[PATCH 1/2] cdev: merge identical partitions despite DEVFS_PARTITION_CAN_OVERLAP

[PATCH 1/2] cdev: merge identical partitions despite DEVFS_PARTITION_CAN_OVERLAP

[Ahmad Fatoum]

When a partition is created that's exactly the same size and offset as
an existing partition, barebox will create the new partition as link to
the existing partition.

Maintain this behavior, even if DEVFS_PARTITION_CAN_OVERLAP is set.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 fs/devfs-core.c | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/fs/devfs-core.c b/fs/devfs-core.c
index 133fd9ec026a..c9313ed73167 100644
--- a/fs/devfs-core.c
+++ b/fs/devfs-core.c
@@ -440,7 +440,7 @@ int devfs_remove(struct cdev *cdev)
 /**
  * check_overlap() - check overlap with existing partitions
  * @cdev: parent cdev
- * @name: partition name for informational purposes on conflict
+ * @partinfo: partition information
  * @offset: offset of new partition to be added
  * @size: size of new partition to be added
  *
@@ -448,7 +448,9 @@ int devfs_remove(struct cdev *cdev)
  *         partition if and only if it's identical in offset and size
  *         to an existing partition. Otherwise, PTR_ERR(-EINVAL).
  */
-static struct cdev *check_overlap(struct cdev *cdev, const char *name, loff_t offset, loff_t size)
+static struct cdev *check_overlap(struct cdev *cdev,
+				  const struct devfs_partition *partinfo,
+				  loff_t offset, loff_t size)
 {
 	struct cdev *cpart;
 	loff_t cpart_offset;
@@ -471,6 +473,8 @@ static struct cdev *check_overlap(struct cdev *cdev, const char *name, loff_t of
 		}
 
 		if (region_overlap_size(cpart_offset, cpart->size, offset, size)) {
+			if (partinfo->flags & DEVFS_PARTITION_CAN_OVERLAP)
+				return NULL;
 			ret = -EINVAL;
 			goto conflict;
 		}
@@ -483,7 +487,7 @@ static struct cdev *check_overlap(struct cdev *cdev, const char *name, loff_t of
 	__pr_printk(ret ? MSG_WARNING : MSG_DEBUG,
 		    "New partition %s (0x%08llx-0x%08llx) on %s "
 		    "%s with partition %s (0x%08llx-0x%08llx), not creating it\n",
-		    name, offset, offset + size - 1, cdev->name,
+		    partinfo->name, offset, offset + size - 1, cdev->name,
 		    ret ? "conflicts" : "identical",
 		    cpart->name, cpart_offset, cpart_offset + cpart->size - 1);
 
@@ -530,16 +534,14 @@ static struct cdev *__devfs_add_partition(struct cdev *cdev,
 		return ERR_PTR(-EINVAL);
 	}
 
-	if (!(partinfo->flags & DEVFS_PARTITION_CAN_OVERLAP)) {
-		overlap = check_overlap(cdev, partinfo->name, offset, size);
-		if (overlap) {
-			if (!IS_ERR(overlap)) {
-				/* only fails with -EEXIST, which is fine */
-				(void)devfs_create_link(overlap, partinfo->name);
-			}
-
-			return overlap;
+	overlap = check_overlap(cdev, partinfo, offset, size);
+	if (overlap) {
+		if (!IS_ERR(overlap)) {
+			/* only fails with -EEXIST, which is fine */
+			(void)devfs_create_link(overlap, partinfo->name);
 		}
+
+		return overlap;
 	}
 
 	/* Filter flags that we want to pass along to children */
-- 
2.39.5

[PATCH 2/2] cmdlinepart: refuse partitions with empty name

[Ahmad Fatoum]

Running addpart /dev/mmc3 0xe0000@0 currently creates a partition with a
zero-sized name. Check for this condition and throw an error.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 lib/cmdlinepart.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/lib/cmdlinepart.c b/lib/cmdlinepart.c
index afba544965b4..3e8c415c7ea6 100644
--- a/lib/cmdlinepart.c
+++ b/lib/cmdlinepart.c
@@ -30,6 +30,7 @@ int cmdlinepart_do_parse_one(const char *devname, const char *partstr,
 	char *end;
 	char buf[PATH_MAX] = {};
 	unsigned long flags = DEVFS_PARTITION_FOR_FIXUP;
+	size_t partname_len = 0;
 	struct cdev *cdev;
 
 	memset(buf, 0, PATH_MAX);
@@ -60,7 +61,8 @@ int cmdlinepart_do_parse_one(const char *devname, const char *partstr,
 		if ((partition_flags & CMDLINEPART_ADD_DEVNAME) &&
 				strncmp(devname, partstr, strlen(devname)))
 			sprintf(buf, "%s.", devname);
-		memcpy(buf + strlen(buf), partstr, end - partstr);
+		partname_len = end - partstr;
+		memcpy(buf + strlen(buf), partstr, partname_len);
 
 		end++;
 	}
@@ -85,6 +87,11 @@ int cmdlinepart_do_parse_one(const char *devname, const char *partstr,
 
 	*retsize = size;
 
+	if (!partname_len) {
+		printf("partition name can't be empty\n");
+		return -EINVAL;
+	}
+
 	cdev = devfs_add_partition(devname, *offset, size, flags, buf);
 	if (IS_ERR(cdev)) {
 		printf("cannot create %s: %pe\n", buf, cdev);
-- 
2.39.5

Re: [PATCH 1/2] cdev: merge identical partitions despite DEVFS_PARTITION_CAN_OVERLAP

[Sascha Hauer]

On Sun, 16 Feb 2025 16:07:17 +0100, Ahmad Fatoum wrote:
> When a partition is created that's exactly the same size and offset as
> an existing partition, barebox will create the new partition as link to
> the existing partition.
> 
> Maintain this behavior, even if DEVFS_PARTITION_CAN_OVERLAP is set.
> 
> 
> [...]

Applied, thanks!

[1/2] cdev: merge identical partitions despite DEVFS_PARTITION_CAN_OVERLAP
      https://git.pengutronix.de/cgit/barebox/commit/?id=f7c38bec5baf (link may not be stable)
[2/2] cmdlinepart: refuse partitions with empty name
      https://git.pengutronix.de/cgit/barebox/commit/?id=1d81df84033c (link may not be stable)

Best regards,
-- 
Sascha Hauer <s.hauer@pengutronix.de>