[Suspend2][ 14/19] [Suspend2] Sanity check image header.

[Nigel Cunningham <nigel@suspend2.net>]

Check that an image header matches the currently running kernel, and return
either a string describing the problem, or NULL.

Signed-off-by: Nigel Cunningham <nigel@suspend2.net>

 kernel/power/io.c |   39 +++++++++++++++++++++++++++++++++++++++
 1 files changed, 39 insertions(+), 0 deletions(-)

diff --git a/kernel/power/io.c b/kernel/power/io.c
index d7c48e0..8c9c284 100644
--- a/kernel/power/io.c
+++ b/kernel/power/io.c
@@ -676,3 +676,42 @@ write_image_header_abort_no_cleanup:
 	return -1;
 }
 
+/* sanity_check()
+ *
+ * Description:	Perform a few checks, seeking to ensure that the kernel being
+ * 		booted matches the one suspended. They need to match so we can
+ * 		be _sure_ things will work. It is not absolutely impossible for
+ * 		resuming from a different kernel to work, just not assured.
+ * Arguments:	Struct suspend_header. The header which was saved at suspend
+ * 		time.
+ */
+static char *sanity_check(struct suspend_header *sh)
+{
+	if (sh->version_code != LINUX_VERSION_CODE)
+		return "Incorrect kernel version.";
+	
+	if (sh->num_physpages != num_physpages)
+		return "Incorrect memory size.";
+
+	if (strncmp(sh->machine, system_utsname.machine, 65))
+		return "Incorrect machine type.";
+
+	if (strncmp(sh->version, system_utsname.version, 65))
+		return "Right kernel version but wrong build number.";
+
+	if (sh->page_size != PAGE_SIZE)
+		return "Incorrect PAGE_SIZE.";
+
+	if (!test_suspend_state(SUSPEND_IGNORE_ROOTFS)) {
+		const struct super_block *sb;
+		list_for_each_entry(sb, &super_blocks, s_list) {
+			if ((!(sb->s_flags & MS_RDONLY)) &&
+			    (sb->s_type->fs_flags & FS_REQUIRES_DEV))
+				return "Device backed fs has been mounted "
+					"rw prior to resume."; 
+		}
+	}
+
+	return 0;
+}
+

--
Nigel Cunningham		nigel at suspend2 dot net