initial top-level import of subdirectories

crypto/compat/issetugid_linux.c

@@ -0,0 +1,47 @@
+/*
+ * issetugid implementation for Linux
+ * Public domain
+ */
+
+#include <errno.h>
+#include <gnu/libc-version.h>
+#include <string.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+/*
+ * Linux-specific glibc 2.16+ interface for determining if a process was
+ * launched setuid/setgid or with additional capabilities.
+ */
+#ifdef HAVE_GETAUXVAL
+#include <sys/auxv.h>
+#endif
+
+int issetugid(void)
+{
+#ifdef HAVE_GETAUXVAL
+	/*
+	 * The API for glibc < 2.19 does not indicate if there is an error with
+	 * getauxval. While it should not be the case that any 2.6 or greater
+	 * kernel ever does not supply AT_SECURE, an emulated software environment
+	 * might rewrite the aux vector.
+	 *
+	 * See https://sourceware.org/bugzilla/show_bug.cgi?id=15846
+	 *
+	 * Perhaps this code should just read the aux vector itself, so we have
+	 * backward-compatibility and error handling in older glibc versions.
+	 * info: http://lwn.net/Articles/519085/
+	 *
+	 */
+	const char *glcv = gnu_get_libc_version();
+	if (strverscmp(glcv, "2.19") >= 0) {
+		errno = 0;
+		if (getauxval(AT_SECURE) == 0) {
+			if (errno != ENOENT) {
+				return 0;
+			}
+		}
+	}
+#endif
+	return 1;
+}

crypto/compat/thread_private.h

@@ -0,0 +1,6 @@
+#include <pthread.h>
+
+static pthread_mutex_t arc4random_mtx = PTHREAD_MUTEX_INITIALIZER;
+
+#define _ARC4_LOCK()   pthread_mutex_lock(&arc4random_mtx)
+#define _ARC4_UNLOCK() pthread_mutex_unlock(&arc4random_mtx)