Colin Cross | 7bb052a | 2015-02-03 12:59:37 -0800 | [diff] [blame^] | 1 | // Copyright 2009 The Go Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | // Mach-O file writing |
| 6 | // http://developer.apple.com/mac/library/DOCUMENTATION/DeveloperTools/Conceptual/MachORuntime/Reference/reference.html |
| 7 | |
| 8 | #include "l.h" |
| 9 | #include "../ld/dwarf.h" |
| 10 | #include "../ld/lib.h" |
| 11 | #include "../ld/macho.h" |
| 12 | |
| 13 | static int macho64; |
| 14 | static MachoHdr hdr; |
| 15 | static MachoLoad *load; |
| 16 | static MachoSeg seg[16]; |
| 17 | static int nload, mload, nseg, ndebug, nsect; |
| 18 | |
| 19 | enum |
| 20 | { |
| 21 | SymKindLocal = 0, |
| 22 | SymKindExtdef, |
| 23 | SymKindUndef, |
| 24 | NumSymKind |
| 25 | }; |
| 26 | |
| 27 | static int nkind[NumSymKind]; |
| 28 | static LSym** sortsym; |
| 29 | static int nsortsym; |
| 30 | |
| 31 | // Amount of space left for adding load commands |
| 32 | // that refer to dynamic libraries. Because these have |
| 33 | // to go in the Mach-O header, we can't just pick a |
| 34 | // "big enough" header size. The initial header is |
| 35 | // one page, the non-dynamic library stuff takes |
| 36 | // up about 1300 bytes; we overestimate that as 2k. |
| 37 | static int load_budget = INITIAL_MACHO_HEADR - 2*1024; |
| 38 | |
| 39 | static void machodysymtab(void); |
| 40 | |
| 41 | void |
| 42 | machoinit(void) |
| 43 | { |
| 44 | switch(thechar) { |
| 45 | // 64-bit architectures |
| 46 | case '6': |
| 47 | macho64 = 1; |
| 48 | break; |
| 49 | |
| 50 | // 32-bit architectures |
| 51 | default: |
| 52 | break; |
| 53 | } |
| 54 | } |
| 55 | |
| 56 | MachoHdr* |
| 57 | getMachoHdr(void) |
| 58 | { |
| 59 | return &hdr; |
| 60 | } |
| 61 | |
| 62 | MachoLoad* |
| 63 | newMachoLoad(uint32 type, uint32 ndata) |
| 64 | { |
| 65 | MachoLoad *l; |
| 66 | |
| 67 | if(nload >= mload) { |
| 68 | if(mload == 0) |
| 69 | mload = 1; |
| 70 | else |
| 71 | mload *= 2; |
| 72 | load = erealloc(load, mload*sizeof load[0]); |
| 73 | } |
| 74 | |
| 75 | if(macho64 && (ndata & 1)) |
| 76 | ndata++; |
| 77 | |
| 78 | l = &load[nload++]; |
| 79 | l->type = type; |
| 80 | l->ndata = ndata; |
| 81 | l->data = mal(ndata*4); |
| 82 | return l; |
| 83 | } |
| 84 | |
| 85 | MachoSeg* |
| 86 | newMachoSeg(char *name, int msect) |
| 87 | { |
| 88 | MachoSeg *s; |
| 89 | |
| 90 | if(nseg >= nelem(seg)) { |
| 91 | diag("too many segs"); |
| 92 | errorexit(); |
| 93 | } |
| 94 | s = &seg[nseg++]; |
| 95 | s->name = name; |
| 96 | s->msect = msect; |
| 97 | s->sect = mal(msect*sizeof s->sect[0]); |
| 98 | return s; |
| 99 | } |
| 100 | |
| 101 | MachoSect* |
| 102 | newMachoSect(MachoSeg *seg, char *name, char *segname) |
| 103 | { |
| 104 | MachoSect *s; |
| 105 | |
| 106 | if(seg->nsect >= seg->msect) { |
| 107 | diag("too many sects in segment %s", seg->name); |
| 108 | errorexit(); |
| 109 | } |
| 110 | s = &seg->sect[seg->nsect++]; |
| 111 | s->name = name; |
| 112 | s->segname = segname; |
| 113 | nsect++; |
| 114 | return s; |
| 115 | } |
| 116 | |
| 117 | // Generic linking code. |
| 118 | |
| 119 | static char **dylib; |
| 120 | static int ndylib; |
| 121 | |
| 122 | static vlong linkoff; |
| 123 | |
| 124 | int |
| 125 | machowrite(void) |
| 126 | { |
| 127 | vlong o1; |
| 128 | int loadsize; |
| 129 | int i, j; |
| 130 | MachoSeg *s; |
| 131 | MachoSect *t; |
| 132 | MachoLoad *l; |
| 133 | |
| 134 | o1 = cpos(); |
| 135 | |
| 136 | loadsize = 4*4*ndebug; |
| 137 | for(i=0; i<nload; i++) |
| 138 | loadsize += 4*(load[i].ndata+2); |
| 139 | if(macho64) { |
| 140 | loadsize += 18*4*nseg; |
| 141 | loadsize += 20*4*nsect; |
| 142 | } else { |
| 143 | loadsize += 14*4*nseg; |
| 144 | loadsize += 17*4*nsect; |
| 145 | } |
| 146 | |
| 147 | if(macho64) |
| 148 | LPUT(0xfeedfacf); |
| 149 | else |
| 150 | LPUT(0xfeedface); |
| 151 | LPUT(hdr.cpu); |
| 152 | LPUT(hdr.subcpu); |
| 153 | if(linkmode == LinkExternal) |
| 154 | LPUT(1); /* file type - mach object */ |
| 155 | else |
| 156 | LPUT(2); /* file type - mach executable */ |
| 157 | LPUT(nload+nseg+ndebug); |
| 158 | LPUT(loadsize); |
| 159 | LPUT(1); /* flags - no undefines */ |
| 160 | if(macho64) |
| 161 | LPUT(0); /* reserved */ |
| 162 | |
| 163 | for(i=0; i<nseg; i++) { |
| 164 | s = &seg[i]; |
| 165 | if(macho64) { |
| 166 | LPUT(25); /* segment 64 */ |
| 167 | LPUT(72+80*s->nsect); |
| 168 | strnput(s->name, 16); |
| 169 | VPUT(s->vaddr); |
| 170 | VPUT(s->vsize); |
| 171 | VPUT(s->fileoffset); |
| 172 | VPUT(s->filesize); |
| 173 | LPUT(s->prot1); |
| 174 | LPUT(s->prot2); |
| 175 | LPUT(s->nsect); |
| 176 | LPUT(s->flag); |
| 177 | } else { |
| 178 | LPUT(1); /* segment 32 */ |
| 179 | LPUT(56+68*s->nsect); |
| 180 | strnput(s->name, 16); |
| 181 | LPUT(s->vaddr); |
| 182 | LPUT(s->vsize); |
| 183 | LPUT(s->fileoffset); |
| 184 | LPUT(s->filesize); |
| 185 | LPUT(s->prot1); |
| 186 | LPUT(s->prot2); |
| 187 | LPUT(s->nsect); |
| 188 | LPUT(s->flag); |
| 189 | } |
| 190 | for(j=0; j<s->nsect; j++) { |
| 191 | t = &s->sect[j]; |
| 192 | if(macho64) { |
| 193 | strnput(t->name, 16); |
| 194 | strnput(t->segname, 16); |
| 195 | VPUT(t->addr); |
| 196 | VPUT(t->size); |
| 197 | LPUT(t->off); |
| 198 | LPUT(t->align); |
| 199 | LPUT(t->reloc); |
| 200 | LPUT(t->nreloc); |
| 201 | LPUT(t->flag); |
| 202 | LPUT(t->res1); /* reserved */ |
| 203 | LPUT(t->res2); /* reserved */ |
| 204 | LPUT(0); /* reserved */ |
| 205 | } else { |
| 206 | strnput(t->name, 16); |
| 207 | strnput(t->segname, 16); |
| 208 | LPUT(t->addr); |
| 209 | LPUT(t->size); |
| 210 | LPUT(t->off); |
| 211 | LPUT(t->align); |
| 212 | LPUT(t->reloc); |
| 213 | LPUT(t->nreloc); |
| 214 | LPUT(t->flag); |
| 215 | LPUT(t->res1); /* reserved */ |
| 216 | LPUT(t->res2); /* reserved */ |
| 217 | } |
| 218 | } |
| 219 | } |
| 220 | |
| 221 | for(i=0; i<nload; i++) { |
| 222 | l = &load[i]; |
| 223 | LPUT(l->type); |
| 224 | LPUT(4*(l->ndata+2)); |
| 225 | for(j=0; j<l->ndata; j++) |
| 226 | LPUT(l->data[j]); |
| 227 | } |
| 228 | |
| 229 | return cpos() - o1; |
| 230 | } |
| 231 | |
| 232 | void |
| 233 | domacho(void) |
| 234 | { |
| 235 | LSym *s; |
| 236 | |
| 237 | if(debug['d']) |
| 238 | return; |
| 239 | |
| 240 | // empirically, string table must begin with " \x00". |
| 241 | s = linklookup(ctxt, ".machosymstr", 0); |
| 242 | s->type = SMACHOSYMSTR; |
| 243 | s->reachable = 1; |
| 244 | adduint8(ctxt, s, ' '); |
| 245 | adduint8(ctxt, s, '\0'); |
| 246 | |
| 247 | s = linklookup(ctxt, ".machosymtab", 0); |
| 248 | s->type = SMACHOSYMTAB; |
| 249 | s->reachable = 1; |
| 250 | |
| 251 | if(linkmode != LinkExternal) { |
| 252 | s = linklookup(ctxt, ".plt", 0); // will be __symbol_stub |
| 253 | s->type = SMACHOPLT; |
| 254 | s->reachable = 1; |
| 255 | |
| 256 | s = linklookup(ctxt, ".got", 0); // will be __nl_symbol_ptr |
| 257 | s->type = SMACHOGOT; |
| 258 | s->reachable = 1; |
| 259 | s->align = 4; |
| 260 | |
| 261 | s = linklookup(ctxt, ".linkedit.plt", 0); // indirect table for .plt |
| 262 | s->type = SMACHOINDIRECTPLT; |
| 263 | s->reachable = 1; |
| 264 | |
| 265 | s = linklookup(ctxt, ".linkedit.got", 0); // indirect table for .got |
| 266 | s->type = SMACHOINDIRECTGOT; |
| 267 | s->reachable = 1; |
| 268 | } |
| 269 | } |
| 270 | |
| 271 | void |
| 272 | machoadddynlib(char *lib) |
| 273 | { |
| 274 | // Will need to store the library name rounded up |
| 275 | // and 24 bytes of header metadata. If not enough |
| 276 | // space, grab another page of initial space at the |
| 277 | // beginning of the output file. |
| 278 | load_budget -= (strlen(lib)+7)/8*8 + 24; |
| 279 | if(load_budget < 0) { |
| 280 | HEADR += 4096; |
| 281 | INITTEXT += 4096; |
| 282 | load_budget += 4096; |
| 283 | } |
| 284 | |
| 285 | if(ndylib%32 == 0) |
| 286 | dylib = erealloc(dylib, (ndylib+32)*sizeof dylib[0]); |
| 287 | dylib[ndylib++] = lib; |
| 288 | } |
| 289 | |
| 290 | static void |
| 291 | machoshbits(MachoSeg *mseg, Section *sect, char *segname) |
| 292 | { |
| 293 | MachoSect *msect; |
| 294 | char buf[40]; |
| 295 | char *p; |
| 296 | |
| 297 | snprint(buf, sizeof buf, "__%s", sect->name+1); |
| 298 | for(p=buf; *p; p++) |
| 299 | if(*p == '.') |
| 300 | *p = '_'; |
| 301 | |
| 302 | msect = newMachoSect(mseg, estrdup(buf), segname); |
| 303 | if(sect->rellen > 0) { |
| 304 | msect->reloc = sect->reloff; |
| 305 | msect->nreloc = sect->rellen / 8; |
| 306 | } |
| 307 | |
| 308 | while(1<<msect->align < sect->align) |
| 309 | msect->align++; |
| 310 | msect->addr = sect->vaddr; |
| 311 | msect->size = sect->len; |
| 312 | |
| 313 | if(sect->vaddr < sect->seg->vaddr + sect->seg->filelen) { |
| 314 | // data in file |
| 315 | if(sect->len > sect->seg->vaddr + sect->seg->filelen - sect->vaddr) |
| 316 | diag("macho cannot represent section %s crossing data and bss", sect->name); |
| 317 | msect->off = sect->seg->fileoff + sect->vaddr - sect->seg->vaddr; |
| 318 | } else { |
| 319 | // zero fill |
| 320 | msect->off = 0; |
| 321 | msect->flag |= 1; |
| 322 | } |
| 323 | |
| 324 | if(sect->rwx & 1) |
| 325 | msect->flag |= 0x400; /* has instructions */ |
| 326 | |
| 327 | if(strcmp(sect->name, ".plt") == 0) { |
| 328 | msect->name = "__symbol_stub1"; |
| 329 | msect->flag = 0x80000408; /* only instructions, code, symbol stubs */ |
| 330 | msect->res1 = 0;//nkind[SymKindLocal]; |
| 331 | msect->res2 = 6; |
| 332 | } |
| 333 | |
| 334 | if(strcmp(sect->name, ".got") == 0) { |
| 335 | msect->name = "__nl_symbol_ptr"; |
| 336 | msect->flag = 6; /* section with nonlazy symbol pointers */ |
| 337 | msect->res1 = linklookup(ctxt, ".linkedit.plt", 0)->size / 4; /* offset into indirect symbol table */ |
| 338 | } |
| 339 | } |
| 340 | |
| 341 | void |
| 342 | asmbmacho(void) |
| 343 | { |
| 344 | vlong v, w; |
| 345 | vlong va; |
| 346 | int a, i; |
| 347 | MachoHdr *mh; |
| 348 | MachoSeg *ms; |
| 349 | MachoLoad *ml; |
| 350 | Section *sect; |
| 351 | |
| 352 | /* apple MACH */ |
| 353 | va = INITTEXT - HEADR; |
| 354 | mh = getMachoHdr(); |
| 355 | switch(thechar){ |
| 356 | default: |
| 357 | diag("unknown mach architecture"); |
| 358 | errorexit(); |
| 359 | case '6': |
| 360 | mh->cpu = MACHO_CPU_AMD64; |
| 361 | mh->subcpu = MACHO_SUBCPU_X86; |
| 362 | break; |
| 363 | case '8': |
| 364 | mh->cpu = MACHO_CPU_386; |
| 365 | mh->subcpu = MACHO_SUBCPU_X86; |
| 366 | break; |
| 367 | } |
| 368 | |
| 369 | ms = nil; |
| 370 | if(linkmode == LinkExternal) { |
| 371 | /* segment for entire file */ |
| 372 | ms = newMachoSeg("", 40); |
| 373 | ms->fileoffset = segtext.fileoff; |
| 374 | ms->filesize = segdata.fileoff + segdata.filelen - segtext.fileoff; |
| 375 | } |
| 376 | |
| 377 | /* segment for zero page */ |
| 378 | if(linkmode != LinkExternal) { |
| 379 | ms = newMachoSeg("__PAGEZERO", 0); |
| 380 | ms->vsize = va; |
| 381 | } |
| 382 | |
| 383 | /* text */ |
| 384 | v = rnd(HEADR+segtext.len, INITRND); |
| 385 | if(linkmode != LinkExternal) { |
| 386 | ms = newMachoSeg("__TEXT", 20); |
| 387 | ms->vaddr = va; |
| 388 | ms->vsize = v; |
| 389 | ms->fileoffset = 0; |
| 390 | ms->filesize = v; |
| 391 | ms->prot1 = 7; |
| 392 | ms->prot2 = 5; |
| 393 | } |
| 394 | |
| 395 | for(sect=segtext.sect; sect!=nil; sect=sect->next) |
| 396 | machoshbits(ms, sect, "__TEXT"); |
| 397 | |
| 398 | /* data */ |
| 399 | if(linkmode != LinkExternal) { |
| 400 | w = segdata.len; |
| 401 | ms = newMachoSeg("__DATA", 20); |
| 402 | ms->vaddr = va+v; |
| 403 | ms->vsize = w; |
| 404 | ms->fileoffset = v; |
| 405 | ms->filesize = segdata.filelen; |
| 406 | ms->prot1 = 3; |
| 407 | ms->prot2 = 3; |
| 408 | } |
| 409 | |
| 410 | for(sect=segdata.sect; sect!=nil; sect=sect->next) |
| 411 | machoshbits(ms, sect, "__DATA"); |
| 412 | |
| 413 | if(linkmode != LinkExternal) { |
| 414 | switch(thechar) { |
| 415 | default: |
| 416 | diag("unknown macho architecture"); |
| 417 | errorexit(); |
| 418 | case '6': |
| 419 | ml = newMachoLoad(5, 42+2); /* unix thread */ |
| 420 | ml->data[0] = 4; /* thread type */ |
| 421 | ml->data[1] = 42; /* word count */ |
| 422 | ml->data[2+32] = entryvalue(); /* start pc */ |
| 423 | ml->data[2+32+1] = entryvalue()>>16>>16; // hide >>32 for 8l |
| 424 | break; |
| 425 | case '8': |
| 426 | ml = newMachoLoad(5, 16+2); /* unix thread */ |
| 427 | ml->data[0] = 1; /* thread type */ |
| 428 | ml->data[1] = 16; /* word count */ |
| 429 | ml->data[2+10] = entryvalue(); /* start pc */ |
| 430 | break; |
| 431 | } |
| 432 | } |
| 433 | |
| 434 | if(!debug['d']) { |
| 435 | LSym *s1, *s2, *s3, *s4; |
| 436 | |
| 437 | // must match domacholink below |
| 438 | s1 = linklookup(ctxt, ".machosymtab", 0); |
| 439 | s2 = linklookup(ctxt, ".linkedit.plt", 0); |
| 440 | s3 = linklookup(ctxt, ".linkedit.got", 0); |
| 441 | s4 = linklookup(ctxt, ".machosymstr", 0); |
| 442 | |
| 443 | if(linkmode != LinkExternal) { |
| 444 | ms = newMachoSeg("__LINKEDIT", 0); |
| 445 | ms->vaddr = va+v+rnd(segdata.len, INITRND); |
| 446 | ms->vsize = s1->size + s2->size + s3->size + s4->size; |
| 447 | ms->fileoffset = linkoff; |
| 448 | ms->filesize = ms->vsize; |
| 449 | ms->prot1 = 7; |
| 450 | ms->prot2 = 3; |
| 451 | } |
| 452 | |
| 453 | ml = newMachoLoad(2, 4); /* LC_SYMTAB */ |
| 454 | ml->data[0] = linkoff; /* symoff */ |
| 455 | ml->data[1] = nsortsym; /* nsyms */ |
| 456 | ml->data[2] = linkoff + s1->size + s2->size + s3->size; /* stroff */ |
| 457 | ml->data[3] = s4->size; /* strsize */ |
| 458 | |
| 459 | machodysymtab(); |
| 460 | |
| 461 | if(linkmode != LinkExternal) { |
| 462 | ml = newMachoLoad(14, 6); /* LC_LOAD_DYLINKER */ |
| 463 | ml->data[0] = 12; /* offset to string */ |
| 464 | strcpy((char*)&ml->data[1], "/usr/lib/dyld"); |
| 465 | |
| 466 | for(i=0; i<ndylib; i++) { |
| 467 | ml = newMachoLoad(12, 4+(strlen(dylib[i])+1+7)/8*2); /* LC_LOAD_DYLIB */ |
| 468 | ml->data[0] = 24; /* offset of string from beginning of load */ |
| 469 | ml->data[1] = 0; /* time stamp */ |
| 470 | ml->data[2] = 0; /* version */ |
| 471 | ml->data[3] = 0; /* compatibility version */ |
| 472 | strcpy((char*)&ml->data[4], dylib[i]); |
| 473 | } |
| 474 | } |
| 475 | } |
| 476 | |
| 477 | // TODO: dwarf headers go in ms too |
| 478 | if(!debug['s'] && linkmode != LinkExternal) |
| 479 | dwarfaddmachoheaders(); |
| 480 | |
| 481 | a = machowrite(); |
| 482 | if(a > HEADR) |
| 483 | diag("HEADR too small: %d > %d", a, HEADR); |
| 484 | } |
| 485 | |
| 486 | static int |
| 487 | symkind(LSym *s) |
| 488 | { |
| 489 | if(s->type == SDYNIMPORT) |
| 490 | return SymKindUndef; |
| 491 | if(s->cgoexport) |
| 492 | return SymKindExtdef; |
| 493 | return SymKindLocal; |
| 494 | } |
| 495 | |
| 496 | static void |
| 497 | addsym(LSym *s, char *name, int type, vlong addr, vlong size, int ver, LSym *gotype) |
| 498 | { |
| 499 | USED(name); |
| 500 | USED(addr); |
| 501 | USED(size); |
| 502 | USED(ver); |
| 503 | USED(gotype); |
| 504 | |
| 505 | if(s == nil) |
| 506 | return; |
| 507 | |
| 508 | switch(type) { |
| 509 | default: |
| 510 | return; |
| 511 | case 'D': |
| 512 | case 'B': |
| 513 | case 'T': |
| 514 | break; |
| 515 | } |
| 516 | |
| 517 | if(sortsym) { |
| 518 | sortsym[nsortsym] = s; |
| 519 | nkind[symkind(s)]++; |
| 520 | } |
| 521 | nsortsym++; |
| 522 | } |
| 523 | |
| 524 | static int |
| 525 | scmp(const void *p1, const void *p2) |
| 526 | { |
| 527 | LSym *s1, *s2; |
| 528 | int k1, k2; |
| 529 | |
| 530 | s1 = *(LSym**)p1; |
| 531 | s2 = *(LSym**)p2; |
| 532 | |
| 533 | k1 = symkind(s1); |
| 534 | k2 = symkind(s2); |
| 535 | if(k1 != k2) |
| 536 | return k1 - k2; |
| 537 | |
| 538 | return strcmp(s1->extname, s2->extname); |
| 539 | } |
| 540 | |
| 541 | static void |
| 542 | machogenasmsym(void (*put)(LSym*, char*, int, vlong, vlong, int, LSym*)) |
| 543 | { |
| 544 | LSym *s; |
| 545 | |
| 546 | genasmsym(put); |
| 547 | for(s=ctxt->allsym; s; s=s->allsym) |
| 548 | if(s->type == SDYNIMPORT || s->type == SHOSTOBJ) |
| 549 | if(s->reachable) |
| 550 | put(s, nil, 'D', 0, 0, 0, nil); |
| 551 | } |
| 552 | |
| 553 | void |
| 554 | machosymorder(void) |
| 555 | { |
| 556 | int i; |
| 557 | |
| 558 | // On Mac OS X Mountain Lion, we must sort exported symbols |
| 559 | // So we sort them here and pre-allocate dynid for them |
| 560 | // See http://golang.org/issue/4029 |
| 561 | for(i=0; i<ndynexp; i++) |
| 562 | dynexp[i]->reachable = 1; |
| 563 | machogenasmsym(addsym); |
| 564 | sortsym = mal(nsortsym * sizeof sortsym[0]); |
| 565 | nsortsym = 0; |
| 566 | machogenasmsym(addsym); |
| 567 | qsort(sortsym, nsortsym, sizeof sortsym[0], scmp); |
| 568 | for(i=0; i<nsortsym; i++) |
| 569 | sortsym[i]->dynid = i; |
| 570 | } |
| 571 | |
| 572 | static void |
| 573 | machosymtab(void) |
| 574 | { |
| 575 | int i; |
| 576 | LSym *symtab, *symstr, *s, *o; |
| 577 | char *p; |
| 578 | |
| 579 | symtab = linklookup(ctxt, ".machosymtab", 0); |
| 580 | symstr = linklookup(ctxt, ".machosymstr", 0); |
| 581 | |
| 582 | for(i=0; i<nsortsym; i++) { |
| 583 | s = sortsym[i]; |
| 584 | adduint32(ctxt, symtab, symstr->size); |
| 585 | |
| 586 | // Only add _ to C symbols. Go symbols have dot in the name. |
| 587 | if(strstr(s->extname, ".") == nil) |
| 588 | adduint8(ctxt, symstr, '_'); |
| 589 | // replace "·" as ".", because DTrace cannot handle it. |
| 590 | if(strstr(s->extname, "·") == nil) { |
| 591 | addstring(symstr, s->extname); |
| 592 | } else { |
| 593 | for(p = s->extname; *p; p++) { |
| 594 | if((uchar)*p == 0xc2 && (uchar)*(p+1) == 0xb7) { |
| 595 | adduint8(ctxt, symstr, '.'); |
| 596 | p++; |
| 597 | } else { |
| 598 | adduint8(ctxt, symstr, *p); |
| 599 | } |
| 600 | } |
| 601 | adduint8(ctxt, symstr, '\0'); |
| 602 | } |
| 603 | if(s->type == SDYNIMPORT || s->type == SHOSTOBJ) { |
| 604 | adduint8(ctxt, symtab, 0x01); // type N_EXT, external symbol |
| 605 | adduint8(ctxt, symtab, 0); // no section |
| 606 | adduint16(ctxt, symtab, 0); // desc |
| 607 | adduintxx(ctxt, symtab, 0, PtrSize); // no value |
| 608 | } else { |
| 609 | if(s->cgoexport) |
| 610 | adduint8(ctxt, symtab, 0x0f); |
| 611 | else |
| 612 | adduint8(ctxt, symtab, 0x0e); |
| 613 | o = s; |
| 614 | while(o->outer != nil) |
| 615 | o = o->outer; |
| 616 | if(o->sect == nil) { |
| 617 | diag("missing section for %s", s->name); |
| 618 | adduint8(ctxt, symtab, 0); |
| 619 | } else |
| 620 | adduint8(ctxt, symtab, o->sect->extnum); |
| 621 | adduint16(ctxt, symtab, 0); // desc |
| 622 | adduintxx(ctxt, symtab, symaddr(s), PtrSize); |
| 623 | } |
| 624 | } |
| 625 | } |
| 626 | |
| 627 | static void |
| 628 | machodysymtab(void) |
| 629 | { |
| 630 | int n; |
| 631 | MachoLoad *ml; |
| 632 | LSym *s1, *s2, *s3; |
| 633 | |
| 634 | ml = newMachoLoad(11, 18); /* LC_DYSYMTAB */ |
| 635 | |
| 636 | n = 0; |
| 637 | ml->data[0] = n; /* ilocalsym */ |
| 638 | ml->data[1] = nkind[SymKindLocal]; /* nlocalsym */ |
| 639 | n += nkind[SymKindLocal]; |
| 640 | |
| 641 | ml->data[2] = n; /* iextdefsym */ |
| 642 | ml->data[3] = nkind[SymKindExtdef]; /* nextdefsym */ |
| 643 | n += nkind[SymKindExtdef]; |
| 644 | |
| 645 | ml->data[4] = n; /* iundefsym */ |
| 646 | ml->data[5] = nkind[SymKindUndef]; /* nundefsym */ |
| 647 | |
| 648 | ml->data[6] = 0; /* tocoffset */ |
| 649 | ml->data[7] = 0; /* ntoc */ |
| 650 | ml->data[8] = 0; /* modtaboff */ |
| 651 | ml->data[9] = 0; /* nmodtab */ |
| 652 | ml->data[10] = 0; /* extrefsymoff */ |
| 653 | ml->data[11] = 0; /* nextrefsyms */ |
| 654 | |
| 655 | // must match domacholink below |
| 656 | s1 = linklookup(ctxt, ".machosymtab", 0); |
| 657 | s2 = linklookup(ctxt, ".linkedit.plt", 0); |
| 658 | s3 = linklookup(ctxt, ".linkedit.got", 0); |
| 659 | ml->data[12] = linkoff + s1->size; /* indirectsymoff */ |
| 660 | ml->data[13] = (s2->size + s3->size) / 4; /* nindirectsyms */ |
| 661 | |
| 662 | ml->data[14] = 0; /* extreloff */ |
| 663 | ml->data[15] = 0; /* nextrel */ |
| 664 | ml->data[16] = 0; /* locreloff */ |
| 665 | ml->data[17] = 0; /* nlocrel */ |
| 666 | } |
| 667 | |
| 668 | vlong |
| 669 | domacholink(void) |
| 670 | { |
| 671 | int size; |
| 672 | LSym *s1, *s2, *s3, *s4; |
| 673 | |
| 674 | machosymtab(); |
| 675 | |
| 676 | // write data that will be linkedit section |
| 677 | s1 = linklookup(ctxt, ".machosymtab", 0); |
| 678 | s2 = linklookup(ctxt, ".linkedit.plt", 0); |
| 679 | s3 = linklookup(ctxt, ".linkedit.got", 0); |
| 680 | s4 = linklookup(ctxt, ".machosymstr", 0); |
| 681 | |
| 682 | // Force the linkedit section to end on a 16-byte |
| 683 | // boundary. This allows pure (non-cgo) Go binaries |
| 684 | // to be code signed correctly. |
| 685 | // |
| 686 | // Apple's codesign_allocate (a helper utility for |
| 687 | // the codesign utility) can do this fine itself if |
| 688 | // it is run on a dynamic Mach-O binary. However, |
| 689 | // when it is run on a pure (non-cgo) Go binary, where |
| 690 | // the linkedit section is mostly empty, it fails to |
| 691 | // account for the extra padding that it itself adds |
| 692 | // when adding the LC_CODE_SIGNATURE load command |
| 693 | // (which must be aligned on a 16-byte boundary). |
| 694 | // |
| 695 | // By forcing the linkedit section to end on a 16-byte |
| 696 | // boundary, codesign_allocate will not need to apply |
| 697 | // any alignment padding itself, working around the |
| 698 | // issue. |
| 699 | while(s4->size%16) |
| 700 | adduint8(ctxt, s4, 0); |
| 701 | |
| 702 | size = s1->size + s2->size + s3->size + s4->size; |
| 703 | |
| 704 | if(size > 0) { |
| 705 | linkoff = rnd(HEADR+segtext.len, INITRND) + rnd(segdata.filelen, INITRND) + rnd(segdwarf.filelen, INITRND); |
| 706 | cseek(linkoff); |
| 707 | |
| 708 | cwrite(s1->p, s1->size); |
| 709 | cwrite(s2->p, s2->size); |
| 710 | cwrite(s3->p, s3->size); |
| 711 | cwrite(s4->p, s4->size); |
| 712 | } |
| 713 | |
| 714 | return rnd(size, INITRND); |
| 715 | } |
| 716 | |
| 717 | |
| 718 | void |
| 719 | machorelocsect(Section *sect, LSym *first) |
| 720 | { |
| 721 | LSym *sym; |
| 722 | int32 eaddr; |
| 723 | Reloc *r; |
| 724 | |
| 725 | // If main section has no bits, nothing to relocate. |
| 726 | if(sect->vaddr >= sect->seg->vaddr + sect->seg->filelen) |
| 727 | return; |
| 728 | |
| 729 | sect->reloff = cpos(); |
| 730 | for(sym = first; sym != nil; sym = sym->next) { |
| 731 | if(!sym->reachable) |
| 732 | continue; |
| 733 | if(sym->value >= sect->vaddr) |
| 734 | break; |
| 735 | } |
| 736 | |
| 737 | eaddr = sect->vaddr + sect->len; |
| 738 | for(; sym != nil; sym = sym->next) { |
| 739 | if(!sym->reachable) |
| 740 | continue; |
| 741 | if(sym->value >= eaddr) |
| 742 | break; |
| 743 | ctxt->cursym = sym; |
| 744 | |
| 745 | for(r = sym->r; r < sym->r+sym->nr; r++) { |
| 746 | if(r->done) |
| 747 | continue; |
| 748 | if(machoreloc1(r, sym->value+r->off - sect->vaddr) < 0) |
| 749 | diag("unsupported obj reloc %d/%d to %s", r->type, r->siz, r->sym->name); |
| 750 | } |
| 751 | } |
| 752 | |
| 753 | sect->rellen = cpos() - sect->reloff; |
| 754 | } |
| 755 | |
| 756 | void |
| 757 | machoemitreloc(void) |
| 758 | { |
| 759 | Section *sect; |
| 760 | |
| 761 | while(cpos()&7) |
| 762 | cput(0); |
| 763 | |
| 764 | machorelocsect(segtext.sect, ctxt->textp); |
| 765 | for(sect=segtext.sect->next; sect!=nil; sect=sect->next) |
| 766 | machorelocsect(sect, datap); |
| 767 | for(sect=segdata.sect; sect!=nil; sect=sect->next) |
| 768 | machorelocsect(sect, datap); |
| 769 | } |