From: Johannes Schindelin <johannes.schindelin@xxxxxx>
Cygwin emulates Unix sockets by writing files with custom contents and
then marking them as system files.
The tricky problem is that while the file is written and its `system`
bit is set, it is still identified as a file. This caused test failures
when Git is too fast looking for the Unix sockets and then complains
that there is a plain file in the way.
Let's work around this by adding a delayed retry loop, specifically for
Cygwin.
Signed-off-by: Johannes Schindelin <johannes.schindelin@xxxxxx>
---
simple-ipc: work around issues with Cygwin's Unix socket emulation
Adam Dinwoodie reported problems running the simple-ipc tests on Cygwin
[https://lore.kernel.org/git/20211104194619.GA12886@xxxxxxxxxxxxx]. This
patch works around the underlying problem, which is rooted in Cygwin's
implementation details.
With this patch, I could not reproduce the problem, even with sh
t0052-simple-ipc.sh --stress-limit=30.
As per Junio's encouragement
[https://lore.kernel.org/git/xmqqee7ozyx4.fsf@gitster.g], I am
submitting this still in the -rc phase, hoping that it will make it into
v2.34.0 final.
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1074%2Fdscho%2Fcygwin-vs-simple-ipc-workaround-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1074/dscho/cygwin-vs-simple-ipc-workaround-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/1074
compat/simple-ipc/ipc-unix-socket.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/compat/simple-ipc/ipc-unix-socket.c b/compat/simple-ipc/ipc-unix-socket.c
index 4e28857a0a1..28a79289d4f 100644
--- a/compat/simple-ipc/ipc-unix-socket.c
+++ b/compat/simple-ipc/ipc-unix-socket.c
@@ -35,6 +35,28 @@ enum ipc_active_state ipc_get_active_state(const char *path)
}
}
+#ifdef __CYGWIN__
+ /*
+ * Cygwin emulates Unix sockets by writing special-crafted files whose
+ * `system` bit is set.
+ *
+ * If we are too fast, Cygwin might still be in the process of marking
+ * the underlying file as a system file. Until then, we will not see a
+ * Unix socket here, but a plain file instead. Just in case that this
+ * is happening, wait a little and try again.
+ */
+ {
+ static const int delay[] = { 1, 10, 20, 40, -1 };
+ int i;
+
+ for (i = 0; S_ISREG(st.st_mode) && delay[i] > 0; i++) {
+ sleep_millisec(delay[i]);
+ if (lstat(path, &st) == -1)
+ return IPC_STATE__INVALID_PATH;
+ }
+ }
+#endif
+
/* also complain if a plain file is in the way */
if ((st.st_mode & S_IFMT) != S_IFSOCK)
return IPC_STATE__INVALID_PATH;
base-commit: 6c220937e2b26d85920bf2d38ff2464a0d57fd6b
--
gitgitgadget
