1 /* Yet Another Try at encapsulating bsd object files in coff. 2 Copyright 1988, 1989, 1991 Free Software Foundation, Inc. 3 Written by Pace Willisson 12/9/88 4 5 This file is obsolete.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@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 2 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, MA 02110-1301, USA. */ 21 22 /* 23 * We only use the coff headers to tell the kernel 24 * how to exec the file. Therefore, the only fields that need to 25 * be filled in are the scnptr and vaddr for the text and data 26 * sections, and the vaddr for the bss. As far as coff is concerned, 27 * there is no symbol table, relocation, or line numbers. 28 * 29 * A normal bsd header (struct exec) is placed after the coff headers, 30 * and before the real text. I defined a the new fields 'a_machtype' 31 * and a_flags. If a_machtype is M_386, and a_flags & A_ENCAP is 32 * true, then the bsd header is preceeded by a coff header. Macros 33 * like N_TXTOFF and N_TXTADDR use this field to find the bsd header. 34 * 35 * The only problem is to track down the bsd exec header. The 36 * macros HEADER_OFFSET, etc do this. 37 */ 38 39 #define N_FLAGS_COFF_ENCAPSULATE 0x20 /* coff header precedes bsd header */ 40 41 /* Describe the COFF header used for encapsulation. */ 42 43 struct coffheader 44 { 45 /* filehdr */ 46 unsigned short f_magic; 47 unsigned short f_nscns; 48 long f_timdat; 49 long f_symptr; 50 long f_nsyms; 51 unsigned short f_opthdr; 52 unsigned short f_flags; 53 /* aouthdr */ 54 short magic; 55 short vstamp; 56 long tsize; 57 long dsize; 58 long bsize; 59 long entry; 60 long text_start; 61 long data_start; 62 struct coffscn 63 { 64 char s_name[8]; 65 long s_paddr; 66 long s_vaddr; 67 long s_size; 68 long s_scnptr; 69 long s_relptr; 70 long s_lnnoptr; 71 unsigned short s_nreloc; 72 unsigned short s_nlnno; 73 long s_flags; 74 } scns[3]; 75 }; 76 77 /* Describe some of the parameters of the encapsulation, 78 including how to find the encapsulated BSD header. */ 79 80 /* FIXME, this is dumb. The same tools can't handle a.outs for different 81 architectures, just because COFF_MAGIC is different; so you need a 82 separate GNU nm for every architecture!!? Unfortunately, it needs to 83 be this way, since the COFF_MAGIC value is determined by the kernel 84 we're trying to fool here. */ 85 86 #define COFF_MAGIC_I386 0514 /* I386MAGIC */ 87 #define COFF_MAGIC_M68K 0520 /* MC68MAGIC */ 88 89 #ifdef COFF_MAGIC 90 short __header_offset_temp; 91 #define HEADER_OFFSET(f) \ 92 (__header_offset_temp = 0, \ 93 fread ((char *)&__header_offset_temp, sizeof (short), 1, (f)), \ 94 fseek ((f), -sizeof (short), 1), \ 95 __header_offset_temp==COFF_MAGIC ? sizeof(struct coffheader) : 0) 96 #else 97 #define HEADER_OFFSET(f) 0 98 #endif 99 100 #define HEADER_SEEK(f) (fseek ((f), HEADER_OFFSET((f)), 1)) 101 102 /* Describe the characteristics of the BSD header 103 that appears inside the encapsulation. */ 104 105 /* Encapsulated coff files that are linked ZMAGIC have a text segment 106 offset just past the header (and a matching TXTADDR), excluding 107 the headers from the text segment proper but keeping the physical 108 layout and the virtual memory layout page-aligned. 109 110 Non-encapsulated a.out files that are linked ZMAGIC have a text 111 segment that starts at 0 and an N_TXTADR similarly offset to 0. 112 They too are page-aligned with each other, but they include the 113 a.out header as part of the text. 114 115 The _N_HDROFF gets sizeof struct exec added to it, so we have 116 to compensate here. See <a.out.gnu.h>. */ 117 118 #undef _N_HDROFF 119 #undef N_TXTADDR 120 #undef N_DATADDR 121 122 #define _N_HDROFF(x) ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \ 123 sizeof (struct coffheader) : 0) 124 125 /* Address of text segment in memory after it is loaded. */ 126 #define N_TXTADDR(x) \ 127 ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \ 128 sizeof (struct coffheader) + sizeof (struct exec) : 0) 129 #define SEGMENT_SIZE 0x400000 130 131 #define N_DATADDR(x) \ 132 ((N_FLAGS(x) & N_FLAGS_COFF_ENCAPSULATE) ? \ 133 (SEGMENT_SIZE + ((N_TXTADDR(x)+(x).a_text-1) & ~(SEGMENT_SIZE-1))) : \ 134 (N_TXTADDR(x)+(x).a_text)) 135