ssize_t my_write(int fd, const void *buf, size_t count)
{
//获取真实地址
typedef ssize_t (*REALFUNC)(int fd, const void *buf, size_t count);
REALFUNC real_write = (REALFUNC)get_real_func("write");
//忽略标准输入/输出
if(fd >=0 && fd <= 2) {
return real_write(fd, buf, count);
}
//通过fd获取文件名并过滤
char filename[256];
getfilename(fd, filename, sizeof(filename));
char *fname = "data.txt";
//判断文件名是否为"data.txt"，如果不是则调用原函数
if(strncmp(filename, fname, strlen(fname)) != 0) {
return real_write(fd, buf, count);
}
//考虑到printf实际内部会调用write函数，避免循环调用，执行printf前先detach之后再attach
detach_func("write");
printf("[%s] fd:%d(%s), buf:%s\n", __FUNCTION__, fd, filename, buf);
attach_func("write", (void *)my_write);
errno = ENOSPC;
return -1;
}
/*
* Temporary work around until we have real reference counting
*
* We keep the bits about calling dlil_if_release (which should be
* called recycle) transparent by calling it from our if_free function
* pointer. We have to keep the client's original detach function
* somewhere so we can call it.
*/
static void
ifnet_kpi_free(ifnet_t ifp)
{
ifnet_detached_func detach_func = ifp->if_kpi_storage;
if (detach_func != NULL)
detach_func(ifp);
if (ifp->if_broadcast.length > sizeof (ifp->if_broadcast.u.buffer)) {
FREE(ifp->if_broadcast.u.ptr, M_IFADDR);
ifp->if_broadcast.u.ptr = NULL;
}
dlil_if_release(ifp);
}
