It does not help us to check whether the file exists before trying to
unlink it since it might be gone by the time unlink is called.
Instead try to remove it and handle the resulting error if it did not
exist.
Checking the size before we open the file descriptor can lead to the
file being replaced from under us when renames aren't quite atomic, so
we can end up reading too little of the file, leading to us thinking the
file is corrupted.
There might be a few threads or processes working with references
concurrently, so fortify the code to ignore errors which come from
concurrent access which do not stop us from continuing the work.
This includes ignoring an unlinking error. Either someone else removed
it or we leave the file around. In the former case the job is done, and
in the latter case, the ref is still in a valid state.
We need to save the errno, lest we clobber it in the giterr_set()
call. Also add code for reporting that a path component is missing,
which is a distinct failure mode.
In order not to undo concurrent modifications to references, we must
make sure that we only delete a loose reference if it still has the same
value as when we packed it.
This means we need to lock it and then compare the value with the one we
put in the packed file.
We say it's going to work if you use a different repository in each
thread. Let's do precisely that in our code instead of hoping re-using
the refdb is going to work.
This test does fail currently, surfacing existing bugs.
When trying to find a discovery, we walk up the directory
structure checking if there is a ".git" file or directory and, if
so, check its validity. But in the case that we've got a ".git"
file, we do not want to unconditionally assume that the file is
in fact a ".git" file and treat it as such, as we would error out
if it is not.
Fix the issue by only treating a file as a gitlink file if it
ends with "/.git". This allows users of the function to discover
a repository by handing in any path contained inside of a git
repository.
The existing code would set a namespace of "" (empty string) with
GIT_NAMESPACE unset. In a repository where refs/heads/namespaces/
exists, that can produce incorrect results. Detect that case and avoid
setting the namespace at all.
Since that makes the last assignment to error conditional, and the
previous assignment can potentially get GIT_ENOTFOUND, set error to 0
explicitly to prevent the call from incorrectly failing with
GIT_ENOTFOUND.
We're recently trying to upgrade to the current master of libgit2
in Cargo but we're unfortunately hitting a segfault in one of our
tests. This particular test is just a small smoke test that https
works (e.g. it's configured in libgit2). It attempts to clone
from a URL which simply immediately drops connections after
they're accepted (e.g. terminate abnormally). We expect to see a
standard error from libgit2 but unfortunately we're seeing a
segfault.
This segfault is happening inside of the `wait_for` function of
`curl_stream.c` at the line `FD_SET(fd, &errfd)` because `fd` is
-1. This ends up doing an out-of-bounds array access that faults
the program. I tracked back to where this -1 came from to the
line here (returned by `CURLINFO_LASTSOCKET`) and added a check
to return an error.
The code correctly detects that forced creation of a branch on a
nonbare repo should not be able to overwrite a branch which is
the HEAD reference. But there's no reason to prevent this on
a bare repo, and in fact, git allows this. I.e.,
git branch -f master new_sha
works on a bare repo with HEAD set to master. This change fixes
that problem, and updates tests so that, for this case, both the
bare and nonbare cases are checked for correct behavior.
We need to include the initialisation and construction functions in all
backend, so we include this header when building against SecureTransport
and WinHTTP as well.
In `pack_entry_find_offset`, we try to find the offset of a
certain object in the pack file. To do so, we first assert if the
packfile has already been opened and open it if not. Opening the
packfile is guarded with a mutex, so concurrent access to this is
in fact safe.
What is not thread-safe though is our calculation of offsets
inside the packfile. Assume two threads calling
`pack_entry_find_offset` at the same time. We first calculate the
offset and index location and only then determine if the pack has
already been opened. If so, we re-calculate the offset and index
address.
Now the case for two threads: thread 1 first calculates the
addresses and is subsequently suspended. The second thread will
now call `pack_index_open` and initialize the pack file,
calculating its addresses correctly. When the first thread is
resumed now, he'll see that the pack file has already been
initialized and will happily proceed with the addresses it has
already calculated before the check. As the pack file was not
initialized before, these addresses are bogus.
Fix the issue by only calculating the addresses after having
checked if the pack file is open.
When trying to receive packets from the remote, we loop until
either an error distinct to `GIT_EBUFS` occurs or until we
successfully parsed the packet. This does not honor the case
where we are looping over an already closed socket which has no
more data, leaving us in an infinite loop if we got a bogus
packet size or if the remote hang up.
Fix the issue by returning `GIT_EEOF` when we cannot read data
from the socket anymore.
When reading a server's reference announcements via the smart
protocol, we expect the server to send multiple flushes before
the protocol is finished. If we fail to receive new data from the
socket, we will only return an end of stream error if we have not
seen any flush yet.
This logic is flawed in that we may run into an infinite loop
when receiving a server's reference announcement with a bogus
flush packet. E.g. assume the last flushing package is changed to
not be '0000' but instead any other value. In this case, we will
still await one more flush package and ignore the fact that we
are not receiving any data from the socket, causing an infinite
loop.
Fix the issue by always returning `GIT_EEOF` if the socket
indicates an end of stream.
Exercise the logic surrounding deinitialization of the libgit2
library as well as repeated concurrent de- and reinitialization.
This tries to catch races and makes sure that it is possible to
reinitialize libgit2 multiple times.
After deinitializing libgit2, we have to make sure to setup
options required for testing. Currently, this only includes
setting up the configuration search path again. Before, this has
been set up once in `tests/main.c`.
When threading is not enabled for libgit2, we keep global state
in a simple static variable. When libgit2 is shut down, we clean
up the global state by freeing the global state's dynamically
allocated memory. When libgit2 is built with threading, we
additionally free the thread-local storage and thus completely
remove the global state. In a non-threaded build, though, we
simply leave the global state as-is, which may result in an error
upon reinitializing libgit2.
Fix the issue by zeroing out the variable on a shutdown, thus
returning it to its initial state.
