Reviewed-by: phco...@gmail.com
Le jeu. 29 août 2024, 14:07, Rasmus Villemoes via Grub-devel <
grub-devel@gnu.org> a écrit :
> Unlike files accessed via a normal file system, the file->read_hook is
> not honoured when using blocklist notation.
>
> This means that when trying to use a dedicated, 1KiB, raw partition
> for the environment block and hence does something like
>
> save_env --file=(hd0,gpt9)0+2 X Y Z
>
> this fails with "sparse file not allowed", which is rather unexpected,
> as I've explicitly said exactly which blocks should be used. Adding a
> little debugging reveals that grub_file_size (file) is 1024 as
> expected, but total_length is 0, simply because the callback was never
> invoked, so blocklists is an empty list.
>
> Fix that by honouring the ->read_hook set by the caller, also when a
> "file" is specified with blocklist notation.
>
> Signed-off-by: Rasmus Villemoes <rasmus.villem...@prevas.dk>
> ---
> I've tried to keep the patch at a minimum, but since the
> disk->read_hook needs to be cleared on all return paths, it seemed a
> little easier to drop the 'return -1' and instead set ret and break.
>
> For readability, it seemed best to introduce the disk local variable to
> hold file->device->disk, and then there's no point in not also using
> that in the grub_disk_read() call.
>
> grub-core/kern/fs.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/grub-core/kern/fs.c b/grub-core/kern/fs.c
> index 7ad0aaf4e..79f1a797c 100644
> --- a/grub-core/kern/fs.c
> +++ b/grub-core/kern/fs.c
> @@ -215,12 +215,15 @@ grub_fs_blocklist_read (grub_file_t file, char *buf,
> grub_size_t len)
> grub_disk_addr_t sector;
> grub_off_t offset;
> grub_ssize_t ret = 0;
> + grub_disk_t disk = file->device->disk;
>
> if (len > file->size - file->offset)
> len = file->size - file->offset;
>
> sector = (file->offset >> GRUB_DISK_SECTOR_BITS);
> offset = (file->offset & (GRUB_DISK_SECTOR_SIZE - 1));
> + disk->read_hook = file->read_hook;
> + disk->read_hook_data = file->read_hook_data;
> for (p = file->data; p->length && len > 0; p++)
> {
> if (sector < p->length)
> @@ -232,9 +235,12 @@ grub_fs_blocklist_read (grub_file_t file, char *buf,
> grub_size_t len)
> >> GRUB_DISK_SECTOR_BITS) > p->length - sector)
> size = ((p->length - sector) << GRUB_DISK_SECTOR_BITS) -
> offset;
>
> - if (grub_disk_read (file->device->disk, p->offset + sector,
> offset,
> + if (grub_disk_read (disk, p->offset + sector, offset,
> size, buf) != GRUB_ERR_NONE)
> - return -1;
> + {
> + ret = -1;
> + break;
> + }
>
> ret += size;
> len -= size;
> @@ -244,6 +250,7 @@ grub_fs_blocklist_read (grub_file_t file, char *buf,
> grub_size_t len)
> else
> sector -= p->length;
> }
> + disk->read_hook = 0;
>
> return ret;
> }
> --
> 2.46.0
>
>
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