dtls_prng_posix.c: Fix random() only support

Use of random() requires that _GNU_SOURCE is defined. Cannot use variables named rand. Make sure that dtls_prng.o is rebuilt whenever any of the platform-specific/dtls_prng_*.c files are updated. Signed-off-by: Jon Shallow <[email protected]>
eclipse · Apr 24, 2023 · a5fa982 · a5fa982
1 parent 11c8e7d
commit a5fa982
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Showing 2 changed files with 12 additions and 4 deletions.
diff --git a/Makefile.in b/Makefile.in
@@ -85,6 +85,8 @@ dirs:	$(SUBDIRS)
 		$(MAKE) -C $$dir ; \
 	done
 
+dtls_prng.o::	$(wildcard platform-specific/dtls_prng_*.c)
+
 $(SUB_OBJECTS)::
 	$(MAKE) -C $(@D) $(@F)
 

diff --git a/platform-specific/dtls_prng_posix.c b/platform-specific/dtls_prng_posix.c
@@ -18,6 +18,12 @@
  *
  *******************************************************************************/
 
+#ifdef HAVE_RANDOM
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif /* _GNU_SOURCE */
+#endif /* HAVE_RANDOM */
+
 #include "tinydtls.h"
 #include "dtls_prng.h"
 #include "dtls_debug.h"
@@ -44,16 +50,16 @@ dtls_prng(unsigned char *buf, size_t len) {
   if (len) {
     size_t klen = len;
     uint8_t byte_counter = RAND_BYTES;
-    uint32_t rand = random();
+    uint32_t rand_val = random();
     while (1) {
-      *buf++ = rand & 0xFF;
+      *buf++ = rand_val & 0xFF;
       if (!--klen) {
         break;
       }
       if (--byte_counter) {
-        rand >>= 8;
+        rand_val >>= 8;
       } else {
-        rand = random();
+        rand_val = random();
         byte_counter = RAND_BYTES;
       }
     }