Adding upstream version 2:4.20.0+dfsg.upstream/2%4.20.0+dfsg

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 382 insertions, 0 deletions

diff --git a/ctdb/server/ctdb_cluster_mutex.c b/ctdb/server/ctdb_cluster_mutex.c
new file mode 100644
index 0000000..2fbe301
--- /dev/null
+++ b/ctdb/server/ctdb_cluster_mutex.c
@@ -0,0 +1,382 @@
+/*
+   CTDB cluster mutex handling
+
+   Copyright (C) Andrew Tridgell  2007
+   Copyright (C) Ronnie Sahlberg  2007
+   Copyright (C) Martin Schwenke  2016
+
+   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 "replace.h"
+#include "system/network.h"
+#include "system/filesys.h"
+
+#include <tevent.h>
+
+#include "lib/util/debug.h"
+#include "lib/util/time.h"
+#include "lib/util/strv.h"
+#include "lib/util/strv_util.h"
+#include "lib/util/sys_rw.h"
+#include "lib/util/blocking.h"
+
+#include "ctdb_private.h"
+
+#include "ctdb_cluster_mutex.h"
+
+struct ctdb_cluster_mutex_handle {
+	struct ctdb_context *ctdb;
+	cluster_mutex_handler_t handler;
+	void *private_data;
+	cluster_mutex_lost_handler_t lost_handler;
+	void *lost_data;
+	int fd[2];
+	struct tevent_timer *te;
+	struct tevent_fd *fde;
+	pid_t child;
+	struct timeval start_time;
+	bool have_response;
+};
+
+static void cluster_mutex_timeout(struct tevent_context *ev,
+				  struct tevent_timer *te,
+				  struct timeval t, void *private_data)
+{
+	struct ctdb_cluster_mutex_handle *h =
+		talloc_get_type(private_data, struct ctdb_cluster_mutex_handle);
+	double latency = timeval_elapsed(&h->start_time);
+
+	if (h->handler != NULL) {
+		h->handler('2', latency, h->private_data);
+	}
+}
+
+
+/* When the handle is freed it causes any child holding the mutex to
+ * be killed, thus freeing the mutex */
+static int cluster_mutex_destructor(struct ctdb_cluster_mutex_handle *h)
+{
+	if (h->fd[0] != -1) {
+		h->fd[0] = -1;
+	}
+	ctdb_kill(h->ctdb, h->child, SIGTERM);
+	return 0;
+}
+
+/* this is called when the client process has completed ctdb_recovery_lock()
+   and has written data back to us through the pipe.
+*/
+static void cluster_mutex_handler(struct tevent_context *ev,
+				  struct tevent_fd *fde,
+				  uint16_t flags, void *private_data)
+{
+	struct ctdb_cluster_mutex_handle *h=
+		talloc_get_type(private_data, struct ctdb_cluster_mutex_handle);
+	double latency = timeval_elapsed(&h->start_time);
+	char c = '0';
+	int ret;
+
+	/* Got response from child process so abort timeout */
+	TALLOC_FREE(h->te);
+
+	ret = sys_read(h->fd[0], &c, 1);
+
+	/* Don't call the handler more than once.  It only exists to
+	 * process the initial response from the helper. */
+	if (h->have_response) {
+		/* Only deal with EOF due to process exit.  Silently
+		 * ignore any other output. */
+		if (ret == 0) {
+			if (h->lost_handler != NULL) {
+				h->lost_handler(h->lost_data);
+			}
+		}
+		return;
+	}
+	h->have_response = true;
+
+	/* If the child wrote status then just pass it to the handler.
+	 * If no status was written then this is an unexpected error
+	 * so pass generic error code to handler. */
+	if (h->handler != NULL) {
+		h->handler(ret == 1 ? c : '3', latency, h->private_data);
+	}
+}
+
+static char cluster_mutex_helper[PATH_MAX+1] = "";
+
+static bool cluster_mutex_helper_args_file(TALLOC_CTX *mem_ctx,
+					   const char *argstring,
+					   char ***argv)
+{
+	struct stat st;
+	size_t size = sizeof(cluster_mutex_helper);
+	const char *t;
+	char **args = NULL;
+	int ret;
+
+	if (cluster_mutex_helper[0] != '\0') {
+		goto helper_done;
+	}
+
+	t = getenv("CTDB_CLUSTER_MUTEX_HELPER");
+	if (t != NULL) {
+		size_t len;
+
+		len = strlcpy(cluster_mutex_helper, t, size);
+		if (len >= size) {
+			DBG_ERR("error: CTDB_CLUSTER_MUTEX_HELPER too long\n");
+			exit(1);
+		}
+	} else {
+		ret = snprintf(cluster_mutex_helper,
+			       size,
+			       "%s/%s",
+			       CTDB_HELPER_BINDIR,
+			       "ctdb_mutex_fcntl_helper");
+		if (ret < 0 || (size_t)ret >= size) {
+			D_ERR("Unable to set cluster mutex helper - "
+			      "path too long\n");
+			exit(1);
+		}
+	}
+
+	ret = stat(cluster_mutex_helper, &st);
+	if (ret != 0) {
+		D_ERR("Unable to set cluster mutex helper \"%s\" - %s\n",
+		      cluster_mutex_helper,
+		      strerror(errno));
+		exit(1);
+	}
+
+	if ((st.st_mode & S_IXUSR) == 0) {
+		D_ERR("Unable to set cluster_mutex helper \"%s\" - "
+		      "not executable\n",
+		      cluster_mutex_helper);
+		exit(1);
+	}
+
+	D_NOTICE("Set cluster mutex helper to \"%s\"\n", cluster_mutex_helper);
+
+helper_done:
+
+	/* Array includes default helper, file and NULL */
+	args = talloc_array(mem_ctx, char *, 3);
+	if (args == NULL) {
+		DBG_ERR("Memory allocation error\n");
+		return false;
+	}
+
+	args[0] = cluster_mutex_helper;
+
+	args[1] = talloc_strdup(args, argstring);
+	if (args[1] == NULL) {
+		DBG_ERR("Memory allocation error\n");
+		return false;
+	}
+
+	args[2] = NULL;
+
+	*argv = args;
+	return true;
+}
+
+static bool cluster_mutex_helper_args_cmd(TALLOC_CTX *mem_ctx,
+					  const char *argstring,
+					  char ***argv)
+{
+	int i, ret, n;
+	char **args = NULL;
+	char *strv = NULL;
+	char *t = NULL;
+
+	ret = strv_split(mem_ctx, &strv, argstring, " \t");
+	if (ret != 0) {
+		D_ERR("Unable to parse mutex helper command \"%s\" (%s)\n",
+		      argstring,
+		      strerror(ret));
+		return false;
+	}
+	n = strv_count(strv);
+	if (n == 0) {
+		D_ERR("Mutex helper command is empty \"%s\"\n", argstring);
+		return false;
+	}
+
+	/* Extra slot for NULL */
+	args = talloc_array(mem_ctx, char *, n + 1);
+	if (args == NULL) {
+		DBG_ERR("Memory allocation error\n");
+		return false;
+	}
+
+	talloc_steal(args, strv);
+
+	t = NULL;
+	for (i = 0 ; i < n; i++) {
+		t = strv_next(strv, t);
+		args[i] = t;
+	}
+
+	args[n] = NULL;
+
+	*argv = args;
+	return true;
+}
+
+static bool cluster_mutex_helper_args(TALLOC_CTX *mem_ctx,
+				      const char *argstring,
+				      char ***argv)
+{
+	bool ok;
+
+	if (argstring != NULL && argstring[0] == '!') {
+		ok = cluster_mutex_helper_args_cmd(mem_ctx, &argstring[1], argv);
+	} else {
+		ok = cluster_mutex_helper_args_file(mem_ctx, argstring, argv);
+	}
+
+	return ok;
+}
+
+struct ctdb_cluster_mutex_handle *
+ctdb_cluster_mutex(TALLOC_CTX *mem_ctx,
+		   struct ctdb_context *ctdb,
+		   const char *argstring,
+		   int timeout,
+		   cluster_mutex_handler_t handler,
+		   void *private_data,
+		   cluster_mutex_lost_handler_t lost_handler,
+		   void *lost_data)
+{
+	struct ctdb_cluster_mutex_handle *h;
+	char **args;
+	sigset_t sigset_term;
+	int ret;
+
+	h = talloc(mem_ctx, struct ctdb_cluster_mutex_handle);
+	if (h == NULL) {
+		DBG_ERR("out of memory\n");
+		return NULL;
+	}
+
+	h->start_time = timeval_current();
+	h->fd[0] = -1;
+	h->fd[1] = -1;
+	h->have_response = false;
+
+	ret = pipe(h->fd);
+	if (ret != 0) {
+		talloc_free(h);
+		DBG_ERR("Failed to open pipe\n");
+		return NULL;
+	}
+	set_close_on_exec(h->fd[0]);
+
+	/* Create arguments for lock helper */
+	if (!cluster_mutex_helper_args(h, argstring, &args)) {
+		close(h->fd[0]);
+		close(h->fd[1]);
+		talloc_free(h);
+		return NULL;
+	}
+
+	sigemptyset(&sigset_term);
+	sigaddset(&sigset_term, SIGTERM);
+	ret = sigprocmask(SIG_BLOCK, &sigset_term, NULL);
+	if (ret != 0) {
+		DBG_WARNING("Failed to block SIGTERM (%d)\n", errno);
+	}
+
+	h->child = ctdb_fork(ctdb);
+	if (h->child == (pid_t)-1) {
+		close(h->fd[0]);
+		close(h->fd[1]);
+		talloc_free(h);
+		ret = sigprocmask(SIG_UNBLOCK, &sigset_term, NULL);
+		if (ret != 0) {
+			DBG_WARNING("Failed to unblock SIGTERM (%d)\n", errno);
+		}
+		return NULL;
+	}
+
+	if (h->child == 0) {
+		struct sigaction sa = {
+			.sa_handler = SIG_DFL,
+		};
+
+		ret = sigaction(SIGTERM, &sa, NULL);
+		if (ret != 0) {
+			DBG_WARNING("Failed to reset signal handler (%d)\n",
+				    errno);
+		}
+
+		ret = sigprocmask(SIG_UNBLOCK, &sigset_term, NULL);
+		if (ret != 0) {
+			DBG_WARNING("Failed to unblock SIGTERM (%d)\n", errno);
+		}
+
+		/* Make stdout point to the pipe */
+		close(STDOUT_FILENO);
+		dup2(h->fd[1], STDOUT_FILENO);
+		close(h->fd[1]);
+
+		execv(args[0], args);
+
+		/* Only happens on error */
+		DBG_ERR("execv() failed\n");
+		_exit(1);
+	}
+
+	/* Parent */
+
+	ret = sigprocmask(SIG_UNBLOCK, &sigset_term, NULL);
+	if (ret != 0) {
+		DBG_WARNING("Failed to unblock SIGTERM (%d)\n", errno);
+	}
+
+	DBG_DEBUG("Created PIPE FD:%d\n", h->fd[0]);
+	set_close_on_exec(h->fd[0]);
+
+	close(h->fd[1]);
+	h->fd[1] = -1;
+
+	talloc_set_destructor(h, cluster_mutex_destructor);
+
+	if (timeout != 0) {
+		h->te = tevent_add_timer(ctdb->ev, h,
+					 timeval_current_ofs(timeout, 0),
+					 cluster_mutex_timeout, h);
+	} else {
+		h->te = NULL;
+	}
+
+	h->fde = tevent_add_fd(ctdb->ev, h, h->fd[0], TEVENT_FD_READ,
+			       cluster_mutex_handler, (void *)h);
+
+	if (h->fde == NULL) {
+		talloc_free(h);
+		return NULL;
+	}
+	tevent_fd_set_auto_close(h->fde);
+
+	h->ctdb = ctdb;
+	h->handler = handler;
+	h->private_data = private_data;
+	h->lost_handler = lost_handler;
+	h->lost_data = lost_data;
+
+	return h;
+}