root/fs/proc/proc_devtree.c

DEFINITIONS

1. set_node_proc_entry
2. property_read_proc
3. __proc_device_tree_add_prop
4. proc_device_tree_add_prop
5. proc_device_tree_remove_prop
6. proc_device_tree_update_prop
7. duplicate_name
8. fixup_name
9. proc_device_tree_add_node
10. proc_device_tree_init

/*
 * proc_devtree.c - handles /proc/device-tree
 *
 * Copyright 1997 Paul Mackerras
 */
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <asm/prom.h>
#include <asm/uaccess.h>

#ifndef HAVE_ARCH_DEVTREE_FIXUPS
static inline void set_node_proc_entry(struct device_node *np,
                                       struct proc_dir_entry *de)
{
}
#endif

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, (char *)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.
 */

/*
 * 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 = create_proc_read_entry(name,
                                     strncmp(name, "security-", 9)
                                     ? S_IRUGO : S_IRUSR, de,
                                     property_read_proc, 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 == 0)
                        break;
                proc_device_tree_add_node(child, ent);
        }
        of_node_put(child);

        for (pp = np->properties; pp != 0; 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 == 0)
                        break;
        }
}

/*
 * 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 = proc_mkdir("device-tree", NULL);
        if (proc_device_tree == 0)
                return;
        root = of_find_node_by_path("/");
        if (root == 0) {
                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);
}