From dcf889cb72d2d385db03e3ee29b80fbf035abf69 Mon Sep 17 00:00:00 2001
From: Roy Marples <roy@marples.name>
Date: Thu, 15 May 2008 19:21:15 +0000
Subject: [PATCH] Use arc4random as everything apart from glibc seems to have
 it.

---
 client.c | 10 +++++-----
 common.c | 20 --------------------
 common.h | 13 +++++--------
 dhcpcd.c | 23 ++++++++++++++++++++++-
 4 files changed, 32 insertions(+), 34 deletions(-)

diff --git a/client.c b/client.c
index 7208675c..dca85e87 100644
--- a/client.c
+++ b/client.c
@@ -307,7 +307,7 @@ ipv4ll_get_address(struct interface *iface, struct dhcp_lease *lease) {
 
 	for (;;) {
 		addr.s_addr = htonl(LINKLOCAL_ADDR |
-				    (((uint32_t)abs((int)random())
+				    (((uint32_t)abs((int)arc4random())
 				      % 0xFD00) + 0x0100));
 		errno = 0;
 		if (!arp_claim(iface, addr))
@@ -786,7 +786,7 @@ handle_signal(int sig, struct if_state *state,  const struct options *options)
 		logger (LOG_INFO, "received SIGHUP, releasing lease");
 		if (!IN_LINKLOCAL(ntohl(lease->addr.s_addr))) {
 			do_socket(state, SOCKET_OPEN);
-			state->xid = (uint32_t)random();
+			state->xid = arc4random();
 			send_message(state, DHCP_RELEASE, options);
 			do_socket(state, SOCKET_CLOSED);
 		}
@@ -887,7 +887,7 @@ handle_timeout(struct if_state *state, const struct options *options)
 
 	switch (state->state) {
 	case STATE_INIT:
-		state->xid = (uint32_t) random ();
+		state->xid = arc4random();
 		do_socket(state, SOCKET_OPEN);
 		state->timeout = options->timeout;
 		iface->start_uptime = uptime ();
@@ -917,7 +917,7 @@ handle_timeout(struct if_state *state, const struct options *options)
 			break;
 		}
 		state->state = STATE_RENEWING;
-		state->xid = (uint32_t)random();
+		state->xid = arc4random();
 		/* FALLTHROUGH */
 	case STATE_RENEWING:
 		iface->start_uptime = uptime();
@@ -932,7 +932,7 @@ handle_timeout(struct if_state *state, const struct options *options)
 		lease->addr.s_addr = 0;
 		do_socket(state, SOCKET_OPEN);
 		if (state->xid == 0)
-			state->xid = (uint32_t)random();
+			state->xid = arc4random();
 		lease->server.s_addr = 0;
 		send_message(state, DHCP_REQUEST, options);
 		state->timeout = lease->leasetime - lease->rebindtime;
diff --git a/common.c b/common.c
index 84429449..e207258e 100644
--- a/common.c
+++ b/common.c
@@ -36,7 +36,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <time.h>
 #include <unistd.h>
 
 #include "common.h"
@@ -75,25 +74,6 @@ get_line(char **line, size_t *len, FILE *fp)
 	return last;
 }
 
-/* OK, this should be in dhcpcd.c
- * It's here to make dhcpcd more readable */
-#if HAVE_SRANDOMDEV
-#else
-void srandomdev(void)
-{
-	int fd;
-	unsigned long seed;
-
-	fd = open("/dev/urandom", 0);
-	if (fd == -1 || read(fd,  &seed, sizeof(seed)) == -1)
-		seed = time(0);
-	if (fd >= 0)
-		close(fd);
-
-	srandom(seed);
-}
-#endif
-
 /* strlcpy is nice, shame glibc does not define it */
 #if HAVE_STRLCPY
 #else
diff --git a/common.h b/common.h
index f1105321..41918467 100644
--- a/common.h
+++ b/common.h
@@ -29,6 +29,7 @@
 #define COMMON_H
 
 /* string.h pulls in features.h so the below define checks work */
+#include <sys/cdefs.h>
 #include <sys/types.h>
 #include <sys/time.h>
 #include <stdio.h>
@@ -40,6 +41,10 @@
 # define _unused
 #endif
 
+#ifdef __GLIBC__
+#define arc4random (uint32_t)random
+#endif
+
 #ifndef HAVE_STRLCPY
 #  define HAVE_STRLCPY 1
 #endif
@@ -51,14 +56,6 @@ size_t strlcpy(char *, const char *, size_t);
 #  endif
 #endif
 
-#ifndef HAVE_SRANDOMDEV
-#  define HAVE_SRANDOMDEV 1
-#endif
-#if defined(__GLIBC__) || defined(__NetBSD__)
-#  undef HAVE_SRANDOMDEV
-void srandomdev(void);
-#endif
-
 #ifndef HAVE_CLOSEFROM
 #define HAVE_CLOSEFROM 1
 #endif
diff --git a/dhcpcd.c b/dhcpcd.c
index 435c99b6..4f2725bf 100644
--- a/dhcpcd.c
+++ b/dhcpcd.c
@@ -40,6 +40,9 @@ const char copyright[] = "Copyright (c) 2006-2008 Roy Marples";
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#ifdef __GLIBC__
+#  include <time.h> /* for srandomdev */
+#endif
 #include <unistd.h>
 
 #include "config.h"
@@ -133,6 +136,22 @@ atoint(const char *s)
 	return (int)n;
 }
 
+#ifdef __GLIBC__
+static void srandomdev(void)
+{
+	int fd;
+	unsigned long seed;
+
+	fd = open("/dev/urandom", 0);
+	if (fd == -1 || read(fd,  &seed, sizeof(seed)) == -1)
+		seed = time(0);
+	if (fd >= 0)
+		close(fd);
+
+	srandom(seed);
+}
+#endif
+
 static pid_t
 read_pid(const char *pidfile)
 {
@@ -770,8 +789,10 @@ main(int argc, char **argv)
 		logger(LOG_INFO, PACKAGE " " VERSION " starting");
 	}
 
-	/* Seed random */
+#ifdef __GLIBC__
+	/* We need to seed random for our fake arc4random call */
 	srandomdev();
+#endif
 
 #ifdef __linux__
 	/* Massage our filters per platform */
-- 
2.47.3