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#include <string.h>
#include <stdio.h>
#include "lock.h"
/* ************ Locking functions ***************** */
#ifndef FSP_NOLOCKING
static char code_str[] =
"0123456789:_ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
static void make_key_string( FSP_LOCK *lock,
unsigned long server_addr,
unsigned long server_port)
{
unsigned long v1, v2;
char *p;
strcpy(lock->key_string,FSP_KEY_PREFIX);
for(p = lock->key_string; *p; p++);
v1 = server_addr;
v2 = server_port;
*p++ = code_str[v1 & 0x3f]; v1 >>= 6;
*p++ = code_str[v1 & 0x3f]; v1 >>= 6;
*p++ = code_str[v1 & 0x3f]; v1 >>= 6;
v1 = v1 | (v2 << (32-3*6));
*p++ = code_str[v1 & 0x3f]; v1 >>= 6;
*p++ = code_str[v1 & 0x3f]; v1 >>= 6;
*p++ = code_str[v1 & 0x3f]; v1 >>= 6;
*p++ = code_str[v1 & 0x3f]; v1 >>= 6;
*p++ = code_str[v1 & 0x3f]; v1 >>= 6;
*p = 0;
}
#endif
/********************************************************************/
/******* For those systems that has SysV shared memory + semop ******/
/********************************************************************/
#ifdef FSP_USE_SHAREMEM_AND_SEMOP
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <sys/sem.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>
#ifdef _SEM_SEMUN_UNDEFINED
union semun
{
int val;
struct semid_ds *buf;
unsigned short int *array;
struct seminfo *__buf;
};
#endif
unsigned short client_get_key (FSP_LOCK *lock)
{
struct sembuf sem;
sem.sem_num = 0;
sem.sem_op = -1;
sem.sem_flg = SEM_UNDO;
if(semop(lock->lock_sem,&sem,1) == -1 )
{
perror("semop lock");
}
return(*lock->share_key);
}
void client_set_key (FSP_LOCK *lock,unsigned short key)
{
struct sembuf sem;
sem.sem_num = 0;
sem.sem_op = 1;
sem.sem_flg = SEM_UNDO;
*lock->share_key = key;
if(semop(lock->lock_sem,&sem,1) == -1) {
perror("semop unlock");
}
}
int client_init_key (FSP_LOCK *lock,
unsigned long server_addr,
unsigned short server_port)
{
mode_t omask;
key_t lock_key;
int fd;
union semun su;
struct sembuf sem;
make_key_string(lock,server_addr,server_port);
omask = umask(0);
fd = open(lock->key_string,O_RDWR|O_CREAT,0666);
umask(omask);
close(fd);
if((lock_key = ftok(lock->key_string,238)) == -1) {
perror("ftok");
return -1;
}
if((lock->lock_shm = shmget(lock_key,2*sizeof(unsigned int),IPC_CREAT|0666)) == -1) {
perror("shmget");
return -1;
}
if(!(lock->share_key = (unsigned int *) shmat(lock->lock_shm,NULL,0))) {
perror("shmat");
return -1;
}
if((lock->lock_sem = semget(lock_key,0,0)) == -1) {
/* create a new semaphore and init it */
if((lock->lock_sem = semget(lock_key,2,IPC_CREAT|0666)) == -1) {
perror("semget");
return -1;
}
/* we need to init this semaphore */
su.val=1;
if(semctl(lock->lock_sem,0,SETVAL,su) == -1)
{
perror("semctl setval");
return -1;
}
}
/* increase in use counter */
sem.sem_num = 1;
sem.sem_op = 1;
sem.sem_flg = SEM_UNDO;
if(semop(lock->lock_sem,&sem,1) == -1) {
perror("semop incuse");
}
return 0;
}
void client_destroy_key(FSP_LOCK *lock)
{
int rc;
struct sembuf sem;
if (shmdt(lock->share_key) < 0)
{
perror("shmdt");
return;
}
/* check if we are only one process holding lock */
rc = semctl(lock->lock_sem,1,GETVAL);
if (rc == 1)
{
/* safe to destroy */
if (
(semctl(lock->lock_sem,0,IPC_RMID) < 0) ||
(shmctl(lock->lock_shm,IPC_RMID,NULL) < 0) ||
(unlink(lock->key_string) < 0) )
rc=0;/* ignore cleanup errors */
}
else
if(rc > 1)
{
/* we need to decrease sem. */
sem.sem_num = 1;
sem.sem_op = -1;
sem.sem_flg = SEM_UNDO;
if(semop(lock->lock_sem,&sem,1) == -1) {
perror("semop decuse");
}
}
}
#endif
/********************************************************************/
/******* For those who do not want to use locking *******************/
/********************************************************************/
#ifdef FSP_NOLOCKING
unsigned short client_get_key (FSP_LOCK *lock)
{
return lock->share_key;
}
void client_set_key (FSP_LOCK *lock,unsigned short key)
{
lock->share_key=key;
}
int client_init_key (FSP_LOCK *lock,
unsigned long server_addr,
unsigned short server_port)
{
return 0;
}
void client_destroy_key(FSP_LOCK *lock)
{
return;
}
#endif
/********************************************************************/
/******* For those systems that has lockf function call *************/
/********************************************************************/
#ifdef FSP_USE_LOCKF
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
unsigned short client_get_key (FSP_LOCK *lock)
{
unsigned int okey;
if (lockf(lock->lock_fd, F_LOCK, sizeof(okey)) < 0)
{
perror("lockf");
}
if (read(lock->lock_fd, &okey, sizeof(okey)) < 0)
{
perror("readlk");
}
if (lseek(lock->lock_fd, 0L, 0) < 0)
{
perror("seek");
}
return(okey);
}
void client_set_key (FSP_LOCK *lock,unsigned short nkey)
{
unsigned int key;
key=nkey;
if (write(lock->lock_fd, &key, sizeof(key)) < 0)
{
perror("write");
}
if (lseek(lock->lock_fd, 0L, 0) < 0)
{
perror("seek");
}
if (lockf(lock->lock_fd, F_ULOCK, sizeof(key)) < 0)
{
perror("unlockf");
}
}
int client_init_key (FSP_LOCK *lock,
unsigned long server_addr,
unsigned short server_port)
{
mode_t omask;
make_key_string(lock,server_addr, server_port);
omask = umask(0);
lock->lock_fd = open(lock->key_string, O_RDWR | O_CREAT, 0666);
(void)umask(omask);
if(lock->lock_fd < 0)
return -1;
else
return 0;
}
void
client_destroy_key(FSP_LOCK *lock)
{
(void)close(lock->lock_fd);
}
#endif
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