不要调用SYS_readlink
-使用与procfs
读取其中一个链接时相同的方法。开始与代码中proc_pid_readlink()
和proc_fd_link()
的fs/proc/base.c
。
从广义上讲,给予int fd
和struct files_struct *files
从你感兴趣的(你已采取的引用)的任务,你想做的事:
char *tmp;
char *pathname;
struct file *file;
struct path *path;
spin_lock(&files->file_lock);
file = fcheck_files(files, fd);
if (!file) {
spin_unlock(&files->file_lock);
return -ENOENT;
}
path = &file->f_path;
path_get(path);
spin_unlock(&files->file_lock);
tmp = (char *)__get_free_page(GFP_KERNEL);
if (!tmp) {
path_put(path);
return -ENOMEM;
}
pathname = d_path(path, tmp, PAGE_SIZE);
path_put(path);
if (IS_ERR(pathname)) {
free_page((unsigned long)tmp);
return PTR_ERR(pathname);
}
/* do something here with pathname */
free_page((unsigned long)tmp);
如果您的代码在进程上下文中运行(例如,通过syscall调用),并且文件描述符来自当前进程,则可以将其current->files
用于当前任务struct files_struct *
。