754 meta->nm_value.nm_signed_int);
755 else if (meta->type == NM_TYPE_UNSIGNED_INT)
756 fprintf(fh, "%s: %" PRIu64 "\n", meta->name,
757 meta->nm_value.nm_unsigned_int);
758 else if (meta->type == NM_TYPE_DOUBLE)
759 fprintf(fh, "%s: %e\n", meta->name, meta->nm_value.nm_double);
760 else if (meta->type == NM_TYPE_BOOLEAN)
761 fprintf(fh, "%s: %s\n", meta->name,
762 meta->nm_value.nm_boolean ? "true" : "false");
765 fprintf(fh, "\n%s\n", n->message);
770 waitpid(pid, &status, 0);
772 DEBUG("exec plugin: Child %i exited with status %i.", pid, status);
775 plugin_notification_meta_free(n->meta);
778 pthread_exit((void *)0);
780 } /* void *exec_notification_one }}} */
782 static int exec_init(void) /* {{{ */
784 struct sigaction sa = {.sa_handler = sigchld_handler};
786 sigaction(SIGCHLD, &sa, NULL);
788 #if defined(HAVE_SYS_CAPABILITY_H) && defined(CAP_SETUID) && defined(CAP_SETGID)
789 if ((check_capability(CAP_SETUID) != 0) ||
790 (check_capability(CAP_SETGID) != 0)) {
793 "exec plugin: Running collectd as root, but the CAP_SETUID "
794 "or CAP_SETGID capabilities are missing. The plugin's read function "
795 "will probably fail. Is your init system dropping capabilities?");
798 "exec plugin: collectd doesn't have the CAP_SETUID or "
799 "CAP_SETGID capabilities. If you don't want to run collectd as root, "
800 "try running \"setcap 'cap_setuid=ep cap_setgid=ep'\" on the "
806 } /* int exec_init }}} */
808 static int exec_read(void) /* {{{ */
810 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next) {
814 /* Only execute `normal' style executables here. */
815 if ((pl->flags & PL_NORMAL) == 0)
818 pthread_mutex_lock(&pl_lock);
819 /* Skip if a child is already running. */
820 if ((pl->flags & PL_RUNNING) != 0) {
821 pthread_mutex_unlock(&pl_lock);
824 pl->flags |= PL_RUNNING;
825 pthread_mutex_unlock(&pl_lock);
827 pthread_attr_init(&attr);
828 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
830 plugin_thread_create(&t, &attr, exec_read_one, (void *)pl, "exec read");
832 ERROR("exec plugin: plugin_thread_create failed.");
834 pthread_attr_destroy(&attr);
838 } /* int exec_read }}} */
840 static int exec_notification(const notification_t *n, /* {{{ */
841 user_data_t __attribute__((unused)) * user_data) {
842 program_list_and_notification_t *pln;
844 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next) {
848 /* Only execute `notification' style executables here. */
849 if ((pl->flags & PL_NOTIF_ACTION) == 0)
852 /* Skip if a child is already running. */
856 pln = malloc(sizeof(*pln));
858 ERROR("exec plugin: malloc failed.");
863 memcpy(&pln->n, n, sizeof(notification_t));
865 /* Set the `meta' member to NULL, otherwise `plugin_notification_meta_copy'
866 * will run into an endless loop. */
868 plugin_notification_meta_copy(&pln->n, n);
870 pthread_attr_init(&attr);
871 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
872 int status = plugin_thread_create(&t, &attr, exec_notification_one,
873 (void *)pln, "exec notify");
875 ERROR("exec plugin: plugin_thread_create failed.");
877 pthread_attr_destroy(&attr);
881 } /* }}} int exec_notification */
883 static int exec_shutdown(void) /* {{{ */
886 program_list_t *next;
893 kill(pl->pid, SIGTERM);
894 INFO("exec plugin: Sent SIGTERM to %hu", (unsigned short int)pl->pid);
905 } /* int exec_shutdown }}} */
907 void module_register(void) {
908 plugin_register_complex_config("exec", exec_config);
909 plugin_register_init("exec", exec_init);
910 plugin_register_read("exec", exec_read);
911 plugin_register_notification("exec", exec_notification,
912 /* user_data = */ NULL);
913 plugin_register_shutdown("exec", exec_shutdown);
914 } /* void module_register */