From: Edward Thomson <ethomson@xxxxxxxxxxxxx>
Ensure that when passing a pipe, the gnulib poll replacement will not
return 0 before the timeout has passed.
Not obeying the timeout (and merely returning 0) causes pathological
behavior when preparing a packfile for a repository and taking a
long time to do so. If poll were to return 0 immediately, this would
cause keep-alives to get sent as quickly as possible until the packfile
was created. Such deviance from the standard would cause megabytes (or
more) of keep-alive packets to be sent.
GetTickCount is used as it is efficient, stable and monotonically
increasing. (Neither GetSystemTime nor QueryPerformanceCounter have
all three of these properties.)
Signed-off-by: Edward Thomson <ethomson@xxxxxxxxxxxxx>
Signed-off-by: Johannes Schindelin <johannes.schindelin@xxxxxx>
---
compat/poll/poll.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/compat/poll/poll.c b/compat/poll/poll.c
index a9b41d8..db4e03e 100644
--- a/compat/poll/poll.c
+++ b/compat/poll/poll.c
@@ -446,7 +446,7 @@ poll (struct pollfd *pfd, nfds_t nfd, int timeout)
static HANDLE hEvent;
WSANETWORKEVENTS ev;
HANDLE h, handle_array[FD_SETSIZE + 2];
- DWORD ret, wait_timeout, nhandles;
+ DWORD ret, wait_timeout, nhandles, start = 0, elapsed, orig_timeout = 0;
fd_set rfds, wfds, xfds;
BOOL poll_again;
MSG msg;
@@ -459,6 +459,12 @@ poll (struct pollfd *pfd, nfds_t nfd, int timeout)
return -1;
}
+ if (timeout != INFTIM)
+ {
+ orig_timeout = timeout;
+ start = GetTickCount();
+ }
+
if (!hEvent)
hEvent = CreateEvent (NULL, FALSE, FALSE, NULL);
@@ -603,7 +609,13 @@ poll (struct pollfd *pfd, nfds_t nfd, int timeout)
rc++;
}
- if (!rc && timeout == INFTIM)
+ if (!rc && orig_timeout && timeout != INFTIM)
+ {
+ elapsed = GetTickCount() - start;
+ timeout = elapsed >= orig_timeout ? 0 : orig_timeout - elapsed;
+ }
+
+ if (!rc && timeout)
{
SleepEx (1, TRUE);
goto restart;
--
https://github.com/git/git/pull/176
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