ubusd_id.c

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