/*************************************************************************
    > File Name : ipc_share_mem_write.c
    > Author : TL Song
    > EMail : songtianlun@frytea.com
    > Created Time : Wed 30 Dec 2020 03:17:00 PM CST
 ************************************************************************/

#include <stdio.h>
#include <sys/shm.h>
#include <unistd.h>
#include <string.h>

int main(int argc, char ** argv)
{
    key_t key = ftok("/dev/shm/myshm2",0);
    int shm_id = shmget(key, 0x400000, IPC_CREAT | 0666);
    char *p = (char *)shmat(shm_id, NULL, 0);
    char cIndex = 'A';
    int i = 0;
    for(i=0;i<100;i++){
        memset(p, cIndex++, 0x400000);
        printf("Write '%c' to mem '%p'\n", *p, p);
        sleep(1);
    }
    shmdt(p);
    return 0;
}

/*************************************************************************
    > File Name : ipc_share_mem_read.c
    > Author : TL Song
    > EMail : songtianlun@frytea.com
    > Created Time : Wed 30 Dec 2020 03:22:20 PM CST
 ************************************************************************/

#include <stdio.h>
#include <unistd.h>
#include <sys/shm.h>

int main(int argc, char ** argv)
{
    key_t key = ftok("/dev/shm/myshm2", 0);
    int shm_id = shmget(key, 0x400000, 0666);
    char *p = (char *)shmat(shm_id, NULL, 0);
    int i = 0;
    for(i = 0 ;i < 100; i++)
    {
        printf("Read '%c' in mem '%p'\n", *p, p);
        sleep(1);
    }
    shmdt(p);
    return 0;
}

$ gcc ipc_share_mem_write.c -o ipc_share_mem_write
$ gcc ipc_share_mem_read.c -o ipc_share_mem_read
$ touch /dev/shm/myshm2

# 在两个终端分别执行程序即可。

[root@criu_go ~]# free
              total        used        free      shared  buff/cache   available
Mem:        3880732     3193512      421660        9216      265560      461624
Swap:       4063228           0     4063228
[root@criu_go ~]# free
              total        used        free      shared  buff/cache   available
Mem:        3880732     3193744      417308       13312      269680      457292

/*************************************************************************
    > File Name : ipc_share_mem_posix_write.c
    > Author : TL Song
    > EMail : songtianlun@frytea.com
    > Created Time : Wed 30 Dec 2020 03:17:00 PM CST
 ************************************************************************/

#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int main(int argc, char ** argv)
{
    int fd = shm_open("posixsm", O_CREAT | O_RDWR, 0666);
    ftruncate(fd, 0x400000);
    
    char *p = mmap(NULL, 0x400000, PROT_READ| PROT_WRITE, MAP_SHARED, fd, 0);
    char cIndex = 'A';
    int i = 0;
    for(i=0;i<100;i++){
        memset(p, cIndex++, 0x400000);
        printf("Write '%c' to mem '%p'\n", *p, p);
        sleep(1);
    }
    munmap(p, 0x400000);
    return 0;
}

/*************************************************************************
    > File Name : ipc_share_mem_posix_read.c
    > Author : TL Song
    > EMail : songtianlun@frytea.com
    > Created Time : Wed 30 Dec 2020 03:22:20 PM CST
 ************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>

int main(int argc, char ** argv)
{
    int fd = shm_open("posixsm", O_RDONLY, 0666);
    ftruncate(fd, 0x400000);

    char *p = mmap(NULL, 0x400000, PROT_READ, MAP_SHARED, fd, 0);
    int i = 0;
    for(i = 0 ;i < 100; i++)
    {
        printf("Read '%c' in mem '%p'\n", *p, p);
        sleep(1);
    }
    munmap(p, 0x400000);
    return 0;
}

$ gcc ipc_share_mem_posix_write.c -o ipc_share_mem_posix_write -lrt
$ gcc ipc_share_mem_posix_read.c -o ipc_share_mem_posix_read -lrt

# 在两个终端分别执行程序即可。

Task 4526 with SysVIPC shmem map @7fdff5956000 doesn't live in IPC ns

$ yum install criu -y 
$ criu check
Looks good.

# 获取进程 PID
$ ps -ef | grep ipc
root     15748 15340  0 10:56 pts/1    00:00:00 ./checkpoint_demo
root     15751 15479  0 10:56 pts/2    00:00:00 grep --color=auto checkpoint_demo

# 对进程打快照
$ criu dump -D ./migrate_imgs/ -j -t 15748

# 略去拷贝快照文件夹的步骤，自行拷贝至目标机器任意位置即可

# 拷贝共享内存文件至目标位置
$ scp /dev/shm/posixsm root@192.168.7.48:/dev/shm/posixsm 

# 拷贝程序文件至目标位置，注意迁移前后的程序和依赖文件的路径必须保持一致
$ scp PracticeDev/clang/ipc_test/ipc_share_mem_posix_write root@192.168.7.48:/root/PracticeDev/clang/ipc_test

# 恢复进程状态
$ criu restore -D ./migrate_imgs/ -j