diff options
Diffstat (limited to 'debian/htdig/htdig-3.2.0b6/db/mut_tas.c')
| -rw-r--r-- | debian/htdig/htdig-3.2.0b6/db/mut_tas.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/debian/htdig/htdig-3.2.0b6/db/mut_tas.c b/debian/htdig/htdig-3.2.0b6/db/mut_tas.c new file mode 100644 index 00000000..821818cd --- /dev/null +++ b/debian/htdig/htdig-3.2.0b6/db/mut_tas.c @@ -0,0 +1,168 @@ +/*- + * See the file LICENSE for redistribution information. + * + * Copyright (c) 1996, 1997, 1998, 1999 + * Sleepycat Software. All rights reserved. + */ + +#include "db_config.h" + +#ifdef HAVE_MUTEX_TAS + +#ifndef lint +static const char sccsid[] = "@(#)mut_tas.c 11.4 (Sleepycat) 10/1/99"; +#endif /* not lint */ + +#ifndef NO_SYSTEM_INCLUDES +#include <sys/types.h> + +#include <errno.h> +#include <stdlib.h> +#include <string.h> + +#ifndef _MSC_VER /* _WIN32 */ +#include <unistd.h> +#endif + +#endif + +#include "db_int.h" + +#ifdef HAVE_MUTEX_68K_GCC_ASSEMBLY +#include "68K.gcc" +#endif +#ifdef HAVE_MUTEX_ALPHA_GCC_ASSEMBLY +#include "alpha.gcc" +#endif +#ifdef HAVE_MUTEX_HPPA_GCC_ASSEMBLY +#include "parisc.gcc" +#endif +#ifdef HAVE_MUTEX_SCO_X86_CC_ASSEMBLY +#include "sco.cc" +#endif +#ifdef HAVE_MUTEX_SPARC_GCC_ASSEMBLY +#include "sparc.gcc" +#endif +#ifdef HAVE_MUTEX_X86_GCC_ASSEMBLY +#include "x86.gcc" +#endif + +#ifdef DIAGNOSTIC +#undef MSG1 +#define MSG1 "mutex_lock: ERROR: lock currently in use: pid: %lu.\n" +#undef MSG2 +#define MSG2 "mutex_unlock: ERROR: lock already unlocked\n" +#ifndef STDERR_FILENO +#define STDERR_FILENO 2 +#endif +#endif + +/* + * CDB___db_tas_mutex_init -- + * Initialize a MUTEX. + * + * PUBLIC: int CDB___db_tas_mutex_init __P((DB_ENV *, MUTEX *, u_int32_t)); + */ +int +CDB___db_tas_mutex_init(dbenv, mutexp, flags) + DB_ENV *dbenv; + MUTEX *mutexp; + u_int32_t flags; +{ + memset(mutexp, 0, sizeof(*mutexp)); + + /* + * If this is a thread lock or the process has told us that there are + * no other processes in the environment, use thread-only locks, they + * are faster in some cases. + * + * This is where we decide to ignore locks we don't need to set -- if + * the application isn't threaded, there aren't any threads to block. + */ + if (LF_ISSET(MUTEX_THREAD) || F_ISSET(dbenv, DB_ENV_PRIVATE)) { + if (!F_ISSET(dbenv, DB_ENV_THREAD)) { + F_SET(mutexp, MUTEX_IGNORE); + return (0); + } + F_SET(mutexp, MUTEX_THREAD); + } + + /* Initialize the lock. */ + if (MUTEX_INIT(&mutexp->tas)) + return (CDB___os_get_errno()); + + mutexp->spins = CDB___os_spin(); + + return (0); +} + +/* + * CDB___db_tas_mutex_lock + * Lock on a mutex, logically blocking if necessary. + * + * PUBLIC: int CDB___db_tas_mutex_lock __P((MUTEX *)); + */ +int +CDB___db_tas_mutex_lock(mutexp) + MUTEX *mutexp; +{ + u_long ms; + int nspins; + + if (!DB_GLOBAL(db_mutexlocks) || F_ISSET(mutexp, MUTEX_IGNORE)) + return (0); + + ms = 1; + +loop: /* Attempt to acquire the resource for N spins. */ + for (nspins = mutexp->spins; nspins > 0; --nspins) { + if (!MUTEX_SET(&mutexp->tas)) + continue; +#ifdef DIAGNOSTIC + if (mutexp->locked != 0) { + char msgbuf[128]; + (void)snprintf(msgbuf, + sizeof(msgbuf), MSG1, (u_long)mutexp->locked); + (void)write(STDERR_FILENO, msgbuf, strlen(msgbuf)); + } + mutexp->locked = (u_int32_t)getpid(); +#endif + if (ms == 1) + ++mutexp->mutex_set_nowait; + else + ++mutexp->mutex_set_wait; + return (0); + } + + /* Yield the processor; wait 1ms initially, up to 1 second. */ + CDB___os_yield(ms * USEC_PER_MS); + if ((ms <<= 1) > MS_PER_SEC) + ms = MS_PER_SEC; + + goto loop; +} + +/* + * CDB___db_tas_mutex_unlock -- + * Release a lock. + * + * PUBLIC: int CDB___db_tas_mutex_unlock __P((MUTEX *)); + */ +int +CDB___db_tas_mutex_unlock(mutexp) + MUTEX *mutexp; +{ + if (!DB_GLOBAL(db_mutexlocks) || F_ISSET(mutexp, MUTEX_IGNORE)) + return (0); + +#ifdef DIAGNOSTIC + if (!mutexp->locked) + (void)write(STDERR_FILENO, MSG2, sizeof(MSG2) - 1); + mutexp->locked = 0; +#endif + + MUTEX_UNSET(&mutexp->tas); + + return (0); +} +#endif /* HAVE_MUTEX_TAS */ |