Jim Meyering wrote:
>>suitable for gai_strerror. I'll have to extend lib/getaddrinfo.c a
>>little to fill in ai_canonhost and add the gai_strerror function. Would
>>that be acceptable?
>>
>>
>
>Good idea. More than `acceptable' :-)
>
>
Patch attached. I decided the reverse-lookup which used to be present
in canon-host.c when gethostbyname returned an IP address was the bug since:
- all the documentation on getaddrinfo and canonical names was
quite explicit about reverse lookups *not* being done
- canon_host used to trust getaddrinfo when it was present
- the documentation on gethostbyname also implied that the
hostname would be resolved and a test program on 1 linux
& NetBSD 1.6.1 showed that it was.
If we stumble across any systems where gethostbyname returns an IP
address when it is given a real hostname, this can be fixed then.
2005-09-05 Derek Price <[EMAIL PROTECTED]>
* modules/canon-host: Add canon-host.h. Depend on getaddrinfo. Make
LGPL.
* modules/getaddrinfo: Add link to opengroup spec. Depend on strdup.
Make canon-host require getaddrinfo.
* m4/canon-host.m4 (gl_CANON_HOST): Remove most dependencies.
AC_LIBSOURCE canon-host.h. Call...
(gl_PREREQ_CANON_HOST): ...this new function, which requires
gl_GETADDRINFO.
* m4/getaddrinfo.m4 (gl_GETADDRINFO): Compile gai_strerror when needed.
Return usable errors from canon-host.
* lib/canon-host.h: New file.
* lib/canon-host.c (canon_host): Wrap...
(canon_host_r): ...this new function, which now relies exclusively on
getaddrinfo.
(ch_strerror): New function.
(last_cherror): New global.
* lib/getaddrinfo.c: Move include of getaddrinfo.h first to test
interface.
(getaddrinfo): Add AI_CANONNAME functionality.
(freeaddrinfo): Free ai->ai_canonname when set.
This works on 1 Linux and I am installing in CVS to run it through our
compile farm. If all goes well and no one objects, I'll install it in
GNULIB in a few days.
Cheers,
Derek
--
Derek R. Price
CVS Solutions Architect
Ximbiot <http://ximbiot.com>
v: +1 717.579.6168
f: +1 717.234.3125
<mailto:[EMAIL PROTECTED]>
Index: lib/canon-host.c
===================================================================
RCS file: /cvsroot/gnulib/gnulib/lib/canon-host.c,v
retrieving revision 1.18
diff -u -p -r1.18 canon-host.c
--- lib/canon-host.c 24 Jun 2005 17:30:33 -0000 1.18
+++ lib/canon-host.c 6 Sep 2005 02:46:13 -0000
@@ -1,9 +1,9 @@
/* Host name canonicalization
- Copyright (C) 1995, 1999, 2000, 2002, 2003, 2004, 2005 Free Software
+ Copyright (C) 2005 Free Software
Foundation, Inc.
- Written by Miles Bader <[EMAIL PROTECTED]>
+ Written by Derek Price <[EMAIL PROTECTED]>.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
@@ -23,105 +23,76 @@
# include <config.h>
#endif
-#include <sys/types.h>
-#ifdef HAVE_UNISTD_H
-# include <unistd.h>
-#endif
-#include <stdlib.h>
-#include <string.h>
-#ifdef HAVE_NETDB_H
-# include <netdb.h>
-#endif
-#ifdef HAVE_SYS_SOCKET_H
-# include <sys/socket.h>
-#endif
-
-#ifdef HAVE_NETINET_IN_H
-# include <netinet/in.h>
-#endif
-#ifdef HAVE_ARPA_INET_H
-# include <arpa/inet.h>
-#endif
+#include "canon-host.h"
+#include "getaddrinfo.h"
#include "strdup.h"
-/* Returns the canonical hostname associated with HOST (allocated in a static
- buffer), or NULL if it can't be determined. */
+
+
+/* Store the last error for the single-threaded version of this function. */
+static int last_cherror;
+
+
+
+/* Single-threaded of wrapper for canon_host_r. After a NULL return, error
+ messages may be retrieved via ch_strerror().
+ */
char *
-canon_host (char const *host)
+canon_host (const char *host)
{
- char *h_addr_copy = NULL;
+ return canon_host_r (host, &last_cherror);
+}
-#if HAVE_GETADDRINFO
- {
- struct addrinfo hint = { 0, };
+
+
+/* Returns a malloc'd string containing the canonical hostname associated with
+ HOST, or NULL if a canonical name cannot be determined. On NULL return, if
+ CHERROR is not NULL, *CHERROR will be set to an error code as returned by
+ getaddrinfo(). Error codes from CHERROR may be converted to a string
+ suitable for error messages by ch_strerror_r() or gai_strerror().
+
+ WARNINGS
+ HOST must be a string representation of a resolvable name for this host.
+ Strings containing an IP address in dotted decimal notation will be
+ returned as-is, without further resolution.
+
+ The use of the word "canonical" in this context is unfortunate but
+ entrenched. The value returned by this function will be the end result
+ of the resolution of any CNAME chains in the DNS. There may only be one
+ such value for any given hostname, though the actual IP address
+ referenced by this value and the device using that IP address may each
+ actually have any number of such "canonical" hostnames. See the POSIX
+ getaddrinfo spec <http://www.opengroup.org/susv3xsh/getaddrinfo.html";>,
+ RFC 1034 <http://www.faqs.org/rfcs/rfc1034.html>, & RFC 2181
+ <http://www.faqs.org/rfcs/rfc2181.html> for more on what this confusing
+ term really refers to.
+ */
+char *
+canon_host_r (char const *host, int *cherror)
+{
+ char *retval = NULL;
+ static struct addrinfo hints = { .ai_flags = AI_CANONNAME, };
struct addrinfo *res = NULL;
- hint.ai_flags = AI_CANONNAME;
- if (getaddrinfo (host, NULL, &hint, &res) == 0)
- {
- h_addr_copy = strdup (res->ai_canonname);
+ int status;
+
+ status = getaddrinfo (host, NULL, &hints, &res);
+ if (!status)
+ {
+ retval = strdup (res->ai_canonname);
freeaddrinfo (res);
- }
- }
-#elif HAVE_GETHOSTBYNAME
- {
- struct hostent *he = gethostbyname (host);
-
- if (he)
- {
-# ifdef HAVE_GETHOSTBYADDR
- char *addr = NULL;
-
- /* Try and get an ascii version of the numeric host address. */
- switch (he->h_addrtype)
- {
-# ifdef HAVE_INET_NTOA
- case AF_INET:
- addr = inet_ntoa (*(struct in_addr *) he->h_addr);
- break;
-# endif /* HAVE_INET_NTOA */
- }
-
- if (addr && strcmp (he->h_name, addr) == 0)
- {
- /* gethostbyname has returned a string representation of the IP
- address, for example, "127.0.0.1". So now, look up the host
- name via the address. Although it may seem reasonable to look
- up the host name via the address, we must not pass `he->h_addr'
- directly to gethostbyaddr because on some systems he->h_addr
- is located in a static library buffer that is reused in the
- gethostbyaddr call. Make a copy and use that instead. */
- h_addr_copy = (char *) malloc (he->h_length);
- if (h_addr_copy == NULL)
- he = NULL;
- else
- {
- memcpy (h_addr_copy, he->h_addr, he->h_length);
- he = gethostbyaddr (h_addr_copy, he->h_length, he->h_addrtype);
- free (h_addr_copy);
- }
- }
-# endif /* HAVE_GETHOSTBYADDR */
-
- if (he)
- h_addr_copy = strdup (he->h_name);
- }
- }
-#endif /* HAVE_GETHOSTBYNAME */
+ }
+ else if (cherror)
+ *cherror = status;
- return h_addr_copy;
+ return retval;
}
-#ifdef TEST_CANON_HOST
-int
-main (int argc, char **argv)
+
+
+/* Return a string describing the last error encountered by canon_host. */
+const char *
+ch_strerror (void)
{
- int i;
- for (i = 1; i < argc; i++)
- {
- char *s = canon_host (argv[i]);
- printf ("%s: %s\n", argv[i], (s ? s : "<undef>"));
- }
- exit (0);
+ return gai_strerror (last_cherror);
}
-#endif /* TEST_CANON_HOST */
Index: lib/canon-host.h
===================================================================
RCS file: lib/canon-host.h
diff -N lib/canon-host.h
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ lib/canon-host.h 6 Sep 2005 02:46:13 -0000
@@ -0,0 +1,30 @@
+/* Host name canonicalization
+
+ Copyright (C) 2005 Free Software Foundation, Inc.
+
+ Written by Derek Price <[EMAIL PROTECTED]>
+
+ 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+#ifndef CANON_HOST_H
+# define CANON_HOST_H 1
+
+char *canon_host (char const *host);
+char *canon_host_r (char const *host, int *cherror);
+
+const char *ch_strerror (void);
+#define ch_strerror_r(cherror) gai_strerror (cherror);
+
+#endif /* !CANON_HOST_H */
Index: lib/getaddrinfo.c
===================================================================
RCS file: /cvsroot/gnulib/gnulib/lib/getaddrinfo.c,v
retrieving revision 1.3
diff -u -p -r1.3 getaddrinfo.c
--- lib/getaddrinfo.c 14 May 2005 06:03:58 -0000 1.3
+++ lib/getaddrinfo.c 6 Sep 2005 02:46:13 -0000
@@ -20,6 +20,8 @@
# include <config.h>
#endif
+#include "getaddrinfo.h"
+
/* Get calloc. */
#include <stdlib.h>
@@ -35,7 +37,7 @@
#define _(String) gettext (String)
#define N_(String) String
-#include "getaddrinfo.h"
+#include "strdup.h"
static inline bool
validate_family (int family)
@@ -67,7 +69,7 @@ getaddrinfo (const char *restrict nodena
struct hostent *he;
size_t sinlen;
- if (hints && hints->ai_flags)
+ if (hints && (hints->ai_flags & ~AI_CANONNAME))
/* FIXME: Support more flags. */
return EAI_BADFLAGS;
@@ -167,6 +169,22 @@ getaddrinfo (const char *restrict nodena
return EAI_NODATA;
}
+ if (hints && hints->flags & AI_CANONNAME)
+ {
+ char *cn;
+ if (he->h_name)
+ cn = he->h_name;
+ else
+ cn = nodename;
+
+ tmp->ai_canonname = strdup (cn);
+ if (!tmp->ai_canonname)
+ {
+ free (tmp);
+ return EAI_MEMORY;
+ }
+ }
+
tmp->ai_protocol = (hints) ? hints->ai_protocol : 0;
tmp->ai_socktype = (hints) ? hints->ai_socktype : 0;
tmp->ai_addr->sa_family = he->h_addrtype;
@@ -188,6 +206,8 @@ freeaddrinfo (struct addrinfo *ai)
cur = ai;
ai = ai->ai_next;
+
+ if (cur->ai_canonname) free (cur->ai_canonname);
free (cur);
}
}
Index: m4/canon-host.m4
===================================================================
RCS file: /cvsroot/gnulib/gnulib/m4/canon-host.m4,v
retrieving revision 1.7
diff -u -p -r1.7 canon-host.m4
--- m4/canon-host.m4 21 Mar 2005 22:06:27 -0000 1.7
+++ m4/canon-host.m4 6 Sep 2005 02:46:13 -0000
@@ -1,4 +1,4 @@
-# canon-host.m4 serial 6
+# canon-host.m4 serial 7
dnl Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -6,18 +6,11 @@ dnl with or without modifications, as lo
AC_DEFUN([gl_CANON_HOST],
[
- AC_LIBSOURCES([canon-host.c])
+ AC_LIBSOURCES([canon-host.c, canon-host.h])
AC_LIBOBJ([canon-host])
+ gl_PREREQ_CANON_HOST
+])
- dnl Prerequisites of lib/canon-host.c.
- AC_CHECK_HEADERS_ONCE(unistd.h)
- AC_CHECK_HEADERS(netdb.h sys/socket.h netinet/in.h arpa/inet.h)
-
- dnl Add any libraries as early as possible.
- dnl In particular, inet_ntoa needs -lnsl at least on Solaris 2.5.1,
- dnl so we have to add -lnsl to LIBS before checking for that function.
- AC_SEARCH_LIBS(gethostbyname, [inet nsl])
-
- dnl These come from -lnsl on Solaris 2.5.1.
- AC_CHECK_FUNCS(getaddrinfo gethostbyname gethostbyaddr inet_ntoa)
+AC_DEFUN([gl_PREREQ_CANON_HOST], [
+ AC_REQUIRE([gl_GETADDRINFO])
])
Index: m4/getaddrinfo.m4
===================================================================
RCS file: /cvsroot/gnulib/gnulib/m4/getaddrinfo.m4,v
retrieving revision 1.3
diff -u -p -r1.3 getaddrinfo.m4
--- m4/getaddrinfo.m4 10 May 2005 12:32:35 -0000 1.3
+++ m4/getaddrinfo.m4 6 Sep 2005 02:46:13 -0000
@@ -1,4 +1,4 @@
-# getaddrinfo.m4 serial 2
+# getaddrinfo.m4 serial 3
dnl Copyright (C) 2004 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -7,7 +7,7 @@ dnl with or without modifications, as lo
AC_DEFUN([gl_GETADDRINFO],
[
AC_SEARCH_LIBS(getaddrinfo, nsl socket)
- AC_REPLACE_FUNCS(getaddrinfo)
+ AC_REPLACE_FUNCS(getaddrinfo gai_strerror)
gl_PREREQ_GETADDRINFO
])
Index: modules/canon-host
===================================================================
RCS file: /cvsroot/gnulib/gnulib/modules/canon-host,v
retrieving revision 1.6
diff -u -p -r1.6 canon-host
--- modules/canon-host 21 Mar 2005 22:07:25 -0000 1.6
+++ modules/canon-host 6 Sep 2005 02:46:13 -0000
@@ -4,9 +4,11 @@ usually the host name including FQDN.
Files:
lib/canon-host.c
+lib/canon-host.h
m4/canon-host.m4
Depends-on:
+getaddrinfo
strdup
configure.ac:
@@ -15,9 +17,10 @@ gl_CANON_HOST
Makefile.am:
Include:
+#include "canon-host.h"
License:
-GPL
+LGPL
Maintainer:
Jim Meyering
Index: modules/getaddrinfo
===================================================================
RCS file: /cvsroot/gnulib/gnulib/modules/getaddrinfo,v
retrieving revision 1.3
diff -u -p -r1.3 getaddrinfo
--- modules/getaddrinfo 6 Jul 2005 15:58:47 -0000 1.3
+++ modules/getaddrinfo 6 Sep 2005 02:46:13 -0000
@@ -1,5 +1,5 @@
Description:
-Get address information.
+getaddrinfo() function: Get address information.
Files:
lib/getaddrinfo.h
@@ -12,6 +12,7 @@ Depends-on:
restrict
gettext-h
stdbool
+strdup
configure.ac:
gl_GETADDRINFO
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