tools.c

来自「多用户银行系统」· C语言 代码 · 共 103 行

#include <stddef.h>
#include <signal.h>
#include <sys/types.h>

#include "../include/structs.h"
#include "../include/stddef.h"

int getSHM(){
	
	SHM *shm;
	int shmid;
	
	int index;
	key_t key;
	
	key = ftok("/root/test.c" , 0);	
	//shmid = shmget(key , 0 , 0);
	shmid = shmget(key , SHM_SIZE , 0600);
	shm = shmat(shmid , 0 , 0);

	if(shm->flag == 1)
		return -1;

	shm->flag = 1;
	for(index = 0;index < MAX_CLIENT;index ++){
		if( (shm->swap_arr)[index].flag == 0){
			shm->flag = 0;
			shmdt(shm);
			return index;	
		}	
	}
	shm->flag = 0;
	shmdt(shm);
	return -2;
		
};

int freeSHM(int index){
	SHM *shm;
	int shmid;
	
	//shmid = shmget(KEY , 0 , 0);
	key_t key;
	key = ftok("/root/test.c" , 0);
	shmid = shmget(key , SHM_SIZE , 0600);
	shm = shmat(shmid , 0 , 0);

	(shm->swap_arr)[index].flag = 0;
	
	shmdt(shm);
	return 0;
	
		
};



/*

int getSHM(){
	void *p;
        void *tmp;
	key_t key;
	int shmid;

	key = KEY;
	shmid = shmget(key , 0 , 0);
	//p = shmat(shmid , NULL , 0);
	p = shmat(shmid , NULL , SHM_W|SHM_R);
	tmp = p;
	printf("int getSHM(), SHM's head address : %p\n" , p);
	
	if( *((int *)p) != 0)return -1;
	*(int *)tmp = 1;
	p += sizeof(int);
	while(1){
		if(p - tmp >= SHM_SIZE){
			*(int *)tmp = 0;
			return -1;
		}if(*((int *)p) == 0){
			*((int *)p) = 1;
			p += sizeof(int);
			printf("address of p : %p 	in getSHM()...\n" , p);
			*(int *)tmp = 0;
			return p - tmp;
		}if(*((int*)p) == 1){
			p += sizeof(int);
			p += sizeof(SHM);
			continue;
		}
	}
};


int freeSHM(void *p){
	printf("in freeSHM() , p is : %p\n" , p);
	p -= sizeof(int);
	printf("in freeSHM() , p is : %p\n" , p);
	*(int *)p = 0;
	return OK;
};
*/