diff options
Diffstat (limited to 'nscd/nscd_getai.c')
| -rw-r--r-- | nscd/nscd_getai.c | 83 |
1 files changed, 50 insertions, 33 deletions
diff --git a/nscd/nscd_getai.c b/nscd/nscd_getai.c index 24b374b0dc..5df32dc6dc 100644 --- a/nscd/nscd_getai.c +++ b/nscd/nscd_getai.c @@ -1,4 +1,4 @@ -/* Copyright (C) 2004 Free Software Foundation, Inc. +/* Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@redhat.com>, 2004. @@ -34,7 +34,7 @@ extern int __nss_not_use_nscd_hosts; /* We use the mapping from nscd_gethst. */ -libc_locked_map_ptr (extern, __hst_map_handle); +libc_locked_map_ptr (extern, __hst_map_handle) attribute_hidden; int @@ -42,6 +42,7 @@ __nscd_getai (const char *key, struct nscd_ai_result **result, int *h_errnop) { 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. */ @@ -50,49 +51,53 @@ __nscd_getai (const char *key, struct nscd_ai_result **result, int *h_errnop) &gc_cycle); retry:; - const ai_response_header *ai_resp = NULL; 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) { - const struct datahead *found = __nscd_cache_search (GETAI, key, keylen, - mapped); + struct datahead *found = __nscd_cache_search (GETAI, key, keylen, + mapped); if (found != NULL) { - ai_resp = &found->data[0].aidata; - respdata = (char *) (ai_resp + 1); + 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. */ - ai_response_header ai_resp_mem; - if (ai_resp == NULL) + if (respdata == NULL) { - sock = __nscd_open_socket (key, keylen, GETAI, &ai_resp_mem, - sizeof (ai_resp_mem)); + sock = __nscd_open_socket (key, keylen, GETAI, &ai_resp, + sizeof (ai_resp)); if (sock == -1) { - /* nscd not running or wrong version or hosts caching disabled. */ + /* nscd not running or wrong version. */ __nss_not_use_nscd_hosts = 1; goto out; } - - ai_resp = &ai_resp_mem; } - if (ai_resp->found == 1) + if (ai_resp.found == 1) { - size_t datalen = ai_resp->naddrs + ai_resp->addrslen + ai_resp->canonlen; + size_t datalen = ai_resp.naddrs + ai_resp.addrslen + ai_resp.canonlen; - /* This check is really only affects the case where the data + /* This check really only affects the case where the data comes from the mapped cache. */ - if ((char *) (ai_resp + 1) + datalen > recend) + if (respdata + datalen > recend) { assert (sock == -1); goto out; @@ -108,10 +113,10 @@ __nscd_getai (const char *key, struct nscd_ai_result **result, int *h_errnop) } /* Set up the data structure, including pointers. */ - resultbuf->naddrs = ai_resp->naddrs; + 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->family = (uint8_t *) (resultbuf->addrs + ai_resp.addrslen); + if (ai_resp.canonlen != 0) resultbuf->canon = (char *) (resultbuf->family + resultbuf->naddrs); else resultbuf->canon = NULL; @@ -119,8 +124,7 @@ __nscd_getai (const char *key, struct nscd_ai_result **result, int *h_errnop) if (respdata == NULL) { /* Read the data from the socket. */ - if ((size_t) TEMP_FAILURE_RETRY (__read (sock, resultbuf + 1, - datalen)) == datalen) + if ((size_t) __readall (sock, resultbuf + 1, datalen) == datalen) { retval = 0; *result = resultbuf; @@ -138,10 +142,13 @@ __nscd_getai (const char *key, struct nscd_ai_result **result, int *h_errnop) /* Try to detect corrupt databases. */ if (resultbuf->canon != NULL - && resultbuf->canon[ai_resp->canonlen - 1] != '\0') + && resultbuf->canon[ai_resp.canonlen - 1] != '\0') /* We cannot use the database. */ { - free (resultbuf); + if (mapped->head->gc_cycle != gc_cycle) + retval = -2; + else + free (resultbuf); goto out_close; } @@ -151,8 +158,15 @@ __nscd_getai (const char *key, struct nscd_ai_result **result, int *h_errnop) } 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; + *h_errnop = ai_resp.error; /* The `errno' to some value != ERANGE. */ __set_errno (ENOENT); @@ -164,22 +178,25 @@ __nscd_getai (const char *key, struct nscd_ai_result **result, int *h_errnop) if (sock != -1) close_not_cancel_no_status (sock); out: - if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0 && retval != -1) + 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) + if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1) { /* nscd is just running gc now. Disable using the mapping. */ - __nscd_unmap (mapped); + if (atomic_decrement_val (&mapped->counter) == 0) + __nscd_unmap (mapped); mapped = NO_MAPPING; } - *result = NULL; - free (resultbuf); - - goto retry; + if (retval != -1) + { + *result = NULL; + free (resultbuf); + goto retry; + } } return retval; |