diff mbox series

[v4,04/11] osdep: implement qemu_socketpair() for win32

Message ID 20230306122751.2355515-5-marcandre.lureau@redhat.com
State New
Headers show
Series QMP command to import win32 sockets | expand

Commit Message

Marc-André Lureau March 6, 2023, 12:27 p.m. UTC 
From: Marc-André Lureau <marcandre.lureau@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.lureau@redhat.com>
---
 include/qemu/sockets.h |   2 -
 util/oslib-win32.c     | 110 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 110 insertions(+), 2 deletions(-)

Comments

Daniel P. Berrangé March 7, 2023, 2:50 p.m. UTC | #1 
On Mon, Mar 06, 2023 at 04:27:44PM +0400, marcandre.lureau@redhat.com wrote:
> From: Marc-André Lureau <marcandre.lureau@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.lureau@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
Marc-André Lureau March 8, 2023, 6:53 a.m. UTC | #2 
Hi

On Tue, Mar 7, 2023 at 6:50 PM Daniel P. Berrangé <berrange@redhat.com> wrote:
>
> On Mon, Mar 06, 2023 at 04:27:44PM +0400, marcandre.lureau@redhat.com wrote:
> > From: Marc-André Lureau <marcandre.lureau@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.lureau@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 ?

yeah, I guess switching back to sync and getting the peer pid,

I assume the unix socket pair to be ready at this 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)
>

That's hopefully not necessary.

thanks

>
>
> > +
> > +    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 :|
>
>
Daniel P. Berrangé March 8, 2023, 9:27 a.m. UTC | #3 
On Wed, Mar 08, 2023 at 10:53:13AM +0400, Marc-André Lureau wrote:
> Hi
> 
> On Tue, Mar 7, 2023 at 6:50 PM Daniel P. Berrangé <berrange@redhat.com> wrote:
> >
> > On Mon, Mar 06, 2023 at 04:27:44PM +0400, marcandre.lureau@redhat.com wrote:
> > > From: Marc-André Lureau <marcandre.lureau@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.lureau@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 ?
> 
> yeah, I guess switching back to sync and getting the peer pid,
> 
> I assume the unix socket pair to be ready at this point.

Ok, lets hope its ok, but remember this if we see any non-deterministic
failures 

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>



With regards,
Daniel
diff mbox series

Patch

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;
+    }
+
+    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;
+    }
+
+    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)