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