sys_readlink失败EFAULT-替代 [英] sys_readlink fails EFAULT - alternative

问题描述

我的文件描述符，并希望得到真实路径.目前，我叫sys_readlink 其工作的时候，但是往往我得到一个错误-14(-EFAULT).

I have the filedescriptor and like to get the real path. Currently i call sys_readlink /proc/self/fd/<fd> which works sometimes, but often i get an error -14 (-EFAULT).

下面一些代码:

fs = get_fs();
set_fs(KERNEL_DS);
err = sys_readlink(path, buf, size-1);
set_fs(fs);

是否有其他(可能更好)的方式来得到内核?

Is there an alternative (probably better) way to get the realpath from kernel?

推荐答案

这在任务结构，例如在filep得到它像

Get it from the filep in the task struct, e.g. something like

struct task_struct *task;
struct files_struct *files;
struct file *file;
char buf[buflen], *realpath;

task = current /* or some other task */;
get_task_struct(task);
files = get_files_struct(task);
put_task_struct(task);
spin_lock(&files->file_lock);
file = fcheck_files(files, fdno);
realpath = d_path(file->f_path, buf, buflen);
spin_unlock(&files->file_lock);
put_files_struct(files);

错误处理消隐为了简洁.

Error handling elided for brevity.

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