ubusd_id.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <unistd.h>
   4 #include <fcntl.h>
   5
   6 #include "ubusmsg.h"
   7 #include "ubusd_id.h"
   8
   9 static int random_fd = -1;
  10
  11 static int ubus_cmp_id(const void *k1, const void *k2, void *ptr)
  12 {
  13         const uint32_t *id1 = k1, *id2 = k2;
  14
  15         if (*id1 < *id2)
  16                 return -1;
  17         else
  18                 return *id1 > *id2;
  19 }
  20
  21 void ubus_init_id_tree(struct avl_tree *tree)
  22 {
  23         if (random_fd < 0) {
  24                 random_fd = open("/dev/urandom", O_RDONLY);
  25                 if (random_fd < 0) {
  26                         perror("open");
  27                         exit(1);
  28                 }
  29         }
  30
  31         avl_init(tree, ubus_cmp_id, false, NULL);
  32 }
  33
  34 bool ubus_alloc_id(struct avl_tree *tree, struct ubus_id *id, uint32_t val)
  35 {
  36         id->avl.key = &id->id;
  37         if (val) {
  38                 id->id = val;
  39                 return avl_insert(tree, &id->avl) == 0;
  40         }
  41
  42         do {
  43                 if (read(random_fd, &id->id, sizeof(id->id)) != sizeof(id->id))
  44                         return false;
  45
  46                 if (id->id < UBUS_SYSTEM_OBJECT_MAX)
  47                         continue;
  48         } while (avl_insert(tree, &id->avl) != 0);
  49
  50         return true;
  51 }
  52