// SPDX-License-Identifier: GPL-2.0

  /*

   * debugfs interface for sunrpc
   *
   * (c) 2014 Jeff Layton <jlayton@primarydata.com>
   */
  
  #include <linux/debugfs.h>
  #include <linux/sunrpc/sched.h>
  #include <linux/sunrpc/clnt.h>
  #include "netns.h"
  
  static struct dentry *topdir;
  static struct dentry *rpc_clnt_dir;

  static struct dentry *rpc_xprt_dir;

  unsigned int rpc_inject_disconnect;

  static int
  tasks_show(struct seq_file *f, void *v)
  {
  	u32 xid = 0;
  	struct rpc_task *task = v;
  	struct rpc_clnt *clnt = task->tk_client;
  	const char *rpc_waitq = "none";
  
  	if (RPC_IS_QUEUED(task))
  		rpc_waitq = rpc_qname(task->tk_waitqueue);
  
  	if (task->tk_rqstp)
  		xid = be32_to_cpu(task->tk_rqstp->rq_xid);
  
  	seq_printf(f, "%5u %04x %6d 0x%x 0x%x %8ld %ps %sv%u %s a:%ps q:%s
  ",
  		task->tk_pid, task->tk_flags, task->tk_status,

  		clnt->cl_clid, xid, rpc_task_timeout(task), task->tk_ops,

  		clnt->cl_program->name, clnt->cl_vers, rpc_proc_name(task),
  		task->tk_action, rpc_waitq);
  	return 0;
  }
  
  static void *
  tasks_start(struct seq_file *f, loff_t *ppos)
  	__acquires(&clnt->cl_lock)
  {

  	struct rpc_clnt *clnt = f->private;

  	loff_t pos = *ppos;

  	struct rpc_task *task;

  	spin_lock(&clnt->cl_lock);
  	list_for_each_entry(task, &clnt->cl_tasks, tk_task)
  		if (pos-- == 0)
  			return task;
  	return NULL;
  }
  
  static void *
  tasks_next(struct seq_file *f, void *v, loff_t *pos)
  {

  	struct rpc_clnt *clnt = f->private;

  	struct rpc_task *task = v;
  	struct list_head *next = task->tk_task.next;

  	++*pos;
  
  	/* If there's another task on list, return it */
  	if (next == &clnt->cl_tasks)
  		return NULL;
  	return list_entry(next, struct rpc_task, tk_task);
  }
  
  static void
  tasks_stop(struct seq_file *f, void *v)
  	__releases(&clnt->cl_lock)
  {

  	struct rpc_clnt *clnt = f->private;

  	spin_unlock(&clnt->cl_lock);
  }
  
  static const struct seq_operations tasks_seq_operations = {
  	.start	= tasks_start,
  	.next	= tasks_next,
  	.stop	= tasks_stop,
  	.show	= tasks_show,
  };
  
  static int tasks_open(struct inode *inode, struct file *filp)
  {

  	int ret = seq_open(filp, &tasks_seq_operations);

  	if (!ret) {
  		struct seq_file *seq = filp->private_data;

  		struct rpc_clnt *clnt = seq->private = inode->i_private;

  		if (!atomic_inc_not_zero(&clnt->cl_count)) {
  			seq_release(inode, filp);

  			ret = -EINVAL;
  		}
  	}
  
  	return ret;
  }
  
  static int
  tasks_release(struct inode *inode, struct file *filp)
  {
  	struct seq_file *seq = filp->private_data;

  	struct rpc_clnt *clnt = seq->private;

  	rpc_release_client(clnt);
  	return seq_release(inode, filp);

  }
  
  static const struct file_operations tasks_fops = {
  	.owner		= THIS_MODULE,
  	.open		= tasks_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= tasks_release,
  };

  static int do_xprt_debugfs(struct rpc_clnt *clnt, struct rpc_xprt *xprt, void *numv)
  {
  	int len;
  	char name[24]; /* enough for "../../rpc_xprt/ + 8 hex digits + NULL */
  	char link[9]; /* enough for 8 hex digits + NULL */
  	int *nump = numv;
  
  	if (IS_ERR_OR_NULL(xprt->debugfs))
  		return 0;
  	len = snprintf(name, sizeof(name), "../../rpc_xprt/%s",
  		       xprt->debugfs->d_name.name);
  	if (len > sizeof(name))
  		return -1;
  	if (*nump == 0)
  		strcpy(link, "xprt");
  	else {
  		len = snprintf(link, sizeof(link), "xprt%d", *nump);
  		if (len > sizeof(link))
  			return -1;
  	}

  	debugfs_create_symlink(link, clnt->cl_debugfs, name);

  	(*nump)++;
  	return 0;
  }

  void

  rpc_clnt_debugfs_register(struct rpc_clnt *clnt)
  {

  	int len;

  	char name[9]; /* enough for 8 hex digits + NULL */
  	int xprtnum = 0;

  	len = snprintf(name, sizeof(name), "%x", clnt->cl_clid);
  	if (len >= sizeof(name))

  		return;

  
  	/* make the per-client dir */
  	clnt->cl_debugfs = debugfs_create_dir(name, rpc_clnt_dir);

  
  	/* make tasks file */

  	debugfs_create_file("tasks", S_IFREG | 0400, clnt->cl_debugfs, clnt,
  			    &tasks_fops);

  	rpc_clnt_iterate_for_each_xprt(clnt, do_xprt_debugfs, &xprtnum);

  }
  
  void
  rpc_clnt_debugfs_unregister(struct rpc_clnt *clnt)
  {
  	debugfs_remove_recursive(clnt->cl_debugfs);
  	clnt->cl_debugfs = NULL;
  }

  static int
  xprt_info_show(struct seq_file *f, void *v)
  {
  	struct rpc_xprt *xprt = f->private;
  
  	seq_printf(f, "netid: %s
  ", xprt->address_strings[RPC_DISPLAY_NETID]);
  	seq_printf(f, "addr:  %s
  ", xprt->address_strings[RPC_DISPLAY_ADDR]);
  	seq_printf(f, "port:  %s
  ", xprt->address_strings[RPC_DISPLAY_PORT]);
  	seq_printf(f, "state: 0x%lx
  ", xprt->state);
  	return 0;
  }
  
  static int
  xprt_info_open(struct inode *inode, struct file *filp)
  {
  	int ret;
  	struct rpc_xprt *xprt = inode->i_private;
  
  	ret = single_open(filp, xprt_info_show, xprt);
  
  	if (!ret) {
  		if (!xprt_get(xprt)) {
  			single_release(inode, filp);
  			ret = -EINVAL;
  		}
  	}
  	return ret;
  }
  
  static int
  xprt_info_release(struct inode *inode, struct file *filp)
  {
  	struct rpc_xprt *xprt = inode->i_private;
  
  	xprt_put(xprt);
  	return single_release(inode, filp);
  }
  
  static const struct file_operations xprt_info_fops = {
  	.owner		= THIS_MODULE,
  	.open		= xprt_info_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= xprt_info_release,
  };

  void

  rpc_xprt_debugfs_register(struct rpc_xprt *xprt)
  {
  	int len, id;
  	static atomic_t	cur_id;
  	char		name[9]; /* 8 hex digits + NULL term */
  
  	id = (unsigned int)atomic_inc_return(&cur_id);
  
  	len = snprintf(name, sizeof(name), "%x", id);
  	if (len >= sizeof(name))

  		return;

  
  	/* make the per-client dir */
  	xprt->debugfs = debugfs_create_dir(name, rpc_xprt_dir);

  
  	/* make tasks file */

  	debugfs_create_file("info", S_IFREG | 0400, xprt->debugfs, xprt,
  			    &xprt_info_fops);

  
  	atomic_set(&xprt->inject_disconnect, rpc_inject_disconnect);

  }
  
  void
  rpc_xprt_debugfs_unregister(struct rpc_xprt *xprt)
  {
  	debugfs_remove_recursive(xprt->debugfs);
  	xprt->debugfs = NULL;
  }

  static int
  fault_open(struct inode *inode, struct file *filp)
  {
  	filp->private_data = kmalloc(128, GFP_KERNEL);
  	if (!filp->private_data)
  		return -ENOMEM;
  	return 0;
  }
  
  static int
  fault_release(struct inode *inode, struct file *filp)
  {
  	kfree(filp->private_data);
  	return 0;
  }
  
  static ssize_t
  fault_disconnect_read(struct file *filp, char __user *user_buf,
  		      size_t len, loff_t *offset)
  {
  	char *buffer = (char *)filp->private_data;
  	size_t size;
  
  	size = sprintf(buffer, "%u
  ", rpc_inject_disconnect);
  	return simple_read_from_buffer(user_buf, len, offset, buffer, size);
  }
  
  static ssize_t
  fault_disconnect_write(struct file *filp, const char __user *user_buf,
  		       size_t len, loff_t *offset)
  {
  	char buffer[16];

  	if (len >= sizeof(buffer))
  		len = sizeof(buffer) - 1;

  	if (copy_from_user(buffer, user_buf, len))
  		return -EFAULT;
  	buffer[len] = '\0';
  	if (kstrtouint(buffer, 10, &rpc_inject_disconnect))
  		return -EINVAL;
  	return len;
  }
  
  static const struct file_operations fault_disconnect_fops = {
  	.owner		= THIS_MODULE,
  	.open		= fault_open,
  	.read		= fault_disconnect_read,
  	.write		= fault_disconnect_write,
  	.release	= fault_release,
  };

  void __exit
  sunrpc_debugfs_exit(void)
  {
  	debugfs_remove_recursive(topdir);

  	topdir = NULL;
  	rpc_clnt_dir = NULL;
  	rpc_xprt_dir = NULL;

  }

  void __init

  sunrpc_debugfs_init(void)
  {

  	struct dentry *rpc_fault_dir;

  	topdir = debugfs_create_dir("sunrpc", NULL);

  	rpc_clnt_dir = debugfs_create_dir("rpc_clnt", topdir);

  	rpc_xprt_dir = debugfs_create_dir("rpc_xprt", topdir);

  	rpc_fault_dir = debugfs_create_dir("inject_fault", topdir);
  
  	debugfs_create_file("disconnect", S_IFREG | 0400, rpc_fault_dir, NULL,
  			    &fault_disconnect_fops);

  }