eliminate g_error() usage

Replaced all occurrences of g_error() with MPD_ERROR() located in a new header
file 'mpd_error.h'. This macro uses g_critical() to print the error message
and then exits gracefully in contrast to g_error() which would internally call
abort() to produce a core dump.

The macro name is distinctive and allows to find all places with dubious error
handling. The long-term goal is to get rid of MPD_ERROR() altogether. To
facilitate the eventual removal of this macro it was added in a new header
file rather than to an existing header file.

This fixes #2995 and #3007.

27 files changed, 166 insertions, 103 deletions

diff --git a/src/audio.c b/src/audio.c
index 8759e255f..f9894cf3c 100644
--- a/src/audio.c
+++ b/src/audio.c
@@ -25,6 +25,7 @@
 #include "output_plugin.h"
 #include "output_all.h"
 #include "conf.h"
+#include "mpd_error.h"
 
 #include <glib.h>
 
@@ -52,6 +53,7 @@ void initAudioConfig(void)
 	ret = audio_format_parse(&configured_audio_format, param->value,
 				 true, &error);
 	if (!ret)
-		g_error("error parsing \"%s\" at line %i: %s",
-			CONF_AUDIO_OUTPUT_FORMAT, param->line, error->message);
+		MPD_ERROR("error parsing \"%s\" at line %i: %s",
+			  CONF_AUDIO_OUTPUT_FORMAT, param->line,
+			  error->message);
 }
diff --git a/src/cmdline.c b/src/cmdline.c
index 747d7c3bb..2c1db890b 100644
--- a/src/cmdline.c
+++ b/src/cmdline.c
@@ -26,6 +26,7 @@
 #include "decoder_plugin.h"
 #include "output_list.h"
 #include "ls.h"
+#include "mpd_error.h"
 
 #ifdef ENABLE_ENCODER
 #include "encoder_list.h"
@@ -155,10 +156,8 @@ parse_cmdline(int argc, char **argv, struct options *options,
 	ret = g_option_context_parse(context, &argc, &argv, &error);
 	g_option_context_free(context);
 
-	if (!ret) {
-		g_error("option parsing failed: %s\n", error->message);
-		exit(1);
-	}
+	if (!ret)
+		MPD_ERROR("option parsing failed: %s\n", error->message);
 
 	if (option_version)
 		version();
diff --git a/src/conf.c b/src/conf.c
index 476884dac..705942085 100644
--- a/src/conf.c
+++ b/src/conf.c
@@ -23,6 +23,7 @@
 #include "tokenizer.h"
 #include "path.h"
 #include "glib_compat.h"
+#include "mpd_error.h"
 
 #include <glib.h>
 
@@ -498,8 +499,8 @@ config_get_path(const char *name)
 
 	path = parsePath(param->value);
 	if (path == NULL)
-		g_error("error parsing \"%s\" at line %i\n",
-			name, param->line);
+		MPD_ERROR("error parsing \"%s\" at line %i\n",
+			  name, param->line);
 
 	g_free(param->value);
 	return param->value = path;
@@ -517,7 +518,8 @@ config_get_unsigned(const char *name, unsigned default_value)
 
 	value = strtol(param->value, &endptr, 0);
 	if (*endptr != 0 || value < 0)
-		g_error("Not a valid non-negative number in line %i", param->line);
+		MPD_ERROR("Not a valid non-negative number in line %i",
+			  param->line);
 
 	return (unsigned)value;
 }
@@ -534,10 +536,10 @@ config_get_positive(const char *name, unsigned default_value)
 
 	value = strtol(param->value, &endptr, 0);
 	if (*endptr != 0)
-		g_error("Not a valid number in line %i", param->line);
+		MPD_ERROR("Not a valid number in line %i", param->line);
 
 	if (value <= 0)
-		g_error("Not a positive number in line %i", param->line);
+		MPD_ERROR("Not a positive number in line %i", param->line);
 
 	return (unsigned)value;
 }
@@ -569,9 +571,9 @@ bool config_get_bool(const char *name, bool default_value)
 
 	success = get_bool(param->value, &value);
 	if (!success)
-		g_error("%s is not a boolean value (yes, true, 1) or "
-			"(no, false, 0) on line %i\n",
-			name, param->line);
+		MPD_ERROR("%s is not a boolean value (yes, true, 1) or "
+			  "(no, false, 0) on line %i\n",
+			  name, param->line);
 
 	return value;
 }
@@ -601,10 +603,10 @@ config_get_block_unsigned(const struct config_param *param, const char *name,
 
 	value = strtol(bp->value, &endptr, 0);
 	if (*endptr != 0)
-		g_error("Not a valid number in line %i", bp->line);
+		MPD_ERROR("Not a valid number in line %i", bp->line);
 
 	if (value < 0)
-		g_error("Not a positive number in line %i", bp->line);
+		MPD_ERROR("Not a positive number in line %i", bp->line);
 
 	return (unsigned)value;
 }
@@ -621,9 +623,9 @@ config_get_block_bool(const struct config_param *param, const char *name,
 
 	success = get_bool(bp->value, &value);
 	if (!success)
-		g_error("%s is not a boolean value (yes, true, 1) or "
-			"(no, false, 0) on line %i\n",
-			name, bp->line);
+		MPD_ERROR("%s is not a boolean value (yes, true, 1) or "
+			  "(no, false, 0) on line %i\n",
+			  name, bp->line);
 
 	return value;
 }
diff --git a/src/daemon.c b/src/daemon.c
index e08afce4b..852541375 100644
--- a/src/daemon.c
+++ b/src/daemon.c
@@ -65,23 +65,23 @@ daemonize_kill(void)
 	int pid, ret;
 
 	if (pidfile == NULL)
-		g_error("no pid_file specified in the config file");
+		MPD_ERROR("no pid_file specified in the config file");
 
 	fp = fopen(pidfile, "r");
 	if (fp == NULL)
-		g_error("unable to open pid file \"%s\": %s",
-			pidfile, g_strerror(errno));
+		MPD_ERROR("unable to open pid file \"%s\": %s",
+			  pidfile, g_strerror(errno));
 
 	if (fscanf(fp, "%i", &pid) != 1) {
-		g_error("unable to read the pid from file \"%s\"",
-			pidfile);
+		MPD_ERROR("unable to read the pid from file \"%s\"",
+			  pidfile);
 	}
 	fclose(fp);
 
 	ret = kill(pid, SIGTERM);
 	if (ret < 0)
-		g_error("unable to kill proccess %i: %s",
-			pid, g_strerror(errno));
+		MPD_ERROR("unable to kill proccess %i: %s",
+			  pid, g_strerror(errno));
 
 	exit(EXIT_SUCCESS);
 }
@@ -102,8 +102,8 @@ daemonize_set_user(void)
 	/* set gid */
 	if (user_gid != (gid_t)-1 && user_gid != getgid()) {
 		if (setgid(user_gid) == -1) {
-			g_error("cannot setgid to %d: %s",
-				(int)user_gid, g_strerror(errno));
+			MPD_ERROR("cannot setgid to %d: %s",
+				  (int)user_gid, g_strerror(errno));
 		}
 	}
 
@@ -121,8 +121,8 @@ daemonize_set_user(void)
 	/* set uid */
 	if (user_uid != (uid_t)-1 && user_uid != getuid() &&
 	    setuid(user_uid) == -1) {
-		g_error("cannot change to uid of user \"%s\": %s",
-			user_name, g_strerror(errno));
+		MPD_ERROR("cannot change to uid of user \"%s\": %s",
+			  user_name, g_strerror(errno));
 	}
 }
 
@@ -136,7 +136,7 @@ daemonize_detach(void)
 #ifdef HAVE_DAEMON
 
 	if (daemon(0, 1))
-		g_error("daemon() failed: %s", g_strerror(errno));
+		MPD_ERROR("daemon() failed: %s", g_strerror(errno));
 
 #elif defined(HAVE_FORK)
 
@@ -144,7 +144,7 @@ daemonize_detach(void)
 
 	switch (fork()) {
 	case -1:
-		g_error("fork() failed: %s", g_strerror(errno));
+		MPD_ERROR("fork() failed: %s", g_strerror(errno));
 	case 0:
 		break;
 	default:
@@ -155,14 +155,14 @@ daemonize_detach(void)
 	/* release the current working directory */
 
 	if (chdir("/") < 0)
-		g_error("problems changing to root directory");
+		MPD_ERROR("problems changing to root directory");
 
 	/* detach from the current session */
 
 	setsid();
 
 #else
-	g_error("no support for daemonizing");
+	MPD_ERROR("no support for daemonizing");
 #endif
 
 	g_debug("daemonized!");
@@ -179,8 +179,8 @@ daemonize(bool detach)
 		g_debug("opening pid file");
 		fp = fopen(pidfile, "w+");
 		if (!fp) {
-			g_error("could not create pid file \"%s\": %s",
-				pidfile, g_strerror(errno));
+			MPD_ERROR("could not create pid file \"%s\": %s",
+				  pidfile, g_strerror(errno));
 		}
 	}
 
@@ -200,7 +200,7 @@ daemonize_init(const char *user, const char *group, const char *_pidfile)
 	if (user) {
 		struct passwd *pwd = getpwnam(user);
 		if (!pwd)
-			g_error("no such user \"%s\"", user);
+			MPD_ERROR("no such user \"%s\"", user);
 
 		user_uid = pwd->pw_uid;
 		user_gid = pwd->pw_gid;
@@ -214,7 +214,7 @@ daemonize_init(const char *user, const char *group, const char *_pidfile)
 	if (group) {
 		struct group *grp = grp = getgrnam(group);
 		if (!grp)
-			g_error("no such group \"%s\"", group);
+			MPD_ERROR("no such group \"%s\"", group);
 		user_gid = grp->gr_gid;
 		had_group = true;
 	}
diff --git a/src/daemon.h b/src/daemon.h
index 4dad7e18d..71039543c 100644
--- a/src/daemon.h
+++ b/src/daemon.h
@@ -20,6 +20,8 @@
 #ifndef DAEMON_H
 #define DAEMON_H
 
+#include "mpd_error.h"
+
 #include <stdbool.h>
 
 #ifndef WIN32
@@ -51,7 +53,7 @@ daemonize_kill(void);
 #include <glib.h>
 static inline void
 daemonize_kill(void)
-{ g_error("--kill is not available on WIN32"); }
+{ MPD_ERROR("--kill is not available on WIN32"); }
 #endif
 
 /**
diff --git a/src/decoder/mikmod_decoder_plugin.c b/src/decoder/mikmod_decoder_plugin.c
index 50b46f2af..91478e86f 100644
--- a/src/decoder/mikmod_decoder_plugin.c
+++ b/src/decoder/mikmod_decoder_plugin.c
@@ -19,6 +19,7 @@
 
 #include "config.h"
 #include "decoder_api.h"
+#include "mpd_error.h"
 
 #include <glib.h>
 #include <mikmod.h>
@@ -110,8 +111,8 @@ mikmod_decoder_init(const struct config_param *param)
 	mikmod_sample_rate = config_get_block_unsigned(param, "sample_rate",
 						       44100);
 	if (!audio_valid_sample_rate(mikmod_sample_rate))
-		g_error("Invalid sample rate in line %d: %u",
-			param->line, mikmod_sample_rate);
+		MPD_ERROR("Invalid sample rate in line %d: %u",
+			  param->line, mikmod_sample_rate);
 
 	md_device = 0;
 	md_reverb = 0;
diff --git a/src/decoder_list.c b/src/decoder_list.c
index f91d635dc..d76050023 100644
--- a/src/decoder_list.c
+++ b/src/decoder_list.c
@@ -22,6 +22,7 @@
 #include "decoder_plugin.h"
 #include "utils.h"
 #include "conf.h"
+#include "mpd_error.h"
 
 #include <glib.h>
 
@@ -198,8 +199,8 @@ decoder_plugin_config(const char *plugin_name)
 		const char *name =
 			config_get_block_string(param, "plugin", NULL);
 		if (name == NULL)
-			g_error("decoder configuration without 'plugin' name in line %d",
-				param->line);
+			MPD_ERROR("decoder configuration without 'plugin' name in line %d",
+				  param->line);
 
 		if (strcmp(name, plugin_name) == 0)
 			return param;
diff --git a/src/decoder_thread.c b/src/decoder_thread.c
index a75f09d37..1a91b6566 100644
--- a/src/decoder_thread.c
+++ b/src/decoder_thread.c
@@ -32,6 +32,7 @@
 #include "mapper.h"
 #include "path.h"
 #include "uri.h"
+#include "mpd_error.h"
 
 #include <glib.h>
 
@@ -479,5 +480,5 @@ decoder_thread_start(struct decoder_control *dc)
 
 	dc->thread = g_thread_create(decoder_task, dc, true, &e);
 	if (dc->thread == NULL)
-		g_error("Failed to spawn decoder task: %s", e->message);
+		MPD_ERROR("Failed to spawn decoder task: %s", e->message);
 }
diff --git a/src/encoder/vorbis_encoder.c b/src/encoder/vorbis_encoder.c
index 0cb8b1b60..986135789 100644
--- a/src/encoder/vorbis_encoder.c
+++ b/src/encoder/vorbis_encoder.c
@@ -22,6 +22,7 @@
 #include "encoder_plugin.h"
 #include "tag.h"
 #include "audio_format.h"
+#include "mpd_error.h"
 
 #include <vorbis/vorbisenc.h>
 
@@ -374,7 +375,7 @@ vorbis_encoder_read(struct encoder *_encoder, void *_dest, size_t length)
 
 	if (nbytes > length)
 		/* XXX better error handling */
-		g_error("buffer too small");
+		MPD_ERROR("buffer too small");
 
 	memcpy(dest, page.header, page.header_len);
 	memcpy(dest + page.header_len, page.body, page.body_len);
diff --git a/src/event_pipe.c b/src/event_pipe.c
index 286256f96..5b519984f 100644
--- a/src/event_pipe.c
+++ b/src/event_pipe.c
@@ -20,6 +20,7 @@
 #include "config.h"
 #include "event_pipe.h"
 #include "fd_util.h"
+#include "mpd_error.h"
 
 #include <stdbool.h>
 #include <assert.h>
@@ -68,7 +69,7 @@ main_notify_event(G_GNUC_UNUSED GIOChannel *source,
 						   buffer, sizeof(buffer),
 						   &bytes_read, &error);
 	if (status == G_IO_STATUS_ERROR)
-		g_error("error reading from pipe: %s", error->message);
+		MPD_ERROR("error reading from pipe: %s", error->message);
 
 	bool events[PIPE_EVENT_MAX];
 	g_mutex_lock(event_pipe_mutex);
@@ -91,7 +92,7 @@ void event_pipe_init(void)
 
 	ret = pipe_cloexec_nonblock(event_pipe);
 	if (ret < 0)
-		g_error("Couldn't open pipe: %s", strerror(errno));
+		MPD_ERROR("Couldn't open pipe: %s", strerror(errno));
 
 #ifndef G_OS_WIN32
 	channel = g_io_channel_unix_new(event_pipe[0]);
@@ -150,7 +151,7 @@ void event_pipe_emit(enum pipe_event event)
 
 	w = write(event_pipe[1], "", 1);
 	if (w < 0 && errno != EAGAIN && errno != EINTR)
-		g_error("error writing to pipe: %s", strerror(errno));
+		MPD_ERROR("error writing to pipe: %s", strerror(errno));
 }
 
 void event_pipe_emit_fast(enum pipe_event event)
diff --git a/src/inotify_source.c b/src/inotify_source.c
index d4b047fe1..3a986cbad 100644
--- a/src/inotify_source.c
+++ b/src/inotify_source.c
@@ -21,6 +21,7 @@
 #include "inotify_source.h"
 #include "fifo_buffer.h"
 #include "fd_util.h"
+#include "mpd_error.h"
 
 #include <sys/inotify.h>
 #include <unistd.h>
@@ -68,13 +69,14 @@ mpd_inotify_in_event(G_GNUC_UNUSED GIOChannel *_source,
 
 	dest = fifo_buffer_write(source->buffer, &length);
 	if (dest == NULL)
-		g_error("buffer full");
+		MPD_ERROR("buffer full");
 
 	nbytes = read(source->fd, dest, length);
 	if (nbytes < 0)
-		g_error("failed to read from inotify: %s", g_strerror(errno));
+		MPD_ERROR("failed to read from inotify: %s",
+			  g_strerror(errno));
 	if (nbytes == 0)
-		g_error("end of file from inotify");
+		MPD_ERROR("end of file from inotify");
 
 	fifo_buffer_append(source->buffer, nbytes);
 
diff --git a/src/log.c b/src/log.c
index dc7628871..556c8b04f 100644
--- a/src/log.c
+++ b/src/log.c
@@ -22,6 +22,7 @@
 #include "conf.h"
 #include "utils.h"
 #include "fd_util.h"
+#include "mpd_error.h"
 
 #include <assert.h>
 #include <sys/types.h>
@@ -60,9 +61,9 @@ static void redirect_logs(int fd)
 {
 	assert(fd >= 0);
 	if (dup2(fd, STDOUT_FILENO) < 0)
-		g_error("problems dup2 stdout : %s\n", strerror(errno));
+		MPD_ERROR("problems dup2 stdout : %s\n", strerror(errno));
 	if (dup2(fd, STDERR_FILENO) < 0)
-		g_error("problems dup2 stderr : %s\n", strerror(errno));
+		MPD_ERROR("problems dup2 stderr : %s\n", strerror(errno));
 }
 
 static const char *log_date(void)
@@ -138,8 +139,8 @@ log_init_file(const char *path, unsigned line)
 	out_filename = path;
 	out_fd = open_log_file();
 	if (out_fd < 0)
-		g_error("problem opening log file \"%s\" (config line %u) for "
-			"writing\n", path, line);
+		MPD_ERROR("problem opening log file \"%s\" (config line %u) "
+			  "for writing\n", path, line);
 
 	g_log_set_default_handler(file_log_func, NULL);
 }
@@ -216,8 +217,8 @@ parse_log_level(const char *value, unsigned line)
 	else if (0 == strcmp(value, "verbose"))
 		return G_LOG_LEVEL_DEBUG;
 	else {
-		g_error("unknown log level \"%s\" at line %u\n",
-			value, line);
+		MPD_ERROR("unknown log level \"%s\" at line %u\n",
+			  value, line);
 		return G_LOG_LEVEL_MESSAGE;
 	}
 }
@@ -252,8 +253,8 @@ void log_init(bool verbose, bool use_stdout)
 			   available) */
 			log_init_syslog();
 #else
-			g_error("config parameter \"%s\" not found\n",
-				CONF_LOG_FILE);
+			MPD_ERROR("config parameter \"%s\" not found\n",
+				  CONF_LOG_FILE);
 #endif
 #ifdef HAVE_SYSLOG
 		} else if (strcmp(param->value, "syslog") == 0) {
diff --git a/src/main.c b/src/main.c
index 34310927d..a500e2934 100644
--- a/src/main.c
+++ b/src/main.c
@@ -54,6 +54,7 @@
 #include "dirvec.h"
 #include "songvec.h"
 #include "tag_pool.h"
+#include "mpd_error.h"
 
 #ifdef ENABLE_INOTIFY
 #include "inotify_update.h"
@@ -141,7 +142,7 @@ glue_db_init_and_load(void)
 	}
 
 	if (path == NULL)
-		g_error(CONF_DB_FILE " setting missing");
+		MPD_ERROR(CONF_DB_FILE " setting missing");
 
 	db_init(path);
 
@@ -175,7 +176,7 @@ glue_sticker_init(void)
 	success = sticker_global_init(config_get_path(CONF_STICKER_FILE),
 				      &error);
 	if (!success)
-		g_error("%s", error->message);
+		MPD_ERROR("%s", error->message);
 #endif
 }
 
@@ -197,14 +198,14 @@ static void winsock_init(void)
 	retval = WSAStartup(MAKEWORD(2, 2), &sockinfo);
 	if(retval != 0)
 	{
-		g_error("Attempt to open Winsock2 failed; error code %d\n",
+		MPD_ERROR("Attempt to open Winsock2 failed; error code %d\n",
 			retval);
 	}
 
 	if (LOBYTE(sockinfo.wVersion) != 2)
 	{
-		g_error("We use Winsock2 but your version is either too new or "
-			"old; please install Winsock 2.x\n");
+		MPD_ERROR("We use Winsock2 but your version is either too new "
+			  "or old; please install Winsock 2.x\n");
 	}
 #endif
 }
@@ -226,8 +227,8 @@ initialize_decoder_and_player(void)
 	if (param != NULL) {
 		buffer_size = strtol(param->value, &test, 10);
 		if (*test != '\0' || buffer_size <= 0)
-			g_error("buffer size \"%s\" is not a positive integer, "
-				"line %i\n", param->value, param->line);
+			MPD_ERROR("buffer size \"%s\" is not a positive integer, "
+				  "line %i\n", param->value, param->line);
 	} else
 		buffer_size = DEFAULT_BUFFER_SIZE;
 
@@ -236,15 +237,15 @@ initialize_decoder_and_player(void)
 	buffered_chunks = buffer_size / CHUNK_SIZE;
 
 	if (buffered_chunks >= 1 << 15)
-		g_error("buffer size \"%li\" is too big\n", (long)buffer_size);
+		MPD_ERROR("buffer size \"%li\" is too big\n", (long)buffer_size);
 
 	param = config_get_param(CONF_BUFFER_BEFORE_PLAY);
 	if (param != NULL) {
 		perc = strtod(param->value, &test);
 		if (*test != '%' || perc < 0 || perc > 100) {
-			g_error("buffered before play \"%s\" is not a positive "
-				"percentage and less than 100 percent, line %i",
-				param->value, param->line);
+			MPD_ERROR("buffered before play \"%s\" is not a positive "
+				  "percentage and less than 100 percent, line %i",
+				  param->value, param->line);
 		}
 	} else
 		perc = DEFAULT_BUFFER_BEFORE_PLAY;
@@ -390,7 +391,7 @@ int mpd_main(int argc, char *argv[])
 		   database */
 		unsigned job = update_enqueue(NULL, true);
 		if (job == 0)
-			g_error("directory update failed");
+			MPD_ERROR("directory update failed");
 	}
 
 	glue_state_file_init();
diff --git a/src/mpd_error.h b/src/mpd_error.h
new file mode 100644
index 000000000..95e120572
--- /dev/null
+++ b/src/mpd_error.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2003-2010 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * 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 2 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, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_ERROR_H
+#define MPD_ERROR_H
+
+#include <stdlib.h>
+
+/* This macro is used as an intermediate step to a proper error handling
+ * using GError in mpd. It is used for unrecoverable error conditions
+ * and exits immediately. The long-term goal is to replace this macro by
+ * proper error handling. */
+
+#define MPD_ERROR(...) \
+	{ \
+		g_critical(__VA_ARGS__); \
+		exit(EXIT_FAILURE); \
+	}
+
+#endif
diff --git a/src/output/shout_plugin.c b/src/output/shout_plugin.c
index a8b409be2..d1466eb3a 100644
--- a/src/output/shout_plugin.c
+++ b/src/output/shout_plugin.c
@@ -21,6 +21,7 @@
 #include "output_api.h"
 #include "encoder_plugin.h"
 #include "encoder_list.h"
+#include "mpd_error.h"
 
 #include <shout/shout.h>
 #include <glib.h>
@@ -101,8 +102,8 @@ static void free_shout_data(struct shout_data *sd)
 #define check_block_param(name) {		  \
 		block_param = config_get_block_param(param, name);	\
 		if (!block_param) {					\
-			g_error("no \"%s\" defined for shout device defined at line " \
-				"%i\n", name, param->line);		\
+			MPD_ERROR("no \"%s\" defined for shout device defined at line " \
+				  "%i\n", name, param->line);		\
 		}							\
 	}
 
diff --git a/src/output_all.c b/src/output_all.c
index dbd5a6ce6..3f582dcb4 100644
--- a/src/output_all.c
+++ b/src/output_all.c
@@ -26,6 +26,7 @@
 #include "pipe.h"
 #include "buffer.h"
 #include "player_control.h"
+#include "mpd_error.h"
 
 #ifndef NDEBUG
 #include "chunk.h"
@@ -122,17 +123,17 @@ audio_output_all_init(void)
 
 		if (!audio_output_init(output, param, &error)) {
 			if (param != NULL)
-				g_error("line %i: %s",
-					param->line, error->message);
+				MPD_ERROR("line %i: %s",
+					  param->line, error->message)
 			else
-				g_error("%s", error->message);
+				MPD_ERROR("%s", error->message);
 		}
 
 		/* require output names to be unique: */
 		for (j = 0; j < i; j++) {
 			if (!strcmp(output->name, audio_outputs[j].name)) {
-				g_error("output devices with identical "
-					"names: %s\n", output->name);
+				MPD_ERROR("output devices with identical "
+					  "names: %s\n", output->name);
 			}
 		}
 	}
diff --git a/src/output_thread.c b/src/output_thread.c
index df9d7801b..c10a1552f 100644
--- a/src/output_thread.c
+++ b/src/output_thread.c
@@ -28,6 +28,7 @@
 #include "filter_plugin.h"
 #include "filter/convert_filter_plugin.h"
 #include "filter/replay_gain_filter_plugin.h"
+#include "mpd_error.h"
 
 #include <glib.h>
 
@@ -629,5 +630,5 @@ void audio_output_thread_start(struct audio_output *ao)
 	assert(ao->command == AO_COMMAND_NONE);
 
 	if (!(ao->thread = g_thread_create(audio_output_task, ao, true, &e)))
-		g_error("Failed to spawn output task: %s\n", e->message);
+		MPD_ERROR("Failed to spawn output task: %s\n", e->message);
 }
diff --git a/src/path.c b/src/path.c
index 96c429529..5e39c1636 100644
--- a/src/path.c
+++ b/src/path.c
@@ -20,6 +20,7 @@
 #include "config.h"
 #include "path.h"
 #include "conf.h"
+#include "mpd_error.h"
 
 #include <glib.h>
 
@@ -64,7 +65,7 @@ path_set_fs_charset(const char *charset)
 	/* convert a space to ensure that the charset is valid */
 	test = g_convert(" ", 1, charset, "UTF-8", NULL, NULL, NULL);
 	if (test == NULL)
-		g_error("invalid filesystem charset: %s", charset);
+		MPD_ERROR("invalid filesystem charset: %s", charset);
 	g_free(test);
 
 	g_free(fs_charset);
diff --git a/src/pcm_mix.c b/src/pcm_mix.c
index 33815dac2..3145c07be 100644
--- a/src/pcm_mix.c
+++ b/src/pcm_mix.c
@@ -22,6 +22,7 @@
 #include "pcm_volume.h"
 #include "pcm_utils.h"
 #include "audio_format.h"
+#include "mpd_error.h"
 
 #include <glib.h>
 
@@ -125,8 +126,8 @@ pcm_add_vol(void *buffer1, const void *buffer2, size_t size,
 		break;
 
 	default:
-		g_error("format %s not supported by pcm_add_vol",
-			sample_format_to_string(format->format));
+		MPD_ERROR("format %s not supported by pcm_add_vol",
+			  sample_format_to_string(format->format));
 	}
 }
 
@@ -208,8 +209,8 @@ pcm_add(void *buffer1, const void *buffer2, size_t size,
 		break;
 
 	default:
-		g_error("format %s not supported by pcm_add",
-			sample_format_to_string(format->format));
+		MPD_ERROR("format %s not supported by pcm_add",
+			  sample_format_to_string(format->format));
 	}
 }
 
diff --git a/src/permission.c b/src/permission.c
index ce47effe8..17b443e0a 100644
--- a/src/permission.c
+++ b/src/permission.c
@@ -20,6 +20,7 @@
 #include "config.h"
 #include "permission.h"
 #include "conf.h"
+#include "mpd_error.h"
 
 #include <glib.h>
 
@@ -59,7 +60,7 @@ static unsigned parsePermissions(const char *string)
 		} else if (strcmp(temp, PERMISSION_ADMIN_STRING) == 0) {
 			permission |= PERMISSION_ADMIN;
 		} else {
-			g_error("unknown permission \"%s\"", temp);
+			MPD_ERROR("unknown permission \"%s\"", temp);
 		}
 	}
 
@@ -90,7 +91,7 @@ void initPermissions(void)
 				strchr(param->value, PERMISSION_PASSWORD_CHAR);
 
 			if (separator == NULL)
-				g_error("\"%c\" not found in password string "
+				MPD_ERROR("\"%c\" not found in password string "
 					"\"%s\", line %i",
 					PERMISSION_PASSWORD_CHAR,
 					param->value, param->line);
diff --git a/src/player_thread.c b/src/player_thread.c
index cf4e61384..13d1c2ebb 100644
--- a/src/player_thread.c
+++ b/src/player_thread.c
@@ -34,6 +34,7 @@
 #include "idle.h"
 #include "main.h"
 #include "buffer.h"
+#include "mpd_error.h"
 
 #include <glib.h>
 
@@ -1073,5 +1074,5 @@ void player_create(void)
 
 	pc.thread = g_thread_create(player_task, NULL, true, &e);
 	if (pc.thread == NULL)
-		g_error("Failed to spawn player task: %s", e->message);
+		MPD_ERROR("Failed to spawn player task: %s", e->message);
 }
diff --git a/src/playlist_list.c b/src/playlist_list.c
index 9c40e6dfe..9bd73ea93 100644
--- a/src/playlist_list.c
+++ b/src/playlist_list.c
@@ -33,6 +33,7 @@
 #include "utils.h"
 #include "conf.h"
 #include "glib_compat.h"
+#include "mpd_error.h"
 
 #include <assert.h>
 #include <string.h>
@@ -76,7 +77,7 @@ playlist_plugin_config(const char *plugin_name)
 		const char *name =
 			config_get_block_string(param, "name", NULL);
 		if (name == NULL)
-			g_error("playlist configuration without 'plugin' name in line %d",
+			MPD_ERROR("playlist configuration without 'plugin' name in line %d",
 				param->line);
 
 		if (strcmp(name, plugin_name) == 0)
diff --git a/src/replay_gain_config.c b/src/replay_gain_config.c
index f82725e90..bbfe127a7 100644
--- a/src/replay_gain_config.c
+++ b/src/replay_gain_config.c
@@ -22,6 +22,7 @@
 #include "playlist.h"
 #include "conf.h"
 #include "idle.h"
+#include "mpd_error.h"
 
 #include <glib.h>
 
@@ -91,8 +92,8 @@ void replay_gain_global_init(void)
 	const struct config_param *param = config_get_param(CONF_REPLAYGAIN);
 
 	if (param != NULL && !replay_gain_set_mode_string(param->value)) {
-		g_error("replaygain value \"%s\" at line %i is invalid\n",
-			param->value, param->line);
+		MPD_ERROR("replaygain value \"%s\" at line %i is invalid\n",
+			  param->value, param->line);
 	}
 
 	param = config_get_param(CONF_REPLAYGAIN_PREAMP);
@@ -102,13 +103,13 @@ void replay_gain_global_init(void)
 		float f = strtod(param->value, &test);
 
 		if (*test != '\0') {
-			g_error("Replaygain preamp \"%s\" is not a number at "
-				"line %i\n", param->value, param->line);
+			MPD_ERROR("Replaygain preamp \"%s\" is not a number at "
+				  "line %i\n", param->value, param->line);
 		}
 
 		if (f < -15 || f > 15) {
-			g_error("Replaygain preamp \"%s\" is not between -15 and"
-				"15 at line %i\n", param->value, param->line);
+			MPD_ERROR("Replaygain preamp \"%s\" is not between -15 and"
+				  "15 at line %i\n", param->value, param->line);
 		}
 
 		replay_gain_preamp = pow(10, f / 20.0);
@@ -121,13 +122,13 @@ void replay_gain_global_init(void)
 		float f = strtod(param->value, &test);
 
 		if (*test != '\0') {
-			g_error("Replaygain missing preamp \"%s\" is not a number at "
-				"line %i\n", param->value, param->line);
+			MPD_ERROR("Replaygain missing preamp \"%s\" is not a number at "
+				  "line %i\n", param->value, param->line);
 		}
 
 		if (f < -15 || f > 15) {
-			g_error("Replaygain missing preamp \"%s\" is not between -15 and"
-				"15 at line %i\n", param->value, param->line);
+			MPD_ERROR("Replaygain missing preamp \"%s\" is not between -15 and"
+				  "15 at line %i\n", param->value, param->line);
 		}
 
 		replay_gain_missing_preamp = pow(10, f / 20.0);
diff --git a/src/sig_handlers.c b/src/sig_handlers.c
index 99a0b7e06..8aa85cf88 100644
--- a/src/sig_handlers.c
+++ b/src/sig_handlers.c
@@ -25,6 +25,7 @@
 #include "log.h"
 #include "main.h"
 #include "event_pipe.h"
+#include "mpd_error.h"
 
 #include <glib.h>
 
@@ -46,7 +47,7 @@ static void
 x_sigaction(int signum, const struct sigaction *act)
 {
 	if (sigaction(signum, act, NULL) < 0)
-		g_error("sigaction() failed: %s", strerror(errno));
+		MPD_ERROR("sigaction() failed: %s", strerror(errno));
 }
 
 static void
diff --git a/src/tag.c b/src/tag.c
index aa96a468f..6ce46a831 100644
--- a/src/tag.c
+++ b/src/tag.c
@@ -23,6 +23,7 @@
 #include "tag_pool.h"
 #include "conf.h"
 #include "song.h"
+#include "mpd_error.h"
 
 #include <glib.h>
 #include <assert.h>
@@ -138,8 +139,8 @@ void tag_lib_init(void)
 
 			type = tag_name_parse_i(c);
 			if (type == TAG_NUM_OF_ITEM_TYPES)
-				g_error("error parsing metadata item \"%s\"",
-					c);
+				MPD_ERROR("error parsing metadata item \"%s\"",
+					  c);
 
 			ignore_tag_items[type] = false;
 
diff --git a/src/update.c b/src/update.c
index 83436612f..d57fb114d 100644
--- a/src/update.c
+++ b/src/update.c
@@ -28,6 +28,7 @@
 #include "idle.h"
 #include "stats.h"
 #include "main.h"
+#include "mpd_error.h"
 
 #include <glib.h>
 
@@ -93,7 +94,7 @@ spawn_update_task(const char *path)
 
 	update_thr = g_thread_create(update_task, g_strdup(path), TRUE, &e);
 	if (update_thr == NULL)
-		g_error("Failed to spawn update task: %s", e->message);
+		MPD_ERROR("Failed to spawn update task: %s", e->message);
 
 	if (++update_task_id > update_task_id_max)
 		update_task_id = 1;
diff --git a/src/zeroconf-avahi.c b/src/zeroconf-avahi.c
index d9b0c22a8..518a7a481 100644
--- a/src/zeroconf-avahi.c
+++ b/src/zeroconf-avahi.c
@@ -20,6 +20,7 @@
 #include "config.h"
 #include "zeroconf-internal.h"
 #include "listen.h"
+#include "mpd_error.h"
 
 #include <glib.h>
 
@@ -218,7 +219,7 @@ void init_avahi(const char *serviceName)
 	g_debug("Initializing interface");
 
 	if (!avahi_is_valid_service_name(serviceName))
-		g_error("Invalid zeroconf_name \"%s\"", serviceName);
+		MPD_ERROR("Invalid zeroconf_name \"%s\"", serviceName);
 
 	avahiName = avahi_strdup(serviceName);