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/*
* proc_devtree.c - handles /proc/device-tree
*
* Copyright 1997 Paul Mackerras
*/
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <asm/prom.h>
#include <asm/uaccess.h>
static struct proc_dir_entry *proc_device_tree;
/*
* Supply data on a read from /proc/device-tree/node/property.
*/
static int property_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
struct property *pp = data;
int n;
if (off >= pp->length) {
*eof = 1;
return 0;
}
n = pp->length - off;
if (n > count)
n = count;
else
*eof = 1;
memcpy(page, pp->value + off, n);
*start = page;
return n;
}
/*
* For a node with a name like "gc@10", we make symlinks called "gc"
* and "@10" to it.
*/
static int devtree_readlink(struct dentry *, char *, int);
static struct dentry *devtree_follow_link(struct dentry *, struct dentry *, unsigned int);
struct inode_operations devtree_symlink_inode_operations = {
NULL, /* no file-operations */
NULL, /* create */
NULL, /* lookup */
NULL, /* link */
NULL, /* unlink */
NULL, /* symlink */
NULL, /* mkdir */
NULL, /* rmdir */
NULL, /* mknod */
NULL, /* rename */
devtree_readlink, /* readlink */
devtree_follow_link, /* follow_link */
NULL, /* readpage */
NULL, /* writepage */
NULL, /* bmap */
NULL, /* truncate */
NULL, /* permission */
NULL /* smap */
};
static struct dentry *devtree_follow_link(struct dentry *dentry,
struct dentry *base,
unsigned int follow)
{
struct inode *inode = dentry->d_inode;
struct proc_dir_entry * de;
char *link;
de = (struct proc_dir_entry *) inode->u.generic_ip;
link = (char *) de->data;
return lookup_dentry(link, base, follow);
}
static int devtree_readlink(struct dentry *dentry, char *buffer, int buflen)
{
struct inode *inode = dentry->d_inode;
struct proc_dir_entry * de;
char *link;
int linklen;
de = (struct proc_dir_entry *) inode->u.generic_ip;
link = (char *) de->data;
linklen = strlen(link);
if (linklen > buflen)
linklen = buflen;
if (copy_to_user(buffer, link, linklen))
return -EFAULT;
return linklen;
}
/*
* Process a node, adding entries for its children and its properties.
*/
static void add_node(struct device_node *np, struct proc_dir_entry *de)
{
struct property *pp;
struct proc_dir_entry *ent;
struct device_node *child, *sib;
const char *p, *at;
int l;
struct proc_dir_entry *list, **lastp, *al;
lastp = &list;
for (pp = np->properties; pp != 0; pp = pp->next) {
/*
* Unfortunately proc_register puts each new entry
* at the beginning of the list. So we rearrange them.
*/
ent = kmalloc(sizeof(struct proc_dir_entry), GFP_KERNEL);
if (ent == 0)
break;
memset(ent, 0, sizeof(struct proc_dir_entry));
ent->name = pp->name;
ent->namelen = strlen(pp->name);
ent->mode = S_IFREG | S_IRUGO;
ent->nlink = 1;
ent->data = pp;
ent->read_proc = property_read_proc;
ent->size = pp->length;
proc_register(de, ent);
*lastp = ent;
lastp = &ent->next;
}
for (child = np->child; child != 0; child = child->sibling) {
p = strrchr(child->full_name, '/');
if (p == 0)
p = child->full_name;
else
++p;
/* chop off '@0' if the name ends with that */
l = strlen(p);
if (l > 2 && p[l-2] == '@' && p[l-1] == '0')
l -= 2;
ent = kmalloc(sizeof(struct proc_dir_entry), GFP_KERNEL);
if (ent == 0)
break;
memset(ent, 0, sizeof(struct proc_dir_entry));
ent->name = p;
ent->namelen = l;
ent->mode = S_IFDIR | S_IRUGO | S_IXUGO;
ent->nlink = 2;
proc_register(de, ent);
*lastp = ent;
lastp = &ent->next;
add_node(child, ent);
/*
* If we left the address part on the name, consider
* adding symlinks from the name and address parts.
*/
if (p[l] != 0 || (at = strchr(p, '@')) == 0)
continue;
/*
* If this is the first node with a given name property,
* add a symlink with the name property as its name.
*/
for (sib = np->child; sib != child; sib = sib->sibling)
if (strcmp(sib->name, child->name) == 0)
break;
if (sib == child && strncmp(p, child->name, l) != 0) {
al = kmalloc(sizeof(struct proc_dir_entry),
GFP_KERNEL);
if (al == 0)
break;
memset(al, 0, sizeof(struct proc_dir_entry));
al->name = child->name;
al->namelen = strlen(child->name);
al->mode = S_IFLNK | S_IRUGO | S_IXUGO;
al->nlink = 1;
al->data = (void *) ent->name;
al->ops = &devtree_symlink_inode_operations;
proc_register(de, al);
*lastp = al;
lastp = &al->next;
}
/*
* Add another directory with the @address part as its name.
*/
al = kmalloc(sizeof(struct proc_dir_entry), GFP_KERNEL);
if (al == 0)
break;
memset(al, 0, sizeof(struct proc_dir_entry));
al->name = at;
al->namelen = strlen(at);
al->mode = S_IFLNK | S_IRUGO | S_IXUGO;
al->nlink = 1;
al->data = (void *) ent->name;
al->ops = &devtree_symlink_inode_operations;
proc_register(de, al);
*lastp = al;
lastp = &al->next;
}
*lastp = 0;
de->subdir = list;
}
/*
* Called on initialization to set up the /proc/device-tree subtree
*/
void proc_device_tree_init(void)
{
struct device_node *root;
if ( !have_of )
return;
proc_device_tree = create_proc_entry("device-tree", S_IFDIR, 0);
if (proc_device_tree == 0)
return;
root = find_path_device("/");
if (root == 0) {
printk(KERN_ERR "/proc/device-tree: can't find root\n");
return;
}
add_node(root, proc_device_tree);
}
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