[Chris, can you have a look into Pierre's dup_ent changes? Thanks.]
Hi Pierre,
On Mar 2 20:36, Pierre A. Humblet wrote:
> Corinna,
>
> OK, here we go again.
>
> This version calls res_query and all the work is done in net.cc.
First of all, thanks for doing that.
> - Because of the above, asm/byteorder.h doesn't get pulled in either,
> and I couldn't use
> some ntoh macros (see memcpy4to6).
> - I could have included asm/byteorder separately but that causes
> conflicts with the local ntoh
> definitions in net.cc.
I fixed that by moving the definitions of ntohl and friends to the end
of the file and by defining them according to the definitions in
asm/byteorder.h. That's what POSIX demands anyway.
> - Because arpa/nameser.h is now pulled in, IN6ADDRSZ etc are now
> defined, but in a way different
> from done in the snippet of code cut & pasted from bind. I didn't want
> to change that piece (in
> case you want to keep in intact for some reason) and I ended up
> undefining IN6ADDRSZ etc .
I removed thatto use the definitions from nameser_compat.h. They are
equivalent anyway.
> - There is a new helper function dn_length1 which logically belongs in
> minires.c, although it shouldn't
> be exported by the dll. However if I place it in minires.c, then the
> linker doesn't find it.
You missed to define it as a `extern "C" function.
> Fixing that probably involves some Makefile magic.
No, it's sufficent to define it as extern "C". I changed your patch
so that dn_length1 is now declared in the `extern "C" declaration
block at the start of net.cc and I moved the function into minires.c.
> - I structured the code with a helper function gethostby_helper. That
> will make it very easy to support
> a gethostbyaddress some day, if needed.
> - The helper function avoids using dup_ent (there is enough copying
> already). I created a new
> realloc_ent function, and call it from both dup_ent and the helper.
> That caused minor
> changes in the 4 versions of dup_ent, and I don't know exactly what
> format to use in the ChangeLog
The patch looks good to me. I only changed the definition of realloc_ent
to be a static function.
> - This is much more complex than the first way of doing things. Needs
> testing!
> - The patch is long, see the attachment. There is also a test program
> attached.
All my usual network applications are still working fine.
I attached the entire patch again with my changes. I had to change the
gethostby_helper function to define some of the variables at the start
of the function, othewise gcc complained about jumps to a label crossing
variable initializations. The bump of the API minor number in
include/cygwin/version.h was missing. I also tweaked the formatting a bit.
The ChangeLog entry is the same as in the OP, except for the additional
reference to include/cygwin/version.h. Please have a look.
Chris, the dup_ent code is yours. Can you have a look if the realloc_ent
changes are ok with you?
Thanks,
Corinna
* net.cc: define _CYGWIN_IN_H and include resolv.h.
(realloc_ent): New function.
(dup_ent): Remove dst argument and call realloc_ent.
(memcpy4to6): New function.
(dn_length1): New function.
(gethostby_helper): New function.
(gethostbyname2): New function.
* cygwin.din: Export gethostbyname2.
* libc/minires.c (get_options): Look for "inet6" and apply bounds
to "retry" and "retrans".
(res_ninit): Set the default options at the beginning.
(dn_expand): Fix "off by one".
* include/cygwin/version.h: Bump API minor number.
Index: cygwin.din
===================================================================
RCS file: /cvs/src/src/winsup/cygwin/cygwin.din,v
retrieving revision 1.202
diff -u -p -r1.202 cygwin.din
--- cygwin.din 19 Feb 2009 09:22:51 -0000 1.202
+++ cygwin.din 3 Mar 2009 11:54:11 -0000
@@ -635,6 +635,7 @@ _getgroups = getgroups SIGFE
_getgroups32 = getgroups32 SIGFE
gethostbyaddr = cygwin_gethostbyaddr SIGFE
gethostbyname = cygwin_gethostbyname SIGFE
+gethostbyname2 SIGFE
gethostid SIGFE
gethostname = cygwin_gethostname SIGFE
_gethostname = cygwin_gethostname SIGFE
Index: net.cc
===================================================================
RCS file: /cvs/src/src/winsup/cygwin/net.cc,v
retrieving revision 1.249
diff -u -p -r1.249 net.cc
--- net.cc 3 Mar 2009 11:44:17 -0000 1.249
+++ net.cc 3 Mar 2009 11:54:12 -0000
@@ -1,7 +1,7 @@
/* net.cc: network-related routines.
Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
- 2005, 2006, 2007 Red Hat, Inc.
+ 2005, 2006, 2007, 2008, 2009 Red Hat, Inc.
This file is part of Cygwin.
@@ -43,6 +43,8 @@ details. */
#include "cygwin/in6.h"
#include "ifaddrs.h"
#include "tls_pbuf.h"
+#define _CYGWIN_IN_H
+#include <resolv.h>
extern "C"
{
@@ -53,6 +55,9 @@ extern "C"
int sscanf (const char *, const char *, ...);
int cygwin_inet_aton(const char *, struct in_addr *);
const char *cygwin_inet_ntop (int, const void *, char *, socklen_t);
+ int dn_length1(const unsigned char *, const unsigned char *,
+ const unsigned char *);
+
} /* End of "C" section */
const struct in6_addr in6addr_any = {{IN6ADDR_ANY_INIT}};
@@ -264,6 +269,34 @@ struct pservent
static const char *entnames[] = {"host", "proto", "serv"};
+static unionent *
+realloc_ent (int sz, unionent::struct_type type)
+{
+ /* Allocate the storage needed. Allocate a rounded size to attempt to force
+ reuse of this buffer so that a poorly-written caller will not be using
+ a freed buffer. */
+ unsigned rsz = 256 * ((sz + 255) / 256);
+ unionent * dst, * ptr;
+ switch (type)
+ {
+ case unionent::t_hostent:
+ dst = _my_tls.locals.hostent_buf;
+ break;
+ case unionent::t_protoent:
+ dst =_my_tls.locals.protoent_buf;
+ break;
+ case unionent::t_servent:
+ dst =_my_tls.locals.servent_buf;
+ break;
+ default:
+ return NULL;
+ }
+ ptr = (unionent *) realloc (dst, rsz);
+ if (ptr)
+ dst = ptr;
+ return ptr;
+}
+
/* Generic "dup a {host,proto,serv}ent structure" function.
This is complicated because we need to be able to free the
structure at any point and we can't rely on the pointer contents
@@ -278,12 +311,8 @@ static void *
#else
static inline void *
#endif
-dup_ent (unionent *&dst, unionent *src, unionent::struct_type type)
+dup_ent (unionent *src, unionent::struct_type type)
{
- if (dst)
- debug_printf ("old %sent structure \"%s\" %p\n", entnames[type],
- dst->name, dst);
-
if (!src)
{
set_winsock_errno ();
@@ -310,7 +339,7 @@ dup_ent (unionent *&dst, unionent *src,
break;
}
- /* Every *ent begins with a name. Calculate it's length. */
+ /* Every *ent begins with a name. Calculate its length. */
int namelen = strlen_round (src->name);
sz = struct_sz + namelen;
@@ -355,11 +384,7 @@ dup_ent (unionent *&dst, unionent *src,
}
}
- /* Allocate the storage needed. Allocate a rounded size to attempt to force
- reuse of this buffer so that a poorly-written caller will not be using
- a freed buffer. */
- unsigned rsz = 256 * ((sz + 255) / 256);
- dst = (unionent *) realloc (dst, rsz);
+ unionent *dst = realloc_ent (sz, type);
if (dst)
{
@@ -425,19 +450,19 @@ dup_ent (unionent *&dst, unionent *src,
static inline hostent *
dup_ent (hostent *src)
{
- return (hostent *) dup_ent (_my_tls.locals.hostent_buf, (unionent *) src,
unionent::t_hostent);
+ return (hostent *) dup_ent ((unionent *) src, unionent::t_hostent);
}
static inline protoent *
dup_ent (protoent *src)
{
- return (protoent *) dup_ent (_my_tls.locals.protoent_buf, (unionent *) src,
unionent::t_protoent);
+ return (protoent *) dup_ent ((unionent *) src, unionent::t_protoent);
}
static inline servent *
dup_ent (servent *src)
{
- return (servent *) dup_ent (_my_tls.locals.servent_buf, (unionent *) src,
unionent::t_servent);
+ return (servent *) dup_ent ((unionent *) src, unionent::t_servent);
}
/* exported as getprotobyname: standards? */
@@ -857,6 +882,287 @@ cygwin_gethostbyaddr (const char *addr,
return res;
}
+static void
+memcpy4to6 (char *dst, const u_char *src)
+{
+ const unsigned int h[] = {0, 0, htonl (0xFFFF)};
+ memcpy (dst, h, 12);
+ memcpy (dst + 12, src, NS_INADDRSZ);
+}
+
+static hostent *
+gethostby_helper (const char *name, const int af, const int type,
+ const int addrsize_in, const int addrsize_out)
+{
+ /* Get the data from the name server */
+ const int maxcount = 3;
+ int old_errno, ancount = 0, anlen = 1024, msgsize = 0;
+ u_char *ptr, *msg = NULL;
+ int sz;
+ hostent *ret;
+ char *string_ptr;
+
+ while ((anlen > msgsize) && (ancount++ < maxcount))
+ {
+ msgsize = anlen;
+ ptr = (u_char *) realloc (msg, msgsize);
+ if (ptr == NULL )
+ {
+ old_errno = errno;
+ free (msg);
+ set_errno (old_errno);
+ h_errno = NETDB_INTERNAL;
+ return NULL;
+ }
+ msg = ptr;
+ anlen = res_search (name, ns_c_in, type, msg, msgsize);
+ }
+
+ if (ancount >= maxcount)
+ {
+ free (msg);
+ h_errno = NO_RECOVERY;
+ return NULL;
+ }
+ if (anlen < 0) /* errno and h_errno are set */
+ {
+ old_errno = errno;
+ free (msg);
+ set_errno (old_errno);
+ return NULL;
+ }
+ u_char *eomsg = msg + anlen - 1;
+
+
+ /* We scan the answer records to determine the required memory size.
+ They can be corrupted and we don't fully trust that the message
+ follows the standard exactly. glibc applies some checks that
+ we emulate.
+ The answers are copied in the hostent structure in a second scan.
+ To simplify the second scan we store information as follows:
+ - "class" is replaced by the compressed name size
+ - the first 16 bits of the "ttl" store the expanded name size + 1
+ - the last 16 bits of the "ttl" store the offset to the next valid record.
+ Note that "type" is rewritten in host byte order. */
+
+ class record {
+ public:
+ unsigned type: 16; // type
+ unsigned complen: 16; // class or compressed length
+ unsigned namelen1: 16; // expanded length (with final 0)
+ unsigned next_o: 16; // offset to next valid
+ unsigned size: 16; // data size
+ u_char data[]; // data
+ record * next () { return (record *) (((char *) this) + next_o); }
+ void set_next ( record * nxt) { next_o = ((char *) nxt) - ((char *) this);
}
+ u_char * name () { return (u_char *) (((char *) this) - complen); }
+ };
+
+ record * anptr = NULL, * prevptr = NULL, * curptr;
+ int i, alias_count = 0, string_size = 0, address_count = 0;
+ int complen, namelen1 = 0, address_len = 0, antype, anclass, ansize;
+
+ /* Get the count of answers */
+ ancount = ntohs (((HEADER *) msg)->ancount);
+
+ /* Skip the question, it was verified by res_send */
+ ptr = msg + sizeof (HEADER);
+ if ((complen = dn_skipname (ptr, eomsg)) < 0)
+ goto corrupted;
+ /* Point to the beginning of the answer section */
+ ptr += complen + NS_QFIXEDSZ;
+
+ /* Scan the answer records to determine the sizes */
+ for (i = 0; i < ancount; i++, ptr = curptr->data + ansize)
+ {
+ if ((complen = dn_skipname (ptr, eomsg)) < 0)
+ goto corrupted;
+
+ curptr = (record *) (ptr + complen);
+ antype = ntohs (curptr->type);
+ anclass = ntohs (curptr->complen);
+ ansize = ntohs (curptr->size);
+ /* Class must be internet */
+ if (anclass != ns_c_in)
+ continue;
+
+ curptr->complen = complen;
+ if ((namelen1 = dn_length1 (msg, eomsg, curptr-> name())) <= 0)
+ goto corrupted;
+
+ if (antype == ns_t_cname)
+ {
+ alias_count++;
+ string_size += namelen1;
+ }
+ else if (antype == type)
+ {
+ ansize = ntohs (curptr->size);
+ if (ansize != addrsize_in)
+ continue;
+ if (address_count == 0)
+ {
+ address_len = namelen1;
+ string_size += namelen1;
+ }
+ else if (address_len != namelen1)
+ continue;
+ address_count++;
+ }
+ /* Update the records */
+ curptr->type = antype; /* Host byte order */
+ curptr->namelen1 = namelen1;
+ if (! anptr)
+ anptr = prevptr = curptr;
+ else
+ {
+ prevptr->set_next (curptr);
+ prevptr = curptr;
+ }
+ }
+
+ /* If there is no address, quit */
+ if (address_count == 0)
+ {
+ free (msg);
+ h_errno = NO_DATA;
+ return NULL;
+ }
+
+ /* Determine the total size */
+ sz = DWORD_round (sizeof(hostent))
+ + sizeof (char *) * (alias_count + address_count + 2)
+ + string_size
+ + address_count * addrsize_out;
+
+ ret = (hostent *) realloc_ent (sz, unionent::t_hostent);
+ if (! ret)
+ {
+ old_errno = errno;
+ free (msg);
+ set_errno (old_errno);
+ h_errno = NETDB_INTERNAL;
+ return NULL;
+ }
+
+ ret->h_addrtype = af;
+ ret->h_length = addrsize_out;
+ ret->h_aliases = (char **) (((char *) ret) + DWORD_round (sizeof(hostent)));
+ ret->h_addr_list = ret->h_aliases + alias_count + 1;
+ string_ptr = (char *) (ret->h_addr_list + address_count + 1);
+
+ /* Rescan the answers */
+ ancount = alias_count + address_count; /* Valid records */
+ alias_count = address_count = 0;
+
+ for (i = 0, curptr = anptr; i < ancount; i++, curptr = curptr->next ())
+ {
+ antype = curptr->type;
+ if (antype == ns_t_cname)
+ {
+ complen = dn_expand (msg, eomsg, curptr->name (), string_ptr,
string_size);
+#ifdef DEBUGGING
+ if (complen != curptr->complen)
+ go to debugging;
+#endif
+ ret->h_aliases[alias_count++] = string_ptr;
+ namelen1 = curptr->namelen1;
+ string_ptr += namelen1;
+ string_size -= namelen1;
+ continue;
+ }
+ if (antype == type)
+ {
+ if (address_count == 0)
+ {
+ complen = dn_expand (msg, eomsg, curptr->name(), string_ptr,
string_size);
+#ifdef DEBUGGING
+ if (complen != curptr->complen)
+ go to debugging;
+#endif
+ ret->h_name = string_ptr;
+ namelen1 = curptr->namelen1;
+ string_ptr += namelen1;
+ string_size -= namelen1;
+ }
+ ret->h_addr_list[address_count++] = string_ptr;
+ if (addrsize_in != addrsize_out)
+ memcpy4to6 (string_ptr, curptr->data);
+ else
+ memcpy (string_ptr, curptr->data, addrsize_in);
+ string_ptr += addrsize_out;
+ string_size -= addrsize_out;
+ continue;
+ }
+#ifdef DEBUGGING
+ /* Should not get here */
+ go to debugging;
+#endif
+ }
+#ifdef DEBUGGING
+ if (string_size < 0)
+ go to debugging;
+#endif
+
+ free (msg);
+
+ ret->h_aliases[alias_count] = NULL;
+ ret->h_addr_list[address_count] = NULL;
+
+ return ret;
+
+ corrupted:
+ free (msg);
+ /* Hopefully message corruption errors are temporary.
+ Should it be NO_RECOVERY ? */
+ h_errno = TRY_AGAIN;
+ return NULL;
+
+
+#ifdef DEBUGGING
+ debugging:
+ system_printf ("Please debug.");
+ free (msg);
+ free (ret);
+ h_errno = NO_RECOVERY;
+ return NULL;
+#endif
+}
+
+/* gethostbyname2: standards? */
+extern "C" struct hostent *
+gethostbyname2 (const char *name, int af)
+{
+ sig_dispatch_pending ();
+ myfault efault;
+ if (efault.faulted (EFAULT))
+ return NULL;
+
+ if (!(_res.options & RES_INIT))
+ res_init();
+ bool v4to6 = _res.options & RES_USE_INET6;
+
+ int type, addrsize_in, addrsize_out;
+ switch (af)
+ {
+ case AF_INET:
+ addrsize_in = NS_INADDRSZ;
+ addrsize_out = (v4to6) ? NS_IN6ADDRSZ : NS_INADDRSZ;
+ type = ns_t_a;
+ break;
+ case AF_INET6:
+ addrsize_in = addrsize_out = NS_IN6ADDRSZ;
+ type = ns_t_aaaa;
+ break;
+ default:
+ set_errno (EAFNOSUPPORT);
+ h_errno = NETDB_INTERNAL;
+ return NULL;
+ }
+
+ return gethostby_helper (name, af, type, addrsize_in, addrsize_out);
+}
+
/* exported as accept: standards? */
extern "C" int
cygwin_accept (int fd, struct sockaddr *peer, socklen_t *len)
@@ -2486,10 +2792,6 @@ cygwin_sendmsg (int fd, const struct msg
* SOFTWARE.
*/
-#define IN6ADDRSZ 16
-#define INADDRSZ 4
-#define INT16SZ 2
-
/* int
* inet_pton4(src, dst)
* like inet_aton() but without all the hexadecimal and shorthand.
Index: include/cygwin/version.h
===================================================================
RCS file: /cvs/src/src/winsup/cygwin/include/cygwin/version.h,v
retrieving revision 1.284
diff -u -p -r1.284 version.h
--- include/cygwin/version.h 19 Feb 2009 09:22:51 -0000 1.284
+++ include/cygwin/version.h 3 Mar 2009 11:54:12 -0000
@@ -349,12 +349,13 @@ details. */
198: Export reallocf.
199: Export open_wmemstream.
200: Export mbsnrtowcs, wcsnrtombs.
+ 201: Export gethostbyname2.
*/
/* Note that we forgot to bump the api for ualarm, strtoll, strtoull */
#define CYGWIN_VERSION_API_MAJOR 0
-#define CYGWIN_VERSION_API_MINOR 200
+#define CYGWIN_VERSION_API_MINOR 201
/* There is also a compatibity version number associated with the
shared memory regions. It is incremented when incompatible
Index: libc/minires.c
===================================================================
RCS file: /cvs/src/src/winsup/cygwin/libc/minires.c,v
retrieving revision 1.5
diff -u -p -r1.5 minires.c
--- libc/minires.c 3 Dec 2008 16:37:53 -0000 1.5
+++ libc/minires.c 3 Mar 2009 11:54:12 -0000
@@ -1,6 +1,6 @@
/* minires.c. Stub synchronous resolver for Cygwin.
- Copyright 2006, 2008 Red Hat, Inc.
+ Copyright 2006, 2008, 2009 Red Hat, Inc.
Written by Pierre A. Humblet <pierre.humb...@ieee.org>
@@ -99,6 +99,11 @@ static void get_options(res_state statp,
DPRINTF(statp->options & RES_DEBUG, "%s: 1\n", words[i]);
continue;
}
+ if (!strcasecmp("inet6", words[i])) {
+ statp->options |= RES_USE_INET6;
+ DPRINTF(statp->options & RES_DEBUG, "%s: 1\n", words[i]);
+ continue;
+ }
if (!strcasecmp("osquery", words[i])) {
statp->use_os = 1;
DPRINTF(statp->options & RES_DEBUG, "%s: 1\n", words[i]);
@@ -114,16 +119,22 @@ static void get_options(res_state statp,
continue;
}
*/
- if (!strcasecmp("retry", words[i])) {
+ if (!strcasecmp("retry", words[i])
+ || !strcasecmp("attempts", words[i])) {
if (value < 1)
value = 1;
+ else if (value > RES_MAXRETRY)
+ value = RES_MAXRETRY;
statp->retry = value;
DPRINTF(statp->options & RES_DEBUG, "%s: %d\n", words[i], value);
continue;
}
- if (!strcasecmp("retrans", words[i])) {
+ if (!strcasecmp("retrans", words[i])
+ || !strcasecmp("timeout", words[i])) {
if (value < 1)
value = 1;
+ else if (value > RES_MAXRETRANS)
+ value = RES_MAXRETRANS;
statp->retrans = value;
DPRINTF(statp->options & RES_DEBUG, "%s: %d\n", words[i], value);
continue;
@@ -270,6 +281,9 @@ int res_ninit(res_state statp)
int i;
statp->res_h_errno = NETDB_SUCCESS;
+ /* Only debug may be set before calling init */
+ statp->options &= RES_DEBUG;
+ statp->options |= RES_INIT | RES_DEFAULT;
statp->nscount = 0;
statp->os_query = NULL;
statp->retrans = RES_TIMEOUT; /* timeout in seconds */
@@ -299,9 +313,6 @@ int res_ninit(res_state statp)
statp->nsaddr_list[i].sin_port = htons(NAMESERVER_PORT);
bzero(statp->nsaddr_list[i].sin_zero,
sizeof(statp->nsaddr_list[i].sin_zero));
}
- /* Only debug may be set before calling init */
- statp->options &= RES_DEBUG;
- statp->options |= RES_INIT | RES_DEFAULT;
return 0;
}
@@ -806,7 +817,7 @@ int dn_expand(const unsigned char *msg,
exp_dn++;
else do {
if (len <= MAXLABEL) {
- if ((length -= (len + 1)) > 0 /* Need space for final . */
+ if ((length -= (len + 1)) >= 0 /* Need space for final . */
&& comp_dn + len <= eomorig) {
do { *exp_dn++ = *comp_dn++; } while (--len != 0);
*exp_dn++ = '.';
@@ -836,7 +847,6 @@ expand_fail:
return -1;
}
-
/*****************************************************************
*
dn_comp
@@ -926,8 +936,7 @@ int dn_comp(const char * exp_dn, u_char
}
/*****************************************************************
- *
- dn_skipname
+ * dn_skipname
Measures the compressed domain name length and returns it.
*****************************************************************/
@@ -949,3 +958,38 @@ int dn_skipname(const unsigned char *com
return comp_dn - comp_dn_orig;
}
+
+/*****************************************************************
+ * dn_length1 For internal use
+
+ Return length of uncompressesed name incl final 0.
+ *****************************************************************/
+
+int dn_length1(const unsigned char *msg, const unsigned char *eomorig,
+ const unsigned char *comp_dn)
+{
+ unsigned int len, length = 0;
+
+ errno = EINVAL;
+ if (comp_dn >= eomorig)
+ goto expand_fail;
+ else while ((len = *comp_dn++) != 0) {
+ if (len <= MAXLABEL) {
+ if ((comp_dn += len) <= eomorig)
+ length += len + 1;
+ else
+ goto expand_fail;
+ }
+ else if (len >= (128+64)) {
+ comp_dn = msg + (((len & ~(128+64)) << 8) + *comp_dn);
+ if (comp_dn >= eomorig)
+ goto expand_fail;
+ }
+ else
+ goto expand_fail;
+ }
+ return length;
+
+expand_fail:
+ return -1;
+}
--
Corinna Vinschen Please, send mails regarding Cygwin to
Cygwin Project Co-Leader cygwin AT cygwin DOT com
Red Hat
