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