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Subject[Suspend2][ 30/35] [Suspend2] Filewriter parse resume2 parameter.
Date
Parse a resume2= value to see if it is for the filewriter's use (file:
prefix or filewriter is the only writer registered), and whether it points
to a device we can open and a header we recognise.

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

kernel/power/suspend_file.c | 116 +++++++++++++++++++++++++++++++++++++++++++
1 files changed, 116 insertions(+), 0 deletions(-)
diff --git a/kernel/power/suspend_file.c b/kernel/power/suspend_file.c
index 56de7d9..ee371ce 100644
--- a/kernel/power/suspend_file.c
+++ b/kernel/power/suspend_file.c
@@ -872,3 +872,119 @@ static void test_filewriter_target(void)
setting_filewriter_target = 0;
}

+/*
+ * Parse Image Location
+ *
+ * Attempt to parse a resume2= parameter.
+ * Swap Writer accepts:
+ * resume2=file:DEVNAME[:FIRSTBLOCK]
+ *
+ * Where:
+ * DEVNAME is convertable to a dev_t by name_to_dev_t
+ * FIRSTBLOCK is the location of the first block in the file.
+ * BLOCKSIZE is the logical blocksize >= SECTOR_SIZE & <= PAGE_SIZE,
+ * mod SECTOR_SIZE == 0 of the device.
+ * Data is validated by attempting to read a header from the
+ * location given. Failure will result in filewriter refusing to
+ * save an image, and a reboot with correct parameters will be
+ * necessary.
+ */
+
+static int filewriter_parse_sig_location(char *commandline, int only_writer)
+{
+ char *thischar, *devstart = NULL, *colon = NULL, *at_symbol = NULL;
+ int result = -EINVAL, target_blocksize = 0;
+
+ if (strncmp(commandline, "file:", 5)) {
+ if (!only_writer)
+ return 1;
+ } else
+ commandline += 5;
+
+ /*
+ * Don't check signature again if we're beginning a cycle. If we already
+ * did the initialisation successfully, assume we'll be okay when it comes
+ * to resuming.
+ */
+ if (filewriter_target_bdev)
+ return 0;
+
+ devstart = thischar = commandline;
+ while ((*thischar != ':') && (*thischar != '@') &&
+ ((thischar - commandline) < 250) && (*thischar))
+ thischar++;
+
+ if (*thischar == ':') {
+ colon = thischar;
+ *colon = 0;
+ thischar++;
+ }
+
+ while ((*thischar != '@') && ((thischar - commandline) < 250) && (*thischar))
+ thischar++;
+
+ if (*thischar == '@') {
+ at_symbol = thischar;
+ *at_symbol = 0;
+ }
+
+ /*
+ * For the filewriter, you can be able to resume, but not suspend,
+ * because the resume2= is set correctly, but the filewriter_target
+ * isn't.
+ *
+ * We may have come here as a result of setting resume2 or
+ * filewriter_target. We only test the filewriter target in the
+ * former case (it's already done in the later), and we do it before
+ * setting the block number ourselves. It will overwrite the values
+ * given on the command line if we don't.
+ */
+
+ if (!setting_filewriter_target)
+ __test_filewriter_target(filewriter_target, 1);
+
+ if (colon)
+ target_firstblock = (int) simple_strtoul(colon + 1, NULL, 0);
+ else
+ target_firstblock = 0;
+
+ if (at_symbol) {
+ target_blocksize = (int) simple_strtoul(at_symbol + 1, NULL, 0);
+ if (target_blocksize & (SECTOR_SIZE - 1)) {
+ printk("Filewriter: Blocksizes are multiples of %d.\n", SECTOR_SIZE);
+ result = -EINVAL;
+ goto out;
+ }
+ }
+
+ printk("Suspend2 Filewriter: Testing whether you can resume:\n");
+
+ filewriter_get_target_info(commandline, 0, 1);
+
+ if (!filewriter_target_bdev || IS_ERR(filewriter_target_bdev)) {
+ filewriter_target_bdev = NULL;
+ result = -1;
+ goto out;
+ }
+
+ if (target_blocksize)
+ set_devinfo(filewriter_target_bdev, ffs(target_blocksize));
+
+ result = __test_filewriter_target(commandline, 1);
+
+out:
+ if (result)
+ clear_suspend_state(SUSPEND_CAN_SUSPEND);
+ else
+ set_suspend_state(SUSPEND_CAN_SUSPEND);
+
+ printk("Resuming %sabled.\n", result ? "dis" : "en");
+
+ if (colon)
+ *colon = ':';
+ if (at_symbol)
+ *at_symbol = '@';
+
+ return result;
+}
+
--
Nigel Cunningham nigel at suspend2 dot net
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