1 /* Yet Another Try at encapsulating bfd object files in coff. 2 Copyright (C) 1988-2014 Free Software Foundation, Inc. 3 Written by Pace Willisson 12/9/88 4 5 This file is obsolete. It needs to be converted to just define a bunch 6 of stuff that BFD can use to do coff-encapsulated files. --gnu (at) cygnus.com 7 8 This program is free software; you can redistribute it and/or modify 9 it under the terms of the GNU General Public License as published by 10 the Free Software Foundation; either version 3 of the License, or 11 (at your option) any later version. 12 13 This program is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with this program; if not, write to the Free Software 20 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, 21 MA 02110-1301, USA. */ 22 23 /* 24 * We only use the coff headers to tell the kernel 25 * how to exec the file. Therefore, the only fields that need to 26 * be filled in are the scnptr and vaddr for the text and data 27 * sections, and the vaddr for the bss. As far as coff is concerned, 28 * there is no symbol table, relocation, or line numbers. 29 * 30 * A normal bsd header (struct exec) is placed after the coff headers, 31 * and before the real text. I defined a the new fields 'a_machtype' 32 * and a_flags. If a_machtype is M_386, and a_flags & A_ENCAP is 33 * true, then the bsd header is preceeded by a coff header. Macros 34 * like N_TXTOFF and N_TXTADDR use this field to find the bsd header. 35 * 36 * The only problem is to track down the bsd exec header. The 37 * macros HEADER_OFFSET, etc do this. 38 */ 39 40 #define N_FLAGS_COFF_ENCAPSULATE 0x20 /* coff header precedes bsd header */ 41 42 /* Describe the COFF header used for encapsulation. */ 43 44 struct coffheader 45 { 46 /* filehdr */ 47 unsigned short f_magic; 48 unsigned short f_nscns; 49 long f_timdat; 50 long f_symptr; 51 long f_nsyms; 52 unsigned short f_opthdr; 53 unsigned short f_flags; 54 /* aouthdr */ 55 short magic; 56 short vstamp; 57 long tsize; 58 long dsize; 59 long bsize; 60 long entry; 61 long text_start; 62 long data_start; 63 struct coffscn 64 { 65 char s_name[8]; 66 long s_paddr; 67 long s_vaddr; 68 long s_size; 69 long s_scnptr; 70 long s_relptr; 71 long s_lnnoptr; 72 unsigned short s_nreloc; 73 unsigned short s_nlnno; 74 long s_flags; 75 } scns[3]; 76 }; 77 78 /* Describe some of the parameters of the encapsulation, 80 including how to find the encapsulated BSD header. */ 81 82 /* FIXME, this is dumb. The same tools can't handle a.outs for different 83 architectures, just because COFF_MAGIC is different; so you need a 84 separate GNU nm for every architecture!!? Unfortunately, it needs to 85 be this way, since the COFF_MAGIC value is determined by the kernel 86 we're trying to fool here. */ 87 88 #define COFF_MAGIC_I386 0514 /* I386MAGIC */ 89 #define COFF_MAGIC_M68K 0520 /* MC68MAGIC */ 90 91 #ifdef COFF_MAGIC 92 short __header_offset_temp; 93 #define HEADER_OFFSET(f) \ 94 (__header_offset_temp = 0, \ 95 fread ((char *)&__header_offset_temp, sizeof (short), 1, (f)), \ 96 fseek ((f), -sizeof (short), 1), \ 97 __header_offset_temp==COFF_MAGIC ? sizeof(struct coffheader) : 0) 98 #else 99 #define HEADER_OFFSET(f) 0 100 #endif 101 102 #define HEADER_SEEK(f) (fseek ((f), HEADER_OFFSET((f)), 1)) 103 104 /* Describe the characteristics of the BSD header 106 that appears inside the encapsulation. */ 107 108 /* Encapsulated coff files that are linked ZMAGIC have a text segment 109 offset just past the header (and a matching TXTADDR), excluding 110 the headers from the text segment proper but keeping the physical 111 layout and the virtual memory layout page-aligned. 112 113 Non-encapsulated a.out files that are linked ZMAGIC have a text 114 segment that starts at 0 and an N_TXTADR similarly offset to 0. 115 They too are page-aligned with each other, but they include the 116 a.out header as part of the text. 117 118 The _N_HDROFF gets sizeof struct exec added to it, so we have 119 to compensate here. See <a.out.gnu.h>. */ 120 121 #undef _N_HDROFF 122 #undef N_TXTADDR 123 #undef N_DATADDR 124 125 #define _N_HDROFF(x) ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \ 126 sizeof (struct coffheader) : 0) 127 128 /* Address of text segment in memory after it is loaded. */ 129 #define N_TXTADDR(x) \ 130 ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \ 131 sizeof (struct coffheader) + sizeof (struct exec) : 0) 132 #define SEGMENT_SIZE 0x400000 133 134 #define N_DATADDR(x) \ 135 ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \ 136 (SEGMENT_SIZE + ((N_TXTADDR(x)+(x).a_text-1) & ~(SEGMENT_SIZE-1))) : \ 137 (N_TXTADDR(x)+(x).a_text)) 138
