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         if( read(fd, val, 4) < 4 )
  26                 return -1;
  27
  28         *val = ntohl(*val);
  29
  30         return 4;
  31 }
  32
  33 static char * error(const char *message, int add_errno)
  34 {
  35         memset(_lmo_error, 0, sizeof(_lmo_error));
  36
  37         if( add_errno )
  38                 snprintf(_lmo_error, sizeof(_lmo_error),
  39                         "%s: %s", message, strerror(errno));
  40         else
  41                 snprintf(_lmo_error, sizeof(_lmo_error), "%s", message);
  42
  43         return NULL;
  44 }
  45
  46 const char * lmo_error(void)
  47 {
  48         return _lmo_error;
  49 }
  50
  51 lmo_archive_t * lmo_open(const char *file)
  52 {
  53         int in = -1;
  54         uint32_t idx_offset = 0;
  55         uint32_t i;
  56         struct stat s;
  57
  58         lmo_archive_t *ar    = NULL;
  59         lmo_entry_t   *head  = NULL;
  60         lmo_entry_t   *entry = NULL;
  61
  62         if( stat(file, &s) == -1 )
  63         {
  64                 error("Can not stat file", 1);
  65                 goto cleanup;
  66         }
  67
  68         if( (in = open(file, O_RDONLY)) == -1 )
  69         {
  70                 error("Can not open file", 1);
  71                 goto cleanup;
  72         }
  73
  74         if( lseek(in, -sizeof(uint32_t), SEEK_END) == -1 )
  75         {
  76                 error("Can not seek to eof", 1);
  77                 goto cleanup;
  78         }
  79
  80         if( lmo_read32(in, &idx_offset) != 4 )
  81         {
  82                 error("Unexpected EOF while reading index offset", 0);
  83                 goto cleanup;
  84         }
  85
  86         if( lseek(in, (off_t)idx_offset, SEEK_SET) == -1 )
  87         {
  88                 error("Can not seek to index offset", 1);
  89                 goto cleanup;
  90         }
  91
  92         if( (ar = (lmo_archive_t *) malloc(sizeof(lmo_archive_t))) != NULL )
  93         {
  94                 ar->fd     = in;
  95                 ar->length = idx_offset;
  96
  97                 for( i = idx_offset;
  98                      i < (s.st_size - sizeof(uint32_t));
  99                      i += (4 * sizeof(uint32_t))
 100                 ) {
 101                         if( (entry = (lmo_entry_t *) malloc(sizeof(lmo_entry_t))) != NULL )
 102                         {
 103                                 if( (lmo_read32(ar->fd, &entry->key_id) == 4) &&
 104                                     (lmo_read32(ar->fd, &entry->val_id) == 4) &&
 105                                     (lmo_read32(ar->fd, &entry->offset) == 4) &&
 106                                     (lmo_read32(ar->fd, &entry->length) == 4)
 107                                 ) {
 108                                         entry->next = head;
 109                                         head = entry;
 110                                 }
 111                                 else
 112                                 {
 113                                         error("Unexpected EOF while reading index entry", 0);
 114                                         goto cleanup;
 115                                 }
 116                         }
 117                         else
 118                         {
 119                                 error("Out of memory", 0);
 120                                 goto cleanup;
 121                         }
 122                 }
 123
 124                 ar->index = head;
 125
 126                 if( lseek(ar->fd, 0, SEEK_SET) == -1 )
 127                 {
 128                         error("Can not seek to start", 1);
 129                         goto cleanup;
 130                 }
 131
 132                 if( (ar->mmap = mmap(NULL, ar->length, PROT_READ, MAP_PRIVATE, ar->fd, 0)) == MAP_FAILED )
 133                 {
 134                         error("Failed to memory map archive contents", 1);
 135                         goto cleanup;
 136                 }
 137
 138                 return ar;
 139         }
 140         else
 141         {
 142                 error("Out of memory", 0);
 143                 goto cleanup;
 144         }
 145
 146
 147         cleanup:
 148
 149         if( in > -1 )
 150                 close(in);
 151
 152         if( head != NULL )
 153         {
 154                 entry = head;
 155
 156                 while( entry != NULL )
 157                 {
 158                         head = entry->next;
 159                         free(entry);
 160                         entry = head;
 161                 }
 162
 163                 head = entry = NULL;
 164         }
 165
 166         if( ar != NULL )
 167         {
 168                 if( (ar->mmap != NULL) && (ar->mmap != MAP_FAILED) )
 169                         munmap(ar->mmap, ar->length);
 170
 171                 free(ar);
 172                 ar = NULL;
 173         }
 174
 175         return NULL;
 176 }
 177
 178 void lmo_close(lmo_archive_t *ar)
 179 {
 180         lmo_entry_t *head  = NULL;
 181         lmo_entry_t *entry = NULL;
 182
 183         if( ar != NULL )
 184         {
 185                 entry = ar->index;
 186
 187                 while( entry != NULL )
 188                 {
 189                         head = entry->next;
 190                         free(entry);
 191                         entry = head;
 192                 }
 193
 194                 head = entry = NULL;
 195
 196                 if( (ar->mmap != NULL) && (ar->mmap != MAP_FAILED) )
 197                         munmap(ar->mmap, ar->length);
 198
 199                 close(ar->fd);
 200                 free(ar);
 201
 202                 ar = NULL;
 203         }
 204 }
 205
 206 int lmo_lookup(lmo_archive_t *ar, const char *key, char *dest, int len)
 207 {
 208         uint32_t look_key = sfh_hash(key, strlen(key));
 209         int copy_len = -1;
 210         lmo_entry_t *entry;
 211
 212         if( !ar )
 213                 return copy_len;
 214
 215         entry = ar->index;
 216
 217         while( entry != NULL )
 218         {
 219                 if( entry->key_id == look_key )
 220                 {
 221                         copy_len = ((len - 1) > entry->length) ? entry->length : (len - 1);
 222                         memcpy(dest, &ar->mmap[entry->offset], copy_len);
 223                         dest[copy_len] = '\0';
 224
 225                         break;
 226                 }
 227
 228                 entry = entry->next;
 229         }
 230
 231         return copy_len;
 232 }
 233