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Diffstat (limited to 'libgsystem/gsystem-log.c')
| -rw-r--r-- | libgsystem/gsystem-log.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/libgsystem/gsystem-log.c b/libgsystem/gsystem-log.c new file mode 100644 index 00000000..7b031453 --- /dev/null +++ b/libgsystem/gsystem-log.c @@ -0,0 +1,167 @@ +/* -*- 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 +#define SD_JOURNAL_SUPPRESS_LOCATION +#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 + sd_journal_sendv (iovs, n_opts); + + 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); + +#ifdef ENABLE_SYSTEMD_JOURNAL + if (!gs_stdout_is_journal ()) + g_print ("%s\n", message); +#endif +} + +/** + * 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); +} |