diff options
Diffstat (limited to 'REORG.TODO/nscd/nscd_gethst_r.c')
| -rw-r--r-- | REORG.TODO/nscd/nscd_gethst_r.c | 459 |
1 files changed, 459 insertions, 0 deletions
diff --git a/REORG.TODO/nscd/nscd_gethst_r.c b/REORG.TODO/nscd/nscd_gethst_r.c new file mode 100644 index 0000000000..daa708b3d3 --- /dev/null +++ b/REORG.TODO/nscd/nscd_gethst_r.c @@ -0,0 +1,459 @@ +/* Copyright (C) 1998-2017 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, see + <http://www.gnu.org/licenses/>. */ + +#include <errno.h> +#include <resolv/resolv-internal.h> +#include <stdio.h> +#include <string.h> +#include <stdint.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_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); + } +} + + +uint32_t +__nscd_get_nl_timestamp (void) +{ + uint32_t retval; + if (__nss_not_use_nscd_hosts != 0) + return 0; + + /* __nscd_get_mapping can change hst_map_handle.mapped to NO_MAPPING. + However, __nscd_get_mapping assumes the prior value was not NO_MAPPING. + Thus we have to acquire the lock to prevent this thread from changing + hst_map_handle.mapped to NO_MAPPING while another thread is inside + __nscd_get_mapping. */ + if (!__nscd_acquire_maplock (&__hst_map_handle)) + return 0; + + struct mapped_database *map = __hst_map_handle.mapped; + + if (map == NULL + || (map != NO_MAPPING + && map->head->nscd_certainly_running == 0 + && map->head->timestamp + MAPPING_TIMEOUT < time (NULL))) + map = __nscd_get_mapping (GETFDHST, "hosts", &__hst_map_handle.mapped); + + if (map == NO_MAPPING) + retval = 0; + else + retval = map->head->extra_data[NSCD_HST_IDX_CONF_TIMESTAMP]; + + /* Release the lock. */ + __hst_map_handle.lock = 0; + + return retval; +} + + +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 (__glibc_unlikely (__nss_have_localdomain >= 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; + } + +#if !_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 (__glibc_unlikely (hst_resp.found == -1)) + { + /* 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 (__glibc_unlikely (cp > buffer + buflen)) + { + /* 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; +} |