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 */
29 /* _GNU_SOURCE is needed in Linux to use execvpe */
35 #include "utils/common/common.h"
37 #include "utils/cmds/putnotif.h"
38 #include "utils/cmds/putval.h"
43 #include <sys/types.h>
45 #ifdef HAVE_SYS_CAPABILITY_H
46 #include <sys/capability.h>
49 extern char **environ;
51 #define PL_NORMAL 0x01
52 #define PL_NOTIF_ACTION 0x02
54 #define PL_RUNNING 0x10
60 * Access to this structure is serialized using the `pl_lock' lock and the
61 * `PL_RUNNING' flag. The execution of notifications is *not* serialized, so
62 * all functions used to handle notifications MUST NOT write to this structure.
63 * The `pid' and `status' fields are thus unused if the `PL_NOTIF_ACTION' flag
65 * The `PL_RUNNING' flag is set in `exec_read' and unset in `exec_read_one'.
67 struct program_list_s;
68 typedef struct program_list_s program_list_t;
69 struct program_list_s {
80 typedef struct program_list_and_notification_s {
83 } program_list_and_notification_t;
88 const long int MAX_GRBUF_SIZE = 65536;
93 static program_list_t *pl_head;
94 static pthread_mutex_t pl_lock = PTHREAD_MUTEX_INITIALIZER;
99 static void sigchld_handler(int __attribute__((unused)) signal) /* {{{ */
103 while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
105 for (pl = pl_head; pl != NULL; pl = pl->next)
110 } /* while (waitpid) */
111 } /* void sigchld_handler }}} */
113 static int exec_config_exec(oconfig_item_t *ci) /* {{{ */
119 if (ci->children_num != 0) {
120 WARNING("exec plugin: The config option `%s' may not be a block.", ci->key);
123 if (ci->values_num < 2) {
124 WARNING("exec plugin: The config option `%s' needs at least two "
129 if ((ci->values[0].type != OCONFIG_TYPE_STRING) ||
130 (ci->values[1].type != OCONFIG_TYPE_STRING)) {
131 WARNING("exec plugin: The first two arguments to the `%s' option must "
132 "be string arguments.",
137 pl = calloc(1, sizeof(*pl));
139 ERROR("exec plugin: calloc failed.");
143 if (strcasecmp("NotificationExec", ci->key) == 0)
144 pl->flags |= PL_NOTIF_ACTION;
146 pl->flags |= PL_NORMAL;
148 pl->user = strdup(ci->values[0].value.string);
149 if (pl->user == NULL) {
150 ERROR("exec plugin: strdup failed.");
155 pl->group = strchr(pl->user, ':');
156 if (pl->group != NULL) {
161 pl->exec = strdup(ci->values[1].value.string);
162 if (pl->exec == NULL) {
163 ERROR("exec plugin: strdup failed.");
169 pl->argv = calloc(ci->values_num, sizeof(*pl->argv));
170 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) {
187 ERROR("exec plugin: strdup failed.");
195 for (i = 1; i < (ci->values_num - 1); i++) {
196 if (ci->values[i + 1].type == OCONFIG_TYPE_STRING) {
197 pl->argv[i] = strdup(ci->values[i + 1].value.string);
199 if (ci->values[i + 1].type == OCONFIG_TYPE_NUMBER) {
200 snprintf(buffer, sizeof(buffer), "%lf", ci->values[i + 1].value.number);
202 if (ci->values[i + 1].value.boolean)
203 sstrncpy(buffer, "true", sizeof(buffer));
205 sstrncpy(buffer, "false", sizeof(buffer));
208 pl->argv[i] = strdup(buffer);
211 if (pl->argv[i] == NULL) {
212 ERROR("exec plugin: strdup failed.");
217 if (i < (ci->values_num - 1)) {
228 for (i = 0; pl->argv[i] != NULL; i++) {
229 DEBUG("exec plugin: argv[%i] = %s", i, pl->argv[i]);
236 } /* int exec_config_exec }}} */
238 static int exec_config(oconfig_item_t *ci) /* {{{ */
240 for (int i = 0; i < ci->children_num; i++) {
241 oconfig_item_t *child = ci->children + i;
242 if ((strcasecmp("Exec", child->key) == 0) ||
243 (strcasecmp("NotificationExec", child->key) == 0))
244 exec_config_exec(child);
246 WARNING("exec plugin: Unknown config option `%s'.", child->key);
251 } /* int exec_config }}} */
253 __attribute__((noreturn)) static void exec_child(program_list_t *pl,
254 char **envp, int uid, int gid,
267 if ((gid != egid) && (egid != -1)) {
272 setgroups(glist_len, glist);
274 #endif /* HAVE_SETGROUPS */
276 status = setgid(gid);
278 ERROR("exec plugin: setgid (%i) failed: %s", gid, STRERRNO);
283 status = setegid(egid);
285 ERROR("exec plugin: setegid (%i) failed: %s", egid, STRERRNO);
290 status = setuid(uid);
292 ERROR("exec plugin: setuid (%i) failed: %s", uid, STRERRNO);
297 execvpe(pl->exec, pl->argv, envp);
300 execvp(pl->exec, pl->argv);
303 ERROR("exec plugin: Failed to execute ``%s'': %s", pl->exec, STRERRNO);
305 } /* void exec_child }}} */
307 static void reset_signal_mask(void) /* {{{ */
312 sigprocmask(SIG_SETMASK, &ss, /* old mask = */ NULL);
313 } /* }}} void reset_signal_mask */
315 static int create_pipe(int fd_pipe[2]) /* {{{ */
319 status = pipe(fd_pipe);
321 ERROR("exec plugin: pipe failed: %s", STRERRNO);
326 } /* }}} int create_pipe */
328 static void close_pipe(int fd_pipe[2]) /* {{{ */
330 if (fd_pipe[0] != -1)
333 if (fd_pipe[1] != -1)
335 } /* }}} void close_pipe */
338 * Get effective group ID from group name.
340 * pl :program list struct with group name
341 * gid :group id to fallback in case egid cannot be determined.
343 * egid effective group id if successfull,
344 * -1 if group is not defined/not found.
345 * -2 for any buffer allocation error.
347 static int getegr_id(program_list_t *pl, int gid) /* {{{ */
349 if (pl->group == NULL) {
352 if (strcmp(pl->group, "") == 0) {
355 struct group *gr_ptr = NULL;
358 long int grbuf_size = sysconf(_SC_GETGR_R_SIZE_MAX);
360 grbuf_size = sysconf(_SC_PAGESIZE);
368 temp = realloc(grbuf, grbuf_size);
370 ERROR("exec plugin: getegr_id for %s: realloc buffer[%ld] failed ",
371 pl->group, grbuf_size);
376 if (getgrnam_r(pl->group, &gr, grbuf, grbuf_size, &gr_ptr) == 0) {
378 if (gr_ptr == NULL) {
379 ERROR("exec plugin: No such group: `%s'", pl->group);
383 } else if (errno == ERANGE) {
384 grbuf_size += grbuf_size; // increment buffer size and try again
386 ERROR("exec plugin: getegr_id failed %s", STRERRNO);
390 } while (grbuf_size <= MAX_GRBUF_SIZE);
391 ERROR("exec plugin: getegr_id Max grbuf size reached for %s", pl->group);
397 * Creates three pipes (one for reading, one for writing and one for errors),
398 * forks a child, sets up the pipes so that fd_in is connected to STDIN of
399 * the child and fd_out is connected to STDOUT and fd_err is connected to STDERR
400 * of the child. Then is calls `exec_child'.
402 static int fork_child(program_list_t *pl, int *fd_in, int *fd_out,
403 int *fd_err) /* {{{ */
405 int fd_pipe_in[2] = {-1, -1};
406 int fd_pipe_out[2] = {-1, -1};
407 int fd_pipe_err[2] = {-1, -1};
415 struct passwd *sp_ptr;
421 long int nambuf_size = sysconf(_SC_GETPW_R_SIZE_MAX);
422 if (nambuf_size <= 0)
423 nambuf_size = sysconf(_SC_PAGESIZE);
424 if (nambuf_size <= 0)
426 char nambuf[nambuf_size];
428 if ((create_pipe(fd_pipe_in) == -1) || (create_pipe(fd_pipe_out) == -1) ||
429 (create_pipe(fd_pipe_err) == -1))
433 status = getpwnam_r(pl->user, &sp, nambuf, sizeof(nambuf), &sp_ptr);
435 ERROR("exec plugin: Failed to get user information for user ``%s'': %s",
436 pl->user, STRERROR(status));
440 if (sp_ptr == NULL) {
441 ERROR("exec plugin: No such user: `%s'", pl->user);
448 ERROR("exec plugin: Cowardly refusing to exec program as root.");
452 /* The group configured in the configfile is set as effective group, because
453 * this way the forked process can (re-)gain the user's primary group. */
454 egid = getegr_id(pl, gid);
459 double interval = CDTIME_T_TO_DOUBLE(plugin_get_interval());
463 ERROR("exec plugin: fork failed: %s", STRERRNO);
465 } else if (pid == 0) {
466 char interval_buf[128];
467 snprintf(interval_buf, sizeof(interval_buf), "COLLECTD_INTERVAL=%.3f",
470 /* max hostname len is 255, so this should be enough */
471 char hostname_buf[300];
472 snprintf(hostname_buf, sizeof(hostname_buf), "COLLECTD_HOSTNAME=%s",
476 while (environ[env_size] != NULL) {
480 /* Copy the environment variables */
481 char *envp[env_size + 3];
483 for (envp_idx = 0; environ[envp_idx] != NULL && envp_idx < env_size;
485 envp[envp_idx] = environ[envp_idx];
488 /* Add the collectd environment variables */
489 envp[envp_idx++] = interval_buf;
490 envp[envp_idx++] = hostname_buf;
491 envp[envp_idx++] = NULL;
493 /* Close all file descriptors but the pipe end we need. */
494 int fd_num = getdtablesize();
495 for (int fd = 0; fd < fd_num; fd++) {
496 if ((fd == fd_pipe_in[0]) || (fd == fd_pipe_out[1]) ||
497 (fd == fd_pipe_err[1]))
502 /* Connect the `in' pipe to STDIN */
503 if (fd_pipe_in[0] != STDIN_FILENO) {
504 dup2(fd_pipe_in[0], STDIN_FILENO);
505 close(fd_pipe_in[0]);
508 /* Now connect the `out' pipe to STDOUT */
509 if (fd_pipe_out[1] != STDOUT_FILENO) {
510 dup2(fd_pipe_out[1], STDOUT_FILENO);
511 close(fd_pipe_out[1]);
514 /* Now connect the `err' pipe to STDERR */
515 if (fd_pipe_err[1] != STDERR_FILENO) {
516 dup2(fd_pipe_err[1], STDERR_FILENO);
517 close(fd_pipe_err[1]);
520 /* Unblock all signals */
523 exec_child(pl, envp, uid, gid, egid);
524 /* does not return */
527 close(fd_pipe_in[0]);
528 close(fd_pipe_out[1]);
529 close(fd_pipe_err[1]);
532 *fd_in = fd_pipe_in[1];
534 close(fd_pipe_in[1]);
537 *fd_out = fd_pipe_out[0];
539 close(fd_pipe_out[0]);
542 *fd_err = fd_pipe_err[0];
544 close(fd_pipe_err[0]);
549 close_pipe(fd_pipe_in);
550 close_pipe(fd_pipe_out);
551 close_pipe(fd_pipe_err);
554 } /* int fork_child }}} */
556 static int parse_line(char *buffer) /* {{{ */
558 if (strncasecmp("PUTVAL", buffer, strlen("PUTVAL")) == 0)
559 return cmd_handle_putval(stdout, buffer);
560 else if (strncasecmp("PUTNOTIF", buffer, strlen("PUTNOTIF")) == 0)
561 return handle_putnotif(stdout, buffer);
563 ERROR("exec plugin: Unable to parse command, ignoring line: \"%s\"",
567 } /* int parse_line }}} */
569 static void *exec_read_one(void *arg) /* {{{ */
571 program_list_t *pl = (program_list_t *)arg;
572 int fd, fd_err, highest_fd;
575 char buffer[1200]; /* if not completely read */
576 char buffer_err[1024];
577 char *pbuffer = buffer;
578 char *pbuffer_err = buffer_err;
580 status = fork_child(pl, NULL, &fd, &fd_err);
582 /* Reset the "running" flag */
583 pthread_mutex_lock(&pl_lock);
584 pl->flags &= ~PL_RUNNING;
585 pthread_mutex_unlock(&pl_lock);
586 pthread_exit((void *)1);
590 assert(pl->pid != 0);
594 FD_SET(fd_err, &fdset);
596 /* Determine the highest file descriptor */
597 highest_fd = (fd > fd_err) ? fd : fd_err;
599 /* We use a copy of fdset, as select modifies it */
605 status = select(highest_fd + 1, ©, NULL, NULL, NULL);
612 if (FD_ISSET(fd, ©)) {
615 len = read(fd, pbuffer, sizeof(buffer) - 1 - (pbuffer - buffer));
618 if (errno == EAGAIN || errno == EINTR)
622 break; /* We've reached EOF */
626 len += pbuffer - buffer;
629 while ((pnl = strchr(pbuffer, '\n'))) {
631 if (*(pnl - 1) == '\r')
638 /* not completely read ? */
639 if (pbuffer - buffer < len) {
640 len -= pbuffer - buffer;
641 memmove(buffer, pbuffer, len);
642 pbuffer = buffer + len;
645 } else if (FD_ISSET(fd_err, ©)) {
648 len = read(fd_err, pbuffer_err,
649 sizeof(buffer_err) - 1 - (pbuffer_err - buffer_err));
652 if (errno == EAGAIN || errno == EINTR)
655 } else if (len == 0) {
656 /* We've reached EOF */
657 NOTICE("exec plugin: Program `%s' has closed STDERR.", pl->exec);
659 /* Remove file descriptor form select() set. */
660 FD_CLR(fd_err, &fdset);
664 /* Clean up file descriptor */
670 pbuffer_err[len] = '\0';
672 len += pbuffer_err - buffer_err;
673 pbuffer_err = buffer_err;
675 while ((pnl = strchr(pbuffer_err, '\n'))) {
677 if (*(pnl - 1) == '\r')
680 ERROR("exec plugin: exec_read_one: error = %s", pbuffer_err);
684 /* not completely read ? */
685 if (pbuffer_err - buffer_err < len) {
686 len -= pbuffer_err - buffer_err;
687 memmove(buffer_err, pbuffer_err, len);
688 pbuffer_err = buffer_err + len;
690 pbuffer_err = buffer_err;
696 DEBUG("exec plugin: exec_read_one: Waiting for `%s' to exit.", pl->exec);
697 if (waitpid(pl->pid, &status, 0) > 0)
700 DEBUG("exec plugin: Child %i exited with status %i.", (int)pl->pid,
705 pthread_mutex_lock(&pl_lock);
706 pl->flags &= ~PL_RUNNING;
707 pthread_mutex_unlock(&pl_lock);
713 pthread_exit((void *)0);
715 } /* void *exec_read_one }}} */
717 static void *exec_notification_one(void *arg) /* {{{ */
719 program_list_t *pl = ((program_list_and_notification_t *)arg)->pl;
720 notification_t *n = &((program_list_and_notification_t *)arg)->n;
725 const char *severity;
727 pid = fork_child(pl, &fd, NULL, NULL);
730 pthread_exit((void *)1);
733 fh = fdopen(fd, "w");
735 ERROR("exec plugin: fdopen (%i) failed: %s", fd, STRERRNO);
739 pthread_exit((void *)1);
742 severity = "FAILURE";
743 if (n->severity == NOTIF_WARNING)
744 severity = "WARNING";
745 else if (n->severity == NOTIF_OKAY)
751 severity, CDTIME_T_TO_DOUBLE(n->time));
753 /* Print the optional fields */
754 if (strlen(n->host) > 0)
755 fprintf(fh, "Host: %s\n", n->host);
756 if (strlen(n->plugin) > 0)
757 fprintf(fh, "Plugin: %s\n", n->plugin);
758 if (strlen(n->plugin_instance) > 0)
759 fprintf(fh, "PluginInstance: %s\n", n->plugin_instance);
760 if (strlen(n->type) > 0)
761 fprintf(fh, "Type: %s\n", n->type);
762 if (strlen(n->type_instance) > 0)
763 fprintf(fh, "TypeInstance: %s\n", n->type_instance);
765 for (notification_meta_t *meta = n->meta; meta != NULL; meta = meta->next) {
766 if (meta->type == NM_TYPE_STRING)
767 fprintf(fh, "%s: %s\n", meta->name, meta->nm_value.nm_string);
768 else if (meta->type == NM_TYPE_SIGNED_INT)
769 fprintf(fh, "%s: %" PRIi64 "\n", meta->name,
770 meta->nm_value.nm_signed_int);
771 else if (meta->type == NM_TYPE_UNSIGNED_INT)
772 fprintf(fh, "%s: %" PRIu64 "\n", meta->name,
773 meta->nm_value.nm_unsigned_int);
774 else if (meta->type == NM_TYPE_DOUBLE)
775 fprintf(fh, "%s: %e\n", meta->name, meta->nm_value.nm_double);
776 else if (meta->type == NM_TYPE_BOOLEAN)
777 fprintf(fh, "%s: %s\n", meta->name,
778 meta->nm_value.nm_boolean ? "true" : "false");
781 fprintf(fh, "\n%s\n", n->message);
786 waitpid(pid, &status, 0);
788 DEBUG("exec plugin: Child %i exited with status %i.", pid, status);
791 plugin_notification_meta_free(n->meta);
794 pthread_exit((void *)0);
796 } /* void *exec_notification_one }}} */
798 static int exec_init(void) /* {{{ */
800 struct sigaction sa = {.sa_handler = sigchld_handler};
802 sigaction(SIGCHLD, &sa, NULL);
804 #if defined(HAVE_SYS_CAPABILITY_H) && defined(CAP_SETUID) && defined(CAP_SETGID)
805 if ((check_capability(CAP_SETUID) != 0) ||
806 (check_capability(CAP_SETGID) != 0)) {
809 "exec plugin: Running collectd as root, but the CAP_SETUID "
810 "or CAP_SETGID capabilities are missing. The plugin's read function "
811 "will probably fail. Is your init system dropping capabilities?");
814 "exec plugin: collectd doesn't have the CAP_SETUID or "
815 "CAP_SETGID capabilities. If you don't want to run collectd as root, "
816 "try running \"setcap 'cap_setuid=ep cap_setgid=ep'\" on the "
822 } /* int exec_init }}} */
824 static int exec_read(void) /* {{{ */
826 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next) {
830 /* Only execute `normal' style executables here. */
831 if ((pl->flags & PL_NORMAL) == 0)
834 pthread_mutex_lock(&pl_lock);
835 /* Skip if a child is already running. */
836 if ((pl->flags & PL_RUNNING) != 0) {
837 pthread_mutex_unlock(&pl_lock);
840 pl->flags |= PL_RUNNING;
841 pthread_mutex_unlock(&pl_lock);
843 pthread_attr_init(&attr);
844 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
846 plugin_thread_create(&t, &attr, exec_read_one, (void *)pl, "exec read");
848 ERROR("exec plugin: plugin_thread_create failed.");
850 pthread_attr_destroy(&attr);
854 } /* int exec_read }}} */
856 static int exec_notification(const notification_t *n, /* {{{ */
857 user_data_t __attribute__((unused)) * user_data) {
858 program_list_and_notification_t *pln;
860 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next) {
864 /* Only execute `notification' style executables here. */
865 if ((pl->flags & PL_NOTIF_ACTION) == 0)
868 /* Skip if a child is already running. */
872 pln = malloc(sizeof(*pln));
874 ERROR("exec plugin: malloc failed.");
879 memcpy(&pln->n, n, sizeof(notification_t));
881 /* Set the `meta' member to NULL, otherwise `plugin_notification_meta_copy'
882 * will run into an endless loop. */
884 plugin_notification_meta_copy(&pln->n, n);
886 pthread_attr_init(&attr);
887 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
888 int status = plugin_thread_create(&t, &attr, exec_notification_one,
889 (void *)pln, "exec notify");
891 ERROR("exec plugin: plugin_thread_create failed.");
893 pthread_attr_destroy(&attr);
897 } /* }}} int exec_notification */
899 static int exec_shutdown(void) /* {{{ */
902 program_list_t *next;
909 kill(pl->pid, SIGTERM);
910 INFO("exec plugin: Sent SIGTERM to %hu", (unsigned short int)pl->pid);
913 for (int i = 0; pl->argv[i] != NULL; i++) {
926 } /* int exec_shutdown }}} */
928 void module_register(void) {
929 plugin_register_complex_config("exec", exec_config);
930 plugin_register_init("exec", exec_init);
931 plugin_register_read("exec", exec_read);
932 plugin_register_notification("exec", exec_notification,
933 /* user_data = */ NULL);
934 plugin_register_shutdown("exec", exec_shutdown);
935 } /* void module_register */