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/time.h>
   8 #include <linux/proc_fs.h>
   9 #include <linux/stat.h>
  10 #include <linux/string.h>
  11 #include <asm/prom.h>
  12 #include <asm/uaccess.h>
  13
  14 #ifndef HAVE_ARCH_DEVTREE_FIXUPS
  15 static inline void set_node_proc_entry(struct device_node *np, struct proc_dir_entry *de)
  16 {
  17 }
  18
  19 static void inline set_node_name_link(struct device_node *np, struct proc_dir_entry *de)
  20 {
  21 }
  22
  23 static void inline set_node_addr_link(struct device_node *np, struct proc_dir_entry *de)
  24 {
  25 }
  26 #endif
  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_read_proc(char *page, char **start, off_t off,
  34                               int count, int *eof, void *data)
  35 {
  36         struct property *pp = data;
  37         int n;
  38
  39         if (off >= pp->length) {
  40                 *eof = 1;
  41                 return 0;
  42         }
  43         n = pp->length - off;
  44         if (n > count)
  45                 n = count;
  46         else
  47                 *eof = 1;
  48         memcpy(page, pp->value + off, n);
  49         *start = page;
  50         return n;
  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  * Process a node, adding entries for its children and its properties.
  60  */
  61 void proc_device_tree_add_node(struct device_node *np, struct proc_dir_entry *de)
  62 {
  63         struct property *pp;
  64         struct proc_dir_entry *ent;
  65         struct device_node *child, *sib;
  66         const char *p, *at;
  67         int l;
  68         struct proc_dir_entry *list, **lastp, *al;
  69
  70         set_node_proc_entry(np, de);
  71         lastp = &list;
  72         for (pp = np->properties; pp != 0; pp = pp->next) {
  73                 /*
  74                  * Unfortunately proc_register puts each new entry
  75                  * at the beginning of the list.  So we rearrange them.
  76                  */
  77                 ent = create_proc_read_entry(pp->name, strncmp(pp->name, "security-", 9) ?
  78                                              S_IRUGO : S_IRUSR, de, property_read_proc, pp);
  79                 if (ent == 0)
  80                         break;
  81                 if (!strncmp(pp->name, "security-", 9))
  82                      ent->size = 0; /* don't leak number of password chars */
  83                 else
  84                      ent->size = pp->length;
  85                 *lastp = ent;
  86                 lastp = &ent->next;
  87         }
  88         child = NULL;
  89         while ((child = of_get_next_child(np, child))) {
  90                 p = strrchr(child->full_name, '/');
  91                 if (!p)
  92                         p = child->full_name;
  93                 else
  94                         ++p;
  95                 /* chop off '@0' if the name ends with that */
  96                 l = strlen(p);
  97                 if (l > 2 && p[l-2] == '@' && p[l-1] == '0')
  98                         l -= 2;
  99                 ent = proc_mkdir(p, de);
 100                 if (ent == 0)
 101                         break;
 102                 *lastp = ent;
 103                 lastp = &ent->next;
 104                 proc_device_tree_add_node(child, ent);
 105
 106                 /*
 107                  * If we left the address part on the name, consider
 108                  * adding symlinks from the name and address parts.
 109                  */
 110                 if (p[l] != 0 || (at = strchr(p, '@')) == 0)
 111                         continue;
 112
 113                 /*
 114                  * If this is the first node with a given name property,
 115                  * add a symlink with the name property as its name.
 116                  */
 117                 sib = NULL;
 118                 while ((sib = of_get_next_child(np, sib)) && sib != child)
 119                         if (sib->name && strcmp(sib->name, child->name) == 0)
 120                                 break;
 121                 if (sib == child && strncmp(p, child->name, l) != 0) {
 122                         al = proc_symlink(child->name, de, ent->name);
 123                         if (al == 0) {
 124                                 of_node_put(sib);
 125                                 break;
 126                         }
 127                         set_node_name_link(child, al);
 128                         *lastp = al;
 129                         lastp = &al->next;
 130                 }
 131                 of_node_put(sib);
 132                 /*
 133                  * Add another directory with the @address part as its name.
 134                  */
 135                 al = proc_symlink(at, de, ent->name);
 136                 if (al == 0)
 137                         break;
 138                 set_node_addr_link(child, al);
 139                 *lastp = al;
 140                 lastp = &al->next;
 141         }
 142         of_node_put(child);
 143         *lastp = NULL;
 144         de->subdir = list;
 145 }
 146
 147 /*
 148  * Called on initialization to set up the /proc/device-tree subtree
 149  */
 150 void proc_device_tree_init(void)
 151 {
 152         struct device_node *root;
 153         if ( !have_of )
 154                 return;
 155         proc_device_tree = proc_mkdir("device-tree", NULL);
 156         if (proc_device_tree == 0)
 157                 return;
 158         root = of_find_node_by_path("/");
 159         if (root == 0) {
 160                 printk(KERN_ERR "/proc/device-tree: can't find root\n");
 161                 return;
 162         }
 163         proc_device_tree_add_node(root, proc_device_tree);
 164         of_node_put(root);
 165 }