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[PATCH v2][BZ #16077] Get canonical name in getaddrinfo from hosts file for AF_INET
- From: Siddhesh Poyarekar <siddhesh at redhat dot com>
- To: Andreas Schwab <schwab at suse dot de>
- Cc: libc-alpha at sourceware dot org
- Date: Mon, 25 Nov 2013 20:46:49 +0530
- Subject: [PATCH v2][BZ #16077] Get canonical name in getaddrinfo from hosts file for AF_INET
- Authentication-results: sourceware.org; auth=none
- References: <20131023100431 dot GG7401 at spoyarek dot pnq dot redhat dot com> <mvmwqjwen32 dot fsf at hawking dot suse dot de>
On Mon, Nov 25, 2013 at 12:29:37PM +0100, Andreas Schwab wrote:
> gethostbyname2 should be implemented on top of gethostbyname3, not the
> other way round.
OK, here's a new version then - I was trying to avoid a large change,
but I realized I defeated my own purpose of trying to keep things
consistent.
I have junked the HOSTS_DB_LOOKUP macro and replaced if with
_nss_files_gethostbyname3_r (reusing most of the macro code) and then
call it from _nss_files_gethostbyname_r and
_nss_files_gethostbyname2_r. Verified that nothing breaks due to this
by building a Fedora package with the patch and testing it for lookups
from /etc/hosts on my test box. OK to commit?
Siddhesh
[BZ #16077]
* nss/Versions (libnss_files): Add
_nss_files_gethostbyname3_r.
* nss/nss_files/files-hosts.c (_nss_files_gethostbyname3_r):
New function.
(HOST_DB_LOOKUP): Remove macro.
(_nss_files_gethostbyname_r): Implement function without the
HOST_DB_LOOKUP macro.
(_nss_files_gethostbyname2_r): Likewise.
diff --git a/nss/Versions b/nss/Versions
index d13d570..f8ababc 100644
--- a/nss/Versions
+++ b/nss/Versions
@@ -40,6 +40,7 @@ libnss_files {
_nss_files_endhostent;
_nss_files_gethostbyaddr_r;
_nss_files_gethostbyname2_r;
+ _nss_files_gethostbyname3_r;
_nss_files_gethostbyname4_r;
_nss_files_gethostbyname_r;
_nss_files_gethostent_r;
diff --git a/nss/nss_files/files-hosts.c b/nss/nss_files/files-hosts.c
index b1b71ec..9605ee6 100644
--- a/nss/nss_files/files-hosts.c
+++ b/nss/nss_files/files-hosts.c
@@ -97,262 +97,12 @@ LINE_PARSER
STRING_FIELD (result->h_name, isspace, 1);
})
-
-
-#define HOST_DB_LOOKUP(name, keysize, keypattern, break_if_match, proto...) \
-enum nss_status \
-_nss_files_get##name##_r (proto, \
- struct STRUCTURE *result, char *buffer, \
- size_t buflen, int *errnop H_ERRNO_PROTO) \
-{ \
- uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct hostent_data); \
- buffer += pad; \
- buflen = buflen > pad ? buflen - pad : 0; \
- \
- __libc_lock_lock (lock); \
- \
- /* Reset file pointer to beginning or open file. */ \
- enum nss_status status = internal_setent (keep_stream); \
- \
- if (status == NSS_STATUS_SUCCESS) \
- { \
- /* Tell getent function that we have repositioned the file pointer. */ \
- last_use = getby; \
- \
- while ((status = internal_getent (result, buffer, buflen, errnop \
- H_ERRNO_ARG EXTRA_ARGS_VALUE)) \
- == NSS_STATUS_SUCCESS) \
- { break_if_match } \
- \
- if (status == NSS_STATUS_SUCCESS \
- && _res_hconf.flags & HCONF_FLAG_MULTI) \
- { \
- /* We have to get all host entries from the file. */ \
- size_t tmp_buflen = MIN (buflen, 4096); \
- char tmp_buffer_stack[tmp_buflen] \
- __attribute__ ((__aligned__ (__alignof__ (struct hostent_data))));\
- char *tmp_buffer = tmp_buffer_stack; \
- struct hostent tmp_result_buf; \
- int naddrs = 1; \
- int naliases = 0; \
- char *bufferend; \
- bool tmp_buffer_malloced = false; \
- \
- while (result->h_aliases[naliases] != NULL) \
- ++naliases; \
- \
- bufferend = (char *) &result->h_aliases[naliases + 1]; \
- \
- again: \
- while ((status = internal_getent (&tmp_result_buf, tmp_buffer, \
- tmp_buflen, errnop H_ERRNO_ARG \
- EXTRA_ARGS_VALUE)) \
- == NSS_STATUS_SUCCESS) \
- { \
- int matches = 1; \
- struct hostent *old_result = result; \
- result = &tmp_result_buf; \
- /* The following piece is a bit clumsy but we want to use the \
- `break_if_match' value. The optimizer should do its \
- job. */ \
- do \
- { \
- break_if_match \
- result = old_result; \
- } \
- while ((matches = 0)); \
- \
- if (matches) \
- { \
- /* We could be very clever and try to recycle a few bytes \
- in the buffer instead of generating new arrays. But \
- we are not doing this here since it's more work than \
- it's worth. Simply let the user provide a bit bigger \
- buffer. */ \
- char **new_h_addr_list; \
- char **new_h_aliases; \
- int newaliases = 0; \
- size_t newstrlen = 0; \
- int cnt; \
- \
- /* Count the new aliases and the length of the strings. */ \
- while (tmp_result_buf.h_aliases[newaliases] != NULL) \
- { \
- char *cp = tmp_result_buf.h_aliases[newaliases]; \
- ++newaliases; \
- newstrlen += strlen (cp) + 1; \
- } \
- /* If the real name is different add it also to the \
- aliases. This means that there is a duplication \
- in the alias list but this is really the user's \
- problem. */ \
- if (strcmp (old_result->h_name, \
- tmp_result_buf.h_name) != 0) \
- { \
- ++newaliases; \
- newstrlen += strlen (tmp_result_buf.h_name) + 1; \
- } \
- \
- /* Make sure bufferend is aligned. */ \
- assert ((bufferend - (char *) 0) % sizeof (char *) == 0); \
- \
- /* Now we can check whether the buffer is large enough. \
- 16 is the maximal size of the IP address. */ \
- if (bufferend + 16 + (naddrs + 2) * sizeof (char *) \
- + roundup (newstrlen, sizeof (char *)) \
- + (naliases + newaliases + 1) * sizeof (char *) \
- >= buffer + buflen) \
- { \
- *errnop = ERANGE; \
- *herrnop = NETDB_INTERNAL; \
- status = NSS_STATUS_TRYAGAIN; \
- goto out; \
- } \
- \
- new_h_addr_list = \
- (char **) (bufferend \
- + roundup (newstrlen, sizeof (char *)) \
- + 16); \
- new_h_aliases = \
- (char **) ((char *) new_h_addr_list \
- + (naddrs + 2) * sizeof (char *)); \
- \
- /* Copy the old data in the new arrays. */ \
- for (cnt = 0; cnt < naddrs; ++cnt) \
- new_h_addr_list[cnt] = old_result->h_addr_list[cnt]; \
- \
- for (cnt = 0; cnt < naliases; ++cnt) \
- new_h_aliases[cnt] = old_result->h_aliases[cnt]; \
- \
- /* Store the new strings. */ \
- cnt = 0; \
- while (tmp_result_buf.h_aliases[cnt] != NULL) \
- { \
- new_h_aliases[naliases++] = bufferend; \
- bufferend = (__stpcpy (bufferend, \
- tmp_result_buf.h_aliases[cnt]) \
- + 1); \
- ++cnt; \
- } \
- \
- if (cnt < newaliases) \
- { \
- new_h_aliases[naliases++] = bufferend; \
- bufferend = __stpcpy (bufferend, \
- tmp_result_buf.h_name) + 1; \
- } \
- \
- /* Final NULL pointer. */ \
- new_h_aliases[naliases] = NULL; \
- \
- /* Round up the buffer end address. */ \
- bufferend += (sizeof (char *) \
- - ((bufferend - (char *) 0) \
- % sizeof (char *))) % sizeof (char *); \
- \
- /* Now the new address. */ \
- new_h_addr_list[naddrs++] = \
- memcpy (bufferend, tmp_result_buf.h_addr, \
- tmp_result_buf.h_length); \
- \
- /* Also here a final NULL pointer. */ \
- new_h_addr_list[naddrs] = NULL; \
- \
- /* Store the new array pointers. */ \
- old_result->h_aliases = new_h_aliases; \
- old_result->h_addr_list = new_h_addr_list; \
- \
- /* Compute the new buffer end. */ \
- bufferend = (char *) &new_h_aliases[naliases + 1]; \
- assert (bufferend <= buffer + buflen); \
- \
- result = old_result; \
- } \
- } \
- \
- if (status == NSS_STATUS_TRYAGAIN) \
- { \
- size_t newsize = 2 * tmp_buflen; \
- if (tmp_buffer_malloced) \
- { \
- char *newp = realloc (tmp_buffer, newsize); \
- if (newp != NULL) \
- { \
- assert ((((uintptr_t) newp) \
- & (__alignof__ (struct hostent_data) - 1)) \
- == 0); \
- tmp_buffer = newp; \
- tmp_buflen = newsize; \
- goto again; \
- } \
- } \
- else if (!__libc_use_alloca (buflen + newsize)) \
- { \
- tmp_buffer = malloc (newsize); \
- if (tmp_buffer != NULL) \
- { \
- assert ((((uintptr_t) tmp_buffer) \
- & (__alignof__ (struct hostent_data) - 1)) \
- == 0); \
- tmp_buffer_malloced = true; \
- tmp_buflen = newsize; \
- goto again; \
- } \
- } \
- else \
- { \
- tmp_buffer \
- = extend_alloca (tmp_buffer, tmp_buflen, \
- newsize \
- + __alignof__ (struct hostent_data)); \
- tmp_buffer = (char *) (((uintptr_t) tmp_buffer \
- + __alignof__ (struct hostent_data) \
- - 1) \
- & ~(__alignof__ (struct hostent_data)\
- - 1)); \
- goto again; \
- } \
- } \
- else \
- status = NSS_STATUS_SUCCESS; \
- out: \
- if (tmp_buffer_malloced) \
- free (tmp_buffer); \
- } \
- \
- \
- if (! keep_stream) \
- internal_endent (); \
- } \
- \
- __libc_lock_unlock (lock); \
- \
- return status; \
-}
-
-
#define EXTRA_ARGS_VALUE \
, ((_res.options & RES_USE_INET6) ? AF_INET6 : AF_INET), \
((_res.options & RES_USE_INET6) ? AI_V4MAPPED : 0)
#include "files-XXX.c"
-HOST_DB_LOOKUP (hostbyname, ,,
- {
- LOOKUP_NAME_CASE (h_name, h_aliases)
- }, const char *name)
#undef EXTRA_ARGS_VALUE
-
-/* XXX Is using _res to determine whether we want to convert IPv4 addresses
- to IPv6 addresses really the right thing to do? */
-#define EXTRA_ARGS_VALUE \
- , af, ((_res.options & RES_USE_INET6) ? AI_V4MAPPED : 0)
-HOST_DB_LOOKUP (hostbyname2, ,,
- {
- LOOKUP_NAME_CASE (h_name, h_aliases)
- }, const char *name, int af)
-#undef EXTRA_ARGS_VALUE
-
-
/* We only need to consider IPv4 mapped addresses if the input to the
gethostbyaddr() function is an IPv6 address. */
#define EXTRA_ARGS_VALUE \
@@ -365,6 +115,263 @@ DB_LOOKUP (hostbyaddr, ,,,
}, const void *addr, socklen_t len, int af)
#undef EXTRA_ARGS_VALUE
+enum nss_status
+_nss_files_gethostbyname3_r (const char *name, int af, struct hostent *result,
+ char *buffer, size_t buflen, int *errnop,
+ int *herrnop, int32_t *ttlp, char **canonp)
+{
+ uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct hostent_data);
+ buffer += pad;
+ buflen = buflen > pad ? buflen - pad : 0;
+
+ __libc_lock_lock (lock);
+
+ /* Reset file pointer to beginning or open file. */
+ enum nss_status status = internal_setent (keep_stream);
+
+ if (status == NSS_STATUS_SUCCESS)
+ {
+ /* XXX Is using _res to determine whether we want to convert IPv4
+ addresses to IPv6 addresses really the right thing to do? */
+ int flags = ((_res.options & RES_USE_INET6) ? AI_V4MAPPED : 0);
+
+ /* Tell getent function that we have repositioned the file pointer. */
+ last_use = getby;
+
+ while ((status = internal_getent (result, buffer, buflen, errnop,
+ herrnop, af, flags))
+ == NSS_STATUS_SUCCESS)
+ {
+ LOOKUP_NAME_CASE (h_name, h_aliases)
+ }
+
+ if (status == NSS_STATUS_SUCCESS
+ && _res_hconf.flags & HCONF_FLAG_MULTI)
+ {
+ /* We have to get all host entries from the file. */
+ size_t tmp_buflen = MIN (buflen, 4096);
+ char tmp_buffer_stack[tmp_buflen]
+ __attribute__ ((__aligned__ (__alignof__ (struct hostent_data))));
+ char *tmp_buffer = tmp_buffer_stack;
+ struct hostent tmp_result_buf;
+ int naddrs = 1;
+ int naliases = 0;
+ char *bufferend;
+ bool tmp_buffer_malloced = false;
+
+ while (result->h_aliases[naliases] != NULL)
+ ++naliases;
+
+ bufferend = (char *) &result->h_aliases[naliases + 1];
+
+ again:
+ while ((status = internal_getent (&tmp_result_buf, tmp_buffer,
+ tmp_buflen, errnop, herrnop, af,
+ flags))
+ == NSS_STATUS_SUCCESS)
+ {
+ int matches = 1;
+ struct hostent *old_result = result;
+ result = &tmp_result_buf;
+ /* The following piece is a bit clumsy but we want to use the
+ `break_if_match' value. The optimizer should do its
+ job. */
+ do
+ {
+ LOOKUP_NAME_CASE (h_name, h_aliases)
+ result = old_result;
+ }
+ while ((matches = 0));
+
+ if (matches)
+ {
+ /* We could be very clever and try to recycle a few bytes
+ in the buffer instead of generating new arrays. But
+ we are not doing this here since it's more work than
+ it's worth. Simply let the user provide a bit bigger
+ buffer. */
+ char **new_h_addr_list;
+ char **new_h_aliases;
+ int newaliases = 0;
+ size_t newstrlen = 0;
+ int cnt;
+
+ /* Count the new aliases and the length of the strings. */
+ while (tmp_result_buf.h_aliases[newaliases] != NULL)
+ {
+ char *cp = tmp_result_buf.h_aliases[newaliases];
+ ++newaliases;
+ newstrlen += strlen (cp) + 1;
+ }
+ /* If the real name is different add it also to the
+ aliases. This means that there is a duplication
+ in the alias list but this is really the user's
+ problem. */
+ if (strcmp (old_result->h_name,
+ tmp_result_buf.h_name) != 0)
+ {
+ ++newaliases;
+ newstrlen += strlen (tmp_result_buf.h_name) + 1;
+ }
+
+ /* Make sure bufferend is aligned. */
+ assert ((bufferend - (char *) 0) % sizeof (char *) == 0);
+
+ /* Now we can check whether the buffer is large enough.
+ 16 is the maximal size of the IP address. */
+ if (bufferend + 16 + (naddrs + 2) * sizeof (char *)
+ + roundup (newstrlen, sizeof (char *))
+ + (naliases + newaliases + 1) * sizeof (char *)
+ >= buffer + buflen)
+ {
+ *errnop = ERANGE;
+ *herrnop = NETDB_INTERNAL;
+ status = NSS_STATUS_TRYAGAIN;
+ goto out;
+ }
+
+ new_h_addr_list =
+ (char **) (bufferend
+ + roundup (newstrlen, sizeof (char *))
+ + 16);
+ new_h_aliases =
+ (char **) ((char *) new_h_addr_list
+ + (naddrs + 2) * sizeof (char *));
+
+ /* Copy the old data in the new arrays. */
+ for (cnt = 0; cnt < naddrs; ++cnt)
+ new_h_addr_list[cnt] = old_result->h_addr_list[cnt];
+
+ for (cnt = 0; cnt < naliases; ++cnt)
+ new_h_aliases[cnt] = old_result->h_aliases[cnt];
+
+ /* Store the new strings. */
+ cnt = 0;
+ while (tmp_result_buf.h_aliases[cnt] != NULL)
+ {
+ new_h_aliases[naliases++] = bufferend;
+ bufferend = (__stpcpy (bufferend,
+ tmp_result_buf.h_aliases[cnt])
+ + 1);
+ ++cnt;
+ }
+
+ if (cnt < newaliases)
+ {
+ new_h_aliases[naliases++] = bufferend;
+ bufferend = __stpcpy (bufferend,
+ tmp_result_buf.h_name) + 1;
+ }
+
+ /* Final NULL pointer. */
+ new_h_aliases[naliases] = NULL;
+
+ /* Round up the buffer end address. */
+ bufferend += (sizeof (char *)
+ - ((bufferend - (char *) 0)
+ % sizeof (char *))) % sizeof (char *);
+
+ /* Now the new address. */
+ new_h_addr_list[naddrs++] =
+ memcpy (bufferend, tmp_result_buf.h_addr,
+ tmp_result_buf.h_length);
+
+ /* Also here a final NULL pointer. */
+ new_h_addr_list[naddrs] = NULL;
+
+ /* Store the new array pointers. */
+ old_result->h_aliases = new_h_aliases;
+ old_result->h_addr_list = new_h_addr_list;
+
+ /* Compute the new buffer end. */
+ bufferend = (char *) &new_h_aliases[naliases + 1];
+ assert (bufferend <= buffer + buflen);
+
+ result = old_result;
+ }
+ }
+
+ if (status == NSS_STATUS_TRYAGAIN)
+ {
+ size_t newsize = 2 * tmp_buflen;
+ if (tmp_buffer_malloced)
+ {
+ char *newp = realloc (tmp_buffer, newsize);
+ if (newp != NULL)
+ {
+ assert ((((uintptr_t) newp)
+ & (__alignof__ (struct hostent_data) - 1))
+ == 0);
+ tmp_buffer = newp;
+ tmp_buflen = newsize;
+ goto again;
+ }
+ }
+ else if (!__libc_use_alloca (buflen + newsize))
+ {
+ tmp_buffer = malloc (newsize);
+ if (tmp_buffer != NULL)
+ {
+ assert ((((uintptr_t) tmp_buffer)
+ & (__alignof__ (struct hostent_data) - 1))
+ == 0);
+ tmp_buffer_malloced = true;
+ tmp_buflen = newsize;
+ goto again;
+ }
+ }
+ else
+ {
+ tmp_buffer
+ = extend_alloca (tmp_buffer, tmp_buflen,
+ newsize
+ + __alignof__ (struct hostent_data));
+ tmp_buffer = (char *) (((uintptr_t) tmp_buffer
+ + __alignof__ (struct hostent_data)
+ - 1)
+ & ~(__alignof__ (struct hostent_data)
+ - 1));
+ goto again;
+ }
+ }
+ else
+ status = NSS_STATUS_SUCCESS;
+ out:
+ if (tmp_buffer_malloced)
+ free (tmp_buffer);
+ }
+
+ if (! keep_stream)
+ internal_endent ();
+ }
+
+ if (result && canonp && status == NSS_STATUS_SUCCESS)
+ *canonp = result->h_name;
+
+ __libc_lock_unlock (lock);
+
+ return status;
+}
+
+enum nss_status
+_nss_files_gethostbyname_r (const char *name, struct hostent *result,
+ char *buffer, size_t buflen, int *errnop,
+ int *herrnop)
+{
+ int af = ((_res.options & RES_USE_INET6) ? AF_INET6 : AF_INET);
+
+ return _nss_files_gethostbyname3_r (name, af, result, buffer, buflen,
+ errnop, herrnop, NULL, NULL);
+}
+
+enum nss_status
+_nss_files_gethostbyname2_r (const char *name, int af, struct hostent *result,
+ char *buffer, size_t buflen, int *errnop,
+ int *herrnop)
+{
+ return _nss_files_gethostbyname3_r (name, af, result, buffer, buflen,
+ errnop, herrnop, NULL, NULL);
+}
enum nss_status
_nss_files_gethostbyname4_r (const char *name, struct gaih_addrtuple **pat,