[Suspend2][ 08/28] [Suspend2] Parse swapwriter signature.

[Nigel Cunningham <nigel@suspend2.net>]

Parse a signature. It may reflect a normal swapheader of type 1 or 2, a
swsusp header or a Suspend2 header.

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

 kernel/power/suspend_swap.c |   50 +++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 50 insertions(+), 0 deletions(-)

diff --git a/kernel/power/suspend_swap.c b/kernel/power/suspend_swap.c
index a014103..08c4f86 100644
--- a/kernel/power/suspend_swap.c
+++ b/kernel/power/suspend_swap.c
@@ -243,3 +243,53 @@ static void swapwriter_noresume_reset(vo
 	close_bdevs();
 }
 
+static int parse_signature(char *header, int restore)
+{
+	int type = -1;
+	
+	if (!memcmp("SWAP-SPACE",header,10))
+		return 0;
+	else if (!memcmp("SWAPSPACE2",header,10))
+		return 1;
+
+	else if (!memcmp("S1SUSP",header,6))
+		type = 4;
+	else if (!memcmp("S2SUSP",header,6))
+		type = 5;
+	
+	else if (!memcmp("z",header,1))
+		type = 12;
+	else if (!memcmp("Z",header,1))
+		type = 13;
+	
+	/* 
+	 * Put bdev of suspend header in last byte of swap header
+	 * (unsigned short)
+	 */
+	if (type > 11) {
+		dev_t *header_ptr = (dev_t *) &header[1];
+		unsigned char *headerblocksize_ptr =
+			(unsigned char *) &header[5];
+		u32 *headerblock_ptr = (u32 *) &header[6];
+		header_dev_t = *header_ptr;
+		/* 
+		 * We are now using the highest bit of the char to indicate
+		 * whether we have attempted to resume from this image before.
+		 */
+		clear_suspend_state(SUSPEND_RESUMED_BEFORE);
+		if (((int) *headerblocksize_ptr) & 0x80)
+			set_suspend_state(SUSPEND_RESUMED_BEFORE);
+		headerblock = (unsigned long) *headerblock_ptr;
+	}
+
+	if ((restore) && (type > 5)) {
+		/* We only reset our own signatures */
+		if (type & 1)
+			memcpy(header,"SWAPSPACE2",10);
+		else
+			memcpy(header,"SWAP-SPACE",10);
+	}
+
+	return type;
+}
+

--
Nigel Cunningham		nigel at suspend2 dot net