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-rw-r--r--xlators/features/changelog/src/changelog-notifier.c314
1 files changed, 314 insertions, 0 deletions
diff --git a/xlators/features/changelog/src/changelog-notifier.c b/xlators/features/changelog/src/changelog-notifier.c
new file mode 100644
index 00000000..1f8b3125
--- /dev/null
+++ b/xlators/features/changelog/src/changelog-notifier.c
@@ -0,0 +1,314 @@
+/*
+ Copyright (c) 2013 Red Hat, Inc. <http://www.redhat.com>
+ This file is part of GlusterFS.
+
+ This file is licensed to you under your choice of the GNU Lesser
+ General Public License, version 3 or any later version (LGPLv3 or
+ later), or the GNU General Public License, version 2 (GPLv2), in all
+ cases as published by the Free Software Foundation.
+*/
+
+#include "changelog-notifier.h"
+
+#include <pthread.h>
+
+inline static void
+changelog_notify_clear_fd (changelog_notify_t *cn, int i)
+{
+ cn->client_fd[i] = -1;
+}
+
+inline static void
+changelog_notify_save_fd (changelog_notify_t *cn, int i, int fd)
+{
+ cn->client_fd[i] = fd;
+}
+
+static int
+changelog_notify_insert_fd (xlator_t *this, changelog_notify_t *cn, int fd)
+{
+ int i = 0;
+ int ret = 0;
+
+ for (; i < CHANGELOG_MAX_CLIENTS; i++) {
+ if (cn->client_fd[i] == -1)
+ break;
+ }
+
+ if (i == CHANGELOG_MAX_CLIENTS) {
+ /**
+ * this case should not be hit as listen() would limit
+ * the number of completely established connections.
+ */
+ gf_log (this->name, GF_LOG_WARNING,
+ "hit max client limit (%d)", CHANGELOG_MAX_CLIENTS);
+ ret = -1;
+ }
+ else
+ changelog_notify_save_fd (cn, i, fd);
+
+ return ret;
+}
+
+static void
+changelog_notify_fill_rset (changelog_notify_t *cn, fd_set *rset, int *maxfd)
+{
+ int i = 0;
+
+ FD_ZERO (rset);
+
+ FD_SET (cn->socket_fd, rset);
+ *maxfd = cn->socket_fd;
+
+ FD_SET (cn->rfd, rset);
+ *maxfd = max (*maxfd, cn->rfd);
+
+ for (; i < CHANGELOG_MAX_CLIENTS; i++) {
+ if (cn->client_fd[i] != -1) {
+ FD_SET (cn->client_fd[i], rset);
+ *maxfd = max (*maxfd, cn->client_fd[i]);
+ }
+ }
+
+ *maxfd = *maxfd + 1;
+}
+
+static int
+changelog_notify_client (changelog_notify_t *cn, char *path, ssize_t len)
+{
+ int i = 0;
+ int ret = 0;
+
+ for (; i < CHANGELOG_MAX_CLIENTS; i++) {
+ if (cn->client_fd[i] == -1)
+ continue;
+
+ if (changelog_write (cn->client_fd[i],
+ path, len)) {
+ ret = -1;
+
+ close (cn->client_fd[i]);
+ changelog_notify_clear_fd (cn, i);
+ }
+ }
+
+ return ret;
+}
+
+static void
+changelog_notifier_init (changelog_notify_t *cn)
+{
+ int i = 0;
+
+ cn->socket_fd = -1;
+
+ for (; i < CHANGELOG_MAX_CLIENTS; i++) {
+ changelog_notify_clear_fd (cn, i);
+ }
+}
+
+static void
+changelog_close_client_conn (changelog_notify_t *cn)
+{
+ int i = 0;
+
+ for (; i < CHANGELOG_MAX_CLIENTS; i++) {
+ if (cn->client_fd[i] == -1)
+ continue;
+
+ close (cn->client_fd[i]);
+ changelog_notify_clear_fd (cn, i);
+ }
+}
+
+static void
+changelog_notifier_cleanup (void *arg)
+{
+ changelog_notify_t *cn = NULL;
+
+ cn = (changelog_notify_t *) arg;
+
+ changelog_close_client_conn (cn);
+
+ if (cn->socket_fd != -1)
+ close (cn->socket_fd);
+
+ if (cn->rfd)
+ close (cn->rfd);
+
+ if (unlink (cn->sockpath))
+ gf_log ("", GF_LOG_WARNING,
+ "could not unlink changelog socket file"
+ " %s (reason: %s", cn->sockpath, strerror (errno));
+}
+
+void *
+changelog_notifier (void *data)
+{
+ int i = 0;
+ int fd = 0;
+ int max_fd = 0;
+ int len = 0;
+ ssize_t readlen = 0;
+ xlator_t *this = NULL;
+ changelog_priv_t *priv = NULL;
+ changelog_notify_t *cn = NULL;
+ struct sockaddr_un local = {0,};
+ char path[PATH_MAX] = {0,};
+ char abspath[PATH_MAX] = {0,};
+
+ char buffer;
+ fd_set rset;
+
+ priv = (changelog_priv_t *) data;
+
+ cn = &priv->cn;
+ this = cn->this;
+
+ pthread_cleanup_push (changelog_notifier_cleanup, cn);
+
+ changelog_notifier_init (cn);
+
+ cn->socket_fd = socket (AF_UNIX, SOCK_STREAM, 0);
+ if (cn->socket_fd < 0) {
+ gf_log (this->name, GF_LOG_ERROR,
+ "changelog socket error (reason: %s)",
+ strerror (errno));
+ goto out;
+ }
+
+ CHANGELOG_MAKE_SOCKET_PATH (priv->changelog_brick,
+ cn->sockpath, PATH_MAX);
+ if (unlink (cn->sockpath) < 0) {
+ if (errno != ENOENT) {
+ gf_log (this->name, GF_LOG_ERROR,
+ "Could not unlink changelog socket file (%s)"
+ " (reason: %s)",
+ CHANGELOG_UNIX_SOCK, strerror (errno));
+ goto cleanup;
+ }
+ }
+
+ local.sun_family = AF_UNIX;
+ strcpy (local.sun_path, cn->sockpath);
+
+ len = strlen (local.sun_path) + sizeof (local.sun_family);
+
+ /* bind to the unix domain socket */
+ if (bind (cn->socket_fd, (struct sockaddr *) &local, len) < 0) {
+ gf_log (this->name, GF_LOG_ERROR,
+ "Could not bind to changelog socket (reason: %s)",
+ strerror (errno));
+ goto cleanup;
+ }
+
+ /* listen for incoming connections */
+ if (listen (cn->socket_fd, CHANGELOG_MAX_CLIENTS) < 0) {
+ gf_log (this->name, GF_LOG_ERROR,
+ "listen() error on changelog socket (reason: %s)",
+ strerror (errno));
+ goto cleanup;
+ }
+
+ /**
+ * simple select() on all to-be-read file descriptors. This method
+ * though old school works pretty well when you have a handfull of
+ * fd's to be watched (clients).
+ *
+ * Future TODO: move this to epoll based notification facility if
+ * number of clients increase.
+ */
+ for (;;) {
+ changelog_notify_fill_rset (cn, &rset, &max_fd);
+
+ if (select (max_fd, &rset, NULL, NULL, NULL) < 0) {
+ gf_log (this->name, GF_LOG_ERROR,
+ "select() returned -1 (reason: %s)",
+ strerror (errno));
+ sleep (2);
+ continue;
+ }
+
+ if (FD_ISSET (cn->socket_fd, &rset)) {
+ fd = accept (cn->socket_fd, NULL, NULL);
+ if (fd < 0) {
+ gf_log (this->name, GF_LOG_ERROR,
+ "accept error on changelog socket"
+ " (reason: %s)", strerror (errno));
+ } else if (changelog_notify_insert_fd (this, cn, fd)) {
+ gf_log (this->name, GF_LOG_ERROR,
+ "hit max client limit");
+ }
+ }
+
+ if (FD_ISSET (cn->rfd, &rset)) {
+ /**
+ * read changelog filename and notify all connected
+ * clients.
+ */
+ readlen = 0;
+ while (readlen < PATH_MAX) {
+ len = read (cn->rfd, &path[readlen++], 1);
+ if (len == -1) {
+ break;
+ }
+
+ if (len == 0) {
+ gf_log (this->name, GF_LOG_ERROR,
+ "rollover thread sent EOF"
+ " on pipe - possibly a crash.");
+ /* be blunt and close all connections */
+ pthread_exit(NULL);
+ }
+
+ if (path[readlen - 1] == '\0')
+ break;
+ }
+
+ /* should we close all client connections here too? */
+ if (len < 0 || readlen == PATH_MAX) {
+ gf_log (this->name, GF_LOG_ERROR,
+ "Could not get pathname from rollover"
+ " thread or pathname too long");
+ goto process_rest;
+ }
+
+ (void) snprintf (abspath, PATH_MAX,
+ "%s/%s", priv->changelog_dir, path);
+ if (changelog_notify_client (cn, abspath,
+ strlen (abspath) + 1))
+ gf_log (this->name, GF_LOG_ERROR,
+ "could not notify some clients with new"
+ " changelogs");
+ }
+
+ process_rest:
+ for (i = 0; i < CHANGELOG_MAX_CLIENTS; i++) {
+ if ( (fd = cn->client_fd[i]) == -1 )
+ continue;
+
+ if (FD_ISSET (fd, &rset)) {
+ /**
+ * the only data we accept from the client is a
+ * disconnect. Anything else is treated as bogus
+ * and is silently discarded (also warned!!!).
+ */
+ if ( (readlen = read (fd, &buffer, 1)) <= 0 ) {
+ close (fd);
+ changelog_notify_clear_fd (cn, i);
+ } else {
+ /* silently discard data and log */
+ gf_log (this->name, GF_LOG_WARNING,
+ "misbehaving changelog client");
+ }
+ }
+ }
+
+ }
+
+ cleanup:;
+ pthread_cleanup_pop (1);
+
+ out:
+ return NULL;
+}