1 files changed, 447 insertions, 0 deletions

diff --git a/sys/contrib/openzfs/cmd/zed/zed_exec.c b/sys/contrib/openzfs/cmd/zed/zed_exec.c
new file mode 100644
index 000000000000..a14af4f20a85
--- /dev/null
+++ b/sys/contrib/openzfs/cmd/zed/zed_exec.c
@@ -0,0 +1,447 @@
+// SPDX-License-Identifier: CDDL-1.0
+/*
+ * This file is part of the ZFS Event Daemon (ZED).
+ *
+ * Developed at Lawrence Livermore National Laboratory (LLNL-CODE-403049).
+ * Copyright (C) 2013-2014 Lawrence Livermore National Security, LLC.
+ * Refer to the OpenZFS git commit log for authoritative copyright attribution.
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License Version 1.0 (CDDL-1.0).
+ * You can obtain a copy of the license from the top-level file
+ * "OPENSOLARIS.LICENSE" or at <http://opensource.org/licenses/CDDL-1.0>.
+ * You may not use this file except in compliance with the license.
+ */
+
+#include <assert.h>
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stddef.h>
+#include <sys/avl.h>
+#include <sys/resource.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <time.h>
+#include <unistd.h>
+#include <pthread.h>
+#include <signal.h>
+
+#include "zed_exec.h"
+#include "zed_log.h"
+#include "zed_strings.h"
+
+#define	ZEVENT_FILENO	3
+
+struct launched_process_node {
+	avl_node_t node;
+	pid_t pid;
+	uint64_t eid;
+	char *name;
+};
+
+static int
+_launched_process_node_compare(const void *x1, const void *x2)
+{
+	pid_t p1;
+	pid_t p2;
+
+	assert(x1 != NULL);
+	assert(x2 != NULL);
+
+	p1 = ((const struct launched_process_node *) x1)->pid;
+	p2 = ((const struct launched_process_node *) x2)->pid;
+
+	if (p1 < p2)
+		return (-1);
+	else if (p1 == p2)
+		return (0);
+	else
+		return (1);
+}
+
+static pthread_t _reap_children_tid = (pthread_t)-1;
+static volatile boolean_t _reap_children_stop;
+static avl_tree_t _launched_processes;
+static pthread_mutex_t _launched_processes_lock = PTHREAD_MUTEX_INITIALIZER;
+static int16_t _launched_processes_limit;
+
+/*
+ * Create an environment string array for passing to execve() using the
+ * NAME=VALUE strings in container [zsp].
+ * Return a newly-allocated environment, or NULL on error.
+ */
+static char **
+_zed_exec_create_env(zed_strings_t *zsp)
+{
+	int num_ptrs;
+	int buflen;
+	char *buf;
+	char **pp;
+	char *p;
+	const char *q;
+	int i;
+	int len;
+
+	num_ptrs = zed_strings_count(zsp) + 1;
+	buflen = num_ptrs * sizeof (char *);
+	for (q = zed_strings_first(zsp); q; q = zed_strings_next(zsp))
+		buflen += strlen(q) + 1;
+
+	buf = calloc(1, buflen);
+	if (!buf)
+		return (NULL);
+
+	pp = (char **)buf;
+	p = buf + (num_ptrs * sizeof (char *));
+	i = 0;
+	for (q = zed_strings_first(zsp); q; q = zed_strings_next(zsp)) {
+		pp[i] = p;
+		len = strlen(q) + 1;
+		memcpy(p, q, len);
+		p += len;
+		i++;
+	}
+	pp[i] = NULL;
+	assert(buf + buflen == p);
+	return ((char **)buf);
+}
+
+/*
+ * Fork a child process to handle event [eid].  The program [prog]
+ * in directory [dir] is executed with the environment [env].
+ *
+ * The file descriptor [zfd] is the zevent_fd used to track the
+ * current cursor location within the zevent nvlist.
+ */
+static void
+_zed_exec_fork_child(uint64_t eid, const char *dir, const char *prog,
+    char *env[], int zfd, boolean_t in_foreground)
+{
+	char path[PATH_MAX];
+	int n;
+	pid_t pid;
+	int fd;
+	struct launched_process_node *node;
+	sigset_t mask;
+	struct timespec launch_timeout =
+		{ .tv_sec = 0, .tv_nsec = 200 * 1000 * 1000, };
+
+	assert(dir != NULL);
+	assert(prog != NULL);
+	assert(env != NULL);
+	assert(zfd >= 0);
+
+	while (__atomic_load_n(&_launched_processes_limit,
+	    __ATOMIC_SEQ_CST) <= 0)
+		(void) nanosleep(&launch_timeout, NULL);
+
+	n = snprintf(path, sizeof (path), "%s/%s", dir, prog);
+	if ((n < 0) || (n >= sizeof (path))) {
+		zed_log_msg(LOG_WARNING,
+		    "Failed to fork \"%s\" for eid=%llu: %s",
+		    prog, eid, strerror(ENAMETOOLONG));
+		return;
+	}
+	(void) pthread_mutex_lock(&_launched_processes_lock);
+	pid = fork();
+	if (pid < 0) {
+		(void) pthread_mutex_unlock(&_launched_processes_lock);
+		zed_log_msg(LOG_WARNING,
+		    "Failed to fork \"%s\" for eid=%llu: %s",
+		    prog, eid, strerror(errno));
+		return;
+	} else if (pid == 0) {
+		(void) sigemptyset(&mask);
+		(void) sigprocmask(SIG_SETMASK, &mask, NULL);
+
+		(void) umask(022);
+		if (in_foreground && /* we're already devnulled if daemonised */
+		    (fd = open("/dev/null", O_RDWR | O_CLOEXEC)) != -1) {
+			(void) dup2(fd, STDIN_FILENO);
+			(void) dup2(fd, STDOUT_FILENO);
+			(void) dup2(fd, STDERR_FILENO);
+		}
+		(void) dup2(zfd, ZEVENT_FILENO);
+		execle(path, prog, NULL, env);
+		_exit(127);
+	}
+
+	/* parent process */
+
+	node = calloc(1, sizeof (*node));
+	if (node) {
+		node->pid = pid;
+		node->eid = eid;
+		node->name = strdup(prog);
+		if (node->name == NULL) {
+			perror("strdup");
+			exit(EXIT_FAILURE);
+		}
+
+		avl_add(&_launched_processes, node);
+	}
+	(void) pthread_mutex_unlock(&_launched_processes_lock);
+
+	__atomic_sub_fetch(&_launched_processes_limit, 1, __ATOMIC_SEQ_CST);
+	zed_log_msg(LOG_INFO, "Invoking \"%s\" eid=%llu pid=%d",
+	    prog, eid, pid);
+}
+
+static void
+_nop(int sig)
+{
+	(void) sig;
+}
+
+static void
+wait_for_children(boolean_t do_pause, boolean_t wait)
+{
+	pid_t pid;
+	struct rusage usage;
+	int status;
+	struct launched_process_node node, *pnode;
+
+	for (_reap_children_stop = B_FALSE; !_reap_children_stop; ) {
+		(void) pthread_mutex_lock(&_launched_processes_lock);
+		pid = wait4(0, &status, wait ? 0 : WNOHANG, &usage);
+		if (pid == 0 || pid == (pid_t)-1) {
+			(void) pthread_mutex_unlock(&_launched_processes_lock);
+			if ((pid == 0) || (errno == ECHILD)) {
+				if (do_pause)
+					pause();
+			} else if (errno != EINTR)
+				zed_log_msg(LOG_WARNING,
+				    "Failed to wait for children: %s",
+				    strerror(errno));
+			if (!do_pause)
+				return;
+
+		} else {
+			memset(&node, 0, sizeof (node));
+			node.pid = pid;
+			pnode = avl_find(&_launched_processes, &node, NULL);
+			if (pnode) {
+				memcpy(&node, pnode, sizeof (node));
+
+				avl_remove(&_launched_processes, pnode);
+				free(pnode);
+			}
+			(void) pthread_mutex_unlock(&_launched_processes_lock);
+			__atomic_add_fetch(&_launched_processes_limit, 1,
+			    __ATOMIC_SEQ_CST);
+
+			usage.ru_utime.tv_sec += usage.ru_stime.tv_sec;
+			usage.ru_utime.tv_usec += usage.ru_stime.tv_usec;
+			usage.ru_utime.tv_sec +=
+			    usage.ru_utime.tv_usec / (1000 * 1000);
+			usage.ru_utime.tv_usec %= 1000 * 1000;
+
+			if (WIFEXITED(status)) {
+				zed_log_msg(LOG_INFO,
+				    "Finished \"%s\" eid=%llu pid=%d "
+				    "time=%llu.%06us exit=%d",
+				    node.name, node.eid, pid,
+				    (unsigned long long) usage.ru_utime.tv_sec,
+				    (unsigned int) usage.ru_utime.tv_usec,
+				    WEXITSTATUS(status));
+			} else if (WIFSIGNALED(status)) {
+				zed_log_msg(LOG_INFO,
+				    "Finished \"%s\" eid=%llu pid=%d "
+				    "time=%llu.%06us sig=%d/%s",
+				    node.name, node.eid, pid,
+				    (unsigned long long) usage.ru_utime.tv_sec,
+				    (unsigned int) usage.ru_utime.tv_usec,
+				    WTERMSIG(status),
+				    strsignal(WTERMSIG(status)));
+			} else {
+				zed_log_msg(LOG_INFO,
+				    "Finished \"%s\" eid=%llu pid=%d "
+				    "time=%llu.%06us status=0x%X",
+				    node.name, node.eid, pid,
+				    (unsigned long long) usage.ru_utime.tv_sec,
+				    (unsigned int) usage.ru_utime.tv_usec,
+				    (unsigned int) status);
+			}
+
+			free(node.name);
+		}
+	}
+
+}
+
+static void *
+_reap_children(void *arg)
+{
+	(void) arg;
+	struct sigaction sa = {};
+
+	(void) sigfillset(&sa.sa_mask);
+	(void) sigdelset(&sa.sa_mask, SIGCHLD);
+	(void) pthread_sigmask(SIG_SETMASK, &sa.sa_mask, NULL);
+
+	(void) sigemptyset(&sa.sa_mask);
+	sa.sa_handler = _nop;
+	sa.sa_flags = SA_NOCLDSTOP;
+	(void) sigaction(SIGCHLD, &sa, NULL);
+
+	wait_for_children(B_TRUE, B_FALSE);
+
+	return (NULL);
+}
+
+void
+zed_exec_fini(void)
+{
+	struct launched_process_node *node;
+	void *ck = NULL;
+
+	if (_reap_children_tid == (pthread_t)-1)
+		return;
+
+	_reap_children_stop = B_TRUE;
+	(void) pthread_kill(_reap_children_tid, SIGCHLD);
+	(void) pthread_join(_reap_children_tid, NULL);
+
+	while ((node = avl_destroy_nodes(&_launched_processes, &ck)) != NULL) {
+		free(node->name);
+		free(node);
+	}
+	avl_destroy(&_launched_processes);
+
+	(void) pthread_mutex_destroy(&_launched_processes_lock);
+	(void) pthread_mutex_init(&_launched_processes_lock, NULL);
+
+	_reap_children_tid = (pthread_t)-1;
+}
+
+/*
+ * Check if the zedlet name indicates if it is a synchronous zedlet
+ *
+ * Synchronous zedlets have a "-sync-" immediately following the event name in
+ * their zedlet filename, like:
+ *
+ * EVENT_NAME-sync-ZEDLETNAME.sh
+ *
+ * For example, if you wanted a synchronous statechange script:
+ *
+ * statechange-sync-myzedlet.sh
+ *
+ * Synchronous zedlets are guaranteed to be the only zedlet running.  No other
+ * zedlets may run in parallel with a synchronous zedlet.  A synchronous
+ * zedlet will wait for all previously spawned zedlets to finish before running.
+ * Users should be careful to only use synchronous zedlets when needed, since
+ * they decrease parallelism.
+ */
+static boolean_t
+zedlet_is_sync(const char *zedlet, const char *event)
+{
+	const char *sync_str = "-sync-";
+	size_t sync_str_len;
+	size_t zedlet_len;
+	size_t event_len;
+
+	sync_str_len = strlen(sync_str);
+	zedlet_len = strlen(zedlet);
+	event_len = strlen(event);
+
+	if (event_len + sync_str_len >= zedlet_len)
+		return (B_FALSE);
+
+	if (strncmp(&zedlet[event_len], sync_str, sync_str_len) == 0)
+		return (B_TRUE);
+
+	return (B_FALSE);
+}
+
+/*
+ * Process the event [eid] by synchronously invoking all zedlets with a
+ * matching class prefix.
+ *
+ * Each executable in [zcp->zedlets] from the directory [zcp->zedlet_dir]
+ * is matched against the event's [class], [subclass], and the "all" class
+ * (which matches all events).
+ * Every zedlet with a matching class prefix is invoked.
+ * The NAME=VALUE strings in [envs] will be passed to the zedlet as
+ * environment variables.
+ *
+ * The file descriptor [zcp->zevent_fd] is the zevent_fd used to track the
+ * current cursor location within the zevent nvlist.
+ *
+ * Return 0 on success, -1 on error.
+ */
+int
+zed_exec_process(uint64_t eid, const char *class, const char *subclass,
+    struct zed_conf *zcp, zed_strings_t *envs)
+{
+	const char *class_strings[4];
+	const char *allclass = "all";
+	const char **csp;
+	const char *z;
+	char **e;
+	int n;
+
+	if (!zcp->zedlet_dir || !zcp->zedlets || !envs || zcp->zevent_fd < 0)
+		return (-1);
+
+	if (_reap_children_tid == (pthread_t)-1) {
+		_launched_processes_limit = zcp->max_jobs;
+
+		if (pthread_create(&_reap_children_tid, NULL,
+		    _reap_children, NULL) != 0)
+			return (-1);
+		pthread_setname_np(_reap_children_tid, "reap ZEDLETs");
+
+		avl_create(&_launched_processes, _launched_process_node_compare,
+		    sizeof (struct launched_process_node),
+		    offsetof(struct launched_process_node, node));
+	}
+
+	csp = class_strings;
+
+	if (class)
+		*csp++ = class;
+
+	if (subclass)
+		*csp++ = subclass;
+
+	if (allclass)
+		*csp++ = allclass;
+
+	*csp = NULL;
+
+	e = _zed_exec_create_env(envs);
+
+	for (z = zed_strings_first(zcp->zedlets); z;
+	    z = zed_strings_next(zcp->zedlets)) {
+		for (csp = class_strings; *csp; csp++) {
+			n = strlen(*csp);
+			if ((strncmp(z, *csp, n) == 0) && !isalpha(z[n])) {
+				boolean_t is_sync = zedlet_is_sync(z, *csp);
+
+				if (is_sync) {
+					/*
+					 * Wait for previous zedlets to
+					 * finish
+					 */
+					wait_for_children(B_FALSE, B_TRUE);
+				}
+
+				_zed_exec_fork_child(eid, zcp->zedlet_dir,
+				    z, e, zcp->zevent_fd, zcp->do_foreground);
+
+				if (is_sync) {
+					/*
+					 * Wait for sync zedlet we just launched
+					 * to finish.
+					 */
+					wait_for_children(B_FALSE, B_TRUE);
+				}
+			}
+		}
+	}
+	free(e);
+	return (0);
+}