From: Josua Mayer <josua.maye...@gmail.com>
This change adds code to handle a new option on cmdline: overlay=
This is used to find the rootfs_data partition / disk when it has a
non-standard name or location.
It takes either the device node name, or the partition name:
i.e. /dev/mmcblk0p3, mmcblk0p3, rootfs_data
This option has precedence over the default name "rootfs_data", and extroot.
Signed-off-by: Josua Mayer <josua.maye...@gmail.com>.
---
libfstools/ext4.c | 4 +--
mount_root.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
2 files changed, 90 insertions(+), 4 deletions(-)
diff --git a/libfstools/ext4.c b/libfstools/ext4.c
index f648aa8..2c6dd91 100644
--- a/libfstools/ext4.c
+++ b/libfstools/ext4.c
@@ -77,8 +77,8 @@ ext4_part_match(char *dev, char *name, char *filename)
strcpy(devname, buf + strlen("DEVNAME="));
continue;
}
- /* Match partition name */
- if (strstr(buf, name)) {
+ /* Match either partition name or device node name */
+ if (strstr(buf, name) || strstr(devname, name)) {
ret = 0;
break;
}
diff --git a/mount_root.c b/mount_root.c
index 47a3409..9bc3356 100644
--- a/mount_root.c
+++ b/mount_root.c
@@ -28,11 +28,56 @@ static int
start(int argc, char *argv[1])
{
struct volume *root;
- struct volume *data = volume_find("rootfs_data");
+ struct volume *data = NULL;
if (!getenv("PREINIT"))
return -1;
+ /*
+ * Check cmdline for a hint about overlay device
+ * e.g. /dev/mmcblk0p3
+ */
+ {
+ FILE *fp;
+ struct stat fs = {0};
+ char *buffer;
+
+ fp = fopen("/proc/cmdline", "r");
+ fstat(fileno(fp), &fs);
+ buffer = calloc(1, fs.st_size+1);
+ while (!feof(fp)) {
+ if(fscanf(fp, "overlay=%s", buffer))
+ break;
+
+ fseek(fp, 1, SEEK_CUR);
+ }
+ fclose(fp);
+
+ /*
+ * If an overlay= argument was found, look for a volume with
that name
+ */
+ if (buffer[0]) {
+ /*
+ * strip /dev/ prefix if any
+ */
+ int offset = 0;
+ if (strstr(buffer, "/dev/"))
+ offset = 5;
+
+ ULOG_NOTE("Looking for overlay device given on
commandline\n");
+ data = volume_find(buffer + offset);
+ }
+ free(buffer);
+ }
+
+ /*
+ * Look for default rootfs_data partition name
+ */
+ data = volume_find("rootfs_data");
+
+ /*
+ * In case rootfs_data doesn't exist, only mount /dev/root for now
+ */
if (!data) {
root = volume_find("rootfs");
volume_init(root);
@@ -95,8 +140,49 @@ stop(int argc, char *argv[1])
static int
done(int argc, char *argv[1])
{
- struct volume *v = volume_find("rootfs_data");
+ struct volume *v = NULL;
+ FILE *fp;
+ struct stat fs = {0};
+ char *buffer;
+ /*
+ * First check if there is an overlay device hint in cmdline
+ */
+ fp = fopen("/proc/cmdline", "r");
+ fstat(fileno(fp), &fs);
+ buffer = calloc(1, fs.st_size+1);
+ while (!feof(fp)) {
+ if (fscanf(fp, "overlay=%s", buffer))
+ break;
+
+ fseek(fp, 1, SEEK_CUR);
+ }
+ fclose(fp);
+
+ /*
+ * If an overlay= argument was found, look for a volume with that name
+ */
+ if (buffer[0]) {
+ /*
+ * strip /dev/ prefix if any
+ */
+ int offset = 0;
+ if (strstr(buffer, "/dev/"))
+ offset = 5;
+
+ v = volume_find(buffer + offset);
+ }
+ free(buffer);
+
+ /*
+ * Now look for standard overlay partition name
+ */
+ if (!v)
+ v = volume_find("rootfs_data");
+
+ /*
+ * If no overlay device exists, then there is nothing to do here
+ */
if (!v)
return -1;
--
2.6.6
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