Re: Exposing common type wrapping/unwrapping methods

[Ludovic Courtès]

Hi,

address@hidden (Ludovic Courtès) writes:

> 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.

Below is an updated patch that fixes two bugs in `scm_to_sockaddr ()'
and modifies `scm_connect ()', `scm_bind ()', and `scm_sendto ()'
according to Marius' suggestion.  This means that there are now two ways
to use them from Scheme, but their C API remains unchanged.  Here is an
example:

  guile> (define s (socket AF_INET SOCK_STREAM 0))
  guile> (define host (gethostbyname "www.gnu.org"))
  guile> host
  #("gnu.org" ("www.gnu.org") 2 4 (3353880842))
  guile> (define sc (connect s AF_INET 3353880842 80))
  guile> (define sa (make-socket-address AF_INET 3353880842 80))
  guile> (define s2 (socket AF_INET SOCK_STREAM 0))
  guile> (define sc2 (connect s2 sa))

Again, I only tested AF_INET addresses and I didn't try `sendto' and
`bind'.  Is there any test case out there or a program that could serve
as a test case?  Unfortunately, the old Guile-WWW available in Debian
cannot be used with Guile 1.7 because of the unavailability of
`make-shared-substring'.

I also emailed address@hidden' so that they could send me the copyright
assignment forms if that is necessary.

Thanks,
Ludovic.


ChangeLog entry for libguile:

2005-09-21  Ludovic Courtès  <address@hidden>

        * socket.c (scm_fill_sockaddr):  Added SCM_C_INLINE_KEYWORD.
        Changed the type of SIZE to `size_t'.
        (scm_connect):  Accept a socket address object as the second argument.
        (scm_bind):  Likewise.
        (scm_sendto):  Likewise.
        (scm_addr_vector):  Renamed to `_scm_from_sockaddr'.
        (scm_from_sockaddr):  New function.
        (scm_to_sockaddr):  New function.
        (scm_c_make_socket_address):  New function.
        (scm_make_socket_address):  New function.

        * socket.h:  Added declarations of the above new functions.


--- orig/libguile/socket.c
+++ mod/libguile/socket.c
@@ -664,9 +664,9 @@
    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)
+                  const char *proc, size_t *size)
 #define FUNC_NAME proc
 {
   switch (fam)
@@ -768,9 +768,9 @@
     }
 }
 #undef FUNC_NAME
-  
-SCM_DEFINE (scm_connect, "connect", 3, 0, 1,
-            (SCM sock, SCM fam, SCM address, SCM args),
+
+SCM_DEFINE (scm_connect, "connect", 2, 1, 1,
+            (SCM sock, SCM fam_or_sockaddr, SCM address, SCM args),
            "Initiate a connection from a socket using a specified address\n"
            "family to the address\n"
            "specified by @var{address} and possibly @var{args}.\n"
@@ -787,22 +787,32 @@
            "@var{args} may be up to three integers:\n"
            "port [flowinfo] [scope_id],\n"
            "where flowinfo and scope_id default to zero.\n\n"
+           "Alternatively, the second argument can be a socket address object "
+           "as returned by @code{make-socket-address}, in which case the "
+           "no additional arguments should be passed.\n\n"
            "The return value is unspecified.")
 #define FUNC_NAME s_scm_connect
 {
   int fd;
   struct sockaddr *soka;
-  int size;
+  size_t size;
 
   sock = SCM_COERCE_OUTPORT (sock);
   SCM_VALIDATE_OPFPORT (1, sock);
   fd = SCM_FPORT_FDES (sock);
-  soka = scm_fill_sockaddr (scm_to_int (fam), address, &args, 3, FUNC_NAME,
-                           &size);
+
+  if (address == SCM_UNDEFINED)
+    /* No third argument was passed to FAM_OR_SOCKADDR must actually be a
+       `socket address' object.  */
+    soka = scm_to_sockaddr (fam_or_sockaddr, &size);
+  else
+    soka = scm_fill_sockaddr (scm_to_int (fam_or_sockaddr), address,
+                             &args, 3, FUNC_NAME, &size);
+
   if (connect (fd, soka, size) == -1)
     {
       int save_errno = errno;
-      
+
       free (soka);
       errno = save_errno;
       SCM_SYSERROR;
@@ -812,8 +822,8 @@
 }
 #undef FUNC_NAME
 
-SCM_DEFINE (scm_bind, "bind", 3, 0, 1,
-            (SCM sock, SCM fam, SCM address, SCM args),
+SCM_DEFINE (scm_bind, "bind", 2, 1, 1,
+            (SCM sock, SCM fam_or_sockaddr, SCM address, SCM args),
            "Assign an address to the socket port @var{sock}.\n"
            "Generally this only needs to be done for server sockets,\n"
            "so they know where to look for incoming connections.  A socket\n"
@@ -846,22 +856,33 @@
            "may be up to three integers:\n"
            "port [flowinfo] [scope_id],\n"
            "where flowinfo and scope_id default to zero.\n\n"
+           "Alternatively, the second argument can be a socket address object "
+           "as returned by @code{make-socket-address}, in which case the "
+           "no additional arguments should be passed.\n\n"
            "The return value is unspecified.")
 #define FUNC_NAME s_scm_bind
 {
   struct sockaddr *soka;
-  int size;
+  size_t size;
   int fd;
 
   sock = SCM_COERCE_OUTPORT (sock);
   SCM_VALIDATE_OPFPORT (1, sock);
-  soka = scm_fill_sockaddr (scm_to_int (fam), address, &args, 3, FUNC_NAME,
-                           &size);
   fd = SCM_FPORT_FDES (sock);
+
+  if (address == SCM_UNDEFINED)
+    /* No third argument was passed to FAM_OR_SOCKADDR must actually be a
+       `socket address' object.  */
+    soka = scm_to_sockaddr (fam_or_sockaddr, &size);
+  else
+    soka = scm_fill_sockaddr (scm_to_int (fam_or_sockaddr), address,
+                             &args, 3, FUNC_NAME, &size);
+
+
   if (bind (fd, soka, size) == -1)
   {
     int save_errno = errno;
-      
+
     free (soka);
     errno = save_errno;
     SCM_SYSERROR;
@@ -893,8 +914,8 @@
 #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;
@@ -953,12 +974,198 @@
       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;
 }
 
+/* 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_ulong (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:
+      {
+       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
+             {
+               struct sockaddr_un *c_unix;
+
+               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
+                 {
+                   c_address = scm_malloc (sizeof (struct sockaddr_un));
+                   c_unix = (struct sockaddr_un *)c_address;
+
+                   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;
+}
+
+SCM_DEFINE (scm_make_socket_address, "make-socket-address", 2, 0, 1,
+           (SCM family, SCM address, SCM args),
+           "Return a Scheme address object that reflects @var{address}, "
+           "being an address of family @var{family}, with the "
+           "family-specific parameters @var{args} (see the description of "
+           "@code{connect} for details).")
+#define FUNC_NAME s_scm_make_socket_address
+{
+  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));
+}
+#undef FUNC_NAME
+
+
 /* 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 +1216,7 @@
   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 +1238,7 @@
   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 +1260,7 @@
   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 +1414,7 @@
   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;
 
@@ -1216,13 +1423,14 @@
 }
 #undef FUNC_NAME
 
-SCM_DEFINE (scm_sendto, "sendto", 4, 0, 1,
-            (SCM sock, SCM message, SCM fam, SCM address, SCM args_and_flags),
+SCM_DEFINE (scm_sendto, "sendto", 3, 1, 1,
+            (SCM sock, SCM message, SCM fam_or_sockaddr, SCM address, SCM 
args_and_flags),
            "Transmit the string @var{message} on the socket port\n"
            "@var{sock}.  The\n"
            "destination address is specified using the @var{fam},\n"
            "@var{address} and\n"
-           "@var{args_and_flags} arguments, in a similar way to the\n"
+           "@var{args_and_flags} arguments, or just a socket address object "
+           "returned by @code{make-socket-address}, in a similar way to the\n"
            "@code{connect} procedure.  @var{args_and_flags} contains\n"
            "the usual connection arguments optionally followed by\n"
            "a flags argument, which is a value or\n"
@@ -1241,14 +1449,26 @@
   int fd;
   int flg;
   struct sockaddr *soka;
-  int size;
+  size_t size;
 
   sock = SCM_COERCE_OUTPORT (sock);
   SCM_VALIDATE_FPORT (1, sock);
   SCM_VALIDATE_STRING (2, message);
   fd = SCM_FPORT_FDES (sock);
-  soka = scm_fill_sockaddr (scm_to_int (fam), address, &args_and_flags, 4,
-                           FUNC_NAME, &size);
+
+  if (!scm_is_number (fam_or_sockaddr))
+    {
+      /* FAM_OR_SOCKADDR must actually be a `socket address' object.  This
+        means that the following arguments, i.e. ADDRESS and those listed in
+        ARGS_AND_FLAGS, are the `MSG_' flags.  */
+      soka = scm_to_sockaddr (fam_or_sockaddr, &size);
+      if (address != SCM_UNDEFINED)
+       args_and_flags = scm_cons (address, args_and_flags);
+    }
+  else
+    soka = scm_fill_sockaddr (scm_to_int (fam_or_sockaddr), address,
+                             &args_and_flags, 3, FUNC_NAME, &size);
+
   if (scm_is_null (args_and_flags))
     flg = 0;
   else


--- orig/libguile/socket.h
+++ mod/libguile/socket.h
@@ -54,6 +54,16 @@
 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 */
 
 /*