commit 2b02ed351e68831d6bd5bc93f18d563679084a51
from: Stefan Sperling <stsp@stsp.name>
via: Thomas Adam <thomas@xteddy.org>
date: Tue Jul 22 08:17:38 2025 UTC

reset file position when reusing per-repository temporary files

When reusing a temporary file, do not forget to reset its file position
to zero. Otherwise, opening multiple raw objects in a row can fail during
delta application with an unexpected file size reported by stat(2).

Problem reported by Aaron Lin

Problem reproduced and fix verified with a repository provided by Aaron.
I have unsuccessfully tried to write a regression test for this.

ok op@

commit - 04b841e4697edff06c9f91aacea329b970b76f59
commit + 2b02ed351e68831d6bd5bc93f18d563679084a51
blob - 25d0ffb75d7e8448d934b6c293c32e6502583ca6
blob + 287ba8003842bf4e78f4beda762dda10d88e453b
--- lib/repository.c
+++ lib/repository.c
@@ -395,6 +395,8 @@ got_repo_temp_fds_get(int *fd, int *idx, struct got_re
 		if (repo->tempfiles[i] != -1) {
 			if (ftruncate(repo->tempfiles[i], 0L) == -1)
 				return got_error_from_errno("ftruncate");
+			if (lseek(repo->tempfiles[i], 0L, SEEK_SET) == -1)
+				return got_error_from_errno("lseek");
 			*fd = repo->tempfiles[i];
 			*idx = i;
 			repo->tempfile_use_mask |= (1 << i);