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 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) /* {{{ */
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,
295 sstrerror(errno, errbuf, sizeof(errbuf)));
300 status = setegid(egid);
302 ERROR("exec plugin: setegid (%i) failed: %s", egid,
303 sstrerror(errno, errbuf, sizeof(errbuf)));
308 status = setuid(uid);
310 ERROR("exec plugin: setuid (%i) failed: %s", uid,
311 sstrerror(errno, errbuf, sizeof(errbuf)));
315 execvp(pl->exec, pl->argv);
317 ERROR("exec plugin: Failed to execute ``%s'': %s", pl->exec,
318 sstrerror(errno, errbuf, sizeof(errbuf)));
320 } /* void exec_child }}} */
322 static void reset_signal_mask(void) /* {{{ */
327 sigprocmask(SIG_SETMASK, &ss, /* old mask = */ NULL);
328 } /* }}} void reset_signal_mask */
330 static int create_pipe(int fd_pipe[2]) /* {{{ */
335 status = pipe(fd_pipe);
337 ERROR("exec plugin: pipe failed: %s",
338 sstrerror(errno, errbuf, sizeof(errbuf)));
343 } /* }}} int create_pipe */
345 static void close_pipe(int fd_pipe[2]) /* {{{ */
347 if (fd_pipe[0] != -1)
350 if (fd_pipe[1] != -1)
352 } /* }}} void close_pipe */
355 * Get effective group ID from group name.
357 * pl :program list struct with group name
358 * gid :group id to fallback in case egid cannot be determined.
360 * egid effective group id if successfull,
361 * -1 if group is not defined/not found.
362 * -2 for any buffer allocation error.
364 static int getegr_id(program_list_t *pl, int gid) /* {{{ */
366 if (pl->group == NULL) {
369 if (strcmp(pl->group, "") == 0) {
372 struct group *gr_ptr = NULL;
375 long int grbuf_size = sysconf(_SC_GETGR_R_SIZE_MAX);
377 grbuf_size = sysconf(_SC_PAGESIZE);
385 temp = realloc(grbuf, grbuf_size);
387 ERROR("exec plugin: getegr_id for %s: realloc buffer[%ld] failed ",
388 pl->group, grbuf_size);
393 if (getgrnam_r(pl->group, &gr, grbuf, grbuf_size, &gr_ptr) == 0) {
395 if (gr_ptr == NULL) {
396 ERROR("exec plugin: No such group: `%s'", pl->group);
400 } else if (errno == ERANGE) {
401 grbuf_size += grbuf_size; // increment buffer size and try again
404 ERROR("exec plugin: getegr_id failed %s",
405 sstrerror(errno, errbuf, sizeof(errbuf)));
409 } while (grbuf_size <= MAX_GRBUF_SIZE);
410 ERROR("exec plugin: getegr_id Max grbuf size reached for %s", pl->group);
416 * Creates three pipes (one for reading, one for writing and one for errors),
417 * forks a child, sets up the pipes so that fd_in is connected to STDIN of
418 * the child and fd_out is connected to STDOUT and fd_err is connected to STDERR
419 * of the child. Then is calls `exec_child'.
421 static int fork_child(program_list_t *pl, int *fd_in, int *fd_out,
422 int *fd_err) /* {{{ */
424 int fd_pipe_in[2] = {-1, -1};
425 int fd_pipe_out[2] = {-1, -1};
426 int fd_pipe_err[2] = {-1, -1};
435 struct passwd *sp_ptr;
441 long int nambuf_size = sysconf(_SC_GETPW_R_SIZE_MAX);
442 if (nambuf_size <= 0)
443 nambuf_size = sysconf(_SC_PAGESIZE);
444 if (nambuf_size <= 0)
446 char nambuf[nambuf_size];
448 if ((create_pipe(fd_pipe_in) == -1) || (create_pipe(fd_pipe_out) == -1) ||
449 (create_pipe(fd_pipe_err) == -1))
453 status = getpwnam_r(pl->user, &sp, nambuf, sizeof(nambuf), &sp_ptr);
455 ERROR("exec plugin: Failed to get user information for user ``%s'': %s",
456 pl->user, sstrerror(status, errbuf, sizeof(errbuf)));
460 if (sp_ptr == NULL) {
461 ERROR("exec plugin: No such user: `%s'", pl->user);
468 ERROR("exec plugin: Cowardly refusing to exec program as root.");
472 egid = getegr_id(pl, gid);
479 ERROR("exec plugin: fork failed: %s",
480 sstrerror(errno, errbuf, sizeof(errbuf)));
482 } else if (pid == 0) {
485 /* Close all file descriptors but the pipe end we need. */
486 fd_num = getdtablesize();
487 for (int fd = 0; fd < fd_num; fd++) {
488 if ((fd == fd_pipe_in[0]) || (fd == fd_pipe_out[1]) ||
489 (fd == fd_pipe_err[1]))
494 /* Connect the `in' pipe to STDIN */
495 if (fd_pipe_in[0] != STDIN_FILENO) {
496 dup2(fd_pipe_in[0], STDIN_FILENO);
497 close(fd_pipe_in[0]);
500 /* Now connect the `out' pipe to STDOUT */
501 if (fd_pipe_out[1] != STDOUT_FILENO) {
502 dup2(fd_pipe_out[1], STDOUT_FILENO);
503 close(fd_pipe_out[1]);
506 /* Now connect the `err' pipe to STDERR */
507 if (fd_pipe_err[1] != STDERR_FILENO) {
508 dup2(fd_pipe_err[1], STDERR_FILENO);
509 close(fd_pipe_err[1]);
514 /* Unblock all signals */
517 exec_child(pl, uid, gid, egid);
518 /* does not return */
521 close(fd_pipe_in[0]);
522 close(fd_pipe_out[1]);
523 close(fd_pipe_err[1]);
526 *fd_in = fd_pipe_in[1];
528 close(fd_pipe_in[1]);
531 *fd_out = fd_pipe_out[0];
533 close(fd_pipe_out[0]);
536 *fd_err = fd_pipe_err[0];
538 close(fd_pipe_err[0]);
543 close_pipe(fd_pipe_in);
544 close_pipe(fd_pipe_out);
545 close_pipe(fd_pipe_err);
548 } /* int fork_child }}} */
550 static int parse_line(char *buffer) /* {{{ */
552 if (strncasecmp("PUTVAL", buffer, strlen("PUTVAL")) == 0)
553 return cmd_handle_putval(stdout, buffer);
554 else if (strncasecmp("PUTNOTIF", buffer, strlen("PUTNOTIF")) == 0)
555 return handle_putnotif(stdout, buffer);
557 ERROR("exec plugin: Unable to parse command, ignoring line: \"%s\"",
561 } /* int parse_line }}} */
563 static void *exec_read_one(void *arg) /* {{{ */
565 program_list_t *pl = (program_list_t *)arg;
566 int fd, fd_err, highest_fd;
569 char buffer[1200]; /* if not completely read */
570 char buffer_err[1024];
571 char *pbuffer = buffer;
572 char *pbuffer_err = buffer_err;
574 status = fork_child(pl, NULL, &fd, &fd_err);
576 /* Reset the "running" flag */
577 pthread_mutex_lock(&pl_lock);
578 pl->flags &= ~PL_RUNNING;
579 pthread_mutex_unlock(&pl_lock);
580 pthread_exit((void *)1);
584 assert(pl->pid != 0);
588 FD_SET(fd_err, &fdset);
590 /* Determine the highest file descriptor */
591 highest_fd = (fd > fd_err) ? fd : fd_err;
593 /* We use a copy of fdset, as select modifies it */
599 status = select(highest_fd + 1, ©, NULL, NULL, NULL);
606 if (FD_ISSET(fd, ©)) {
609 len = read(fd, pbuffer, sizeof(buffer) - 1 - (pbuffer - buffer));
612 if (errno == EAGAIN || errno == EINTR)
616 break; /* We've reached EOF */
620 len += pbuffer - buffer;
623 while ((pnl = strchr(pbuffer, '\n'))) {
625 if (*(pnl - 1) == '\r')
632 /* not completely read ? */
633 if (pbuffer - buffer < len) {
634 len -= pbuffer - buffer;
635 memmove(buffer, pbuffer, len);
636 pbuffer = buffer + len;
639 } else if (FD_ISSET(fd_err, ©)) {
642 len = read(fd_err, pbuffer_err,
643 sizeof(buffer_err) - 1 - (pbuffer_err - buffer_err));
646 if (errno == EAGAIN || errno == EINTR)
649 } else if (len == 0) {
650 /* We've reached EOF */
651 NOTICE("exec plugin: Program `%s' has closed STDERR.", pl->exec);
653 /* Remove file descriptor form select() set. */
654 FD_CLR(fd_err, &fdset);
658 /* Clean up file descriptor */
664 pbuffer_err[len] = '\0';
666 len += pbuffer_err - buffer_err;
667 pbuffer_err = buffer_err;
669 while ((pnl = strchr(pbuffer_err, '\n'))) {
671 if (*(pnl - 1) == '\r')
674 ERROR("exec plugin: exec_read_one: error = %s", pbuffer_err);
678 /* not completely read ? */
679 if (pbuffer_err - buffer_err < len) {
680 len -= pbuffer_err - buffer_err;
681 memmove(buffer_err, pbuffer_err, len);
682 pbuffer_err = buffer_err + len;
684 pbuffer_err = buffer_err;
690 DEBUG("exec plugin: exec_read_one: Waiting for `%s' to exit.", pl->exec);
691 if (waitpid(pl->pid, &status, 0) > 0)
694 DEBUG("exec plugin: Child %i exited with status %i.", (int)pl->pid,
699 pthread_mutex_lock(&pl_lock);
700 pl->flags &= ~PL_RUNNING;
701 pthread_mutex_unlock(&pl_lock);
707 pthread_exit((void *)0);
709 } /* void *exec_read_one }}} */
711 static void *exec_notification_one(void *arg) /* {{{ */
713 program_list_t *pl = ((program_list_and_notification_t *)arg)->pl;
714 notification_t *n = &((program_list_and_notification_t *)arg)->n;
719 const char *severity;
721 pid = fork_child(pl, &fd, NULL, NULL);
724 pthread_exit((void *)1);
727 fh = fdopen(fd, "w");
730 ERROR("exec plugin: fdopen (%i) failed: %s", fd,
731 sstrerror(errno, errbuf, sizeof(errbuf)));
735 pthread_exit((void *)1);
738 severity = "FAILURE";
739 if (n->severity == NOTIF_WARNING)
740 severity = "WARNING";
741 else if (n->severity == NOTIF_OKAY)
744 fprintf(fh, "Severity: %s\n"
746 severity, CDTIME_T_TO_DOUBLE(n->time));
748 /* Print the optional fields */
749 if (strlen(n->host) > 0)
750 fprintf(fh, "Host: %s\n", n->host);
751 if (strlen(n->plugin) > 0)
752 fprintf(fh, "Plugin: %s\n", n->plugin);
753 if (strlen(n->plugin_instance) > 0)
754 fprintf(fh, "PluginInstance: %s\n", n->plugin_instance);
755 if (strlen(n->type) > 0)
756 fprintf(fh, "Type: %s\n", n->type);
757 if (strlen(n->type_instance) > 0)
758 fprintf(fh, "TypeInstance: %s\n", n->type_instance);
760 for (notification_meta_t *meta = n->meta; meta != NULL; meta = meta->next) {
761 if (meta->type == NM_TYPE_STRING)
762 fprintf(fh, "%s: %s\n", meta->name, meta->nm_value.nm_string);
763 else if (meta->type == NM_TYPE_SIGNED_INT)
764 fprintf(fh, "%s: %" PRIi64 "\n", meta->name,
765 meta->nm_value.nm_signed_int);
766 else if (meta->type == NM_TYPE_UNSIGNED_INT)
767 fprintf(fh, "%s: %" PRIu64 "\n", meta->name,
768 meta->nm_value.nm_unsigned_int);
769 else if (meta->type == NM_TYPE_DOUBLE)
770 fprintf(fh, "%s: %e\n", meta->name, meta->nm_value.nm_double);
771 else if (meta->type == NM_TYPE_BOOLEAN)
772 fprintf(fh, "%s: %s\n", meta->name,
773 meta->nm_value.nm_boolean ? "true" : "false");
776 fprintf(fh, "\n%s\n", n->message);
781 waitpid(pid, &status, 0);
783 DEBUG("exec plugin: Child %i exited with status %i.", pid, status);
786 plugin_notification_meta_free(n->meta);
789 pthread_exit((void *)0);
791 } /* void *exec_notification_one }}} */
793 static int exec_init(void) /* {{{ */
795 struct sigaction sa = {.sa_handler = sigchld_handler};
797 sigaction(SIGCHLD, &sa, NULL);
799 #if defined(HAVE_SYS_CAPABILITY_H) && defined(CAP_SETUID) && defined(CAP_SETGID)
800 if ((check_capability(CAP_SETUID) != 0) ||
801 (check_capability(CAP_SETGID) != 0)) {
804 "exec plugin: Running collectd as root, but the CAP_SETUID "
805 "or CAP_SETGID capabilities are missing. The plugin's read function "
806 "will probably fail. Is your init system dropping capabilities?");
809 "exec plugin: collectd doesn't have the CAP_SETUID or "
810 "CAP_SETGID capabilities. If you don't want to run collectd as root, "
811 "try running \"setcap 'cap_setuid=ep cap_setgid=ep'\" on the "
817 } /* int exec_init }}} */
819 static int exec_read(void) /* {{{ */
821 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next) {
825 /* Only execute `normal' style executables here. */
826 if ((pl->flags & PL_NORMAL) == 0)
829 pthread_mutex_lock(&pl_lock);
830 /* Skip if a child is already running. */
831 if ((pl->flags & PL_RUNNING) != 0) {
832 pthread_mutex_unlock(&pl_lock);
835 pl->flags |= PL_RUNNING;
836 pthread_mutex_unlock(&pl_lock);
838 pthread_attr_init(&attr);
839 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
841 plugin_thread_create(&t, &attr, exec_read_one, (void *)pl, "exec read");
843 ERROR("exec plugin: plugin_thread_create failed.");
845 pthread_attr_destroy(&attr);
849 } /* int exec_read }}} */
851 static int exec_notification(const notification_t *n, /* {{{ */
852 user_data_t __attribute__((unused)) * user_data) {
853 program_list_and_notification_t *pln;
855 for (program_list_t *pl = pl_head; pl != NULL; pl = pl->next) {
859 /* Only execute `notification' style executables here. */
860 if ((pl->flags & PL_NOTIF_ACTION) == 0)
863 /* Skip if a child is already running. */
867 pln = malloc(sizeof(*pln));
869 ERROR("exec plugin: malloc failed.");
874 memcpy(&pln->n, n, sizeof(notification_t));
876 /* Set the `meta' member to NULL, otherwise `plugin_notification_meta_copy'
877 * will run into an endless loop. */
879 plugin_notification_meta_copy(&pln->n, n);
881 pthread_attr_init(&attr);
882 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
883 int status = plugin_thread_create(&t, &attr, exec_notification_one,
884 (void *)pln, "exec notify");
886 ERROR("exec plugin: plugin_thread_create failed.");
888 pthread_attr_destroy(&attr);
892 } /* }}} int exec_notification */
894 static int exec_shutdown(void) /* {{{ */
897 program_list_t *next;
904 kill(pl->pid, SIGTERM);
905 INFO("exec plugin: Sent SIGTERM to %hu", (unsigned short int)pl->pid);
916 } /* int exec_shutdown }}} */
918 void module_register(void) {
919 plugin_register_complex_config("exec", exec_config);
920 plugin_register_init("exec", exec_init);
921 plugin_register_read("exec", exec_read);
922 plugin_register_notification("exec", exec_notification,
923 /* user_data = */ NULL);
924 plugin_register_shutdown("exec", exec_shutdown);
925 } /* void module_register */