aboutsummaryrefslogtreecommitdiffstats
path: root/fs/proc/proc_devtree.c
blob: f8650dce74fb069c6a66a497c4933cc50e630539 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
/*
 * 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/stat.h>
#include <linux/string.h>
#include <linux/of.h>
#include <linux/module.h>
#include <asm/prom.h>
#include <asm/uaccess.h>
#include "internal.h"

static inline void set_node_proc_entry(struct device_node *np,
				       struct proc_dir_entry *de)
{
#ifdef HAVE_ARCH_DEVTREE_FIXUPS
	np->pde = de;
#endif
}

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(inode)->data);
}

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))
		ent->size = 0; /* don't leak number of password chars */
	else
		ent->size = 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;

	for (ent = pde->subdir; ent != NULL; ent = ent->next)
		if (ent->data == oldprop)
			break;
	if (ent == NULL) {
		printk(KERN_WARNING "device-tree: property \"%s\" "
		       " does not exist\n", 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) {
		printk(KERN_ERR "device-tree: Out of memory trying to fixup "
				"name \"%s\"\n", 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;
	}

	printk(KERN_WARNING "device-tree: Duplicate name in %s, "
			"renamed to \"%s\"\n", 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 = strrchr(child->full_name, '/');
		if (!p)
			p = child->full_name;
		else
			++p;

		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 (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) {
		printk(KERN_ERR "/proc/device-tree: can't find root\n");
		return;
	}
	proc_device_tree_add_node(root, proc_device_tree);
	of_node_put(root);
}