src/unexnext.c

   1 /* Dump Emacs in macho format.
   2    Copyright (C) 1990, 1993, 2001, 2002, 2003, 2004,
   3                  2005, 2006, 2007  Free Software Foundation, Inc.
   4    Written by Bradley Taylor (btaylor@next.com).
   5
   6 This file is part of GNU Emacs.
   7
   8 GNU Emacs 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, or (at your option)
  11 any later version.
  12
  13 GNU Emacs 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 GNU Emacs; see the file COPYING.  If not, write to
  20 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  21 Boston, MA 02110-1301, USA.  */
  22
  23
  24 #undef __STRICT_BSD__
  25
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <stdarg.h>
  29 #include <mach/mach.h>
  30 #include <mach-o/loader.h>
  31 #include <mach-o/reloc.h>
  32 #include <sys/file.h>
  33 #include <sys/stat.h>
  34 #include <unistd.h>
  35 /* Instead of unistd.h, this used to include libc.h.
  36    "Nelson H. F. Beebe" <beebe@math.utah.edu> says that doesn't work
  37    in system version 3.3.  */
  38
  39
  40 int malloc_cookie;
  41
  42 /*
  43  * Kludge: we don't expect any program data beyond VM_HIGHDATA
  44  * What is really needed is a way to find out from malloc() which
  45  * pages it vm_allocated and write only those out into the data segment.
  46  *
  47  * This kludge may break when we stop using fixed virtual address
  48  * shared libraries. Actually, emacs will probably continue working, but be
  49  * much larger on disk than it needs to be (because non-malloced data will
  50  * be in the file).
  51  */
  52 static const unsigned VM_HIGHDATA = 0x2000000;
  53
  54 typedef struct region_t {
  55         vm_address_t address;
  56         vm_size_t size;
  57         vm_prot_t protection;
  58         vm_prot_t max_protection;
  59         vm_inherit_t inheritance;
  60         boolean_t shared;
  61         port_t object_name;
  62         vm_offset_t offset;
  63 } region_t;
  64
  65
  66 static void
  67 grow(
  68      struct load_command ***the_commands,
  69      unsigned *the_commands_len
  70      )
  71 {
  72         if (*the_commands == NULL) {
  73                 *the_commands_len = 1;
  74                 *the_commands = malloc(sizeof(*the_commands));
  75         } else {
  76                 (*the_commands_len)++;
  77                 *the_commands = realloc(*the_commands,
  78                                         (*the_commands_len *
  79                                          sizeof(**the_commands)));
  80         }
  81 }
  82
  83
  84 static void
  85 save_command(
  86              struct load_command *command,
  87              struct load_command ***the_commands,
  88              unsigned *the_commands_len
  89              )
  90 {
  91         struct load_command **tmp;
  92
  93         grow(the_commands, the_commands_len);
  94         tmp = &(*the_commands)[*the_commands_len - 1];
  95         *tmp = malloc(command->cmdsize);
  96         bcopy(command, *tmp, command->cmdsize);
  97 }
  98
  99 static void
 100 fatal_unexec(char *format, ...)
 101 {
 102         va_list ap;
 103
 104         va_start(ap, format);
 105         fprintf(stderr, "unexec: ");
 106         vfprintf(stderr, format, ap);
 107         fprintf(stderr, "\n");
 108         va_end(ap);
 109 }
 110
 111 static int
 112 read_macho(
 113            int fd,
 114            struct mach_header *the_header,
 115            struct load_command ***the_commands,
 116            unsigned *the_commands_len
 117            )
 118 {
 119         struct load_command command;
 120         struct load_command *buf;
 121         int i;
 122         int size;
 123
 124         if (read(fd, the_header, sizeof(*the_header)) != sizeof(*the_header)) {
 125                 fatal_unexec("cannot read macho header");
 126                 return (0);
 127         }
 128         for (i = 0; i < the_header->ncmds; i++) {
 129                 if (read(fd, &command, sizeof(struct load_command)) !=
 130                     sizeof(struct load_command)) {
 131                         fatal_unexec("cannot read macho load command header");
 132                         return (0);
 133                 }
 134                 size = command.cmdsize - sizeof(struct load_command);
 135                 if (size < 0) {
 136                         fatal_unexec("bogus load command size");
 137                         return (0);
 138                 }
 139                 buf = malloc(command.cmdsize);
 140                 buf->cmd = command.cmd;
 141                 buf->cmdsize = command.cmdsize;
 142                 if (read(fd, ((char *)buf +
 143                               sizeof(struct load_command)),
 144                          size) != size) {
 145                         fatal_unexec("cannot read load command data");
 146                         return (0);
 147                 }
 148                 save_command(buf, the_commands, the_commands_len);
 149         }
 150         return (1);
 151 }
 152
 153 static int
 154 filldatagap(
 155             vm_address_t start_address,
 156             vm_size_t *size,
 157             vm_address_t end_address
 158             )
 159 {
 160         vm_address_t address;
 161         vm_size_t gapsize;
 162
 163         address = (start_address + *size);
 164         gapsize = end_address - address;
 165         *size += gapsize;
 166         if (vm_allocate(task_self(), &address, gapsize,
 167                         FALSE) != KERN_SUCCESS) {
 168                 fatal_unexec("cannot vm_allocate");
 169                 return (0);
 170         }
 171         return (1);
 172 }
 173
 174 static int
 175 get_data_region(
 176                 vm_address_t *address,
 177                 vm_size_t *size
 178                 )
 179 {
 180         region_t region;
 181         kern_return_t ret;
 182         struct section *sect;
 183
 184         sect = (struct section *) getsectbyname(SEG_DATA, SECT_DATA);
 185         region.address = 0;
 186         *address = 0;
 187         for (;;) {
 188                 ret = vm_region(task_self(),
 189                                 &region.address,
 190                                 &region.size,
 191                                 &region.protection,
 192                                 &region.max_protection,
 193                                 &region.inheritance,
 194                                 &region.shared,
 195                                 &region.object_name,
 196                                 &region.offset);
 197                 if (ret != KERN_SUCCESS || region.address >= VM_HIGHDATA) {
 198                         break;
 199                 }
 200                 if (*address != 0) {
 201                         if (region.address > *address + *size) {
 202                                 if (!filldatagap(*address, size,
 203                                                  region.address)) {
 204                                         return (0);
 205                                 }
 206                         }
 207                         *size += region.size;
 208                 } else {
 209                         if (region.address == sect->addr) {
 210                                 *address = region.address;
 211                                 *size = region.size;
 212                         }
 213                 }
 214                 region.address += region.size;
 215         }
 216         return (1);
 217 }
 218
 219 static char *
 220 my_malloc(
 221           vm_size_t size
 222           )
 223 {
 224         vm_address_t address;
 225
 226         if (vm_allocate(task_self(), &address, size, TRUE) != KERN_SUCCESS) {
 227                 return (NULL);
 228         }
 229         return ((char *)address);
 230 }
 231
 232 static void
 233 my_free(
 234         char *buf,
 235         vm_size_t size
 236         )
 237 {
 238         vm_deallocate(task_self(), (vm_address_t)buf, size);
 239 }
 240
 241 static int
 242 unexec_doit(
 243             int infd,
 244             int outfd
 245             )
 246 {
 247         int i;
 248         struct load_command **the_commands = NULL;
 249         unsigned the_commands_len;
 250         struct mach_header the_header;
 251         int fgrowth = 0;
 252         int fdatastart;
 253         int fdatasize;
 254         int size;
 255         struct stat st;
 256         char *buf;
 257         vm_address_t data_address;
 258         vm_size_t data_size;
 259         vm_size_t vmaddr_growth = 0;
 260         vm_size_t dataseg_vmaddr, dataseg_vmend;
 261
 262         struct segment_command *segment;
 263
 264 #ifdef NS_TARGET
 265         unsigned long extreloff = 0;
 266         unsigned long nextrel = 0;
 267         struct dysymtab_command *dysymtab;
 268         struct relocation_info reloc_info;
 269 #endif
 270
 271         if (!read_macho(infd, &the_header, &the_commands, &the_commands_len)) {
 272                 return (0);
 273         }
 274
 275
 276         malloc_cookie = malloc_freezedry ();
 277         if (!get_data_region(&data_address, &data_size)) {
 278                 return (0);
 279         }
 280
 281
 282         /*
 283          * DO NOT USE MALLOC IN THIS SECTION
 284          */
 285         {
 286                 /*
 287                  * Fix offsets
 288                  */
 289                 for (i = 0; i < the_commands_len; i++) {
 290                         switch (the_commands[i]->cmd) {
 291                         case LC_SEGMENT:
 292                                 segment = ((struct segment_command *)
 293                                            the_commands[i]);
 294                                 if (strcmp(segment->segname, SEG_DATA) == 0) {
 295                                         fdatastart = segment->fileoff;
 296                                         fdatasize = segment->filesize;
 297                                         fgrowth = (data_size -
 298                                                    segment->filesize);
 299                                         segment->vmsize = data_size;
 300                                         segment->filesize = data_size;
 301                                         dataseg_vmaddr = segment->vmaddr;
 302                                         dataseg_vmend = segment->vmaddr + segment->vmsize;
 303                                         vmaddr_growth = segment->vmaddr + segment->vmsize;
 304                                 } else {
 305                                         ((struct segment_command *)the_commands[i])->fileoff += fgrowth;
 306                                 }
 307
 308                                 if( strcmp( segment->segname, SEG_LINKEDIT ) == 0 ) {
 309                                         segment->vmaddr = vmaddr_growth;
 310                                 }
 311
 312                                 break;
 313                         case LC_SYMTAB:
 314                                 ((struct symtab_command *)
 315                                  the_commands[i])->symoff += fgrowth;
 316                                 ((struct symtab_command *)
 317                                  the_commands[i])->stroff += fgrowth;
 318                                 break;
 319                         case LC_SYMSEG:
 320                                 ((struct symseg_command *)
 321                                  the_commands[i])->offset += fgrowth;
 322                                 break;
 323 #ifdef NS_TARGET
 324                         case LC_DYSYMTAB:
 325                                 dysymtab = ((struct dysymtab_command *)the_commands[i]);
 326                                 extreloff = dysymtab->extreloff;
 327                                 nextrel = dysymtab->nextrel;
 328                                 dysymtab->indirectsymoff += fgrowth;
 329                                 dysymtab->extreloff += fgrowth;
 330                                 break;
 331 #endif
 332                         default:
 333                                 break;
 334                         }
 335                 }
 336
 337                 /*
 338                  * Write header
 339                  */
 340                 if (write(outfd, &the_header,
 341                           sizeof(the_header)) != sizeof(the_header)) {
 342                         fatal_unexec("cannot write output file");
 343                         return (0);
 344                 }
 345
 346                 /*
 347                  * Write commands
 348                  */
 349                 for (i = 0; i < the_commands_len; i++) {
 350                         if (write(outfd, the_commands[i],
 351                                   the_commands[i]->cmdsize) !=
 352                             the_commands[i]->cmdsize) {
 353                                 fatal_unexec("cannot write output file");
 354                                 return (0);
 355                         }
 356                 }
 357
 358                 /*
 359                  * Write original text
 360                  */
 361                 if (lseek(infd, the_header.sizeofcmds + sizeof(the_header),
 362                           L_SET) < 0) {
 363                         fatal_unexec("cannot seek input file");
 364                         return (0);
 365                 }
 366                 size = fdatastart - (sizeof(the_header) +
 367                                      the_header.sizeofcmds);
 368                 buf = my_malloc(size);
 369                 if (read(infd, buf, size) != size) {
 370                         my_free(buf, size);
 371                         fatal_unexec("cannot read input file");
 372                 }
 373                 if (write(outfd, buf, size) != size) {
 374                         my_free(buf, size);
 375                         fatal_unexec("cannot write output file");
 376                         return (0);
 377                 }
 378                 my_free(buf, size);
 379
 380
 381                 /*
 382                  * Write new data
 383                  */
 384                 if (write(outfd, (char *)data_address,
 385                           data_size) != data_size) {
 386                         fatal_unexec("cannot write output file");
 387                         return (0);
 388                 }
 389
 390         }
 391
 392         /*
 393          * OKAY TO USE MALLOC NOW
 394          */
 395
 396         /*
 397          * Write rest of file
 398          */
 399         fstat(infd, &st);
 400         if (lseek(infd, fdatasize, L_INCR) < 0) {
 401                 fatal_unexec("cannot seek input file");
 402                 return (0);
 403         }
 404         size = st.st_size - lseek(infd, 0, L_INCR);
 405
 406         buf = malloc(size);
 407         if (read(infd, buf, size) != size) {
 408                 free(buf);
 409                 fatal_unexec("cannot read input file");
 410                 return (0);
 411         }
 412         if (write(outfd, buf, size) != size) {
 413                 free(buf);
 414                 fatal_unexec("cannot write output file");
 415                 return (0);
 416         }
 417         free(buf);
 418
 419 #ifdef NS_TARGET
 420         /*
 421          * Fix up relocation entries in the data segment.
 422          */
 423
 424         if (lseek(infd, extreloff, L_SET) < 0) {
 425                 fatal_unexec("cannot seek input file");
 426                 return (0);
 427         }
 428
 429         for (i = 0; i < nextrel; i++)
 430         {
 431           long zeroval = 0;
 432
 433           if (read(infd, &reloc_info, sizeof (reloc_info)) != sizeof (reloc_info)) {
 434             fatal_unexec("cannot read input file");
 435             return (0);
 436           }
 437           if (reloc_info.r_address >= dataseg_vmaddr && reloc_info.r_address < dataseg_vmend)
 438           {
 439             if (lseek (outfd, fdatastart + reloc_info.r_address - dataseg_vmaddr, L_SET) < 0 ) {
 440               fatal_unexec("cannot seek input file");
 441               return (0);
 442             }
 443             switch (reloc_info.r_length) {
 444               case 0:
 445                 if (write(outfd, &zeroval, 1) != 1) {
 446                         fatal_unexec("cannot write output file");
 447                         return (0);
 448                 }
 449                 break;
 450               case 1:
 451                 if (write(outfd, &zeroval, 2) != 2) {
 452                         fatal_unexec("cannot write output file");
 453                         return (0);
 454                 }
 455                 break;
 456               case 2:
 457                 if (write(outfd, &zeroval, 4) != 4) {
 458                         fatal_unexec("cannot write output file");
 459                         return (0);
 460                 }
 461                 break;
 462             }
 463           }
 464         }
 465 #endif
 466
 467         return (1);
 468 }
 469
 470 void
 471 unexec(
 472        char *outfile,
 473        char *infile
 474        )
 475 {
 476         int infd;
 477         int outfd;
 478         char tmpbuf[L_tmpnam];
 479         char *tmpfile;
 480
 481         infd = open(infile, O_RDONLY, 0);
 482         if (infd < 0) {
 483                 fatal_unexec("cannot open input file `%s'", infile);
 484                 exit(1);
 485         }
 486
 487         tmpnam(tmpbuf);
 488         tmpfile = rindex(tmpbuf, '/');
 489         if (tmpfile == NULL) {
 490                 tmpfile = tmpbuf;
 491         } else {
 492                 tmpfile++;
 493         }
 494         outfd = open(tmpfile, O_WRONLY|O_TRUNC|O_CREAT, 0755);
 495         if (outfd < 0) {
 496                 close(infd);
 497                 fatal_unexec("cannot open tmp file `%s'", tmpfile);
 498                 exit(1);
 499         }
 500         if (!unexec_doit(infd, outfd)) {
 501                 close(infd);
 502                 close(outfd);
 503                 unlink(tmpfile);
 504                 exit(1);
 505         }
 506         close(infd);
 507         close(outfd);
 508         if (rename(tmpfile, outfile) < 0) {
 509                 unlink(tmpfile);
 510                 fatal_unexec("cannot rename `%s' to `%s'", tmpfile, outfile);
 511                 exit(1);
 512         }
 513 }
 514
 515 /* arch-tag: 9796bdc3-c050-417a-b2f5-4cfd31032634
 516    (do not change this comment) */