+/*
+ * Copyright (c) 2015 Nicira, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "syslog-direct.h"
+
+#include <config.h>
+
+#include <string.h>
+#include <unistd.h>
+
+#include "compiler.h"
+#include "dynamic-string.h"
+#include "socket-util.h"
+#include "syslog-provider.h"
+#include "util.h"
+
+#define FACILITY_MASK 0x03f8
+
+static void syslog_direct_open(struct syslogger *this, int facility);
+static void syslog_direct_log(struct syslogger *this, int pri,
+ const char *msg);
+
+static struct syslog_class syslog_direct_class = {
+ syslog_direct_open,
+ syslog_direct_log,
+};
+
+struct syslog_direct {
+ struct syslogger parent;
+ int fd; /* Negative number in error case. Otherwise, socket. */
+ int facility;
+};
+
+
+/* This function creates object that directly interacts with syslog over
+ * UDP or Unix domain socket specified in 'method'. */
+struct syslogger *
+syslog_direct_create(const char *method)
+{
+ struct syslog_direct *this = xmalloc(sizeof *this);
+
+ this->parent.class = &syslog_direct_class;
+ this->parent.prefix = "<%B>";
+
+ /* socket is created from here (opposed to syslog_direct_open())
+ * so that deadlocks would be avoided. The problem is that these
+ * functions that create socket might call VLOG() */
+ if (!strncmp(method, "udp:", 4)) {
+ inet_open_active(SOCK_DGRAM, &method[4], 514, NULL, &this->fd, 0);
+ } else if (!strncmp(method, "unix:", 5)) {
+ this->fd = make_unix_socket(SOCK_DGRAM, true, NULL, &method[5]);
+ } else {
+ this->fd = -1;
+ }
+
+ return &this->parent;
+}
+
+static void
+syslog_direct_open(struct syslogger *this, int facility)
+{
+ struct syslog_direct *this_ = (struct syslog_direct*) this;
+
+ this_->facility = facility;
+}
+
+static void
+syslog_direct_log(struct syslogger *this, int pri, const char *msg)
+{
+ static size_t max_len = SIZE_MAX; /* max message size we have discovered
+ * to be able to send() without failing
+ * with EMSGSIZE. */
+
+ struct syslog_direct *this_ = (struct syslog_direct*) this;
+ struct ds ds = DS_EMPTY_INITIALIZER;
+ const char *wire_msg;
+ size_t send_len;
+
+ if (this_->fd < 0) {
+ /* Failed to open socket for logging. */
+ return;
+ }
+
+ if (!(pri & FACILITY_MASK)) {
+ pri |= this_->facility;
+ }
+ ds_put_format(&ds, "<%u>%s", pri, msg);
+ wire_msg = ds_cstr(&ds);
+ send_len = MIN(strlen(wire_msg), max_len);;
+ while (send(this_->fd, wire_msg, send_len, 0) < 0 && errno == EMSGSIZE) {
+ /* If message was too large for send() function then try to discover
+ * max_len supported for this particular socket and retry sending a
+ * truncated version of the same message. */
+ send_len -= send_len / 20;
+ max_len = send_len;
+ }
+ ds_destroy(&ds);
+}