Commit fdb990bd authored by Rémi Denis-Courmont's avatar Rémi Denis-Courmont

Remove potential deadlocks in waitpipe with net_*

parent d9b51113
......@@ -555,26 +555,26 @@ int __vlc_object_waitpipe( vlc_object_t *obj )
vlc_spin_lock (&internals->spin);
signaled = internals->b_signaled;
if ((!signaled) && (internals->pipes[0] == -1))
if (internals->pipes[0] == -1)
{
internals->pipes[0] = pfd[0];
internals->pipes[1] = pfd[1];
}
else
race = VLC_TRUE;
}
vlc_spin_unlock (&internals->spin);
if (race || signaled)
{
if (race)
{ /* Race condition: two threads call pipe() - unlikely */
close (pfd[0]);
close (pfd[1]);
if (signaled)
{ /* vlc_object_signal() was already invoked! */
errno = EINTR;
return -1;
}
}
if (signaled)
/* Race condition: lc_object_signal() already invoked! */
while (write (internals->pipes[1], &(char){ 0 }, 1) < 0);
return internals->pipes[0];
}
......
......@@ -258,7 +258,8 @@ int *net_Listen (vlc_object_t *p_this, const char *psz_host,
*****************************************************************************
* Reads from a network socket.
* If waitall is true, then we repeat until we have read the right amount of
* data; in that case, a short count means EOF has been reached.
* data; in that case, a short count means EOF has been reached or the VLC
* object has been signaled.
*****************************************************************************/
ssize_t
__net_Read (vlc_object_t *restrict p_this, int fd, const v_socket_t *vs,
......@@ -270,27 +271,17 @@ __net_Read (vlc_object_t *restrict p_this, int fd, const v_socket_t *vs,
{ .fd = -1, .events = POLLIN },
};
vlc_object_lock (p_this);
ufd[1].fd = vlc_object_waitpipe (p_this);
while (i_buflen > 0)
{
int val;
if (!vlc_object_alive (p_this))
ufd[1].fd = vlc_object_waitpipe (p_this);
if (ufd[1].fd == -1)
{
#if defined(WIN32) || defined(UNDER_CE)
WSASetLastError (WSAEINTR);
#else
errno = EINTR;
#endif
goto error;
}
ufd[0].revents = ufd[1].revents = 0;
vlc_object_unlock (p_this);
val = poll (ufd, sizeof (ufd) / sizeof (ufd[0]), -1);
vlc_object_lock (p_this);
if (val < 0)
goto error;
......@@ -298,9 +289,16 @@ __net_Read (vlc_object_t *restrict p_this, int fd, const v_socket_t *vs,
if (ufd[1].revents)
{
msg_Dbg (p_this, "socket %d polling interrupted", fd);
vlc_object_wait (p_this);
msg_Dbg (p_this, "socket %d polling restarting", fd);
continue;
if (i_total == 0)
{
#if defined(WIN32) || defined(UNDER_CE)
WSASetLastError (WSAEINTR);
#else
errno = EINTR;
#endif
goto error;
}
break;
}
assert (ufd[0].revents);
......@@ -378,13 +376,10 @@ __net_Read (vlc_object_t *restrict p_this, int fd, const v_socket_t *vs,
break;
}
vlc_object_unlock (p_this);
return i_total;
error:
msg_Err (p_this, "Read error: %m");
vlc_object_unlock (p_this);
return -1;
}
......
......@@ -286,10 +286,9 @@ int __net_Accept( vlc_object_t *p_this, int *pi_fd, mtime_t i_wait )
assert( pi_fd != NULL );
vlc_object_lock (p_this);
evfd = vlc_object_waitpipe (p_this);
while (vlc_object_alive (p_this))
for (;;)
{
unsigned n = 0;
while (pi_fd[n] != -1)
......@@ -303,8 +302,9 @@ int __net_Accept( vlc_object_t *p_this, int *pi_fd, mtime_t i_wait )
ufd[i].events = POLLIN;
ufd[i].revents = 0;
}
if (evfd == -1)
n--; /* avoid EBADF */
vlc_object_unlock (p_this);
switch (poll (ufd, n, timeout))
{
case -1:
......@@ -313,11 +313,9 @@ int __net_Accept( vlc_object_t *p_this, int *pi_fd, mtime_t i_wait )
case 0:
return -1; /* NOTE: p_this already unlocked */
}
vlc_object_lock (p_this);
if (ufd[n].revents)
{
vlc_object_wait (p_this);
errno = EINTR;
break;
}
......@@ -338,11 +336,9 @@ int __net_Accept( vlc_object_t *p_this, int *pi_fd, mtime_t i_wait )
*/
memmove (pi_fd + i, pi_fd + i + 1, n - (i + 1));
pi_fd[n - 1] = sfd;
vlc_object_unlock (p_this);
return fd;
}
}
vlc_object_unlock (p_this);
return -1;
}
......
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