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slirp: check for ioctlsocket error and 0-length udp payload.

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Sometimes sorecvfrom() is called from slirp.c because revents == G_IO_IN,
but there is 0 bytes available and recvfrom could be blocking indefinitely.
This is likely due to 0-length udp payload. This also adds an error
checking for ioctlsocket.

Signed-off-by: Vic Lee <llyzs.vic@gmail.com>
Message-Id: <20190301064809.3074-1-llyzs.vic@gmail.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
This commit is contained in:
Vic Lee 2019-03-01 14:48:09 +08:00 committed by Samuel Thibault
parent 8cabd8778c
commit 6c419a1e06
1 changed files with 9 additions and 1 deletions
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10
slirp/socket.c
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@ -529,6 +529,15 @@ sorecvfrom(struct socket *so)
int n; int n;
#endif #endif
if (ioctlsocket(so->s, FIONREAD, &n) != 0) {
DEBUG_MISC(" ioctlsocket errno = %d-%s\n",
errno,strerror(errno));
return;
}
if (n == 0) {
return;
}
m = m_get(so->slirp); m = m_get(so->slirp);
if (!m) { if (!m) {
return; return;
@ -552,7 +561,6 @@ sorecvfrom(struct socket *so)
*/ */
len = M_FREEROOM(m); len = M_FREEROOM(m);
/* if (so->so_fport != htons(53)) { */ /* if (so->so_fport != htons(53)) { */
ioctlsocket(so->s, FIONREAD, &n);
if (n > len) { if (n > len) {
n = (m->m_data - m->m_dat) + m->m_len + n + 1; n = (m->m_data - m->m_dat) + m->m_len + n + 1;