mirror of https://github.com/Cisco-Talos/clamav
Tomasz Kojm
22 years ago
parent
20c3d44d09
commit
5f1a932bf4
@ -0,0 +1,190 @@ |
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/*
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* Copyright (C) 2004 aCaB <acab@clamav.net> |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program; if not, write to the Free Software |
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
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*/ |
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|
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/*
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** defsg.c |
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**
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** 02/08/2k4 - Dumped and reversed |
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** 02/08/2k4 - Done coding |
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** 03/08/2k4 - Cleaning and securing |
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** 04/08/2k4 - Done porting |
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*/ |
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/*
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** Unpacks an FSG compressed section. |
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** |
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** Czesc bart, good asm, nice piece of code ;) |
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*/ |
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#if HAVE_CONFIG_H |
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#include "clamav-config.h" |
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#endif |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <sys/types.h> |
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#include <sys/stat.h> |
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#include <unistd.h> |
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#include <string.h> |
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#include "cltypes.h" |
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#include "pe.h" |
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#include "rebuildpe.h" |
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#include "others.h" |
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static int doubledl(char **scur, uint8_t *mydlptr, char *buffer, int buffersize) |
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{ |
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unsigned char mydl = *mydlptr; |
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unsigned char olddl = mydl; |
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mydl*=2; |
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if ( !(olddl & 0x7f)) { |
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if ( *scur < buffer || *scur >= buffer+buffersize-1 ) |
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return -1; |
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olddl = **scur; |
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mydl = olddl*2+1; |
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*scur=*scur + 1; |
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} |
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*mydlptr = mydl; |
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return (olddl>>7)&1; |
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} |
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int unfsg(char *source, char *dest, int ssize, int dsize) { |
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uint8_t mydl=0x80; |
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uint32_t backbytes, backsize, oldback; |
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char *csrc = source, *cdst = dest; |
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int oob, lostbit = 1; |
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/* I assume buffers size is >0 - No checking! */ |
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*cdst++=*csrc++; |
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while ( 1 ) { |
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if ((oob=doubledl(&csrc, &mydl, source, ssize))) { |
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if (oob == -1) |
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return -1; |
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/* 164 */ |
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backsize = 0; |
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if ((oob=doubledl(&csrc, &mydl, source, ssize))) { |
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if (oob == -1) |
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return -1; |
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/* 16a */ |
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backbytes = 0; |
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if ((oob=doubledl(&csrc, &mydl, source, ssize))) { |
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if (oob == -1) |
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return -1; |
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/* 170 */ |
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lostbit = 1; |
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backsize++; |
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backbytes = 0x10; |
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while ( backbytes < 0x100 ) { |
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1) |
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return -1; |
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backbytes = backbytes*2+oob; |
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} |
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backbytes &= 0xff; |
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if ( ! backbytes ) { |
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if (cdst >= dest+dsize) |
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return -1; |
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*cdst++=0x00; |
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continue; |
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} else { |
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/* repne movsb - FIXME dont remove for now */ |
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} |
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} else { |
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/* 18f */ |
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if (csrc >= source+ssize) |
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return -1; |
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backbytes = *(unsigned char*)csrc; |
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backsize = backsize * 2 + (backbytes & 1); |
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backbytes = (backbytes & 0xff)>>1; |
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csrc++; |
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if (! backbytes) |
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break; |
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backsize+=2; |
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oldback = backbytes; |
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lostbit = 0; |
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} |
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} else { |
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/* 180 */ |
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backsize = 1; |
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do { |
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1) |
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return -1; |
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backsize = backsize*2+oob; |
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1) |
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return -1; |
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} while (oob); |
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backsize = backsize - 1 - lostbit; |
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if (! backsize) { |
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/* 18a */ |
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backsize = 1; |
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do { |
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1) |
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return -1; |
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backsize = backsize*2+oob; |
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1) |
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return -1; |
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} while (oob); |
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backbytes = oldback; |
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} else { |
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/* 198 */ |
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if (csrc >= source+ssize) |
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return -1; |
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backbytes = *(unsigned char*)csrc; |
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backbytes += (backsize-1)<<8; |
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backsize = 1; |
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csrc++; |
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do { |
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1) |
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return -1; |
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backsize = backsize*2+oob; |
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1) |
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return -1; |
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} while (oob); |
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if (backbytes >= 0x7d00) |
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backsize++; |
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if (backbytes >= 0x500) |
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backsize++; |
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if (backbytes <= 0x7f) |
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backsize += 2; |
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oldback = backbytes; |
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} |
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lostbit = 0; |
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} |
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if (cdst-backbytes < dest || cdst+backsize >= dest+dsize) |
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return -1; |
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while(backsize--) { |
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*cdst=*(cdst-backbytes); |
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cdst++; |
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} |
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} else { |
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/* 15d */ |
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if (cdst < dest || cdst >= dest+dsize || csrc < source || csrc >= source+ssize) |
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return -1; |
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*cdst++=*csrc++; |
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lostbit=1; |
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} |
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} |
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return 0; |
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} |
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@ -0,0 +1,28 @@ |
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/*
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* Copyright (C) 2004 aCaB <acab@clamav.net> |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program; if not, write to the Free Software |
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
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*/ |
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|
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#ifndef __FSG_H |
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#define __FSG_H |
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#include "cltypes.h" |
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#include "pe.h" |
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int unfsg(char *, char *, int, int); |
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#endif |
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