utils: Move thread-safe strerror replacement to a separate file

For some utils _GNU_SOURCE might be needed but that conflicts with the
signature of strerror_r(3).

src/libstrongswan/Android.mk

@@ -36,7 +36,8 @@ selectors/traffic_selector.c threading/thread.c threading/thread_value.c \
 threading/mutex.c threading/semaphore.c threading/rwlock.c threading/spinlock.c \
 utils/utils.c utils/chunk.c utils/debug.c utils/enum.c utils/identification.c \
 utils/lexparser.c utils/optionsfrom.c utils/capabilities.c utils/backtrace.c \
-utils/printf_hook/printf_hook_builtin.c utils/settings.c utils/test.c
+utils/printf_hook/printf_hook_builtin.c utils/settings.c utils/test.c \
+utils/utils/strerror.c
 
 # adding the plugin source files
 

src/libstrongswan/Makefile.am

@@ -34,7 +34,8 @@ selectors/traffic_selector.c threading/thread.c threading/thread_value.c \
 threading/mutex.c threading/semaphore.c threading/rwlock.c threading/spinlock.c \
 utils/utils.c utils/chunk.c utils/debug.c utils/enum.c utils/identification.c \
 utils/lexparser.c utils/optionsfrom.c utils/capabilities.c utils/backtrace.c \
-utils/settings.c utils/test.c
+utils/settings.c utils/test.c \
+utils/utils/strerror.c
 
 if USE_DEV_HEADERS
 strongswan_includedir = ${dev_headers}
@@ -82,7 +83,8 @@ utils/utils.h utils/chunk.h utils/debug.h utils/enum.h utils/identification.h \
 utils/lexparser.h utils/optionsfrom.h utils/capabilities.h utils/backtrace.h \
 utils/leak_detective.h utils/printf_hook/printf_hook.h \
 utils/printf_hook/printf_hook_vstr.h utils/printf_hook/printf_hook_builtin.h \
-utils/settings.h utils/test.h utils/integrity_checker.h
+utils/settings.h utils/test.h utils/integrity_checker.h \
+utils/utils/strerror.h
 endif
 
 library.lo :	$(top_builddir)/config.status

src/libstrongswan/utils/leak_detective.c

@@ -499,7 +499,7 @@ static bool register_hooks()
 char *whitelist[] = {
 	/* backtraces, including own */
 	"backtrace_create",
-	"safe_strerror",
+	"strerror_safe",
 	/* pthread stuff */
 	"pthread_create",
 	"pthread_setspecific",

src/libstrongswan/utils/utils.c

@@ -303,84 +303,6 @@ char* tty_escape_get(int fd, tty_escape_t escape)
 	return "";
 }
 
-/**
- * The size of the thread-specific error buffer
- */
-#define STRERROR_BUF_LEN 256
-
-/**
- * Key to store thread-specific error buffer
- */
-static pthread_key_t strerror_buf_key;
-
-/**
- * Only initialize the key above once
- */
-static pthread_once_t strerror_buf_key_once = PTHREAD_ONCE_INIT;
-
-/**
- * Create the key used for the thread-specific error buffer
- */
-static void create_strerror_buf_key()
-{
-	pthread_key_create(&strerror_buf_key, free);
-}
-
-/**
- * Retrieve the error buffer assigned to the current thread (or create it)
- */
-static inline char *get_strerror_buf()
-{
-	char *buf;
-
-	pthread_once(&strerror_buf_key_once, create_strerror_buf_key);
-	buf = pthread_getspecific(strerror_buf_key);
-	if (!buf)
-	{
-		buf = malloc(STRERROR_BUF_LEN);
-		pthread_setspecific(strerror_buf_key, buf);
-	}
-	return buf;
-}
-
-#ifdef HAVE_STRERROR_R
-/*
- * Described in header.
- */
-const char *safe_strerror(int errnum)
-{
-	char *buf = get_strerror_buf(), *msg;
-
-#ifdef STRERROR_R_CHAR_P
-	/* char* version which may or may not return the original buffer */
-	msg = strerror_r(errnum, buf, STRERROR_BUF_LEN);
-#else
-	/* int version returns 0 on success */
-	msg = strerror_r(errnum, buf, STRERROR_BUF_LEN) ? "Unknown error" : buf;
-#endif
-	return msg;
-}
-#else /* HAVE_STRERROR_R */
-/* we actually wan't to call strerror(3) below */
-#undef strerror
-/*
- * Described in header.
- */
-const char *safe_strerror(int errnum)
-{
-	static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
-	char *buf = get_strerror_buf();
-
-	/* use a mutex to ensure calling strerror(3) is thread-safe */
-	pthread_mutex_lock(&mutex);
-	strncpy(buf, strerror(errnum), STRERROR_BUF_LEN);
-	pthread_mutex_unlock(&mutex);
-	buf[STRERROR_BUF_LEN - 1] = '\0';
-	return buf;
-}
-#endif /* HAVE_STRERROR_R */
-
-
 #ifndef HAVE_CLOSEFROM
 /**
  * Described in header.

src/libstrongswan/utils/utils.h

@@ -30,6 +30,7 @@
 #include <string.h>
 
 #include "enum.h"
+#include "utils/strerror.h"
 
 /**
  * strongSwan program return codes
@@ -494,23 +495,6 @@ char *strreplace(const char *str, const char *search, const char *replace);
  */
 bool mkdir_p(const char *path, mode_t mode);
 
-/**
- * Thread-safe wrapper around strerror and strerror_r.
- *
- * This is required because the first is not thread-safe (on some platforms)
- * and the second uses two different signatures (POSIX/GNU) and is impractical
- * to use anyway.
- *
- * @param errnum	error code (i.e. errno)
- * @return			error message
- */
-const char *safe_strerror(int errnum);
-
-/**
- * Replace usages of strerror(3) with thread-safe variant.
- */
-#define strerror(errnum) safe_strerror(errnum)
-
 #ifndef HAVE_CLOSEFROM
 /**
  * Close open file descriptors greater than or equal to lowfd.

src/libstrongswan/utils/utils/strerror.c

@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2012-2014 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * 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.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * 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.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <pthread.h>
+
+#include "strerror.h"
+
+/**
+ * The size of the thread-specific error buffer
+ */
+#define STRERROR_BUF_LEN 256
+
+/**
+ * Key to store thread-specific error buffer
+ */
+static pthread_key_t strerror_buf_key;
+
+/**
+ * Only initialize the key above once
+ */
+static pthread_once_t strerror_buf_key_once = PTHREAD_ONCE_INIT;
+
+/**
+ * Create the key used for the thread-specific error buffer
+ */
+static void create_strerror_buf_key()
+{
+	pthread_key_create(&strerror_buf_key, free);
+}
+
+/**
+ * Retrieve the error buffer assigned to the current thread (or create it)
+ */
+static inline char *get_strerror_buf()
+{
+	char *buf;
+
+	pthread_once(&strerror_buf_key_once, create_strerror_buf_key);
+	buf = pthread_getspecific(strerror_buf_key);
+	if (!buf)
+	{
+		buf = malloc(STRERROR_BUF_LEN);
+		pthread_setspecific(strerror_buf_key, buf);
+	}
+	return buf;
+}
+
+#ifdef HAVE_STRERROR_R
+/*
+ * Described in header.
+ */
+const char *strerror_safe(int errnum)
+{
+	char *buf = get_strerror_buf(), *msg;
+
+#ifdef STRERROR_R_CHAR_P
+	/* char* version which may or may not return the original buffer */
+	msg = strerror_r(errnum, buf, STRERROR_BUF_LEN);
+#else
+	/* int version returns 0 on success */
+	msg = strerror_r(errnum, buf, STRERROR_BUF_LEN) ? "Unknown error" : buf;
+#endif
+	return msg;
+}
+#else /* HAVE_STRERROR_R */
+/* we actually wan't to call strerror(3) below */
+#undef strerror
+/*
+ * Described in header.
+ */
+const char *strerror_safe(int errnum)
+{
+	static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+	char *buf = get_strerror_buf();
+
+	/* use a mutex to ensure calling strerror(3) is thread-safe */
+	pthread_mutex_lock(&mutex);
+	strncpy(buf, strerror(errnum), STRERROR_BUF_LEN);
+	pthread_mutex_unlock(&mutex);
+	buf[STRERROR_BUF_LEN - 1] = '\0';
+	return buf;
+}
+#endif /* HAVE_STRERROR_R */

src/libstrongswan/utils/utils/strerror.h

@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2012-2014 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * 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.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * 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.
+ */
+
+/**
+ * @{ @ingroup utils
+ */
+
+#ifndef STRERROR_H_
+#define STRERROR_H_
+
+/**
+ * Thread-safe wrapper around strerror and strerror_r.
+ *
+ * This is required because the first is not thread-safe (on some platforms)
+ * and the second uses two different signatures (POSIX/GNU) and is impractical
+ * to use anyway.
+ *
+ * @param errnum	error code (i.e. errno)
+ * @return			error message
+ */
+const char *strerror_safe(int errnum);
+
+/**
+ * Replace usages of strerror(3) with thread-safe variant.
+ */
+#define strerror(errnum) strerror_safe(errnum)
+
+#endif /** STRERROR_H_ @}*/