Further robustify nscd database lookup.

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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@ -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.

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@ -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

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@ -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)

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@ -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)
{