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