From ba61f84874c2c0b93552c69f778a6652b1f33403 Mon Sep 17 00:00:00 2001
From: Alasdair Kergon <agk@redhat.com>
Date: Mon, 24 May 2010 23:11:34 +0000
Subject: [PATCH] Replace strncmp kernel version number checks with proper ones

---
 WHATS_NEW             | 1 +
 lib/mirror/mirrored.c | 6 ++++--
 lib/misc/util.h       | 2 ++
 libdm/libdm-deptree.c | 9 ++++-----
 4 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/WHATS_NEW b/WHATS_NEW
index 3b02d7dff..e1cf308cb 100644
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,5 +1,6 @@
 Version 2.02.67 -
 ===============================
+  Replace strncmp kernel version number checks with proper ones.
   Avoid selecting names under /dev/block if there is an alternative.
   Update clustered log kernel module name to log-userspace for 2.6.31 onwards.
   Activate only first head of Replicator for vgchange -ay.
diff --git a/lib/mirror/mirrored.c b/lib/mirror/mirrored.c
index ff15b73aa..eca037763 100644
--- a/lib/mirror/mirrored.c
+++ b/lib/mirror/mirrored.c
@@ -474,6 +474,7 @@ static int _mirrored_target_present(struct cmd_context *cmd,
 	unsigned maj2, min2, patchlevel2;
 	char vsn[80];
 	struct utsname uts;
+	unsigned kmaj, kmin, krel;
 
 	if (!_mirrored_checked) {
 		_mirrored_present = target_present(cmd, "mirror", 1);
@@ -511,8 +512,9 @@ static int _mirrored_target_present(struct cmd_context *cmd,
 			 * The dm-log-userspace module was added to the
 			 * 2.6.31 kernel.
 			 */
-			/* FIXME Replace the broken string comparison! */
-			if (!uname(&uts) && strncmp(uts.release, "2.6.31", 6) < 0) {
+			if (!uname(&uts) &&
+			    (sscanf(uts.release, "%u.%u.%u", &kmaj, &kmin, &krel) == 3) &&
+			    KERNEL_VERSION(kmaj, kmin, krel) < KERNEL_VERSION(2, 6, 31)) {
 				if (module_present(cmd, "log-clustered"))
 					_mirror_attributes |= MIRROR_LOG_CLUSTERED;
 			} else if (module_present(cmd, "log-userspace"))
diff --git a/lib/misc/util.h b/lib/misc/util.h
index 15d2662a9..fcda36911 100644
--- a/lib/misc/util.h
+++ b/lib/misc/util.h
@@ -27,4 +27,6 @@
 
 #define uninitialized_var(x) x = x
 
+#define KERNEL_VERSION(major, minor, release) (((major) << 16) + ((minor) << 8) + (release))
+
 #endif
diff --git a/libdm/libdm-deptree.c b/libdm/libdm-deptree.c
index 21aa79462..b75e6afae 100644
--- a/libdm/libdm-deptree.c
+++ b/libdm/libdm-deptree.c
@@ -1540,9 +1540,9 @@ static int _mirror_emit_segment_line(struct dm_task *dmt, uint32_t major,
 	int pos = 0;
 	char logbuf[DM_FORMAT_DEV_BUFSIZE];
 	const char *logtype;
+	unsigned kmaj, kmin, krel;
 
-	r = uname(&uts);
-	if (r)
+	if (!uname(&uts) || sscanf(uts.release, "%u.%u.%u", &kmaj, &kmin, &krel) != 3)
 		return_0;
 
 	if ((seg->flags & DM_BLOCK_ON_ERROR)) {
@@ -1556,7 +1556,7 @@ static int _mirror_emit_segment_line(struct dm_task *dmt, uint32_t major,
 		 * "handle_errors" by the dm-mirror module's version
 		 * number (>= 1.12) or by the kernel version (>= 2.6.22).
 		 */
-		if (strncmp(uts.release, "2.6.22", 6) >= 0)
+		if (KERNEL_VERSION(kmaj, kmin, krel) >= KERNEL_VERSION(2, 6, 22))
 			handle_errors = 1;
 		else
 			block_on_error = 1;
@@ -1575,8 +1575,7 @@ static int _mirror_emit_segment_line(struct dm_task *dmt, uint32_t major,
 		 * The dm-log-userspace module was added to the
 		 * 2.6.31 kernel.
 		 */
-		/* FIXME Replace the broken string comparison! */
-		if (strncmp(uts.release, "2.6.31", 6) >= 0)
+		if (KERNEL_VERSION(kmaj, kmin, krel) >= KERNEL_VERSION(2, 6, 31))
 			dm_log_userspace = 1;
 	}
 
-- 
2.43.5