procyberian/emacs
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Fix hang when deleting a pipe process

Browse source 
* src/w32.h (FILE_DONT_CLOSE): New flag.
* src/w32.c (sys_close): Don't close descriptors used to read from
the pipe process.  Leave the FILE_DONT_CLOSE flag set in the
descriptor's info.
(register_aux_fd): Set the FILE_DONT_CLOSE flag in the
descriptor's info.
* src/w32proc.c (reader_thread): When exiting normally, close the
file descriptor used to read from a pipe process.  (Bug#52414)
This commit is contained in:
Eli Zaretskii 2021-12-11 20:15:53 +02:00
parent 8c50016b10
commit a81669c69f
3 changed files with 39 additions and 11 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

28
src/w32.c
View file

@ -8548,7 +8548,7 @@ fcntl (int s, int cmd, int options)
int
sys_close (int fd)
{
int rc;
int rc = -1;
if (fd < 0)
{
@ -8603,14 +8603,31 @@ sys_close (int fd)
}
}
if (fd >= 0 && fd < MAXDESC)
fd_info[fd].flags = 0;
/* Note that sockets do not need special treatment here (at least on
NT and Windows 95 using the standard tcp/ip stacks) - it appears that
closesocket is equivalent to CloseHandle, which is to be expected
because socket handles are fully fledged kernel handles. */
rc = _close (fd);
if (fd < MAXDESC)
{
if ((fd_info[fd].flags & FILE_DONT_CLOSE) == 0)
{
fd_info[fd].flags = 0;
rc = _close (fd);
}
else
{
/* We don't close here descriptors open by pipe processes
for reading from the pipe, because the reader thread
might be stuck in _sys_read_ahead, and then we will hang
here. If the reader thread exits normally, it will close
the descriptor; otherwise we will leave a zombie thread
hanging around. */
rc = 0;
/* Leave the flag set for the reader thread to close the
descriptor. */
fd_info[fd].flags = FILE_DONT_CLOSE;
}
}
return rc;
}
@ -10898,6 +10915,7 @@ register_aux_fd (int infd)
}
fd_info[ infd ].cp = cp;
fd_info[ infd ].hnd = (HANDLE) _get_osfhandle (infd);
fd_info[ infd ].flags |= FILE_DONT_CLOSE;
}
#ifdef HAVE_GNUTLS

1
src/w32.h
View file

@ -135,6 +135,7 @@ extern filedesc fd_info [ MAXDESC ];
#define FILE_SOCKET 0x0200
#define FILE_NDELAY 0x0400
#define FILE_SERIAL 0x0800
#define FILE_DONT_CLOSE 0x1000
extern child_process * new_child (void);
extern void delete_child (child_process *cp);

21
src/w32proc.c
View file

@ -1206,6 +1206,7 @@ static DWORD WINAPI
reader_thread (void *arg)
{
child_process *cp;
int fd;
/* Our identity */
cp = (child_process *)arg;
@ -1220,12 +1221,13 @@ reader_thread (void *arg)
{
int rc;
if (cp->fd >= 0 && (fd_info[cp->fd].flags & FILE_CONNECT) != 0)
rc = _sys_wait_connect (cp->fd);
else if (cp->fd >= 0 && (fd_info[cp->fd].flags & FILE_LISTEN) != 0)
rc = _sys_wait_accept (cp->fd);
fd = cp->fd;
if (fd >= 0 && (fd_info[fd].flags & FILE_CONNECT) != 0)
rc = _sys_wait_connect (fd);
else if (fd >= 0 && (fd_info[fd].flags & FILE_LISTEN) != 0)
rc = _sys_wait_accept (fd);
else
rc = _sys_read_ahead (cp->fd);
rc = _sys_read_ahead (fd);
/* Don't bother waiting for the event if we already have been
told to exit by delete_child. */
@ -1238,7 +1240,7 @@ reader_thread (void *arg)
{
DebPrint (("reader_thread.SetEvent(0x%x) failed with %lu for fd %ld (PID %d)\n",
(DWORD_PTR)cp->char_avail, GetLastError (),
cp->fd, cp->pid));
fd, cp->pid));
return 1;
}
@ -1266,6 +1268,13 @@ reader_thread (void *arg)
if (cp->status == STATUS_READ_ERROR)
break;
}
/* If this thread was reading from a pipe process, close the
descriptor used for reading, as sys_close doesn't in that case. */
if (fd_info[fd].flags == FILE_DONT_CLOSE)
{
fd_info[fd].flags = 0;
_close (fd);
}
return 0;
}