From: Jes Sorensen <Jes.Sorensen@redhat.com>
Date: Mon, 15 Aug 2016 19:41:34 +0000 (-0400)
Subject: Introduce random_uuid() helper function
X-Git-Tag: mdadm-4.0~62
X-Git-Url: http://git.ipfire.org/?p=thirdparty%2Fmdadm.git;a=commitdiff_plain;h=c5f71c2417a53e097f6556e99027b7249d116a78;hp=977d12d739deedd21ea3ca5a96d0ffd83bd5b4ea

Introduce random_uuid() helper function

This gets rid of 5 nearly identical copies of the same code, and
reduces the binary size of mdadm by over 700 bytes on x86_64.

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
---

diff --git a/Assemble.c b/Assemble.c
index d274e6e0..3da09033 100644
--- a/Assemble.c
+++ b/Assemble.c
@@ -599,18 +599,9 @@ static int load_devices(struct devs *devices, char *devmap,
 			int err;
 			fstat(mdfd, &stb2);
 
-			if (strcmp(c->update, "uuid")==0 &&
-			    !ident->uuid_set) {
-				int rfd;
-				if ((rfd = open("/dev/urandom", O_RDONLY)) < 0 ||
-				    read(rfd, ident->uuid, 16) != 16) {
-					*(__u32*)(ident->uuid) = random();
-					*(__u32*)(ident->uuid+1) = random();
-					*(__u32*)(ident->uuid+2) = random();
-					*(__u32*)(ident->uuid+3) = random();
-				}
-				if (rfd >= 0) close(rfd);
-			}
+			if (strcmp(c->update, "uuid") == 0 && !ident->uuid_set)
+				random_uuid((__u8 *)ident->uuid);
+
 			dfd = dev_open(devname,
 				       tmpdev->disposition == 'I'
 				       ? O_RDWR : (O_RDWR|O_EXCL));
diff --git a/mdadm.h b/mdadm.h
index cfa5bebe..0516c826 100755
--- a/mdadm.h
+++ b/mdadm.h
@@ -1470,6 +1470,7 @@ extern int mdmon_running(char *devnm);
 extern int mdmon_pid(char *devnm);
 extern int check_env(char *name);
 extern __u32 random32(void);
+extern void random_uuid(__u8 *buf);
 extern int start_mdmon(char *devnm);
 
 extern int child_monitor(int afd, struct mdinfo *sra, struct reshape *reshape,
diff --git a/super1.c b/super1.c
index b7974031..f3e40232 100644
--- a/super1.c
+++ b/super1.c
@@ -1175,7 +1175,7 @@ static int update_super1(struct supertype *st, struct mdinfo *info,
 		}
 	} else if (strcmp(update, "linear-grow-new") == 0) {
 		unsigned int i;
-		int rfd, fd;
+		int fd;
 		unsigned int max = __le32_to_cpu(sb->max_dev);
 
 		for (i=0 ; i < max ; i++)
@@ -1186,13 +1186,7 @@ static int update_super1(struct supertype *st, struct mdinfo *info,
 		if (max >= __le32_to_cpu(sb->max_dev))
 			sb->max_dev = __cpu_to_le32(max+1);
 
-		if ((rfd = open("/dev/urandom", O_RDONLY)) < 0 ||
-		    read(rfd, sb->device_uuid, 16) != 16) {
-			__u32 r[4] = {random(), random(), random(), random()};
-			memcpy(sb->device_uuid, r, 16);
-		}
-		if (rfd >= 0)
-			close(rfd);
+		random_uuid(sb->device_uuid);
 
 		sb->dev_roles[i] =
 			__cpu_to_le16(info->disk.raid_disk);
@@ -1407,7 +1401,6 @@ static int init_super1(struct supertype *st, mdu_array_info_t *info,
 {
 	struct mdp_superblock_1 *sb;
 	int spares;
-	int rfd;
 	char defname[10];
 	int sbsize;
 
@@ -1437,14 +1430,8 @@ static int init_super1(struct supertype *st, mdu_array_info_t *info,
 
 	if (uuid)
 		copy_uuid(sb->set_uuid, uuid, super1.swapuuid);
-	else {
-		if ((rfd = open("/dev/urandom", O_RDONLY)) < 0 ||
-		    read(rfd, sb->set_uuid, 16) != 16) {
-			__u32 r[4] = {random(), random(), random(), random()};
-			memcpy(sb->set_uuid, r, 16);
-		}
-		if (rfd >= 0) close(rfd);
-	}
+	else
+		random_uuid(sb->set_uuid);;
 
 	if (name == NULL || *name == 0) {
 		sprintf(defname, "%d", info->md_minor);
@@ -1707,7 +1694,6 @@ static int write_init_super1(struct supertype *st)
 {
 	struct mdp_superblock_1 *sb = st->sb;
 	struct supertype *refst;
-	int rfd;
 	int rv = 0;
 	unsigned long long bm_space;
 	struct devinfo *di;
@@ -1735,13 +1721,7 @@ static int write_init_super1(struct supertype *st)
 		else
 			sb->devflags &= ~WriteMostly1;
 
-		if ((rfd = open("/dev/urandom", O_RDONLY)) < 0 ||
-		    read(rfd, sb->device_uuid, 16) != 16) {
-			__u32 r[4] = {random(), random(), random(), random()};
-			memcpy(sb->device_uuid, r, 16);
-		}
-		if (rfd >= 0)
-			close(rfd);
+		random_uuid(sb->device_uuid);
 
 		if (!(di->disk.state & (1<<MD_DISK_JOURNAL)))
 			sb->events = 0;
@@ -2597,7 +2577,6 @@ void *super1_make_v0(struct supertype *st, struct mdinfo *info, mdp_super_t *sb0
 	void *ret;
 	struct mdp_superblock_1 *sb;
 	int i;
-	int rfd;
 	unsigned long long offset;
 
 	if (posix_memalign(&ret, 4096, 1024) != 0)
@@ -2629,13 +2608,7 @@ void *super1_make_v0(struct supertype *st, struct mdinfo *info, mdp_super_t *sb0
 	sb->super_offset = __cpu_to_le64(offset);
 	//*(__u64*)(st->other + 128 + 8 + 8) = __cpu_to_le64(offset);
 
-	if ((rfd = open("/dev/urandom", O_RDONLY)) < 0 ||
-	    read(rfd, sb->device_uuid, 16) != 16) {
-		__u32 r[4] = {random(), random(), random(), random()};
-		memcpy(sb->device_uuid, r, 16);
-	}
-	if (rfd >= 0)
-		close(rfd);
+	random_uuid(sb->device_uuid);
 
 	for (i = 0; i < MD_SB_DISKS; i++) {
 		int state = sb0->disks[i].state;
diff --git a/util.c b/util.c
index 9fcc4b0d..8b522423 100644
--- a/util.c
+++ b/util.c
@@ -1936,6 +1936,27 @@ __u32 random32(void)
 	return rv;
 }
 
+void random_uuid(__u8 *buf)
+{
+	int fd, i, len;
+	__u32 r[4];
+
+	fd = open("/dev/urandom", O_RDONLY);
+	if (fd < 0)
+		goto use_random;
+	len = read(fd, buf, 16);
+	close(fd);
+	if (len != 16)
+		goto use_random;
+
+	return;
+
+use_random:
+	for (i = 0; i < 4; i++)
+		r[i] = random();
+	memcpy(buf, r, 16);
+}
+
 #ifndef MDASSEMBLE
 int flush_metadata_updates(struct supertype *st)
 {