[Bug-gnulib] Re: getaddrinfo

[Simon Josefsson]

Paul Eggert <address@hidden> writes:

>> I have a vague recollection that using CPP #if's inside a C statement
>> in this way was not valid.
>
> It's not valid to use #if's like this inside a macro call.

Ah, that was it.  Thanks.

Bruno Haible <address@hidden> writes:

>> #ifndef PF_INET
>> # define PF_INET 0.5
>> #endif
>> #ifndef PF_INET6
>> # define PF_INET6 0.5
>> #endif
>>
>>   if (hints
>>       && hints->ai_family != PF_INET
>>       && hints->ai_family != PF_INET6
>>       && hints->ai_family != PF_UNSPEC)
>
> not only obfuscates the intent of code (it looks aesthetically better
> but is more confusing), but also leaves a useless floating-point
> computation in the code path. (Yes, gcc does not eliminate the
> useless comparisons.)

I agree with Bruno here, while the 0.5 approach might be a neat trick,
it is (to me) far from a idiomatic construct that simplify reading,
rather I think it is confusing for a casual reader.

> If you want to avoid #if conditionals inside expressions, I suggest to
> change the expression into multiple statements:
>
> static inline bool
> validate_family (int family)
> {
> #if HAVE_IPV4
>   if (family == PF_INET)
>     return true;
> #endif
> #if HAVE_IPV6
>   if (family == PF_INET6)
>     return true;
> #endif
>   if (family == PF_UNSPEC)
>     return true;
>   return false;
> }
>
>   if (hints && !validate_family (hints->ai_family))
>     return EAI_FAMILY;

I'm using this now.

I have installed the patch below.

Thanks.

Index: ChangeLog
===================================================================
RCS file: /cvsroot/gnulib/gnulib/ChangeLog,v
retrieving revision 1.215
diff -u -p -r1.215 ChangeLog
--- ChangeLog   10 Nov 2004 08:50:25 -0000      1.215
+++ ChangeLog   10 Nov 2004 14:52:40 -0000
@@ -1,3 +1,10 @@
+2004-11-08  Simon Josefsson  <address@hidden>
+
+       * MODULES.html.sh (Support for systems lacking POSIX:2001): Add
+       getaddrinfo.
+
+       * modules/getaddrinfo: New file.
+
 2004-11-10  Jim Meyering  <address@hidden>
 
        * modules/closeout (Depends-on): Remove fpending.
Index: MODULES.html.sh
===================================================================
RCS file: /cvsroot/gnulib/gnulib/MODULES.html.sh,v
retrieving revision 1.66
diff -u -p -r1.66 MODULES.html.sh
--- MODULES.html.sh     11 Oct 2004 13:08:55 -0000      1.66
+++ MODULES.html.sh     10 Nov 2004 14:52:40 -0000
@@ -1730,6 +1730,7 @@ func_all_modules ()
   func_module chown
   func_module dup2
   func_module ftruncate
+  func_module getaddrinfo
   func_module getcwd
   func_module getgroups
   func_module gethostname
Index: lib/ChangeLog
===================================================================
RCS file: /cvsroot/gnulib/gnulib/lib/ChangeLog,v
retrieving revision 1.741
diff -u -p -r1.741 ChangeLog
--- lib/ChangeLog       10 Nov 2004 08:48:50 -0000      1.741
+++ lib/ChangeLog       10 Nov 2004 14:52:41 -0000
@@ -1,3 +1,7 @@
+2004-11-08  Simon Josefsson  <address@hidden>
+
+       * getaddrinfo.h, getaddrinfo.c: New file.
+
 2004-11-10  Jim Meyering  <address@hidden>
 
        Ensure that no close failure goes unreported.
Index: lib/gai_strerror.c
===================================================================
RCS file: lib/gai_strerror.c
diff -N lib/gai_strerror.c
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ lib/gai_strerror.c  10 Nov 2004 14:52:41 -0000
@@ -0,0 +1,72 @@
+/* Copyright (C) 1997, 2001, 2002, 2004 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Philip Blundell <address@hidden>, 1997.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <stdio.h>
+#include <netdb.h>
+
+#ifdef _LIBC
+# include <libintl.h>
+#else
+# include "getaddrinfo.h"
+# include "gettext.h"
+# define _(String) gettext (String)
+# define N_(String) String
+#endif
+
+static struct
+  {
+    int code;
+    const char *msg;
+  }
+values[] =
+  {
+    { EAI_ADDRFAMILY, N_("Address family for hostname not supported") },
+    { EAI_AGAIN, N_("Temporary failure in name resolution") },
+    { EAI_BADFLAGS, N_("Bad value for ai_flags") },
+    { EAI_FAIL, N_("Non-recoverable failure in name resolution") },
+    { EAI_FAMILY, N_("ai_family not supported") },
+    { EAI_MEMORY, N_("Memory allocation failure") },
+    { EAI_NODATA, N_("No address associated with hostname") },
+    { EAI_NONAME, N_("Name or service not known") },
+    { EAI_SERVICE, N_("Servname not supported for ai_socktype") },
+    { EAI_SOCKTYPE, N_("ai_socktype not supported") },
+    { EAI_SYSTEM, N_("System error") },
+#ifdef __USE_GNU
+    { EAI_INPROGRESS, N_("Processing request in progress") },
+    { EAI_CANCELED, N_("Request canceled") },
+    { EAI_NOTCANCELED, N_("Request not canceled") },
+    { EAI_ALLDONE, N_("All requests done") },
+    { EAI_INTR, N_("Interrupted by a signal") },
+    { EAI_IDN_ENCODE, N_("Parameter string not correctly encoded") }
+#endif
+  };
+
+const char *
+gai_strerror (int code)
+{
+  size_t i;
+  for (i = 0; i < sizeof (values) / sizeof (values[0]); ++i)
+    if (values[i].code == code)
+      return _(values[i].msg);
+
+  return _("Unknown error");
+}
+#ifdef _LIBC
+libc_hidden_def (gai_strerror)
+#endif
Index: lib/getaddrinfo.h
===================================================================
RCS file: lib/getaddrinfo.h
diff -N lib/getaddrinfo.h
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ lib/getaddrinfo.h   10 Nov 2004 14:52:41 -0000
@@ -0,0 +1,90 @@
+/* Get address information.
+   Copyright (C) 1996-2002, 2003, 2004 Free Software Foundation, Inc.
+   Contributed by Simon Josefsson <address@hidden>.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+#ifndef GETADDRINFO_H
+# define GETADDRINFO_H
+
+/* Get getaddrinfo declarations, if available. */
+# include <sys/socket.h>
+# include <netdb.h>
+
+# if defined HAVE_GETADDRINFO && !HAVE_GETADDRINFO
+
+/* Get socklen_t, struct sockaddr. */
+#  include <sys/types.h>
+
+/* Structure to contain information about address of a service provider.  */
+struct addrinfo
+{
+  int ai_flags;                        /* Input flags.  */
+  int ai_family;               /* Protocol family for socket.  */
+  int ai_socktype;             /* Socket type.  */
+  int ai_protocol;             /* Protocol for socket.  */
+  socklen_t ai_addrlen;                /* Length of socket address.  */
+  struct sockaddr *ai_addr;    /* Socket address for socket.  */
+  char *ai_canonname;          /* Canonical name for service location.  */
+  struct addrinfo *ai_next;    /* Pointer to next in list.  */
+};
+
+/* Possible values for `ai_flags' field in `addrinfo' structure.  */
+# define AI_PASSIVE    0x0001  /* Socket address is intended for `bind'.  */
+# define AI_CANONNAME  0x0002  /* Request for canonical name.  */
+# define AI_NUMERICHOST        0x0004  /* Don't use name resolution.  */
+# define AI_V4MAPPED   0x0008  /* IPv4 mapped addresses are acceptable.  */
+# define AI_ALL                0x0010  /* Return IPv4 mapped and IPv6 
addresses.  */
+# define AI_ADDRCONFIG 0x0020  /* Use configuration of this host to choose
+                                  returned address type..  */
+
+/* Error values for `getaddrinfo' function.  */
+# define EAI_BADFLAGS    -1    /* Invalid value for `ai_flags' field.  */
+# define EAI_NONAME      -2    /* NAME or SERVICE is unknown.  */
+# define EAI_AGAIN       -3    /* Temporary failure in name resolution.  */
+# define EAI_FAIL        -4    /* Non-recoverable failure in name res.  */
+# define EAI_NODATA      -5    /* No address associated with NAME.  */
+# define EAI_FAMILY      -6    /* `ai_family' not supported.  */
+# define EAI_SOCKTYPE    -7    /* `ai_socktype' not supported.  */
+# define EAI_SERVICE     -8    /* SERVICE not supported for `ai_socktype'.  */
+# define EAI_ADDRFAMILY          -9    /* Address family for NAME not 
supported.  */
+# define EAI_MEMORY      -10   /* Memory allocation failure.  */
+# define EAI_SYSTEM      -11   /* System error returned in `errno'.  */
+# define EAI_OVERFLOW    -12   /* Argument buffer overflow.  */
+# ifdef __USE_GNU
+#  define EAI_INPROGRESS  -100 /* Processing request in progress.  */
+#  define EAI_CANCELED   -101  /* Request canceled.  */
+#  define EAI_NOTCANCELED -102 /* Request not canceled.  */
+#  define EAI_ALLDONE    -103  /* All requests done.  */
+#  define EAI_INTR       -104  /* Interrupted by a signal.  */
+#  define EAI_IDN_ENCODE  -105 /* IDN encoding failed.  */
+# endif
+
+/* Translate name of a service location and/or a service name to set of
+   socket addresses.  */
+extern int getaddrinfo (const char *restrict nodename,
+                       const char *restrict servname,
+                       const struct addrinfo *restrict hints,
+                       struct addrinfo **restrict res);
+
+/* Free `addrinfo' structure AI including associated storage.  */
+extern void freeaddrinfo (struct addrinfo *ai);
+
+/* Convert error return from getaddrinfo() to a string.  */
+extern const char *gai_strerror (int ecode);
+
+# endif
+
+#endif /* GETADDRINFO_H */
Index: lib/getaddrinfo.c
===================================================================
RCS file: lib/getaddrinfo.c
diff -N lib/getaddrinfo.c
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ lib/getaddrinfo.c   10 Nov 2004 14:52:41 -0000
@@ -0,0 +1,195 @@
+/* Get address information (partial implementation).
+   Copyright (C) 1997, 2001, 2002, 2004 Free Software Foundation, Inc.
+   Contributed by Simon Josefsson <address@hidden>.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+#if HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+/* Get calloc. */
+#include <stdlib.h>
+
+/* Get memcpy. */
+#include <string.h>
+
+/* Get struct hostent. */
+#include <netdb.h>
+
+#include <stdbool.h>
+
+#include "gettext.h"
+#define _(String) gettext (String)
+#define N_(String) String
+
+#include "getaddrinfo.h"
+
+static inline bool
+validate_family (int family)
+{
+  /* FIXME: Support more families. */
+#if HAVE_IPV4
+     if (family == PF_INET)
+       return true;
+#endif
+#if HAVE_IPV6
+     if (family == PF_INET6)
+       return true;
+#endif
+     if (family == PF_UNSPEC)
+       return true;
+     return false;
+}
+
+/* Translate name of a service location and/or a service name to set of
+   socket addresses. */
+int
+getaddrinfo (const char *restrict nodename,
+            const char *restrict servname,
+            const struct addrinfo *restrict hints,
+            struct addrinfo **restrict res)
+{
+  struct addrinfo *tmp;
+  struct servent *se;
+  struct hostent *he;
+  size_t sinlen;
+
+  if (hints && hints->ai_flags)
+    /* FIXME: Support more flags. */
+    return EAI_BADFLAGS;
+
+  if (hints && !validate_family (hints->ai_family))
+    return EAI_FAMILY;
+
+  if (hints && hints->ai_socktype)
+    /* FIXME: Support more socket types. */
+    return EAI_SOCKTYPE;
+
+  if (hints &&
+      hints->ai_protocol != SOCK_STREAM && hints->ai_protocol != SOCK_DGRAM)
+    /* FIXME: Support other protocols. */
+    return EAI_SERVICE;                /* FIXME: Better return code? */
+
+  if (!nodename)
+    /* FIXME: Support server bind mode. */
+    return EAI_NONAME;
+
+  if (servname)
+    {
+      const char *proto =
+       (hints && hints->ai_protocol == SOCK_DGRAM) ? "udp" : "tcp";
+
+      /* FIXME: Use getservbyname_r if available. */
+      se = getservbyname (servname, proto);
+
+      if (!se)
+       return EAI_SERVICE;
+    }
+
+  /* FIXME: Use gethostbyname_r if available. */
+  he = gethostbyname (nodename);
+  if (!he || he->h_addr_list[0] == NULL)
+    return EAI_NONAME;
+
+  switch (he->h_addrtype)
+    {
+#if HAVE_IPV6
+    case PF_INET6:
+      sinlen = sizeof (struct sockaddr_in6);
+      break;
+#endif
+
+#if HAVE_IPV4
+    case PF_INET:
+      sinlen = sizeof (struct sockaddr_in);
+      break;
+#endif
+
+    default:
+      return EAI_NODATA;
+    }
+
+  tmp = calloc (1, sizeof (*tmp) + sinlen);
+  if (!tmp)
+    return EAI_MEMORY;
+
+  switch (he->h_addrtype)
+    {
+#if HAVE_IPV6
+    case PF_INET6:
+      {
+       struct sockaddr_in6 *sinp = (void *) tmp + sizeof (*tmp);
+
+       if (se)
+         sinp->sin6_port = se->s_port;
+
+       if (he->h_length != sizeof (sinp->sin6_addr))
+         return EAI_SYSTEM; /* FIXME: Better return code?  Set errno? */
+
+       memcpy (&sinp->sin6_addr, he->h_addr_list[0], he->h_length);
+
+       tmp->ai_addr = (struct sockaddr *) sinp;
+       tmp->ai_addrlen = sinlen;
+      }
+      break;
+#endif
+
+#if HAVE_IPV4
+    case PF_INET:
+      {
+       struct sockaddr_in *sinp = (void *) tmp + sizeof (*tmp);
+
+       if (se)
+         sinp->sin_port = se->s_port;
+
+       if (he->h_length != sizeof (sinp->sin_addr))
+         return EAI_SYSTEM; /* FIXME: Better return code?  Set errno? */
+
+       memcpy (&sinp->sin_addr, he->h_addr_list[0], he->h_length);
+
+       tmp->ai_addr = (struct sockaddr *) sinp;
+       tmp->ai_addrlen = sinlen;
+      }
+      break;
+#endif
+
+    default:
+      free (tmp);
+      return EAI_NODATA;
+    }
+
+  tmp->ai_addr->sa_family = he->h_addrtype;
+
+  /* FIXME: If more than one address, create linked list of addrinfo's. */
+
+  *res = tmp;
+
+  return 0;
+}
+
+/* Free `addrinfo' structure AI including associated storage.  */
+void
+freeaddrinfo (struct addrinfo *ai)
+{
+  while (ai)
+    {
+      struct addrinfo *cur;
+
+      cur = ai;
+      ai = ai->ai_next;
+      free (cur);
+    }
+}
Index: m4/ChangeLog
===================================================================
RCS file: /cvsroot/gnulib/gnulib/m4/ChangeLog,v
retrieving revision 1.591
diff -u -p -r1.591 ChangeLog
--- m4/ChangeLog        9 Nov 2004 20:54:49 -0000       1.591
+++ m4/ChangeLog        10 Nov 2004 14:52:41 -0000
@@ -1,3 +1,7 @@
+2004-11-08  Simon Josefsson  <address@hidden>
+
+       * getaddrinfo.m4: New file.
+
 2004-11-09  Paul Eggert  <address@hidden>
 
        * strftime.m4 (_gl_STRFTIME_PREREQS): Remove.  Move its body to
Index: m4/getaddrinfo.m4
===================================================================
RCS file: m4/getaddrinfo.m4
diff -N m4/getaddrinfo.m4
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ m4/getaddrinfo.m4   10 Nov 2004 14:52:41 -0000
@@ -0,0 +1,20 @@
+# getaddrinfo.m4 serial 1
+dnl Copyright (C) 2004 Free Software Foundation, Inc.
+dnl This file is free software, distributed under the terms of the GNU
+dnl General Public License.  As a special exception to the GNU General
+dnl Public License, this file may be distributed as part of a program
+dnl that contains a configuration script generated by Autoconf, under
+dnl the same distribution terms as the rest of that program.
+
+AC_DEFUN([gl_GETADDRINFO],
+[
+  AC_REPLACE_FUNCS(getaddrinfo)
+  gl_PREREQ_GETADDRINFO
+])
+
+# Prerequisites of lib/getaddrinfo.h and lib/getaddrinfo.c.
+AC_DEFUN([gl_PREREQ_GETADDRINFO], [
+  AC_REQUIRE([gl_C_RESTRICT])
+  AC_REQUIRE([gl_SOCKET_FAMILIES])
+  AC_REQUIRE([AC_C_INLINE])
+])
Index: modules/getaddrinfo
===================================================================
RCS file: modules/getaddrinfo
diff -N modules/getaddrinfo
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ modules/getaddrinfo 10 Nov 2004 14:52:41 -0000
@@ -0,0 +1,26 @@
+Description:
+Get address information.
+
+Files:
+lib/getaddrinfo.h
+lib/getaddrinfo.c
+lib/gai_strerror.c
+m4/getaddrinfo.m4
+m4/sockpfaf.m4
+
+Depends-on:
+restrict
+gettext
+stdbool
+
+configure.ac:
+gl_GETADDRINFO
+
+Makefile.am:
+lib_SOURCES += getaddrinfo.h
+
+Include:
+"getaddrinfo.h"
+
+Maintainer:
+Simon Josefsson