libs/lmo/src/lmo_core.c

   1 /*
   2  * lmo - Lua Machine Objects - Base functions
   3  *
   4  *   Copyright (C) 2009 Jo-Philipp Wich <xm@subsignal.org>
   5  *
   6  *  Licensed under the Apache License, Version 2.0 (the "License");
   7  *  you may not use this file except in compliance with the License.
   8  *  You may obtain a copy of the License at
   9  *
  10  *      http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  *  Unless required by applicable law or agreed to in writing, software
  13  *  distributed under the License is distributed on an "AS IS" BASIS,
  14  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  *  See the License for the specific language governing permissions and
  16  *  limitations under the License.
  17  */
  18
  19 #include "lmo.h"
  20
  21 extern char _lmo_error[1024];
  22
  23 static int lmo_read32( int fd, uint32_t *val )
  24 {
  25         uint8_t buffer[5];
  26
  27         if( read(fd, buffer, 4) < 4 )
  28                 return -1;
  29
  30         buffer[4] = 0;
  31         *val = ntohl(*((uint32_t *) buffer));
  32
  33         return 4;
  34 }
  35
  36 static char * error(const char *message, int add_errno)
  37 {
  38         memset(_lmo_error, 0, sizeof(_lmo_error));
  39
  40         if( add_errno )
  41                 snprintf(_lmo_error, sizeof(_lmo_error),
  42                         "%s: %s", message, strerror(errno));
  43         else
  44                 snprintf(_lmo_error, sizeof(_lmo_error), "%s", message);
  45
  46         return NULL;
  47 }
  48
  49 const char * lmo_error(void)
  50 {
  51         return _lmo_error;
  52 }
  53
  54 lmo_archive_t * lmo_open(const char *file)
  55 {
  56         int in = -1;
  57         uint32_t idx_offset = 0;
  58         uint32_t i;
  59         struct stat s;
  60
  61         lmo_archive_t *ar    = NULL;
  62         lmo_entry_t   *head  = NULL;
  63         lmo_entry_t   *entry = NULL;
  64
  65         if( stat(file, &s) == -1 )
  66         {
  67                 error("Can not stat file", 1);
  68                 goto cleanup;
  69         }
  70
  71         if( (in = open(file, O_RDONLY)) == -1 )
  72         {
  73                 error("Can not open file", 1);
  74                 goto cleanup;
  75         }
  76
  77         if( lseek(in, -sizeof(uint32_t), SEEK_END) == -1 )
  78         {
  79                 error("Can not seek to eof", 1);
  80                 goto cleanup;
  81         }
  82
  83         if( lmo_read32(in, &idx_offset) != 4 )
  84         {
  85                 error("Unexpected EOF while reading index offset", 0);
  86                 goto cleanup;
  87         }
  88
  89         if( lseek(in, idx_offset, SEEK_SET) == -1 )
  90         {
  91                 error("Can not seek to index offset", 1);
  92                 goto cleanup;
  93         }
  94
  95         if( (ar = (lmo_archive_t *) malloc(sizeof(lmo_archive_t))) != NULL )
  96         {
  97                 ar->fd     = in;
  98                 ar->length = idx_offset;
  99
 100                 for( i = idx_offset;
 101                      i < (s.st_size - sizeof(uint32_t));
 102                      i += (4 * sizeof(uint32_t))
 103                 ) {
 104                         if( (entry = (lmo_entry_t *) malloc(sizeof(lmo_entry_t))) != NULL )
 105                         {
 106                                 if( (lmo_read32(ar->fd, &entry->key_id) == 4) &&
 107                                     (lmo_read32(ar->fd, &entry->val_id) == 4) &&
 108                                     (lmo_read32(ar->fd, &entry->offset) == 4) &&
 109                                     (lmo_read32(ar->fd, &entry->length) == 4)
 110                                 ) {
 111                                         entry->next = head;
 112                                         head = entry;
 113                                 }
 114                                 else
 115                                 {
 116                                         error("Unexpected EOF while reading index entry", 0);
 117                                         goto cleanup;
 118                                 }
 119                         }
 120                         else
 121                         {
 122                                 error("Out of memory", 0);
 123                                 goto cleanup;
 124                         }
 125                 }
 126
 127                 ar->index = head;
 128
 129                 if( lseek(ar->fd, 0, SEEK_SET) == -1 )
 130                 {
 131                         error("Can not seek to start", 1);
 132                         goto cleanup;
 133                 }
 134
 135                 if( (ar->mmap = mmap(NULL, ar->length, PROT_READ, MAP_PRIVATE, ar->fd, 0)) == MAP_FAILED )
 136                 {
 137                         error("Failed to memory map archive contents", 1);
 138                         goto cleanup;
 139                 }
 140
 141                 return ar;
 142         }
 143         else
 144         {
 145                 error("Out of memory", 0);
 146                 goto cleanup;
 147         }
 148
 149
 150         cleanup:
 151
 152         if( in > -1 )
 153                 close(in);
 154
 155         if( head != NULL )
 156         {
 157                 entry = head;
 158
 159                 while( entry != NULL )
 160                 {
 161                         head = entry->next;
 162                         free(entry);
 163                         entry = head;
 164                 }
 165
 166                 head = entry = NULL;
 167         }
 168
 169         if( ar != NULL )
 170         {
 171                 if( (ar->mmap != NULL) && (ar->mmap != MAP_FAILED) )
 172                         munmap(ar->mmap, ar->length);
 173
 174                 free(ar);
 175                 ar = NULL;
 176         }
 177
 178         return NULL;
 179 }
 180
 181 void lmo_close(lmo_archive_t *ar)
 182 {
 183         lmo_entry_t *head  = NULL;
 184         lmo_entry_t *entry = NULL;
 185
 186         if( ar != NULL )
 187         {
 188                 entry = ar->index;
 189
 190                 while( entry != NULL )
 191                 {
 192                         head = entry->next;
 193                         free(entry);
 194                         entry = head;
 195                 }
 196
 197                 head = entry = NULL;
 198
 199                 if( (ar->mmap != NULL) && (ar->mmap != MAP_FAILED) )
 200                         munmap(ar->mmap, ar->length);
 201
 202                 close(ar->fd);
 203                 free(ar);
 204
 205                 ar = NULL;
 206         }
 207 }
 208
 209 int lmo_lookup(lmo_archive_t *ar, const char *key, char *dest, int len)
 210 {
 211         uint32_t look_key = sfh_hash(key, strlen(key));
 212         int copy_len = -1;
 213
 214         lmo_entry_t *entry = ar->index;
 215
 216         while( entry != NULL )
 217         {
 218                 if( entry->key_id == look_key )
 219                 {
 220                         copy_len = (len > entry->length) ? entry->length : len;
 221                         memcpy(dest, &ar->mmap[entry->offset], copy_len);
 222
 223                         break;
 224                 }
 225
 226                 entry = entry->next;
 227         }
 228
 229         return copy_len;
 230 }
 231