ipc.h
#include <sys/types.h>
#include <unistd.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/shm.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h> #ifndef _IPC_H_
#define _IPC_H_ union semun {
int val;
struct semid_ds *buf;
unsigned short *array; struct seminfo *_buf;
}; int sem_create(key_t key);
int sem_open(key_t key); int sem_p(int semid);
int sem_v(int semid);
int sem_d(int semid);
int sem_setval(int semid, int val);
int sem_getval(int semid);
int sem_getmode(int semid);
int sem_setmode(int semid, char* mode); #endif //_IPC_H_
ipc.c
#include "ipc.h" int sem_create(key_t key)
{
int semid = semget(key,, | IPC_CREAT | IPC_EXCL);
if (- == semid)
{
printf("sem create faild\n");
exit();
}
return semid;
}
int sem_open(key_t key)
{
int semid = semget(key,,);
if (- == semid)
{
printf("sem open faild\n");
exit();
}
return semid;
} int sem_p(int semid)
{
struct sembuf sb = {,-,};
int ret = semop(semid,&sb,);
if(- == ret)
{
printf("sem p faild\n");
exit();
}
return ret;
}
int sem_v(int semid)
{
struct sembuf sb = {,,};
int ret = semop(semid,&sb,);
if(- == ret)
{
printf("sem v faild\n");
exit();
}
return ret;
}
int sem_d(int semid)
{
int ret = semctl(semid, , IPC_RMID, );
return ret;
}
int sem_setval(int semid, int val)
{
union semun su;
su.val = val;
int ret = semctl(semid, , SETVAL,su);
if (- == ret)
{
printf("sem setval faild\n");
exit();
}
return ret;
}
int sem_getval(int semid)
{
int ret = semctl(semid, , GETVAL,);
if (- == ret)
{
printf("sem getval faild\n");
exit();
}
return ret;
}
int sem_getmode(int semid)
{
union semun su;
struct semid_ds sem;
su.buf = &sem;
int ret = semctl(semid , , IPC_STAT, su);
if (- == ret)
{
printf("sem getmode failed\n");
exit();
}
printf("current permissions is %o\n",su.buf->sem_perm.mode);
return ret;
}
int sem_setmode(int semid, char* mode)
{
union semun su;
struct semid_ds sem;
su.buf = &sem;
int ret = semctl(semid , , IPC_STAT, su);
if (- == ret)
{
printf("sem getmode failed\n");
exit();
}
printf("current permissions is %o\n",su.buf->sem_perm.mode);
sscanf(mode ,"%o",(unsigned int*)&su.buf->sem_perm.mode);
ret = semctl(semid , , IPC_STAT, su);
if (- == ret)
{
printf("sem getmode failed\n");
exit();
}
printf("permissios update...\n"); return ret;
}
shmfifo.h
#include "ipc.h" #ifndef _SHM_FIFO_H_
#define _SHM_FIFO_H_ typedef struct shmfifo shmfifo_t;
typedef struct shmhead shmhead_t; typedef struct stu
{
char name[];
int age;
}STU; struct shmhead
{
unsigned int blksize; // 块大小
unsigned int blocks; // 总块数
unsigned int rd_index; // 读索引
unsigned int wr_index; // 写索引
}; struct shmfifo
{
shmhead_t *p_shm; // 共享内存头部指针
char *p_payload; // 有效负载的起始地址 int shmid; // 共享内存ID
int sem_mutex; // 用来互斥用的信号量
int sem_full; // 用来控制共享内存是否满的信号量
int sem_empty; // 用来控制共享内存是否空的信号量
}; shmfifo_t* shmfifo_init(int key, int blksize, int blocks);//初始化
void shmfifo_put(shmfifo_t *fifo, const void *buf);//添加数据到环形缓冲区
void shmfifo_get(shmfifo_t *fifo, void *buf);//从缓冲区中取数据
void shmfifo_destroy(shmfifo_t *fifo);//释放共享内存的环形缓冲区 #endif /* _SHM_FIFO_H_ */
shmfifo.c
#include "shmfifo.h"
#include <assert.h> shmfifo_t* shmfifo_init(int key, int blksize, int blocks)
{
//分配内存空间
shmfifo_t *fifo = (shmfifo_t *)malloc(sizeof(shmfifo_t));
assert(fifo != NULL);
memset(fifo, , sizeof(shmfifo_t)); int shmid;
shmid = shmget(key, , );
int size = sizeof(shmhead_t) + blksize*blocks;
if (shmid == -)
{//创建共享内存
fifo->shmid = shmget(key, size, IPC_CREAT | );
if (fifo->shmid == -)
exit(); fifo->p_shm = (shmhead_t*)shmat(fifo->shmid, NULL, );
if (fifo->p_shm == (shmhead_t*)-)
exit(); fifo->p_payload = (char*)(fifo->p_shm + ); //进行字段初始化
fifo->p_shm->blksize = blksize;
fifo->p_shm->blocks = blocks;
fifo->p_shm->rd_index = ;
fifo->p_shm->wr_index = ; fifo->sem_mutex = sem_create(key);
fifo->sem_full = sem_create(key+);
fifo->sem_empty = sem_create(key+); sem_setval(fifo->sem_mutex, );
sem_setval(fifo->sem_full, blocks);
sem_setval(fifo->sem_empty, );
}
else
{//打开共享内存
fifo->shmid = shmid;
fifo->p_shm = (shmhead_t*)shmat(fifo->shmid, NULL, );
if (fifo->p_shm == (shmhead_t*)-)
exit(); fifo->p_payload = (char*)(fifo->p_shm + ); fifo->sem_mutex = sem_open(key);
fifo->sem_full = sem_open(key+);
fifo->sem_empty = sem_open(key+);
} return fifo;
} void shmfifo_put(shmfifo_t *fifo, const void *buf)
{
sem_p(fifo->sem_full);
sem_p(fifo->sem_mutex); //生产产品
memcpy(fifo->p_payload+fifo->p_shm->blksize*fifo->p_shm->wr_index,
buf, fifo->p_shm->blksize);
fifo->p_shm->wr_index = (fifo->p_shm->wr_index + ) % fifo->p_shm->blocks; sem_v(fifo->sem_mutex);
sem_v(fifo->sem_empty);
} void shmfifo_get(shmfifo_t *fifo, void *buf)
{
sem_p(fifo->sem_empty);
sem_p(fifo->sem_mutex); memcpy(buf, fifo->p_payload+fifo->p_shm->blksize*fifo->p_shm->rd_index,
fifo->p_shm->blksize);
fifo->p_shm->rd_index = (fifo->p_shm->rd_index + ) % fifo->p_shm->blocks;
sem_v(fifo->sem_mutex);
sem_v(fifo->sem_full);
} void shmfifo_destroy(shmfifo_t *fifo)
{
//删除创建的信息量集
sem_d(fifo->sem_mutex);
sem_d(fifo->sem_full);
sem_d(fifo->sem_empty); //删除共享内存
shmdt(fifo->p_shm);//删除共享内存头部
shmctl(fifo->shmid, IPC_RMID, );//删除整个共享内存 //释放fifo的内存
free(fifo);
}
shmfifo_send.c
#include "shmfifo.h"
/*
typedef struct stu
{
char name[32];
int age;
}STU;
*/
int main(void)
{
shmfifo_t *fifo = shmfifo_init(,sizeof(STU),); STU s;
memset(&s, , sizeof(STU));
s.name[] = 'A';
int i;
for(i=;i<;i++)
{
s.age = + i;
shmfifo_put(fifo,&s);
s.name[] = s.name[] + ;
printf("send ok\n");
}
return ;
}
shmfifo_recv.c
#include "shmfifo.h"
/*
typedef struct stu
{
char name[32];
int age;
}STU;
*/
int main(void)
{
shmfifo_t *fifo = shmfifo_init(,sizeof(STU),); STU s;
memset(&s, , sizeof(STU)); int i;
for(i=;i<;i++)
{
shmfifo_get(fifo,&s);
printf("name = %s, age = %d\n",s.name,s.age);
}
return ;
}
shmfifo_free.c
#include "shmfifo.h" int main(void)
{
shmfifo_t *fifo = shmfifo_init(,sizeof(STU),);
shmfifo_destroy(fifo);
return ;
}
Makefile
.PHONY:clean all
CC=gcc
CFLAGS=-Wall -g
BIN= shmfifo_send shmfifo_recv shmfifo_free
OBJS1=shmfifo_send.o shmfifo.o ipc.o
OBJS2=shmfifo_recv.o shmfifo.o ipc.o
OBJS3=shmfifo_free.o shmfifo.o ipc.o
all:$(BIN)
%.o:%.c
$(CC) $(CFLAGS) -c $< -o $@
shmfifo_send:$(OBJS1)
$(CC) $(CFLAGS) $^ -o $@
shmfifo_recv:$(OBJS2)
$(CC) $(CFLAGS) $^ -o $@
shmfifo_free:$(OBJS3)
$(CC) $(CFLAGS) $^ -o $@ clean:
rm -f *.o $(BIN)