1/* This file is derived from the GAS 2.1.4 assembler control file. 2 The GAS product is under the GNU General Public License, version 2 or later. 3 As such, this file is also under that license. 4 5 If the file format changes in the COFF object, this file should be 6 subsequently updated to reflect the changes. 7 8 The actual loader module only uses a few of these structures. The full 9 set is documented here because I received the full set. If you wish 10 more information about COFF, then O'Reilly has a very excellent book. 11*/ 12 13#define E_SYMNMLEN 8 /* Number of characters in a symbol name */ 14#define E_FILNMLEN 14 /* Number of characters in a file name */ 15#define E_DIMNUM 4 /* Number of array dimensions in auxiliary entry */ 16 17/* 18 * These defines are byte order independent. There is no alignment of fields 19 * permitted in the structures. Therefore they are declared as characters 20 * and the values loaded from the character positions. It also makes it 21 * nice to have it "endian" independent. 22 */ 23 24/* Load a short int from the following tables with little-endian formats */ 25#define COFF_SHORT_L(ps) ((short)(((unsigned short)((unsigned char)ps[1])<<8)|\ 26 ((unsigned short)((unsigned char)ps[0])))) 27 28/* Load a long int from the following tables with little-endian formats */ 29#define COFF_LONG_L(ps) (((long)(((unsigned long)((unsigned char)ps[3])<<24) |\ 30 ((unsigned long)((unsigned char)ps[2])<<16) |\ 31 ((unsigned long)((unsigned char)ps[1])<<8) |\ 32 ((unsigned long)((unsigned char)ps[0]))))) 33 34/* Load a short int from the following tables with big-endian formats */ 35#define COFF_SHORT_H(ps) ((short)(((unsigned short)((unsigned char)ps[0])<<8)|\ 36 ((unsigned short)((unsigned char)ps[1])))) 37 38/* Load a long int from the following tables with big-endian formats */ 39#define COFF_LONG_H(ps) (((long)(((unsigned long)((unsigned char)ps[0])<<24) |\ 40 ((unsigned long)((unsigned char)ps[1])<<16) |\ 41 ((unsigned long)((unsigned char)ps[2])<<8) |\ 42 ((unsigned long)((unsigned char)ps[3]))))) 43 44/* These may be overridden later by brain dead implementations which generate 45 a big-endian header with little-endian data. In that case, generate a 46 replacement macro which tests a flag and uses either of the two above 47 as appropriate. */ 48 49#define COFF_LONG(v) COFF_LONG_L(v) 50#define COFF_SHORT(v) COFF_SHORT_L(v) 51 52/*** coff information for Intel 386/486. */ 53 54/********************** FILE HEADER **********************/ 55 56struct COFF_filehdr { 57 char f_magic[2]; /* magic number */ 58 char f_nscns[2]; /* number of sections */ 59 char f_timdat[4]; /* time & date stamp */ 60 char f_symptr[4]; /* file pointer to symtab */ 61 char f_nsyms[4]; /* number of symtab entries */ 62 char f_opthdr[2]; /* sizeof(optional hdr) */ 63 char f_flags[2]; /* flags */ 64}; 65 66/* 67 * Bits for f_flags: 68 * 69 * F_RELFLG relocation info stripped from file 70 * F_EXEC file is executable (i.e. no unresolved external 71 * references) 72 * F_LNNO line numbers stripped from file 73 * F_LSYMS local symbols stripped from file 74 * F_MINMAL this is a minimal object file (".m") output of fextract 75 * F_UPDATE this is a fully bound update file, output of ogen 76 * F_SWABD this file has had its bytes swabbed (in names) 77 * F_AR16WR this file has the byte ordering of an AR16WR 78 * (e.g. 11/70) machine 79 * F_AR32WR this file has the byte ordering of an AR32WR machine 80 * (e.g. vax and iNTEL 386) 81 * F_AR32W this file has the byte ordering of an AR32W machine 82 * (e.g. 3b,maxi) 83 * F_PATCH file contains "patch" list in optional header 84 * F_NODF (minimal file only) no decision functions for 85 * replaced functions 86 */ 87 88#define COFF_F_RELFLG 0000001 89#define COFF_F_EXEC 0000002 90#define COFF_F_LNNO 0000004 91#define COFF_F_LSYMS 0000010 92#define COFF_F_MINMAL 0000020 93#define COFF_F_UPDATE 0000040 94#define COFF_F_SWABD 0000100 95#define COFF_F_AR16WR 0000200 96#define COFF_F_AR32WR 0000400 97#define COFF_F_AR32W 0001000 98#define COFF_F_PATCH 0002000 99#define COFF_F_NODF 0002000 100 101#define COFF_I386MAGIC 0x14c /* Linux's system */ 102 103#define COFF_I386BADMAG(x) (COFF_SHORT((x).f_magic) != COFF_I386MAGIC) 104 105#define COFF_FILHDR struct COFF_filehdr 106#define COFF_FILHSZ sizeof(COFF_FILHDR) 107 108/********************** AOUT "OPTIONAL HEADER" **********************/ 109 110/* Linux COFF must have this "optional" header. Standard COFF has no entry 111 location for the "entry" point. They normally would start with the first 112 location of the .text section. This is not a good idea for linux. So, 113 the use of this "optional" header is not optional. It is required. 114 115 Do not be tempted to assume that the size of the optional header is 116 a constant and simply index the next byte by the size of this structure. 117 Use the 'f_opthdr' field in the main coff header for the size of the 118 structure actually written to the file!! 119*/ 120 121typedef struct 122{ 123 char magic[2]; /* type of file */ 124 char vstamp[2]; /* version stamp */ 125 char tsize[4]; /* text size in bytes, padded to FW bdry */ 126 char dsize[4]; /* initialized data " " */ 127 char bsize[4]; /* uninitialized data " " */ 128 char entry[4]; /* entry pt. */ 129 char text_start[4]; /* base of text used for this file */ 130 char data_start[4]; /* base of data used for this file */ 131} 132COFF_AOUTHDR; 133 134#define COFF_AOUTSZ (sizeof(COFF_AOUTHDR)) 135 136#define COFF_STMAGIC 0401 137#define COFF_OMAGIC 0404 138#define COFF_JMAGIC 0407 /* dirty text and data image, can't share */ 139#define COFF_DMAGIC 0410 /* dirty text segment, data aligned */ 140#define COFF_ZMAGIC 0413 /* The proper magic number for executables */ 141#define COFF_SHMAGIC 0443 /* shared library header */ 142 143/********************** SECTION HEADER **********************/ 144 145struct COFF_scnhdr { 146 char s_name[8]; /* section name */ 147 char s_paddr[4]; /* physical address, aliased s_nlib */ 148 char s_vaddr[4]; /* virtual address */ 149 char s_size[4]; /* section size */ 150 char s_scnptr[4]; /* file ptr to raw data for section */ 151 char s_relptr[4]; /* file ptr to relocation */ 152 char s_lnnoptr[4]; /* file ptr to line numbers */ 153 char s_nreloc[2]; /* number of relocation entries */ 154 char s_nlnno[2]; /* number of line number entries */ 155 char s_flags[4]; /* flags */ 156}; 157 158#define COFF_SCNHDR struct COFF_scnhdr 159#define COFF_SCNHSZ sizeof(COFF_SCNHDR) 160 161/* 162 * names of "special" sections 163 */ 164 165#define COFF_TEXT ".text" 166#define COFF_DATA ".data" 167#define COFF_BSS ".bss" 168#define COFF_COMMENT ".comment" 169#define COFF_LIB ".lib" 170 171#define COFF_SECT_TEXT 0 /* Section for instruction code */ 172#define COFF_SECT_DATA 1 /* Section for initialized globals */ 173#define COFF_SECT_BSS 2 /* Section for un-initialized globals */ 174#define COFF_SECT_REQD 3 /* Minimum number of sections for good file */ 175 176#define COFF_STYP_REG 0x00 /* regular segment */ 177#define COFF_STYP_DSECT 0x01 /* dummy segment */ 178#define COFF_STYP_NOLOAD 0x02 /* no-load segment */ 179#define COFF_STYP_GROUP 0x04 /* group segment */ 180#define COFF_STYP_PAD 0x08 /* .pad segment */ 181#define COFF_STYP_COPY 0x10 /* copy section */ 182#define COFF_STYP_TEXT 0x20 /* .text segment */ 183#define COFF_STYP_DATA 0x40 /* .data segment */ 184#define COFF_STYP_BSS 0x80 /* .bss segment */ 185#define COFF_STYP_INFO 0x200 /* .comment section */ 186#define COFF_STYP_OVER 0x400 /* overlay section */ 187#define COFF_STYP_LIB 0x800 /* library section */ 188 189/* 190 * Shared libraries have the following section header in the data field for 191 * each library. 192 */ 193 194struct COFF_slib { 195 char sl_entsz[4]; /* Size of this entry */ 196 char sl_pathndx[4]; /* size of the header field */ 197}; 198 199#define COFF_SLIBHD struct COFF_slib 200#define COFF_SLIBSZ sizeof(COFF_SLIBHD) 201 202/********************** LINE NUMBERS **********************/ 203 204/* 1 line number entry for every "breakpointable" source line in a section. 205 * Line numbers are grouped on a per function basis; first entry in a function 206 * grouping will have l_lnno = 0 and in place of physical address will be the 207 * symbol table index of the function name. 208 */ 209 210struct COFF_lineno { 211 union { 212 char l_symndx[4]; /* function name symbol index, iff l_lnno == 0*/ 213 char l_paddr[4]; /* (physical) address of line number */ 214 } l_addr; 215 char l_lnno[2]; /* line number */ 216}; 217 218#define COFF_LINENO struct COFF_lineno 219#define COFF_LINESZ 6 220 221/********************** SYMBOLS **********************/ 222 223#define COFF_E_SYMNMLEN 8 /* # characters in a short symbol name */ 224#define COFF_E_FILNMLEN 14 /* # characters in a file name */ 225#define COFF_E_DIMNUM 4 /* # array dimensions in auxiliary entry */ 226 227/* 228 * All symbols and sections have the following definition 229 */ 230 231struct COFF_syment 232{ 233 union { 234 char e_name[E_SYMNMLEN]; /* Symbol name (first 8 characters) */ 235 struct { 236 char e_zeroes[4]; /* Leading zeros */ 237 char e_offset[4]; /* Offset if this is a header section */ 238 } e; 239 } e; 240 241 char e_value[4]; /* Value (address) of the segment */ 242 char e_scnum[2]; /* Section number */ 243 char e_type[2]; /* Type of section */ 244 char e_sclass[1]; /* Loader class */ 245 char e_numaux[1]; /* Number of auxiliary entries which follow */ 246}; 247 248#define COFF_N_BTMASK (0xf) /* Mask for important class bits */ 249#define COFF_N_TMASK (0x30) /* Mask for important type bits */ 250#define COFF_N_BTSHFT (4) /* # bits to shift class field */ 251#define COFF_N_TSHIFT (2) /* # bits to shift type field */ 252 253/* 254 * Auxiliary entries because the main table is too limiting. 255 */ 256 257union COFF_auxent { 258 259/* 260 * Debugger information 261 */ 262 263 struct { 264 char x_tagndx[4]; /* str, un, or enum tag indx */ 265 union { 266 struct { 267 char x_lnno[2]; /* declaration line number */ 268 char x_size[2]; /* str/union/array size */ 269 } x_lnsz; 270 char x_fsize[4]; /* size of function */ 271 } x_misc; 272 273 union { 274 struct { /* if ISFCN, tag, or .bb */ 275 char x_lnnoptr[4]; /* ptr to fcn line # */ 276 char x_endndx[4]; /* entry ndx past block end */ 277 } x_fcn; 278 279 struct { /* if ISARY, up to 4 dimen. */ 280 char x_dimen[E_DIMNUM][2]; 281 } x_ary; 282 } x_fcnary; 283 284 char x_tvndx[2]; /* tv index */ 285 } x_sym; 286 287/* 288 * Source file names (debugger information) 289 */ 290 291 union { 292 char x_fname[E_FILNMLEN]; 293 struct { 294 char x_zeroes[4]; 295 char x_offset[4]; 296 } x_n; 297 } x_file; 298 299/* 300 * Section information 301 */ 302 303 struct { 304 char x_scnlen[4]; /* section length */ 305 char x_nreloc[2]; /* # relocation entries */ 306 char x_nlinno[2]; /* # line numbers */ 307 } x_scn; 308 309/* 310 * Transfer vector (branch table) 311 */ 312 313 struct { 314 char x_tvfill[4]; /* tv fill value */ 315 char x_tvlen[2]; /* length of .tv */ 316 char x_tvran[2][2]; /* tv range */ 317 } x_tv; /* info about .tv section (in auxent of symbol .tv)) */ 318}; 319 320#define COFF_SYMENT struct COFF_syment 321#define COFF_SYMESZ 18 322#define COFF_AUXENT union COFF_auxent 323#define COFF_AUXESZ 18 324 325#define COFF_ETEXT "etext" 326 327/********************** RELOCATION DIRECTIVES **********************/ 328 329struct COFF_reloc { 330 char r_vaddr[4]; /* Virtual address of item */ 331 char r_symndx[4]; /* Symbol index in the symtab */ 332 char r_type[2]; /* Relocation type */ 333}; 334 335#define COFF_RELOC struct COFF_reloc 336#define COFF_RELSZ 10 337 338#define COFF_DEF_DATA_SECTION_ALIGNMENT 4 339#define COFF_DEF_BSS_SECTION_ALIGNMENT 4 340#define COFF_DEF_TEXT_SECTION_ALIGNMENT 4 341 342/* For new sections we haven't heard of before */ 343#define COFF_DEF_SECTION_ALIGNMENT 4 344