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/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
*
* Copyright (C) 2012 William Jon McCann <mccann@redhat.com>
* Copyright (C) 2012 Colin Walters <walters@verbum.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include "config.h"
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#ifdef ENABLE_SYSTEMD_JOURNAL
#include <systemd/sd-journal.h>
#endif
#include <glib-unix.h>
#define _GSYSTEM_NO_LOCAL_ALLOC
#include "libgsystem.h"
/**
* gs_log_structured:
* @message: Text message to send
* @keys: (allow-none) (array zero-terminated=1) (element-type utf8): Optional structured data
*
* Log structured data in an operating-system specific fashion. The
* parameter @opts should be an array of UTF-8 KEY=VALUE strings.
* This function does not support binary data. See
* http://www.freedesktop.org/software/systemd/man/systemd.journal-fields.html
* for more information about fields that can be used on a systemd
* system.
*/
void
gs_log_structured (const char *message,
const char *const *keys)
{
#ifdef ENABLE_SYSTEMD_JOURNAL
const char *const*iter;
char *msgkey;
guint i, n_opts;
struct iovec *iovs;
for (n_opts = 0, iter = keys; *iter; iter++, n_opts++)
;
n_opts++; /* Add one for MESSAGE= */
iovs = g_alloca (sizeof (struct iovec) * n_opts);
for (i = 0, iter = keys; *iter; iter++, i++) {
iovs[i].iov_base = (char*)keys[i];
iovs[i].iov_len = strlen (keys[i]);
}
g_assert(i == n_opts-1);
msgkey = g_strconcat ("MESSAGE=", message, NULL);
iovs[i].iov_base = msgkey;
iovs[i].iov_len = strlen (msgkey);
// The code location isn't useful since we're wrapping
#define SD_JOURNAL_SUPPRESS_LOCATION
sd_journal_sendv (iovs, n_opts);
#undef SD_JOURNAL_SUPPRESS_LOCATION
g_free (msgkey);
#else
g_print ("%s\n", message);
#endif
}
/**
* gs_stdout_is_journal:
*
* Use this function when you want your code to behave differently
* depeneding on whether your program was started as a systemd unit,
* or e.g. interactively at a terminal.
*
* Returns: %TRUE if stdout is (probably) connnected to the systemd journal
*/
gboolean
gs_stdout_is_journal (void)
{
static gsize initialized;
static gboolean stdout_is_socket;
if (g_once_init_enter (&initialized))
{
guint64 pid = (guint64) getpid ();
char *fdpath = g_strdup_printf ("/proc/%" G_GUINT64_FORMAT "/fd/1", pid);
char buf[1024];
ssize_t bytes_read;
if ((bytes_read = readlink (fdpath, buf, sizeof(buf) - 1)) != -1)
{
buf[bytes_read] = '\0';
stdout_is_socket = g_str_has_prefix (buf, "socket:");
}
else
stdout_is_socket = FALSE;
g_free (fdpath);
g_once_init_leave (&initialized, TRUE);
}
return stdout_is_socket;
}
/**
* gs_log_structured_print:
* @message: A message to log
* @keys: (allow-none) (array zero-terminated=1) (element-type utf8): Optional structured data
*
* Like gs_log_structured(), but also print to standard output (if it
* is not already connected to the system log).
*/
void
gs_log_structured_print (const char *message,
const char *const *keys)
{
gs_log_structured (message, keys);
if (!gs_stdout_is_journal ())
g_print ("%s\n", message);
}
/**
* gs_log_structured_print_id_v:
* @message_id: A unique MESSAGE_ID
* @format: A format string
*
* The provided @message_id is a unique MESSAGE_ID (see <ulink url="http://www.freedesktop.org/software/systemd/man/systemd.journal-fields.html"> for more information).
*
* This function otherwise acts as gs_log_structured_print(), taking
* @format as a format string.
*/
void
gs_log_structured_print_id_v (const char *message_id,
const char *format,
...)
{
char *keys[] = { NULL, NULL };
char *msg;
va_list args;
va_start (args, format);
msg = g_strdup_vprintf (format, args);
va_end (args);
keys[0] = g_strconcat ("MESSAGE_ID=", message_id, NULL);
gs_log_structured_print (msg, (const char *const *)keys);
g_free (keys[0]);
g_free (msg);
}
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