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>
43 #ifdef HAVE_SYS_CAPABILITY_H
44 #include <sys/capability.h>
47 #define PL_NORMAL 0x01
48 #define PL_NOTIF_ACTION 0x02
50 #define PL_RUNNING 0x10
56 * Access to this structure is serialized using the `pl_lock' lock and the
57 * `PL_RUNNING' flag. The execution of notifications is *not* serialized, so
58 * all functions used to handle notifications MUST NOT write to this structure.
59 * The `pid' and `status' fields are thus unused if the `PL_NOTIF_ACTION' flag
61 * The `PL_RUNNING' flag is set in `exec_read' and unset in `exec_read_one'.
63 struct program_list_s;
64 typedef struct program_list_s program_list_t;
65 struct program_list_s {
76 typedef struct program_list_and_notification_s {
79 } program_list_and_notification_t;
84 const long int MAX_GRBUF_SIZE = 65536;
89 static program_list_t *pl_head;
90 static pthread_mutex_t pl_lock = PTHREAD_MUTEX_INITIALIZER;
95 static void sigchld_handler(int __attribute__((unused)) signal) /* {{{ */
99 while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
101 for (pl = pl_head; pl != NULL; pl = pl->next)
106 } /* while (waitpid) */
107 } /* void sigchld_handler }}} */
109 static int exec_config_exec(oconfig_item_t *ci) /* {{{ */
115 if (ci->children_num != 0) {
116 WARNING("exec plugin: The config option `%s' may not be a block.", ci->key);
119 if (ci->values_num < 2) {
120 WARNING("exec plugin: The config option `%s' needs at least two "
125 if ((ci->values[0].type != OCONFIG_TYPE_STRING) ||
126 (ci->values[1].type != OCONFIG_TYPE_STRING)) {
127 WARNING("exec plugin: The first two arguments to the `%s' option must "
128 "be string arguments.",
133 pl = calloc(1, sizeof(*pl));
135 ERROR("exec plugin: calloc failed.");
139 if (strcasecmp("NotificationExec", ci->key) == 0)
140 pl->flags |= PL_NOTIF_ACTION;
142 pl->flags |= PL_NORMAL;
144 pl->user = strdup(ci->values[0].value.string);
145 if (pl->user == NULL) {
146 ERROR("exec plugin: strdup failed.");
151 pl->group = strchr(pl->user, ':');
152 if (pl->group != NULL) {
157 pl->exec = strdup(ci->values[1].value.string);
158 if (pl->exec == NULL) {
159 ERROR("exec plugin: strdup failed.");
165 pl->argv = calloc(ci->values_num, sizeof(*pl->argv));
166 if (pl->argv == NULL) {
167 ERROR("exec plugin: calloc failed.");
175 char *tmp = strrchr(ci->values[1].value.string, '/');
177 sstrncpy(buffer, ci->values[1].value.string, sizeof(buffer));
179 sstrncpy(buffer, tmp + 1, sizeof(buffer));
181 pl->argv[0] = strdup(buffer);
182 if (pl->argv[0] == NULL) {
183 ERROR("exec plugin: strdup failed.");
191 for (i = 1; i < (ci->values_num - 1); i++) {
192 if (ci->values[i + 1].type == OCONFIG_TYPE_STRING) {
193 pl->argv[i] = strdup(ci->values[i + 1].value.string);
195 if (ci->values[i + 1].type == OCONFIG_TYPE_NUMBER) {
196 snprintf(buffer, sizeof(buffer), "%lf", ci->values[i + 1].value.number);
198 if (ci->values[i + 1].value.boolean)
199 sstrncpy(buffer, "true", sizeof(buffer));
201 sstrncpy(buffer, "false", sizeof(buffer));
204 pl->argv[i] = strdup(buffer);
207 if (pl->argv[i] == NULL) {
208 ERROR("exec plugin: strdup failed.");
213 if (i < (ci->values_num - 1)) {
224 for (i = 0; pl->argv[i] != NULL; i++) {
225 DEBUG("exec plugin: argv[%i] = %s", i, pl->argv[i]);
232 } /* int exec_config_exec }}} */
234 static int exec_config(oconfig_item_t *ci) /* {{{ */
236 for (int i = 0; i < ci->children_num; i++) {
237 oconfig_item_t *child = ci->children + i;
238 if ((strcasecmp("Exec", child->key) == 0) ||
239 (strcasecmp("NotificationExec", child->key) == 0))
240 exec_config_exec(child);
242 WARNING("exec plugin: Unknown config option `%s'.", child->key);
247 } /* int exec_config }}} */
249 static void set_environment(void) /* {{{ */
254 snprintf(buffer, sizeof(buffer), "%.3f",
255 CDTIME_T_TO_DOUBLE(plugin_get_interval()));
256 setenv("COLLECTD_INTERVAL", buffer, /* overwrite = */ 1);
258 sstrncpy(buffer, hostname_g, sizeof(buffer));
259 setenv("COLLECTD_HOSTNAME", buffer, /* overwrite = */ 1);
261 snprintf(buffer, sizeof(buffer), "COLLECTD_INTERVAL=%.3f",
262 CDTIME_T_TO_DOUBLE(plugin_get_interval()));
265 snprintf(buffer, sizeof(buffer), "COLLECTD_HOSTNAME=%s", hostname_g);
268 } /* }}} void set_environment */
270 __attribute__((noreturn)) static void exec_child(program_list_t *pl, int uid,
271 int gid, int egid) /* {{{ */
283 if ((gid != egid) && (egid != -1)) {
288 setgroups(glist_len, glist);
290 #endif /* HAVE_SETGROUPS */
292 status = setgid(gid);
294 ERROR("exec plugin: setgid (%i) failed: %s", gid, STRERRNO);
299 status = setegid(egid);
301 ERROR("exec plugin: setegid (%i) failed: %s", egid, STRERRNO);
306 status = setuid(uid);
308 ERROR("exec plugin: setuid (%i) failed: %s", uid, STRERRNO);
312 execvp(pl->exec, pl->argv);
314 ERROR("exec plugin: Failed to execute ``%s'': %s", pl->exec, STRERRNO);
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]) /* {{{ */
330 status = pipe(fd_pipe);
332 ERROR("exec plugin: pipe failed: %s", STRERRNO);
337 } /* }}} int create_pipe */
339 static void close_pipe(int fd_pipe[2]) /* {{{ */
341 if (fd_pipe[0] != -1)
344 if (fd_pipe[1] != -1)
346 } /* }}} void close_pipe */
349 * Get effective group ID from group name.
351 static int getegid(program_list_t *pl) {
353 if (pl->group != NULL) {
354 if (*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 int getgr_failed = 0;
369 grbuf = malloc(size);
371 ERROR("exec plugin: get group information for '%s' failed: buffer "
378 while ((status = getgrnam_r(pl->group, &gr, grbuf, size, &gr_ptr)) != 0) {
381 if ((size + grbuf_size) < size ||
382 (size + grbuf_size) > MAX_GRBUF_SIZE) {
383 ERROR("exec plugin: get group information for '%s' max buffer "
384 "limit (%ld) reached \n",
385 pl->group, MAX_GRBUF_SIZE);
389 /* grow the buffer by 'grbuf_size' each time getgrnamr fails */
391 temp = realloc(grbuf, size);
393 ERROR("exec plugin: get group information for '%s' realloc() "
394 "buffer to (%ld) failed ",
402 ERROR("exec plugin: default errno: get group information for '%s' "
404 pl->group, STRERRNO);
409 if (gr_ptr == NULL) {
410 ERROR("exec plugin: No such group: `%s'", pl->group);
417 DEBUG("exec plugin: release grbuf memory ");
419 if (getgr_failed > 0) {
425 } /* if (pl->group == NULL) */
430 * Creates three pipes (one for reading, one for writing and one for errors),
431 * forks a child, sets up the pipes so that fd_in is connected to STDIN of
432 * the child and fd_out is connected to STDOUT and fd_err is connected to STDERR
433 * of the child. Then is calls `exec_child'.
435 static int fork_child(program_list_t *pl, int *fd_in, int *fd_out,
436 int *fd_err) /* {{{ */
438 int fd_pipe_in[2] = {-1, -1};
439 int fd_pipe_out[2] = {-1, -1};
440 int fd_pipe_err[2] = {-1, -1};
448 struct passwd *sp_ptr;
454 long int nambuf_size = sysconf(_SC_GETPW_R_SIZE_MAX);
455 if (nambuf_size <= 0)
456 nambuf_size = sysconf(_SC_PAGESIZE);
457 if (nambuf_size <= 0)
459 char nambuf[nambuf_size];
461 if ((create_pipe(fd_pipe_in) == -1) || (create_pipe(fd_pipe_out) == -1) ||
462 (create_pipe(fd_pipe_err) == -1))
466 status = getpwnam_r(pl->user, &sp, nambuf, sizeof(nambuf), &sp_ptr);
468 ERROR("exec plugin: Failed to get user information for user ``%s'': %s",
469 pl->user, STRERROR(status));
473 if (sp_ptr == NULL) {
474 ERROR("exec plugin: No such user: `%s'", pl->user);
481 ERROR("exec plugin: Cowardly refusing to exec program as root.");
485 /* The group configured in the configfile is set as effective group, because
486 * this way the forked process can (re-)gain the user's primary group. */
491 ERROR("exec plugin: fork failed: %s", STRERRNO);
493 } else if (pid == 0) {
496 /* Close all file descriptors but the pipe end we need. */
497 fd_num = getdtablesize();
498 for (int fd = 0; fd < fd_num; fd++) {
499 if ((fd == fd_pipe_in[0]) || (fd == fd_pipe_out[1]) ||
500 (fd == fd_pipe_err[1]))
505 /* Connect the `in' pipe to STDIN */
506 if (fd_pipe_in[0] != STDIN_FILENO) {
507 dup2(fd_pipe_in[0], STDIN_FILENO);
508 close(fd_pipe_in[0]);
511 /* Now connect the `out' pipe to STDOUT */
512 if (fd_pipe_out[1] != STDOUT_FILENO) {
513 dup2(fd_pipe_out[1], STDOUT_FILENO);
514 close(fd_pipe_out[1]);
517 /* Now connect the `err' pipe to STDERR */
518 if (fd_pipe_err[1] != STDERR_FILENO) {
519 dup2(fd_pipe_err[1], STDERR_FILENO);
520 close(fd_pipe_err[1]);
525 /* Unblock all signals */
528 exec_child(pl, uid, gid, egid);
529 /* does not return */
532 close(fd_pipe_in[0]);
533 close(fd_pipe_out[1]);
534 close(fd_pipe_err[1]);
537 *fd_in = fd_pipe_in[1];
539 close(fd_pipe_in[1]);
542 *fd_out = fd_pipe_out[0];
544 close(fd_pipe_out[0]);
547 *fd_err = fd_pipe_err[0];
549 close(fd_pipe_err[0]);
554 close_pipe(fd_pipe_in);
555 close_pipe(fd_pipe_out);
556 close_pipe(fd_pipe_err);
559 } /* int fork_child }}} */
561 static int parse_line(char *buffer) /* {{{ */
563 if (strncasecmp("PUTVAL", buffer, strlen("PUTVAL")) == 0)
564 return cmd_handle_putval(stdout, buffer);
565 else if (strncasecmp("PUTNOTIF", buffer, strlen("PUTNOTIF")) == 0)
566 return handle_putnotif(stdout, buffer);
568 ERROR("exec plugin: Unable to parse command, ignoring line: \"%s\"",
572 } /* int parse_line }}} */
574 static void *exec_read_one(void *arg) /* {{{ */
576 program_list_t *pl = (program_list_t *)arg;
577 int fd, fd_err, highest_fd;
580 char buffer[1200]; /* if not completely read */
581 char buffer_err[1024];
582 char *pbuffer = buffer;
583 char *pbuffer_err = buffer_err;
585 status = fork_child(pl, NULL, &fd, &fd_err);
587 /* Reset the "running" flag */
588 pthread_mutex_lock(&pl_lock);
589 pl->flags &= ~PL_RUNNING;
590 pthread_mutex_unlock(&pl_lock);
591 pthread_exit((void *)1);
595 assert(pl->pid != 0);
599 FD_SET(fd_err, &fdset);
601 /* Determine the highest file descriptor */
602 highest_fd = (fd > fd_err) ? fd : fd_err;
604 /* We use a copy of fdset, as select modifies it */
610 status = select(highest_fd + 1, ©, NULL, NULL, NULL);
617 if (FD_ISSET(fd, ©)) {
620 len = read(fd, pbuffer, sizeof(buffer) - 1 - (pbuffer - buffer));
623 if (errno == EAGAIN || errno == EINTR)
627 break; /* We've reached EOF */
631 len += pbuffer - buffer;
634 while ((pnl = strchr(pbuffer, '\n'))) {
636 if (*(pnl - 1) == '\r')
643 /* not completely read ? */
644 if (pbuffer - buffer < len) {
645 len -= pbuffer - buffer;
646 memmove(buffer, pbuffer, len);
647 pbuffer = buffer + len;
650 } else if (FD_ISSET(fd_err, ©)) {
653 len = read(fd_err, pbuffer_err,
654 sizeof(buffer_err) - 1 - (pbuffer_err - buffer_err));
657 if (errno == EAGAIN || errno == EINTR)
660 } else if (len == 0) {
661 /* We've reached EOF */
662 NOTICE("exec plugin: Program `%s' has closed STDERR.", pl->exec);
664 /* Remove file descriptor form select() set. */
665 FD_CLR(fd_err, &fdset);
669 /* Clean up file descriptor */
675 pbuffer_err[len] = '\0';
677 len += pbuffer_err - buffer_err;
678 pbuffer_err = buffer_err;
680 while ((pnl = strchr(pbuffer_err, '\n'))) {
682 if (*(pnl - 1) == '\r')
685 ERROR("exec plugin: exec_read_one: error = %s", pbuffer_err);
689 /* not completely read ? */
690 if (pbuffer_err - buffer_err < len) {
691 len -= pbuffer_err - buffer_err;
692 memmove(buffer_err, pbuffer_err, len);
693 pbuffer_err = buffer_err + len;
695 pbuffer_err = buffer_err;
701 DEBUG("exec plugin: exec_read_one: Waiting for `%s' to exit.", pl->exec);
702 if (waitpid(pl->pid, &status, 0) > 0)
705 DEBUG("exec plugin: Child %i exited with status %i.", (int)pl->pid,
710 pthread_mutex_lock(&pl_lock);
711 pl->flags &= ~PL_RUNNING;
712 pthread_mutex_unlock(&pl_lock);
718 pthread_exit((void *)0);
720 } /* void *exec_read_one }}} */
722 static void *exec_notification_one(void *arg) /* {{{ */
724 program_list_t *pl = ((program_list_and_notification_t *)arg)->pl;
725 notification_t *n = &((program_list_and_notification_t *)arg)->n;
730 const char *severity;
732 pid = fork_child(pl, &fd, NULL, NULL);
735 pthread_exit((void *)1);
738 fh = fdopen(fd, "w");
740 ERROR("exec plugin: fdopen (%i) failed: %s", fd, STRERRNO);
744 pthread_exit((void *)1);
747 severity = "FAILURE";
748 if (n->severity == NOTIF_WARNING)
749 severity = "WARNING";
750 else if (n->severity == NOTIF_OKAY)
753 fprintf(fh, "Severity: %s\n"
755 severity, CDTIME_T_TO_DOUBLE(n->time));
757 /* Print the optional fields */
758 if (strlen(n->host) > 0)
759 fprintf(fh, "Host: %s\n", n->host);
760 if (strlen(n->plugin) > 0)
761 fprintf(fh, "Plugin: %s\n", n->plugin);
762 if (strlen(n->plugin_instance) > 0)
763 fprintf(fh, "PluginInstance: %s\n", n->plugin_instance);
764 if (strlen(n->type) > 0)
765 fprintf(fh, "Type: %s\n", n->type);
766 if (strlen(n->type_instance) > 0)
767 fprintf(fh, "TypeInstance: %s\n", n->type_instance);
769 for (notification_meta_t *meta = n->meta; meta != NULL; meta = meta->next) {
770 if (meta->type == NM_TYPE_STRING)
771 fprintf(fh, "%s: %s\n", meta->name, meta->nm_value.nm_string);
772 else if (meta->type == NM_TYPE_SIGNED_INT)
773 fprintf(fh, "%s: %" PRIi64 "\n", meta->name,
774 meta->nm_value.nm_signed_int);
775 else if (meta->type == NM_TYPE_UNSIGNED_INT)
776 fprintf(fh, "%s: %" PRIu64 "\n", meta->name,
777 meta->nm_value.nm_unsigned_int);
778 else if (meta->type == NM_TYPE_DOUBLE)
779 fprintf(fh, "%s: %e\n", meta->name, meta->nm_value.nm_double);
780 else if (meta->type == NM_TYPE_BOOLEAN)
781 fprintf(fh, "%s: %s\n", meta->name,
782 meta->nm_value.nm_boolean ? "true" : "false");
785 fprintf(fh, "\n%s\n", n->message);
790 waitpid(pid, &status, 0);
792 DEBUG("exec plugin: Child %i exited with status %i.", pid, status);
795 plugin_notification_meta_free(n->meta);
798 pthread_exit((void *)0);
800 } /* void *exec_notification_one }}} */
802 static int exec_init(void) /* {{{ */
804 struct sigaction sa = {.sa_handler = sigchld_handler};
806 sigaction(SIGCHLD, &sa, NULL);
808 #if defined(HAVE_SYS_CAPABILITY_H) && defined(CAP_SETUID) && defined(CAP_SETGID)
809 if ((check_capability(CAP_SETUID) != 0) ||
810 (check_capability(CAP_SETGID) != 0)) {
813 "exec plugin: Running collectd as root, but the CAP_SETUID "
814 "or CAP_SETGID capabilities are missing. The plugin's read function "
815 "will probably fail. Is your init system dropping capabilities?");
818 "exec plugin: collectd doesn't have the CAP_SETUID or "
819 "CAP_SETGID capabilities. If you don't want to run collectd as root, "
820 "try running \"setcap 'cap_setuid=ep cap_setgid=ep'\" on the "
826 } /* int exec_init }}} */
828 static int exec_read(void) /* {{{ */
830 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next) {
834 /* Only execute `normal' style executables here. */
835 if ((pl->flags & PL_NORMAL) == 0)
838 pthread_mutex_lock(&pl_lock);
839 /* Skip if a child is already running. */
840 if ((pl->flags & PL_RUNNING) != 0) {
841 pthread_mutex_unlock(&pl_lock);
844 pl->flags |= PL_RUNNING;
845 pthread_mutex_unlock(&pl_lock);
847 pthread_attr_init(&attr);
848 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
850 plugin_thread_create(&t, &attr, exec_read_one, (void *)pl, "exec read");
852 ERROR("exec plugin: plugin_thread_create failed.");
854 pthread_attr_destroy(&attr);
858 } /* int exec_read }}} */
860 static int exec_notification(const notification_t *n, /* {{{ */
861 user_data_t __attribute__((unused)) * user_data) {
862 program_list_and_notification_t *pln;
864 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next) {
868 /* Only execute `notification' style executables here. */
869 if ((pl->flags & PL_NOTIF_ACTION) == 0)
872 /* Skip if a child is already running. */
876 pln = malloc(sizeof(*pln));
878 ERROR("exec plugin: malloc failed.");
883 memcpy(&pln->n, n, sizeof(notification_t));
885 /* Set the `meta' member to NULL, otherwise `plugin_notification_meta_copy'
886 * will run into an endless loop. */
888 plugin_notification_meta_copy(&pln->n, n);
890 pthread_attr_init(&attr);
891 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
892 int status = plugin_thread_create(&t, &attr, exec_notification_one,
893 (void *)pln, "exec notify");
895 ERROR("exec plugin: plugin_thread_create failed.");
897 pthread_attr_destroy(&attr);
901 } /* }}} int exec_notification */
903 static int exec_shutdown(void) /* {{{ */
906 program_list_t *next;
913 kill(pl->pid, SIGTERM);
914 INFO("exec plugin: Sent SIGTERM to %hu", (unsigned short int)pl->pid);
925 } /* int exec_shutdown }}} */
927 void module_register(void) {
928 plugin_register_complex_config("exec", exec_config);
929 plugin_register_init("exec", exec_init);
930 plugin_register_read("exec", exec_read);
931 plugin_register_notification("exec", exec_notification,
932 /* user_data = */ NULL);
933 plugin_register_shutdown("exec", exec_shutdown);
934 } /* void module_register */