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path: root/source4/cluster/ctdb/common/ctdb_io.c
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Diffstat (limited to 'source4/cluster/ctdb/common/ctdb_io.c')
-rw-r--r--source4/cluster/ctdb/common/ctdb_io.c338
1 files changed, 338 insertions, 0 deletions
diff --git a/source4/cluster/ctdb/common/ctdb_io.c b/source4/cluster/ctdb/common/ctdb_io.c
new file mode 100644
index 0000000000..ca9c635878
--- /dev/null
+++ b/source4/cluster/ctdb/common/ctdb_io.c
@@ -0,0 +1,338 @@
+/*
+ ctdb database library
+ Utility functions to read/write blobs of data from a file descriptor
+ and handle the case where we might need multiple read/writes to get all the
+ data.
+
+ Copyright (C) Andrew Tridgell 2006
+
+ 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 "includes.h"
+#include "lib/tdb/include/tdb.h"
+#include "lib/events/events.h"
+#include "lib/util/dlinklist.h"
+#include "system/network.h"
+#include "system/filesys.h"
+#include "../include/ctdb_private.h"
+#include "../include/ctdb.h"
+
+/* structures for packet queueing - see common/ctdb_io.c */
+struct ctdb_partial {
+ uint8_t *data;
+ uint32_t length;
+};
+
+struct ctdb_queue_pkt {
+ struct ctdb_queue_pkt *next, *prev;
+ uint8_t *data;
+ uint32_t length;
+ uint32_t full_length;
+};
+
+struct ctdb_queue {
+ struct ctdb_context *ctdb;
+ struct ctdb_partial partial; /* partial input packet */
+ struct ctdb_queue_pkt *out_queue;
+ struct fd_event *fde;
+ int fd;
+ size_t alignment;
+ void *private_data;
+ ctdb_queue_cb_fn_t callback;
+};
+
+
+
+/*
+ called when an incoming connection is readable
+*/
+static void queue_io_read(struct ctdb_queue *queue)
+{
+ int num_ready = 0;
+ ssize_t nread;
+ uint8_t *data, *data_base;
+
+ if (ioctl(queue->fd, FIONREAD, &num_ready) != 0) {
+ return;
+ }
+ if (num_ready == 0) {
+ /* the descriptor has been closed */
+ goto failed;
+ }
+
+
+ queue->partial.data = talloc_realloc(queue, queue->partial.data,
+ uint8_t,
+ num_ready + queue->partial.length);
+
+ if (queue->partial.data == NULL) {
+ DEBUG(0,("read error alloc failed for %u\n",
+ num_ready + queue->partial.length));
+ goto failed;
+ }
+
+ nread = read(queue->fd, queue->partial.data + queue->partial.length, num_ready);
+ if (nread <= 0) {
+ DEBUG(0,("read error nread=%d\n", (int)nread));
+ goto failed;
+ }
+
+
+ data = queue->partial.data;
+ nread += queue->partial.length;
+
+ queue->partial.data = NULL;
+ queue->partial.length = 0;
+
+ if (nread >= 4 && *(uint32_t *)data == nread) {
+ /* it is the responsibility of the incoming packet
+ function to free 'data' */
+ queue->callback(data, nread, queue->private_data);
+ return;
+ }
+
+ data_base = data;
+
+ while (nread >= 4 && *(uint32_t *)data <= nread) {
+ /* we have at least one packet */
+ uint8_t *d2;
+ uint32_t len;
+ len = *(uint32_t *)data;
+ if (len == 0) {
+ /* bad packet! treat as EOF */
+ DEBUG(0,("Invalid packet of length 0\n"));
+ goto failed;
+ }
+ d2 = (uint8_t *)talloc_memdup(queue, data, len);
+ if (d2 == NULL) {
+ DEBUG(0,("read error memdup failed for %u\n", len));
+ /* sigh */
+ goto failed;
+ }
+ queue->callback(d2, len, queue->private_data);
+ data += len;
+ nread -= len;
+ }
+
+ if (nread > 0) {
+ /* we have only part of a packet */
+ if (data_base == data) {
+ queue->partial.data = data;
+ queue->partial.length = nread;
+ } else {
+ queue->partial.data = (uint8_t *)talloc_memdup(queue, data, nread);
+ if (queue->partial.data == NULL) {
+ DEBUG(0,("read error memdup partial failed for %u\n",
+ (unsigned)nread));
+ goto failed;
+ }
+ queue->partial.length = nread;
+ talloc_free(data_base);
+ }
+ return;
+ }
+
+ talloc_free(data_base);
+ return;
+
+failed:
+ queue->callback(NULL, 0, queue->private_data);
+}
+
+
+/* used when an event triggers a dead queue */
+static void queue_dead(struct event_context *ev, struct timed_event *te,
+ struct timeval t, void *private_data)
+{
+ struct ctdb_queue *queue = talloc_get_type(private_data, struct ctdb_queue);
+ queue->callback(NULL, 0, queue->private_data);
+}
+
+
+/*
+ called when an incoming connection is writeable
+*/
+static void queue_io_write(struct ctdb_queue *queue)
+{
+ while (queue->out_queue) {
+ struct ctdb_queue_pkt *pkt = queue->out_queue;
+ ssize_t n;
+ if (queue->ctdb->flags & CTDB_FLAG_TORTURE) {
+ n = write(queue->fd, pkt->data, 1);
+ } else {
+ n = write(queue->fd, pkt->data, pkt->length);
+ }
+
+ if (n == -1 && errno != EAGAIN && errno != EWOULDBLOCK) {
+ if (pkt->length != pkt->full_length) {
+ /* partial packet sent - we have to drop it */
+ DLIST_REMOVE(queue->out_queue, pkt);
+ talloc_free(pkt);
+ }
+ talloc_free(queue->fde);
+ queue->fde = NULL;
+ queue->fd = -1;
+ event_add_timed(queue->ctdb->ev, queue, timeval_zero(),
+ queue_dead, queue);
+ return;
+ }
+ if (n <= 0) return;
+
+ if (n != pkt->length) {
+ pkt->length -= n;
+ pkt->data += n;
+ return;
+ }
+
+ DLIST_REMOVE(queue->out_queue, pkt);
+ talloc_free(pkt);
+ }
+
+ EVENT_FD_NOT_WRITEABLE(queue->fde);
+}
+
+/*
+ called when an incoming connection is readable or writeable
+*/
+static void queue_io_handler(struct event_context *ev, struct fd_event *fde,
+ uint16_t flags, void *private_data)
+{
+ struct ctdb_queue *queue = talloc_get_type(private_data, struct ctdb_queue);
+
+ if (flags & EVENT_FD_READ) {
+ queue_io_read(queue);
+ } else {
+ queue_io_write(queue);
+ }
+}
+
+
+/*
+ queue a packet for sending
+*/
+int ctdb_queue_send(struct ctdb_queue *queue, uint8_t *data, uint32_t length)
+{
+ struct ctdb_queue_pkt *pkt;
+ uint32_t length2, full_length;
+
+ if (queue->alignment) {
+ /* enforce the length and alignment rules from the tcp packet allocator */
+ length2 = (length+(queue->alignment-1)) & ~(queue->alignment-1);
+ *(uint32_t *)data = length2;
+ } else {
+ length2 = length;
+ }
+
+ if (length2 != length) {
+ memset(data+length, 0, length2-length);
+ }
+
+ full_length = length2;
+
+ /* if the queue is empty then try an immediate write, avoiding
+ queue overhead. This relies on non-blocking sockets */
+ if (queue->out_queue == NULL && queue->fd != -1 &&
+ !(queue->ctdb->flags & CTDB_FLAG_TORTURE)) {
+ ssize_t n = write(queue->fd, data, length2);
+ if (n == -1 && errno != EAGAIN && errno != EWOULDBLOCK) {
+ talloc_free(queue->fde);
+ queue->fde = NULL;
+ queue->fd = -1;
+ event_add_timed(queue->ctdb->ev, queue, timeval_zero(),
+ queue_dead, queue);
+ /* yes, we report success, as the dead node is
+ handled via a separate event */
+ return 0;
+ }
+ if (n > 0) {
+ data += n;
+ length2 -= n;
+ }
+ if (length2 == 0) return 0;
+ }
+
+ pkt = talloc(queue, struct ctdb_queue_pkt);
+ CTDB_NO_MEMORY(queue->ctdb, pkt);
+
+ pkt->data = (uint8_t *)talloc_memdup(pkt, data, length2);
+ CTDB_NO_MEMORY(queue->ctdb, pkt->data);
+
+ pkt->length = length2;
+ pkt->full_length = full_length;
+
+ if (queue->out_queue == NULL && queue->fd != -1) {
+ EVENT_FD_WRITEABLE(queue->fde);
+ }
+
+ DLIST_ADD_END(queue->out_queue, pkt, struct ctdb_queue_pkt *);
+
+ return 0;
+}
+
+
+/*
+ setup the fd used by the queue
+ */
+int ctdb_queue_set_fd(struct ctdb_queue *queue, int fd)
+{
+ queue->fd = fd;
+ talloc_free(queue->fde);
+ queue->fde = NULL;
+
+ if (fd != -1) {
+ queue->fde = event_add_fd(queue->ctdb->ev, queue, fd, EVENT_FD_READ|EVENT_FD_AUTOCLOSE,
+ queue_io_handler, queue);
+ if (queue->fde == NULL) {
+ return -1;
+ }
+
+ if (queue->out_queue) {
+ EVENT_FD_WRITEABLE(queue->fde);
+ }
+ }
+
+ return 0;
+}
+
+
+
+/*
+ setup a packet queue on a socket
+ */
+struct ctdb_queue *ctdb_queue_setup(struct ctdb_context *ctdb,
+ TALLOC_CTX *mem_ctx, int fd, int alignment,
+
+ ctdb_queue_cb_fn_t callback,
+ void *private_data)
+{
+ struct ctdb_queue *queue;
+
+ queue = talloc_zero(mem_ctx, struct ctdb_queue);
+ CTDB_NO_MEMORY_NULL(ctdb, queue);
+
+ queue->ctdb = ctdb;
+ queue->fd = fd;
+ queue->alignment = alignment;
+ queue->private_data = private_data;
+ queue->callback = callback;
+ if (fd != -1) {
+ if (ctdb_queue_set_fd(queue, fd) != 0) {
+ talloc_free(queue);
+ return NULL;
+ }
+ }
+
+ return queue;
+}
generated by cgit (git 2.34.1) at 2025-04-01 12:35:29 +0000