Add an index entry for "minibuffer-only frame".
[emacs.git] / src / unexmacosx.c
blob2e77d3e17bcd214ccbaa4dc4efa7623ca96ec5dd
1 /* Dump Emacs in Mach-O format for use on Mac OS X.
2 Copyright (C) 2001-2012 Free Software Foundation, Inc.
4 This file is part of GNU Emacs.
6 GNU Emacs is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
11 GNU Emacs 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
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
19 /* Contributed by Andrew Choi (akochoi@mac.com). */
21 /* Documentation note.
23 Consult the following documents/files for a description of the
24 Mach-O format: the file loader.h, man pages for Mach-O and ld, old
25 NEXTSTEP documents of the Mach-O format. The tool otool dumps the
26 mach header (-h option) and the load commands (-l option) in a
27 Mach-O file. The tool nm on Mac OS X displays the symbol table in
28 a Mach-O file. For examples of unexec for the Mach-O format, see
29 the file unexnext.c in the GNU Emacs distribution, the file
30 unexdyld.c in the Darwin port of GNU Emacs 20.7, and unexdyld.c in
31 the Darwin port of XEmacs 21.1. Also the Darwin Libc source
32 contains the source code for malloc_freezedry and malloc_jumpstart.
33 Read that to see what they do. This file was written completely
34 from scratch, making use of information from the above sources. */
36 /* The Mac OS X implementation of unexec makes use of Darwin's `zone'
37 memory allocator. All calls to malloc, realloc, and free in Emacs
38 are redirected to unexec_malloc, unexec_realloc, and unexec_free in
39 this file. When temacs is run, all memory requests are handled in
40 the zone EmacsZone. The Darwin memory allocator library calls
41 maintain the data structures to manage this zone. Dumping writes
42 its contents to data segments of the executable file. When emacs
43 is run, the loader recreates the contents of the zone in memory.
44 However since the initialization routine of the zone memory
45 allocator is run again, this `zone' can no longer be used as a
46 heap. That is why emacs uses the ordinary malloc system call to
47 allocate memory. Also, when a block of memory needs to be
48 reallocated and the new size is larger than the old one, a new
49 block must be obtained by malloc and the old contents copied to
50 it. */
52 /* Peculiarity of the Mach-O files generated by ld in Mac OS X
53 (possible causes of future bugs if changed).
55 The file offset of the start of the __TEXT segment is zero. Since
56 the Mach header and load commands are located at the beginning of a
57 Mach-O file, copying the contents of the __TEXT segment from the
58 input file overwrites them in the output file. Despite this,
59 unexec works fine as written below because the segment load command
60 for __TEXT appears, and is therefore processed, before all other
61 load commands except the segment load command for __PAGEZERO, which
62 remains unchanged.
64 Although the file offset of the start of the __TEXT segment is
65 zero, none of the sections it contains actually start there. In
66 fact, the earliest one starts a few hundred bytes beyond the end of
67 the last load command. The linker option -headerpad controls the
68 minimum size of this padding. Its setting can be changed in
69 s/darwin.h. A value of 0x690, e.g., leaves room for 30 additional
70 load commands for the newly created __DATA segments (at 56 bytes
71 each). Unexec fails if there is not enough room for these new
72 segments.
74 The __TEXT segment contains the sections __text, __cstring,
75 __picsymbol_stub, and __const and the __DATA segment contains the
76 sections __data, __la_symbol_ptr, __nl_symbol_ptr, __dyld, __bss,
77 and __common. The other segments do not contain any sections.
78 These sections are copied from the input file to the output file,
79 except for __data, __bss, and __common, which are dumped from
80 memory. The types of the sections __bss and __common are changed
81 from S_ZEROFILL to S_REGULAR. Note that the number of sections and
82 their relative order in the input and output files remain
83 unchanged. Otherwise all n_sect fields in the nlist records in the
84 symbol table (specified by the LC_SYMTAB load command) will have to
85 be changed accordingly.
88 /* config.h #define:s malloc/realloc/free and then includes stdlib.h.
89 We want the undefined versions, but if config.h includes stdlib.h
90 with the #define:s in place, the prototypes will be wrong and we get
91 warnings. To prevent that, include stdlib.h before config.h. */
93 #include <stdlib.h>
94 #include <config.h>
95 #undef malloc
96 #undef realloc
97 #undef free
99 #include "unexec.h"
101 #include <stdio.h>
102 #include <fcntl.h>
103 #include <stdarg.h>
104 #include <sys/types.h>
105 #include <unistd.h>
106 #include <mach/mach.h>
107 #include <mach-o/loader.h>
108 #include <mach-o/reloc.h>
109 #if defined (__ppc__)
110 #include <mach-o/ppc/reloc.h>
111 #endif
112 #ifdef HAVE_MALLOC_MALLOC_H
113 #include <malloc/malloc.h>
114 #else
115 #include <objc/malloc.h>
116 #endif
118 #include <assert.h>
120 #ifdef _LP64
121 #define mach_header mach_header_64
122 #define segment_command segment_command_64
123 #undef VM_REGION_BASIC_INFO_COUNT
124 #define VM_REGION_BASIC_INFO_COUNT VM_REGION_BASIC_INFO_COUNT_64
125 #undef VM_REGION_BASIC_INFO
126 #define VM_REGION_BASIC_INFO VM_REGION_BASIC_INFO_64
127 #undef LC_SEGMENT
128 #define LC_SEGMENT LC_SEGMENT_64
129 #define vm_region vm_region_64
130 #define section section_64
131 #undef MH_MAGIC
132 #define MH_MAGIC MH_MAGIC_64
133 #endif
135 #define VERBOSE 1
137 /* Size of buffer used to copy data from the input file to the output
138 file in function unexec_copy. */
139 #define UNEXEC_COPY_BUFSZ 1024
141 /* Regions with memory addresses above this value are assumed to be
142 mapped to dynamically loaded libraries and will not be dumped. */
143 #define VM_DATA_TOP (20 * 1024 * 1024)
145 /* Type of an element on the list of regions to be dumped. */
146 struct region_t {
147 vm_address_t address;
148 vm_size_t size;
149 vm_prot_t protection;
150 vm_prot_t max_protection;
152 struct region_t *next;
155 /* Head and tail of the list of regions to be dumped. */
156 static struct region_t *region_list_head = 0;
157 static struct region_t *region_list_tail = 0;
159 /* Pointer to array of load commands. */
160 static struct load_command **lca;
162 /* Number of load commands. */
163 static int nlc;
165 /* The highest VM address of segments loaded by the input file.
166 Regions with addresses beyond this are assumed to be allocated
167 dynamically and thus require dumping. */
168 static vm_address_t infile_lc_highest_addr = 0;
170 /* The lowest file offset used by the all sections in the __TEXT
171 segments. This leaves room at the beginning of the file to store
172 the Mach-O header. Check this value against header size to ensure
173 the added load commands for the new __DATA segments did not
174 overwrite any of the sections in the __TEXT segment. */
175 static unsigned long text_seg_lowest_offset = 0x10000000;
177 /* Mach header. */
178 static struct mach_header mh;
180 /* Offset at which the next load command should be written. */
181 static unsigned long curr_header_offset = sizeof (struct mach_header);
183 /* Offset at which the next segment should be written. */
184 static unsigned long curr_file_offset = 0;
186 static unsigned long pagesize;
187 #define ROUNDUP_TO_PAGE_BOUNDARY(x) (((x) + pagesize - 1) & ~(pagesize - 1))
189 static int infd, outfd;
191 static int in_dumped_exec = 0;
193 static malloc_zone_t *emacs_zone;
195 /* file offset of input file's data segment */
196 static off_t data_segment_old_fileoff = 0;
198 static struct segment_command *data_segment_scp;
200 static void unexec_error (const char *format, ...) NO_RETURN;
202 /* Read N bytes from infd into memory starting at address DEST.
203 Return true if successful, false otherwise. */
204 static int
205 unexec_read (void *dest, size_t n)
207 return n == read (infd, dest, n);
210 /* Write COUNT bytes from memory starting at address SRC to outfd
211 starting at offset DEST. Return true if successful, false
212 otherwise. */
213 static int
214 unexec_write (off_t dest, const void *src, size_t count)
216 if (lseek (outfd, dest, SEEK_SET) != dest)
217 return 0;
219 return write (outfd, src, count) == count;
222 /* Write COUNT bytes of zeros to outfd starting at offset DEST.
223 Return true if successful, false otherwise. */
224 static int
225 unexec_write_zero (off_t dest, size_t count)
227 char buf[UNEXEC_COPY_BUFSZ];
228 ssize_t bytes;
230 memset (buf, 0, UNEXEC_COPY_BUFSZ);
231 if (lseek (outfd, dest, SEEK_SET) != dest)
232 return 0;
234 while (count > 0)
236 bytes = count > UNEXEC_COPY_BUFSZ ? UNEXEC_COPY_BUFSZ : count;
237 if (write (outfd, buf, bytes) != bytes)
238 return 0;
239 count -= bytes;
242 return 1;
245 /* Copy COUNT bytes from starting offset SRC in infd to starting
246 offset DEST in outfd. Return true if successful, false
247 otherwise. */
248 static int
249 unexec_copy (off_t dest, off_t src, ssize_t count)
251 ssize_t bytes_read;
252 ssize_t bytes_to_read;
254 char buf[UNEXEC_COPY_BUFSZ];
256 if (lseek (infd, src, SEEK_SET) != src)
257 return 0;
259 if (lseek (outfd, dest, SEEK_SET) != dest)
260 return 0;
262 while (count > 0)
264 bytes_to_read = count > UNEXEC_COPY_BUFSZ ? UNEXEC_COPY_BUFSZ : count;
265 bytes_read = read (infd, buf, bytes_to_read);
266 if (bytes_read <= 0)
267 return 0;
268 if (write (outfd, buf, bytes_read) != bytes_read)
269 return 0;
270 count -= bytes_read;
273 return 1;
276 /* Debugging and informational messages routines. */
278 static void
279 unexec_error (const char *format, ...)
281 va_list ap;
283 va_start (ap, format);
284 fprintf (stderr, "unexec: ");
285 vfprintf (stderr, format, ap);
286 fprintf (stderr, "\n");
287 va_end (ap);
288 exit (1);
291 static void
292 print_prot (vm_prot_t prot)
294 if (prot == VM_PROT_NONE)
295 printf ("none");
296 else
298 putchar (prot & VM_PROT_READ ? 'r' : ' ');
299 putchar (prot & VM_PROT_WRITE ? 'w' : ' ');
300 putchar (prot & VM_PROT_EXECUTE ? 'x' : ' ');
301 putchar (' ');
305 static void
306 print_region (vm_address_t address, vm_size_t size, vm_prot_t prot,
307 vm_prot_t max_prot)
309 printf ("%#10lx %#8lx ", (long) address, (long) size);
310 print_prot (prot);
311 putchar (' ');
312 print_prot (max_prot);
313 putchar ('\n');
316 static void
317 print_region_list (void)
319 struct region_t *r;
321 printf (" address size prot maxp\n");
323 for (r = region_list_head; r; r = r->next)
324 print_region (r->address, r->size, r->protection, r->max_protection);
327 static void
328 print_regions (void)
330 task_t target_task = mach_task_self ();
331 vm_address_t address = (vm_address_t) 0;
332 vm_size_t size;
333 struct vm_region_basic_info info;
334 mach_msg_type_number_t info_count = VM_REGION_BASIC_INFO_COUNT;
335 mach_port_t object_name;
337 printf (" address size prot maxp\n");
339 while (vm_region (target_task, &address, &size, VM_REGION_BASIC_INFO,
340 (vm_region_info_t) &info, &info_count, &object_name)
341 == KERN_SUCCESS && info_count == VM_REGION_BASIC_INFO_COUNT)
343 print_region (address, size, info.protection, info.max_protection);
345 if (object_name != MACH_PORT_NULL)
346 mach_port_deallocate (target_task, object_name);
348 address += size;
352 /* Build the list of regions that need to be dumped. Regions with
353 addresses above VM_DATA_TOP are omitted. Adjacent regions with
354 identical protection are merged. Note that non-writable regions
355 cannot be omitted because they some regions created at run time are
356 read-only. */
357 static void
358 build_region_list (void)
360 task_t target_task = mach_task_self ();
361 vm_address_t address = (vm_address_t) 0;
362 vm_size_t size;
363 struct vm_region_basic_info info;
364 mach_msg_type_number_t info_count = VM_REGION_BASIC_INFO_COUNT;
365 mach_port_t object_name;
366 struct region_t *r;
368 #if VERBOSE
369 printf ("--- List of All Regions ---\n");
370 printf (" address size prot maxp\n");
371 #endif
373 while (vm_region (target_task, &address, &size, VM_REGION_BASIC_INFO,
374 (vm_region_info_t) &info, &info_count, &object_name)
375 == KERN_SUCCESS && info_count == VM_REGION_BASIC_INFO_COUNT)
377 /* Done when we reach addresses of shared libraries, which are
378 loaded in high memory. */
379 if (address >= VM_DATA_TOP)
380 break;
382 #if VERBOSE
383 print_region (address, size, info.protection, info.max_protection);
384 #endif
386 /* If a region immediately follows the previous one (the one
387 most recently added to the list) and has identical
388 protection, merge it with the latter. Otherwise create a
389 new list element for it. */
390 if (region_list_tail
391 && info.protection == region_list_tail->protection
392 && info.max_protection == region_list_tail->max_protection
393 && region_list_tail->address + region_list_tail->size == address)
395 region_list_tail->size += size;
397 else
399 r = (struct region_t *) malloc (sizeof (struct region_t));
401 if (!r)
402 unexec_error ("cannot allocate region structure");
404 r->address = address;
405 r->size = size;
406 r->protection = info.protection;
407 r->max_protection = info.max_protection;
409 r->next = 0;
410 if (region_list_head == 0)
412 region_list_head = r;
413 region_list_tail = r;
415 else
417 region_list_tail->next = r;
418 region_list_tail = r;
421 /* Deallocate (unused) object name returned by
422 vm_region. */
423 if (object_name != MACH_PORT_NULL)
424 mach_port_deallocate (target_task, object_name);
427 address += size;
430 printf ("--- List of Regions to be Dumped ---\n");
431 print_region_list ();
435 #define MAX_UNEXEC_REGIONS 400
437 static int num_unexec_regions;
438 typedef struct {
439 vm_range_t range;
440 vm_size_t filesize;
441 } unexec_region_info;
442 static unexec_region_info unexec_regions[MAX_UNEXEC_REGIONS];
444 static void
445 unexec_regions_recorder (task_t task, void *rr, unsigned type,
446 vm_range_t *ranges, unsigned num)
448 vm_address_t p;
449 vm_size_t filesize;
451 while (num && num_unexec_regions < MAX_UNEXEC_REGIONS)
453 /* Subtract the size of trailing null bytes from filesize. It
454 can be smaller than vmsize in segment commands. In such a
455 case, trailing bytes are initialized with zeros. */
456 for (p = ranges->address + ranges->size; p > ranges->address; p--)
457 if (*(((char *) p)-1))
458 break;
459 filesize = p - ranges->address;
461 unexec_regions[num_unexec_regions].filesize = filesize;
462 unexec_regions[num_unexec_regions++].range = *ranges;
463 printf ("%#10lx (sz: %#8lx/%#8lx)\n", (long) (ranges->address),
464 (long) filesize, (long) (ranges->size));
465 ranges++; num--;
469 static kern_return_t
470 unexec_reader (task_t task, vm_address_t address, vm_size_t size, void **ptr)
472 *ptr = (void *) address;
473 return KERN_SUCCESS;
476 static void
477 find_emacs_zone_regions (void)
479 num_unexec_regions = 0;
481 emacs_zone->introspect->enumerator (mach_task_self (), 0,
482 MALLOC_PTR_REGION_RANGE_TYPE
483 | MALLOC_ADMIN_REGION_RANGE_TYPE,
484 (vm_address_t) emacs_zone,
485 unexec_reader,
486 unexec_regions_recorder);
488 if (num_unexec_regions == MAX_UNEXEC_REGIONS)
489 unexec_error ("find_emacs_zone_regions: too many regions");
492 static int
493 unexec_regions_sort_compare (const void *a, const void *b)
495 vm_address_t aa = ((unexec_region_info *) a)->range.address;
496 vm_address_t bb = ((unexec_region_info *) b)->range.address;
498 if (aa < bb)
499 return -1;
500 else if (aa > bb)
501 return 1;
502 else
503 return 0;
506 static void
507 unexec_regions_merge (void)
509 int i, n;
510 unexec_region_info r;
511 vm_size_t padsize;
513 qsort (unexec_regions, num_unexec_regions, sizeof (unexec_regions[0]),
514 &unexec_regions_sort_compare);
515 n = 0;
516 r = unexec_regions[0];
517 padsize = r.range.address & (pagesize - 1);
518 if (padsize)
520 r.range.address -= padsize;
521 r.range.size += padsize;
522 r.filesize += padsize;
524 for (i = 1; i < num_unexec_regions; i++)
526 if (r.range.address + r.range.size == unexec_regions[i].range.address
527 && r.range.size - r.filesize < 2 * pagesize)
529 r.filesize = r.range.size + unexec_regions[i].filesize;
530 r.range.size += unexec_regions[i].range.size;
532 else
534 unexec_regions[n++] = r;
535 r = unexec_regions[i];
536 padsize = r.range.address & (pagesize - 1);
537 if (padsize)
539 if ((unexec_regions[n-1].range.address
540 + unexec_regions[n-1].range.size) == r.range.address)
541 unexec_regions[n-1].range.size -= padsize;
543 r.range.address -= padsize;
544 r.range.size += padsize;
545 r.filesize += padsize;
549 unexec_regions[n++] = r;
550 num_unexec_regions = n;
554 /* More informational messages routines. */
556 static void
557 print_load_command_name (int lc)
559 switch (lc)
561 case LC_SEGMENT:
562 #ifndef _LP64
563 printf ("LC_SEGMENT ");
564 #else
565 printf ("LC_SEGMENT_64 ");
566 #endif
567 break;
568 case LC_LOAD_DYLINKER:
569 printf ("LC_LOAD_DYLINKER ");
570 break;
571 case LC_LOAD_DYLIB:
572 printf ("LC_LOAD_DYLIB ");
573 break;
574 case LC_SYMTAB:
575 printf ("LC_SYMTAB ");
576 break;
577 case LC_DYSYMTAB:
578 printf ("LC_DYSYMTAB ");
579 break;
580 case LC_UNIXTHREAD:
581 printf ("LC_UNIXTHREAD ");
582 break;
583 case LC_PREBOUND_DYLIB:
584 printf ("LC_PREBOUND_DYLIB");
585 break;
586 case LC_TWOLEVEL_HINTS:
587 printf ("LC_TWOLEVEL_HINTS");
588 break;
589 #ifdef LC_UUID
590 case LC_UUID:
591 printf ("LC_UUID ");
592 break;
593 #endif
594 #ifdef LC_DYLD_INFO
595 case LC_DYLD_INFO:
596 printf ("LC_DYLD_INFO ");
597 break;
598 case LC_DYLD_INFO_ONLY:
599 printf ("LC_DYLD_INFO_ONLY");
600 break;
601 #endif
602 #ifdef LC_VERSION_MIN_MACOSX
603 case LC_VERSION_MIN_MACOSX:
604 printf ("LC_VERSION_MIN_MACOSX");
605 break;
606 #endif
607 #ifdef LC_FUNCTION_STARTS
608 case LC_FUNCTION_STARTS:
609 printf ("LC_FUNCTION_STARTS");
610 break;
611 #endif
612 default:
613 printf ("unknown ");
617 static void
618 print_load_command (struct load_command *lc)
620 print_load_command_name (lc->cmd);
621 printf ("%8d", lc->cmdsize);
623 if (lc->cmd == LC_SEGMENT)
625 struct segment_command *scp;
626 struct section *sectp;
627 int j;
629 scp = (struct segment_command *) lc;
630 printf (" %-16.16s %#10lx %#8lx\n",
631 scp->segname, (long) (scp->vmaddr), (long) (scp->vmsize));
633 sectp = (struct section *) (scp + 1);
634 for (j = 0; j < scp->nsects; j++)
636 printf (" %-16.16s %#10lx %#8lx\n",
637 sectp->sectname, (long) (sectp->addr), (long) (sectp->size));
638 sectp++;
641 else
642 printf ("\n");
645 /* Read header and load commands from input file. Store the latter in
646 the global array lca. Store the total number of load commands in
647 global variable nlc. */
648 static void
649 read_load_commands (void)
651 int i;
653 if (!unexec_read (&mh, sizeof (struct mach_header)))
654 unexec_error ("cannot read mach-o header");
656 if (mh.magic != MH_MAGIC)
657 unexec_error ("input file not in Mach-O format");
659 if (mh.filetype != MH_EXECUTE)
660 unexec_error ("input Mach-O file is not an executable object file");
662 #if VERBOSE
663 printf ("--- Header Information ---\n");
664 printf ("Magic = 0x%08x\n", mh.magic);
665 printf ("CPUType = %d\n", mh.cputype);
666 printf ("CPUSubType = %d\n", mh.cpusubtype);
667 printf ("FileType = 0x%x\n", mh.filetype);
668 printf ("NCmds = %d\n", mh.ncmds);
669 printf ("SizeOfCmds = %d\n", mh.sizeofcmds);
670 printf ("Flags = 0x%08x\n", mh.flags);
671 #endif
673 nlc = mh.ncmds;
674 lca = (struct load_command **) malloc (nlc * sizeof (struct load_command *));
676 for (i = 0; i < nlc; i++)
678 struct load_command lc;
679 /* Load commands are variable-size: so read the command type and
680 size first and then read the rest. */
681 if (!unexec_read (&lc, sizeof (struct load_command)))
682 unexec_error ("cannot read load command");
683 lca[i] = (struct load_command *) malloc (lc.cmdsize);
684 memcpy (lca[i], &lc, sizeof (struct load_command));
685 if (!unexec_read (lca[i] + 1, lc.cmdsize - sizeof (struct load_command)))
686 unexec_error ("cannot read content of load command");
687 if (lc.cmd == LC_SEGMENT)
689 struct segment_command *scp = (struct segment_command *) lca[i];
691 if (scp->vmaddr + scp->vmsize > infile_lc_highest_addr)
692 infile_lc_highest_addr = scp->vmaddr + scp->vmsize;
694 if (strncmp (scp->segname, SEG_TEXT, 16) == 0)
696 struct section *sectp = (struct section *) (scp + 1);
697 int j;
699 for (j = 0; j < scp->nsects; j++)
700 if (sectp->offset < text_seg_lowest_offset)
701 text_seg_lowest_offset = sectp->offset;
706 printf ("Highest address of load commands in input file: %#8lx\n",
707 (unsigned long)infile_lc_highest_addr);
709 printf ("Lowest offset of all sections in __TEXT segment: %#8lx\n",
710 text_seg_lowest_offset);
712 printf ("--- List of Load Commands in Input File ---\n");
713 printf ("# cmd cmdsize name address size\n");
715 for (i = 0; i < nlc; i++)
717 printf ("%1d ", i);
718 print_load_command (lca[i]);
722 /* Copy a LC_SEGMENT load command other than the __DATA segment from
723 the input file to the output file, adjusting the file offset of the
724 segment and the file offsets of sections contained in it. */
725 static void
726 copy_segment (struct load_command *lc)
728 struct segment_command *scp = (struct segment_command *) lc;
729 unsigned long old_fileoff = scp->fileoff;
730 struct section *sectp;
731 int j;
733 scp->fileoff = curr_file_offset;
735 sectp = (struct section *) (scp + 1);
736 for (j = 0; j < scp->nsects; j++)
738 sectp->offset += curr_file_offset - old_fileoff;
739 sectp++;
742 printf ("Writing segment %-16.16s @ %#8lx (%#8lx/%#8lx @ %#10lx)\n",
743 scp->segname, (long) (scp->fileoff), (long) (scp->filesize),
744 (long) (scp->vmsize), (long) (scp->vmaddr));
746 if (!unexec_copy (scp->fileoff, old_fileoff, scp->filesize))
747 unexec_error ("cannot copy segment from input to output file");
748 curr_file_offset += ROUNDUP_TO_PAGE_BOUNDARY (scp->filesize);
750 if (!unexec_write (curr_header_offset, lc, lc->cmdsize))
751 unexec_error ("cannot write load command to header");
753 curr_header_offset += lc->cmdsize;
756 /* Copy a LC_SEGMENT load command for the __DATA segment in the input
757 file to the output file. We assume that only one such segment load
758 command exists in the input file and it contains the sections
759 __data, __bss, __common, __la_symbol_ptr, __nl_symbol_ptr, and
760 __dyld. The first three of these should be dumped from memory and
761 the rest should be copied from the input file. Note that the
762 sections __bss and __common contain no data in the input file
763 because their flag fields have the value S_ZEROFILL. Dumping these
764 from memory makes it necessary to adjust file offset fields in
765 subsequently dumped load commands. Then, create new __DATA segment
766 load commands for regions on the region list other than the one
767 corresponding to the __DATA segment in the input file. */
768 static void
769 copy_data_segment (struct load_command *lc)
771 struct segment_command *scp = (struct segment_command *) lc;
772 struct section *sectp;
773 int j;
774 unsigned long header_offset, old_file_offset;
776 /* The new filesize of the segment is set to its vmsize because data
777 blocks for segments must start at region boundaries. Note that
778 this may leave unused locations at the end of the segment data
779 block because the total of the sizes of all sections in the
780 segment is generally smaller than vmsize. */
781 scp->filesize = scp->vmsize;
783 printf ("Writing segment %-16.16s @ %#8lx (%#8lx/%#8lx @ %#10lx)\n",
784 scp->segname, curr_file_offset, (long)(scp->filesize),
785 (long)(scp->vmsize), (long) (scp->vmaddr));
787 /* Offsets in the output file for writing the next section structure
788 and segment data block, respectively. */
789 header_offset = curr_header_offset + sizeof (struct segment_command);
791 sectp = (struct section *) (scp + 1);
792 for (j = 0; j < scp->nsects; j++)
794 old_file_offset = sectp->offset;
795 sectp->offset = sectp->addr - scp->vmaddr + curr_file_offset;
796 /* The __data section is dumped from memory. The __bss and
797 __common sections are also dumped from memory but their flag
798 fields require changing (from S_ZEROFILL to S_REGULAR). The
799 other three kinds of sections are just copied from the input
800 file. */
801 if (strncmp (sectp->sectname, SECT_DATA, 16) == 0)
803 if (!unexec_write (sectp->offset, (void *) sectp->addr, sectp->size))
804 unexec_error ("cannot write section %s", SECT_DATA);
805 if (!unexec_write (header_offset, sectp, sizeof (struct section)))
806 unexec_error ("cannot write section %s's header", SECT_DATA);
808 else if (strncmp (sectp->sectname, SECT_COMMON, 16) == 0)
810 sectp->flags = S_REGULAR;
811 if (!unexec_write (sectp->offset, (void *) sectp->addr, sectp->size))
812 unexec_error ("cannot write section %s", sectp->sectname);
813 if (!unexec_write (header_offset, sectp, sizeof (struct section)))
814 unexec_error ("cannot write section %s's header", sectp->sectname);
816 else if (strncmp (sectp->sectname, SECT_BSS, 16) == 0)
818 extern char *my_endbss_static;
819 unsigned long my_size;
821 sectp->flags = S_REGULAR;
823 /* Clear uninitialized local variables in statically linked
824 libraries. In particular, function pointers stored by
825 libSystemStub.a, which is introduced in Mac OS X 10.4 for
826 binary compatibility with respect to long double, are
827 cleared so that they will be reinitialized when the
828 dumped binary is executed on other versions of OS. */
829 my_size = (unsigned long)my_endbss_static - sectp->addr;
830 if (!(sectp->addr <= (unsigned long)my_endbss_static
831 && my_size <= sectp->size))
832 unexec_error ("my_endbss_static is not in section %s",
833 sectp->sectname);
834 if (!unexec_write (sectp->offset, (void *) sectp->addr, my_size))
835 unexec_error ("cannot write section %s", sectp->sectname);
836 if (!unexec_write_zero (sectp->offset + my_size,
837 sectp->size - my_size))
838 unexec_error ("cannot write section %s", sectp->sectname);
839 if (!unexec_write (header_offset, sectp, sizeof (struct section)))
840 unexec_error ("cannot write section %s's header", sectp->sectname);
842 else if (strncmp (sectp->sectname, "__la_symbol_ptr", 16) == 0
843 || strncmp (sectp->sectname, "__nl_symbol_ptr", 16) == 0
844 || strncmp (sectp->sectname, "__got", 16) == 0
845 || strncmp (sectp->sectname, "__la_sym_ptr2", 16) == 0
846 || strncmp (sectp->sectname, "__dyld", 16) == 0
847 || strncmp (sectp->sectname, "__const", 16) == 0
848 || strncmp (sectp->sectname, "__cfstring", 16) == 0
849 || strncmp (sectp->sectname, "__gcc_except_tab", 16) == 0
850 || strncmp (sectp->sectname, "__program_vars", 16) == 0
851 || strncmp (sectp->sectname, "__objc_", 7) == 0)
853 if (!unexec_copy (sectp->offset, old_file_offset, sectp->size))
854 unexec_error ("cannot copy section %s", sectp->sectname);
855 if (!unexec_write (header_offset, sectp, sizeof (struct section)))
856 unexec_error ("cannot write section %s's header", sectp->sectname);
858 else
859 unexec_error ("unrecognized section name in __DATA segment");
861 printf (" section %-16.16s at %#8lx - %#8lx (sz: %#8lx)\n",
862 sectp->sectname, (long) (sectp->offset),
863 (long) (sectp->offset + sectp->size), (long) (sectp->size));
865 header_offset += sizeof (struct section);
866 sectp++;
869 curr_file_offset += ROUNDUP_TO_PAGE_BOUNDARY (scp->filesize);
871 if (!unexec_write (curr_header_offset, scp, sizeof (struct segment_command)))
872 unexec_error ("cannot write header of __DATA segment");
873 curr_header_offset += lc->cmdsize;
875 /* Create new __DATA segment load commands for regions on the region
876 list that do not corresponding to any segment load commands in
877 the input file.
879 for (j = 0; j < num_unexec_regions; j++)
881 struct segment_command sc;
883 sc.cmd = LC_SEGMENT;
884 sc.cmdsize = sizeof (struct segment_command);
885 strncpy (sc.segname, SEG_DATA, 16);
886 sc.vmaddr = unexec_regions[j].range.address;
887 sc.vmsize = unexec_regions[j].range.size;
888 sc.fileoff = curr_file_offset;
889 sc.filesize = unexec_regions[j].filesize;
890 sc.maxprot = VM_PROT_READ | VM_PROT_WRITE;
891 sc.initprot = VM_PROT_READ | VM_PROT_WRITE;
892 sc.nsects = 0;
893 sc.flags = 0;
895 printf ("Writing segment %-16.16s @ %#8lx (%#8lx/%#8lx @ %#10lx)\n",
896 sc.segname, (long) (sc.fileoff), (long) (sc.filesize),
897 (long) (sc.vmsize), (long) (sc.vmaddr));
899 if (!unexec_write (sc.fileoff, (void *) sc.vmaddr, sc.filesize))
900 unexec_error ("cannot write new __DATA segment");
901 curr_file_offset += ROUNDUP_TO_PAGE_BOUNDARY (sc.filesize);
903 if (!unexec_write (curr_header_offset, &sc, sc.cmdsize))
904 unexec_error ("cannot write new __DATA segment's header");
905 curr_header_offset += sc.cmdsize;
906 mh.ncmds++;
910 /* Copy a LC_SYMTAB load command from the input file to the output
911 file, adjusting the file offset fields. */
912 static void
913 copy_symtab (struct load_command *lc, long delta)
915 struct symtab_command *stp = (struct symtab_command *) lc;
917 stp->symoff += delta;
918 stp->stroff += delta;
920 printf ("Writing LC_SYMTAB command\n");
922 if (!unexec_write (curr_header_offset, lc, lc->cmdsize))
923 unexec_error ("cannot write symtab command to header");
925 curr_header_offset += lc->cmdsize;
928 /* Fix up relocation entries. */
929 static void
930 unrelocate (const char *name, off_t reloff, int nrel, vm_address_t base)
932 int i, unreloc_count;
933 struct relocation_info reloc_info;
934 struct scattered_relocation_info *sc_reloc_info
935 = (struct scattered_relocation_info *) &reloc_info;
936 vm_address_t location;
938 for (unreloc_count = 0, i = 0; i < nrel; i++)
940 if (lseek (infd, reloff, L_SET) != reloff)
941 unexec_error ("unrelocate: %s:%d cannot seek to reloc_info", name, i);
942 if (!unexec_read (&reloc_info, sizeof (reloc_info)))
943 unexec_error ("unrelocate: %s:%d cannot read reloc_info", name, i);
944 reloff += sizeof (reloc_info);
946 if (sc_reloc_info->r_scattered == 0)
947 switch (reloc_info.r_type)
949 case GENERIC_RELOC_VANILLA:
950 location = base + reloc_info.r_address;
951 if (location >= data_segment_scp->vmaddr
952 && location < (data_segment_scp->vmaddr
953 + data_segment_scp->vmsize))
955 off_t src_off = data_segment_old_fileoff
956 + (location - data_segment_scp->vmaddr);
957 off_t dst_off = data_segment_scp->fileoff
958 + (location - data_segment_scp->vmaddr);
960 if (!unexec_copy (dst_off, src_off, 1 << reloc_info.r_length))
961 unexec_error ("unrelocate: %s:%d cannot copy original value",
962 name, i);
963 unreloc_count++;
965 break;
966 default:
967 unexec_error ("unrelocate: %s:%d cannot handle type = %d",
968 name, i, reloc_info.r_type);
970 else
971 switch (sc_reloc_info->r_type)
973 #if defined (__ppc__)
974 case PPC_RELOC_PB_LA_PTR:
975 /* nothing to do for prebound lazy pointer */
976 break;
977 #endif
978 default:
979 unexec_error ("unrelocate: %s:%d cannot handle scattered type = %d",
980 name, i, sc_reloc_info->r_type);
984 if (nrel > 0)
985 printf ("Fixed up %d/%d %s relocation entries in data segment.\n",
986 unreloc_count, nrel, name);
989 #if __ppc64__
990 /* Rebase r_address in the relocation table. */
991 static void
992 rebase_reloc_address (off_t reloff, int nrel, long linkedit_delta, long diff)
994 int i;
995 struct relocation_info reloc_info;
996 struct scattered_relocation_info *sc_reloc_info
997 = (struct scattered_relocation_info *) &reloc_info;
999 for (i = 0; i < nrel; i++, reloff += sizeof (reloc_info))
1001 if (lseek (infd, reloff - linkedit_delta, L_SET)
1002 != reloff - linkedit_delta)
1003 unexec_error ("rebase_reloc_table: cannot seek to reloc_info");
1004 if (!unexec_read (&reloc_info, sizeof (reloc_info)))
1005 unexec_error ("rebase_reloc_table: cannot read reloc_info");
1007 if (sc_reloc_info->r_scattered == 0
1008 && reloc_info.r_type == GENERIC_RELOC_VANILLA)
1010 reloc_info.r_address -= diff;
1011 if (!unexec_write (reloff, &reloc_info, sizeof (reloc_info)))
1012 unexec_error ("rebase_reloc_table: cannot write reloc_info");
1016 #endif
1018 /* Copy a LC_DYSYMTAB load command from the input file to the output
1019 file, adjusting the file offset fields. */
1020 static void
1021 copy_dysymtab (struct load_command *lc, long delta)
1023 struct dysymtab_command *dstp = (struct dysymtab_command *) lc;
1024 vm_address_t base;
1026 #ifdef _LP64
1027 #if __ppc64__
1029 int i;
1031 base = 0;
1032 for (i = 0; i < nlc; i++)
1033 if (lca[i]->cmd == LC_SEGMENT)
1035 struct segment_command *scp = (struct segment_command *) lca[i];
1037 if (scp->vmaddr + scp->vmsize > 0x100000000
1038 && (scp->initprot & VM_PROT_WRITE) != 0)
1040 base = data_segment_scp->vmaddr;
1041 break;
1045 #else
1046 /* First writable segment address. */
1047 base = data_segment_scp->vmaddr;
1048 #endif
1049 #else
1050 /* First segment address in the file (unless MH_SPLIT_SEGS set). */
1051 base = 0;
1052 #endif
1054 unrelocate ("local", dstp->locreloff, dstp->nlocrel, base);
1055 unrelocate ("external", dstp->extreloff, dstp->nextrel, base);
1057 if (dstp->nextrel > 0) {
1058 dstp->extreloff += delta;
1061 if (dstp->nlocrel > 0) {
1062 dstp->locreloff += delta;
1065 if (dstp->nindirectsyms > 0)
1066 dstp->indirectsymoff += delta;
1068 printf ("Writing LC_DYSYMTAB command\n");
1070 if (!unexec_write (curr_header_offset, lc, lc->cmdsize))
1071 unexec_error ("cannot write symtab command to header");
1073 curr_header_offset += lc->cmdsize;
1075 #if __ppc64__
1076 /* Check if the relocation base needs to be changed. */
1077 if (base == 0)
1079 vm_address_t newbase = 0;
1080 int i;
1082 for (i = 0; i < num_unexec_regions; i++)
1083 if (unexec_regions[i].range.address + unexec_regions[i].range.size
1084 > 0x100000000)
1086 newbase = data_segment_scp->vmaddr;
1087 break;
1090 if (newbase)
1092 rebase_reloc_address (dstp->locreloff, dstp->nlocrel, delta, newbase);
1093 rebase_reloc_address (dstp->extreloff, dstp->nextrel, delta, newbase);
1096 #endif
1099 /* Copy a LC_TWOLEVEL_HINTS load command from the input file to the output
1100 file, adjusting the file offset fields. */
1101 static void
1102 copy_twolevelhints (struct load_command *lc, long delta)
1104 struct twolevel_hints_command *tlhp = (struct twolevel_hints_command *) lc;
1106 if (tlhp->nhints > 0) {
1107 tlhp->offset += delta;
1110 printf ("Writing LC_TWOLEVEL_HINTS command\n");
1112 if (!unexec_write (curr_header_offset, lc, lc->cmdsize))
1113 unexec_error ("cannot write two level hint command to header");
1115 curr_header_offset += lc->cmdsize;
1118 #ifdef LC_DYLD_INFO
1119 /* Copy a LC_DYLD_INFO(_ONLY) load command from the input file to the output
1120 file, adjusting the file offset fields. */
1121 static void
1122 copy_dyld_info (struct load_command *lc, long delta)
1124 struct dyld_info_command *dip = (struct dyld_info_command *) lc;
1126 if (dip->rebase_off > 0)
1127 dip->rebase_off += delta;
1128 if (dip->bind_off > 0)
1129 dip->bind_off += delta;
1130 if (dip->weak_bind_off > 0)
1131 dip->weak_bind_off += delta;
1132 if (dip->lazy_bind_off > 0)
1133 dip->lazy_bind_off += delta;
1134 if (dip->export_off > 0)
1135 dip->export_off += delta;
1137 printf ("Writing ");
1138 print_load_command_name (lc->cmd);
1139 printf (" command\n");
1141 if (!unexec_write (curr_header_offset, lc, lc->cmdsize))
1142 unexec_error ("cannot write dyld info command to header");
1144 curr_header_offset += lc->cmdsize;
1146 #endif
1148 #ifdef LC_FUNCTION_STARTS
1149 /* Copy a LC_FUNCTION_STARTS load command from the input file to the
1150 output file, adjusting the data offset field. */
1151 static void
1152 copy_linkedit_data (struct load_command *lc, long delta)
1154 struct linkedit_data_command *ldp = (struct linkedit_data_command *) lc;
1156 if (ldp->dataoff > 0)
1157 ldp->dataoff += delta;
1159 printf ("Writing ");
1160 print_load_command_name (lc->cmd);
1161 printf (" command\n");
1163 if (!unexec_write (curr_header_offset, lc, lc->cmdsize))
1164 unexec_error ("cannot write linkedit data command to header");
1166 curr_header_offset += lc->cmdsize;
1168 #endif
1170 /* Copy other kinds of load commands from the input file to the output
1171 file, ones that do not require adjustments of file offsets. */
1172 static void
1173 copy_other (struct load_command *lc)
1175 printf ("Writing ");
1176 print_load_command_name (lc->cmd);
1177 printf (" command\n");
1179 if (!unexec_write (curr_header_offset, lc, lc->cmdsize))
1180 unexec_error ("cannot write symtab command to header");
1182 curr_header_offset += lc->cmdsize;
1185 /* Loop through all load commands and dump them. Then write the Mach
1186 header. */
1187 static void
1188 dump_it (void)
1190 int i;
1191 long linkedit_delta = 0;
1193 printf ("--- Load Commands written to Output File ---\n");
1195 for (i = 0; i < nlc; i++)
1196 switch (lca[i]->cmd)
1198 case LC_SEGMENT:
1200 struct segment_command *scp = (struct segment_command *) lca[i];
1201 if (strncmp (scp->segname, SEG_DATA, 16) == 0)
1203 /* save data segment file offset and segment_command for
1204 unrelocate */
1205 if (data_segment_old_fileoff)
1206 unexec_error ("cannot handle multiple DATA segments"
1207 " in input file");
1208 data_segment_old_fileoff = scp->fileoff;
1209 data_segment_scp = scp;
1211 copy_data_segment (lca[i]);
1213 else
1215 if (strncmp (scp->segname, SEG_LINKEDIT, 16) == 0)
1217 if (linkedit_delta)
1218 unexec_error ("cannot handle multiple LINKEDIT segments"
1219 " in input file");
1220 linkedit_delta = curr_file_offset - scp->fileoff;
1223 copy_segment (lca[i]);
1226 break;
1227 case LC_SYMTAB:
1228 copy_symtab (lca[i], linkedit_delta);
1229 break;
1230 case LC_DYSYMTAB:
1231 copy_dysymtab (lca[i], linkedit_delta);
1232 break;
1233 case LC_TWOLEVEL_HINTS:
1234 copy_twolevelhints (lca[i], linkedit_delta);
1235 break;
1236 #ifdef LC_DYLD_INFO
1237 case LC_DYLD_INFO:
1238 case LC_DYLD_INFO_ONLY:
1239 copy_dyld_info (lca[i], linkedit_delta);
1240 break;
1241 #endif
1242 #ifdef LC_FUNCTION_STARTS
1243 case LC_FUNCTION_STARTS:
1244 copy_linkedit_data (lca[i], linkedit_delta);
1245 break;
1246 #endif
1247 default:
1248 copy_other (lca[i]);
1249 break;
1252 if (curr_header_offset > text_seg_lowest_offset)
1253 unexec_error ("not enough room for load commands for new __DATA segments");
1255 printf ("%ld unused bytes follow Mach-O header\n",
1256 text_seg_lowest_offset - curr_header_offset);
1258 mh.sizeofcmds = curr_header_offset - sizeof (struct mach_header);
1259 if (!unexec_write (0, &mh, sizeof (struct mach_header)))
1260 unexec_error ("cannot write final header contents");
1263 /* Take a snapshot of Emacs and make a Mach-O format executable file
1264 from it. The file names of the output and input files are outfile
1265 and infile, respectively. The three other parameters are
1266 ignored. */
1267 void
1268 unexec (const char *outfile, const char *infile)
1270 if (in_dumped_exec)
1271 unexec_error ("Unexec from a dumped executable is not supported.");
1273 pagesize = getpagesize ();
1274 infd = open (infile, O_RDONLY, 0);
1275 if (infd < 0)
1277 unexec_error ("cannot open input file `%s'", infile);
1280 outfd = open (outfile, O_WRONLY | O_TRUNC | O_CREAT, 0755);
1281 if (outfd < 0)
1283 close (infd);
1284 unexec_error ("cannot open output file `%s'", outfile);
1287 build_region_list ();
1288 read_load_commands ();
1290 find_emacs_zone_regions ();
1291 unexec_regions_merge ();
1293 in_dumped_exec = 1;
1295 dump_it ();
1297 close (outfd);
1301 void
1302 unexec_init_emacs_zone (void)
1304 emacs_zone = malloc_create_zone (0, 0);
1305 malloc_set_zone_name (emacs_zone, "EmacsZone");
1308 #ifndef MACOSX_MALLOC_MULT16
1309 #define MACOSX_MALLOC_MULT16 1
1310 #endif
1312 typedef struct unexec_malloc_header {
1313 union {
1314 char c[8];
1315 size_t size;
1316 } u;
1317 } unexec_malloc_header_t;
1319 #if MACOSX_MALLOC_MULT16
1321 #define ptr_in_unexec_regions(p) ((((vm_address_t) (p)) & 8) != 0)
1323 #else
1326 ptr_in_unexec_regions (void *ptr)
1328 int i;
1330 for (i = 0; i < num_unexec_regions; i++)
1331 if ((vm_address_t) ptr - unexec_regions[i].range.address
1332 < unexec_regions[i].range.size)
1333 return 1;
1335 return 0;
1338 #endif
1340 void *
1341 unexec_malloc (size_t size)
1343 if (in_dumped_exec)
1345 void *p;
1347 p = malloc (size);
1348 #if MACOSX_MALLOC_MULT16
1349 assert (((vm_address_t) p % 16) == 0);
1350 #endif
1351 return p;
1353 else
1355 unexec_malloc_header_t *ptr;
1357 ptr = (unexec_malloc_header_t *)
1358 malloc_zone_malloc (emacs_zone, size + sizeof (unexec_malloc_header_t));
1359 ptr->u.size = size;
1360 ptr++;
1361 #if MACOSX_MALLOC_MULT16
1362 assert (((vm_address_t) ptr % 16) == 8);
1363 #endif
1364 return (void *) ptr;
1368 void *
1369 unexec_realloc (void *old_ptr, size_t new_size)
1371 if (in_dumped_exec)
1373 void *p;
1375 if (ptr_in_unexec_regions (old_ptr))
1377 size_t old_size = ((unexec_malloc_header_t *) old_ptr)[-1].u.size;
1378 size_t size = new_size > old_size ? old_size : new_size;
1380 p = (size_t *) malloc (new_size);
1381 if (size)
1382 memcpy (p, old_ptr, size);
1384 else
1386 p = realloc (old_ptr, new_size);
1388 #if MACOSX_MALLOC_MULT16
1389 assert (((vm_address_t) p % 16) == 0);
1390 #endif
1391 return p;
1393 else
1395 unexec_malloc_header_t *ptr;
1397 ptr = (unexec_malloc_header_t *)
1398 malloc_zone_realloc (emacs_zone, (unexec_malloc_header_t *) old_ptr - 1,
1399 new_size + sizeof (unexec_malloc_header_t));
1400 ptr->u.size = new_size;
1401 ptr++;
1402 #if MACOSX_MALLOC_MULT16
1403 assert (((vm_address_t) ptr % 16) == 8);
1404 #endif
1405 return (void *) ptr;
1409 void
1410 unexec_free (void *ptr)
1412 if (ptr == NULL)
1413 return;
1414 if (in_dumped_exec)
1416 if (!ptr_in_unexec_regions (ptr))
1417 free (ptr);
1419 else
1420 malloc_zone_free (emacs_zone, (unexec_malloc_header_t *) ptr - 1);