Merge pull request #59 from michaelolbrich/autoresize

hdimge: allow the last partition to fill the rest of the image

3 files changed, 57 insertions, 31 deletions

diff --git a/README.rst b/README.rst
index 67a648a..92ae9e8 100644
--- a/README.rst
+++ b/README.rst
@@ -89,12 +89,16 @@ Partition options:
 
 :offset:		The offset of this partition as a total offset to the beginning
 			of the device.
-:size:			The size of this partition in bytes. The last partition may have
-			size 0 to make this partition use the rest of the available space
-			on the device.
+:size:			The size of this partition in bytes. If the size and
+			autoresize are both not set then the size of the partition
+			image is used.
 :partition-type:	Used by dos partition tables to specify the partition type.
 :image:			The image file this partition shall be filled with
-:autoresize:		used by ubi (FIXME: do we need this? Isn't size = 0 enough)
+:autoresize:		Boolean specifying that the partition should be resized
+			automatically. For UBI volumes this means that the
+			``autoresize`` flag is set. Only one volume can have this flag.
+			For hd images this can be used for the last partition. If set
+			the partition will fill the remaining space of the image.
 :bootable:		Boolean specifying whether to set the bootable flag.
 :in-partition-table:	Boolean specifying whether to include this partition in
 			the partition table.
diff --git a/image-hd.c b/image-hd.c
index 1f80ae7..90f550e 100644
--- a/image-hd.c
+++ b/image-hd.c
@@ -404,7 +404,7 @@ static unsigned long long roundup(unsigned long long value, unsigned long long a
 static int hdimage_setup(struct image *image, cfg_t *cfg)
 {
 	struct partition *part;
-	int has_extended;
+	int has_extended, autoresize = 0;
 	unsigned int partition_table_entries = 0;
 	unsigned long long now = 0;
 	struct hdimage *hd = xzalloc(sizeof(*hd));
@@ -448,33 +448,15 @@ static int hdimage_setup(struct image *image, cfg_t *cfg)
 
 	partition_table_entries = 0;
 	list_for_each_entry(part, &image->partitions, list) {
-		if (part->image) {
-			struct image *child = image_get(part->image);
-			if (!child) {
-				image_error(image, "could not find %s\n",
-						part->image);
-				return -EINVAL;
-			}
-			if (!part->size) {
-				if (part->in_partition_table)
-					part->size = roundup(child->size, hd->align);
-				else
-					part->size = child->size;
-			} else if (child->size > part->size) {
-				image_error(image, "part %s size (%lld) too small for %s (%lld)\n",
-						part->name, part->size, child->file, child->size);
-				return -EINVAL;
-			}
-		}
-		if (!part->size) {
-			image_error(image, "part %s size must not be zero\n",
-					part->name);
+		if (autoresize) {
+			image_error(image, "'autoresize' is only supported "
+					"for the last partition\n");
 			return -EINVAL;
 		}
-		if (part->in_partition_table && (part->size % 512)) {
-			image_error(image, "part %s size (%lld) must be a "
-					"multiple of 1 sector (512 bytes)\n",
-					part->name, part->size);
+		autoresize = part->autoresize;
+		if (autoresize && image->size == 0) {
+			image_error(image, "the images size must be specified "
+					"when using a 'autoresize' partition\n");
 			return -EINVAL;
 		}
 		if (hd->gpt) {
@@ -538,6 +520,45 @@ static int hdimage_setup(struct image *image, cfg_t *cfg)
 			}
 			part->offset = roundup(now, hd->align);
 		}
+		if (autoresize) {
+			long long partsize = image->size - now;
+			if (hd->gpt)
+				partsize -= GPT_SECTORS * 512;
+			if (partsize < 0) {
+				image_error(image, "partitions exceed device size\n");
+				return -EINVAL;
+			}
+			part->size = partsize;
+		}
+		if (part->image) {
+			struct image *child = image_get(part->image);
+			if (!child) {
+				image_error(image, "could not find %s\n",
+						part->image);
+				return -EINVAL;
+			}
+			if (!part->size) {
+				if (part->in_partition_table)
+					part->size = roundup(child->size, hd->align);
+				else
+					part->size = child->size;
+			} else if (child->size > part->size) {
+				image_error(image, "part %s size (%lld) too small for %s (%lld)\n",
+						part->name, part->size, child->file, child->size);
+				return -EINVAL;
+			}
+		}
+		if (!part->size) {
+			image_error(image, "part %s size must not be zero\n",
+					part->name);
+			return -EINVAL;
+		}
+		if (part->in_partition_table && (part->size % 512)) {
+			image_error(image, "part %s size (%lld) must be a "
+					"multiple of 1 sector (512 bytes)\n",
+					part->name, part->size);
+			return -EINVAL;
+		}
 		now = part->offset + part->size;
 	}
 
diff --git a/test/hdimage.config b/test/hdimage.config
index 7287b6d..117e69f 100644
--- a/test/hdimage.config
+++ b/test/hdimage.config
@@ -68,7 +68,8 @@ image test.hdimage-2 {
 	}
 	partition part6 {
 		image = "part2.img"
-		size = 1M
+		autoresize = true
 		partition-type = 0x83
 	}
+	size = 12M
 }