Improve error reporting as part of solving bug #13546 on MS-Windows.

 src/w32.c (sys_socket, sys_bind, sys_connect, sys_gethostname)
 (sys_gethostbyname, sys_getservbyname, sys_getpeername)
 (sys_shutdown, sys_setsockopt, sys_listen, sys_getsockname)
 (sys_accept, sys_recvfrom, sys_sendto, fcntl): In case of failure,
 make sure errno is set to an appropriate value.  (Bug#13546)
 (socket_to_fd): Add assertion against indexing fd_info[] with a
 value that is out of bounds.
 (sys_accept): If fd is negative, do not set up the child_process
 structure for reading.

2 files changed, 56 insertions, 30 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 46a466d060d..47a55535870 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,15 @@
+2013-02-15  Eli Zaretskii  <eliz@gnu.org>
+
+	* w32.c (sys_socket, sys_bind, sys_connect, sys_gethostname)
+	(sys_gethostbyname, sys_getservbyname, sys_getpeername)
+	(sys_shutdown, sys_setsockopt, sys_listen, sys_getsockname)
+	(sys_accept, sys_recvfrom, sys_sendto, fcntl): In case of failure,
+	make sure errno is set to an appropriate value.  (Bug#13546)
+	(socket_to_fd): Add assertion against indexing fd_info[] with a
+	value that is out of bounds.
+	(sys_accept): If fd is negative, do not set up the child_process
+	structure for reading.
+
 2013-02-14  Paul Eggert  <eggert@cs.ucla.edu>
 
 	Backport GCPRO fix from trunk (Bug#13650).
diff --git a/src/w32.c b/src/w32.c
index 214fb7fdfae..dbb090d61f9 100644
--- a/src/w32.c
+++ b/src/w32.c
@@ -5655,7 +5655,7 @@ sys_socket (int af, int type, int protocol)
 
   if (winsock_lib == NULL)
     {
-      h_errno = ENETDOWN;
+      errno = h_errno = ENETDOWN;
       return INVALID_SOCKET;
     }
 
@@ -5665,7 +5665,13 @@ sys_socket (int af, int type, int protocol)
   s = pfn_socket (af, type, protocol);
 
   if (s != INVALID_SOCKET)
-    return socket_to_fd (s);
+    {
+      int retval = socket_to_fd (s);
+
+      if (retval == -1)
+	errno = h_errno;
+      return retval;
+    }
 
   set_errno ();
   return -1;
@@ -5732,6 +5738,7 @@ socket_to_fd (SOCKET s)
 	      }
 	  }
       }
+      eassert (fd < MAXDESC);
       fd_info[fd].hnd = (HANDLE) s;
 
       /* set our own internal flags */
@@ -5770,7 +5777,7 @@ sys_bind (int s, const struct sockaddr * addr, int namelen)
 {
   if (winsock_lib == NULL)
     {
-      h_errno = ENOTSOCK;
+      errno = h_errno = ENOTSOCK;
       return SOCKET_ERROR;
     }
 
@@ -5782,7 +5789,7 @@ sys_bind (int s, const struct sockaddr * addr, int namelen)
 	set_errno ();
       return rc;
     }
-  h_errno = ENOTSOCK;
+  errno = h_errno = ENOTSOCK;
   return SOCKET_ERROR;
 }
 
@@ -5791,7 +5798,7 @@ sys_connect (int s, const struct sockaddr * name, int namelen)
 {
   if (winsock_lib == NULL)
     {
-      h_errno = ENOTSOCK;
+      errno = h_errno = ENOTSOCK;
       return SOCKET_ERROR;
     }
 
@@ -5803,7 +5810,7 @@ sys_connect (int s, const struct sockaddr * name, int namelen)
 	set_errno ();
       return rc;
     }
-  h_errno = ENOTSOCK;
+  errno = h_errno = ENOTSOCK;
   return SOCKET_ERROR;
 }
 
@@ -5837,7 +5844,7 @@ sys_gethostname (char * name, int namelen)
   if (namelen > MAX_COMPUTERNAME_LENGTH)
     return !GetComputerName (name, (DWORD *)&namelen);
 
-  h_errno = EFAULT;
+  errno = h_errno = EFAULT;
   return SOCKET_ERROR;
 }
 
@@ -5848,7 +5855,7 @@ sys_gethostbyname (const char * name)
 
   if (winsock_lib == NULL)
     {
-      h_errno = ENETDOWN;
+      errno = h_errno = ENETDOWN;
       return NULL;
     }
 
@@ -5866,7 +5873,7 @@ sys_getservbyname (const char * name, const char * proto)
 
   if (winsock_lib == NULL)
     {
-      h_errno = ENETDOWN;
+      errno = h_errno = ENETDOWN;
       return NULL;
     }
 
@@ -5882,7 +5889,7 @@ sys_getpeername (int s, struct sockaddr *addr, int * namelen)
 {
   if (winsock_lib == NULL)
     {
-      h_errno = ENETDOWN;
+      errno = h_errno = ENETDOWN;
       return SOCKET_ERROR;
     }
 
@@ -5894,7 +5901,7 @@ sys_getpeername (int s, struct sockaddr *addr, int * namelen)
 	set_errno ();
       return rc;
     }
-  h_errno = ENOTSOCK;
+  errno = h_errno = ENOTSOCK;
   return SOCKET_ERROR;
 }
 
@@ -5903,7 +5910,7 @@ sys_shutdown (int s, int how)
 {
   if (winsock_lib == NULL)
     {
-      h_errno = ENETDOWN;
+      errno = h_errno = ENETDOWN;
       return SOCKET_ERROR;
     }
 
@@ -5915,7 +5922,7 @@ sys_shutdown (int s, int how)
 	set_errno ();
       return rc;
     }
-  h_errno = ENOTSOCK;
+  errno = h_errno = ENOTSOCK;
   return SOCKET_ERROR;
 }
 
@@ -5924,7 +5931,7 @@ sys_setsockopt (int s, int level, int optname, const void * optval, int optlen)
 {
   if (winsock_lib == NULL)
     {
-      h_errno = ENETDOWN;
+      errno = h_errno = ENETDOWN;
       return SOCKET_ERROR;
     }
 
@@ -5937,7 +5944,7 @@ sys_setsockopt (int s, int level, int optname, const void * optval, int optlen)
 	set_errno ();
       return rc;
     }
-  h_errno = ENOTSOCK;
+  errno = h_errno = ENOTSOCK;
   return SOCKET_ERROR;
 }
 
@@ -5946,7 +5953,7 @@ sys_listen (int s, int backlog)
 {
   if (winsock_lib == NULL)
     {
-      h_errno = ENETDOWN;
+      errno = h_errno = ENETDOWN;
       return SOCKET_ERROR;
     }
 
@@ -5960,7 +5967,7 @@ sys_listen (int s, int backlog)
 	fd_info[s].flags |= FILE_LISTEN;
       return rc;
     }
-  h_errno = ENOTSOCK;
+  errno = h_errno = ENOTSOCK;
   return SOCKET_ERROR;
 }
 
@@ -5969,7 +5976,7 @@ sys_getsockname (int s, struct sockaddr * name, int * namelen)
 {
   if (winsock_lib == NULL)
     {
-      h_errno = ENETDOWN;
+      errno = h_errno = ENETDOWN;
       return SOCKET_ERROR;
     }
 
@@ -5981,7 +5988,7 @@ sys_getsockname (int s, struct sockaddr * name, int * namelen)
 	set_errno ();
       return rc;
     }
-  h_errno = ENOTSOCK;
+  errno = h_errno = ENOTSOCK;
   return SOCKET_ERROR;
 }
 
@@ -5990,7 +5997,7 @@ sys_accept (int s, struct sockaddr * addr, int * addrlen)
 {
   if (winsock_lib == NULL)
     {
-      h_errno = ENETDOWN;
+      errno = h_errno = ENETDOWN;
       return -1;
     }
 
@@ -6002,13 +6009,20 @@ sys_accept (int s, struct sockaddr * addr, int * addrlen)
       if (t == INVALID_SOCKET)
 	set_errno ();
       else
-	fd = socket_to_fd (t);
+	{
+	  fd = socket_to_fd (t);
+	  if (fd < 0)
+	    errno = h_errno;	/* socket_to_fd sets h_errno */
+	}
 
-      fd_info[s].cp->status = STATUS_READ_ACKNOWLEDGED;
-      ResetEvent (fd_info[s].cp->char_avail);
+      if (fd >= 0)
+	{
+	  fd_info[s].cp->status = STATUS_READ_ACKNOWLEDGED;
+	  ResetEvent (fd_info[s].cp->char_avail);
+	}
       return fd;
     }
-  h_errno = ENOTSOCK;
+  errno = h_errno = ENOTSOCK;
   return -1;
 }
 
@@ -6018,7 +6032,7 @@ sys_recvfrom (int s, char * buf, int len, int flags,
 {
   if (winsock_lib == NULL)
     {
-      h_errno = ENETDOWN;
+      errno = h_errno = ENETDOWN;
       return SOCKET_ERROR;
     }
 
@@ -6030,7 +6044,7 @@ sys_recvfrom (int s, char * buf, int len, int flags,
 	set_errno ();
       return rc;
     }
-  h_errno = ENOTSOCK;
+  errno = h_errno = ENOTSOCK;
   return SOCKET_ERROR;
 }
 
@@ -6040,7 +6054,7 @@ sys_sendto (int s, const char * buf, int len, int flags,
 {
   if (winsock_lib == NULL)
     {
-      h_errno = ENETDOWN;
+      errno = h_errno = ENETDOWN;
       return SOCKET_ERROR;
     }
 
@@ -6052,7 +6066,7 @@ sys_sendto (int s, const char * buf, int len, int flags,
 	set_errno ();
       return rc;
     }
-  h_errno = ENOTSOCK;
+  errno = h_errno = ENOTSOCK;
   return SOCKET_ERROR;
 }
 
@@ -6063,7 +6077,7 @@ fcntl (int s, int cmd, int options)
 {
   if (winsock_lib == NULL)
     {
-      h_errno = ENETDOWN;
+      errno = h_errno = ENETDOWN;
       return -1;
     }
 
@@ -6086,7 +6100,7 @@ fcntl (int s, int cmd, int options)
 	  return SOCKET_ERROR;
 	}
     }
-  h_errno = ENOTSOCK;
+  errno = h_errno = ENOTSOCK;
   return SOCKET_ERROR;
 }