LXR busybox/libbb/inode

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * Utility routines.
   4 *
   5 * Copyright (C) many different people.
   6 * If you wrote this, please acknowledge your work.
   7 *
   8 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   9 */
  10
  11#include "libbb.h"
  12
  13typedef struct ino_dev_hash_bucket_struct {
  14        struct ino_dev_hash_bucket_struct *next;
  15        ino_t ino;
  16        dev_t dev;
  17        char name[1];
  18} ino_dev_hashtable_bucket_t;
  19
  20#define HASH_SIZE      311   /* Should be prime */
  21#define hash_inode(i)  ((i) % HASH_SIZE)
  22
  23/* array of [HASH_SIZE] elements */
  24static ino_dev_hashtable_bucket_t **ino_dev_hashtable;
  25
  26/*
  27 * Return name if statbuf->st_ino && statbuf->st_dev are recorded in
  28 * ino_dev_hashtable, else return NULL
  29 */
  30char* FAST_FUNC is_in_ino_dev_hashtable(const struct stat *statbuf)
  31{
  32        ino_dev_hashtable_bucket_t *bucket;
  33
  34        if (!ino_dev_hashtable)
  35                return NULL;
  36
  37        bucket = ino_dev_hashtable[hash_inode(statbuf->st_ino)];
  38        while (bucket != NULL) {
  39                if ((bucket->ino == statbuf->st_ino)
  40                 && (bucket->dev == statbuf->st_dev)
  41                ) {
  42                        return bucket->name;
  43                }
  44                bucket = bucket->next;
  45        }
  46        return NULL;
  47}
  48
  49/* Add statbuf to statbuf hash table */
  50void FAST_FUNC add_to_ino_dev_hashtable(const struct stat *statbuf, const char *name)
  51{
  52        int i;
  53        ino_dev_hashtable_bucket_t *bucket;
  54
  55        i = hash_inode(statbuf->st_ino);
  56        if (!name)
  57                name = "";
  58        bucket = xmalloc(sizeof(ino_dev_hashtable_bucket_t) + strlen(name));
  59        bucket->ino = statbuf->st_ino;
  60        bucket->dev = statbuf->st_dev;
  61        strcpy(bucket->name, name);
  62
  63        if (!ino_dev_hashtable)
  64                ino_dev_hashtable = xzalloc(HASH_SIZE * sizeof(*ino_dev_hashtable));
  65
  66        bucket->next = ino_dev_hashtable[i];
  67        ino_dev_hashtable[i] = bucket;
  68}
  69
  70#if ENABLE_DU || ENABLE_FEATURE_CLEAN_UP
  71/* Clear statbuf hash table */
  72void FAST_FUNC reset_ino_dev_hashtable(void)
  73{
  74        int i;
  75        ino_dev_hashtable_bucket_t *bucket;
  76
  77        for (i = 0; ino_dev_hashtable && i < HASH_SIZE; i++) {
  78                while (ino_dev_hashtable[i] != NULL) {
  79                        bucket = ino_dev_hashtable[i]->next;
  80                        free(ino_dev_hashtable[i]);
  81                        ino_dev_hashtable[i] = bucket;
  82                }
  83        }
  84        free(ino_dev_hashtable);
  85        ino_dev_hashtable = NULL;
  86}
  87#endif
  88