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 static void unset_environment(void) /* {{{ */
279 unsetenv("COLLECTD_INTERVAL");
280 unsetenv("COLLECTD_HOSTNAME");
282 snprintf(env_interval, sizeof(env_interval), "COLLECTD_INTERVAL");
283 putenv(env_interval);
284 snprintf(env_hostname, sizeof(env_hostname), "COLLECTD_HOSTNAME");
285 putenv(env_hostname);
287 } /* }}} void unset_environment */
289 __attribute__((noreturn)) static void exec_child(program_list_t *pl, int uid,
290 int gid, int egid) /* {{{ */
303 if ((gid != egid) && (egid != -1)) {
308 setgroups(glist_len, glist);
310 #endif /* HAVE_SETGROUPS */
312 status = setgid(gid);
314 ERROR("exec plugin: setgid (%i) failed: %s", gid,
315 sstrerror(errno, errbuf, sizeof(errbuf)));
320 status = setegid(egid);
322 ERROR("exec plugin: setegid (%i) failed: %s", egid,
323 sstrerror(errno, errbuf, sizeof(errbuf)));
328 status = setuid(uid);
330 ERROR("exec plugin: setuid (%i) failed: %s", uid,
331 sstrerror(errno, errbuf, sizeof(errbuf)));
335 execvp(pl->exec, pl->argv);
337 ERROR("exec plugin: Failed to execute ``%s'': %s", pl->exec,
338 sstrerror(errno, errbuf, sizeof(errbuf)));
340 } /* void exec_child }}} */
342 static void reset_signal_mask(void) /* {{{ */
347 sigprocmask(SIG_SETMASK, &ss, /* old mask = */ NULL);
348 } /* }}} void reset_signal_mask */
350 static int create_pipe(int fd_pipe[2]) /* {{{ */
355 status = pipe(fd_pipe);
357 ERROR("exec plugin: pipe failed: %s",
358 sstrerror(errno, errbuf, sizeof(errbuf)));
363 } /* }}} int create_pipe */
365 static void close_pipe(int fd_pipe[2]) /* {{{ */
367 if (fd_pipe[0] != -1)
370 if (fd_pipe[1] != -1)
372 } /* }}} void close_pipe */
375 * Get effective group ID from group name.
377 * pl :program list struct with group name
378 * gid :group id to fallback in case egid cannot be determined.
380 * egid effective group id if successfull,
381 * -1 if group is not defined/not found.
382 * -2 for any buffer allocation error.
384 static int getegr_id(program_list_t *pl, int gid) /* {{{ */
386 if (pl->group == NULL) {
389 if (strcmp(pl->group, "") == 0) {
392 struct group *gr_ptr = NULL;
395 long int grbuf_size = sysconf(_SC_GETGR_R_SIZE_MAX);
397 grbuf_size = sysconf(_SC_PAGESIZE);
405 temp = realloc(grbuf, grbuf_size);
407 ERROR("exec plugin: getegr_id for %s: realloc buffer[%ld] failed ",
408 pl->group, grbuf_size);
413 if (getgrnam_r(pl->group, &gr, grbuf, grbuf_size, &gr_ptr) == 0) {
415 if (gr_ptr == NULL) {
416 ERROR("exec plugin: No such group: `%s'", pl->group);
420 } else if (errno == ERANGE) {
421 grbuf_size += grbuf_size; // increment buffer size and try again
424 ERROR("exec plugin: getegr_id failed %s",
425 sstrerror(errno, errbuf, sizeof(errbuf)));
429 } while (grbuf_size <= MAX_GRBUF_SIZE);
430 ERROR("exec plugin: getegr_id Max grbuf size reached for %s", pl->group);
436 * Creates three pipes (one for reading, one for writing and one for errors),
437 * forks a child, sets up the pipes so that fd_in is connected to STDIN of
438 * the child and fd_out is connected to STDOUT and fd_err is connected to STDERR
439 * of the child. Then is calls `exec_child'.
441 static int fork_child(program_list_t *pl, int *fd_in, int *fd_out,
442 int *fd_err) /* {{{ */
444 int fd_pipe_in[2] = {-1, -1};
445 int fd_pipe_out[2] = {-1, -1};
446 int fd_pipe_err[2] = {-1, -1};
455 struct passwd *sp_ptr;
461 long int nambuf_size = sysconf(_SC_GETPW_R_SIZE_MAX);
462 if (nambuf_size <= 0)
463 nambuf_size = sysconf(_SC_PAGESIZE);
464 if (nambuf_size <= 0)
466 char nambuf[nambuf_size];
468 if ((create_pipe(fd_pipe_in) == -1) || (create_pipe(fd_pipe_out) == -1) ||
469 (create_pipe(fd_pipe_err) == -1))
473 status = getpwnam_r(pl->user, &sp, nambuf, sizeof(nambuf), &sp_ptr);
475 ERROR("exec plugin: Failed to get user information for user ``%s'': %s",
476 pl->user, sstrerror(status, errbuf, sizeof(errbuf)));
480 if (sp_ptr == NULL) {
481 ERROR("exec plugin: No such user: `%s'", pl->user);
488 ERROR("exec plugin: Cowardly refusing to exec program as root.");
492 egid = getegr_id(pl, gid);
501 ERROR("exec plugin: fork failed: %s",
502 sstrerror(errno, errbuf, sizeof(errbuf)));
504 } else if (pid == 0) {
507 /* Close all file descriptors but the pipe end we need. */
508 fd_num = getdtablesize();
509 for (int fd = 0; fd < fd_num; fd++) {
510 if ((fd == fd_pipe_in[0]) || (fd == fd_pipe_out[1]) ||
511 (fd == fd_pipe_err[1]))
516 /* Connect the `in' pipe to STDIN */
517 if (fd_pipe_in[0] != STDIN_FILENO) {
518 dup2(fd_pipe_in[0], STDIN_FILENO);
519 close(fd_pipe_in[0]);
522 /* Now connect the `out' pipe to STDOUT */
523 if (fd_pipe_out[1] != STDOUT_FILENO) {
524 dup2(fd_pipe_out[1], STDOUT_FILENO);
525 close(fd_pipe_out[1]);
528 /* Now connect the `err' pipe to STDERR */
529 if (fd_pipe_err[1] != STDERR_FILENO) {
530 dup2(fd_pipe_err[1], STDERR_FILENO);
531 close(fd_pipe_err[1]);
534 /* Unblock all signals */
537 exec_child(pl, uid, gid, egid);
538 /* does not return */
543 close(fd_pipe_in[0]);
544 close(fd_pipe_out[1]);
545 close(fd_pipe_err[1]);
548 *fd_in = fd_pipe_in[1];
550 close(fd_pipe_in[1]);
553 *fd_out = fd_pipe_out[0];
555 close(fd_pipe_out[0]);
558 *fd_err = fd_pipe_err[0];
560 close(fd_pipe_err[0]);
567 close_pipe(fd_pipe_in);
568 close_pipe(fd_pipe_out);
569 close_pipe(fd_pipe_err);
572 } /* int fork_child }}} */
574 static int parse_line(char *buffer) /* {{{ */
576 if (strncasecmp("PUTVAL", buffer, strlen("PUTVAL")) == 0)
577 return cmd_handle_putval(stdout, buffer);
578 else if (strncasecmp("PUTNOTIF", buffer, strlen("PUTNOTIF")) == 0)
579 return handle_putnotif(stdout, buffer);
581 ERROR("exec plugin: Unable to parse command, ignoring line: \"%s\"",
585 } /* int parse_line }}} */
587 static void *exec_read_one(void *arg) /* {{{ */
589 program_list_t *pl = (program_list_t *)arg;
590 int fd, fd_err, highest_fd;
593 char buffer[1200]; /* if not completely read */
594 char buffer_err[1024];
595 char *pbuffer = buffer;
596 char *pbuffer_err = buffer_err;
598 status = fork_child(pl, NULL, &fd, &fd_err);
600 /* Reset the "running" flag */
601 pthread_mutex_lock(&pl_lock);
602 pl->flags &= ~PL_RUNNING;
603 pthread_mutex_unlock(&pl_lock);
604 pthread_exit((void *)1);
608 assert(pl->pid != 0);
612 FD_SET(fd_err, &fdset);
614 /* Determine the highest file descriptor */
615 highest_fd = (fd > fd_err) ? fd : fd_err;
617 /* We use a copy of fdset, as select modifies it */
623 status = select(highest_fd + 1, ©, NULL, NULL, NULL);
630 if (FD_ISSET(fd, ©)) {
633 len = read(fd, pbuffer, sizeof(buffer) - 1 - (pbuffer - buffer));
636 if (errno == EAGAIN || errno == EINTR)
640 break; /* We've reached EOF */
644 len += pbuffer - buffer;
647 while ((pnl = strchr(pbuffer, '\n'))) {
649 if (*(pnl - 1) == '\r')
656 /* not completely read ? */
657 if (pbuffer - buffer < len) {
658 len -= pbuffer - buffer;
659 memmove(buffer, pbuffer, len);
660 pbuffer = buffer + len;
663 } else if (FD_ISSET(fd_err, ©)) {
666 len = read(fd_err, pbuffer_err,
667 sizeof(buffer_err) - 1 - (pbuffer_err - buffer_err));
670 if (errno == EAGAIN || errno == EINTR)
673 } else if (len == 0) {
674 /* We've reached EOF */
675 NOTICE("exec plugin: Program `%s' has closed STDERR.", pl->exec);
677 /* Remove file descriptor form select() set. */
678 FD_CLR(fd_err, &fdset);
682 /* Clean up file descriptor */
688 pbuffer_err[len] = '\0';
690 len += pbuffer_err - buffer_err;
691 pbuffer_err = buffer_err;
693 while ((pnl = strchr(pbuffer_err, '\n'))) {
695 if (*(pnl - 1) == '\r')
698 ERROR("exec plugin: exec_read_one: error = %s", pbuffer_err);
702 /* not completely read ? */
703 if (pbuffer_err - buffer_err < len) {
704 len -= pbuffer_err - buffer_err;
705 memmove(buffer_err, pbuffer_err, len);
706 pbuffer_err = buffer_err + len;
708 pbuffer_err = buffer_err;
714 DEBUG("exec plugin: exec_read_one: Waiting for `%s' to exit.", pl->exec);
715 if (waitpid(pl->pid, &status, 0) > 0)
718 DEBUG("exec plugin: Child %i exited with status %i.", (int)pl->pid,
723 pthread_mutex_lock(&pl_lock);
724 pl->flags &= ~PL_RUNNING;
725 pthread_mutex_unlock(&pl_lock);
731 pthread_exit((void *)0);
733 } /* void *exec_read_one }}} */
735 static void *exec_notification_one(void *arg) /* {{{ */
737 program_list_t *pl = ((program_list_and_notification_t *)arg)->pl;
738 notification_t *n = &((program_list_and_notification_t *)arg)->n;
743 const char *severity;
745 pid = fork_child(pl, &fd, NULL, NULL);
748 pthread_exit((void *)1);
751 fh = fdopen(fd, "w");
754 ERROR("exec plugin: fdopen (%i) failed: %s", fd,
755 sstrerror(errno, errbuf, sizeof(errbuf)));
759 pthread_exit((void *)1);
762 severity = "FAILURE";
763 if (n->severity == NOTIF_WARNING)
764 severity = "WARNING";
765 else if (n->severity == NOTIF_OKAY)
768 fprintf(fh, "Severity: %s\n"
770 severity, CDTIME_T_TO_DOUBLE(n->time));
772 /* Print the optional fields */
773 if (strlen(n->host) > 0)
774 fprintf(fh, "Host: %s\n", n->host);
775 if (strlen(n->plugin) > 0)
776 fprintf(fh, "Plugin: %s\n", n->plugin);
777 if (strlen(n->plugin_instance) > 0)
778 fprintf(fh, "PluginInstance: %s\n", n->plugin_instance);
779 if (strlen(n->type) > 0)
780 fprintf(fh, "Type: %s\n", n->type);
781 if (strlen(n->type_instance) > 0)
782 fprintf(fh, "TypeInstance: %s\n", n->type_instance);
784 for (notification_meta_t *meta = n->meta; meta != NULL; meta = meta->next) {
785 if (meta->type == NM_TYPE_STRING)
786 fprintf(fh, "%s: %s\n", meta->name, meta->nm_value.nm_string);
787 else if (meta->type == NM_TYPE_SIGNED_INT)
788 fprintf(fh, "%s: %" PRIi64 "\n", meta->name,
789 meta->nm_value.nm_signed_int);
790 else if (meta->type == NM_TYPE_UNSIGNED_INT)
791 fprintf(fh, "%s: %" PRIu64 "\n", meta->name,
792 meta->nm_value.nm_unsigned_int);
793 else if (meta->type == NM_TYPE_DOUBLE)
794 fprintf(fh, "%s: %e\n", meta->name, meta->nm_value.nm_double);
795 else if (meta->type == NM_TYPE_BOOLEAN)
796 fprintf(fh, "%s: %s\n", meta->name,
797 meta->nm_value.nm_boolean ? "true" : "false");
800 fprintf(fh, "\n%s\n", n->message);
805 waitpid(pid, &status, 0);
807 DEBUG("exec plugin: Child %i exited with status %i.", pid, status);
810 plugin_notification_meta_free(n->meta);
813 pthread_exit((void *)0);
815 } /* void *exec_notification_one }}} */
817 static int exec_init(void) /* {{{ */
819 struct sigaction sa = {.sa_handler = sigchld_handler};
821 sigaction(SIGCHLD, &sa, NULL);
823 #if defined(HAVE_SYS_CAPABILITY_H) && defined(CAP_SETUID) && defined(CAP_SETGID)
824 if ((check_capability(CAP_SETUID) != 0) ||
825 (check_capability(CAP_SETGID) != 0)) {
828 "exec plugin: Running collectd as root, but the CAP_SETUID "
829 "or CAP_SETGID capabilities are missing. The plugin's read function "
830 "will probably fail. Is your init system dropping capabilities?");
833 "exec plugin: collectd doesn't have the CAP_SETUID or "
834 "CAP_SETGID capabilities. If you don't want to run collectd as root, "
835 "try running \"setcap 'cap_setuid=ep cap_setgid=ep'\" on the "
841 } /* int exec_init }}} */
843 static int exec_read(void) /* {{{ */
845 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next) {
849 /* Only execute `normal' style executables here. */
850 if ((pl->flags & PL_NORMAL) == 0)
853 pthread_mutex_lock(&pl_lock);
854 /* Skip if a child is already running. */
855 if ((pl->flags & PL_RUNNING) != 0) {
856 pthread_mutex_unlock(&pl_lock);
859 pl->flags |= PL_RUNNING;
860 pthread_mutex_unlock(&pl_lock);
862 pthread_attr_init(&attr);
863 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
865 plugin_thread_create(&t, &attr, exec_read_one, (void *)pl, "exec read");
867 ERROR("exec plugin: plugin_thread_create failed.");
869 pthread_attr_destroy(&attr);
873 } /* int exec_read }}} */
875 static int exec_notification(const notification_t *n, /* {{{ */
876 user_data_t __attribute__((unused)) * user_data) {
877 program_list_and_notification_t *pln;
879 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next) {
883 /* Only execute `notification' style executables here. */
884 if ((pl->flags & PL_NOTIF_ACTION) == 0)
887 /* Skip if a child is already running. */
891 pln = malloc(sizeof(*pln));
893 ERROR("exec plugin: malloc failed.");
898 memcpy(&pln->n, n, sizeof(notification_t));
900 /* Set the `meta' member to NULL, otherwise `plugin_notification_meta_copy'
901 * will run into an endless loop. */
903 plugin_notification_meta_copy(&pln->n, n);
905 pthread_attr_init(&attr);
906 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
907 int status = plugin_thread_create(&t, &attr, exec_notification_one,
908 (void *)pln, "exec notify");
910 ERROR("exec plugin: plugin_thread_create failed.");
912 pthread_attr_destroy(&attr);
916 } /* }}} int exec_notification */
918 static int exec_shutdown(void) /* {{{ */
921 program_list_t *next;
928 kill(pl->pid, SIGTERM);
929 INFO("exec plugin: Sent SIGTERM to %hu", (unsigned short int)pl->pid);
940 } /* int exec_shutdown }}} */
942 void module_register(void) {
943 plugin_register_complex_config("exec", exec_config);
944 plugin_register_init("exec", exec_init);
945 plugin_register_read("exec", exec_read);
946 plugin_register_notification("exec", exec_notification,
947 /* user_data = */ NULL);
948 plugin_register_shutdown("exec", exec_shutdown);
949 } /* void module_register */