original development tree for Linux kernel GTP module; now long in mainline.
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/*
* 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))
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;
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\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) {
pr_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;
}
pr_warn("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 = 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) {
pr_debug("/proc/device-tree: can't find root\n");
return;
}
proc_device_tree_add_node(root, proc_device_tree);
of_node_put(root);
}