Use glibc's getrandom() instead of syscall when glibc > 2.25.
Fixes #3432
Signed-off-by: okhowang(王沛文) <okhowang@tencent.com>
diff --git a/ChangeLog.d/getrandom.txt b/ChangeLog.d/getrandom.txt
new file mode 100644
index 0000000..87a3a6c
--- /dev/null
+++ b/ChangeLog.d/getrandom.txt
@@ -0,0 +1,2 @@
+Changes
+ Use glibc's getrandom() instead of syscall when glibc > 2.25.
diff --git a/library/entropy_poll.c b/library/entropy_poll.c
index 4bf660e..0f992f3 100644
--- a/library/entropy_poll.c
+++ b/library/entropy_poll.c
@@ -18,9 +18,15 @@
*/
#if defined(__linux__)
+#if !defined(_GNU_SOURCE)
/* Ensure that syscall() is available even when compiling with -std=c99 */
#define _GNU_SOURCE
#endif
+#include <features.h>
+#if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 25)
+#define HAVE_SYS_RANDOM 1
+#endif
+#endif
#include "common.h"
@@ -86,10 +92,16 @@
/*
* Test for Linux getrandom() support.
- * Since there is no wrapper in the libc yet, use the generic syscall wrapper
+ * When the C library is GNU libc and its version is greater than 2.25,
+ * include sys/random.h to use getrandom(),
+ * otherwise use the generic use the generic syscall wrapper
* available in GNU libc and compatible libc's (eg uClibc).
*/
-#if ((defined(__linux__) && defined(__GLIBC__)) || defined(__midipix__))
+#if HAVE_SYS_RANDOM
+#include <sys/random.h>
+#include <errno.h>
+#define HAVE_GETRANDOM
+#elif (defined(__linux__) && defined(__GLIBC__)) || defined(__midipix__)
#include <unistd.h>
#include <sys/syscall.h>
#if defined(SYS_getrandom)
@@ -155,7 +167,11 @@
((void) data);
#if defined(HAVE_GETRANDOM)
+#if HAVE_SYS_RANDOM
+ ret = getrandom(output, len, 0);
+#else
ret = getrandom_wrapper( output, len, 0 );
+#endif
if( ret >= 0 )
{
*olen = ret;