| /* Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 |
| Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Ulrich Drepper <drepper@redhat.com>, 2004. |
| |
| 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 <assert.h> |
| #include <errno.h> |
| #include <netdb.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <unistd.h> |
| #include <not-cancel.h> |
| |
| #include "nscd-client.h" |
| #include "nscd_proto.h" |
| |
| |
| /* Define in nscd_gethst_r.c. */ |
| extern int __nss_not_use_nscd_hosts; |
| |
| |
| /* We use the mapping from nscd_gethst. */ |
| libc_locked_map_ptr (extern, __hst_map_handle) attribute_hidden; |
| |
| /* Defined in nscd_gethst_r.c. */ |
| extern int __nss_have_localdomain attribute_hidden; |
| |
| |
| int |
| __nscd_getai (const char *key, struct nscd_ai_result **result, int *h_errnop) |
| { |
| if (__builtin_expect (__nss_have_localdomain >= 0, 0)) |
| { |
| if (__nss_have_localdomain == 0) |
| __nss_have_localdomain = getenv ("LOCALDOMAIN") != NULL ? 1 : -1; |
| if (__nss_have_localdomain > 0) |
| { |
| __nss_not_use_nscd_hosts = 1; |
| return -1; |
| } |
| } |
| |
| size_t keylen = strlen (key) + 1; |
| int gc_cycle; |
| int nretries = 0; |
| |
| /* If the mapping is available, try to search there instead of |
| communicating with the nscd. */ |
| struct mapped_database *mapped; |
| mapped = __nscd_get_map_ref (GETFDHST, "hosts", &__hst_map_handle, |
| &gc_cycle); |
| |
| retry:; |
| struct nscd_ai_result *resultbuf = NULL; |
| const char *recend = (const char *) ~UINTMAX_C (0); |
| char *respdata = NULL; |
| int retval = -1; |
| int sock = -1; |
| ai_response_header ai_resp; |
| |
| if (mapped != NO_MAPPING) |
| { |
| struct datahead *found = __nscd_cache_search (GETAI, key, keylen, |
| mapped, sizeof ai_resp); |
| if (found != NULL) |
| { |
| respdata = (char *) (&found->data[0].aidata + 1); |
| ai_resp = found->data[0].aidata; |
| recend = (const char *) found->data + found->recsize; |
| /* Now check if we can trust ai_resp fields. If GC is |
| in progress, it can contain anything. */ |
| if (mapped->head->gc_cycle != gc_cycle) |
| { |
| retval = -2; |
| goto out; |
| } |
| } |
| } |
| |
| /* If we do not have the cache mapped, try to get the data over the |
| socket. */ |
| if (respdata == NULL) |
| { |
| sock = __nscd_open_socket (key, keylen, GETAI, &ai_resp, |
| sizeof (ai_resp)); |
| if (sock == -1) |
| { |
| /* nscd not running or wrong version. */ |
| __nss_not_use_nscd_hosts = 1; |
| goto out; |
| } |
| } |
| |
| if (ai_resp.found == 1) |
| { |
| size_t datalen = ai_resp.naddrs + ai_resp.addrslen + ai_resp.canonlen; |
| |
| /* This check really only affects the case where the data |
| comes from the mapped cache. */ |
| if (respdata + datalen > recend) |
| { |
| assert (sock == -1); |
| goto out; |
| } |
| |
| /* Create result. */ |
| resultbuf = (struct nscd_ai_result *) malloc (sizeof (*resultbuf) |
| + datalen); |
| if (resultbuf == NULL) |
| { |
| *h_errnop = NETDB_INTERNAL; |
| goto out_close; |
| } |
| |
| /* Set up the data structure, including pointers. */ |
| resultbuf->naddrs = ai_resp.naddrs; |
| resultbuf->addrs = (char *) (resultbuf + 1); |
| resultbuf->family = (uint8_t *) (resultbuf->addrs + ai_resp.addrslen); |
| if (ai_resp.canonlen != 0) |
| resultbuf->canon = (char *) (resultbuf->family + resultbuf->naddrs); |
| else |
| resultbuf->canon = NULL; |
| |
| if (respdata == NULL) |
| { |
| /* Read the data from the socket. */ |
| if ((size_t) __readall (sock, resultbuf + 1, datalen) == datalen) |
| { |
| retval = 0; |
| *result = resultbuf; |
| } |
| else |
| { |
| free (resultbuf); |
| *h_errnop = NETDB_INTERNAL; |
| } |
| } |
| else |
| { |
| /* Copy the data in the block. */ |
| memcpy (resultbuf + 1, respdata, datalen); |
| |
| /* Try to detect corrupt databases. */ |
| if (resultbuf->canon != NULL |
| && resultbuf->canon[ai_resp.canonlen - 1] != '\0') |
| /* We cannot use the database. */ |
| { |
| if (mapped->head->gc_cycle != gc_cycle) |
| retval = -2; |
| else |
| free (resultbuf); |
| goto out_close; |
| } |
| |
| retval = 0; |
| *result = resultbuf; |
| } |
| } |
| else |
| { |
| if (__builtin_expect (ai_resp.found == -1, 0)) |
| { |
| /* The daemon does not cache this database. */ |
| __nss_not_use_nscd_hosts = 1; |
| goto out_close; |
| } |
| |
| /* Store the error number. */ |
| *h_errnop = ai_resp.error; |
| |
| /* Set errno to 0 to indicate no error, just no found record. */ |
| __set_errno (0); |
| /* Even though we have not found anything, the result is zero. */ |
| retval = 0; |
| } |
| |
| out_close: |
| if (sock != -1) |
| close_not_cancel_no_status (sock); |
| out: |
| if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0) |
| { |
| /* When we come here this means there has been a GC cycle while we |
| were looking for the data. This means the data might have been |
| inconsistent. Retry if possible. */ |
| if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1) |
| { |
| /* nscd is just running gc now. Disable using the mapping. */ |
| if (atomic_decrement_val (&mapped->counter) == 0) |
| __nscd_unmap (mapped); |
| mapped = NO_MAPPING; |
| } |
| |
| if (retval != -1) |
| { |
| *result = NULL; |
| free (resultbuf); |
| goto retry; |
| } |
| } |
| |
| return retval; |
| } |