From: Wouter Wijngaards <wouter@nlnetlabs.nl>
Date: Fri, 4 Jul 2014 07:34:58 +0000 (+0000)
Subject: - Fix #593: segfault or crash upon rotating logfile.
X-Git-Tag: release-1.5.0rc1~104
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c5bf2cf802411e112f0ade9854dc650cfd81c96b;p=thirdparty%2Funbound.git

- Fix #593: segfault or crash upon rotating logfile.


git-svn-id: file:///svn/unbound/trunk@3156 be551aaa-1e26-0410-a405-d3ace91eadb9
---

diff --git a/doc/Changelog b/doc/Changelog
index 80efcb1a8..8ea4dc554 100644
--- a/doc/Changelog
+++ b/doc/Changelog
@@ -1,3 +1,6 @@
+4 July 2014: Wouter
+	- Fix #593: segfault or crash upon rotating logfile.
+
 3 July 2014: Wouter
 	- DLV tests added.
 	- signit tool fixup for compile with libldns library.
diff --git a/util/log.c b/util/log.c
index 39d3118a0..a3bffbf38 100644
--- a/util/log.c
+++ b/util/log.c
@@ -68,6 +68,8 @@ static FILE* logfile = 0;
 static int key_created = 0;
 /** pthread key for thread ids in logfile */
 static ub_thread_key_t logkey;
+/** pthread mutex to protect FILE* */
+static lock_quick_t log_lock;
 /** the identity of this executable/process */
 static const char* ident="unbound";
 #if defined(HAVE_SYSLOG_H) || defined(UB_ON_WINDOWS)
@@ -86,14 +88,19 @@ log_init(const char* filename, int use_syslog, const char* chrootdir)
 	if(!key_created) {
 		key_created = 1;
 		ub_thread_key_create(&logkey, NULL);
+		lock_quick_init(&log_lock);
 	}
+	lock_quick_lock(&log_lock);
 	if(logfile 
 #if defined(HAVE_SYSLOG_H) || defined(UB_ON_WINDOWS)
 	|| logging_to_syslog
 #endif
-	)
-	verbose(VERB_QUERY, "switching log to %s", 
-		use_syslog?"syslog":(filename&&filename[0]?filename:"stderr"));
+	) {
+		lock_quick_unlock(&log_lock); /* verbose() needs the lock */
+		verbose(VERB_QUERY, "switching log to %s", 
+			use_syslog?"syslog":(filename&&filename[0]?filename:"stderr"));
+		lock_quick_lock(&log_lock);
+	}
 	if(logfile && logfile != stderr)
 		fclose(logfile);
 #ifdef HAVE_SYSLOG_H
@@ -106,6 +113,7 @@ log_init(const char* filename, int use_syslog, const char* chrootdir)
 		 * chroot and no longer be able to access dev/log and so on */
 		openlog(ident, LOG_NDELAY, LOG_DAEMON);
 		logging_to_syslog = 1;
+		lock_quick_unlock(&log_lock);
 		return;
 	}
 #elif defined(UB_ON_WINDOWS)
@@ -114,11 +122,13 @@ log_init(const char* filename, int use_syslog, const char* chrootdir)
 	}
 	if(use_syslog) {
 		logging_to_syslog = 1;
+		lock_quick_unlock(&log_lock);
 		return;
 	}
 #endif /* HAVE_SYSLOG_H */
 	if(!filename || !filename[0]) {
 		logfile = stderr;
+		lock_quick_unlock(&log_lock);
 		return;
 	}
 	/* open the file for logging */
@@ -127,6 +137,7 @@ log_init(const char* filename, int use_syslog, const char* chrootdir)
 		filename += strlen(chrootdir);
 	f = fopen(filename, "a");
 	if(!f) {
+		lock_quick_unlock(&log_lock);
 		log_err("Could not open logfile %s: %s", filename, 
 			strerror(errno));
 		return;
@@ -136,11 +147,14 @@ log_init(const char* filename, int use_syslog, const char* chrootdir)
 	setvbuf(f, NULL, (int)_IOLBF, 0);
 #endif
 	logfile = f;
+	lock_quick_unlock(&log_lock);
 }
 
 void log_file(FILE *f)
 {
+	lock_quick_lock(&log_lock);
 	logfile = f;
+	lock_quick_unlock(&log_lock);
 }
 
 void log_thread_set(int* num)
@@ -211,7 +225,11 @@ log_vmsg(int pri, const char* type,
 		return;
 	}
 #endif /* HAVE_SYSLOG_H */
-	if(!logfile) return;
+	lock_quick_lock(&log_lock);
+	if(!logfile) {
+		lock_quick_unlock(&log_lock);
+		return;
+	}
 	if(log_now)
 		now = (time_t)*log_now;
 	else	now = (time_t)time(NULL);
@@ -236,6 +254,7 @@ log_vmsg(int pri, const char* type,
 	/* line buffering does not work on windows */
 	fflush(logfile);
 #endif
+	lock_quick_unlock(&log_lock);
 }
 
 /**