From d6dc6766ebc3be2aa0c87b09e3e44fece219780d Mon Sep 17 00:00:00 2001 From: Markus Volk Date: Wed, 30 Sep 2026 01:04:51 +0200 Subject: [PATCH] bmap-writer: honour ImageSize for the last block Writing an image whose size is not a multiple of the bmap block size failed at its last block with "Image ended before the block map did", because every range was taken to end at (endBlock + 1) * BlockSize. Add a patch that reads ImageSize from the bmap and clamps the ranges to it. Tested by writing a wic image whose size ends 2048 bytes into its last 4 KiB block to an NVMe disk. AI-Generated: Uses Claude Code (Claude Fable 5.1) Signed-off-by: Markus Volk Signed-off-by: Khem Raj --- .../bmap-writer/bmap-writer_1.0.5.bb | 1 + ...-Honour-ImageSize-for-the-last-block.patch | 85 +++++++++++++++++++ 2 files changed, 86 insertions(+) create mode 100644 meta-oe/recipes-support/bmap-writer/files/0001-Honour-ImageSize-for-the-last-block.patch diff --git a/meta-oe/recipes-support/bmap-writer/bmap-writer_1.0.5.bb b/meta-oe/recipes-support/bmap-writer/bmap-writer_1.0.5.bb index 71ea721eed..3aefaa436f 100644 --- a/meta-oe/recipes-support/bmap-writer/bmap-writer_1.0.5.bb +++ b/meta-oe/recipes-support/bmap-writer/bmap-writer_1.0.5.bb @@ -10,6 +10,7 @@ LIC_FILES_CHKSUM = "file://LICENSE;md5=e49f4652534af377a713df3d9dec60cb" SRC_URI = "git://github.com/embetrix/${BPN};branch=master;protocol=https;tag=${PV} \ file://0001-device-Use-the-C-library-s-ioctl-request-type-for-BL.patch \ + file://0001-Honour-ImageSize-for-the-last-block.patch \ " SRCREV = "c7b1bec0f40217d17e315226552e461a4a816abc" diff --git a/meta-oe/recipes-support/bmap-writer/files/0001-Honour-ImageSize-for-the-last-block.patch b/meta-oe/recipes-support/bmap-writer/files/0001-Honour-ImageSize-for-the-last-block.patch new file mode 100644 index 0000000000..1943256d71 --- /dev/null +++ b/meta-oe/recipes-support/bmap-writer/files/0001-Honour-ImageSize-for-the-last-block.patch @@ -0,0 +1,85 @@ +From e63a11dedcdece8b9b285485a86405fd258b37d8 Mon Sep 17 00:00:00 2001 +From: Markus Volk +Date: Tue, 29 Sep 2026 17:29:52 +0200 +Subject: [PATCH] Honour ImageSize for the last block + +bmaptool records the exact image size in ImageSize, and the last block +of an image whose size is not a multiple of BlockSize is only partly +filled. Writing and verifying used (endBlock + 1) * BlockSize as the end +of every range, so the range containing that block asked for more bytes +than the image has and the write failed with "Image ended before the +block map did". Read ImageSize and clamp the end of each range to it. + +AI-Generated: Uses Claude Code (Claude Fable 5.1) +Upstream-Status: Pending +--- + src/bmap.cpp | 5 +++++ + src/bmap.h | 1 + + src/image_writer.cpp | 2 +- + src/main.cpp | 2 +- + 4 files changed, 8 insertions(+), 2 deletions(-) + +diff --git a/src/bmap.cpp b/src/bmap.cpp +index fabf2c2..0162ac0 100644 +--- a/src/bmap.cpp ++++ b/src/bmap.cpp +@@ -135,6 +135,7 @@ int parseBMap(const std::string &filename, bmap_t& bmapData) { + bmapData.bmapVersion = (version != nullptr) ? trimWhitespace(version) : "unknown"; + + // Parse image information ++ bmapData.imageSize = requireChildUnsigned(p_root, "ImageSize"); + bmapData.blocksTotal = requireChildUnsigned(p_root, "BlocksCount"); + bmapData.blocksMapped = requireChildUnsigned(p_root, "MappedBlocksCount"); + bmapData.blockSize = requireChildUnsigned(p_root, "BlockSize"); +@@ -200,6 +201,10 @@ int validateBmap(const bmap_t& bmap, uint64_t deviceSize) { + if (bmap.blocksTotal == 0) { + throw BmapError("BMAP: BlocksCount must not be zero"); + } ++ if (bmap.imageSize > bmap.blocksTotal * bmap.blockSize || ++ bmap.imageSize <= (bmap.blocksTotal - 1) * bmap.blockSize) { ++ throw BmapError("BMAP: ImageSize does not match BlocksCount and BlockSize"); ++ } + if (bmap.blocksMapped > bmap.blocksTotal) { + throw BmapError("BMAP: MappedBlocksCount exceeds BlocksCount"); + } +diff --git a/src/bmap.h b/src/bmap.h +index cf6ff9d..98cb969 100644 +--- a/src/bmap.h ++++ b/src/bmap.h +@@ -38,6 +38,7 @@ struct bmap_t { + std::string checksumType; + size_t blockSize = 0; + size_t blocksTotal = 0; ++ size_t imageSize = 0; + size_t blocksMapped = 0; + std::string bmapVersion; + std::string bmapChecksum; +diff --git a/src/image_writer.cpp b/src/image_writer.cpp +index bb802ea..f864151 100644 +--- a/src/image_writer.cpp ++++ b/src/image_writer.cpp +@@ -177,7 +177,7 @@ int BmapWriteImage(int fd, const bmap_t &bmap, int dev_fd, const std::string &de + for (const auto &range : bmap.ranges) { + // validateBmap() has already proven that none of this can overflow. + const size_t outStart = range.startBlock * bmap.blockSize; +- const size_t outEnd = (range.endBlock + 1) * bmap.blockSize; ++ const size_t outEnd = std::min((range.endBlock + 1) * bmap.blockSize, bmap.imageSize); + const size_t rangeSize = outEnd - outStart; + const off_t writeOffset = static_cast(outStart); + size_t writtenSize = 0; +diff --git a/src/main.cpp b/src/main.cpp +index ca42c12..b8cbbc5 100644 +--- a/src/main.cpp ++++ b/src/main.cpp +@@ -166,7 +166,7 @@ int main(int argc, char *argv[]) { + FdGuard imageGuard(image_fd); + + std::cout << "BMAP format version: " << bmap.bmapVersion << std::endl; +- std::cout << "Image size: " << (bmap.blocksTotal * bmap.blockSize) << " bytes" << std::endl; ++ std::cout << "Image size: " << bmap.imageSize << " bytes" << std::endl; + std::cout << "Block size: " << bmap.blockSize << " bytes" << std::endl; + std::cout << "Mapped blocks: " << bmap.blocksMapped << " out of " << bmap.blocksTotal + << " (" << std::fixed << std::setprecision(1) +-- +2.55.0 +