python 读取共享内存

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

int main(int argc, char *argv[])
{
    int        id = 0;
    char    *data =NULL;
    FILE    *fp =NULL;
    int        totle_len = 0;
    int        len = 0;
    char    buf[1024] = {0};
    
    if (argc < 2)
    {
        printf("args too less
");
        return 0;
    }
    
    id = shmget(123559, 21 * 1024 * 1024, IPC_CREAT | 0777);
    if (id < 0)
    {
        printf("get id failed
");
        return 0;
    }
    
    data = shmat(id, NULL, 0);
    if (data ==NULL)
    {
        printf("shamt failed
");
        return 0;
    }
    
    fp = fopen(argv[1], "rb");
    if (fp ==NULL)
    {
        printf("open %s failed
", argv[1]);
        return 0;
    }
    
    while (totle_len <= 12 + 20 * 1024 * 1024)
    {
        len = fread(buf, 1, 1024, fp);
        if (len <= 0)
        {
            break;
        }
        memcpy(data +totle_len, buf, len);
        totle_len +=len;
    }

fclose(fp);    
    return 0;
}

from ctypes import *  
importnumpy as npimportcodecs
importdatetime

SHM_SIZE = 1024*1024*20SHM_KEY = 123559OUTFILE="httpd_cdorked_config.bin"  
try:  
    rt = CDLL('librt.so')  
except:  
    rt = CDLL('librt.so.1')  
shmget =rt.shmget  
shmget.argtypes =[c_int, c_size_t, c_int]  
shmget.restype =c_int  
shmat =rt.shmat  
shmat.argtypes =[c_int, POINTER(c_void_p), c_int]  
shmat.restype =c_void_p  
     
shmid =shmget(SHM_KEY, SHM_SIZE, 0o666)
if shmid <0:  
    print ("System not infected")  
else:   
    begin_time=datetime.datetime.now()
    addr =shmat(shmid, None, 0)  
    f=open(OUTFILE, 'wb')
    rate=int.from_bytes(string_at(addr,4), byteorder='little', signed=True)   #这里数据文件是小端int16类型
    len_a=int.from_bytes(string_at(addr+4,4), byteorder='little', signed=True)   
    len_b=int.from_bytes(string_at(addr+8,4), byteorder='little', signed=True)
    print(rate,len_a,len_b)
    f.write(string_at(addr+12,SHM_SIZE))
    f.close()  #print ("Dumped %d bytes in %s" % (SHM_SIZE, OUTFILE))
print("Success!",datetime.datetime.now()-begin_time)