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) /* {{{ */
277 if ((gid != egid) && (egid != -1)) {
282 setgroups(glist_len, glist);
284 #endif /* HAVE_SETGROUPS */
286 status = setgid(gid);
288 ERROR("exec plugin: setgid (%i) failed: %s", gid, STRERRNO);
293 status = setegid(egid);
295 ERROR("exec plugin: setegid (%i) failed: %s", egid, STRERRNO);
300 status = setuid(uid);
302 ERROR("exec plugin: setuid (%i) failed: %s", uid, STRERRNO);
306 execvp(pl->exec, pl->argv);
308 ERROR("exec plugin: Failed to execute ``%s'': %s", pl->exec, STRERRNO);
310 } /* void exec_child }}} */
312 static void reset_signal_mask(void) /* {{{ */
317 sigprocmask(SIG_SETMASK, &ss, /* old mask = */ NULL);
318 } /* }}} void reset_signal_mask */
320 static int create_pipe(int fd_pipe[2]) /* {{{ */
324 status = pipe(fd_pipe);
326 ERROR("exec plugin: pipe failed: %s", STRERRNO);
331 } /* }}} int create_pipe */
333 static void close_pipe(int fd_pipe[2]) /* {{{ */
335 if (fd_pipe[0] != -1)
338 if (fd_pipe[1] != -1)
340 } /* }}} void close_pipe */
343 * Creates three pipes (one for reading, one for writing and one for errors),
344 * forks a child, sets up the pipes so that fd_in is connected to STDIN of
345 * the child and fd_out is connected to STDOUT and fd_err is connected to STDERR
346 * of the child. Then is calls `exec_child'.
348 static int fork_child(program_list_t *pl, int *fd_in, int *fd_out,
349 int *fd_err) /* {{{ */
351 int fd_pipe_in[2] = {-1, -1};
352 int fd_pipe_out[2] = {-1, -1};
353 int fd_pipe_err[2] = {-1, -1};
362 struct passwd *sp_ptr;
368 long int nambuf_size = sysconf(_SC_GETPW_R_SIZE_MAX);
369 if (nambuf_size <= 0)
370 nambuf_size = sysconf(_SC_PAGESIZE);
371 if (nambuf_size <= 0)
373 char nambuf[nambuf_size];
375 if ((create_pipe(fd_pipe_in) == -1) || (create_pipe(fd_pipe_out) == -1) ||
376 (create_pipe(fd_pipe_err) == -1))
380 status = getpwnam_r(pl->user, &sp, nambuf, sizeof(nambuf), &sp_ptr);
382 ERROR("exec plugin: Failed to get user information for user ``%s'': %s",
383 pl->user, sstrerror(status, errbuf, sizeof(errbuf)));
387 if (sp_ptr == NULL) {
388 ERROR("exec plugin: No such user: `%s'", pl->user);
395 ERROR("exec plugin: Cowardly refusing to exec program as root.");
399 /* The group configured in the configfile is set as effective group, because
400 * this way the forked process can (re-)gain the user's primary group. */
402 if (pl->group != NULL) {
403 if (*pl->group != '\0') {
404 struct group *gr_ptr = NULL;
407 long int grbuf_size = sysconf(_SC_GETGR_R_SIZE_MAX);
409 grbuf_size = sysconf(_SC_PAGESIZE);
412 char grbuf[grbuf_size];
414 status = getgrnam_r(pl->group, &gr, grbuf, sizeof(grbuf), &gr_ptr);
416 ERROR("exec plugin: Failed to get group information "
417 "for group ``%s'': %s",
418 pl->group, sstrerror(status, errbuf, sizeof(errbuf)));
421 if (gr_ptr == NULL) {
422 ERROR("exec plugin: No such group: `%s'", pl->group);
430 } /* if (pl->group == NULL) */
434 ERROR("exec plugin: fork failed: %s", STRERRNO);
436 } else if (pid == 0) {
439 /* Close all file descriptors but the pipe end we need. */
440 fd_num = getdtablesize();
441 for (int fd = 0; fd < fd_num; fd++) {
442 if ((fd == fd_pipe_in[0]) || (fd == fd_pipe_out[1]) ||
443 (fd == fd_pipe_err[1]))
448 /* Connect the `in' pipe to STDIN */
449 if (fd_pipe_in[0] != STDIN_FILENO) {
450 dup2(fd_pipe_in[0], STDIN_FILENO);
451 close(fd_pipe_in[0]);
454 /* Now connect the `out' pipe to STDOUT */
455 if (fd_pipe_out[1] != STDOUT_FILENO) {
456 dup2(fd_pipe_out[1], STDOUT_FILENO);
457 close(fd_pipe_out[1]);
460 /* Now connect the `err' pipe to STDERR */
461 if (fd_pipe_err[1] != STDERR_FILENO) {
462 dup2(fd_pipe_err[1], STDERR_FILENO);
463 close(fd_pipe_err[1]);
468 /* Unblock all signals */
471 exec_child(pl, uid, gid, egid);
472 /* does not return */
475 close(fd_pipe_in[0]);
476 close(fd_pipe_out[1]);
477 close(fd_pipe_err[1]);
480 *fd_in = fd_pipe_in[1];
482 close(fd_pipe_in[1]);
485 *fd_out = fd_pipe_out[0];
487 close(fd_pipe_out[0]);
490 *fd_err = fd_pipe_err[0];
492 close(fd_pipe_err[0]);
497 close_pipe(fd_pipe_in);
498 close_pipe(fd_pipe_out);
499 close_pipe(fd_pipe_err);
502 } /* int fork_child }}} */
504 static int parse_line(char *buffer) /* {{{ */
506 if (strncasecmp("PUTVAL", buffer, strlen("PUTVAL")) == 0)
507 return cmd_handle_putval(stdout, buffer);
508 else if (strncasecmp("PUTNOTIF", buffer, strlen("PUTNOTIF")) == 0)
509 return handle_putnotif(stdout, buffer);
511 ERROR("exec plugin: Unable to parse command, ignoring line: \"%s\"",
515 } /* int parse_line }}} */
517 static void *exec_read_one(void *arg) /* {{{ */
519 program_list_t *pl = (program_list_t *)arg;
520 int fd, fd_err, highest_fd;
523 char buffer[1200]; /* if not completely read */
524 char buffer_err[1024];
525 char *pbuffer = buffer;
526 char *pbuffer_err = buffer_err;
528 status = fork_child(pl, NULL, &fd, &fd_err);
530 /* Reset the "running" flag */
531 pthread_mutex_lock(&pl_lock);
532 pl->flags &= ~PL_RUNNING;
533 pthread_mutex_unlock(&pl_lock);
534 pthread_exit((void *)1);
538 assert(pl->pid != 0);
542 FD_SET(fd_err, &fdset);
544 /* Determine the highest file descriptor */
545 highest_fd = (fd > fd_err) ? fd : fd_err;
547 /* We use a copy of fdset, as select modifies it */
553 status = select(highest_fd + 1, ©, NULL, NULL, NULL);
560 if (FD_ISSET(fd, ©)) {
563 len = read(fd, pbuffer, sizeof(buffer) - 1 - (pbuffer - buffer));
566 if (errno == EAGAIN || errno == EINTR)
570 break; /* We've reached EOF */
574 len += pbuffer - buffer;
577 while ((pnl = strchr(pbuffer, '\n'))) {
579 if (*(pnl - 1) == '\r')
586 /* not completely read ? */
587 if (pbuffer - buffer < len) {
588 len -= pbuffer - buffer;
589 memmove(buffer, pbuffer, len);
590 pbuffer = buffer + len;
593 } else if (FD_ISSET(fd_err, ©)) {
596 len = read(fd_err, pbuffer_err,
597 sizeof(buffer_err) - 1 - (pbuffer_err - buffer_err));
600 if (errno == EAGAIN || errno == EINTR)
603 } else if (len == 0) {
604 /* We've reached EOF */
605 NOTICE("exec plugin: Program `%s' has closed STDERR.", pl->exec);
607 /* Remove file descriptor form select() set. */
608 FD_CLR(fd_err, &fdset);
612 /* Clean up file descriptor */
618 pbuffer_err[len] = '\0';
620 len += pbuffer_err - buffer_err;
621 pbuffer_err = buffer_err;
623 while ((pnl = strchr(pbuffer_err, '\n'))) {
625 if (*(pnl - 1) == '\r')
628 ERROR("exec plugin: exec_read_one: error = %s", pbuffer_err);
632 /* not completely read ? */
633 if (pbuffer_err - buffer_err < len) {
634 len -= pbuffer_err - buffer_err;
635 memmove(buffer_err, pbuffer_err, len);
636 pbuffer_err = buffer_err + len;
638 pbuffer_err = buffer_err;
644 DEBUG("exec plugin: exec_read_one: Waiting for `%s' to exit.", pl->exec);
645 if (waitpid(pl->pid, &status, 0) > 0)
648 DEBUG("exec plugin: Child %i exited with status %i.", (int)pl->pid,
653 pthread_mutex_lock(&pl_lock);
654 pl->flags &= ~PL_RUNNING;
655 pthread_mutex_unlock(&pl_lock);
661 pthread_exit((void *)0);
663 } /* void *exec_read_one }}} */
665 static void *exec_notification_one(void *arg) /* {{{ */
667 program_list_t *pl = ((program_list_and_notification_t *)arg)->pl;
668 notification_t *n = &((program_list_and_notification_t *)arg)->n;
673 const char *severity;
675 pid = fork_child(pl, &fd, NULL, NULL);
678 pthread_exit((void *)1);
681 fh = fdopen(fd, "w");
683 ERROR("exec plugin: fdopen (%i) failed: %s", fd, STRERRNO);
687 pthread_exit((void *)1);
690 severity = "FAILURE";
691 if (n->severity == NOTIF_WARNING)
692 severity = "WARNING";
693 else if (n->severity == NOTIF_OKAY)
696 fprintf(fh, "Severity: %s\n"
698 severity, CDTIME_T_TO_DOUBLE(n->time));
700 /* Print the optional fields */
701 if (strlen(n->host) > 0)
702 fprintf(fh, "Host: %s\n", n->host);
703 if (strlen(n->plugin) > 0)
704 fprintf(fh, "Plugin: %s\n", n->plugin);
705 if (strlen(n->plugin_instance) > 0)
706 fprintf(fh, "PluginInstance: %s\n", n->plugin_instance);
707 if (strlen(n->type) > 0)
708 fprintf(fh, "Type: %s\n", n->type);
709 if (strlen(n->type_instance) > 0)
710 fprintf(fh, "TypeInstance: %s\n", n->type_instance);
712 for (notification_meta_t *meta = n->meta; meta != NULL; meta = meta->next) {
713 if (meta->type == NM_TYPE_STRING)
714 fprintf(fh, "%s: %s\n", meta->name, meta->nm_value.nm_string);
715 else if (meta->type == NM_TYPE_SIGNED_INT)
716 fprintf(fh, "%s: %" PRIi64 "\n", meta->name,
717 meta->nm_value.nm_signed_int);
718 else if (meta->type == NM_TYPE_UNSIGNED_INT)
719 fprintf(fh, "%s: %" PRIu64 "\n", meta->name,
720 meta->nm_value.nm_unsigned_int);
721 else if (meta->type == NM_TYPE_DOUBLE)
722 fprintf(fh, "%s: %e\n", meta->name, meta->nm_value.nm_double);
723 else if (meta->type == NM_TYPE_BOOLEAN)
724 fprintf(fh, "%s: %s\n", meta->name,
725 meta->nm_value.nm_boolean ? "true" : "false");
728 fprintf(fh, "\n%s\n", n->message);
733 waitpid(pid, &status, 0);
735 DEBUG("exec plugin: Child %i exited with status %i.", pid, status);
738 plugin_notification_meta_free(n->meta);
741 pthread_exit((void *)0);
743 } /* void *exec_notification_one }}} */
745 static int exec_init(void) /* {{{ */
747 struct sigaction sa = {.sa_handler = sigchld_handler};
749 sigaction(SIGCHLD, &sa, NULL);
751 #if defined(HAVE_SYS_CAPABILITY_H) && defined(CAP_SETUID) && defined(CAP_SETGID)
752 if ((check_capability(CAP_SETUID) != 0) ||
753 (check_capability(CAP_SETGID) != 0)) {
756 "exec plugin: Running collectd as root, but the CAP_SETUID "
757 "or CAP_SETGID capabilities are missing. The plugin's read function "
758 "will probably fail. Is your init system dropping capabilities?");
761 "exec plugin: collectd doesn't have the CAP_SETUID or "
762 "CAP_SETGID capabilities. If you don't want to run collectd as root, "
763 "try running \"setcap 'cap_setuid=ep cap_setgid=ep'\" on the "
769 } /* int exec_init }}} */
771 static int exec_read(void) /* {{{ */
773 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next) {
777 /* Only execute `normal' style executables here. */
778 if ((pl->flags & PL_NORMAL) == 0)
781 pthread_mutex_lock(&pl_lock);
782 /* Skip if a child is already running. */
783 if ((pl->flags & PL_RUNNING) != 0) {
784 pthread_mutex_unlock(&pl_lock);
787 pl->flags |= PL_RUNNING;
788 pthread_mutex_unlock(&pl_lock);
790 pthread_attr_init(&attr);
791 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
792 plugin_thread_create(&t, &attr, exec_read_one, (void *)pl, "exec read");
793 pthread_attr_destroy(&attr);
797 } /* int exec_read }}} */
799 static int exec_notification(const notification_t *n, /* {{{ */
800 user_data_t __attribute__((unused)) * user_data) {
801 program_list_and_notification_t *pln;
803 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next) {
807 /* Only execute `notification' style executables here. */
808 if ((pl->flags & PL_NOTIF_ACTION) == 0)
811 /* Skip if a child is already running. */
815 pln = malloc(sizeof(*pln));
817 ERROR("exec plugin: malloc failed.");
822 memcpy(&pln->n, n, sizeof(notification_t));
824 /* Set the `meta' member to NULL, otherwise `plugin_notification_meta_copy'
825 * will run into an endless loop. */
827 plugin_notification_meta_copy(&pln->n, n);
829 pthread_attr_init(&attr);
830 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
831 plugin_thread_create(&t, &attr, exec_notification_one, (void *)pln,
833 pthread_attr_destroy(&attr);
837 } /* }}} int exec_notification */
839 static int exec_shutdown(void) /* {{{ */
842 program_list_t *next;
849 kill(pl->pid, SIGTERM);
850 INFO("exec plugin: Sent SIGTERM to %hu", (unsigned short int)pl->pid);
861 } /* int exec_shutdown }}} */
863 void module_register(void) {
864 plugin_register_complex_config("exec", exec_config);
865 plugin_register_init("exec", exec_init);
866 plugin_register_read("exec", exec_read);
867 plugin_register_notification("exec", exec_notification,
868 /* user_data = */ NULL);
869 plugin_register_shutdown("exec", exec_shutdown);
870 } /* void module_register */