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Further robustify nscd database lookup.

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We can compute an absolute maximum for the number of elements which
can fit into the currently mapped database.  Stop after that many
iterations.
This commit is contained in:
Ulrich Drepper 2009-05-15 21:33:43 -07:00
parent cfe1fc1013
commit 831a40494d
4 changed files with 17 additions and 7 deletions
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9
ChangeLog
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@ -1,3 +1,12 @@
2009-05-15 Ulrich Drepper <drepper@redhat.com>
* nscd/nscd.h: Move Definition for BLOCK_ALIGN_LOG, BLOCK_ALIGN, and
BLOCK_ALIGN_M1 to ...
* nscd/nscd-client.h: ...here.
* nscd/nscd_helper.c (__nscd_cache_search): Introduce loop counter.
Use it if we absolutely cannot reach any more correct list elements
because that many do not fit into the currently mapped database.
2009-05-14 Jakub Jelinek <jakub@redhat.com>
* nscd/nscd_helper.c: Include stddef.h.

7
nscd/nscd-client.h
View file

@ -44,9 +44,14 @@
/* Path for the configuration file. */
#define _PATH_NSCDCONF "/etc/nscd.conf"
/* Maximu allowed length for the key. */
/* Maximum allowed length for the key. */
#define MAXKEYLEN 1024
/* Maximum alignment requirement we will encounter. */
#define BLOCK_ALIGN_LOG 3
#define BLOCK_ALIGN (1 << BLOCK_ALIGN_LOG)
#define BLOCK_ALIGN_M1 (BLOCK_ALIGN - 1)
/* Available services. */
typedef enum

5
nscd/nscd.h
View file

@ -111,11 +111,6 @@ struct database_dyn
/* Path used when not using persistent storage. */
#define _PATH_NSCD_XYZ_DB_TMP "/var/run/nscd/dbXXXXXX"
/* Maximum alignment requirement we will encounter. */
#define BLOCK_ALIGN_LOG 3
#define BLOCK_ALIGN (1 << BLOCK_ALIGN_LOG)
#define BLOCK_ALIGN_M1 (BLOCK_ALIGN - 1)
/* Default value for the maximum size of the database files. */
#define DEFAULT_MAX_DB_SIZE (32 * 1024 * 1024)

3
nscd/nscd_helper.c
View file

@ -481,6 +481,7 @@ __nscd_cache_search (request_type type, const char *key, size_t keylen,
ref_t trail = mapped->head->array[hash];
trail = atomic_forced_read (trail);
ref_t work = trail;
size_t loop_cnt = datasize / (offsetof (struct datahead, data) + datalen);
int tick = 0;
while (work != ENDREF && work + sizeof (struct hashentry) <= datasize)
@ -527,7 +528,7 @@ __nscd_cache_search (request_type type, const char *key, size_t keylen,
work = atomic_forced_read (here->next);
/* Prevent endless loops. This should never happen but perhaps
the database got corrupted, accidentally or deliberately. */
if (work == trail)
if (work == trail || loop_cnt-- > 0)
break;
if (tick)
{