| /* Copyright (C) 1998-2005, 2006, 2007, 2008, 2009 |
| Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998. |
| |
| 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 <errno.h> |
| #include <resolv.h> |
| #include <stdio.h> |
| #include <string.h> |
| #include <arpa/nameser.h> |
| #include <not-cancel.h> |
| |
| #include "nscd-client.h" |
| #include "nscd_proto.h" |
| |
| int __nss_not_use_nscd_hosts; |
| |
| static int nscd_gethst_r (const char *key, size_t keylen, request_type type, |
| struct hostent *resultbuf, char *buffer, |
| size_t buflen, struct hostent **result, |
| int *h_errnop) internal_function; |
| |
| |
| int |
| __nscd_gethostbyname_r (const char *name, struct hostent *resultbuf, |
| char *buffer, size_t buflen, struct hostent **result, |
| int *h_errnop) |
| { |
| request_type reqtype; |
| |
| reqtype = (_res.options & RES_USE_INET6) ? GETHOSTBYNAMEv6 : GETHOSTBYNAME; |
| |
| return nscd_gethst_r (name, strlen (name) + 1, reqtype, resultbuf, |
| buffer, buflen, result, h_errnop); |
| } |
| |
| |
| int |
| __nscd_gethostbyname2_r (const char *name, int af, struct hostent *resultbuf, |
| char *buffer, size_t buflen, struct hostent **result, |
| int *h_errnop) |
| { |
| request_type reqtype; |
| |
| reqtype = af == AF_INET6 ? GETHOSTBYNAMEv6 : GETHOSTBYNAME; |
| |
| return nscd_gethst_r (name, strlen (name) + 1, reqtype, resultbuf, |
| buffer, buflen, result, h_errnop); |
| } |
| |
| |
| int |
| __nscd_gethostbyaddr_r (const void *addr, socklen_t len, int type, |
| struct hostent *resultbuf, char *buffer, size_t buflen, |
| struct hostent **result, int *h_errnop) |
| { |
| request_type reqtype; |
| |
| if (!((len == INADDRSZ && type == AF_INET) |
| || (len == IN6ADDRSZ && type == AF_INET6))) |
| /* LEN and TYPE do not match. */ |
| return -1; |
| |
| reqtype = type == AF_INET6 ? GETHOSTBYADDRv6 : GETHOSTBYADDR; |
| |
| return nscd_gethst_r (addr, len, reqtype, resultbuf, buffer, buflen, result, |
| h_errnop); |
| } |
| |
| |
| libc_locked_map_ptr (, __hst_map_handle) attribute_hidden; |
| /* Note that we only free the structure if necessary. The memory |
| mapping is not removed since it is not visible to the malloc |
| handling. */ |
| libc_freeres_fn (hst_map_free) |
| { |
| if (__hst_map_handle.mapped != NO_MAPPING) |
| { |
| void *p = __hst_map_handle.mapped; |
| __hst_map_handle.mapped = NO_MAPPING; |
| free (p); |
| } |
| } |
| |
| |
| int __nss_have_localdomain attribute_hidden; |
| |
| static int |
| internal_function |
| nscd_gethst_r (const char *key, size_t keylen, request_type type, |
| struct hostent *resultbuf, char *buffer, size_t buflen, |
| struct hostent **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; |
| } |
| } |
| |
| 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:; |
| const char *h_name = NULL; |
| const uint32_t *aliases_len = NULL; |
| const char *addr_list = NULL; |
| size_t addr_list_len = 0; |
| int retval = -1; |
| const char *recend = (const char *) ~UINTMAX_C (0); |
| int sock = -1; |
| hst_response_header hst_resp; |
| if (mapped != NO_MAPPING) |
| { |
| /* No const qualifier, as it can change during garbage collection. */ |
| struct datahead *found = __nscd_cache_search (type, key, keylen, mapped, |
| sizeof hst_resp); |
| if (found != NULL) |
| { |
| h_name = (char *) (&found->data[0].hstdata + 1); |
| hst_resp = found->data[0].hstdata; |
| aliases_len = (uint32_t *) (h_name + hst_resp.h_name_len); |
| addr_list = ((char *) aliases_len |
| + hst_resp.h_aliases_cnt * sizeof (uint32_t)); |
| addr_list_len = hst_resp.h_addr_list_cnt * INADDRSZ; |
| recend = (const char *) found->data + found->recsize; |
| /* Now check if we can trust hst_resp fields. If GC is |
| in progress, it can contain anything. */ |
| if (mapped->head->gc_cycle != gc_cycle) |
| { |
| retval = -2; |
| goto out; |
| } |
| |
| #ifndef _STRING_ARCH_unaligned |
| /* The aliases_len array in the mapped database might very |
| well be unaligned. We will access it word-wise so on |
| platforms which do not tolerate unaligned accesses we |
| need to make an aligned copy. */ |
| if (((uintptr_t) aliases_len & (__alignof__ (*aliases_len) - 1)) |
| != 0) |
| { |
| uint32_t *tmp = alloca (hst_resp.h_aliases_cnt |
| * sizeof (uint32_t)); |
| aliases_len = memcpy (tmp, aliases_len, |
| hst_resp.h_aliases_cnt |
| * sizeof (uint32_t)); |
| } |
| #endif |
| if (type != GETHOSTBYADDR && type != GETHOSTBYNAME) |
| { |
| if (hst_resp.h_length == INADDRSZ) |
| addr_list += addr_list_len; |
| addr_list_len = hst_resp.h_addr_list_cnt * IN6ADDRSZ; |
| } |
| if (__builtin_expect ((const char *) addr_list + addr_list_len |
| > recend, 0)) |
| goto out; |
| } |
| } |
| |
| if (h_name == NULL) |
| { |
| sock = __nscd_open_socket (key, keylen, type, &hst_resp, |
| sizeof (hst_resp)); |
| if (sock == -1) |
| { |
| __nss_not_use_nscd_hosts = 1; |
| goto out; |
| } |
| } |
| |
| /* No value found so far. */ |
| *result = NULL; |
| |
| if (__builtin_expect (hst_resp.found == -1, 0)) |
| { |
| /* The daemon does not cache this database. */ |
| __nss_not_use_nscd_hosts = 1; |
| goto out_close; |
| } |
| |
| if (hst_resp.found == 1) |
| { |
| char *cp = buffer; |
| uintptr_t align1; |
| uintptr_t align2; |
| size_t total_len; |
| ssize_t cnt; |
| char *ignore; |
| int n; |
| |
| /* A first check whether the buffer is sufficiently large is possible. */ |
| /* Now allocate the buffer the array for the group members. We must |
| align the pointer and the base of the h_addr_list pointers. */ |
| align1 = ((__alignof__ (char *) - (cp - ((char *) 0))) |
| & (__alignof__ (char *) - 1)); |
| align2 = ((__alignof__ (char *) - ((cp + align1 + hst_resp.h_name_len) |
| - ((char *) 0))) |
| & (__alignof__ (char *) - 1)); |
| if (buflen < (align1 + hst_resp.h_name_len + align2 |
| + ((hst_resp.h_aliases_cnt + hst_resp.h_addr_list_cnt |
| + 2) |
| * sizeof (char *)) |
| + hst_resp.h_addr_list_cnt * (type == AF_INET |
| ? INADDRSZ : IN6ADDRSZ))) |
| { |
| no_room: |
| *h_errnop = NETDB_INTERNAL; |
| __set_errno (ERANGE); |
| retval = ERANGE; |
| goto out_close; |
| } |
| cp += align1; |
| |
| /* Prepare the result as far as we can. */ |
| resultbuf->h_aliases = (char **) cp; |
| cp += (hst_resp.h_aliases_cnt + 1) * sizeof (char *); |
| resultbuf->h_addr_list = (char **) cp; |
| cp += (hst_resp.h_addr_list_cnt + 1) * sizeof (char *); |
| |
| resultbuf->h_name = cp; |
| cp += hst_resp.h_name_len + align2; |
| |
| if (type == GETHOSTBYADDR || type == GETHOSTBYNAME) |
| { |
| resultbuf->h_addrtype = AF_INET; |
| resultbuf->h_length = INADDRSZ; |
| } |
| else |
| { |
| resultbuf->h_addrtype = AF_INET6; |
| resultbuf->h_length = IN6ADDRSZ; |
| } |
| for (cnt = 0; cnt < hst_resp.h_addr_list_cnt; ++cnt) |
| { |
| resultbuf->h_addr_list[cnt] = cp; |
| cp += resultbuf->h_length; |
| } |
| resultbuf->h_addr_list[cnt] = NULL; |
| |
| if (h_name == NULL) |
| { |
| struct iovec vec[4]; |
| |
| vec[0].iov_base = resultbuf->h_name; |
| vec[0].iov_len = hst_resp.h_name_len; |
| total_len = hst_resp.h_name_len; |
| n = 1; |
| |
| if (hst_resp.h_aliases_cnt > 0) |
| { |
| aliases_len = alloca (hst_resp.h_aliases_cnt |
| * sizeof (uint32_t)); |
| vec[n].iov_base = (void *) aliases_len; |
| vec[n].iov_len = hst_resp.h_aliases_cnt * sizeof (uint32_t); |
| |
| total_len += hst_resp.h_aliases_cnt * sizeof (uint32_t); |
| ++n; |
| } |
| |
| if (type == GETHOSTBYADDR || type == GETHOSTBYNAME) |
| { |
| vec[n].iov_base = resultbuf->h_addr_list[0]; |
| vec[n].iov_len = hst_resp.h_addr_list_cnt * INADDRSZ; |
| |
| total_len += hst_resp.h_addr_list_cnt * INADDRSZ; |
| |
| ++n; |
| } |
| else |
| { |
| if (hst_resp.h_length == INADDRSZ) |
| { |
| ignore = alloca (hst_resp.h_addr_list_cnt * INADDRSZ); |
| vec[n].iov_base = ignore; |
| vec[n].iov_len = hst_resp.h_addr_list_cnt * INADDRSZ; |
| |
| total_len += hst_resp.h_addr_list_cnt * INADDRSZ; |
| |
| ++n; |
| } |
| |
| vec[n].iov_base = resultbuf->h_addr_list[0]; |
| vec[n].iov_len = hst_resp.h_addr_list_cnt * IN6ADDRSZ; |
| |
| total_len += hst_resp.h_addr_list_cnt * IN6ADDRSZ; |
| |
| ++n; |
| } |
| |
| if ((size_t) __readvall (sock, vec, n) != total_len) |
| goto out_close; |
| } |
| else |
| { |
| memcpy (resultbuf->h_name, h_name, hst_resp.h_name_len); |
| memcpy (resultbuf->h_addr_list[0], addr_list, addr_list_len); |
| } |
| |
| /* Now we also can read the aliases. */ |
| total_len = 0; |
| for (cnt = 0; cnt < hst_resp.h_aliases_cnt; ++cnt) |
| { |
| resultbuf->h_aliases[cnt] = cp; |
| cp += aliases_len[cnt]; |
| total_len += aliases_len[cnt]; |
| } |
| resultbuf->h_aliases[cnt] = NULL; |
| |
| if (__builtin_expect ((const char *) addr_list + addr_list_len |
| + total_len > recend, 0)) |
| { |
| /* aliases_len array might contain garbage during nscd GC cycle, |
| retry rather than fail in that case. */ |
| if (addr_list != NULL && mapped->head->gc_cycle != gc_cycle) |
| retval = -2; |
| goto out_close; |
| } |
| /* See whether this would exceed the buffer capacity. */ |
| if (__builtin_expect (cp > buffer + buflen, 0)) |
| { |
| /* aliases_len array might contain garbage during nscd GC cycle, |
| retry rather than fail in that case. */ |
| if (addr_list != NULL && mapped->head->gc_cycle != gc_cycle) |
| { |
| retval = -2; |
| goto out_close; |
| } |
| goto no_room; |
| } |
| |
| /* And finally read the aliases. */ |
| if (addr_list == NULL) |
| { |
| if (total_len == 0 |
| || ((size_t) __readall (sock, resultbuf->h_aliases[0], total_len) |
| == total_len)) |
| { |
| retval = 0; |
| *result = resultbuf; |
| } |
| } |
| else |
| { |
| memcpy (resultbuf->h_aliases[0], |
| (const char *) addr_list + addr_list_len, total_len); |
| |
| /* Try to detect corrupt databases. */ |
| if (resultbuf->h_name[hst_resp.h_name_len - 1] != '\0' |
| || ({for (cnt = 0; cnt < hst_resp.h_aliases_cnt; ++cnt) |
| if (resultbuf->h_aliases[cnt][aliases_len[cnt] - 1] |
| != '\0') |
| break; |
| cnt < hst_resp.h_aliases_cnt; })) |
| { |
| /* We cannot use the database. */ |
| if (mapped->head->gc_cycle != gc_cycle) |
| retval = -2; |
| goto out_close; |
| } |
| |
| retval = 0; |
| *result = resultbuf; |
| } |
| } |
| else |
| { |
| /* Store the error number. */ |
| *h_errnop = hst_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) |
| goto retry; |
| } |
| |
| return retval; |
| } |