![[tokkee]](http://tokkee.org/images/avatar.png){kind=avatar}
diff --git a/src/utils/error.c b/src/utils/error.c
--- /dev/null
+++ b/src/utils/error.c
@@ -0,0 +1,237 @@
+/*
+ * SysDB - src/utils/error.c
+ * Copyright (C) 2013 Sebastian 'tokkee' Harl <sh@tokkee.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "utils/error.h"
+
+#include <pthread.h>
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+
+/*
+ * private data types
+ */
+
+typedef struct {
+ int prio;
+ char msg[SDB_MAX_ERROR];
+ _Bool finalized;
+} sdb_error_ctx_t;
+#define SDB_ERROR_INIT { -1, "", 1 }
+
+/*
+ * private variables
+ */
+
+static sdb_error_ctx_t default_error_ctx = SDB_ERROR_INIT;
+
+static pthread_key_t error_ctx_key;
+static _Bool error_ctx_key_initialized = 0;
+
+/*
+ * private helper functions
+ */
+
+static void
+sdb_error_ctx_init(void)
+{
+ if (error_ctx_key_initialized)
+ return;
+
+ pthread_key_create(&error_ctx_key, NULL);
+ error_ctx_key_initialized = 1;
+} /* sdb_error_init */
+
+static sdb_error_ctx_t *
+sdb_error_ctx_create(void)
+{
+ sdb_error_ctx_t *ctx;
+
+ ctx = malloc(sizeof(*ctx));
+ if (! ctx)
+ return NULL;
+
+ *ctx = default_error_ctx;
+
+ if (! error_ctx_key_initialized)
+ sdb_error_ctx_init();
+ pthread_setspecific(error_ctx_key, ctx);
+ return ctx;
+} /* sdb_error_ctx_create */
+
+static sdb_error_ctx_t *
+sdb_error_get_ctx(void)
+{
+ sdb_error_ctx_t *ctx;
+
+ if (! error_ctx_key_initialized)
+ sdb_error_ctx_init();
+ ctx = pthread_getspecific(error_ctx_key);
+
+ if (! ctx)
+ ctx = sdb_error_ctx_create();
+ if (! ctx)
+ return NULL;
+ return ctx;
+} /* sdb_error_get_ctx */
+
+static int
+sdb_error_clear(void)
+{
+ sdb_error_ctx_t *ctx;
+
+ ctx = sdb_error_get_ctx();
+ if (! ctx)
+ return -1;
+
+ ctx->prio = -1;
+ ctx->msg[0] = '\0';
+ ctx->finalized = 1;
+ return 0;
+} /* sdb_error_clear */
+
+static int
+sdb_error_vappend(int prio, const char *fmt, va_list ap)
+{
+ sdb_error_ctx_t *ctx;
+ size_t len;
+
+ ctx = sdb_error_get_ctx();
+ if (! ctx)
+ return -1;
+
+ len = strlen(ctx->msg);
+ if (len >= sizeof(ctx->msg))
+ return 0; /* nothing written */
+
+ if (prio >= 0)
+ ctx->prio = prio;
+
+ ctx->finalized = 0;
+ return vsnprintf(ctx->msg + len, sizeof(ctx->msg) - len, fmt, ap);
+} /* sdb_error_vappend */
+
+static int
+sdb_error_log(void)
+{
+ sdb_error_ctx_t *ctx;
+ int ret;
+
+ ctx = sdb_error_get_ctx();
+ if (! ctx)
+ return -1;
+
+ if (ctx->finalized)
+ return 0;
+
+ ret = fprintf(stderr, "[%s] %s\n",
+ SDB_LOG_PRIO_TO_STRING(ctx->prio), ctx->msg);
+ ctx->finalized = 1;
+ return ret;
+} /* sdb_error_log */
+
+/*
+ * public API
+ */
+
+int
+sdb_error_set(int prio, const char *fmt, ...)
+{
+ va_list ap;
+ int ret;
+
+ if (sdb_error_clear())
+ return -1;
+
+ va_start(ap, fmt);
+ ret = sdb_error_vappend(prio, fmt, ap);
+ va_end(ap);
+
+ sdb_error_log();
+ return ret;
+} /* sdb_error_set */
+
+int
+sdb_error_start(int prio, const char *fmt, ...)
+{
+ va_list ap;
+ int ret;
+
+ if (sdb_error_clear())
+ return -1;
+
+ va_start(ap, fmt);
+ ret = sdb_error_vappend(prio, fmt, ap);
+ va_end(ap);
+
+ return ret;
+} /* sdb_error_start */
+
+int
+sdb_error_append(const char *fmt, ...)
+{
+ va_list ap;
+ int ret;
+
+ va_start(ap, fmt);
+ ret = sdb_error_vappend(/* dont change prio */ -1, fmt, ap);
+ va_end(ap);
+
+ return ret;
+} /* sdb_error_append */
+
+int
+sdb_error_finish(void)
+{
+ return sdb_error_log();
+} /* sdb_error_finish */
+
+const char *
+sdb_error_get(void)
+{
+ sdb_error_ctx_t *ctx;
+
+ ctx = sdb_error_get_ctx();
+ if (! ctx)
+ return "success";
+ return ctx->msg;
+} /* sdb_error_get */
+
+int
+sdb_error_get_prio(void)
+{
+ sdb_error_ctx_t *ctx;
+
+ ctx = sdb_error_get_ctx();
+ if (! ctx)
+ return -1;
+ return ctx->prio;
+} /* sdb_error_get_prio */
+
+/* vim: set tw=78 sw=4 ts=4 noexpandtab : */
+