[PATCH v2 3/4] commit-graph.c: write non-split graphs as read-only
- From
Taylor Blau <me@ttaylorr.com>
- Date
- Apr 27, 2020, 16:28 UTC
- Message-ID
- <86cf29ce9c1e6dc1fc881458c18850c2893b092a.1588004647.git.me@ttaylorr.com>
- In-Reply-To
- <cover.1588004647.git.me@ttaylorr.com>
In the previous commit, Git learned 'hold_lock_file_for_update_mode' to allow the caller to specify the permission bits (prior to further adjustment by the umask and shared repository permissions) used when acquiring a temporary file.
Use this in the commit-graph machinery for writing a non-split graph to acquire an opened temporary file with permissions read-only permissions to match the split behavior. (In the split case, Git uses git_mkstemp_mode' for each of the commit-graph layers with permission bits '0444').
One can notice this discrepancy when moving a non-split graph to be part of a new chain. This causes a commit-graph chain where all layers have read-only permission bits, except for the base layer, which is writable for the current user.
Resolve this discrepancy by using the new 'hold_lock_file_for_update_mode' and passing the desired permission bits.
Doing so causes some test fallout in t5318 and t6600. In t5318, this occurs in tests that corrupt a commit-graph file by writing into it. For these, 'chmod u+w'-ing the file beforehand resolves the issue. The additional spot in 'corrupt_graph_verify' is necessary because of the extra 'git commit-graph write' beforehand (which *does* rewrite the commit-graph file). In t6600, this is caused by copying a read-only commit-graph file into place and then trying to replace it. For these, make these files writable.
Signed-off-by: Taylor Blau <me@ttaylorr.com> --- commit-graph.c | 3 ++- t/t5318-commit-graph.sh | 11 ++++++++++- t/t6600-test-reach.sh | 2 ++ 3 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/commit-graph.c b/commit-graph.c index f013a84e29..5b5047a7dd 100644 --- a/commit-graph.c +++ b/commit-graph.c @@ -1388,7 +1388,8 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx) f = hashfd(fd, ctx->graph_name); } else { - hold_lock_file_for_update(&lk, ctx->graph_name, LOCK_DIE_ON_ERROR); + hold_lock_file_for_update_mode(&lk, ctx->graph_name, + LOCK_DIE_ON_ERROR, 0444); fd = lk.tempfile->fd; f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf); } diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh index 9bf920ae17..fb0aae61c3 100755 --- a/t/t5318-commit-graph.sh +++ b/t/t5318-commit-graph.sh @@ -96,6 +96,13 @@ test_expect_success 'write graph' ' graph_read_expect "3" ' +test_expect_success POSIXPERM 'write graph has correct permissions' ' + test_path_is_file $objdir/info/commit-graph && + echo "-r--r--r--" >expect && + test_modebits $objdir/info/commit-graph >actual && + test_cmp expect actual +' + graph_git_behavior 'graph exists' full commits/3 commits/1 test_expect_success 'Add more commits' ' @@ -421,7 +428,8 @@ GRAPH_BYTE_FOOTER=$(($GRAPH_OCTOPUS_DATA_OFFSET + 4 * $NUM_OCTOPUS_EDGES)) corrupt_graph_setup() { cd "$TRASH_DIRECTORY/full" && test_when_finished mv commit-graph-backup $objdir/info/commit-graph && - cp $objdir/info/commit-graph commit-graph-backup + cp $objdir/info/commit-graph commit-graph-backup && + chmod u+w $objdir/info/commit-graph } corrupt_graph_verify() { @@ -435,6 +443,7 @@ corrupt_graph_verify() { fi && git status --short && GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD=true git commit-graph write && + chmod u+w $objdir/info/commit-graph && git commit-graph verify } diff --git a/t/t6600-test-reach.sh b/t/t6600-test-reach.sh index b24d850036..475564bee7 100755 --- a/t/t6600-test-reach.sh +++ b/t/t6600-test-reach.sh @@ -51,8 +51,10 @@ test_expect_success 'setup' ' done && git commit-graph write --reachable && mv .git/objects/info/commit-graph commit-graph-full && + chmod u+w commit-graph-full && git show-ref -s commit-5-5 | git commit-graph write --stdin-commits && mv .git/objects/info/commit-graph commit-graph-half && + chmod u+w commit-graph-half && git config core.commitGraph true '
-- 2.26.0.113.ge9739cdccc