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/*
* 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 "openvswitch/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);
}
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