Commit 58ddb552 authored by Howard Chu's avatar Howard Chu
Browse files

Use SysV semaphores instead of POSIX

Since they can cleanup after themselves on process exit
parent a53716ed
......@@ -102,7 +102,7 @@ extern int cacheflush(char *addr, int nbytes, int cache);
#endif
#if defined(__APPLE__) || defined (BSD)
# define MDB_USE_POSIX_SEM 1
# define MDB_USE_SYSV_SEM 1
# define MDB_FDATASYNC fsync
#elif defined(ANDROID)
# define MDB_FDATASYNC fsync
......@@ -110,11 +110,18 @@ extern int cacheflush(char *addr, int nbytes, int cache);
#ifndef _WIN32
#include <pthread.h>
#ifdef MDB_USE_POSIX_SEM
# define MDB_USE_HASH 1
#include <semaphore.h>
#endif
#endif
#ifdef MDB_USE_SYSV_SEM
#include <sys/ipc.h>
#include <sys/sem.h>
#ifdef _SEM_SEMUN_UNDEFINED
union semun {
int val;
struct semid_ds *buf;
unsigned short *array;
};
#endif /* _SEM_SEMUN_UNDEFINED */
#endif /* MDB_USE_SYSV_SEM */
#endif /* !_WIN32 */
#ifdef USE_VALGRIND
#include <valgrind/memcheck.h>
......@@ -193,7 +200,7 @@ extern int cacheflush(char *addr, int nbytes, int cache);
#define MDB_DEVEL 0
#endif
#if MDB_DEVEL && (defined(_WIN32) || (defined(EOWNERDEAD) && !defined(MDB_USE_POSIX_SEM)))
#if MDB_DEVEL && (defined(_WIN32) || (defined(EOWNERDEAD) && !defined(MDB_USE_SYSV_SEM)))
#define MDB_ROBUST_SUPPORTED 1
#endif
......@@ -254,25 +261,30 @@ typedef HANDLE mdb_mutex_t;
/** For MDB_LOCK_FORMAT: True if readers take a pid lock in the lockfile */
#define MDB_PIDLOCK 1
#ifdef MDB_USE_POSIX_SEM
#ifdef MDB_USE_SYSV_SEM
typedef sem_t *mdb_mutex_t;
#define MDB_MUTEX(env, rw) ((env)->me_##rw##mutex)
typedef struct mdb_mutex {
int semid;
int semnum;
} mdb_mutex_t;
#define MDB_MUTEX(env, rw) (&(env)->me_##rw##mutex)
#define LOCK_MUTEX0(mutex) mdb_sem_wait(mutex)
#define UNLOCK_MUTEX(mutex) sem_post(mutex)
#define UNLOCK_MUTEX(mutex) do { struct sembuf sb = { mutex->semnum, 1, SEM_UNDO }; semop(mutex->semid, &sb, 1); } while(0)
static int
mdb_sem_wait(sem_t *sem)
mdb_sem_wait(mdb_mutex_t *sem)
{
int rc;
while ((rc = sem_wait(sem)) && (rc = errno) == EINTR) ;
struct sembuf sb = { sem->semnum, -1, SEM_UNDO };
while ((rc = semop(sem->semid, &sb, 1)) && (rc = errno) == EINTR) ;
return rc;
}
#else
/** Pointer/HANDLE type of shared mutex/semaphore.
*/
typedef pthread_mutex_t *mdb_mutex_t;
typedef pthread_mutex_t mdb_mutex_t;
/** Mutex for the reader table (rw = r) or write transaction (rw = w).
*/
#define MDB_MUTEX(env, rw) (&(env)->me_txns->mti_##rw##mutex)
......@@ -283,7 +295,7 @@ typedef pthread_mutex_t *mdb_mutex_t;
/** Unlock the reader or writer mutex.
*/
#define UNLOCK_MUTEX(mutex) pthread_mutex_unlock(mutex)
#endif /* MDB_USE_POSIX_SEM */
#endif /* MDB_USE_SYSV_SEM */
/** Get the error code for the last failed system function.
*/
......@@ -308,8 +320,10 @@ typedef pthread_mutex_t *mdb_mutex_t;
#define GET_PAGESIZE(x) ((x) = sysconf(_SC_PAGE_SIZE))
#endif
#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
#if defined(_WIN32)
#define MNAME_LEN 32
#elif defined(MDB_USE_SYSV_SEM)
#define MNAME_LEN 0
#else
#define MNAME_LEN (sizeof(pthread_mutex_t))
#endif
......@@ -323,7 +337,7 @@ typedef pthread_mutex_t *mdb_mutex_t;
#define LOCK_MUTEX(rc, env, mutex) \
(((rc) = LOCK_MUTEX0(mutex)) && \
((rc) = mdb_mutex_failed(env, mutex, rc)))
static int mdb_mutex_failed(MDB_env *env, mdb_mutex_t mutex, int rc);
static int mdb_mutex_failed(MDB_env *env, mdb_mutex_t *mutex, int rc);
#else
#define LOCK_MUTEX(rc, env, mutex) ((rc) = LOCK_MUTEX0(mutex))
#define mdb_mutex_failed(env, mutex, rc) (rc)
......@@ -636,8 +650,10 @@ 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) || defined(MDB_USE_POSIX_SEM)
#if defined(_WIN32)
char mtb_rmname[MNAME_LEN];
#elif defined(MDB_USE_SYSV_SEM)
int mtb_semid;
#else
/** Mutex protecting access to this table.
* This is the #MDB_MUTEX(env,r) reader table lock.
......@@ -672,9 +688,11 @@ typedef struct MDB_txninfo {
char pad[(sizeof(MDB_txbody)+CACHELINE-1) & ~(CACHELINE-1)];
} mt1;
union {
#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
#if defined(_WIN32)
char mt2_wmname[MNAME_LEN];
#define mti_wmname mt2.mt2_wmname
#elif defined(MDB_USE_SYSV_SEM)
#define mti_semid mt1.mtb.mtb_semid
#else
pthread_mutex_t mt2_wmutex;
#define mti_wmutex mt2.mt2_wmutex
......@@ -1157,8 +1175,8 @@ struct MDB_env {
#ifdef _WIN32
int me_pidquery; /**< Used in OpenProcess */
#endif
#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
/* Windows mutexes/POSIX semaphores do not reside in shared mem */
#if defined(_WIN32) || defined(MDB_USE_SYSV_SEM)
/* Windows mutexes/SysV semaphores do not reside in shared mem */
mdb_mutex_t me_rmutex;
mdb_mutex_t me_wmutex;
#endif
......@@ -1212,7 +1230,7 @@ static int mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata,
static int mdb_env_read_header(MDB_env *env, MDB_meta *meta);
static int mdb_env_pick_meta(const MDB_env *env);
static int mdb_env_write_meta(MDB_txn *txn);
#if !(defined(_WIN32) || defined(MDB_USE_POSIX_SEM)) /* Drop unused excl arg */
#if !(defined(_WIN32) || defined(MDB_USE_SYSV_SEM)) /* Drop unused excl arg */
# define mdb_env_close0(env, excl) mdb_env_close1(env)
#endif
static void mdb_env_close0(MDB_env *env, int excl);
......@@ -2510,7 +2528,7 @@ mdb_txn_renew0(MDB_txn *txn)
} else {
MDB_PID_T pid = env->me_pid;
MDB_THR_T tid = pthread_self();
mdb_mutex_t rmutex = MDB_MUTEX(env, r);
mdb_mutex_t *rmutex = MDB_MUTEX(env, r);
if (!env->me_live_reader) {
rc = mdb_reader_pid(env, Pidset, pid);
......@@ -3695,9 +3713,9 @@ 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_POSIX_SEM
e->me_rmutex = SEM_FAILED;
e->me_wmutex = SEM_FAILED;
#ifdef MDB_USE_SYSV_SEM
e->me_rmutex.semid = -1;
e->me_wmutex.semid = -1;
#endif
e->me_pid = getpid();
GET_PAGESIZE(e->me_os_psize);
......@@ -4080,8 +4098,8 @@ mdb_env_excl_lock(MDB_env *env, int *excl)
if (!rc) {
*excl = 1;
} else
# ifdef MDB_USE_POSIX_SEM
if (*excl < 0) /* always true when !MDB_USE_POSIX_SEM */
# ifdef MDB_USE_SYSV_SEM
if (*excl < 0) /* always true when !MDB_USE_SYSV_SEM */
# endif
{
lock_info.l_type = F_RDLCK;
......@@ -4321,41 +4339,23 @@ mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
env->me_wmutex = CreateMutex(&mdb_all_sa, FALSE, env->me_txns->mti_wmname);
if (!env->me_wmutex) goto fail_errno;
env->me_flags |= MDB_ROBUST;
#elif defined(MDB_USE_POSIX_SEM)
struct stat stbuf;
struct {
dev_t dev;
ino_t ino;
} idbuf;
MDB_val val;
char encbuf[11];
#elif defined(MDB_USE_SYSV_SEM)
union semun semu;
unsigned short vals[2] = {1, 1};
int semid = semget(IPC_PRIVATE, 2, mode);
if (semid < 0)
goto fail_errno;
#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;
#else /* MDB_USE_POSIX_SEM */
env->me_rmutex.semid = semid;
env->me_wmutex.semid = semid;
env->me_rmutex.semnum = 0;
env->me_wmutex.semnum = 1;
semu.array = vals;
if (semctl(semid, 0, SETALL, semu) < 0)
goto fail_errno;
env->me_txns->mti_semid = semid;
#else /* MDB_USE_SYSV_SEM */
pthread_mutexattr_t mattr;
if ((rc = pthread_mutexattr_init(&mattr))
......@@ -4368,7 +4368,7 @@ 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_POSIX_SEM */
#endif /* _WIN32 || MDB_USE_SYSV_SEM */
#ifndef MDB_ROBUST_SUPPORTED
env->me_flags &= ~MDB_ROBUST;
#endif
......@@ -4402,11 +4402,23 @@ 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)
struct semid_ds buf;
union semun semu;
int semid = env->me_txns->mti_semid;
semu.buf = &buf;
/* check for read access */
if (semctl(semid, 0, IPC_STAT, semu) < 0)
goto fail_errno;
/* check for write access */
if (semctl(semid, 0, IPC_SET, semu) < 0)
goto fail_errno;
env->me_rmutex.semid = semid;
env->me_wmutex.semid = semid;
env->me_rmutex.semnum = 0;
env->me_wmutex.semnum = 1;
#endif
}
return MDB_SUCCESS;
......@@ -4642,20 +4654,15 @@ 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);
#elif defined(MDB_USE_SYSV_SEM)
if (env->me_rmutex.semid != -1) {
/* 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);
}
if (excl > 0)
semctl(env->me_rmutex.semid, 0, IPC_RMID);
}
#endif
munmap((void *)env->me_txns, (env->me_maxreaders-1)*sizeof(MDB_reader)+sizeof(MDB_txninfo));
......@@ -8664,7 +8671,7 @@ static int ESECT
mdb_env_copyfd0(MDB_env *env, HANDLE fd)
{
MDB_txn *txn = NULL;
mdb_mutex_t wmutex = NULL;
mdb_mutex_t *wmutex = NULL;
int rc;
size_t wsize;
char *ptr;
......@@ -9415,7 +9422,7 @@ mdb_reader_check(MDB_env *env, int *dead)
/** As #mdb_reader_check(). rlocked = <caller locked the reader mutex>. */
static int mdb_reader_check0(MDB_env *env, int rlocked, int *dead)
{
mdb_mutex_t rmutex = rlocked ? NULL : MDB_MUTEX(env, r);
mdb_mutex_t *rmutex = rlocked ? NULL : MDB_MUTEX(env, r);
unsigned int i, j, rdrs;
MDB_reader *mr;
MDB_PID_T *pids, pid;
......@@ -9472,7 +9479,7 @@ static int mdb_reader_check0(MDB_env *env, int rlocked, int *dead)
* @param[in] rc LOCK_MUTEX0() error (nonzero)
* @return 0 on success with the mutex locked, or an error code on failure.
*/
static int mdb_mutex_failed(MDB_env *env, mdb_mutex_t mutex, int rc)
static int mdb_mutex_failed(MDB_env *env, mdb_mutex_t *mutex, int rc)
{
int toggle, rlocked, rc2;
#ifndef _WIN32
......
......@@ -64,7 +64,7 @@ int main(int argc,char * argv[])
act = "opening environment";
rc = mdb_env_create(&env);
if (rc == MDB_SUCCESS) {
rc = mdb_env_open(env, argv[1], flags, 0664);
rc = mdb_env_open(env, argv[1], flags, 0600);
}
if (rc == MDB_SUCCESS) {
act = "copying";
......
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