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Diffstat (limited to 'nscd/nscd_getai.c')
-rw-r--r--nscd/nscd_getai.c71
1 files changed, 41 insertions, 30 deletions
diff --git a/nscd/nscd_getai.c b/nscd/nscd_getai.c
index b59c31e..5df32dc 100644
--- a/nscd/nscd_getai.c
+++ b/nscd/nscd_getai.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2004, 2005, 2006 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.
@@ -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. */
__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;
@@ -137,10 +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;
}
@@ -150,7 +158,7 @@ __nscd_getai (const char *key, struct nscd_ai_result **result, int *h_errnop)
}
else
{
- if (__builtin_expect (ai_resp->found == -1, 0))
+ if (__builtin_expect (ai_resp.found == -1, 0))
{
/* The daemon does not cache this database. */
__nss_not_use_nscd_hosts = 1;
@@ -158,7 +166,7 @@ __nscd_getai (const char *key, struct nscd_ai_result **result, int *h_errnop)
}
/* Store the error number. */
- *h_errnop = ai_resp->error;
+ *h_errnop = ai_resp.error;
/* The `errno' to some value != ERANGE. */
__set_errno (ENOENT);
@@ -170,22 +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;