Commit 943b23f0 authored by Hallvard Furuseth's avatar Hallvard Furuseth
Browse files

Restore support for Posix semaphores

parent 9574b656
......@@ -8,7 +8,7 @@
# platforms; you should not need to change any of these.
# Read their descriptions in mdb.c if you do:
#
# - MDB_USE_POSIX_SEM
# - MDB_USE_POSIX_MUTEX, MDB_USE_POSIX_SEM, MDB_USE_SYSV_SEM
# - MDB_DSYNC
# - MDB_FDATASYNC
# - MDB_FDATASYNC_WORKS
......
......@@ -57,7 +57,8 @@
* Otherwise just make all programs using the database close it;
* the lockfile is always reset on first open of the environment.
*
* - On BSD systems or others configured with MDB_USE_SYSV_SEM,
* - On BSD systems or others configured with MDB_USE_SYSV_SEM or
* MDB_USE_POSIX_SEM,
* startup can fail due to semaphores owned by another userid.
*
* Fix: Open and close the database as the user which owns the
......
......@@ -110,7 +110,9 @@ extern int cacheflush(char *addr, int nbytes, int cache);
#endif
#if defined(__APPLE__) || defined (BSD)
# if !(defined(MDB_USE_POSIX_MUTEX) || defined(MDB_USE_POSIX_SEM))
# define MDB_USE_SYSV_SEM 1
# endif
# define MDB_FDATASYNC fsync
#elif defined(ANDROID)
# define MDB_FDATASYNC fsync
......@@ -118,7 +120,10 @@ extern int cacheflush(char *addr, int nbytes, int cache);
#ifndef _WIN32
#include <pthread.h>
#ifdef MDB_USE_SYSV_SEM
#ifdef MDB_USE_POSIX_SEM
# define MDB_USE_HASH 1
#include <semaphore.h>
#elif defined(MDB_USE_SYSV_SEM)
#include <sys/ipc.h>
#include <sys/sem.h>
#ifdef _SEM_SEMUN_UNDEFINED
......@@ -130,10 +135,10 @@ union semun {
#endif /* _SEM_SEMUN_UNDEFINED */
#else
#define MDB_USE_POSIX_MUTEX 1
#endif /* MDB_USE_SYSV_SEM */
#endif /* MDB_USE_POSIX_SEM */
#endif /* !_WIN32 */
#if defined(_WIN32) + defined(MDB_USE_SYSV_SEM) \
#if defined(_WIN32) + defined(MDB_USE_POSIX_SEM) + defined(MDB_USE_SYSV_SEM) \
+ defined(MDB_USE_POSIX_MUTEX) != 1
# error "Ambiguous shared-lock implementation"
#endif
......@@ -285,7 +290,21 @@ typedef HANDLE mdb_mutex_t, mdb_mutexref_t;
/** For MDB_LOCK_FORMAT: True if readers take a pid lock in the lockfile */
#define MDB_PIDLOCK 1
#ifdef MDB_USE_SYSV_SEM
#ifdef MDB_USE_POSIX_SEM
typedef sem_t *mdb_mutex_t, *mdb_mutexref_t;
#define LOCK_MUTEX0(mutex) mdb_sem_wait(mutex)
#define UNLOCK_MUTEX(mutex) sem_post(mutex)
static int
mdb_sem_wait(sem_t *sem)
{
int rc;
while ((rc = sem_wait(sem)) && (rc = errno) == EINTR) ;
return rc;
}
#elif defined MDB_USE_SYSV_SEM
typedef struct mdb_mutex {
int semid;
......@@ -339,7 +358,7 @@ typedef pthread_mutex_t mdb_mutex_t[1], *mdb_mutexref_t;
/** Mark mutex-protected data as repaired, after death of previous owner.
*/
#define mdb_mutex_consistent(mutex) pthread_mutex_consistent(mutex)
#endif /* MDB_USE_SYSV_SEM */
#endif /* MDB_USE_POSIX_SEM || MDB_USE_SYSV_SEM */
/** Get the error code for the last failed system function.
*/
......@@ -364,7 +383,7 @@ typedef pthread_mutex_t mdb_mutex_t[1], *mdb_mutexref_t;
#define GET_PAGESIZE(x) ((x) = sysconf(_SC_PAGE_SIZE))
#endif
#if defined(_WIN32)
#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
#define MNAME_LEN 32
#elif defined(MDB_USE_SYSV_SEM)
#define MNAME_LEN (sizeof(int))
......@@ -705,7 +724,7 @@ typedef struct MDB_txbody {
uint32_t mtb_magic;
/** Format of this lock file. Must be set to #MDB_LOCK_FORMAT. */
uint32_t mtb_format;
#if defined(_WIN32)
#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
char mtb_rmname[MNAME_LEN];
#elif defined(MDB_USE_SYSV_SEM)
int mtb_semid;
......@@ -745,7 +764,7 @@ typedef struct MDB_txninfo {
char pad[(sizeof(MDB_txbody)+CACHELINE-1) & ~(CACHELINE-1)];
} mt1;
union {
#if defined(_WIN32)
#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
char mt2_wmname[MNAME_LEN];
#define mti_wmname mt2.mt2_wmname
#elif defined MDB_USE_SYSV_SEM
......@@ -3840,7 +3859,10 @@ mdb_env_create(MDB_env **env)
e->me_fd = INVALID_HANDLE_VALUE;
e->me_lfd = INVALID_HANDLE_VALUE;
e->me_mfd = INVALID_HANDLE_VALUE;
#ifdef MDB_USE_SYSV_SEM
#ifdef MDB_USE_POSIX_SEM
e->me_rmutex = SEM_FAILED;
e->me_wmutex = SEM_FAILED;
#elif defined MDB_USE_SYSV_SEM
e->me_rmutex->semid = -1;
e->me_wmutex->semid = -1;
#endif
......@@ -4556,6 +4578,40 @@ mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
if (!env->me_rmutex) goto fail_errno;
env->me_wmutex = CreateMutex(&mdb_all_sa, FALSE, env->me_txns->mti_wmname);
if (!env->me_wmutex) goto fail_errno;
#elif defined(MDB_USE_POSIX_SEM)
struct stat stbuf;
struct {
dev_t dev;
ino_t ino;
} idbuf;
MDB_val val;
char encbuf[11];
#if defined(__NetBSD__)
#define MDB_SHORT_SEMNAMES 1 /* limited to 14 chars */
#endif
if (fstat(env->me_lfd, &stbuf)) goto fail_errno;
idbuf.dev = stbuf.st_dev;
idbuf.ino = stbuf.st_ino;
val.mv_data = &idbuf;
val.mv_size = sizeof(idbuf);
mdb_hash_enc(&val, encbuf);
#ifdef MDB_SHORT_SEMNAMES
encbuf[9] = '\0'; /* drop name from 15 chars to 14 chars */
#endif
sprintf(env->me_txns->mti_rmname, "/MDBr%s", encbuf);
sprintf(env->me_txns->mti_wmname, "/MDBw%s", encbuf);
/* Clean up after a previous run, if needed: Try to
* remove both semaphores before doing anything else.
*/
sem_unlink(env->me_txns->mti_rmname);
sem_unlink(env->me_txns->mti_wmname);
env->me_rmutex = sem_open(env->me_txns->mti_rmname,
O_CREAT|O_EXCL, mode, 1);
if (env->me_rmutex == SEM_FAILED) goto fail_errno;
env->me_wmutex = sem_open(env->me_txns->mti_wmname,
O_CREAT|O_EXCL, mode, 1);
if (env->me_wmutex == SEM_FAILED) goto fail_errno;
#elif defined(MDB_USE_SYSV_SEM)
unsigned short vals[2] = {1, 1};
key_t key = ftok(lpath, 'M');
......@@ -4580,7 +4636,7 @@ mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
|| (rc = pthread_mutex_init(env->me_txns->mti_wmutex, &mattr)))
goto fail;
pthread_mutexattr_destroy(&mattr);
#endif /* _WIN32 || MDB_USE_SYSV_SEM */
#endif /* _WIN32 || ... */
env->me_txns->mti_magic = MDB_MAGIC;
env->me_txns->mti_format = MDB_LOCK_FORMAT;
......@@ -4611,6 +4667,11 @@ mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
if (!env->me_rmutex) goto fail_errno;
env->me_wmutex = OpenMutex(SYNCHRONIZE, FALSE, env->me_txns->mti_wmname);
if (!env->me_wmutex) goto fail_errno;
#elif defined(MDB_USE_POSIX_SEM)
env->me_rmutex = sem_open(env->me_txns->mti_rmname, 0);
if (env->me_rmutex == SEM_FAILED) goto fail_errno;
env->me_wmutex = sem_open(env->me_txns->mti_wmname, 0);
if (env->me_wmutex == SEM_FAILED) goto fail_errno;
#elif defined(MDB_USE_SYSV_SEM)
semid = env->me_txns->mti_semid;
semu.buf = &buf;
......@@ -4864,6 +4925,21 @@ mdb_env_close0(MDB_env *env, int excl)
/* Windows automatically destroys the mutexes when
* the last handle closes.
*/
#elif defined(MDB_USE_POSIX_SEM)
if (env->me_rmutex != SEM_FAILED) {
sem_close(env->me_rmutex);
if (env->me_wmutex != SEM_FAILED)
sem_close(env->me_wmutex);
/* If we have the filelock: If we are the
* only remaining user, clean up semaphores.
*/
if (excl == 0)
mdb_env_excl_lock(env, &excl);
if (excl > 0) {
sem_unlink(env->me_txns->mti_rmname);
sem_unlink(env->me_txns->mti_wmname);
}
}
#elif defined(MDB_USE_SYSV_SEM)
if (env->me_rmutex->semid != -1) {
/* If we have the filelock: If we are the
......
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