gio: add G_CREDENTIALS_TYPE_WIN32_PID

Credentials are often used to check peer processes details.

With AF_UNIX sockets on Windows, SIO_AF_UNIX_GETPEERPID can
be used to retrive the peer PID.

We will probably introduce more advanced mechanisms later on, though,
but I am not a Windows API expert.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

gio/gcredentials.c

@@ -72,6 +72,9 @@
  * On Solaris (including OpenSolaris and its derivatives), the native
  * credential type is a `ucred_t`. This corresponds to
  * %G_CREDENTIALS_TYPE_SOLARIS_UCRED.
+ *
+ * Since GLib 2.72, on Windows, the native credentials may contain the PID of a
+ * process. This corresponds to %G_CREDENTIALS_TYPE_WIN32_PID.
  */
 
 /**
@@ -100,6 +103,8 @@ struct _GCredentials
   struct sockpeercred native;
 #elif G_CREDENTIALS_USE_SOLARIS_UCRED
   ucred_t *native;
+#elif G_CREDENTIALS_USE_WIN32_PID
+  DWORD native;
 #else
   #ifdef __GNUC__
   #pragma GCC diagnostic push
@@ -188,6 +193,8 @@ g_credentials_init (GCredentials *credentials)
   credentials->native.gid = getegid ();
 #elif G_CREDENTIALS_USE_SOLARIS_UCRED
   credentials->native = ucred_get (P_MYID);
+#elif G_CREDENTIALS_USE_WIN32_PID
+  credentials->native = GetCurrentProcessId ();
 #endif
 }
 
@@ -293,6 +300,8 @@ g_credentials_to_string (GCredentials *credentials)
     if (ret->str[ret->len - 1] == ',')
       ret->str[ret->len - 1] = '\0';
   }
+#elif G_CREDENTIALS_USE_WIN32_PID
+  g_string_append_printf (ret, "win32-pid:pid=%lu", credentials->native);
 #else
   g_string_append (ret, "unknown");
 #endif
@@ -600,6 +609,8 @@ g_credentials_get_unix_pid (GCredentials    *credentials,
   ret = credentials->native.pid;
 #elif G_CREDENTIALS_USE_SOLARIS_UCRED
   ret = ucred_getpid (credentials->native);
+#elif G_CREDENTIALS_USE_WIN32_PID
+  ret = credentials->native;
 #else
 
 #if G_CREDENTIALS_USE_APPLE_XUCRED

gio/gcredentialsprivate.h

@@ -40,6 +40,7 @@
 #undef G_CREDENTIALS_USE_OPENBSD_SOCKPEERCRED
 #undef G_CREDENTIALS_USE_SOLARIS_UCRED
 #undef G_CREDENTIALS_USE_APPLE_XUCRED
+#undef G_CREDENTIALS_USE_WIN32_PID
 
 /*
  * G_CREDENTIALS_NATIVE_TYPE:
@@ -171,6 +172,14 @@
 void _g_credentials_set_local_peerid (GCredentials *credentials,
                                       pid_t         pid);
 
+#elif defined(_WIN32)
+#define G_CREDENTIALS_SUPPORTED 1
+#define G_CREDENTIALS_USE_WIN32_PID 1
+#define G_CREDENTIALS_NATIVE_TYPE G_CREDENTIALS_TYPE_WIN32_PID
+#define G_CREDENTIALS_NATIVE_SIZE (sizeof (DWORD))
+#define G_CREDENTIALS_SOCKET_GET_CREDENTIALS_SUPPORTED 1
+#define G_CREDENTIALS_HAS_PID 1
+
 #endif
 
 #endif /* __G_CREDENTIALS_PRIVATE_H__ */

gio/gioenums.h

@@ -1441,6 +1441,7 @@ typedef enum
  * @G_CREDENTIALS_TYPE_SOLARIS_UCRED: The native credentials type is a `ucred_t`. Added in 2.40.
  * @G_CREDENTIALS_TYPE_NETBSD_UNPCBID: The native credentials type is a `struct unpcbid`. Added in 2.42.
  * @G_CREDENTIALS_TYPE_APPLE_XUCRED: The native credentials type is a `struct xucred`. Added in 2.66.
+ * @G_CREDENTIALS_TYPE_WIN32_PID: The native credentials type is a PID `DWORD`. Added in 2.72.
  *
  * Enumeration describing different kinds of native credential types.
  *
@@ -1455,6 +1456,7 @@ typedef enum
   G_CREDENTIALS_TYPE_SOLARIS_UCRED,
   G_CREDENTIALS_TYPE_NETBSD_UNPCBID,
   G_CREDENTIALS_TYPE_APPLE_XUCRED,
+  G_CREDENTIALS_TYPE_WIN32_PID,
 } GCredentialsType;
 
 /**

gio/gsocket.c

@@ -76,6 +76,10 @@
 #include "glibintl.h"
 #include "gioprivate.h"
 
+#ifdef G_OS_WIN32
+#include "giowin32-afunix.h"
+#endif
+
 /**
  * SECTION:gsocket
  * @short_description: Low-level socket object
@@ -6129,6 +6133,23 @@ g_socket_get_credentials (GSocket   *socket,
         ucred_free (ucred);
       }
   }
+#elif G_CREDENTIALS_USE_WIN32_PID
+  {
+    DWORD peerid, drc;
+
+    if (WSAIoctl (socket->priv->fd, SIO_AF_UNIX_GETPEERPID,
+                  NULL, 0U,
+                  &peerid, sizeof(peerid),
+                  /* Windows bug: always 0 https://github.com/microsoft/WSL/issues/4676 */
+                  &drc,
+                  NULL, NULL) == 0)
+      {
+        ret = g_credentials_new ();
+        g_credentials_set_native (ret,
+                                  G_CREDENTIALS_TYPE_WIN32_PID,
+                                  &peerid);
+      }
+  }
 #else
   #error "G_CREDENTIALS_SOCKET_GET_CREDENTIALS_SUPPORTED is set but this is no code for this platform"
 #endif

gio/tests/credentials.c

@@ -25,6 +25,28 @@
 #include <gio/gio.h>
 #include <gio/gcredentialsprivate.h>
 
+#ifdef G_OS_WIN32
+
+static void
+test_basic (void)
+{
+  GCredentials *creds = g_credentials_new ();
+  gchar *stringified;
+  DWORD *pid;
+
+  stringified = g_credentials_to_string (creds);
+  g_test_message ("%s", stringified);
+  g_free (stringified);
+
+  pid = g_credentials_get_native (creds,
+                                  G_CREDENTIALS_TYPE_WIN32_PID);
+  g_assert_cmpuint (*pid, ==, GetCurrentProcessId ());
+
+  g_object_unref (creds);
+}
+
+#else
+
 static void
 test_basic (void)
 {
@@ -177,6 +199,8 @@ test_basic (void)
   g_object_unref (other);
 }
 
+#endif /* !G_OS_WIN32 */
+
 int
 main (int   argc,
       char *argv[])