--- /dev/null
+/*
+ * Unix SMB/CIFS implementation.
+ * Samba internal messaging functions
+ * Copyright (C) 2013 by Volker Lendecke
+ *
+ * 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/util/data_blob.h"
+#include "lib/util/debug.h"
+#include "lib/unix_msg/unix_msg.h"
+#include "system/filesys.h"
+#include "messages.h"
+#include "lib/param/param.h"
+#include "poll_funcs/poll_funcs_tevent.h"
+#include "unix_msg/unix_msg.h"
+#include "librpc/gen_ndr/messaging.h"
+
+struct messaging_dgm_context {
+ struct messaging_context *msg_ctx;
+ struct poll_funcs msg_callbacks;
+ struct unix_msg_ctx *dgm_ctx;
+ char *cache_dir;
+ int lockfile_fd;
+};
+
+struct messaging_dgm_hdr {
+ uint32_t msg_version;
+ enum messaging_type msg_type;
+ struct server_id dst;
+ struct server_id src;
+};
+
+static NTSTATUS messaging_dgm_send(struct messaging_context *msg_ctx,
+ struct server_id pid, int msg_type,
+ const DATA_BLOB *data,
+ struct messaging_backend *backend);
+static void messaging_dgm_recv(struct unix_msg_ctx *ctx,
+ uint8_t *msg, size_t msg_len,
+ void *private_data);
+
+static int messaging_dgm_context_destructor(struct messaging_dgm_context *c);
+
+static int messaging_dgm_lockfile_create(const char *cache_dir, pid_t pid,
+ int *plockfile_fd, uint64_t unique)
+{
+ char buf[PATH_MAX];
+ char *dir, *to_free;
+ ssize_t dirlen;
+ char *lockfile_name;
+ int lockfile_fd;
+ struct flock lck = {};
+ int unique_len, ret;
+ ssize_t written;
+ bool ok;
+
+ dirlen = full_path_tos(cache_dir, "lck", buf, sizeof(buf),
+ &dir, &to_free);
+ if (dirlen == -1) {
+ return ENOMEM;
+ }
+
+ ok = directory_create_or_exist_strict(dir, sec_initial_uid(), 0755);
+ if (!ok) {
+ ret = errno;
+ DEBUG(1, ("%s: Could not create lock directory: %s\n",
+ __func__, strerror(ret)));
+ TALLOC_FREE(to_free);
+ return ret;
+ }
+
+ lockfile_name = talloc_asprintf(talloc_tos(), "%s/%u", dir,
+ (unsigned)pid);
+ TALLOC_FREE(to_free);
+ if (lockfile_name == NULL) {
+ DEBUG(1, ("%s: talloc_asprintf failed\n", __func__));
+ return ENOMEM;
+ }
+
+ /* no O_EXCL, existence check is via the fcntl lock */
+
+ lockfile_fd = open(lockfile_name, O_NONBLOCK|O_CREAT|O_WRONLY, 0644);
+ if (lockfile_fd == -1) {
+ ret = errno;
+ DEBUG(1, ("%s: open failed: %s\n", __func__, strerror(errno)));
+ goto fail_free;
+ }
+
+ lck.l_type = F_WRLCK;
+ lck.l_whence = SEEK_SET;
+ lck.l_start = 0;
+ lck.l_len = 0;
+
+ ret = fcntl(lockfile_fd, F_SETLK, &lck);
+ if (ret == -1) {
+ ret = errno;
+ DEBUG(1, ("%s: fcntl failed: %s\n", __func__, strerror(ret)));
+ goto fail_close;
+ }
+
+ unique_len = snprintf(buf, sizeof(buf), "%"PRIu64, unique);
+
+ /* shorten a potentially preexisting file */
+
+ ret = ftruncate(lockfile_fd, unique_len);
+ if (ret == -1) {
+ ret = errno;
+ DEBUG(1, ("%s: ftruncate failed: %s\n", __func__,
+ strerror(ret)));
+ goto fail_unlink;
+ }
+
+ written = write(lockfile_fd, buf, unique_len);
+ if (written != unique_len) {
+ ret = errno;
+ DEBUG(1, ("%s: write failed: %s\n", __func__, strerror(ret)));
+ goto fail_unlink;
+ }
+
+ *plockfile_fd = lockfile_fd;
+ return 0;
+
+fail_unlink:
+ unlink(lockfile_name);
+fail_close:
+ close(lockfile_fd);
+fail_free:
+ TALLOC_FREE(lockfile_name);
+ return ret;
+}
+
+static int messaging_dgm_lockfile_remove(const char *cache_dir, pid_t pid)
+{
+ fstring fname;
+ char buf[PATH_MAX];
+ char *lockfile_name, *to_free;
+ ssize_t len;
+ int ret;
+
+ fstr_sprintf(fname, "lck/%u", (unsigned)pid);
+
+ len = full_path_tos(cache_dir, fname, buf, sizeof(buf),
+ &lockfile_name, &to_free);
+ if (len == -1) {
+ return ENOMEM;
+ }
+
+ ret = unlink(lockfile_name);
+ if (ret == -1) {
+ ret = errno;
+ DEBUG(10, ("%s: unlink failed: %s\n", __func__,
+ strerror(ret)));
+ }
+ TALLOC_FREE(to_free);
+ return ret;
+}
+
+NTSTATUS messaging_dgm_init(struct messaging_context *msg_ctx,
+ TALLOC_CTX *mem_ctx,
+ struct messaging_backend **presult)
+{
+ struct messaging_backend *result;
+ struct messaging_dgm_context *ctx;
+ struct server_id pid = messaging_server_id(msg_ctx);
+ int ret;
+ bool ok;
+ const char *cache_dir;
+ char *socket_dir, *socket_name;
+ uint64_t cookie;
+
+ cache_dir = lp_cache_directory();
+ if (cache_dir == NULL) {
+ NTSTATUS status = map_nt_error_from_unix(errno);
+ return status;
+ }
+
+ result = talloc(mem_ctx, struct messaging_backend);
+ if (result == NULL) {
+ goto fail_nomem;
+ }
+ ctx = talloc_zero(result, struct messaging_dgm_context);
+ if (ctx == NULL) {
+ goto fail_nomem;
+ }
+
+ result->private_data = ctx;
+ result->send_fn = messaging_dgm_send;
+ ctx->msg_ctx = msg_ctx;
+
+ ctx->cache_dir = talloc_strdup(ctx, cache_dir);
+ if (ctx->cache_dir == NULL) {
+ goto fail_nomem;
+ }
+ socket_dir = talloc_asprintf(ctx, "%s/msg", cache_dir);
+ if (socket_dir == NULL) {
+ goto fail_nomem;
+ }
+ socket_name = talloc_asprintf(ctx, "%s/%u", socket_dir,
+ (unsigned)pid.pid);
+ if (socket_name == NULL) {
+ goto fail_nomem;
+ }
+
+ sec_init();
+
+ ret = messaging_dgm_lockfile_create(cache_dir, pid.pid,
+ &ctx->lockfile_fd, pid.unique_id);
+ if (ret != 0) {
+ DEBUG(1, ("%s: messaging_dgm_create_lockfile failed: %s\n",
+ __func__, strerror(ret)));
+ TALLOC_FREE(result);
+ return map_nt_error_from_unix(ret);
+ }
+
+ poll_funcs_init_tevent(&ctx->msg_callbacks, msg_ctx->event_ctx);
+
+ ok = directory_create_or_exist_strict(socket_dir, sec_initial_uid(),
+ 0700);
+ if (!ok) {
+ DEBUG(1, ("Could not create socket directory\n"));
+ TALLOC_FREE(result);
+ return NT_STATUS_ACCESS_DENIED;
+ }
+ TALLOC_FREE(socket_dir);
+
+ unlink(socket_name);
+
+ generate_random_buffer((uint8_t *)&cookie, sizeof(cookie));
+
+ ret = unix_msg_init(socket_name, &ctx->msg_callbacks, 1024, cookie,
+ messaging_dgm_recv, ctx, &ctx->dgm_ctx);
+ TALLOC_FREE(socket_name);
+ if (ret != 0) {
+ DEBUG(1, ("unix_msg_init failed: %s\n", strerror(ret)));
+ TALLOC_FREE(result);
+ return map_nt_error_from_unix(ret);
+ }
+ talloc_set_destructor(ctx, messaging_dgm_context_destructor);
+
+ *presult = result;
+ return NT_STATUS_OK;
+
+fail_nomem:
+ TALLOC_FREE(result);
+ return NT_STATUS_NO_MEMORY;
+}
+
+static int messaging_dgm_context_destructor(struct messaging_dgm_context *c)
+{
+ struct server_id pid = messaging_server_id(c->msg_ctx);
+
+ /*
+ * First delete the socket to avoid races. The lockfile is the
+ * indicator that we're still around.
+ */
+ unix_msg_free(c->dgm_ctx);
+
+ if (getpid() == pid.pid) {
+ (void)messaging_dgm_lockfile_remove(c->cache_dir, pid.pid);
+ }
+ close(c->lockfile_fd);
+ return 0;
+}
+
+static NTSTATUS messaging_dgm_send(struct messaging_context *msg_ctx,
+ struct server_id pid, int msg_type,
+ const DATA_BLOB *data,
+ struct messaging_backend *backend)
+{
+ struct messaging_dgm_context *ctx = talloc_get_type_abort(
+ backend->private_data, struct messaging_dgm_context);
+ fstring pid_str;
+ char buf[PATH_MAX];
+ char *dst_sock, *to_free;
+ struct messaging_dgm_hdr hdr;
+ struct iovec iov[2];
+ ssize_t pathlen;
+ int ret;
+
+ fstr_sprintf(pid_str, "msg/%u", (unsigned)pid.pid);
+
+ pathlen = full_path_tos(ctx->cache_dir, pid_str, buf, sizeof(buf),
+ &dst_sock, &to_free);
+ if (pathlen == -1) {
+ return NT_STATUS_NO_MEMORY;
+ }
+
+ hdr.msg_version = MESSAGE_VERSION;
+ hdr.msg_type = msg_type & MSG_TYPE_MASK;
+ hdr.dst = pid;
+ hdr.src = msg_ctx->id;
+
+ DEBUG(10, ("%s: Sending message 0x%x len %u to %s\n", __func__,
+ (unsigned)hdr.msg_type, (unsigned)data->length,
+ server_id_str(talloc_tos(), &pid)));
+
+ iov[0].iov_base = &hdr;
+ iov[0].iov_len = sizeof(hdr);
+ iov[1].iov_base = data->data;
+ iov[1].iov_len = data->length;
+
+ become_root();
+ ret = unix_msg_send(ctx->dgm_ctx, dst_sock, iov, ARRAY_SIZE(iov));
+ unbecome_root();
+
+ TALLOC_FREE(to_free);
+
+ if (ret != 0) {
+ return map_nt_error_from_unix(ret);
+ }
+ return NT_STATUS_OK;
+}
+
+static void messaging_dgm_recv(struct unix_msg_ctx *ctx,
+ uint8_t *msg, size_t msg_len,
+ void *private_data)
+{
+ struct messaging_dgm_context *dgm_ctx = talloc_get_type_abort(
+ private_data, struct messaging_dgm_context);
+ struct messaging_dgm_hdr *hdr;
+ struct messaging_rec rec;
+
+ if (msg_len < sizeof(*hdr)) {
+ DEBUG(1, ("message too short: %u\n", (unsigned)msg_len));
+ return;
+ }
+
+ /*
+ * unix_msg guarantees alignment, so we can cast here
+ */
+ hdr = (struct messaging_dgm_hdr *)msg;
+
+ rec.msg_version = hdr->msg_version;
+ rec.msg_type = hdr->msg_type;
+ rec.dest = hdr->dst;
+ rec.src = hdr->src;
+ rec.buf.data = msg + sizeof(*hdr);
+ rec.buf.length = msg_len - sizeof(*hdr);
+
+ DEBUG(10, ("%s: Received message 0x%x len %u from %s\n", __func__,
+ (unsigned)hdr->msg_type, (unsigned)rec.buf.length,
+ server_id_str(talloc_tos(), &rec.src)));
+
+ messaging_dispatch_rec(dgm_ctx->msg_ctx, &rec);
+}
+
+NTSTATUS messaging_dgm_cleanup(struct messaging_context *msg_ctx, pid_t pid)
+{
+ struct messaging_dgm_context *ctx = talloc_get_type_abort(
+ msg_ctx->local->private_data, struct messaging_dgm_context);
+ char *lockfile_name, *socket_name;
+ int fd, ret;
+ struct flock lck = {};
+ NTSTATUS status = NT_STATUS_OK;
+
+ lockfile_name = talloc_asprintf(talloc_tos(), "%s/lck/%u",
+ ctx->cache_dir, (unsigned)pid);
+ if (lockfile_name == NULL) {
+ return NT_STATUS_NO_MEMORY;
+ }
+ socket_name = talloc_asprintf(lockfile_name, "%s/msg/%u",
+ ctx->cache_dir, (unsigned)pid);
+ if (socket_name == NULL) {
+ TALLOC_FREE(lockfile_name);
+ return NT_STATUS_NO_MEMORY;
+ }
+
+ fd = open(lockfile_name, O_NONBLOCK|O_WRONLY, 0);
+ if (fd == -1) {
+ status = map_nt_error_from_unix(errno);
+ DEBUG(10, ("%s: open(%s) failed: %s\n", __func__,
+ lockfile_name, strerror(errno)));
+ return status;
+ }
+
+ lck.l_type = F_WRLCK;
+ lck.l_whence = SEEK_SET;
+ lck.l_start = 0;
+ lck.l_len = 0;
+
+ ret = fcntl(fd, F_SETLK, &lck);
+ if (ret != 0) {
+ status = map_nt_error_from_unix(errno);
+ DEBUG(10, ("%s: Could not get lock: %s\n", __func__,
+ strerror(errno)));
+ TALLOC_FREE(lockfile_name);
+ close(fd);
+ return status;
+ }
+
+ (void)unlink(socket_name);
+ (void)unlink(lockfile_name);
+ (void)close(fd);
+
+ TALLOC_FREE(lockfile_name);
+ return NT_STATUS_OK;
+}
git.samba.org / obnox / samba / samba-obnox.git / commitdiff