diff options
Diffstat (limited to 'src/backend/port/qnx/sem.c')
| -rw-r--r-- | src/backend/port/qnx/sem.c | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/src/backend/port/qnx/sem.c b/src/backend/port/qnx/sem.c new file mode 100644 index 00000000000..c93bc4cf528 --- /dev/null +++ b/src/backend/port/qnx/sem.c @@ -0,0 +1,261 @@ +/*------------------------------------------------------------------------- + * + * sem.c + * System V Semaphore Emulation + * + * Copyright (c) 1999, repas AEG Automation GmbH + * + * + * IDENTIFICATION + * $Header: /cvsroot/pgsql/src/backend/port/qnx/Attic/sem.c,v 1.1 1999/12/16 01:25:06 momjian Exp $ + * + *------------------------------------------------------------------------- + */ + +#include <errno.h> +#include <semaphore.h> +#include <string.h> +#include <sys/types.h> +#include <unistd.h> +#include <fcntl.h> +#include <sys/mman.h> +#include "postgres.h" +#include "storage/ipc.h" +#include <sys/sem.h> + + +#define SETMAX 32 +#define SEMMAX 16 + +#define MODE 0777 +#define SHM_INFO_NAME "SysV_Sem_Info" + + +struct sem_info { + sem_t sem; + struct { + key_t key; + int nsems; + sem_t sem[SEMMAX]; /* array of semaphores */ + pid_t pid[SEMMAX]; /* array of PIDs */ + } set[SETMAX]; +}; + +static struct sem_info *SemInfo = ( struct sem_info * )-1; + + +int semctl( int semid, int semnum, int cmd, /*...*/union semun arg ) +{ + int r; + + sem_wait( &SemInfo->sem ); + + if( semid < 0 || semid >= SETMAX || + semnum < 0 || semnum >= SemInfo->set[semid].nsems ) { + sem_post( &SemInfo->sem ); + errno = EINVAL; + return -1; + } + + switch( cmd ) { + case GETPID: + r = SemInfo->set[semid].pid[semnum]; + break; + + case GETVAL: + r = SemInfo->set[semid].sem[semnum].value; + break; + + case GETALL: + for( semnum = 0; semnum < SemInfo->set[semid].nsems; semnum++ ) { + arg.array[semnum] = SemInfo->set[semid].sem[semnum].value; + } + break; + + case SETVAL: + SemInfo->set[semid].sem[semnum].value = arg.val; + break; + + case SETALL: + for( semnum = 0; semnum < SemInfo->set[semid].nsems; semnum++ ) { + SemInfo->set[semid].sem[semnum].value = arg.array[semnum]; + } + break; + + case IPC_RMID: + for( semnum = 0; semnum < SemInfo->set[semid].nsems; semnum++ ) { + if( sem_destroy( &SemInfo->set[semid].sem[semnum] ) == -1 ) { + r = -1; + } + } + SemInfo->set[semid].key = -1; + SemInfo->set[semid].nsems = 0; + break; + + default: + sem_post( &SemInfo->sem ); + errno = EINVAL; + return -1; + } + + sem_post( &SemInfo->sem ); + + return r; +} + +int semget( key_t key, int nsems, int semflg ) +{ + int fd, semid, semnum/*, semnum1*/; + int exist = 0; + + if( nsems < 0 || nsems > SEMMAX ) { + errno = EINVAL; + return -1; + } + + /* open and map shared memory */ + if( SemInfo == ( struct sem_info * )-1 ) { + /* test if the shared memory already exists */ + fd = shm_open( SHM_INFO_NAME, O_RDWR | O_CREAT | O_EXCL, MODE ); + if( fd == -1 && errno == EEXIST ) { + exist = 1; + fd = shm_open( SHM_INFO_NAME, O_RDWR | O_CREAT, MODE ); + } + if( fd == -1 ) return fd; + /* The size may only be set once. Ignore errors. */ + ltrunc( fd, sizeof( struct sem_info ), SEEK_SET ); + SemInfo = mmap( NULL, sizeof( struct sem_info ), + PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0 ); + if( SemInfo == MAP_FAILED ) return -1; + if( !exist ) { + /* create semaphore for locking */ + sem_init( &SemInfo->sem, 1, 1 ); + sem_wait( &SemInfo->sem ); + /* initilize shared memory */ + memset( SemInfo->set, 0, sizeof( SemInfo->set ) ); + for( semid = 0; semid < SETMAX; semid++ ) { + SemInfo->set[semid].key = -1; + } + sem_post( &SemInfo->sem ); + } + } + + sem_wait( &SemInfo->sem ); + + if( key != IPC_PRIVATE ) { + /* search existing element */ + semid = 0; + while( semid < SETMAX && SemInfo->set[semid].key != key ) semid++; + if( !( semflg & IPC_CREAT ) && semid >= SETMAX ) { + sem_post( &SemInfo->sem ); + errno = ENOENT; + return -1; + } + else if( semid < SETMAX ) { + if( semflg & IPC_CREAT && semflg & IPC_EXCL ) { + sem_post( &SemInfo->sem ); + errno = EEXIST; + return -1; + } + else { + if( nsems != 0 && SemInfo->set[semid].nsems < nsems ) { + sem_post( &SemInfo->sem ); + errno = EINVAL; + return -1; + } + sem_post( &SemInfo->sem ); + return semid; + } + } + } + + /* search first free element */ + semid = 0; + while( semid < SETMAX && SemInfo->set[semid].key != -1 ) semid++; + if( semid >= SETMAX ) { + sem_post( &SemInfo->sem ); + errno = ENOSPC; + return -1; + } + + for( semnum = 0; semnum < nsems; semnum++ ) { + sem_init( &SemInfo->set[semid].sem[semnum], 1, 0 ); +/* Currently sem_init always returns -1. + if( sem_init( &SemInfo->set[semid].sem[semnum], 1, 0 ) == -1 ) { + for( semnum1 = 0; semnum1 < semnum; semnum1++ ) { + sem_destroy( &SemInfo->set[semid].sem[semnum1] ); + } + sem_post( &SemInfo->sem ); + return -1; + } +*/ + } + + SemInfo->set[semid].key = key; + SemInfo->set[semid].nsems = nsems; + + sem_post( &SemInfo->sem ); + + return 0; +} + +int semop( int semid, struct sembuf *sops, size_t nsops ) +{ + int i, j, r = 0, r1, errno1 = 0; + + sem_wait( &SemInfo->sem ); + + if( semid < 0 || semid >= SETMAX ) { + sem_post( &SemInfo->sem ); + errno = EINVAL; + return -1; + } + for( i = 0; i < nsops; i++ ) { + if( /*sops[i].sem_num < 0 ||*/ sops[i].sem_num >= SemInfo->set[semid].nsems ) { + sem_post( &SemInfo->sem ); + errno = EFBIG; + return -1; + } + } + + for( i = 0; i < nsops; i++ ) { + if( sops[i].sem_op < 0 ) { + if( sops[i].sem_flg & IPC_NOWAIT ) { + for( j = 0; j < -sops[i].sem_op; j++ ) { + if( sem_trywait( &SemInfo->set[semid].sem[sops[i].sem_num] ) ) { + errno1 = errno; + r = -1; + } + } + } + else { + for( j = 0; j < -sops[i].sem_op; j++ ) { + sem_post( &SemInfo->sem ); /* avoid deadlock */ + r1 = sem_wait( &SemInfo->set[semid].sem[sops[i].sem_num] ); + sem_wait( &SemInfo->sem ); + if( r1 ) { + errno1 = errno; + r = r1; + } + } + } + } + else if( sops[i].sem_op > 0 ) { + for( j = 0; j < sops[i].sem_op; j++ ) { + if( sem_post( &SemInfo->set[semid].sem[sops[i].sem_num] ) ) { + errno1 = errno; + r = -1; + } + } + } + else /* sops[i].sem_op == 0 */ { + /* not supported */ + } + SemInfo->set[semid].pid[sops[i].sem_num] = getpid( ); + } + + sem_post( &SemInfo->sem ); + + errno = errno1; + return r; +} |