From c544aa2c25095e6a4d4fca761eb15c46435086fc Mon Sep 17 00:00:00 2001
From: Petr Uzel
Date: Sun, 6 May 2012 21:55:53 +0200
Subject: libuuid: avoid double open and leaking fd (reworked)

This reverts commit 6126f7a53c57485a9a29ddd772765695f23c92e6
and fixes the double open and leaking descriptor in a different way,
that is by using newly introduced function 'have_random_source()'
to check whether good random source is available while deciding
which uuid type to generate (random/time).

This is better than calling random_get_fd() twice, passing the file
descriptor down the stack and reusing it in next call to
random_get_fd().

Signed-off-by: Petr Uzel <petr.uzel@suse.cz>
---
 libuuid/src/gen_uuid.c | 28 ++++++++++++++++++----------
 libuuid/src/uuidd.h    |  2 +-
 2 files changed, 19 insertions(+), 11 deletions(-)

(limited to 'libuuid')

diff --git a/libuuid/src/gen_uuid.c b/libuuid/src/gen_uuid.c
index 76f1bbdad..93d292a22 100644
--- a/libuuid/src/gen_uuid.c
+++ b/libuuid/src/gen_uuid.c
@@ -277,7 +277,7 @@ static int get_clock(uint32_t *clock_high, uint32_t *clock_low,
 	}
 
 	if ((last.tv_sec == 0) && (last.tv_usec == 0)) {
-		random_get_bytes(&clock_seq, sizeof(clock_seq), -1);
+		random_get_bytes(&clock_seq, sizeof(clock_seq));
 		clock_seq &= 0x3FFF;
 		gettimeofday(&last, 0);
 		last.tv_sec--;
@@ -434,7 +434,7 @@ int __uuid_generate_time(uuid_t out, int *num)
 
 	if (!has_init) {
 		if (get_node_id(node_id) <= 0) {
-			random_get_bytes(node_id, 6, -1);
+			random_get_bytes(node_id, 6);
 			/*
 			 * Set multicast bit, to prevent conflicts
 			 * with IEEE 802 addresses obtained from
@@ -520,7 +520,7 @@ int uuid_generate_time_safe(uuid_t out)
 }
 
 
-void __uuid_generate_random(uuid_t out, int *num, int fd)
+void __uuid_generate_random(uuid_t out, int *num)
 {
 	uuid_t	buf;
 	struct uuid uu;
@@ -532,7 +532,7 @@ void __uuid_generate_random(uuid_t out, int *num, int fd)
 		n = *num;
 
 	for (i = 0; i < n; i++) {
-		random_get_bytes(buf, sizeof(buf), fd);
+		random_get_bytes(buf, sizeof(buf));
 		uuid_unpack(buf, &uu);
 
 		uu.clock_seq = (uu.clock_seq & 0x3FFF) | 0x8000;
@@ -548,7 +548,18 @@ void uuid_generate_random(uuid_t out)
 	int	num = 1;
 	/* No real reason to use the daemon for random uuid's -- yet */
 
-	__uuid_generate_random(out, &num, -1);
+	__uuid_generate_random(out, &num);
+}
+
+/*
+ * Check whether good random source (/dev/random or /dev/urandom)
+ * is available.
+ */
+static int have_random_source(void)
+{
+	struct stat s;
+
+	return (!stat("/dev/random", &s) || !stat("/dev/urandom", &s));
 }
 
 
@@ -560,11 +571,8 @@ void uuid_generate_random(uuid_t out)
  */
 void uuid_generate(uuid_t out)
 {
-	int	fd;
-	int	num = 1;
-
-	if ((fd = random_get_fd()) >= 0)
-		__uuid_generate_random(out, &num, fd);
+	if (have_random_source())
+		uuid_generate_random(out);
 	else
 		uuid_generate_time(out);
 }
diff --git a/libuuid/src/uuidd.h b/libuuid/src/uuidd.h
index 2e19522df..27b79c216 100644
--- a/libuuid/src/uuidd.h
+++ b/libuuid/src/uuidd.h
@@ -49,6 +49,6 @@
 #define UUIDD_MAX_OP			UUIDD_OP_BULK_RANDOM_UUID
 
 extern int __uuid_generate_time(uuid_t out, int *num);
-extern void __uuid_generate_random(uuid_t out, int *num, int fd);
+extern void __uuid_generate_random(uuid_t out, int *num);
 
 #endif /* _UUID_UUID_H */
-- 
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