From: Daan De Meyer Date: Sun, 5 Apr 2026 08:17:59 +0000 (+0000) Subject: boot: generalize CDROM terminology to El Torito X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c82cf5662e25591ca50831b8b386fa2da94dd3c1;p=thirdparty%2Fsystemd.git boot: generalize CDROM terminology to El Torito Per UEFI specification §13.3.2, El Torito partition discovery applies to any block device, not just optical media. Rename disk_get_part_uuid_cdrom() to disk_get_part_uuid_eltorito() and update all log messages and comments to say "El Torito" instead of "CDROM" to reflect this. --- diff --git a/src/boot/part-discovery.c b/src/boot/part-discovery.c index 9249dc24a18..8f5fefad47c 100644 --- a/src/boot/part-discovery.c +++ b/src/boot/part-discovery.c @@ -320,21 +320,23 @@ EFI_STATUS partition_open(const EFI_GUID *type, EFI_HANDLE *device, EFI_HANDLE * return EFI_SUCCESS; } -static char16_t* disk_get_part_uuid_cdrom(const EFI_DEVICE_PATH *dp) { +static char16_t* disk_get_part_uuid_eltorito(const EFI_DEVICE_PATH *dp) { EFI_STATUS err; assert(dp); - /* When booting from a CD-ROM via El Torito, the device path contains a CDROM node instead of - * a HARDDRIVE node. The CDROM node doesn't carry a partition UUID, so we need to read the GPT - * from the underlying disk to find it. */ + /* When booting via El Torito, the device path contains a CDROM node instead of a HARDDRIVE + * node (UEFI specification §10.3.5.2). The CDROM node doesn't carry a partition UUID, so we + * need to read the GPT from the underlying disk to find it. Per §13.3.2, El Torito partition + * discovery applies to any block device, not just optical media (e.g. an ISO image dd'd to a + * USB stick). */ const CDROM_DEVICE_PATH *cdrom = NULL; for (const EFI_DEVICE_PATH *node = dp; !device_path_is_end(node); node = device_path_next_node(node)) if (node->Type == MEDIA_DEVICE_PATH && node->SubType == MEDIA_CDROM_DP) cdrom = (const CDROM_DEVICE_PATH *) node; if (!cdrom) { - log_debug("No CDROM device path node found."); + log_debug("No El Torito device path node found."); return NULL; } @@ -345,7 +347,7 @@ static char16_t* disk_get_part_uuid_cdrom(const EFI_DEVICE_PATH *dp) { EFI_HANDLE disk_handle; err = BS->LocateDevicePath(MAKE_GUID_PTR(EFI_BLOCK_IO_PROTOCOL), &remaining, &disk_handle); if (err != EFI_SUCCESS) { - log_debug_status(err, "Failed to locate disk device for CDROM: %m"); + log_debug_status(err, "Failed to locate disk device for El Torito boot: %m"); return NULL; } @@ -354,13 +356,13 @@ static char16_t* disk_get_part_uuid_cdrom(const EFI_DEVICE_PATH *dp) { EFI_BLOCK_IO_PROTOCOL *block_io; err = BS->HandleProtocol(disk_handle, MAKE_GUID_PTR(EFI_BLOCK_IO_PROTOCOL), (void **) &block_io); if (err != EFI_SUCCESS) { - log_debug_status(err, "Failed to get block I/O protocol for CDROM disk: %m"); + log_debug_status(err, "Failed to get block I/O protocol for El Torito disk: %m"); return NULL; } if (block_io->Media->LogicalPartition || !block_io->Media->MediaPresent || block_io->Media->LastBlock <= 1) { - log_debug("CDROM disk has unsuitable media (partition=%ls, present=%ls, lastblock=%" PRIu64 ").", + log_debug("El Torito disk has unsuitable media (partition=%ls, present=%ls, lastblock=%" PRIu64 ").", yes_no(block_io->Media->LogicalPartition), yes_no(block_io->Media->MediaPresent), (uint64_t) block_io->Media->LastBlock); @@ -369,24 +371,24 @@ static char16_t* disk_get_part_uuid_cdrom(const EFI_DEVICE_PATH *dp) { uint32_t iso9660_block_size = block_io->Media->BlockSize; if (iso9660_block_size < 512 || iso9660_block_size > 4096 || !ISPOWEROF2(iso9660_block_size)) { - log_debug("Unexpected CDROM block size %" PRIu32 ", skipping.", iso9660_block_size); + log_debug("Unexpected El Torito block size %" PRIu32 ", skipping.", iso9660_block_size); return NULL; } EFI_DISK_IO_PROTOCOL *disk_io; err = BS->HandleProtocol(disk_handle, MAKE_GUID_PTR(EFI_DISK_IO_PROTOCOL), (void **) &disk_io); if (err != EFI_SUCCESS) { - log_debug_status(err, "Failed to get disk I/O protocol for CDROM disk: %m"); + log_debug_status(err, "Failed to get disk I/O protocol for El Torito disk: %m"); return NULL; } uint32_t media_id = block_io->Media->MediaId; /* Probe for the GPT header at multiple possible sector sizes (512, 1024, 2048, 4096). - * The GPT header is at LBA 1, i.e. byte offset == sector_size. On CD-ROMs, the GPT + * The GPT header is at LBA 1, i.e. byte offset == sector_size. On El Torito media, the GPT * may use a different sector size than the media's block size (e.g. 512-byte GPT sectors - * on 2048-byte CD-ROM blocks), so we try all possibilities. If the primary GPT header is - * corrupt but contains a valid backup LBA, fall back to the backup header. */ + * on 2048-byte blocks), so we try all possibilities. If the primary GPT header is corrupt + * but contains a valid backup LBA, fall back to the backup header. */ uint32_t gpt_sector_size = 0; GptHeader gpt; _cleanup_free_ void *entries = NULL; @@ -413,18 +415,18 @@ static char16_t* disk_get_part_uuid_cdrom(const EFI_DEVICE_PATH *dp) { } if (gpt_sector_size == 0) { - log_debug("No valid GPT found on CDROM at any sector size."); + log_debug("No valid GPT found on El Torito disk at any sector size."); return NULL; } - log_debug("Found GPT on CDROM with sector size %" PRIu32 ", %" PRIu32 " partition entries.", + log_debug("Found GPT on El Torito disk with sector size %" PRIu32 ", %" PRIu32 " partition entries.", gpt_sector_size, gpt.NumberOfPartitionEntries); - /* Find the partition whose byte offset matches the CDROM's PartitionStart. - * CDROM PartitionStart is in media iso9660_block_size units, GPT StartingLBA is in gpt_sector_size units. */ + /* Find the partition whose byte offset matches the El Torito PartitionStart. + * El Torito PartitionStart is in media iso9660_block_size units, GPT StartingLBA is in gpt_sector_size units. */ uint64_t cdrom_start; if (!MUL_SAFE(&cdrom_start, cdrom->PartitionStart, iso9660_block_size)) { - log_debug("CDROM start offset overflow."); + log_debug("El Torito start offset overflow."); return NULL; } @@ -441,7 +443,7 @@ static char16_t* disk_get_part_uuid_cdrom(const EFI_DEVICE_PATH *dp) { return xasprintf(GUID_FORMAT_STR, GUID_FORMAT_VAL(entry->UniquePartitionGUID)); } - log_debug("No ESP partition matches CDROM start offset %" PRIu64 " (block size %" PRIu32 ").", + log_debug("No ESP partition matches El Torito start offset %" PRIu64 " (block size %" PRIu32 ").", cdrom->PartitionStart, iso9660_block_size); return NULL; } @@ -470,6 +472,6 @@ char16_t *disk_get_part_uuid(EFI_HANDLE *handle) { return xasprintf(GUID_FORMAT_STR, GUID_FORMAT_VAL(hd->SignatureGuid)); } - /* No GPT partition node found — try CDROM device path as fallback */ - return disk_get_part_uuid_cdrom(dp); + /* No GPT partition node found — try El Torito device path as fallback */ + return disk_get_part_uuid_eltorito(dp); } diff --git a/src/udev/udev-builtin-blkid.c b/src/udev/udev-builtin-blkid.c index 49bb0fbff37..edadb71c7ab 100644 --- a/src/udev/udev-builtin-blkid.c +++ b/src/udev/udev-builtin-blkid.c @@ -426,12 +426,12 @@ static int probe_gpt_boot_disk_needs_loop(UdevEvent *event, int fd) { sd_device *dev = ASSERT_PTR(ASSERT_PTR(event)->dev); int r; - /* Probe the GPT sector size. For CD-ROMs booted via El Torito, the GPT may use a different - * sector size than the device (e.g. 512-byte GPT on a 2048-byte CD-ROM). If there's a mismatch, - * check if this is the boot disk by comparing GPT partition UUIDs with the ESP/XBOOTLDR UUID - * exported by the boot loader. If it matches, set a property so that udev rules can set up a - * loop device with the correct sector size — the kernel can't parse the partition table itself - * in this case. + /* Probe the GPT sector size. For devices booted via El Torito, the GPT may use a different + * sector size than the device (e.g. a 512-byte GPT on a device with 2048-byte blocks). If + * there's a mismatch, check if this is the boot disk by comparing GPT partition UUIDs with the + * ESP/XBOOTLDR UUID exported by the boot loader. If it matches, set a property so that udev + * rules can set up a loop device with the correct sector size — the kernel can't parse the + * partition table itself in this case. * * Even if the sector sizes match, if the device does not support partition scanning (e.g. some * CD-ROM drives), the kernel still can't parse the partition table. In that case, if the disk