darwin-user/machload.c

   1 /*
   2  *  Mach-O object file loading
   3  *
   4  *  Copyright (c) 2006 Pierre d'Herbemont
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20 #include <stdio.h>
  21 #include <sys/types.h>
  22 #include <fcntl.h>
  23 #include <sys/stat.h>
  24 #include <errno.h>
  25 #include <unistd.h>
  26 #include <sys/mman.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29
  30 #include "qemu.h"
  31 #include "disas.h"
  32
  33 #include <mach-o/loader.h>
  34 #include <mach-o/fat.h>
  35 #include <mach-o/nlist.h>
  36 #include <mach-o/reloc.h>
  37 #include <mach-o/ppc/reloc.h>
  38
  39 //#define DEBUG_MACHLOAD
  40
  41 #ifdef DEBUG_MACHLOAD
  42 # define DPRINTF(...) do { if(loglevel) fprintf(logfile, __VA_ARGS__); printf(__VA_ARGS__); } while(0)
  43 #else
  44 # define DPRINTF(...) do { if(loglevel) fprintf(logfile, __VA_ARGS__); } while(0)
  45 #endif
  46
  47 # define check_mach_header(x) (x.magic == MH_CIGAM)
  48
  49 extern const char *interp_prefix;
  50
  51 /* we don't have a good implementation for this */
  52 #define DONT_USE_DYLD_SHARED_MAP
  53
  54 /* Pass extra arg to DYLD for debug */
  55 //#define ACTIVATE_DYLD_TRACE
  56
  57 //#define OVERRIDE_DYLINKER
  58
  59 #ifdef OVERRIDE_DYLINKER
  60 # ifdef TARGET_I386
  61 #  define DYLINKER_NAME "/Users/steg/qemu/tests/i386-darwin-env/usr/lib/dyld"
  62 # else
  63 #  define DYLINKER_NAME "/usr/lib/dyld"
  64 # endif
  65 #endif
  66
  67 /* XXX: in an include */
  68 struct nlist_extended
  69 {
  70     union {
  71         char *n_name;
  72         long  n_strx;
  73     } n_un;
  74     unsigned char n_type;
  75     unsigned char n_sect;
  76     short st_desc;
  77     unsigned long st_value;
  78     unsigned long st_size;
  79 };
  80
  81 /* Print symbols in gdb */
  82 void *macho_text_sect = 0;
  83 int   macho_offset = 0;
  84
  85 int load_object(const char *filename, struct target_pt_regs * regs, void ** mh);
  86 void qerror(const char *format, ...);
  87 #ifdef TARGET_I386
  88 typedef struct mach_i386_thread_state {
  89     unsigned int    eax;
  90     unsigned int    ebx;
  91     unsigned int    ecx;
  92     unsigned int    edx;
  93     unsigned int    edi;
  94     unsigned int    esi;
  95     unsigned int    ebp;
  96     unsigned int    esp;
  97     unsigned int    ss;
  98     unsigned int    eflags;
  99     unsigned int    eip;
 100     unsigned int    cs;
 101     unsigned int    ds;
 102     unsigned int    es;
 103     unsigned int    fs;
 104     unsigned int    gs;
 105 } mach_i386_thread_state_t;
 106
 107 void bswap_i386_thread_state(struct mach_i386_thread_state *ts)
 108 {
 109     bswap32s((uint32_t*)&ts->eax);
 110     bswap32s((uint32_t*)&ts->ebx);
 111     bswap32s((uint32_t*)&ts->ecx);
 112     bswap32s((uint32_t*)&ts->edx);
 113     bswap32s((uint32_t*)&ts->edi);
 114     bswap32s((uint32_t*)&ts->esi);
 115     bswap32s((uint32_t*)&ts->ebp);
 116     bswap32s((uint32_t*)&ts->esp);
 117     bswap32s((uint32_t*)&ts->ss);
 118     bswap32s((uint32_t*)&ts->eflags);
 119     bswap32s((uint32_t*)&ts->eip);
 120     bswap32s((uint32_t*)&ts->cs);
 121     bswap32s((uint32_t*)&ts->ds);
 122     bswap32s((uint32_t*)&ts->es);
 123     bswap32s((uint32_t*)&ts->fs);
 124     bswap32s((uint32_t*)&ts->gs);
 125 }
 126 #define target_thread_state mach_i386_thread_state
 127 #define TARGET_CPU_TYPE CPU_TYPE_I386
 128 #define TARGET_CPU_NAME "i386"
 129 #endif
 130
 131 #ifdef TARGET_PPC
 132 struct mach_ppc_thread_state {
 133     unsigned int srr0;      /* Instruction address register (PC) */
 134     unsigned int srr1;    /* Machine state register (supervisor) */
 135     unsigned int r0;
 136     unsigned int r1;
 137     unsigned int r2;
 138     unsigned int r3;
 139     unsigned int r4;
 140     unsigned int r5;
 141     unsigned int r6;
 142     unsigned int r7;
 143     unsigned int r8;
 144     unsigned int r9;
 145     unsigned int r10;
 146     unsigned int r11;
 147     unsigned int r12;
 148     unsigned int r13;
 149     unsigned int r14;
 150     unsigned int r15;
 151     unsigned int r16;
 152     unsigned int r17;
 153     unsigned int r18;
 154     unsigned int r19;
 155     unsigned int r20;
 156     unsigned int r21;
 157     unsigned int r22;
 158     unsigned int r23;
 159     unsigned int r24;
 160     unsigned int r25;
 161     unsigned int r26;
 162     unsigned int r27;
 163     unsigned int r28;
 164     unsigned int r29;
 165     unsigned int r30;
 166     unsigned int r31;
 167
 168     unsigned int cr;        /* Condition register */
 169     unsigned int xer;    /* User's integer exception register */
 170     unsigned int lr;    /* Link register */
 171     unsigned int ctr;    /* Count register */
 172     unsigned int mq;    /* MQ register (601 only) */
 173
 174     unsigned int vrsave;    /* Vector Save Register */
 175 };
 176
 177 void bswap_ppc_thread_state(struct mach_ppc_thread_state *ts)
 178 {
 179     bswap32s((uint32_t*)&ts->srr0);
 180     bswap32s((uint32_t*)&ts->srr1);
 181     bswap32s((uint32_t*)&ts->r0);
 182     bswap32s((uint32_t*)&ts->r1);
 183     bswap32s((uint32_t*)&ts->r2);
 184     bswap32s((uint32_t*)&ts->r3);
 185     bswap32s((uint32_t*)&ts->r4);
 186     bswap32s((uint32_t*)&ts->r5);
 187     bswap32s((uint32_t*)&ts->r6);
 188     bswap32s((uint32_t*)&ts->r7);
 189     bswap32s((uint32_t*)&ts->r8);
 190     bswap32s((uint32_t*)&ts->r9);
 191     bswap32s((uint32_t*)&ts->r10);
 192     bswap32s((uint32_t*)&ts->r11);
 193     bswap32s((uint32_t*)&ts->r12);
 194     bswap32s((uint32_t*)&ts->r13);
 195     bswap32s((uint32_t*)&ts->r14);
 196     bswap32s((uint32_t*)&ts->r15);
 197     bswap32s((uint32_t*)&ts->r16);
 198     bswap32s((uint32_t*)&ts->r17);
 199     bswap32s((uint32_t*)&ts->r18);
 200     bswap32s((uint32_t*)&ts->r19);
 201     bswap32s((uint32_t*)&ts->r20);
 202     bswap32s((uint32_t*)&ts->r21);
 203     bswap32s((uint32_t*)&ts->r22);
 204     bswap32s((uint32_t*)&ts->r23);
 205     bswap32s((uint32_t*)&ts->r24);
 206     bswap32s((uint32_t*)&ts->r25);
 207     bswap32s((uint32_t*)&ts->r26);
 208     bswap32s((uint32_t*)&ts->r27);
 209     bswap32s((uint32_t*)&ts->r28);
 210     bswap32s((uint32_t*)&ts->r29);
 211     bswap32s((uint32_t*)&ts->r30);
 212     bswap32s((uint32_t*)&ts->r31);
 213
 214     bswap32s((uint32_t*)&ts->cr);
 215     bswap32s((uint32_t*)&ts->xer);
 216     bswap32s((uint32_t*)&ts->lr);
 217     bswap32s((uint32_t*)&ts->ctr);
 218     bswap32s((uint32_t*)&ts->mq);
 219
 220     bswap32s((uint32_t*)&ts->vrsave);
 221 }
 222
 223 #define target_thread_state mach_ppc_thread_state
 224 #define TARGET_CPU_TYPE CPU_TYPE_POWERPC
 225 #define TARGET_CPU_NAME "PowerPC"
 226 #endif
 227
 228 struct target_thread_command {
 229     unsigned long    cmd;    /* LC_THREAD or  LC_UNIXTHREAD */
 230     unsigned long    cmdsize;    /* total size of this command */
 231     unsigned long flavor;    /* flavor of thread state */
 232     unsigned long count;        /* count of longs in thread state */
 233     struct target_thread_state state;  /* thread state for this flavor */
 234 };
 235
 236 void bswap_tc(struct target_thread_command *tc)
 237 {
 238     bswap32s((uint32_t*)(&tc->flavor));
 239     bswap32s((uint32_t*)&tc->count);
 240 #if defined(TARGET_I386)
 241     bswap_i386_thread_state(&tc->state);
 242 #elif defined(TARGET_PPC)
 243     bswap_ppc_thread_state(&tc->state);
 244 #else
 245 # error unknown TARGET_CPU_TYPE
 246 #endif
 247 }
 248
 249 void bswap_mh(struct mach_header *mh)
 250 {
 251     bswap32s((uint32_t*)(&mh->magic));
 252     bswap32s((uint32_t*)&mh->cputype);
 253     bswap32s((uint32_t*)&mh->cpusubtype);
 254     bswap32s((uint32_t*)&mh->filetype);
 255     bswap32s((uint32_t*)&mh->ncmds);
 256     bswap32s((uint32_t*)&mh->sizeofcmds);
 257     bswap32s((uint32_t*)&mh->flags);
 258 }
 259
 260 void bswap_lc(struct load_command *lc)
 261 {
 262     bswap32s((uint32_t*)&lc->cmd);
 263     bswap32s((uint32_t*)&lc->cmdsize);
 264 }
 265
 266
 267 void bswap_fh(struct fat_header *fh)
 268 {
 269     bswap32s((uint32_t*)&fh->magic);
 270     bswap32s((uint32_t*)&fh->nfat_arch);
 271 }
 272
 273 void bswap_fa(struct fat_arch *fa)
 274 {
 275     bswap32s((uint32_t*)&fa->cputype);
 276     bswap32s((uint32_t*)&fa->cpusubtype);
 277     bswap32s((uint32_t*)&fa->offset);
 278     bswap32s((uint32_t*)&fa->size);
 279     bswap32s((uint32_t*)&fa->align);
 280 }
 281
 282 void bswap_segcmd(struct segment_command *sc)
 283 {
 284     bswap32s((uint32_t*)&sc->vmaddr);
 285     bswap32s((uint32_t*)&sc->vmsize);
 286     bswap32s((uint32_t*)&sc->fileoff);
 287     bswap32s((uint32_t*)&sc->filesize);
 288     bswap32s((uint32_t*)&sc->maxprot);
 289     bswap32s((uint32_t*)&sc->initprot);
 290     bswap32s((uint32_t*)&sc->nsects);
 291     bswap32s((uint32_t*)&sc->flags);
 292 }
 293
 294 void bswap_symtabcmd(struct symtab_command *stc)
 295 {
 296     bswap32s((uint32_t*)&stc->cmd);
 297     bswap32s((uint32_t*)&stc->cmdsize);
 298     bswap32s((uint32_t*)&stc->symoff);
 299     bswap32s((uint32_t*)&stc->nsyms);
 300     bswap32s((uint32_t*)&stc->stroff);
 301     bswap32s((uint32_t*)&stc->strsize);
 302 }
 303
 304 void bswap_sym(struct nlist *n)
 305 {
 306     bswap32s((uint32_t*)&n->n_un.n_strx);
 307     bswap16s((uint16_t*)&n->n_desc);
 308     bswap32s((uint32_t*)&n->n_value);
 309 }
 310
 311 int load_thread(struct mach_header *mh, struct target_thread_command *tc, struct target_pt_regs * regs, int fd, int mh_pos, int need_bswap)
 312 {
 313     int entry;
 314     if(need_bswap)
 315         bswap_tc(tc);
 316 #if defined(TARGET_I386)
 317     entry = tc->state.eip;
 318     DPRINTF(" eax 0x%.8x\n ebx 0x%.8x\n ecx 0x%.8x\n edx 0x%.8x\n edi 0x%.8x\n esi 0x%.8x\n ebp 0x%.8x\n esp 0x%.8x\n ss 0x%.8x\n eflags 0x%.8x\n eip 0x%.8x\n cs 0x%.8x\n ds 0x%.8x\n es 0x%.8x\n fs 0x%.8x\n gs 0x%.8x\n",
 319             tc->state.eax, tc->state.ebx, tc->state.ecx, tc->state.edx, tc->state.edi, tc->state.esi, tc->state.ebp,
 320             tc->state.esp, tc->state.ss, tc->state.eflags, tc->state.eip, tc->state.cs, tc->state.ds, tc->state.es,
 321             tc->state.fs, tc->state.gs );
 322 #define reg_copy(reg)   regs->reg = tc->state.reg
 323     if(regs)
 324     {
 325         reg_copy(eax);
 326         reg_copy(ebx);
 327         reg_copy(ecx);
 328         reg_copy(edx);
 329
 330         reg_copy(edi);
 331         reg_copy(esi);
 332
 333         reg_copy(ebp);
 334         reg_copy(esp);
 335
 336         reg_copy(eflags);
 337         reg_copy(eip);
 338     /*
 339         reg_copy(ss);
 340         reg_copy(cs);
 341         reg_copy(ds);
 342         reg_copy(es);
 343         reg_copy(fs);
 344         reg_copy(gs);*/
 345     }
 346 #undef reg_copy
 347 #elif defined(TARGET_PPC)
 348     entry =  tc->state.srr0;
 349 #endif
 350     DPRINTF("load_thread: entry 0x%x\n", entry);
 351     return entry;
 352 }
 353
 354 int load_dylinker(struct mach_header *mh, struct dylinker_command *dc, int fd, int mh_pos, int need_bswap)
 355 {
 356     int size;
 357     char * dylinker_name;
 358     size = dc->cmdsize - sizeof(struct dylinker_command);
 359
 360     if(need_bswap)
 361         dylinker_name = (char*)(bswap_32(dc->name.offset)+(int)dc);
 362     else
 363         dylinker_name = (char*)((dc->name.offset)+(int)dc);
 364
 365 #ifdef OVERRIDE_DYLINKER
 366     dylinker_name = DYLINKER_NAME;
 367 #else
 368     if(asprintf(&dylinker_name, "%s%s", interp_prefix, dylinker_name) == -1)
 369         qerror("can't allocate the new dylinker name\n");
 370 #endif
 371
 372     DPRINTF("dylinker_name %s\n", dylinker_name);
 373     return load_object(dylinker_name, NULL, NULL);
 374 }
 375
 376 int load_segment(struct mach_header *mh, struct segment_command *sc, int fd, int mh_pos, int need_bswap, int fixed, int slide)
 377 {
 378     unsigned long addr = sc->vmaddr;
 379     unsigned long size = sc->filesize;
 380     unsigned long error = 0;
 381
 382     if(need_bswap)
 383         bswap_segcmd(sc);
 384
 385     if(sc->vmaddr == 0)
 386     {
 387         DPRINTF("load_segment: sc->vmaddr == 0 returning\n");
 388         return -1;
 389     }
 390
 391     if (strcmp(sc->segname, "__PAGEZERO") == 0)
 392     {
 393         DPRINTF("load_segment: __PAGEZERO returning\n");
 394         return -1;
 395     }
 396
 397     /* Right now mmap memory */
 398     /* XXX: should check to see that the space is free, because MAP_FIXED is dangerous */
 399     DPRINTF("load_segment: mmaping %s to 0x%x-(0x%x|0x%x) + 0x%x\n", sc->segname, sc->vmaddr, sc->filesize, sc->vmsize, slide);
 400
 401     if(sc->filesize > 0)
 402     {
 403         int opt = 0;
 404
 405         if(fixed)
 406             opt |= MAP_FIXED;
 407
 408         DPRINTF("sc->vmaddr 0x%x slide 0x%x add 0x%x\n", slide, sc->vmaddr, sc->vmaddr+slide);
 409
 410         addr = target_mmap(sc->vmaddr+slide, sc->filesize,  sc->initprot, opt, fd, mh_pos + sc->fileoff);
 411
 412         if(addr==-1)
 413             qerror("load_segment: can't mmap at 0x%x\n", sc->vmaddr+slide);
 414
 415         error = addr-sc->vmaddr;
 416     }
 417     else
 418     {
 419         addr = sc->vmaddr+slide;
 420         error = slide;
 421     }
 422
 423     if(sc->vmsize > sc->filesize)
 424     {
 425         addr += sc->filesize;
 426         size = sc->vmsize-sc->filesize;
 427         addr = target_mmap(addr, size, sc->initprot, MAP_ANONYMOUS | MAP_FIXED, -1, 0);
 428         if(addr==-1)
 429             qerror("load_segment: can't mmap at 0x%x\n", sc->vmaddr+slide);
 430     }
 431
 432     return error;
 433 }
 434
 435 void *load_data(int fd, long offset, unsigned int size)
 436 {
 437     char *data;
 438
 439     data = malloc(size);
 440     if (!data)
 441         return NULL;
 442     lseek(fd, offset, SEEK_SET);
 443     if (read(fd, data, size) != size) {
 444         free(data);
 445         return NULL;
 446     }
 447     return data;
 448 }
 449
 450 /* load a mach-o object file */
 451 int load_object(const char *filename, struct target_pt_regs * regs, void ** mh)
 452 {
 453     int need_bswap = 0;
 454     int entry_point = 0;
 455     int dyld_entry_point = 0;
 456     int slide, mmapfixed;
 457     int fd;
 458     struct load_command *lcmds, *lc;
 459     int is_fat = 0;
 460     unsigned int i, magic;
 461     int mach_hdr_pos = 0;
 462     struct mach_header mach_hdr;
 463
 464     /* for symbol lookup whith -d flag. */
 465     struct symtab_command *    symtabcmd = 0;
 466     struct nlist_extended *symtab, *sym;
 467     struct nlist     *symtab_std, *syment;
 468     char            *strtab;
 469
 470     fd = open(filename, O_RDONLY);
 471     if (fd < 0)
 472         qerror("can't open file '%s'", filename);
 473
 474     /* Read magic header.  */
 475     if (read(fd, &magic, sizeof (magic)) != sizeof (magic))
 476         qerror("unable to read Magic of '%s'", filename);
 477
 478     /* Check Mach identification.  */
 479     if(magic == MH_MAGIC)
 480     {
 481         is_fat = 0;
 482         need_bswap = 0;
 483     } else if (magic == MH_CIGAM)
 484     {
 485         is_fat = 0;
 486         need_bswap = 1;
 487     } else if (magic == FAT_MAGIC)
 488     {
 489         is_fat = 1;
 490         need_bswap = 0;
 491     } else if (magic == FAT_CIGAM)
 492     {
 493         is_fat = 1;
 494         need_bswap = 1;
 495     }
 496     else
 497         qerror("Not a Mach-O file.", filename);
 498
 499     DPRINTF("loading %s %s...\n", filename, is_fat ? "[FAT]": "[REGULAR]");
 500     if(is_fat)
 501     {
 502         int found = 0;
 503         struct fat_header fh;
 504         struct fat_arch *fa;
 505
 506         lseek(fd, 0, SEEK_SET);
 507
 508         /* Read Fat header.  */
 509         if (read(fd, &fh, sizeof (fh)) != sizeof (fh))
 510             qerror("unable to read file header");
 511
 512         if(need_bswap)
 513             bswap_fh(&fh);
 514
 515         /* Read Fat Arch.  */
 516         fa = malloc(sizeof(struct fat_arch)*fh.nfat_arch);
 517
 518         if (read(fd, fa, sizeof(struct fat_arch)*fh.nfat_arch) != sizeof(struct fat_arch)*fh.nfat_arch)
 519             qerror("unable to read file header");
 520
 521         for( i = 0; i < fh.nfat_arch; i++, fa++)
 522         {
 523             if(need_bswap)
 524                 bswap_fa(fa);
 525             if(fa->cputype == TARGET_CPU_TYPE)
 526             {
 527                 mach_hdr_pos = fa->offset;
 528                 lseek(fd, mach_hdr_pos, SEEK_SET);
 529
 530                 /* Read Mach header.  */
 531
 532                 if (read(fd, &mach_hdr, sizeof(struct mach_header)) != sizeof (struct mach_header))
 533                     qerror("unable to read file header");
 534
 535                 if(mach_hdr.magic == MH_MAGIC)
 536                     need_bswap = 0;
 537                 else if (mach_hdr.magic == MH_CIGAM)
 538                     need_bswap = 1;
 539                 else
 540                     qerror("Invalid mach header in Fat Mach-O File");
 541                 found = 1;
 542                 break;
 543             }
 544         }
 545         if(!found)
 546             qerror("%s: No %s CPU found in FAT Header", filename, TARGET_CPU_NAME);
 547     }
 548     else
 549     {
 550         lseek(fd, 0, SEEK_SET);
 551         /* Read Mach header */
 552         if (read(fd, &mach_hdr, sizeof (mach_hdr)) != sizeof (mach_hdr))
 553             qerror("%s: unable to read file header", filename);
 554     }
 555
 556     if(need_bswap)
 557         bswap_mh(&mach_hdr);
 558
 559     if ((mach_hdr.cputype) != TARGET_CPU_TYPE)
 560         qerror("%s: Unsupported CPU 0x%x (only 0x%x(%s) supported)", filename, mach_hdr.cputype, TARGET_CPU_TYPE, TARGET_CPU_NAME);
 561
 562
 563     switch(mach_hdr.filetype)
 564     {
 565         case MH_EXECUTE:  break;
 566         case MH_FVMLIB:
 567         case MH_DYLIB:
 568         case MH_DYLINKER: break;
 569         default:
 570             qerror("%s: Unsupported Mach type (0x%x)", filename, mach_hdr.filetype);
 571     }
 572
 573     /* read segment headers */
 574     lcmds = malloc(mach_hdr.sizeofcmds);
 575
 576     if(read(fd, lcmds, mach_hdr.sizeofcmds) != mach_hdr.sizeofcmds)
 577             qerror("%s: unable to read load_command", filename);
 578     slide = 0;
 579     mmapfixed = 0;
 580     for(i=0, lc = lcmds; i < (mach_hdr.ncmds) ; i++)
 581     {
 582
 583         if(need_bswap)
 584             bswap_lc(lc);
 585         switch(lc->cmd)
 586         {
 587             case LC_SEGMENT:
 588                 /* The main_exe can't be relocated */
 589                 if(mach_hdr.filetype == MH_EXECUTE)
 590                     mmapfixed = 1;
 591
 592                 slide = load_segment(&mach_hdr, (struct segment_command*)lc, fd, mach_hdr_pos, need_bswap, mmapfixed, slide);
 593
 594                 /* other segment must be mapped according to slide exactly, if load_segment did something */
 595                 if(slide != -1)
 596                     mmapfixed = 1;
 597                 else
 598                     slide = 0; /* load_segment didn't map the segment */
 599
 600                 if(mach_hdr.filetype == MH_EXECUTE && slide != 0)
 601                     qerror("%s: Warning executable can't be mapped at the right address (offset: 0x%x)\n", filename, slide);
 602
 603                 if(strcmp(((struct segment_command*)(lc))->segname, "__TEXT") == 0)
 604                 {
 605                     /* Text section */
 606                     if(mach_hdr.filetype == MH_EXECUTE)
 607                     {
 608                         /* return the mach_header */
 609                         *mh = (void*)(((struct segment_command*)(lc))->vmaddr + slide);
 610                     }
 611                     else
 612                     {
 613                         /* it is dyld save the section for gdb, we will be interested in dyld symbol
 614                            while debuging */
 615                         macho_text_sect = (void*)(((struct segment_command*)(lc))->vmaddr + slide);
 616                         macho_offset = slide;
 617                     }
 618                 }
 619                 break;
 620             case LC_LOAD_DYLINKER:
 621                 dyld_entry_point = load_dylinker( &mach_hdr, (struct dylinker_command*)lc, fd, mach_hdr_pos, need_bswap );
 622                 break;
 623             case LC_LOAD_DYLIB:
 624                 /* dyld will do that for us */
 625                 break;
 626             case LC_THREAD:
 627             case LC_UNIXTHREAD:
 628                 {
 629                 struct target_pt_regs * _regs;
 630                 if(mach_hdr.filetype == MH_DYLINKER)
 631                     _regs = regs;
 632                 else
 633                     _regs = 0;
 634                 entry_point = load_thread( &mach_hdr, (struct target_thread_command*)lc, _regs, fd, mach_hdr_pos, need_bswap );
 635                 }
 636                 break;
 637             case LC_SYMTAB:
 638                 /* Save the symtab and strtab */
 639                 symtabcmd = (struct symtab_command *)lc;
 640                 break;
 641             case LC_ID_DYLINKER:
 642             case LC_ID_DYLIB:
 643             case LC_UUID:
 644             case LC_DYSYMTAB:
 645             case LC_TWOLEVEL_HINTS:
 646             case LC_PREBIND_CKSUM:
 647             case LC_SUB_LIBRARY:
 648                 break;
 649             default: fprintf(stderr, "warning: unkown command 0x%x in '%s'\n", lc->cmd, filename);
 650         }
 651         lc = (struct load_command*)((int)(lc)+(lc->cmdsize));
 652     }
 653
 654     if(symtabcmd)
 655     {
 656         if(need_bswap)
 657             bswap_symtabcmd(symtabcmd);
 658
 659         symtab_std = load_data(fd, symtabcmd->symoff+mach_hdr_pos, symtabcmd->nsyms * sizeof(struct nlist));
 660         strtab = load_data(fd, symtabcmd->stroff+mach_hdr_pos, symtabcmd->strsize);
 661
 662         symtab = malloc(sizeof(struct nlist_extended) * symtabcmd->nsyms);
 663
 664         if(need_bswap)
 665         {
 666             for(i = 0, syment = symtab_std; i < symtabcmd->nsyms; i++, syment++)
 667                 bswap_sym(syment);
 668         }
 669
 670         for(i = 0, sym = symtab, syment = symtab_std; i < symtabcmd->nsyms; i++, sym++, syment++)
 671         {
 672             struct nlist *sym_follow, *sym_next = 0;
 673             unsigned int j;
 674             memset(sym, 0, sizeof(*sym));
 675
 676             sym->n_type = syment->n_type;
 677             if ( syment->n_type & N_STAB ) /* Debug symbols are skipped */
 678                 continue;
 679
 680             memcpy(sym, syment, sizeof(*syment));
 681
 682             /* Find the following symbol in order to get the current symbol size */
 683             for(j = 0, sym_follow = symtab_std; j < symtabcmd->nsyms; j++, sym_follow++) {
 684                 if ( sym_follow->n_type & N_STAB || !(sym_follow->n_value > sym->st_value))
 685                     continue;
 686                 if(!sym_next) {
 687                     sym_next = sym_follow;
 688                     continue;
 689                 }
 690                 if(!(sym_next->n_value > sym_follow->n_value))
 691                     continue;
 692                 sym_next = sym_follow;
 693             }
 694             if(sym_next)
 695                 sym->st_size = sym_next->n_value - sym->st_value;
 696             else
 697                 sym->st_size = 10; /* XXX: text_sec_hdr->size + text_sec_hdr->offset - sym->st_value; */
 698
 699             sym->st_value += slide;
 700         }
 701
 702         free((void*)symtab_std);
 703
 704         {
 705             DPRINTF("saving symtab of %s (%d symbol(s))\n", filename, symtabcmd->nsyms);
 706             struct syminfo *s;
 707             s = malloc(sizeof(*s));
 708             s->disas_symtab = symtab;
 709             s->disas_strtab = strtab;
 710             s->disas_num_syms = symtabcmd->nsyms;
 711             s->next = syminfos;
 712             syminfos = s;
 713         }
 714     }
 715     close(fd);
 716     if(mach_hdr.filetype == MH_EXECUTE && dyld_entry_point)
 717         return dyld_entry_point;
 718     else
 719         return entry_point+slide;
 720 }
 721
 722 extern unsigned long stack_size;
 723
 724 unsigned long setup_arg_pages(void * mh, char ** argv, char ** env)
 725 {
 726     unsigned long stack_base, error, size;
 727     int i;
 728     int * stack;
 729     int argc, envc;
 730
 731     /* Create enough stack to hold everything.  If we don't use
 732      * it for args, we'll use it for something else...
 733      */
 734     size = stack_size;
 735
 736     error = target_mmap(0,
 737                         size + qemu_host_page_size,
 738                         PROT_READ | PROT_WRITE,
 739                         MAP_PRIVATE | MAP_ANONYMOUS,
 740                         -1, 0);
 741     if (error == -1)
 742         qerror("stk mmap");
 743
 744     /* we reserve one extra page at the top of the stack as guard */
 745     target_mprotect(error + size, qemu_host_page_size, PROT_NONE);
 746
 747     stack_base = error + size;
 748     stack = (void*)stack_base;
 749 /*
 750  *    | STRING AREA |
 751  *    +-------------+
 752  *    |      0      |
 753 *    +-------------+
 754  *    |  apple[n]   |
 755  *    +-------------+
 756  *           :
 757  *    +-------------+
 758  *    |  apple[0]   |
 759  *    +-------------+
 760  *    |      0      |
 761  *    +-------------+
 762  *    |    env[n]   |
 763  *    +-------------+
 764  *           :
 765  *           :
 766  *    +-------------+
 767  *    |    env[0]   |
 768  *    +-------------+
 769  *    |      0      |
 770  *    +-------------+
 771  *    | arg[argc-1] |
 772  *    +-------------+
 773  *           :
 774  *           :
 775  *    +-------------+
 776  *    |    arg[0]   |
 777  *    +-------------+
 778  *    |     argc    |
 779  *    +-------------+
 780  * sp->    |      mh     | address of where the a.out's file offset 0 is in memory
 781  *    +-------------+
 782 */
 783     /* Construct the stack Stack grows down */
 784     stack--;
 785
 786     /* XXX: string should go up there */
 787
 788     *stack = 0;
 789     stack--;
 790
 791     /* Push the absolute path of our executable */
 792     DPRINTF("pushing apple %s (0x%x)\n", (char*)argv[0], (int)argv[0]);
 793     stl(stack, (int) argv[0]);
 794
 795     stack--;
 796
 797     stl(stack, 0);
 798     stack--;
 799
 800     /* Get envc */
 801     for(envc = 0; env[envc]; envc++);
 802
 803     for(i = envc-1; i >= 0; i--)
 804     {
 805         DPRINTF("pushing env %s (0x%x)\n", (char*)env[i], (int)env[i]);
 806         stl(stack, (int)env[i]);
 807         stack--;
 808
 809         /* XXX: remove that when string will be on top of the stack */
 810         page_set_flags((int)env[i], (int)(env[i]+strlen(env[i])), PROT_READ | PAGE_VALID);
 811     }
 812
 813     /* Add on the stack the interp_prefix choosen if so */
 814     if(interp_prefix[0])
 815     {
 816         char *dyld_root;
 817         asprintf(&dyld_root, "DYLD_ROOT_PATH=%s", interp_prefix);
 818         page_set_flags((int)dyld_root, (int)(dyld_root+strlen(interp_prefix)+1), PROT_READ | PAGE_VALID);
 819
 820         stl(stack, (int)dyld_root);
 821         stack--;
 822     }
 823
 824 #ifdef DONT_USE_DYLD_SHARED_MAP
 825     {
 826         char *shared_map_mode;
 827         asprintf(&shared_map_mode, "DYLD_SHARED_REGION=avoid");
 828         page_set_flags((int)shared_map_mode, (int)(shared_map_mode+strlen(shared_map_mode)+1), PROT_READ | PAGE_VALID);
 829
 830         stl(stack, (int)shared_map_mode);
 831         stack--;
 832     }
 833 #endif
 834
 835 #ifdef ACTIVATE_DYLD_TRACE
 836     char * extra_env_static[] = {"DYLD_DEBUG_TRACE=yes",
 837     "DYLD_PREBIND_DEBUG=3", "DYLD_UNKNOW_TRACE=yes",
 838     "DYLD_PRINT_INITIALIZERS=yes",
 839     "DYLD_PRINT_SEGMENTS=yes", "DYLD_PRINT_REBASINGS=yes", "DYLD_PRINT_BINDINGS=yes", "DYLD_PRINT_INITIALIZERS=yes", "DYLD_PRINT_WARNINGS=yes" };
 840
 841     char ** extra_env = malloc(sizeof(extra_env_static));
 842     bcopy(extra_env_static, extra_env, sizeof(extra_env_static));
 843     page_set_flags((int)extra_env, (int)((void*)extra_env+sizeof(extra_env_static)), PROT_READ | PAGE_VALID);
 844
 845     for(i = 0; i<9; i++)
 846     {
 847         DPRINTF("pushing (extra) env %s (0x%x)\n", (char*)extra_env[i], (int)extra_env[i]);
 848         stl(stack, (int) extra_env[i]);
 849         stack--;
 850     }
 851 #endif
 852
 853     stl(stack, 0);
 854     stack--;
 855
 856     /* Get argc */
 857     for(argc = 0; argv[argc]; argc++);
 858
 859     for(i = argc-1; i >= 0; i--)
 860     {
 861         DPRINTF("pushing arg %s (0x%x)\n", (char*)argv[i], (int)argv[i]);
 862         stl(stack, (int) argv[i]);
 863         stack--;
 864
 865         /* XXX: remove that when string will be on top of the stack */
 866         page_set_flags((int)argv[i], (int)(argv[i]+strlen(argv[i])), PROT_READ | PAGE_VALID);
 867     }
 868
 869     DPRINTF("pushing argc %d \n", argc);
 870     stl(stack, argc);
 871     stack--;
 872
 873     DPRINTF("pushing mh 0x%x \n", (int)mh);
 874     stl(stack, (int) mh);
 875
 876     /* Stack points on the mh */
 877     return (unsigned long)stack;
 878 }
 879
 880 int mach_exec(const char * filename, char ** argv, char ** envp,
 881              struct target_pt_regs * regs)
 882 {
 883     int entrypoint, stack;
 884     void * mh; /* the Mach Header that will be  used by dyld */
 885
 886     DPRINTF("mach_exec at 0x%x\n", (int)mach_exec);
 887
 888     entrypoint = load_object(filename, regs, &mh);
 889     stack = setup_arg_pages(mh, argv, envp);
 890 #if defined(TARGET_I386)
 891     regs->eip = entrypoint;
 892     regs->esp = stack;
 893 #elif defined(TARGET_PPC)
 894     regs->nip = entrypoint;
 895     regs->gpr[1] = stack;
 896 #endif
 897     DPRINTF("mach_exec returns eip set to 0x%x esp 0x%x mh 0x%x\n", entrypoint, stack, (int)mh);
 898
 899     if(!entrypoint)
 900         qerror("%s: no entry point!\n", filename);
 901
 902     return 0;
 903 }