mdw@git.distorted.org.uk Git - ssr/blob - StraySrc/SDLS/cdll/c/decode

   1 /*
   2  * decode.c
   3  *
   4  * Find all the symbols in an ALF or AOF file.
   5  *
   6  * © 1994-1998 Straylight
   7  */
   8
   9 /*----- Licensing note ----------------------------------------------------*
  10  *
  11  * This file is part of Straylight's Dynamic Linking System (SDLS)
  12  *
  13  * SDLS is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2, or (at your option)
  16  * any later version.
  17  *
  18  * SDLS is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with SDLS.  If not, write to the Free Software Foundation,
  25  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  26  */
  27
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31
  32 #include "decode.h"
  33 #include "aof/chunk.h"
  34 #include "aof/aof.h"
  35 #include "aof/alf.h"
  36 #include "error.h"
  37
  38 static int decode__findChunk(chunk_header *c,char *name)
  39 {
  40   int i;
  41   for (i=0;i<c->hdr.maxChunks;i++)
  42   {
  43     if (c->table[i].offset && !memcmp(c->table[i].chunkName,name,8))
  44       return (i);
  45   }
  46   return (-1);
  47 }
  48
  49 static int decode__listALF(chunk_header *c,
  50                            hashtable h,
  51                            FILE *fp,
  52                            char *name,
  53                            int entry)
  54 {
  55   int size=c->table[entry].size;        /* Help the compiler a bit      */
  56   char *data=malloc(size);              /* Allocate memory for chunk    */
  57
  58   name=name;
  59
  60   {
  61     if (!data)
  62       error(NOMEM);
  63   }
  64
  65   {
  66     /* --- Note to the squeamish --- *
  67      *
  68      * I've done naughty things with fpos_t here to avoid reading the file
  69      * sequentially.  This file isn't doing anything particularly portable
  70      * anyway, so this is no great hardship.
  71      */
  72
  73     fpos_t off;                         /* To set file position         */
  74     off.__lo=c->table[entry].offset;    /* Widge the position indicator */
  75     fsetpos(fp,&off);                   /* Set the file offset nicely   */
  76     fread(data,1,size,fp);              /* Read external names table    */
  77   }
  78
  79   {
  80     int i=0;                            /* Counter through data         */
  81     alf_symTable *tbl;                  /* Pointer to actual structures */
  82     while (i<size)                      /* Continue until no more       */
  83     {
  84       tbl=(alf_symTable *)(data+i);     /* Set up the pointer           */
  85       if (!hash_add(h,tbl->data))       /* Try to add the symbol name   */
  86         error(NOMEM);
  87       i+=tbl->entryLength;              /* Bump the index along a bit   */
  88     }
  89   }
  90
  91   {
  92     free(data);
  93   }
  94
  95   return (0);
  96 }
  97
  98 static int decode__listAOF(chunk_header *c,
  99                            hashtable h,
 100                            FILE *fp,
 101                            char *name,
 102                            int sym,
 103                            int str)
 104
 105 {
 106   int sizeSym=c->table[sym].size;       /* Help the compiler a bit      */
 107   int sizeStr=c->table[str].size;       /* Help the compiler a bit      */
 108   aof_symbol *symbol=malloc(sizeSym);   /* Memory for symbol table      */
 109   char *string=malloc(sizeStr);         /* Memory for string table      */
 110   int symbols;                          /* Number of symbol entries     */
 111   int headoff=0;                        /* Offset to AOF header chunk   */
 112   int err=0;                            /* No errors yet                */
 113
 114   /* --- Check we got the memory --- */
 115
 116   {
 117     if (!symbol || !string)
 118       error(NOMEM);
 119   }
 120
 121   if (!err)
 122   {
 123     if (headoff=decode__findChunk(c,"OBJ_HEAD"),headoff==-1)
 124     {
 125       error(BADFILE,name);
 126       err=1;
 127     }
 128   }
 129
 130   if (!err)
 131   {
 132     /* --- Note to the squeamish --- *
 133      *
 134      * I've done naughty things with fpos_t here to avoid reading the file
 135      * sequentially.  This file isn't doing anything particularly portable
 136      * anyway, so this is no great hardship.
 137      */
 138
 139     fpos_t off;                         /* To set file position         */
 140
 141     off.__lo=c->table[headoff].offset+12l; /* Find number of symbols    */
 142     fsetpos(fp,&off);                   /* Set the file offset nicely   */
 143     fread(&symbols,sizeof(symbols),1,fp); /* Read symbol count          */
 144     off.__lo=c->table[sym].offset;      /* Widge the position indicator */
 145     fsetpos(fp,&off);                   /* Set the file offset nicely   */
 146     fread(symbol,1,sizeSym,fp);         /* Read symbol table            */
 147     off.__lo=c->table[str].offset;      /* Widge the position indicator */
 148     fsetpos(fp,&off);                   /* Set the file offset nicely   */
 149     fread(string,1,sizeStr,fp);         /* Read string table            */
 150   }
 151
 152   if (!err)
 153   {
 154     int i;                              /* Counter through data         */
 155     for (i=0;i<symbols;i++)
 156     {
 157       if (symbol[i].defined && symbol[i].export)
 158       {
 159         if (!hash_add(h,string+symbol[i].name))
 160           error(NOMEM);
 161       }
 162     }
 163   }
 164
 165   {
 166     free(string);
 167     free(symbol);
 168   }
 169
 170   return (err);
 171 }
 172
 173 int decode(hashtable h,char *filename)
 174 {
 175   chunk_header *chf=0;                  /* Ptr to block to read table   */
 176   FILE *fp=fopen(filename,"rb");        /* Open for binary reading      */
 177   int err=0;                            /* No errors yet                */
 178
 179   {
 180     chunk_fixedHeader ch={0,0,0};       /* For reading in the header    */
 181
 182     if (!fp)                            /* If open failed,...           */
 183     {
 184       error(NOOPENIN,filename);         /* Report an error, and         */
 185       err=1;                            /*   return gracefully          */
 186     }
 187     else
 188     {
 189       fread(&ch,sizeof(ch),1,fp);       /* Read the file's header       */
 190       if (ch.id!=chunk_MAGIC)           /* Check it's a real chunk file */
 191       {
 192         error(BADFILE,filename);
 193         err=1;
 194       }
 195       else
 196       {
 197         chf=malloc(sizeof(chunk_fixedHeader)+
 198                    ch.maxChunks*sizeof(chunk_tableEntry));
 199         if (!chf)                       /* If allocation failed         */
 200           error(NOMEM);
 201         chf->hdr=ch;
 202         fread(chf->table,sizeof(chunk_tableEntry),ch.maxChunks,fp);
 203       }
 204     }
 205   }
 206
 207   if (!err)
 208   {
 209     int index;                          /* Index of symbol table chunk  */
 210     int string;                         /* Index of string table chunk  */
 211
 212     if (index=decode__findChunk(chf,"OFL_SYMT"),index!=-1)
 213       decode__listALF(chf,h,fp,filename,index);
 214     else if ( (index=decode__findChunk(chf,"OBJ_SYMT"),index!=-1) &&
 215               (string=decode__findChunk(chf,"OBJ_STRT"),string!=-1))
 216       decode__listAOF(chf,h,fp,filename,index,string);
 217     else
 218     {
 219       error(BADFILE,filename);
 220       err=1;
 221     }
 222   }
 223
 224   {
 225     if (fp)
 226       fclose(fp);                       /* Don't need this any more     */
 227     free(chf);                          /* Get rid of that too          */
 228   }
 229
 230   return (err);
 231 }