/*
   * proc_devtree.c - handles /proc/device-tree
   *
   * Copyright 1997 Paul Mackerras
   */
  #include <linux/errno.h>
  #include <linux/init.h>
  #include <linux/time.h>
  #include <linux/proc_fs.h>
  #include <linux/seq_file.h>
  #include <linux/printk.h>
  #include <linux/stat.h>
  #include <linux/string.h>
  #include <linux/of.h>
  #include <linux/export.h>
  #include <linux/slab.h>
  #include <asm/uaccess.h>
  #include "internal.h"
  
  static inline void set_node_proc_entry(struct device_node *np,
  				       struct proc_dir_entry *de)
  {
  	np->pde = de;
  }
  
  static struct proc_dir_entry *proc_device_tree;
  
  /*
   * Supply data on a read from /proc/device-tree/node/property.
   */
  static int property_proc_show(struct seq_file *m, void *v)
  {
  	struct property *pp = m->private;
  
  	seq_write(m, pp->value, pp->length);
  	return 0;
  }
  
  static int property_proc_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, property_proc_show, __PDE_DATA(inode));
  }
  
  static const struct file_operations property_proc_fops = {
  	.owner		= THIS_MODULE,
  	.open		= property_proc_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= single_release,
  };
  
  /*
   * For a node with a name like "gc@10", we make symlinks called "gc"
   * and "@10" to it.
   */
  
  /*
   * Add a property to a node
   */
  static struct proc_dir_entry *
  __proc_device_tree_add_prop(struct proc_dir_entry *de, struct property *pp,
  		const char *name)
  {
  	struct proc_dir_entry *ent;
  
  	/*
  	 * Unfortunately proc_register puts each new entry
  	 * at the beginning of the list.  So we rearrange them.
  	 */
  	ent = proc_create_data(name,
  			       strncmp(name, "security-", 9) ? S_IRUGO : S_IRUSR,
  			       de, &property_proc_fops, pp);
  	if (ent == NULL)
  		return NULL;
  
  	if (!strncmp(name, "security-", 9))
  		proc_set_size(ent, 0); /* don't leak number of password chars */
  	else
  		proc_set_size(ent, pp->length);
  
  	return ent;
  }
  
  
  void proc_device_tree_add_prop(struct proc_dir_entry *pde, struct property *prop)
  {
  	__proc_device_tree_add_prop(pde, prop, prop->name);
  }
  
  void proc_device_tree_remove_prop(struct proc_dir_entry *pde,
  				  struct property *prop)
  {
  	remove_proc_entry(prop->name, pde);
  }
  
  void proc_device_tree_update_prop(struct proc_dir_entry *pde,
  				  struct property *newprop,
  				  struct property *oldprop)
  {
  	struct proc_dir_entry *ent;
  
  	if (!oldprop) {
  		proc_device_tree_add_prop(pde, newprop);
  		return;
  	}
  
  	for (ent = pde->subdir; ent != NULL; ent = ent->next)
  		if (ent->data == oldprop)
  			break;
  	if (ent == NULL) {
  		pr_warn("device-tree: property \"%s\" does not exist
  ",
  			oldprop->name);
  	} else {
  		ent->data = newprop;
  		ent->size = newprop->length;
  	}
  }
  
  /*
   * Various dodgy firmware might give us nodes and/or properties with
   * conflicting names. That's generally ok, except for exporting via /proc,
   * so munge names here to ensure they're unique.
   */
  
  static int duplicate_name(struct proc_dir_entry *de, const char *name)
  {
  	struct proc_dir_entry *ent;
  	int found = 0;
  
  	spin_lock(&proc_subdir_lock);
  
  	for (ent = de->subdir; ent != NULL; ent = ent->next) {
  		if (strcmp(ent->name, name) == 0) {
  			found = 1;
  			break;
  		}
  	}
  
  	spin_unlock(&proc_subdir_lock);
  
  	return found;
  }
  
  static const char *fixup_name(struct device_node *np, struct proc_dir_entry *de,
  		const char *name)
  {
  	char *fixed_name;
  	int fixup_len = strlen(name) + 2 + 1; /* name + #x + \0 */
  	int i = 1, size;
  
  realloc:
  	fixed_name = kmalloc(fixup_len, GFP_KERNEL);
  	if (fixed_name == NULL) {
  		pr_err("device-tree: Out of memory trying to fixup "
  		       "name \"%s\"
  ", name);
  		return name;
  	}
  
  retry:
  	size = snprintf(fixed_name, fixup_len, "%s#%d", name, i);
  	size++; /* account for NULL */
  
  	if (size > fixup_len) {
  		/* We ran out of space, free and reallocate. */
  		kfree(fixed_name);
  		fixup_len = size;
  		goto realloc;
  	}
  
  	if (duplicate_name(de, fixed_name)) {
  		/* Multiple duplicates. Retry with a different offset. */
  		i++;
  		goto retry;
  	}
  
  	pr_warn("device-tree: Duplicate name in %s, renamed to \"%s\"
  ",
  		np->full_name, fixed_name);
  
  	return fixed_name;
  }
  
  /*
   * Process a node, adding entries for its children and its properties.
   */
  void proc_device_tree_add_node(struct device_node *np,
  			       struct proc_dir_entry *de)
  {
  	struct property *pp;
  	struct proc_dir_entry *ent;
  	struct device_node *child;
  	const char *p;
  
  	set_node_proc_entry(np, de);
  	for (child = NULL; (child = of_get_next_child(np, child));) {
  		/* Use everything after the last slash, or the full name */
  		p = kbasename(child->full_name);
  
  		if (duplicate_name(de, p))
  			p = fixup_name(np, de, p);
  
  		ent = proc_mkdir(p, de);
  		if (ent == NULL)
  			break;
  		proc_device_tree_add_node(child, ent);
  	}
  	of_node_put(child);
  
  	for (pp = np->properties; pp != NULL; pp = pp->next) {
  		p = pp->name;
  
  		if (strchr(p, '/'))
  			continue;
  
  		if (duplicate_name(de, p))
  			p = fixup_name(np, de, p);
  
  		ent = __proc_device_tree_add_prop(de, pp, p);
  		if (ent == NULL)
  			break;
  	}
  }
  
  /*
   * Called on initialization to set up the /proc/device-tree subtree
   */
  void __init proc_device_tree_init(void)
  {
  	struct device_node *root;
  
  	proc_device_tree = proc_mkdir("device-tree", NULL);
  	if (proc_device_tree == NULL)
  		return;
  	root = of_find_node_by_path("/");
  	if (root == NULL) {
  		remove_proc_entry("device-tree", NULL);
  		pr_debug("/proc/device-tree: can't find root
  ");
  		return;
  	}
  	proc_device_tree_add_node(root, proc_device_tree);
  	of_node_put(root);
  }