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        ino_t ino;
  15        dev_t dev;
  16        /*
  17         * Above fields can be 64-bit, while pointer may be 32-bit.
  18         * Putting "next" field here may reduce size of this struct:
  19         */
  20        struct ino_dev_hash_bucket_struct *next;
  21        /*
  22         * Reportedly, on cramfs a file and a dir can have same ino.
  23         * Need to also remember "file/dir" bit:
  24         */
  25        char isdir; /* bool */
  26        char name[1];
  27} ino_dev_hashtable_bucket_t;
  28
  29#define HASH_SIZE      311u   /* Should be prime */
  30#define hash_inode(i)  ((unsigned)(i) % HASH_SIZE)
  31
  32/* array of [HASH_SIZE] elements */
  33static ino_dev_hashtable_bucket_t **ino_dev_hashtable;
  34
  35/*
  36 * Return name if statbuf->st_ino && statbuf->st_dev are recorded in
  37 * ino_dev_hashtable, else return NULL
  38 */
  39char* FAST_FUNC is_in_ino_dev_hashtable(const struct stat *statbuf)
  40{
  41        ino_dev_hashtable_bucket_t *bucket;
  42
  43        if (!ino_dev_hashtable)
  44                return NULL;
  45
  46        bucket = ino_dev_hashtable[hash_inode(statbuf->st_ino)];
  47        while (bucket != NULL) {
  48                if ((bucket->ino == statbuf->st_ino)
  49                 && (bucket->dev == statbuf->st_dev)
  50                 && (bucket->isdir == !!S_ISDIR(statbuf->st_mode))
  51                ) {
  52                        return bucket->name;
  53                }
  54                bucket = bucket->next;
  55        }
  56        return NULL;
  57}
  58
  59/* Add statbuf to statbuf hash table */
  60void FAST_FUNC add_to_ino_dev_hashtable(const struct stat *statbuf, const char *name)
  61{
  62        int i;
  63        ino_dev_hashtable_bucket_t *bucket;
  64
  65        if (!name)
  66                name = "";
  67        bucket = xmalloc(sizeof(ino_dev_hashtable_bucket_t) + strlen(name));
  68        bucket->ino = statbuf->st_ino;
  69        bucket->dev = statbuf->st_dev;
  70        bucket->isdir = !!S_ISDIR(statbuf->st_mode);
  71        strcpy(bucket->name, name);
  72
  73        if (!ino_dev_hashtable)
  74                ino_dev_hashtable = xzalloc(HASH_SIZE * sizeof(*ino_dev_hashtable));
  75
  76        i = hash_inode(statbuf->st_ino);
  77        bucket->next = ino_dev_hashtable[i];
  78        ino_dev_hashtable[i] = bucket;
  79}
  80
  81#if ENABLE_DU || ENABLE_FEATURE_CLEAN_UP
  82/* Clear statbuf hash table */
  83void FAST_FUNC reset_ino_dev_hashtable(void)
  84{
  85        int i;
  86        ino_dev_hashtable_bucket_t *bucket, *next;
  87
  88        if (!ino_dev_hashtable)
  89                return;
  90
  91        for (i = 0; i < HASH_SIZE; i++) {
  92                bucket = ino_dev_hashtable[i];
  93
  94                while (bucket != NULL) {
  95                        next = bucket->next;
  96                        free(bucket);
  97                        bucket = next;
  98                }
  99        }
 100        free(ino_dev_hashtable);
 101        ino_dev_hashtable = NULL;
 102}
 103#endif
 104