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Use FNV-1A hash to generate unique mutex names

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For Windows and MacOSX
This commit is contained in:
Howard Chu 2011-09-15 10:36:15 -07:00
parent 2c033676ea
commit 0a28548131
1 changed files with 82 additions and 21 deletions
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103
libraries/libmdb/mdb.c
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@ -2022,6 +2022,80 @@ mdb_env_share_locks(MDB_env *env)
}
#endif
}
#if defined(_WIN32) || defined(__APPLE__)
/*
* hash_64 - 64 bit Fowler/Noll/Vo-0 FNV-1a hash code
*
* @(#) $Revision: 5.1 $
* @(#) $Id: hash_64a.c,v 5.1 2009/06/30 09:01:38 chongo Exp $
* @(#) $Source: /usr/local/src/cmd/fnv/RCS/hash_64a.c,v $
*
* http://www.isthe.com/chongo/tech/comp/fnv/index.html
*
***
*
* Please do not copyright this code. This code is in the public domain.
*
* LANDON CURT NOLL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
* EVENT SHALL LANDON CURT NOLL BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
* USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*
* By:
* chongo <Landon Curt Noll> /\oo/\
* http://www.isthe.com/chongo/
*
* Share and Enjoy! :-)
*/
typedef unsigned long long mdb_hash_t;
#define MDB_HASH_INIT ((mdb_hash_t)0xcbf29ce484222325ULL)
/** perform a 64 bit Fowler/Noll/Vo FNV-1a hash on a buffer
* @param[in] str string to hash
* @param[in] hval initial value for hash
* @return 64 bit hash
*
* NOTE: To use the recommended 64 bit FNV-1a hash, use MDB_HASH_INIT as the
* hval arg on the first call.
*/
static inline mdb_hash_t
mdb_hash_str(char *str, mdb_hash_t hval)
{
unsigned char *s = (unsigned char *)str; /* unsigned string */
/*
* FNV-1a hash each octet of the string
*/
while (*s) {
/* xor the bottom with the current octet */
hval ^= (mdb_hash_t)*s++;
/* multiply by the 64 bit FNV magic prime mod 2^64 */
hval += (hval << 1) + (hval << 4) + (hval << 5) +
(hval << 7) + (hval << 8) + (hval << 40);
}
/* return our new hash value */
return hval;
}
/** Hash the string and output the hash in hex.
* @param[in] str string to hash
* @param[out] hexbuf an array of 17 chars to hold the hash
*/
static void
mdb_hash_hex(char *str, char *hexbuf)
{
int i;
mdb_hash_t h = mdb_hash_str(str, MDB_HASH_INIT);
for (i=0; i<8; i++) {
hexbuf += sprintf(hexbuf, "%02x", (unsigned int)h & 0xff);
h >>= 8;
}
}
#endif
/** Open and/or initialize the lock region for the environment.
* @param[in] env The MDB environment.
@ -2135,7 +2209,7 @@ mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
#endif
if (*excl) {
#ifdef _WIN32
char *ptr;
char hexbuf[17];
if (!mdb_sec_inited) {
InitializeSecurityDescriptor(&mdb_null_sd,
SECURITY_DESCRIPTOR_REVISION);
@ -2145,22 +2219,14 @@ mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
mdb_all_sa.lpSecurityDescriptor = &mdb_null_sd;
mdb_sec_inited = 1;
}
/* FIXME: only using up to 20 characters of the env path here,
* probably not enough to assure uniqueness...
*/
sprintf(env->me_txns->mti_rmname, "Global\\MDBr%.20s", lpath);
ptr = env->me_txns->mti_rmname + sizeof("Global\\MDBr")-1;
while ((ptr = strchr(ptr, '\\')))
*ptr++ = '/';
mdb_hash_hex(lpath, hexbuf);
sprintf(env->me_txns->mti_rmname, "Global\\MDBr%s", hexbuf);
env->me_rmutex = CreateMutex(&mdb_all_sa, FALSE, env->me_txns->mti_rmname);
if (!env->me_rmutex) {
rc = ErrCode();
goto fail;
}
sprintf(env->me_txns->mti_wmname, "Global\\MDBw%.20s", lpath);
ptr = env->me_txns->mti_wmname + sizeof("Global\\MDBw")-1;
while ((ptr = strchr(ptr, '\\')))
*ptr++ = '/';
sprintf(env->me_txns->mti_wmname, "Global\\MDBw%s", hexbuf);
env->me_wmutex = CreateMutex(&mdb_all_sa, FALSE, env->me_txns->mti_wmname);
if (!env->me_wmutex) {
rc = ErrCode();
@ -2168,11 +2234,9 @@ mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
}
#else /* _WIN32 */
#ifdef __APPLE__
char *ptr;
sprintf(env->me_txns->mti_rmname, "MDBr%.26s", lpath);
ptr = env->me_txns->mti_rmname + sizeof("MDBr")-1;
while ((ptr = strchr(ptr, '/')))
*ptr++ = '_';
char hexbuf[17];
mdb_hash_hex(lpath, hexbuf);
sprintf(env->me_txns->mti_rmname, "MDBr%s", hexbuf);
if (sem_unlink(env->me_txns->mti_rmname)) {
rc = ErrCode();
if (rc != ENOENT && rc != EINVAL)
@ -2183,10 +2247,7 @@ mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
rc = ErrCode();
goto fail;
}
sprintf(env->me_txns->mti_wmname, "MDBw%.26s", lpath);
ptr = env->me_txns->mti_wmname + sizeof("MDBw")-1;
while ((ptr = strchr(ptr, '/')))
*ptr++ = '_';
sprintf(env->me_txns->mti_wmname, "MDBw%s", hexbuf);
if (sem_unlink(env->me_txns->mti_wmname)) {
rc = ErrCode();
if (rc != ENOENT && rc != EINVAL)