fs/proc/proc_devtree.c

   1 /*
   2  * proc_devtree.c - handles /proc/device-tree
   3  *
   4  * Copyright 1997 Paul Mackerras
   5  */
   6 #include <linux/errno.h>
   7 #include <linux/init.h>
   8 #include <linux/time.h>
   9 #include <linux/proc_fs.h>
  10 #include <linux/seq_file.h>
  11 #include <linux/stat.h>
  12 #include <linux/string.h>
  13 #include <linux/of.h>
  14 #include <linux/module.h>
  15 #include <linux/slab.h>
  16 #include <asm/prom.h>
  17 #include <asm/uaccess.h>
  18 #include "internal.h"
  19
  20 static inline void set_node_proc_entry(struct device_node *np,
  21                                        struct proc_dir_entry *de)
  22 {
  23 #ifdef HAVE_ARCH_DEVTREE_FIXUPS
  24         np->pde = de;
  25 #endif
  26 }
  27
  28 static struct proc_dir_entry *proc_device_tree;
  29
  30 /*
  31  * Supply data on a read from /proc/device-tree/node/property.
  32  */
  33 static int property_proc_show(struct seq_file *m, void *v)
  34 {
  35         struct property *pp = m->private;
  36
  37         seq_write(m, pp->value, pp->length);
  38         return 0;
  39 }
  40
  41 static int property_proc_open(struct inode *inode, struct file *file)
  42 {
  43         return single_open(file, property_proc_show, PDE(inode)->data);
  44 }
  45
  46 static const struct file_operations property_proc_fops = {
  47         .owner          = THIS_MODULE,
  48         .open           = property_proc_open,
  49         .read           = seq_read,
  50         .llseek         = seq_lseek,
  51         .release        = single_release,
  52 };
  53
  54 /*
  55  * For a node with a name like "gc@10", we make symlinks called "gc"
  56  * and "@10" to it.
  57  */
  58
  59 /*
  60  * Add a property to a node
  61  */
  62 static struct proc_dir_entry *
  63 __proc_device_tree_add_prop(struct proc_dir_entry *de, struct property *pp,
  64                 const char *name)
  65 {
  66         struct proc_dir_entry *ent;
  67
  68         /*
  69          * Unfortunately proc_register puts each new entry
  70          * at the beginning of the list.  So we rearrange them.
  71          */
  72         ent = proc_create_data(name,
  73                                strncmp(name, "security-", 9) ? S_IRUGO : S_IRUSR,
  74                                de, &property_proc_fops, pp);
  75         if (ent == NULL)
  76                 return NULL;
  77
  78         if (!strncmp(name, "security-", 9))
  79                 ent->size = 0; /* don't leak number of password chars */
  80         else
  81                 ent->size = pp->length;
  82
  83         return ent;
  84 }
  85
  86
  87 void proc_device_tree_add_prop(struct proc_dir_entry *pde, struct property *prop)
  88 {
  89         __proc_device_tree_add_prop(pde, prop, prop->name);
  90 }
  91
  92 void proc_device_tree_remove_prop(struct proc_dir_entry *pde,
  93                                   struct property *prop)
  94 {
  95         remove_proc_entry(prop->name, pde);
  96 }
  97
  98 void proc_device_tree_update_prop(struct proc_dir_entry *pde,
  99                                   struct property *newprop,
 100                                   struct property *oldprop)
 101 {
 102         struct proc_dir_entry *ent;
 103
 104         for (ent = pde->subdir; ent != NULL; ent = ent->next)
 105                 if (ent->data == oldprop)
 106                         break;
 107         if (ent == NULL) {
 108                 printk(KERN_WARNING "device-tree: property \"%s\" "
 109                        " does not exist\n", oldprop->name);
 110         } else {
 111                 ent->data = newprop;
 112                 ent->size = newprop->length;
 113         }
 114 }
 115
 116 /*
 117  * Various dodgy firmware might give us nodes and/or properties with
 118  * conflicting names. That's generally ok, except for exporting via /proc,
 119  * so munge names here to ensure they're unique.
 120  */
 121
 122 static int duplicate_name(struct proc_dir_entry *de, const char *name)
 123 {
 124         struct proc_dir_entry *ent;
 125         int found = 0;
 126
 127         spin_lock(&proc_subdir_lock);
 128
 129         for (ent = de->subdir; ent != NULL; ent = ent->next) {
 130                 if (strcmp(ent->name, name) == 0) {
 131                         found = 1;
 132                         break;
 133                 }
 134         }
 135
 136         spin_unlock(&proc_subdir_lock);
 137
 138         return found;
 139 }
 140
 141 static const char *fixup_name(struct device_node *np, struct proc_dir_entry *de,
 142                 const char *name)
 143 {
 144         char *fixed_name;
 145         int fixup_len = strlen(name) + 2 + 1; /* name + #x + \0 */
 146         int i = 1, size;
 147
 148 realloc:
 149         fixed_name = kmalloc(fixup_len, GFP_KERNEL);
 150         if (fixed_name == NULL) {
 151                 printk(KERN_ERR "device-tree: Out of memory trying to fixup "
 152                                 "name \"%s\"\n", name);
 153                 return name;
 154         }
 155
 156 retry:
 157         size = snprintf(fixed_name, fixup_len, "%s#%d", name, i);
 158         size++; /* account for NULL */
 159
 160         if (size > fixup_len) {
 161                 /* We ran out of space, free and reallocate. */
 162                 kfree(fixed_name);
 163                 fixup_len = size;
 164                 goto realloc;
 165         }
 166
 167         if (duplicate_name(de, fixed_name)) {
 168                 /* Multiple duplicates. Retry with a different offset. */
 169                 i++;
 170                 goto retry;
 171         }
 172
 173         printk(KERN_WARNING "device-tree: Duplicate name in %s, "
 174                         "renamed to \"%s\"\n", np->full_name, fixed_name);
 175
 176         return fixed_name;
 177 }
 178
 179 /*
 180  * Process a node, adding entries for its children and its properties.
 181  */
 182 void proc_device_tree_add_node(struct device_node *np,
 183                                struct proc_dir_entry *de)
 184 {
 185         struct property *pp;
 186         struct proc_dir_entry *ent;
 187         struct device_node *child;
 188         const char *p;
 189
 190         set_node_proc_entry(np, de);
 191         for (child = NULL; (child = of_get_next_child(np, child));) {
 192                 /* Use everything after the last slash, or the full name */
 193                 p = strrchr(child->full_name, '/');
 194                 if (!p)
 195                         p = child->full_name;
 196                 else
 197                         ++p;
 198
 199                 if (duplicate_name(de, p))
 200                         p = fixup_name(np, de, p);
 201
 202                 ent = proc_mkdir(p, de);
 203                 if (ent == NULL)
 204                         break;
 205                 proc_device_tree_add_node(child, ent);
 206         }
 207         of_node_put(child);
 208
 209         for (pp = np->properties; pp != NULL; pp = pp->next) {
 210                 p = pp->name;
 211
 212                 if (strchr(p, '/'))
 213                         continue;
 214
 215                 if (duplicate_name(de, p))
 216                         p = fixup_name(np, de, p);
 217
 218                 ent = __proc_device_tree_add_prop(de, pp, p);
 219                 if (ent == NULL)
 220                         break;
 221         }
 222 }
 223
 224 /*
 225  * Called on initialization to set up the /proc/device-tree subtree
 226  */
 227 void __init proc_device_tree_init(void)
 228 {
 229         struct device_node *root;
 230
 231         proc_device_tree = proc_mkdir("device-tree", NULL);
 232         if (proc_device_tree == NULL)
 233                 return;
 234         root = of_find_node_by_path("/");
 235         if (root == NULL) {
 236                 pr_debug("/proc/device-tree: can't find root\n");
 237                 return;
 238         }
 239         proc_device_tree_add_node(root, proc_device_tree);
 240         of_node_put(root);
 241 }