Re: Exposing common type wrapping/unwrapping methods

[Ludovic Courtès]

Hi Marius,

Marius Vollmer <address@hidden> writes:

> Hmm, I think your patch mixes the two ways we have to express a socket
> address: one way is an argument convention used by connect, bind, and
> sendto; the other way is a vector with the relevant data inside, as
> returned by accept, getsockname, getpeername, and recvfrom!.

Right.  I followed your suggestion (with slight modifications, namely
have an ADDRESS_SIZE output parameter for functions that return a
pointer to `struct sockaddr') and updated my patch.  However, the only
thing I tested is `scm_from_sockaddr ()' on AF_INET addresses.

If this looks good to you, then I guess I can update the doc, see what
we can do with `scm_connect ()' and the likes, and submit a new patch.

Thanks,
Ludovic.



Index: socket.c
===================================================================
RCS file: /cvsroot/guile/guile/guile-core/libguile/socket.c,v
retrieving revision 1.115
diff -u -B -b -p -r1.115 socket.c
--- socket.c    10 Jul 2005 01:56:07 -0000      1.115
+++ socket.c    7 Sep 2005 09:41:40 -0000
@@ -664,7 +664,7 @@ SCM_DEFINE (scm_shutdown, "shutdown", 2,
    proc is the name of the original procedure.
    size returns the size of the structure allocated.  */
 
-static struct sockaddr *
+static SCM_C_INLINE_KEYWORD struct sockaddr *
 scm_fill_sockaddr (int fam, SCM address, SCM *args, int which_arg,
                   const char *proc, int *size)
 #define FUNC_NAME proc
@@ -893,8 +894,8 @@ SCM_DEFINE (scm_listen, "listen", 2, 0, 
 #undef FUNC_NAME
 
 /* Put the components of a sockaddr into a new SCM vector.  */
-static SCM
-scm_addr_vector (const struct sockaddr *address, int addr_size, 
+static SCM_C_INLINE_KEYWORD SCM
+_scm_from_sockaddr (const struct sockaddr *address, unsigned addr_size,
                 const char *proc)
 {
   short int fam = address->sa_family;
@@ -953,8 +954,10 @@ scm_addr_vector (const struct sockaddr *
       break;
 #endif
     default:
-      scm_misc_error (proc, "Unrecognised address family: ~A",
+      result = SCM_UNSPECIFIED;
+      scm_misc_error (proc, "unrecognised address family: ~A",
                      scm_list_1 (scm_from_int (fam)));
+
     }
   return result;
 }
@@ -959,6 +962,182 @@ scm_addr_vector (const struct sockaddr *
   return result;
 }
 
+/* The publicly-visible function.  Return a Scheme object representing
+   ADDRESS, an address of ADDR_SIZE bytes.  */
+SCM
+scm_from_sockaddr (const struct sockaddr *address, unsigned addr_size)
+{
+  return (_scm_from_sockaddr (address, addr_size, "scm_from_sockaddr"));
+}
+
+/* Convert ADDRESS, an address object returned by either
+   `scm_from_sockaddr ()' or `scm_make_socket_address ()', into its C
+   representation.  On success, a non-NULL pointer is returned and
+   ADDRESS_SIZE is updated to the actual size (in bytes) of the returned
+   address.  The result must eventually be freed using `free ()'.  */
+struct sockaddr *
+scm_to_sockaddr (SCM address, size_t *address_size)
+#define FUNC_NAME "scm_to_sockaddr"
+{
+  short int family;
+  struct sockaddr *c_address = NULL;
+
+  SCM_VALIDATE_VECTOR (1, address);
+
+  *address_size = 0;
+  family = scm_to_short (SCM_SIMPLE_VECTOR_REF (address, 0));
+
+  switch (family)
+    {
+    case AF_INET:
+      {
+       struct sockaddr_in *c_inet;
+
+       if (SCM_SIMPLE_VECTOR_LENGTH (address) != 3)
+         scm_misc_error (FUNC_NAME, "invalid inet address representation: ~A",
+                         scm_list_1 (address));
+       else
+         {
+           c_address = scm_malloc (sizeof (struct sockaddr_in));
+           c_inet = (struct sockaddr_in *)c_address;
+           c_inet->sin_addr.s_addr =
+             htonl (scm_to_long (SCM_SIMPLE_VECTOR_REF (address, 1)));
+           c_inet->sin_port =
+             htons (scm_to_ushort (SCM_SIMPLE_VECTOR_REF (address, 2)));
+
+           *address_size = sizeof (*c_inet);
+         }
+
+       break;
+      }
+
+#ifdef HAVE_IPV6
+    case AF_INET6:
+      {
+       struct sockaddr_in6 *c_inet6;
+
+       if (SCM_SIMPLE_VECTOR_LENGTH (address) != 5)
+         scm_misc_error (FUNC_NAME, "invalid inet6 address representation: ~A",
+                         scm_list_1 (address));
+       else
+         {
+           c_address = scm_malloc (sizeof (struct sockaddr_in6));
+           c_inet6 = (struct sockaddr_in6 *)c_address;
+           scm_to_ipv6 (c_inet6->sin6_addr.s6_addr, address);
+           c_inet6->sin6_port =
+             htons (scm_to_ushort (SCM_SIMPLE_VECTOR_REF (address, 2)));
+           c_inet6->sin6_flowinfo =
+             scm_to_uint32 (SCM_SIMPLE_VECTOR_REF (address, 3));
+#ifdef HAVE_SIN6_SCOPE_ID
+           c_inet6->sin6_scope_id =
+             scm_to_ulong (SCM_SIMPLE_VECTOR_REF (address, 4));
+#endif
+
+           *address_size = sizeof (*c_inet6);
+         }
+
+       break;
+      }
+#endif
+
+#ifdef HAVE_UNIX_DOMAIN_SOCKETS
+    case AF_UNIX:
+      {
+       struct sockaddr_un *c_unix;
+
+       if (SCM_SIMPLE_VECTOR_LENGTH (address) != 2)
+         scm_misc_error (FUNC_NAME, "invalid unix address representation: ~A",
+                         scm_list_1 (address));
+       else
+         {
+           SCM path;
+           size_t path_len = 0;
+
+           path = SCM_SIMPLE_VECTOR_REF (address, 1);
+           if ((!scm_is_string (path)) && (path != SCM_BOOL_F))
+             scm_misc_error (FUNC_NAME, "invalid unix address "
+                             "path: ~A", scm_list_1 (path));
+           else
+             {
+               if (path == SCM_BOOL_F)
+                 path_len = 0;
+               else
+                 path_len = scm_c_string_length (path);
+
+#ifndef UNIX_PATH_MAX
+/* We can hope that this limit will eventually vanish, at least in GNU.
+   However, currently, while glibc doesn't define `UNIX_PATH_MAX', it
+   documents it has being limited to 108 bytes.  */
+# define UNIX_PATH_MAX 108
+#endif
+               if (path_len >= UNIX_PATH_MAX)
+                 scm_misc_error (FUNC_NAME, "unix address path "
+                                 "too long: ~A", scm_list_1 (path));
+               else
+                 {
+                   if (path_len)
+                     {
+                       scm_to_locale_stringbuf (path, c_unix->sun_path,
+                                                UNIX_PATH_MAX);
+                       c_unix->sun_path[path_len - 1] = '\0';
+                     }
+                   else
+                     c_unix->sun_path[0] = '\0';
+
+                   *address_size = SUN_LEN (c_unix);
+                 }
+             }
+         }
+
+       break;
+      }
+#endif
+
+    default:
+      scm_misc_error (FUNC_NAME, "unrecognised address family: ~A",
+                     scm_list_1 (scm_from_ushort (family)));
+    }
+
+  return c_address;
+}
+#undef FUNC_NAME
+
+
+/* Return a newly-allocated `sockaddr' structure that reflects ADDRESS, being
+   an address of family FAMILY, with the family-specific parameters ARGS (see
+   the description of `connect' for details).  The returned structure may be
+   freed using `free ()'.  */
+struct sockaddr *
+scm_c_make_socket_address (SCM family, SCM address, SCM args,
+                          size_t *address_size)
+{
+  size_t size;
+  struct sockaddr *soka;
+
+  soka = scm_fill_sockaddr (scm_to_ushort (family), address, &args, 1,
+                           "scm_c_make_socket_address", &size);
+
+  return soka;
+}
+
+/* Return a Scheme address object that reflects ADDRESS, being an address of
+   family FAMILY, with the family-specific parameters ARGS (see the
+   description of `connect' for details).  */
+SCM
+scm_make_socket_address (SCM family, SCM address, SCM args)
+{
+  struct sockaddr *c_address;
+  size_t c_address_size;
+
+  c_address = scm_c_make_socket_address (family, address, args,
+                                        &c_address_size);
+  if (!c_address)
+    return SCM_BOOL_F;
+
+  return (scm_from_sockaddr (c_address, c_address_size));
+}
+
+
 /* calculate the size of a buffer large enough to hold any supported
    sockaddr type.  if the buffer isn't large enough, certain system
    calls will return a truncated address.  */
@@ -1009,7 +1188,7 @@ SCM_DEFINE (scm_accept, "accept", 1, 0, 
   if (newfd == -1)
     SCM_SYSERROR;
   newsock = SCM_SOCK_FD_TO_PORT (newfd);
-  address = scm_addr_vector (addr, addr_size, FUNC_NAME);
+  address = _scm_from_sockaddr (addr, addr_size, FUNC_NAME);
   return scm_cons (newsock, address);
 }
 #undef FUNC_NAME
@@ -1031,7 +1210,7 @@ SCM_DEFINE (scm_getsockname, "getsocknam
   fd = SCM_FPORT_FDES (sock);
   if (getsockname (fd, addr, &addr_size) == -1)
     SCM_SYSERROR;
-  return scm_addr_vector (addr, addr_size, FUNC_NAME);
+  return _scm_from_sockaddr (addr, addr_size, FUNC_NAME);
 }
 #undef FUNC_NAME
 
@@ -1053,7 +1232,7 @@ SCM_DEFINE (scm_getpeername, "getpeernam
   fd = SCM_FPORT_FDES (sock);
   if (getpeername (fd, addr, &addr_size) == -1)
     SCM_SYSERROR;
-  return scm_addr_vector (addr, addr_size, FUNC_NAME);
+  return _scm_from_sockaddr (addr, addr_size, FUNC_NAME);
 }
 #undef FUNC_NAME
 
@@ -1207,7 +1386,7 @@ SCM_DEFINE (scm_recvfrom, "recvfrom!", 2
   if (rv == -1)
     SCM_SYSERROR;
   if (addr->sa_family != AF_UNSPEC)
-    address = scm_addr_vector (addr, addr_size, FUNC_NAME);
+    address = _scm_from_sockaddr (addr, addr_size, FUNC_NAME);
   else
     address = SCM_BOOL_F;
 
Index: socket.h
===================================================================
RCS file: /cvsroot/guile/guile/guile-core/libguile/socket.h,v
retrieving revision 1.17
diff -u -B -b -p -r1.17 socket.h
--- socket.h    23 May 2005 19:57:21 -0000      1.17
+++ socket.h    7 Sep 2005 09:41:40 -0000
@@ -54,6 +54,16 @@ SCM_API SCM scm_recvfrom (SCM sockfd, SC
 SCM_API SCM scm_sendto (SCM sockfd, SCM message, SCM fam, SCM address, SCM 
args_and_flags);
 SCM_API void scm_init_socket (void);
 
+/* Wrapping/unwrapping address objects.  */
+struct sockaddr;
+SCM_API SCM scm_from_sockaddr (const struct sockaddr *address,
+                              unsigned addr_size);
+SCM_API struct sockaddr *scm_to_sockaddr (SCM address, size_t *adress_size);
+SCM_API struct sockaddr *scm_c_make_socket_address (SCM family, SCM address,
+                                                   SCM args,
+                                                   size_t *address_size);
+SCM_API SCM scm_make_socket_address (SCM family, SCM address, SCM args);
+
 #endif  /* SCM_SOCKET_H */
 
 /*