On Mon, Mar 06, 2023 at 04:27:44PM +0400, marcandre.lur...@redhat.com wrote: > From: Marc-André Lureau <marcandre.lur...@redhat.com> > > Manually implement a socketpair() function, using UNIX sockets and > simple peer credential checking. > > QEMU doesn't make much use of socketpair, beside vhost-user which is not > available for win32 at this point. However, I intend to use it for > writing some new portable tests. > > Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com> > --- > include/qemu/sockets.h | 2 - > util/oslib-win32.c | 110 +++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 110 insertions(+), 2 deletions(-) > > diff --git a/include/qemu/sockets.h b/include/qemu/sockets.h > index 2b0698a7c9..d935fd80da 100644 > --- a/include/qemu/sockets.h > +++ b/include/qemu/sockets.h > @@ -15,7 +15,6 @@ int inet_aton(const char *cp, struct in_addr *ia); > bool fd_is_socket(int fd); > int qemu_socket(int domain, int type, int protocol); > > -#ifndef WIN32 > /** > * qemu_socketpair: > * @domain: specifies a communication domain, such as PF_UNIX > @@ -30,7 +29,6 @@ int qemu_socket(int domain, int type, int protocol); > * Return 0 on success. > */ > int qemu_socketpair(int domain, int type, int protocol, int sv[2]); > -#endif > > int qemu_accept(int s, struct sockaddr *addr, socklen_t *addrlen); > /* > diff --git a/util/oslib-win32.c b/util/oslib-win32.c > index 29a667ae3d..16f8a67f7e 100644 > --- a/util/oslib-win32.c > +++ b/util/oslib-win32.c > @@ -310,6 +310,116 @@ bool qemu_socket_unselect(int sockfd, Error **errp) > return qemu_socket_select(sockfd, NULL, 0, errp); > } > > +int qemu_socketpair(int domain, int type, int protocol, int sv[2]) > +{ > + struct sockaddr_un addr = { > + 0, > + }; > + socklen_t socklen; > + int listener = -1; > + int client = -1; > + int server = -1; > + g_autofree char *path = NULL; > + int tmpfd; > + u_long arg; > + int ret = -1; > + > + g_return_val_if_fail(sv != NULL, -1); > + > + addr.sun_family = AF_UNIX; > + socklen = sizeof(addr); > + > + tmpfd = g_file_open_tmp(NULL, &path, NULL); > + if (tmpfd == -1 || !path) { > + errno = EACCES; > + goto out; > + } > + > + close(tmpfd); > + > + if (strlen(path) >= sizeof(addr.sun_path)) { > + errno = EINVAL; > + goto out; > + } > + > + strncpy(addr.sun_path, path, sizeof(addr.sun_path) - 1); > + > + listener = socket(domain, type, protocol); > + if (listener == -1) { > + goto out; > + } > + > + if (DeleteFile(path) == 0 && GetLastError() != ERROR_FILE_NOT_FOUND) { > + errno = EACCES; > + goto out; > + } > + g_clear_pointer(&path, g_free); > + > + if (bind(listener, (struct sockaddr *)&addr, socklen) == -1) { > + goto out; > + } > + > + if (listen(listener, 1) == -1) { > + goto out; > + } > + > + client = socket(domain, type, protocol); > + if (client == -1) { > + goto out; > + } > + > + arg = 1; > + if (ioctlsocket(client, FIONBIO, &arg) != NO_ERROR) { > + goto out; > + } > + > + if (connect(client, (struct sockaddr *)&addr, socklen) == -1 && > + WSAGetLastError() != WSAEWOULDBLOCK) { > + goto out; > + } > + > + server = accept(listener, NULL, NULL); > + if (server == -1) { > + goto out; > + }
In theory at this point 'client' if connect() returned WSAEWOULDBLOCK, then at this point it should be fully connected. I wonder if that is actually guaranteed though, or should we do something to validate there's no race condition ? > + > + arg = 0; > + if (ioctlsocket(client, FIONBIO, &arg) != NO_ERROR) { > + goto out; > + } > + > + arg = 0; > + if (ioctlsocket(client, SIO_AF_UNIX_GETPEERPID, &arg) != NO_ERROR) { > + goto out; > + } Maybe this will force a synchronization point ? Alteratively select() + getsockopt(SO_ERROR) is what we used to do to check for connect() completion (logic removed now but can be seen in b2587932582333197c88bf663785b19f441989d7) > + > + if (arg != GetCurrentProcessId()) { > + errno = EPERM; > + goto out; > + } > + > + sv[0] = server; > + server = -1; > + sv[1] = client; > + client = -1; > + ret = 0; > + > +out: > + if (listener != -1) { > + close(listener); > + } > + if (client != -1) { > + close(client); > + } > + if (server != -1) { > + close(server); > + } > + if (path) { > + DeleteFile(path); > + } > + return ret; > +} > + > #undef connect > int qemu_connect_wrap(int sockfd, const struct sockaddr *addr, > socklen_t addrlen) > -- > 2.39.2 > With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|