tools/specmaker/dll.c

   1 /*
   2  *  DLL symbol extraction
   3  *
   4  *  Copyright 2000 Jon Griffiths
   5  */
   6 #include "specmaker.h"
   7
   8 /* DOS/PE Header details */
   9 #define DOS_HEADER_LEN      64
  10 #define DOS_MAGIC           0x5a4d
  11 #define DOS_PE_OFFSET       60
  12 #define PE_HEADER_LEN       248
  13 #define PE_MAGIC            0x4550
  14 #define PE_COUNT_OFFSET     6
  15 #define PE_EXPORTS_OFFSET   120
  16 #define PE_EXPORTS_SIZE     PE_EXPORTS_OFFSET + 4
  17 #define SECTION_HEADER_LEN  40
  18 #define SECTION_ADDR_OFFSET 12
  19 #define SECTION_ADDR_SIZE   SECTION_ADDR_OFFSET + 4
  20 #define SECTION_POS_OFFSET  SECTION_ADDR_SIZE + 4
  21 #define EXPORT_COUNT_OFFSET 24
  22 #define EXPORT_NAME_OFFSET  EXPORT_COUNT_OFFSET + 8
  23
  24 /* Minimum memory needed to read both headers into a buffer */
  25 #define MIN_HEADER_LEN (PE_HEADER_LEN * sizeof (unsigned char))
  26
  27 /* Normalise a pointer in the exports section */
  28 #define REBASE(x) ((x) - exports)
  29
  30 /* Module globals */
  31 static FILE  *dll_file = NULL;
  32 static char **dll_symbols = NULL;
  33 static size_t dll_num_exports = 0;
  34
  35
  36 /* Get a short from a memory block */
  37 static inline size_t get_short (const char *mem)
  38 {
  39   return *((const unsigned char *)mem) +
  40          (*((const unsigned char *)mem + 1) << 8);
  41 }
  42
  43 /* Get an integer from a memory block */
  44 static inline size_t get_int (const char *mem)
  45 {
  46   assert (sizeof (char) == (size_t)1);
  47   return get_short (mem) + (get_short (mem + 2) << 16);
  48 }
  49
  50 static void dll_close (void);
  51
  52
  53 /*******************************************************************
  54  *         dll_open
  55  *
  56  * Open a DLL and read in exported symbols
  57  */
  58 void  dll_open (const char *dll_name)
  59 {
  60   size_t code = 0, code_len = 0, exports, exports_len, count, symbol_data;
  61   char *buff = NULL;
  62   dll_file = open_file (dll_name, ".dll", "r");
  63
  64   atexit (dll_close);
  65
  66   /* Read in the required DOS and PE Headers */
  67   if (!(buff = (char *) malloc (MIN_HEADER_LEN)))
  68     fatal ("Out of memory");
  69
  70   if (fread (buff, DOS_HEADER_LEN, 1, dll_file) != 1 ||
  71       get_short (buff) != DOS_MAGIC)
  72     fatal ("Error reading DOS header");
  73
  74   if (fseek (dll_file, get_int (buff + DOS_PE_OFFSET), SEEK_SET) == -1)
  75     fatal ("Error seeking PE header");
  76
  77   if (fread (buff, PE_HEADER_LEN, 1, dll_file) != 1 ||
  78       get_int (buff) != PE_MAGIC)
  79     fatal ("Error reading PE header");
  80
  81   exports = get_int (buff + PE_EXPORTS_OFFSET);
  82   exports_len = get_int (buff + PE_EXPORTS_SIZE);
  83
  84   if (!exports || !exports_len)
  85     fatal ("No exports in DLL");
  86
  87   if (!(count = get_short (buff + PE_COUNT_OFFSET)))
  88     fatal ("No sections in DLL");
  89
  90   if (VERBOSE)
  91     printf ("DLL has %d sections\n", count);
  92
  93   /* Iterate through sections until we find exports */
  94   while (count--)
  95   {
  96     if (fread (buff, SECTION_HEADER_LEN, 1, dll_file) != 1)
  97       fatal ("Section read error");
  98
  99     code = get_int (buff + SECTION_ADDR_OFFSET);
 100     code_len = get_int (buff + SECTION_ADDR_SIZE);
 101
 102     if (code <= exports && code + code_len > exports)
 103       break;
 104   }
 105
 106   if (!count)
 107     fatal ("No export section");
 108
 109   code_len -= (exports - code);
 110
 111   if (code_len < exports_len)
 112     fatal ("Corrupt exports");
 113
 114   /* Load exports section */
 115   if (fseek (dll_file, get_int (buff + SECTION_POS_OFFSET)
 116          + exports - code, SEEK_SET) == -1)
 117     fatal ("Export section seek error");
 118
 119   if (VERBOSE)
 120     printf ("Export data size = %d bytes\n", code_len);
 121
 122   if (!(buff = (char *) realloc (buff, code_len)))
 123     fatal ("Out of memory");
 124
 125   if (fread (buff, code_len, 1, dll_file) != 1)
 126     fatal ("Read error");
 127
 128   dll_close();
 129
 130   /* Locate symbol names */
 131   symbol_data = REBASE( get_int (buff + EXPORT_NAME_OFFSET));
 132
 133   if (symbol_data > code_len)
 134     fatal ("Corrupt exports section");
 135
 136   if (!(dll_num_exports = get_int (buff + EXPORT_COUNT_OFFSET)))
 137     fatal ("No export count");
 138
 139   if (!(dll_symbols = (char **) malloc (dll_num_exports * sizeof (char *))))
 140     fatal ("Out of memory");
 141
 142   /* Read symbol names into 'dll_symbols' */
 143   count = 0;
 144   while (count <  dll_num_exports)
 145   {
 146     const int   symbol_offset = get_int (buff + symbol_data + count * 4);
 147     const char *symbol_name_ptr = REBASE (buff + symbol_offset);
 148
 149     assert(symbol_name_ptr);
 150     dll_symbols[count] = strdup (symbol_name_ptr);
 151     assert(dll_symbols[count]);
 152
 153     count++;
 154   }
 155
 156   if (NORMAL)
 157     printf ("%d exported symbols in DLL\n", dll_num_exports);
 158
 159   free (buff);
 160
 161   /* Set DLL output names */
 162   if ((buff = strrchr (globals.input_name, '/')))
 163     globals.input_name = buff + 1; /* Strip path */
 164
 165   OUTPUT_UC_DLL_NAME = str_toupper( strdup (OUTPUT_DLL_NAME));
 166 }
 167
 168
 169 /*******************************************************************
 170  *         dll_next_symbol
 171  *
 172  * Get next exported symbol from dll
 173  */
 174 char* dll_next_symbol ()
 175 {
 176   static unsigned int current_export = 0;
 177
 178   assert (current_export <= dll_num_exports);
 179
 180   if (current_export == dll_num_exports)
 181     return NULL;
 182
 183   assert (dll_symbols);
 184   assert (dll_symbols [current_export]);
 185
 186   return strdup (dll_symbols [current_export++]);
 187 }
 188
 189
 190 /*******************************************************************
 191  *         dll_close
 192  *
 193  * Free resources used by DLL
 194  */
 195 static void dll_close (void)
 196 {
 197   size_t i;
 198
 199   if (dll_file)
 200   {
 201     fclose (dll_file);
 202     dll_file = NULL;
 203   }
 204
 205   if (dll_symbols)
 206   {
 207     for (i = 0; i < dll_num_exports; i++)
 208       if (dll_symbols [i])
 209         free (dll_symbols [i]);
 210     free (dll_symbols);
 211     dll_symbols = NULL;
 212   }
 213 }