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authorDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2019-10-07 11:20:55 +0200
committerDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2019-10-07 12:22:05 +0200
commita68eb730558fb90bc8d9524564d8f9e58f3ccac1 (patch)
treede7a678b28786ec2e47e4956d8cdb0f4466f3d5c /lib/sqfs/data_writer
parentc7fdb2b305ed8b4deb67bfc6ef3257e7e6773397 (diff)
Improve ABI backward & forward compatibillity
- Padd the compressor config union - 128 bytes aught to be enough for everyone, i.e. future compressors. - Insist that the padding space is initialized to 0. If a field gets added to an existing compressor, it can test for 0 as a sentinel value. - Add a size field to the hook structure, aka "the Microsoft way". - The explanation is in the comment. - Don't make the Microsoft mistake of checking for >=, insist on *exact* size match. Future users will need a fallback if their hooks are rejected. But at least they will be rejected instead of silently not being used. - Add an unsupported flag check to the dir tree reader. - Add a basic abi unit test that, for now, checks the size of the compressor config struct fields. Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Diffstat (limited to 'lib/sqfs/data_writer')
-rw-r--r--lib/sqfs/data_writer/common.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/lib/sqfs/data_writer/common.c b/lib/sqfs/data_writer/common.c
index 059ef41..a19eb6d 100644
--- a/lib/sqfs/data_writer/common.c
+++ b/lib/sqfs/data_writer/common.c
@@ -157,9 +157,13 @@ int sqfs_data_writer_write_fragment_table(sqfs_data_writer_t *proc,
return 0;
}
-void sqfs_data_writer_set_hooks(sqfs_data_writer_t *proc, void *user_ptr,
- const sqfs_block_hooks_t *hooks)
+int sqfs_data_writer_set_hooks(sqfs_data_writer_t *proc, void *user_ptr,
+ const sqfs_block_hooks_t *hooks)
{
+ if (hooks->size != sizeof(*hooks))
+ return SQFS_ERROR_UNSUPPORTED;
+
proc->hooks = hooks;
proc->user_ptr = user_ptr;
+ return 0;
}