From 62689d8166b8e070f855e6910470796dd7e1b2c8 Mon Sep 17 00:00:00 2001
From: Volker Lendecke <vl@samba.org>
Date: Fri, 22 Apr 2011 11:47:11 +0200
Subject: s3: Many pthreadpool fixes

In particular, this makes it fork-safe
---
 source3/lib/fncall.c                  |   2 +-
 source3/lib/pthreadpool.c             | 505 -----------------------------
 source3/lib/pthreadpool/Makefile      |   9 +
 source3/lib/pthreadpool/pthreadpool.c | 592 ++++++++++++++++++++++++++++++++++
 source3/lib/pthreadpool/pthreadpool.h |  42 +++
 source3/lib/pthreadpool/tests.c       | 362 +++++++++++++++++++++
 6 files changed, 1006 insertions(+), 506 deletions(-)
 delete mode 100644 source3/lib/pthreadpool.c
 create mode 100644 source3/lib/pthreadpool/Makefile
 create mode 100644 source3/lib/pthreadpool/pthreadpool.c
 create mode 100644 source3/lib/pthreadpool/pthreadpool.h
 create mode 100644 source3/lib/pthreadpool/tests.c

(limited to 'source3/lib')

diff --git a/source3/lib/fncall.c b/source3/lib/fncall.c
index e810b6814e..bd06be2cd8 100644
--- a/source3/lib/fncall.c
+++ b/source3/lib/fncall.c
@@ -21,7 +21,7 @@
 
 #if WITH_PTHREADPOOL
 
-#include "pthreadpool.h"
+#include "lib/pthreadpool/pthreadpool.h"
 
 struct fncall_state {
 	struct fncall_context *ctx;
diff --git a/source3/lib/pthreadpool.c b/source3/lib/pthreadpool.c
deleted file mode 100644
index b62bab0a2e..0000000000
--- a/source3/lib/pthreadpool.c
+++ /dev/null
@@ -1,505 +0,0 @@
-/*
- * Unix SMB/CIFS implementation.
- * thread pool implementation
- * Copyright (C) Volker Lendecke 2009
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <errno.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <stdlib.h>
-#include <string.h>
-#include <pthread.h>
-#include <signal.h>
-#include <assert.h>
-#include <fcntl.h>
-
-#include "pthreadpool.h"
-
-struct pthreadpool_job {
-	struct pthreadpool_job *next;
-	int id;
-	void (*fn)(void *private_data);
-	void *private_data;
-};
-
-struct pthreadpool {
-	/*
-	 * Control access to this struct
-	 */
-	pthread_mutex_t mutex;
-
-	/*
-	 * Threads waiting for work do so here
-	 */
-	pthread_cond_t condvar;
-
-	/*
-	 * List of work jobs
-	 */
-	struct pthreadpool_job *jobs, *last_job;
-
-	/*
-	 * pipe for signalling
-	 */
-	int sig_pipe[2];
-
-	/*
-	 * indicator to worker threads that they should shut down
-	 */
-	int shutdown;
-
-	/*
-	 * maximum number of threads
-	 */
-	int max_threads;
-
-	/*
-	 * Number of threads
-	 */
-	int num_threads;
-
-	/*
-	 * Number of idle threads
-	 */
-	int num_idle;
-
-	/*
-	 * An array of threads that require joining, the array has
-	 * "max_threads" elements. It contains "num_exited" ids.
-	 */
-	int			num_exited;
-	pthread_t		exited[1]; /* We alloc more */
-};
-
-/*
- * Initialize a thread pool
- */
-
-int pthreadpool_init(unsigned max_threads, struct pthreadpool **presult)
-{
-	struct pthreadpool *pool;
-	size_t size;
-	int ret;
-
-	size = sizeof(struct pthreadpool) + max_threads * sizeof(pthread_t);
-
-	pool = (struct pthreadpool *)malloc(size);
-	if (pool == NULL) {
-		return ENOMEM;
-	}
-
-	ret = pthread_mutex_init(&pool->mutex, NULL);
-	if (ret != 0) {
-		free(pool);
-		return ret;
-	}
-
-	ret = pthread_cond_init(&pool->condvar, NULL);
-	if (ret != 0) {
-		pthread_mutex_destroy(&pool->mutex);
-		free(pool);
-		return ret;
-	}
-
-	pool->shutdown = 0;
-	pool->jobs = pool->last_job = NULL;
-	pool->num_threads = 0;
-	pool->num_exited = 0;
-	pool->max_threads = max_threads;
-	pool->num_idle = 0;
-	pool->sig_pipe[0] = -1;
-	pool->sig_pipe[1] = -1;
-
-	*presult = pool;
-	return 0;
-}
-
-/*
- * Create and return a file descriptor which becomes readable when a job has
- * finished
- */
-
-int pthreadpool_sig_fd(struct pthreadpool *pool)
-{
-	int result, ret;
-
-	ret = pthread_mutex_lock(&pool->mutex);
-	if (ret != 0) {
-		errno = ret;
-		return -1;
-	}
-
-	if (pool->sig_pipe[0] != -1) {
-		result = pool->sig_pipe[0];
-		goto done;
-	}
-
-	ret = pipe(pool->sig_pipe);
-	if (ret == -1) {
-		result = -1;
-		goto done;
-	}
-
-	result = pool->sig_pipe[0];
-done:
-	ret = pthread_mutex_unlock(&pool->mutex);
-	assert(ret == 0);
-	return result;
-}
-
-/*
- * Do a pthread_join() on all children that have exited, pool->mutex must be
- * locked
- */
-static void pthreadpool_join_children(struct pthreadpool *pool)
-{
-	int i;
-
-	for (i=0; i<pool->num_exited; i++) {
-		pthread_join(pool->exited[i], NULL);
-	}
-	pool->num_exited = 0;
-}
-
-/*
- * Fetch a finished job number from the signal pipe
- */
-
-int pthreadpool_finished_job(struct pthreadpool *pool)
-{
-	int result, ret, fd;
-	ssize_t nread;
-
-	ret = pthread_mutex_lock(&pool->mutex);
-	if (ret != 0) {
-		errno = ret;
-		return -1;
-	}
-
-	/*
-	 * Just some cleanup under the mutex
-	 */
-	pthreadpool_join_children(pool);
-
-	fd = pool->sig_pipe[0];
-
-	ret = pthread_mutex_unlock(&pool->mutex);
-	assert(ret == 0);
-
-	if (fd == -1) {
-		errno = EINVAL;
-		return -1;
-	}
-
-	nread = -1;
-	errno = EINTR;
-
-	while ((nread == -1) && (errno == EINTR)) {
-		nread = read(fd, &result, sizeof(int));
-	}
-
-	/*
-	 * TODO: handle nread > 0 && nread < sizeof(int)
-	 */
-
-	/*
-	 * Lock the mutex to provide a memory barrier for data from the worker
-	 * thread to the main thread. The pipe access itself does not have to
-	 * be locked, for sizeof(int) the write to a pipe is atomic, and only
-	 * one thread reads from it. But we need to lock the mutex briefly
-	 * even if we don't do anything under the lock, to make sure we can
-	 * see all memory the helper thread has written.
-	 */
-
-	ret = pthread_mutex_lock(&pool->mutex);
-	if (ret == -1) {
-		errno = ret;
-		return -1;
-	}
-
-	ret = pthread_mutex_unlock(&pool->mutex);
-	assert(ret == 0);
-
-	return result;
-}
-
-/*
- * Destroy a thread pool, finishing all threads working for it
- */
-
-int pthreadpool_destroy(struct pthreadpool *pool)
-{
-	int ret, ret1;
-
-	ret = pthread_mutex_lock(&pool->mutex);
-	if (ret != 0) {
-		return ret;
-	}
-
-	if (pool->num_threads > 0) {
-		/*
-		 * We have active threads, tell them to finish, wait for that.
-		 */
-
-		pool->shutdown = 1;
-
-		if (pool->num_idle > 0) {
-			/*
-			 * Wake the idle threads. They will find pool->quit to
-			 * be set and exit themselves
-			 */
-			ret = pthread_cond_broadcast(&pool->condvar);
-			if (ret != 0) {
-				pthread_mutex_unlock(&pool->mutex);
-				return ret;
-			}
-		}
-
-		while ((pool->num_threads > 0) || (pool->num_exited > 0)) {
-
-			if (pool->num_exited > 0) {
-				pthreadpool_join_children(pool);
-				continue;
-			}
-			/*
-			 * A thread that shuts down will also signal
-			 * pool->condvar
-			 */
-			ret = pthread_cond_wait(&pool->condvar, &pool->mutex);
-			if (ret != 0) {
-				pthread_mutex_unlock(&pool->mutex);
-				return ret;
-			}
-		}
-	}
-
-	ret = pthread_mutex_unlock(&pool->mutex);
-	if (ret != 0) {
-		return ret;
-	}
-	ret = pthread_mutex_destroy(&pool->mutex);
-	ret1 = pthread_cond_destroy(&pool->condvar);
-
-	if ((ret == 0) && (ret1 == 0)) {
-		free(pool);
-	}
-
-	if (ret != 0) {
-		return ret;
-	}
-	return ret1;
-}
-
-/*
- * Prepare for pthread_exit(), pool->mutex must be locked
- */
-static void pthreadpool_server_exit(struct pthreadpool *pool)
-{
-	pool->num_threads -= 1;
-	pool->exited[pool->num_exited] = pthread_self();
-	pool->num_exited += 1;
-}
-
-static void *pthreadpool_server(void *arg)
-{
-	struct pthreadpool *pool = (struct pthreadpool *)arg;
-	int res;
-
-	res = pthread_mutex_lock(&pool->mutex);
-	if (res != 0) {
-		return NULL;
-	}
-
-	while (1) {
-		struct timespec timeout;
-		struct pthreadpool_job *job;
-
-		/*
-		 * idle-wait at most 1 second. If nothing happens in that
-		 * time, exit this thread.
-		 */
-
-		timeout.tv_sec = time(NULL) + 1;
-		timeout.tv_nsec = 0;
-
-		while ((pool->jobs == NULL) && (pool->shutdown == 0)) {
-
-			pool->num_idle += 1;
-			res = pthread_cond_timedwait(
-				&pool->condvar, &pool->mutex, &timeout);
-			pool->num_idle -= 1;
-
-			if (res == ETIMEDOUT) {
-
-				if (pool->jobs == NULL) {
-					/*
-					 * we timed out and still no work for
-					 * us. Exit.
-					 */
-					pthreadpool_server_exit(pool);
-					pthread_mutex_unlock(&pool->mutex);
-					return NULL;
-				}
-
-				break;
-			}
-			assert(res == 0);
-		}
-
-		job = pool->jobs;
-
-		if (job != NULL) {
-			int fd = pool->sig_pipe[1];
-			ssize_t written;
-
-			/*
-			 * Ok, there's work for us to do, remove the job from
-			 * the pthreadpool list
-			 */
-			pool->jobs = job->next;
-			if (pool->last_job == job) {
-				pool->last_job = NULL;
-			}
-
-			/*
-			 * Do the work with the mutex unlocked :-)
-			 */
-
-			res = pthread_mutex_unlock(&pool->mutex);
-			assert(res == 0);
-
-			job->fn(job->private_data);
-
-			written = sizeof(int);
-
-			res = pthread_mutex_lock(&pool->mutex);
-			assert(res == 0);
-
-			if (fd != -1) {
-				written = write(fd, &job->id, sizeof(int));
-			}
-
-			free(job);
-
-			if (written != sizeof(int)) {
-				pthreadpool_server_exit(pool);
-				pthread_mutex_unlock(&pool->mutex);
-				return NULL;
-			}
-		}
-
-		if ((pool->jobs == NULL) && (pool->shutdown != 0)) {
-			/*
-			 * No more work to do and we're asked to shut down, so
-			 * exit
-			 */
-			pthreadpool_server_exit(pool);
-
-			if (pool->num_threads == 0) {
-				/*
-				 * Ping the main thread waiting for all of us
-				 * workers to have quit.
-				 */
-				pthread_cond_broadcast(&pool->condvar);
-			}
-
-			pthread_mutex_unlock(&pool->mutex);
-			return NULL;
-		}
-	}
-}
-
-int pthreadpool_add_job(struct pthreadpool *pool, int job_id,
-			void (*fn)(void *private_data), void *private_data)
-{
-	struct pthreadpool_job *job;
-	pthread_t thread_id;
-	int res;
-	sigset_t mask, omask;
-
-	job = (struct pthreadpool_job *)malloc(sizeof(struct pthreadpool_job));
-	if (job == NULL) {
-		return ENOMEM;
-	}
-
-	job->fn = fn;
-	job->private_data = private_data;
-	job->id = job_id;
-	job->next = NULL;
-
-	res = pthread_mutex_lock(&pool->mutex);
-	if (res != 0) {
-		free(job);
-		return res;
-	}
-
-	/*
-	 * Just some cleanup under the mutex
-	 */
-	pthreadpool_join_children(pool);
-
-	/*
-	 * Add job to the end of the queue
-	 */
-	if (pool->jobs == NULL) {
-		pool->jobs = job;
-	}
-	else {
-		pool->last_job->next = job;
-	}
-	pool->last_job = job;
-
-	if (pool->num_idle > 0) {
-		/*
-		 * We have idle threads, wake one.
-		 */
-		res = pthread_cond_signal(&pool->condvar);
-		pthread_mutex_unlock(&pool->mutex);
-		return res;
-	}
-
-	if (pool->num_threads >= pool->max_threads) {
-		/*
-		 * No more new threads, we just queue the request
-		 */
-		pthread_mutex_unlock(&pool->mutex);
-		return 0;
-	}
-
-	/*
-	 * Create a new worker thread. It should not receive any signals.
-	 */
-
-	sigfillset(&mask);
-
-        res = pthread_sigmask(SIG_BLOCK, &mask, &omask);
-	if (res != 0) {
-		pthread_mutex_unlock(&pool->mutex);
-		return res;
-	}
-
-	res = pthread_create(&thread_id, NULL, pthreadpool_server,
-				(void *)pool);
-	if (res == 0) {
-		pool->num_threads += 1;
-	}
-
-        assert(pthread_sigmask(SIG_SETMASK, &omask, NULL) == 0);
-
-	pthread_mutex_unlock(&pool->mutex);
-	return res;
-}
diff --git a/source3/lib/pthreadpool/Makefile b/source3/lib/pthreadpool/Makefile
new file mode 100644
index 0000000000..48626bd2c0
--- /dev/null
+++ b/source3/lib/pthreadpool/Makefile
@@ -0,0 +1,9 @@
+all: tests
+
+CFLAGS=-O3 -g -Wall
+
+pthreadpool.o: pthreadpool.c pthreadpool.h
+	gcc -c -O3 -o pthreadpool.o pthreadpool.c -I../../..
+
+tests: tests.o pthreadpool.o
+	gcc -o tests tests.o pthreadpool.o -lpthread
\ No newline at end of file
diff --git a/source3/lib/pthreadpool/pthreadpool.c b/source3/lib/pthreadpool/pthreadpool.c
new file mode 100644
index 0000000000..4605538cf2
--- /dev/null
+++ b/source3/lib/pthreadpool/pthreadpool.c
@@ -0,0 +1,592 @@
+/*
+ * Unix SMB/CIFS implementation.
+ * thread pool implementation
+ * Copyright (C) Volker Lendecke 2009
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <pthread.h>
+#include <signal.h>
+#include <assert.h>
+#include <fcntl.h>
+#include <sys/time.h>
+
+#include "pthreadpool.h"
+#include "lib/util/dlinklist.h"
+
+struct pthreadpool_job {
+	struct pthreadpool_job *next;
+	int id;
+	void (*fn)(void *private_data);
+	void *private_data;
+};
+
+struct pthreadpool {
+	/*
+	 * List pthreadpools for fork safety
+	 */
+	struct pthreadpool *prev, *next;
+
+	/*
+	 * Control access to this struct
+	 */
+	pthread_mutex_t mutex;
+
+	/*
+	 * Threads waiting for work do so here
+	 */
+	pthread_cond_t condvar;
+
+	/*
+	 * List of work jobs
+	 */
+	struct pthreadpool_job *jobs, *last_job;
+
+	/*
+	 * pipe for signalling
+	 */
+	int sig_pipe[2];
+
+	/*
+	 * indicator to worker threads that they should shut down
+	 */
+	int shutdown;
+
+	/*
+	 * maximum number of threads
+	 */
+	int max_threads;
+
+	/*
+	 * Number of threads
+	 */
+	int num_threads;
+
+	/*
+	 * Number of idle threads
+	 */
+	int num_idle;
+
+	/*
+	 * An array of threads that require joining, the array has
+	 * "max_threads" elements. It contains "num_exited" ids.
+	 */
+	int			num_exited;
+	pthread_t		exited[1]; /* We alloc more */
+};
+
+static pthread_mutex_t pthreadpools_mutex = PTHREAD_MUTEX_INITIALIZER;
+static struct pthreadpool *pthreadpools = NULL;
+static pthread_once_t pthreadpool_atfork_initialized = PTHREAD_ONCE_INIT;
+
+static void pthreadpool_prep_atfork(void);
+
+/*
+ * Initialize a thread pool
+ */
+
+int pthreadpool_init(unsigned max_threads, struct pthreadpool **presult)
+{
+	struct pthreadpool *pool;
+	size_t size;
+	int ret;
+
+	size = sizeof(struct pthreadpool)
+		+ (max_threads-1) * sizeof(pthread_t);
+
+	pool = (struct pthreadpool *)malloc(size);
+	if (pool == NULL) {
+		return ENOMEM;
+	}
+
+	ret = pipe(pool->sig_pipe);
+	if (ret == -1) {
+		int err = errno;
+		free(pool);
+		return err;
+	}
+
+	ret = pthread_mutex_init(&pool->mutex, NULL);
+	if (ret != 0) {
+		free(pool);
+		return ret;
+	}
+
+	ret = pthread_cond_init(&pool->condvar, NULL);
+	if (ret != 0) {
+		pthread_mutex_destroy(&pool->mutex);
+		free(pool);
+		return ret;
+	}
+
+	pool->shutdown = 0;
+	pool->jobs = pool->last_job = NULL;
+	pool->num_threads = 0;
+	pool->num_exited = 0;
+	pool->max_threads = max_threads;
+	pool->num_idle = 0;
+
+	ret = pthread_mutex_lock(&pthreadpools_mutex);
+	if (ret != 0) {
+		pthread_cond_destroy(&pool->condvar);
+		pthread_mutex_destroy(&pool->mutex);
+		free(pool);
+		return ret;
+	}
+	DLIST_ADD(pthreadpools, pool);
+
+	ret = pthread_mutex_unlock(&pthreadpools_mutex);
+	assert(ret == 0);
+
+	pthread_once(&pthreadpool_atfork_initialized, pthreadpool_prep_atfork);
+
+	*presult = pool;
+
+	return 0;
+}
+
+static void pthreadpool_prepare(void)
+{
+	int ret;
+	struct pthreadpool *pool;
+
+	ret = pthread_mutex_lock(&pthreadpools_mutex);
+	assert(ret == 0);
+
+	pool = pthreadpools;
+
+	while (pool != NULL) {
+		ret = pthread_mutex_lock(&pool->mutex);
+		assert(ret == 0);
+		pool = pool->next;
+	}
+}
+
+static void pthreadpool_parent(void)
+{
+	int ret;
+	struct pthreadpool *pool;
+
+	pool = DLIST_TAIL(pthreadpools);
+
+	while (1) {
+		ret = pthread_mutex_unlock(&pool->mutex);
+		assert(ret == 0);
+
+		if (pool == pthreadpools) {
+			break;
+		}
+		pool = pool->prev;
+	}
+
+	ret = pthread_mutex_unlock(&pthreadpools_mutex);
+	assert(ret == 0);
+}
+
+static void pthreadpool_child(void)
+{
+	int ret;
+	struct pthreadpool *pool;
+
+	pool = DLIST_TAIL(pthreadpools);
+
+	while (1) {
+		close(pool->sig_pipe[0]);
+		close(pool->sig_pipe[1]);
+
+		ret = pipe(pool->sig_pipe);
+		assert(ret == 0);
+
+		pool->num_threads = 0;
+		pool->num_exited = 0;
+		pool->num_idle = 0;
+
+		while (pool->jobs != NULL) {
+			struct pthreadpool_job *job;
+			job = pool->jobs;
+			pool->jobs = job->next;
+			free(job);
+		}
+		pool->last_job = NULL;
+
+		ret = pthread_mutex_unlock(&pool->mutex);
+		assert(ret == 0);
+
+		if (pool == pthreadpools) {
+			break;
+		}
+		pool = pool->prev;
+	}
+
+	ret = pthread_mutex_unlock(&pthreadpools_mutex);
+	assert(ret == 0);
+}
+
+static void pthreadpool_prep_atfork(void)
+{
+	pthread_atfork(pthreadpool_prepare, pthreadpool_parent,
+		       pthreadpool_child);
+}
+
+/*
+ * Return the file descriptor which becomes readable when a job has
+ * finished
+ */
+
+int pthreadpool_sig_fd(struct pthreadpool *pool)
+{
+	return pool->sig_pipe[0];
+}
+
+/*
+ * Do a pthread_join() on all children that have exited, pool->mutex must be
+ * locked
+ */
+static void pthreadpool_join_children(struct pthreadpool *pool)
+{
+	int i;
+
+	for (i=0; i<pool->num_exited; i++) {
+		pthread_join(pool->exited[i], NULL);
+	}
+	pool->num_exited = 0;
+}
+
+/*
+ * Fetch a finished job number from the signal pipe
+ */
+
+int pthreadpool_finished_job(struct pthreadpool *pool)
+{
+	int result;
+	ssize_t nread;
+
+	nread = -1;
+	errno = EINTR;
+
+	while ((nread == -1) && (errno == EINTR)) {
+		nread = read(pool->sig_pipe[0], &result, sizeof(int));
+	}
+	if (nread == -1) {
+		return errno;
+	}
+	if (nread != sizeof(int)) {
+		return EINVAL;
+	}
+	return result;
+}
+
+/*
+ * Destroy a thread pool, finishing all threads working for it
+ */
+
+int pthreadpool_destroy(struct pthreadpool *pool)
+{
+	int ret, ret1;
+
+	ret = pthread_mutex_lock(&pool->mutex);
+	if (ret != 0) {
+		return ret;
+	}
+
+	if ((pool->jobs != NULL) || pool->shutdown) {
+		ret = pthread_mutex_unlock(&pool->mutex);
+		assert(ret == 0);
+		return EBUSY;
+	}
+
+	if (pool->num_threads > 0) {
+		/*
+		 * We have active threads, tell them to finish, wait for that.
+		 */
+
+		pool->shutdown = 1;
+
+		if (pool->num_idle > 0) {
+			/*
+			 * Wake the idle threads. They will find pool->quit to
+			 * be set and exit themselves
+			 */
+			ret = pthread_cond_broadcast(&pool->condvar);
+			if (ret != 0) {
+				pthread_mutex_unlock(&pool->mutex);
+				return ret;
+			}
+		}
+
+		while ((pool->num_threads > 0) || (pool->num_exited > 0)) {
+
+			if (pool->num_exited > 0) {
+				pthreadpool_join_children(pool);
+				continue;
+			}
+			/*
+			 * A thread that shuts down will also signal
+			 * pool->condvar
+			 */
+			ret = pthread_cond_wait(&pool->condvar, &pool->mutex);
+			if (ret != 0) {
+				pthread_mutex_unlock(&pool->mutex);
+				return ret;
+			}
+		}
+	}
+
+	ret = pthread_mutex_unlock(&pool->mutex);
+	if (ret != 0) {
+		return ret;
+	}
+	ret = pthread_mutex_destroy(&pool->mutex);
+	ret1 = pthread_cond_destroy(&pool->condvar);
+
+	if (ret != 0) {
+		return ret;
+	}
+	if (ret1 != 0) {
+		return ret1;
+	}
+
+	ret = pthread_mutex_lock(&pthreadpools_mutex);
+	if (ret != 0) {
+		return ret;
+	}
+	DLIST_REMOVE(pthreadpools, pool);
+	ret = pthread_mutex_unlock(&pthreadpools_mutex);
+	assert(ret == 0);
+
+	close(pool->sig_pipe[0]);
+	pool->sig_pipe[0] = -1;
+
+	close(pool->sig_pipe[1]);
+	pool->sig_pipe[1] = -1;
+
+	free(pool);
+
+	return 0;
+}
+
+/*
+ * Prepare for pthread_exit(), pool->mutex must be locked
+ */
+static void pthreadpool_server_exit(struct pthreadpool *pool)
+{
+	pool->num_threads -= 1;
+	pool->exited[pool->num_exited] = pthread_self();
+	pool->num_exited += 1;
+}
+
+static void *pthreadpool_server(void *arg)
+{
+	struct pthreadpool *pool = (struct pthreadpool *)arg;
+	int res;
+
+	res = pthread_mutex_lock(&pool->mutex);
+	if (res != 0) {
+		return NULL;
+	}
+
+	while (1) {
+		struct timeval tv;
+		struct timespec ts;
+		struct pthreadpool_job *job;
+
+		/*
+		 * idle-wait at most 1 second. If nothing happens in that
+		 * time, exit this thread.
+		 */
+
+		gettimeofday(&tv, NULL);
+		ts.tv_sec = tv.tv_sec + 1;
+		ts.tv_nsec = tv.tv_usec*1000;
+
+		while ((pool->jobs == NULL) && (pool->shutdown == 0)) {
+
+			pool->num_idle += 1;
+			res = pthread_cond_timedwait(
+				&pool->condvar, &pool->mutex, &ts);
+			pool->num_idle -= 1;
+
+			if (res == ETIMEDOUT) {
+
+				if (pool->jobs == NULL) {
+					/*
+					 * we timed out and still no work for
+					 * us. Exit.
+					 */
+					pthreadpool_server_exit(pool);
+					pthread_mutex_unlock(&pool->mutex);
+					return NULL;
+				}
+
+				break;
+			}
+			assert(res == 0);
+		}
+
+		job = pool->jobs;
+
+		if (job != NULL) {
+			ssize_t written;
+
+			/*
+			 * Ok, there's work for us to do, remove the job from
+			 * the pthreadpool list
+			 */
+			pool->jobs = job->next;
+			if (pool->last_job == job) {
+				pool->last_job = NULL;
+			}
+
+			/*
+			 * Do the work with the mutex unlocked
+			 */
+
+			res = pthread_mutex_unlock(&pool->mutex);
+			assert(res == 0);
+
+			job->fn(job->private_data);
+
+			written = write(pool->sig_pipe[1], &job->id,
+					sizeof(int));
+
+			free(job);
+
+			res = pthread_mutex_lock(&pool->mutex);
+			assert(res == 0);
+
+			if (written != sizeof(int)) {
+				pthreadpool_server_exit(pool);
+				pthread_mutex_unlock(&pool->mutex);
+				return NULL;
+			}
+		}
+
+		if ((pool->jobs == NULL) && (pool->shutdown != 0)) {
+			/*
+			 * No more work to do and we're asked to shut down, so
+			 * exit
+			 */
+			pthreadpool_server_exit(pool);
+
+			if (pool->num_threads == 0) {
+				/*
+				 * Ping the main thread waiting for all of us
+				 * workers to have quit.
+				 */
+				pthread_cond_broadcast(&pool->condvar);
+			}
+
+			pthread_mutex_unlock(&pool->mutex);
+			return NULL;
+		}
+	}
+}
+
+int pthreadpool_add_job(struct pthreadpool *pool, int job_id,
+			void (*fn)(void *private_data), void *private_data)
+{
+	struct pthreadpool_job *job;
+	pthread_t thread_id;
+	int res;
+	sigset_t mask, omask;
+
+	job = (struct pthreadpool_job *)malloc(sizeof(struct pthreadpool_job));
+	if (job == NULL) {
+		return ENOMEM;
+	}
+
+	job->fn = fn;
+	job->private_data = private_data;
+	job->id = job_id;
+	job->next = NULL;
+
+	res = pthread_mutex_lock(&pool->mutex);
+	if (res != 0) {
+		free(job);
+		return res;
+	}
+
+	if (pool->shutdown) {
+		/*
+		 * Protect against the pool being shut down while
+		 * trying to add a job
+		 */
+		res = pthread_mutex_unlock(&pool->mutex);
+		assert(res == 0);
+		free(job);
+		return EINVAL;
+	}
+
+	/*
+	 * Just some cleanup under the mutex
+	 */
+	pthreadpool_join_children(pool);
+
+	/*
+	 * Add job to the end of the queue
+	 */
+	if (pool->jobs == NULL) {
+		pool->jobs = job;
+	}
+	else {
+		pool->last_job->next = job;
+	}
+	pool->last_job = job;
+
+	if (pool->num_idle > 0) {
+		/*
+		 * We have idle threads, wake one.
+		 */
+		res = pthread_cond_signal(&pool->condvar);
+		pthread_mutex_unlock(&pool->mutex);
+		return res;
+	}
+
+	if (pool->num_threads >= pool->max_threads) {
+		/*
+		 * No more new threads, we just queue the request
+		 */
+		pthread_mutex_unlock(&pool->mutex);
+		return 0;
+	}
+
+	/*
+	 * Create a new worker thread. It should not receive any signals.
+	 */
+
+	sigfillset(&mask);
+
+        res = pthread_sigmask(SIG_BLOCK, &mask, &omask);
+	if (res != 0) {
+		pthread_mutex_unlock(&pool->mutex);
+		return res;
+	}
+
+	res = pthread_create(&thread_id, NULL, pthreadpool_server,
+				(void *)pool);
+	if (res == 0) {
+		pool->num_threads += 1;
+	}
+
+        assert(pthread_sigmask(SIG_SETMASK, &omask, NULL) == 0);
+
+	pthread_mutex_unlock(&pool->mutex);
+	return res;
+}
diff --git a/source3/lib/pthreadpool/pthreadpool.h b/source3/lib/pthreadpool/pthreadpool.h
new file mode 100644
index 0000000000..7ef7ddf419
--- /dev/null
+++ b/source3/lib/pthreadpool/pthreadpool.h
@@ -0,0 +1,42 @@
+/*
+ * Unix SMB/CIFS implementation.
+ * threadpool implementation based on pthreads
+ * Copyright (C) Volker Lendecke 2009
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __PTHREADPOOL_H__
+#define __PTHREADPOOL_H__
+
+struct pthreadpool;
+
+int pthreadpool_init(unsigned max_threads, struct pthreadpool **presult);
+int pthreadpool_destroy(struct pthreadpool *pool);
+
+/*
+ * Add a job to a pthreadpool.
+ */
+int pthreadpool_add_job(struct pthreadpool *pool, int job_id,
+			void (*fn)(void *private_data), void *private_data);
+
+/*
+ * Get the signalling fd out of a thread pool. This fd will become readable
+ * when a job is finished. The job that finished can be retrieved via
+ * pthreadpool_finished_job().
+ */
+int pthreadpool_sig_fd(struct pthreadpool *pool);
+int pthreadpool_finished_job(struct pthreadpool *pool);
+
+#endif
diff --git a/source3/lib/pthreadpool/tests.c b/source3/lib/pthreadpool/tests.c
new file mode 100644
index 0000000000..d365fbd5b6
--- /dev/null
+++ b/source3/lib/pthreadpool/tests.c
@@ -0,0 +1,362 @@
+#include <stdio.h>
+#include <string.h>
+#include <poll.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <unistd.h>
+#include "pthreadpool.h"
+
+static int test_init(void)
+{
+	struct pthreadpool *p;
+	int ret;
+
+	ret = pthreadpool_init(1, &p);
+	if (ret != 0) {
+		fprintf(stderr, "pthreadpool_init failed: %s\n",
+			strerror(ret));
+		return -1;
+	}
+	ret = pthreadpool_destroy(p);
+	if (ret != 0) {
+		fprintf(stderr, "pthreadpool_init failed: %s\n",
+			strerror(ret));
+		return -1;
+	}
+	return 0;
+}
+
+static void test_sleep(void *ptr)
+{
+	int *ptimeout = (int *)ptr;
+	int ret;
+	ret = poll(NULL, 0, *ptimeout);
+	if (ret != 0) {
+		fprintf(stderr, "poll returned %d (%s)\n",
+			ret, strerror(errno));
+	}
+}
+
+static int test_jobs(int num_threads, int num_jobs)
+{
+	char *finished;
+	struct pthreadpool *p;
+	int timeout = 1;
+	int i, ret;
+
+	finished = (char *)calloc(1, num_jobs);
+	if (finished == NULL) {
+		fprintf(stderr, "calloc failed\n");
+		return -1;
+	}
+
+	ret = pthreadpool_init(num_threads, &p);
+	if (ret != 0) {
+		fprintf(stderr, "pthreadpool_init failed: %s\n",
+			strerror(ret));
+		return -1;
+	}
+
+	for (i=0; i<num_jobs; i++) {
+		ret = pthreadpool_add_job(p, i, test_sleep, &timeout);
+		if (ret != 0) {
+			fprintf(stderr, "pthreadpool_add_job failed: %s\n",
+				strerror(ret));
+			return -1;
+		}
+	}
+
+	for (i=0; i<num_jobs; i++) {
+		ret = pthreadpool_finished_job(p);
+		if ((ret < 0) || (ret >= num_jobs)) {
+			fprintf(stderr, "invalid job number %d\n", ret);
+			return -1;
+		}
+		finished[ret] += 1;
+	}
+
+	for (i=0; i<num_jobs; i++) {
+		if (finished[i] != 1) {
+			fprintf(stderr, "finished[%d] = %d\n",
+				i, finished[i]);
+			return -1;
+		}
+	}
+
+	ret = pthreadpool_destroy(p);
+	if (ret != 0) {
+		fprintf(stderr, "pthreadpool_destroy failed: %s\n",
+			strerror(ret));
+		return -1;
+	}
+
+	free(finished);
+	return 0;
+}
+
+static int test_busydestroy(void)
+{
+	struct pthreadpool *p;
+	int timeout = 50;
+	struct pollfd pfd;
+	int ret;
+
+	ret = pthreadpool_init(1, &p);
+	if (ret != 0) {
+		fprintf(stderr, "pthreadpool_init failed: %s\n",
+			strerror(ret));
+		return -1;
+	}
+	ret = pthreadpool_add_job(p, 1, test_sleep, &timeout);
+	if (ret != 0) {
+		fprintf(stderr, "pthreadpool_add_job failed: %s\n",
+			strerror(ret));
+		return -1;
+	}
+	ret = pthreadpool_destroy(p);
+	if (ret != EBUSY) {
+		fprintf(stderr, "Could destroy a busy pool\n");
+		return -1;
+	}
+
+	pfd.fd = pthreadpool_sig_fd(p);
+	pfd.events = POLLIN|POLLERR;
+
+	poll(&pfd, 1, -1);
+
+	ret = pthreadpool_destroy(p);
+	if (ret != 0) {
+		fprintf(stderr, "pthreadpool_destroy failed: %s\n",
+			strerror(ret));
+		return -1;
+	}
+	return 0;
+}
+
+struct threaded_state {
+	pthread_t tid;
+	struct pthreadpool *p;
+	int start_job;
+	int num_jobs;
+	int timeout;
+};
+
+static void *test_threaded_worker(void *p)
+{
+	struct threaded_state *state = (struct threaded_state *)p;
+	int i;
+
+	for (i=0; i<state->num_jobs; i++) {
+		int ret = pthreadpool_add_job(state->p, state->start_job + i,
+					      test_sleep, &state->timeout);
+		if (ret != 0) {
+			fprintf(stderr, "pthreadpool_add_job failed: %s\n",
+				strerror(ret));
+			return NULL;
+		}
+	}
+	return NULL;
+}
+
+static int test_threaded_addjob(int num_pools, int num_threads, int poolsize,
+				int num_jobs)
+{
+	struct pthreadpool **pools;
+	struct threaded_state *states;
+	struct threaded_state *state;
+	struct pollfd *pfds;
+	char *finished;
+	pid_t child;
+	int i, ret, poolnum;
+	int received;
+
+	states = calloc(num_threads, sizeof(struct threaded_state));
+	if (states == NULL) {
+		fprintf(stderr, "calloc failed\n");
+		return -1;
+	}
+
+	finished = calloc(num_threads * num_jobs, 1);
+	if (finished == NULL) {
+		fprintf(stderr, "calloc failed\n");
+		return -1;
+	}
+
+	pools = calloc(num_pools, sizeof(struct pthreadpool *));
+	if (pools == NULL) {
+		fprintf(stderr, "calloc failed\n");
+		return -1;
+	}
+
+	pfds = calloc(num_pools, sizeof(struct pollfd));
+	if (pfds == NULL) {
+		fprintf(stderr, "calloc failed\n");
+		return -1;
+	}
+
+	for (i=0; i<num_pools; i++) {
+		ret = pthreadpool_init(poolsize, &pools[i]);
+		if (ret != 0) {
+			fprintf(stderr, "pthreadpool_init failed: %s\n",
+				strerror(ret));
+			return -1;
+		}
+		pfds[i].fd = pthreadpool_sig_fd(pools[i]);
+		pfds[i].events = POLLIN|POLLHUP;
+	}
+
+	poolnum = 0;
+
+	for (i=0; i<num_threads; i++) {
+		state = &states[i];
+
+		state->p = pools[poolnum];
+		poolnum = (poolnum + 1) % num_pools;
+
+		state->num_jobs = num_jobs;
+		state->timeout = 1;
+		state->start_job = i * num_jobs;
+
+		ret = pthread_create(&state->tid, NULL, test_threaded_worker,
+				     state);
+		if (ret != 0) {
+			fprintf(stderr, "pthread_create failed: %s\n",
+				strerror(ret));
+			return -1;
+		}
+	}
+
+	if (random() % 1) {
+		poll(NULL, 0, 1);
+	}
+
+	child = fork();
+	if (child < 0) {
+		fprintf(stderr, "fork failed: %s\n", strerror(errno));
+		return -1;
+	}
+	if (child == 0) {
+		for (i=0; i<num_pools; i++) {
+			ret = pthreadpool_destroy(pools[i]);
+			if (ret != 0) {
+				fprintf(stderr, "pthreadpool_destroy failed: "
+					"%s\n", strerror(ret));
+				exit(1);
+			}
+		}
+		/* child */
+		exit(0);
+	}
+
+	for (i=0; i<num_threads; i++) {
+		ret = pthread_join(states[i].tid, NULL);
+		if (ret != 0) {
+			fprintf(stderr, "pthread_join(%d) failed: %s\n",
+				i, strerror(ret));
+			return -1;
+		}
+	}
+
+	received = 0;
+
+	while (received < num_threads*num_jobs) {
+		int j;
+
+		ret = poll(pfds, num_pools, 1000);
+		if (ret == -1) {
+			fprintf(stderr, "poll failed: %s\n",
+				strerror(errno));
+			return -1;
+		}
+		if (ret == 0) {
+			fprintf(stderr, "\npoll timed out\n");
+			break;
+		}
+
+		for (j=0; j<num_pools; j++) {
+
+			if ((pfds[j].revents & (POLLIN|POLLHUP)) == 0) {
+				continue;
+			}
+
+			ret = pthreadpool_finished_job(pools[j]);
+			if ((ret < 0) || (ret >= num_jobs * num_threads)) {
+				fprintf(stderr, "invalid job number %d\n",
+					ret);
+				return -1;
+			}
+			finished[ret] += 1;
+			received += 1;
+		}
+	}
+
+	for (i=0; i<num_threads*num_jobs; i++) {
+		if (finished[i] != 1) {
+			fprintf(stderr, "finished[%d] = %d\n",
+				i, finished[i]);
+			return -1;
+		}
+	}
+
+	for (i=0; i<num_pools; i++) {
+		ret = pthreadpool_destroy(pools[i]);
+		if (ret != 0) {
+			fprintf(stderr, "pthreadpool_destroy failed: %s\n",
+				strerror(ret));
+			return -1;
+		}
+	}
+
+	free(pfds);
+	free(pools);
+	free(states);
+	free(finished);
+
+	return 0;
+}
+
+int main(void)
+{
+	int ret;
+
+	ret = test_init();
+	if (ret != 0) {
+		fprintf(stderr, "test_init failed\n");
+		return 1;
+	}
+
+	ret = test_jobs(10, 10000);
+	if (ret != 0) {
+		fprintf(stderr, "test_jobs failed\n");
+		return 1;
+	}
+
+	ret = test_busydestroy();
+	if (ret != 0) {
+		fprintf(stderr, "test_busydestroy failed\n");
+		return 1;
+	}
+
+	/*
+	 * Test 10 threads adding jobs on a single pool
+	 */
+	ret = test_threaded_addjob(1, 10, 5, 5000);
+	if (ret != 0) {
+		fprintf(stderr, "test_jobs failed\n");
+		return 1;
+	}
+
+	/*
+	 * Test 10 threads on 3 pools to verify our fork handling
+	 * works right.
+	 */
+	ret = test_threaded_addjob(3, 10, 5, 5000);
+	if (ret != 0) {
+		fprintf(stderr, "test_jobs failed\n");
+		return 1;
+	}
+
+	printf("success\n");
+	return 0;
+}
-- 
cgit