From bc2c68cf9316d95c5b00444aaaa2f0a6127c1aa9 Mon Sep 17 00:00:00 2001
From: Adam Dickmeiss <adam@indexdata.dk>
Date: Mon, 17 Feb 2014 16:02:10 +0100
Subject: [PATCH] Provide yaz_log_{lock,unlock}

This is to ensure yaz_log writes are atomic and allows us to use
yaz_log_lock + yaz_log_unlock in threaded+forked applications.
---
 include/yaz/log.h |    3 +++
 src/log.c         |   20 ++++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/include/yaz/log.h b/include/yaz/log.h
index 57bad18..3d7bb67 100644
--- a/include/yaz/log.h
+++ b/include/yaz/log.h
@@ -220,6 +220,9 @@ YAZ_EXPORT void log_event_end(void (*func)(int level, const char *msg,
 */
 YAZ_EXPORT void yaz_log_xml_errors(const char *prefix, int log_level);
 
+YAZ_EXPORT void yaz_log_lock(void);
+YAZ_EXPORT void yaz_log_unlock(void);
+
 YAZ_END_CDECL
 
 #endif
diff --git a/src/log.c b/src/log.c
index d78939c..b407ad9 100644
--- a/src/log.c
+++ b/src/log.c
@@ -30,6 +30,7 @@
 #include <yaz/errno.h>
 #include <yaz/thread_id.h>
 #include <yaz/log.h>
+#include <yaz/mutex.h>
 #include <yaz/snprintf.h>
 #include <yaz/xmalloc.h>
 
@@ -99,6 +100,18 @@ static struct {
 
 static unsigned int next_log_bit = YLOG_LAST_BIT<<1; /* first dynamic bit */
 
+static YAZ_MUTEX log_mutex = 0;
+
+void yaz_log_lock(void)
+{
+    yaz_mutex_enter(log_mutex);
+}
+
+void yaz_log_unlock(void)
+{
+    yaz_mutex_leave(log_mutex);
+}
+
 static void internal_log_init(void)
 {
     static int mutex_init_flag = 0; /* not yet initialized */
@@ -108,6 +121,9 @@ static void internal_log_init(void)
         return;
     mutex_init_flag = 1; /* here, 'cause nmem_mutex_create may call yaz_log */
 
+    if (log_mutex == 0)
+        yaz_mutex_create(&log_mutex);
+
     env = getenv("YAZ_LOG");
     if (env)
         l_level = yaz_log_mask_str_x(env, l_level);
@@ -342,12 +358,14 @@ static void yaz_log_do_reopen(const char *filemode)
     struct tm *tm;
 #endif
 
+    yaz_log_lock();
 #if HAVE_LOCALTIME_R
     localtime_r(&cur_time, tm);
 #else
     tm = localtime(&cur_time);
 #endif
     yaz_log_open_check(tm, 1, filemode);
+    yaz_log_unlock();
 }
 
 
@@ -379,6 +397,7 @@ static void yaz_log_to_file(int level, const char *log_message)
 
     internal_log_init();
 
+    yaz_log_lock();
 #if HAVE_LOCALTIME_R
     localtime_r(&ti, tm);
 #else
@@ -436,6 +455,7 @@ static void yaz_log_to_file(int level, const char *log_message)
         if (l_level & YLOG_FLUSH)
             fflush(file);
     }
+    yaz_log_unlock();
 }
 
 void yaz_log(int level, const char *fmt, ...)
-- 
1.7.10.4