Teach the listener thread to shutdown the daemon if the spelling of the
worktree root directory changes.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Force shutdown fsmonitor daemon if the worktree root directory
is moved, renamed, or deleted.
Use Windows low-level GetFileInformationByHandle() to get and
compare the Windows system unique ID for the directory with a
cached version when we started up. This lets us detect the
case where someone renames the directory that we are watching
and then creates a new directory with the original pathname.
This is important because we are listening to a named pipe for
requests and they are stored in the Named Pipe File System (NPFS)
which a kernel-resident pseudo filesystem not associated with
the actual NTFS directory.
For example, if the daemon was watching "~/foo/", it would have
a directory-watch handle on that directory and a named-pipe
handle for "//./pipe/...foo". Moving the directory to "~/bar/"
does not invalidate the directory handle. (So the daemon would
actually be watching "~/bar" but listening on "//./pipe/...foo".
If the user then does "git init ~/foo" and causes another daemon
to start, the first daemon will still have ownership of the pipe
and the second daemon instance will fail to start. "git status"
clients in "~/foo" will ask "//./pipe/...foo" about changes and
the first daemon instance will tell them about "~/bar".
This commit causes the first daemon to shutdown if the system unique
ID for "~/foo" changes (changes from what it was when the daemon
started). Shutdown occurs after a periodic poll. After the
first daemon exits and releases the lock on the named pipe,
subsequent Git commands may cause another daemon to be started
on "~/foo". Similarly, a subsequent Git command may cause another
daemon to be started on "~/bar".
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Extend the Windows version of the "health" thread to periodically
inspect the system and shutdown if warranted.
This commit updates the thread's wait loop to use a timeout and
defines a (currently empty) table of functions to poll the system.
A later commit will add functions to the table to actually
inspect the system.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Create another thread to watch over the daemon process and
automatically shut it down if necessary.
This commit creates the basic framework for a "health" thread
to monitor the daemon and/or the file system. Later commits
will add platform-specific code to do the actual work.
The "health" thread is intended to monitor conditions that
would be difficult to track inside the IPC thread pool and/or
the file system listener threads. For example, when there are
file system events outside of the watched worktree root or if
we want to have an idle-timeout auto-shutdown feature.
This commit creates the health thread itself, defines the thread-proc
and sets up the thread's event loop. It integrates this new thread
into the existing IPC and Listener thread models.
This commit defines the API to the platform-specific code where all of
the monitoring will actually happen.
The platform-specific code for MacOS is just stubs. Meaning that the
health thread will immediately exit on MacOS, but that is OK and
expected. Future work can define MacOS-specific monitoring.
The platform-specific code for Windows sets up enough of the
WaitForMultipleObjects() machinery to watch for system and/or custom
events. Currently, the set of wait handles only includes our custom
shutdown event (sent from our other theads). Later commits in this
series will extend the set of wait handles to monitor other
conditions.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Rename platform-specific listener thread related variables
and data types as we prepare to add another backend thread
type.
[] `struct fsmonitor_daemon_backend_data` becomes `struct fsm_listen_data`
[] `state->backend_data` becomes `state->listen_data`
[] `state->error_code` becomes `state->listen_error_code`
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Teach the fsmonitor--daemon to CD outside of the worktree
before starting up.
The common Git startup mechanism causes the CWD of the daemon process
to be in the root of the worktree. On Windows, this causes the daemon
process to hold a locked handle on the CWD and prevents other
processes from moving or deleting the worktree while the daemon is
running.
CD to HOME before entering main event loops.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Ignore FSEvents resulting from `xattr` changes. Git does not care about
xattr's or changes to xattr's, so don't waste time collecting these
events in the daemon nor transmitting them to clients.
Various security tools add xattrs to files and/or directories, such as
to mark them as having been downloaded. We should ignore these events
since it doesn't affect the content of the file/directory or the normal
meta-data that Git cares about.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
On MacOS mark repos on NTFS or FAT32 volumes as incompatible.
The builtin FSMonitor used Unix domain sockets on MacOS for IPC
with clients. These sockets are kept in the .git directory.
Unix sockets are not supported by NTFS and FAT32, so the daemon
cannot start up.
Test for this during our compatibility checking so that client
commands do not keep trying to start the daemon.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Teach Git to detect remote working directories on Windows and mark them as
incompatible with FSMonitor.
With this `git fsmonitor--daemon run` will error out with a message like it
does for bare repos.
Client commands, such as `git status`, will not attempt to start the daemon.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Teach Git to detect remote working directories on macOS and mark them as
incompatible with FSMonitor.
With this, `git fsmonitor--daemon run` will error out with a message
like it does for bare repos.
Client commands, like `git status`, will not attempt to start the daemon.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
VFS for Git virtual repositories are incompatible with FSMonitor.
VFS for Git is a downstream fork of Git. It contains its own custom
file system watcher that is aware of the virtualization. If a working
directory is being managed by VFS for Git, we should not try to watch
it because we may get incomplete results.
We do not know anything about how VFS for Git works, but we do
know that VFS for Git working directories contain a well-defined
config setting. If it is set, mark the working directory as
incompatible.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Extend generic incompatibility checkout with platform-specific
mechanism. Stub in Win32 version.
In the existing fsmonitor-settings code we have a way to mark
types of repos as incompatible with fsmonitor (whether via the
hook and IPC APIs). For example, we do this for bare repos,
since there are no files to watch.
Extend this exclusion mechanism for platform-specific reasons.
This commit just creates the framework and adds a stub for Win32.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Teach FSMonitor daemon on Windows to recognize shortname paths as
aliases of normal longname paths. FSMonitor clients, such as `git
status`, should receive the longname spelling of changed files (when
possible).
Sometimes we receive FS events using the shortname, such as when a CMD
shell runs "RENAME GIT~1 FOO" or "RMDIR GIT~1". The FS notification
arrives using whatever combination of long and shortnames were used by
the other process. (Shortnames do seem to be case normalized,
however.)
Use Windows GetLongPathNameW() to try to map the pathname spelling in
the notification event into the normalized longname spelling. (This
can fail if the file/directory is deleted, moved, or renamed, because
we are asking the FS for the mapping in response to the event and
after it has already happened, but we try.)
Special case the shortname spelling of ".git" to avoid under-reporting
these events.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Built-in fsmonitor (part 2).
* jh/builtin-fsmonitor-part2: (30 commits)
t7527: test status with untracked-cache and fsmonitor--daemon
fsmonitor: force update index after large responses
fsmonitor--daemon: use a cookie file to sync with file system
fsmonitor--daemon: periodically truncate list of modified files
t/perf/p7519: add fsmonitor--daemon test cases
t/perf/p7519: speed up test on Windows
t/perf/p7519: fix coding style
t/helper/test-chmtime: skip directories on Windows
t/perf: avoid copying builtin fsmonitor files into test repo
t7527: create test for fsmonitor--daemon
t/helper/fsmonitor-client: create IPC client to talk to FSMonitor Daemon
help: include fsmonitor--daemon feature flag in version info
fsmonitor--daemon: implement handle_client callback
compat/fsmonitor/fsm-listen-darwin: implement FSEvent listener on MacOS
compat/fsmonitor/fsm-listen-darwin: add MacOS header files for FSEvent
compat/fsmonitor/fsm-listen-win32: implement FSMonitor backend on Windows
fsmonitor--daemon: create token-based changed path cache
fsmonitor--daemon: define token-ids
fsmonitor--daemon: add pathname classification
fsmonitor--daemon: implement 'start' command
...
Finishing touches to C rewrite of "git add -i" in single-key
interactive mode.
* pw/add-p-single-key:
terminal: restore settings on SIGTSTP
terminal: work around macos poll() bug
terminal: don't assume stdin is /dev/tty
terminal: use flags for save_term()
Replace core.fsyncObjectFiles with two new configuration variables,
core.fsync and core.fsyncMethod.
* ns/core-fsyncmethod:
core.fsync: documentation and user-friendly aggregate options
core.fsync: new option to harden the index
core.fsync: add configuration parsing
core.fsync: introduce granular fsync control infrastructure
core.fsyncmethod: add writeout-only mode
wrapper: make inclusion of Windows csprng header tightly scoped
Include MacOS system declarations to allow us to use FSEvent and
CoreFoundation APIs. We need different versions of the declarations
for GCC vs. clang because of compiler and header file conflicts.
While it is quite possible to #include Apple's CoreServices.h when
compiling C source code with clang, trying to build it with GCC
currently fails with this error:
In file included
from /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/System/...
...Library/Frameworks/Security.framework/Headers/AuthSession.h:32,
from /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/System/...
...Library/Frameworks/Security.framework/Headers/Security.h:42,
from /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/System/...
...Library/Frameworks/CoreServices.framework/Frameworks/...
...OSServices.framework/Headers/CSIdentity.h:43,
from /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/System/...
...Library/Frameworks/CoreServices.framework/Frameworks/...
...OSServices.framework/Headers/OSServices.h:29,
from /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/System/...
...Library/Frameworks/CoreServices.framework/Frameworks/...
...LaunchServices.framework/Headers/IconsCore.h:23,
from /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/System/...
...Library/Frameworks/CoreServices.framework/Frameworks/...
...LaunchServices.framework/Headers/LaunchServices.h:23,
from /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/System/...
...Library/Frameworks/CoreServices.framework/Headers/CoreServices.h:45,
/Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/System/...
...Library/Frameworks/Security.framework/Headers/Authorization.h:193:7:
error: variably modified 'bytes' at file scope
193 | char bytes[kAuthorizationExternalFormLength];
| ^~~~~
The underlying reason is that GCC (rightfully) objects that an `enum`
value such as `kAuthorizationExternalFormLength` is not a constant
(because it is not, the preprocessor has no knowledge of it, only the
actual C compiler does) and can therefore not be used to define the size
of a C array.
This is a known problem and tracked in GCC's bug tracker:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93082
In the meantime, let's not block things and go the slightly ugly route
of declaring/defining the FSEvents constants, data structures and
functions that we need, so that we can avoid above-mentioned issue.
Let's do this _only_ for GCC, though, so that the CI/PR builds (which
build both with clang and with GCC) can guarantee that we _are_ using
the correct data types.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach the win32 backend to register a watch on the working tree
root directory (recursively). Also watch the <gitdir> if it is
not inside the working tree. And to collect path change notifications
into batches and publish.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Stub in empty implementation of fsmonitor--daemon
backend for Darwin (aka MacOS).
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Stub in empty filesystem listener backend for fsmonitor--daemon on Windows.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* maint-2.34:
Git 2.34.2
Git 2.33.2
Git 2.32.1
Git 2.31.2
GIT-VERSION-GEN: bump to v2.33.1
Git 2.30.3
setup_git_directory(): add an owner check for the top-level directory
Add a function to determine whether a path is owned by the current user
* maint-2.33:
Git 2.33.2
Git 2.32.1
Git 2.31.2
GIT-VERSION-GEN: bump to v2.33.1
Git 2.30.3
setup_git_directory(): add an owner check for the top-level directory
Add a function to determine whether a path is owned by the current user
* maint-2.32:
Git 2.32.1
Git 2.31.2
Git 2.30.3
setup_git_directory(): add an owner check for the top-level directory
Add a function to determine whether a path is owned by the current user
* maint-2.31:
Git 2.31.2
Git 2.30.3
setup_git_directory(): add an owner check for the top-level directory
Add a function to determine whether a path is owned by the current user
* maint-2.30:
Git 2.30.3
setup_git_directory(): add an owner check for the top-level directory
Add a function to determine whether a path is owned by the current user
The single-key interactive operation used by "git add -p" has been
made more robust.
* pw/single-key-interactive:
add -p: disable stdin buffering when interactive.singlekey is set
terminal: set VMIN and VTIME in non-canonical mode
terminal: pop signal handler when terminal is restored
terminal: always reset terminal when reading without echo
This function will be used in the next commit to prevent
`setup_git_directory()` from discovering a repository in a directory
that is owned by someone other than the current user.
Note: We cannot simply use `st.st_uid` on Windows just like we do on
Linux and other Unix-like platforms: according to
https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/stat-functions
this field is always zero on Windows (because Windows' idea of a user ID
does not fit into a single numerical value). Therefore, we have to do
something a little involved to replicate the same functionality there.
Also note: On Windows, a user's home directory is not actually owned by
said user, but by the administrator. For all practical purposes, it is
under the user's control, though, therefore we pretend that it is owned
by the user.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
mingw-w64's pthread_unistd.h had a bug that mistakenly (because there is
no support for the *lockfile() functions required[1]) defined
_POSIX_THREAD_SAFE_FUNCTIONS and that was being worked around since
3ecd153a3b (compat/mingw: support MSys2-based MinGW build, 2016-01-14).
The bug was fixed in winphtreads, but as a side effect, leaves the
reentrant functions from time.h no longer visible and therefore breaks
the build.
Since the intention all along was to avoid using the fallback functions,
formalize the use of POSIX by setting the corresponding feature flag and
compile out the implementation for the fallback functions.
[1] https://unix.org/whitepapers/reentrant.html
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Acked-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If the user suspends git while it is waiting for a keypress reset the
terminal before stopping and restore the settings when git resumes. If
the user tries to resume in the background print an error
message (taking care to use async safe functions) before stopping
again. Ideally we would reprint the prompt for the user when git
resumes but this patch just restarts the read().
The signal handler is established with sigaction() rather than using
sigchain_push() as this allows us to control the signal mask when the
handler is invoked and ensure SA_RESTART is used to restart the
read() when resuming.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
On macos the builtin "add -p" does not handle keys that generate
escape sequences because poll() does not work with terminals
there. Switch to using select() on non-windows platforms to work
around this.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
read_key_without_echo() reads from stdin but uses /dev/tty when it
disables echo. This is unfortunate as there no guarantee that stdin is
the same device as /dev/tty. The perl version of "add -p" uses stdin
when it sets the terminal mode, this commit does the same for the
builtin version. There is still a difference between the perl and
builtin versions though - the perl version will ignore any errors when
setting the terminal mode[1] and will still read single bytes when
stdin is not a terminal. The builtin version displays a warning if
setting the terminal mode fails and switches to reading a line at a
time.
[1] b061c913bb/ReadKey.xs (L1090)
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The next commit will add another flag in addition to the existing
full_duplex so change the function signature to take a flags
argument. Also alter the functions that call save_term() so that they
can pass flags down to it.
The choice to use an enum for tho bitwise flags is because gdb will
display the symbolic names of all the flags that are set rather than
the integer value.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit introduces the `core.fsyncMethod` configuration
knob, which can currently be set to `fsync` or `writeout-only`.
The new writeout-only mode attempts to tell the operating system to
flush its in-memory page cache to the storage hardware without issuing a
CACHE_FLUSH command to the storage controller.
Writeout-only fsync is significantly faster than a vanilla fsync on
common hardware, since data is written to a disk-side cache rather than
all the way to a durable medium. Later changes in this patch series will
take advantage of this primitive to implement batching of hardware
flushes.
When git_fsync is called with FSYNC_WRITEOUT_ONLY, it may fail and the
caller is expected to do an ordinary fsync as needed.
On Apple platforms, the fsync system call does not issue a CACHE_FLUSH
directive to the storage controller. This change updates fsync to do
fcntl(F_FULLFSYNC) to make fsync actually durable. We maintain parity
with existing behavior on Apple platforms by setting the default value
of the new core.fsyncMethod option.
Signed-off-by: Neeraj Singh <neerajsi@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Including NTSecAPI.h in git-compat-util.h causes build errors in any
other file that includes winternl.h. NTSecAPI.h was included in order to
get access to the RtlGenRandom cryptographically secure PRNG. This
change scopes the inclusion of ntsecapi.h to wrapper.c, which is the only
place that it's actually needed.
The build breakage is due to the definition of UNICODE_STRING in
NtSecApi.h:
#ifndef _NTDEF_
typedef LSA_UNICODE_STRING UNICODE_STRING, *PUNICODE_STRING;
typedef LSA_STRING STRING, *PSTRING ;
#endif
LsaLookup.h:
typedef struct _LSA_UNICODE_STRING {
USHORT Length;
USHORT MaximumLength;
#ifdef MIDL_PASS
[size_is(MaximumLength/2), length_is(Length/2)]
#endif // MIDL_PASS
PWSTR Buffer;
} LSA_UNICODE_STRING, *PLSA_UNICODE_STRING;
winternl.h also defines UNICODE_STRING:
typedef struct _UNICODE_STRING {
USHORT Length;
USHORT MaximumLength;
PWSTR Buffer;
} UNICODE_STRING;
typedef UNICODE_STRING *PUNICODE_STRING;
Both definitions have equivalent layouts. Apparently these internal
Windows headers aren't designed to be included together. This is
an oversight in the headers and does not represent an incompatibility
between the APIs.
Signed-off-by: Neeraj Singh <neerajsi@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* pw/single-key-interactive:
add -p: disable stdin buffering when interactive.singlekey is set
terminal: set VMIN and VTIME in non-canonical mode
terminal: pop signal handler when terminal is restored
terminal: always reset terminal when reading without echo
The mingw_utime implementation in mingw.c does not support
directories. This means that "test-tool chmtime" fails on Windows when
targeting directories. This has previously been noted and sidestepped
temporarily by Jeff Hostetler, in "t/helper/test-chmtime: skip
directories on Windows" in the "Builtin FSMonitor Part 2" work, but
not yet fixed.
It would make sense to backdate file and folder changes in untracked
cache tests, to avoid needing to insert explicit delays/pauses in the
tests.
Add support for directory date manipulation in mingw_utime by
replacing the file-oriented _wopen() call with the
directory-supporting CreateFileW() windows API explicitly.
Signed-off-by: Tao Klerks <tao@klerks.biz>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If VMIN and VTIME are both set to zero then the terminal performs
non-blocking reads which means that read_key_without_echo() returns
EOF if there is no key press pending. This results in the user being
unable to select anything when running "git add -p". Fix this by
explicitly setting VMIN and VTIME when enabling non-canonical mode.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When disable_bits() changes the terminal attributes it uses
sigchain_push_common() to restore the terminal if a signal is received
before restore_term() is called. However there is no corresponding
call to sigchain_pop_common() when the settings are restored so the
signal handler is left on the sigchain stack. This leaves the stack
unbalanced so code such as
sigchain_push_common(my_handler);
...
read_key_without_echo(...);
...
sigchain_pop_common();
pops the handler pushed by disable_bits() rather than the one it
intended to. Additionally "git add -p" changes the terminal settings
every time it reads a key press so the stack can grow significantly.
In order to fix this save_term() now sets up the signal handler so
restore_term() can unconditionally call sigchain_pop_common(). There
are no callers of save_term() outside of terminal.c as the only
external caller was removed by e3f7e01b50 ("Revert "editor: save and
reset terminal after calling EDITOR"", 2021-11-22). Any future callers
of save_term() should benefit from having the signal handler set up
for them.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Break out of the loop to ensure restore_term() is called before
returning.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The build procedure has been taught to notice older version of zlib
and enable our replacement uncompress2() automatically.
* ab/auto-detect-zlib-compress2:
compat: auto-detect if zlib has uncompress2()
Pick a better random number generator and use it when we prepare
temporary filenames.
* bc/csprng-mktemps:
wrapper: use a CSPRNG to generate random file names
wrapper: add a helper to generate numbers from a CSPRNG
Fix a hand-rolled alloca() imitation that may have violated
alignment requirement of data being sorted in compatibility
implementation of qsort_s() and stable qsort().
* jc/qsort-s-alignment-fix:
stable-qsort: avoid using potentially unaligned access
compat/qsort_s.c: avoid using potentially unaligned access
We have a copy of uncompress2() implementation in compat/ so that we
can build with an older version of zlib that lack the function, and
the build procedure selects if it is used via the NO_UNCOMPRESS2
$(MAKE) variable. This is yet another "annoying" knob the porters
need to tweak on platforms that are not common enough to have the
default set in the config.mak.uname file.
Attempt to instead ask the system header <zlib.h> to decide if we
need the compatibility implementation. This is a deviation from the
way we have been handling the "compatiblity" features so far, and if
it can be done cleanly enough, it could work as a model for features
that need compatibility definition we discover in the future. With
that goal in mind, avoid expedient but ugly hacks, like shoving the
code that is conditionally compiled into an unrelated .c file, which
may not work in future cases---instead, take an approach that uses a
file that is independently compiled and stands on its own.
Compile and link compat/zlib-uncompress2.c file unconditionally, but
conditionally hide the implementation behind #if/#endif when zlib
version is 1.2.9 or newer, and unconditionally archive the resulting
object file in the libgit.a to be picked up by the linker.
There are a few things to note in the shape of the code base after
this change:
- We no longer use NO_UNCOMPRESS2 knob; if the system header
<zlib.h> claims a version that is more cent than the library
actually is, this would break, but it is easy to add it back when
we find such a system.
- The object file compat/zlib-uncompress2.o is always compiled and
archived in libgit.a, just like a few other compat/ object files
already are.
- The inclusion of <zlib.h> is done in <git-compat-util.h>; we used
to do so from <cache.h> which includes <git-compat-util.h> as the
first thing it does, so from the *.c codes, there is no practical
change.
- Until objects in libgit.a that is already used gains a reference
to the function, the reftable code will be the only one that
wants it, so libgit.a on the linker command line needs to appear
once more at the end to satisify the mutual dependency.
- Beat found a trick used by OpenSSL to avoid making the
conditionally-compiled object truly empty (apparently because
they had to deal with compilers that do not want to see an
effectively empty input file). Our compat/zlib-uncompress2.c
file borrows the same trick for portabilty.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Helped-by: Beat Bolli <dev+git@drbeat.li>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A recent upstream topic introduced checks for certain Git commands that
prevent them from deleting the current working directory, introducing
also a regression test that ensures that commands such as `git version`
_can_ run without a current working directory.
While technically not possible on Windows via the regular Win32 API, we
do run the regression tests in an MSYS2 Bash which uses a POSIX
emulation layer (the MSYS2/Cygwin runtime) where a really evil hack
_does_ allow to delete a directory even if it is the current working
directory.
Therefore, Git needs to be prepared for a missing working directory,
even on Windows.
This issue was not noticed in upstream Git because there was no caller
that tried to discover a Git directory with a deleted current working
directory in the test suite. But in the microsoft/git fork, we do want
to run `pre-command`/`post-command` hooks for every command, even for
`git version`, which means that we make precisely such a call. The bug
is not in that `pre-command`/`post-command` feature, though, but in
`mingw_getcwd()` and needs to be addressed there.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are many situations in which having access to a cryptographically
secure pseudorandom number generator (CSPRNG) is helpful. In the
future, we'll encounter one of these when dealing with temporary files.
To make this possible, let's add a function which reads from a system
CSPRNG and returns some bytes.
We know that all systems will have such an interface. A CSPRNG is
required for a secure TLS or SSH implementation and a Git implementation
which provided neither would be of little practical use. In addition,
POSIX is set to standardize getentropy(2) in the next version, so in the
(potentially distant) future we can rely on that.
For systems which lack one of the other interfaces, we provide the
ability to use OpenSSL's CSPRNG. OpenSSL is highly portable and
functions on practically every known OS, and we know it will have access
to some source of cryptographically secure randomness. We also provide
support for the arc4random in libbsd for folks who would prefer to use
that.
Because this is a security sensitive interface, we take some
precautions. We either succeed by filling the buffer completely as we
requested, or we fail. We don't return partial data because the caller
will almost never find that to be a useful behavior.
Specify a makefile knob which users can use to specify one or more
suitable CSPRNGs, and turn the multiple string options into a set of
defines, since we cannot match on strings in the preprocessor. We allow
multiple options to make the job of handling this in autoconf easier.
The order of options is important here. On systems with arc4random,
which is most of the BSDs, we use that, since, except on MirBSD and
macOS, it uses ChaCha20, which is extremely fast, and sits entirely in
userspace, avoiding a system call. We then prefer getrandom over
getentropy, because the former has been available longer on Linux, and
then OpenSSL. Finally, if none of those are available, we use
/dev/urandom, because most Unix-like operating systems provide that API.
We prefer options that don't involve device files when possible because
those work in some restricted environments where device files may not be
available.
Set the configuration variables appropriately for Linux and the BSDs,
including macOS, as well as Windows and NonStop. We specifically only
consider versions which receive publicly available security support
here. For the same reason, we don't specify getrandom(2) on Linux,
because CentOS 7 doesn't support it in glibc (although its kernel does)
and we don't want to resort to making syscalls.
Finally, add a test helper to allow this to be tested by hand and in
tests. We don't add any tests, since invoking the CSPRNG is not likely
to produce interesting, reproducible results.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Christoph Reiter reported on the Git for Windows issue tracker[1], that
mingw_strftime() imports strftime() from ucrtbase.dll with the wrong
calling convention. It should be __cdecl instead of WINAPI, which we
always use in DECLARE_PROC_ADDR().
The MSYS2 project encountered cmake sefaults on x86 Windows caused by
the same issue in the cmake source. [2] There are no known git crashes
that where caused by this, yet, but we should try to prevent them.
We import two other non-WINAPI functions via DECLARE_PROC_ADDR(), too.
* NtSetSystemInformation() (NTAPI)
* GetUserNameExW() (SEC_ENTRY)
NTAPI, SEC_ENTRY and WINAPI are all ususally defined as __stdcall,
but there are circumstances where they're defined differently.
Teach DECLARE_PROC_ADDR() about calling conventions and be explicit
about when we want to use which calling convention.
Import winnt.h for the definition of NTAPI and sspi.h for SEC_ENTRY
near their respective only users.
[1] https://github.com/git-for-windows/git/issues/3560
[2] https://github.com/msys2/MINGW-packages/issues/10152
Reported-By: Christoph Reiter <reiter.christoph@gmail.com>
Signed-off-by: Matthias Aßhauer <mha1993@live.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
