1 /* Copyright (C) 1985, 1986, 1987, 1988 Free Software Foundation, Inc.
2
3 This program is free software; you can redistribute it and/or modify
4 it under the terms of the GNU General Public License as published by
5 the Free Software Foundation; either version 1, or (at your option)
6 any later version.
7
8 This program is distributed in the hope that it will be useful,
9 but WITHOUT ANY WARRANTY; without even the implied warranty of
10 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 GNU General Public License for more details.
12
13 You should have received a copy of the GNU General Public License
14 along with this program; if not, write to the Free Software
15 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
16
17 In other words, you are welcome to use, share and improve this program.
18 You are forbidden to forbid anyone else to use, share and improve
19 what you give them. Help stamp out software-hoarding! */
20
21
22 /*
23 * unexec.c - Convert a running program into an a.out file.
24 *
25 * Author: Spencer W. Thomas
26 * Computer Science Dept.
27 * University of Utah
28 * Date: Tue Mar 2 1982
29 * Modified heavily since then.
30 *
31 * Synopsis:
32 * unexec (new_name, a_name, data_start, bss_start, entry_address)
33 * char *new_name, *a_name;
34 * unsigned data_start, bss_start, entry_address;
35 *
36 * Takes a snapshot of the program and makes an a.out format file in the
37 * file named by the string argument new_name.
38 * If a_name is non-NULL, the symbol table will be taken from the given file.
39 * On some machines, an existing a_name file is required.
40 *
41 * The boundaries within the a.out file may be adjusted with the data_start
42 * and bss_start arguments. Either or both may be given as 0 for defaults.
43 *
44 * Data_start gives the boundary between the text segment and the data
45 * segment of the program. The text segment can contain shared, read-only
46 * program code and literal data, while the data segment is always unshared
47 * and unprotected. Data_start gives the lowest unprotected address.
48 * The value you specify may be rounded down to a suitable boundary
49 * as required by the machine you are using.
50 *
51 * Specifying zero for data_start means the boundary between text and data
52 * should not be the same as when the program was loaded.
53 * If NO_REMAP is defined, the argument data_start is ignored and the
54 * segment boundaries are never changed.
55 *
56 * Bss_start indicates how much of the data segment is to be saved in the
57 * a.out file and restored when the program is executed. It gives the lowest
58 * unsaved address, and is rounded up to a page boundary. The default when 0
59 * is given assumes that the entire data segment is to be stored, including
60 * the previous data and bss as well as any additional storage allocated with
61 * break (2).
62 *
63 * The new file is set up to start at entry_address.
64 *
65 * If you make improvements I'd like to get them too.
66 * harpo!utah-cs!thomas, thomas@Utah-20
67 *
68 */
69
70 /* Modified to support SysVr3 shared libraries by James Van Artsdalen
71 * of Dell Computer Corporation. james@bigtex.cactus.org.
72 */
73
74 /* There are several compilation parameters affecting unexec:
75
76 * COFF
77
78 Define this if your system uses COFF for executables.
79 Otherwise we assume you use Berkeley format.
80
81 * NO_REMAP
82
83 Define this if you do not want to try to save Emacs's pure data areas
84 as part of the text segment.
85
86 Saving them as text is good because it allows users to share more.
87
88 However, on machines that locate the text area far from the data area,
89 the boundary cannot feasibly be moved. Such machines require
90 NO_REMAP.
91
92 Also, remapping can cause trouble with the built-in startup routine
93 /lib/crt0.o, which defines `environ' as an initialized variable.
94 Dumping `environ' as pure does not work! So, to use remapping,
95 you must write a startup routine for your machine in Emacs's crt0.c.
96 If NO_REMAP is defined, Emacs uses the system's crt0.o.
97
98 * SECTION_ALIGNMENT
99
100 Some machines that use COFF executables require that each section
101 start on a certain boundary *in the COFF file*. Such machines should
102 define SECTION_ALIGNMENT to a mask of the low-order bits that must be
103 zero on such a boundary. This mask is used to control padding between
104 segments in the COFF file.
105
106 If SECTION_ALIGNMENT is not defined, the segments are written
107 consecutively with no attempt at alignment. This is right for
108 unmodified system V.
109
110 * SEGMENT_MASK
111
112 Some machines require that the beginnings and ends of segments
113 *in core* be on certain boundaries. For most machines, a page
114 boundary is sufficient. That is the default. When a larger
115 boundary is needed, define SEGMENT_MASK to a mask of
116 the bits that must be zero on such a boundary.
117
118 * A_TEXT_OFFSET(HDR)
119
120 Some machines count the a.out header as part of the size of the text
121 segment (a_text); they may actually load the header into core as the
122 first data in the text segment. Some have additional padding between
123 the header and the real text of the program that is counted in a_text.
124
125 For these machines, define A_TEXT_OFFSET(HDR) to examine the header
126 structure HDR and return the number of bytes to add to `a_text'
127 before writing it (above and beyond the number of bytes of actual
128 program text). HDR's standard fields are already correct, except that
129 this adjustment to the `a_text' field has not yet been made;
130 thus, the amount of offset can depend on the data in the file.
131
132 * A_TEXT_SEEK(HDR)
133
134 If defined, this macro specifies the number of bytes to seek into the
135 a.out file before starting to write the text segment.a
136
137 * EXEC_MAGIC
138
139 For machines using COFF, this macro, if defined, is a value stored
140 into the magic number field of the output file.
141
142 * ADJUST_EXEC_HEADER
143
144 This macro can be used to generate statements to adjust or
145 initialize nonstandard fields in the file header
146
147 * ADDR_CORRECT(ADDR)
148
149 Macro to correct an int which is the bit pattern of a pointer to a byte
150 into an int which is the number of a byte.
151
152 This macro has a default definition which is usually right.
153 This default definition is a no-op on most machines (where a
154 pointer looks like an int) but not on all machines.
155
156 */
157
158 #ifndef emacs
159 #define PERROR(arg) perror (arg); return -1
160 #else
161 #include "config.h"
162 #define PERROR(file) report_error (file, new)
163 #endif
164
165 #ifndef CANNOT_DUMP /* all rest of file! */
166
167 #ifndef CANNOT_UNEXEC /* most of rest of file */
168
169 #include <a.out.h>
170 /* Define getpagesize () if the system does not.
171 Note that this may depend on symbols defined in a.out.h
172 */
173 #include "getpagesize.h"
174
175 #ifndef makedev /* Try to detect types.h already loaded */
176 #include <sys/types.h>
177 #endif
178 #include <stdio.h>
179 #include <sys/stat.h>
180 #include <errno.h>
181
182 extern char *start_of_text (); /* Start of text */
183 extern char *start_of_data (); /* Start of initialized data */
184
185 #ifdef COFF
186 #ifndef USG
187 #ifndef STRIDE
188 #ifndef UMAX
189 #ifndef sun386
190 /* I have a suspicion that these are turned off on all systems
191 and can be deleted. Try it in version 19. */
192 #include <filehdr.h>
193 #include <aouthdr.h>
194 #include <scnhdr.h>
195 #include <syms.h>
196 #endif /* not sun386 */
197 #endif /* not UMAX */
198 #endif /* Not STRIDE */
199 #endif /* not USG */
200 static long block_copy_start; /* Old executable start point */
201 static struct filehdr f_hdr; /* File header */
202 static struct aouthdr f_ohdr; /* Optional file header (a.out) */
203 long bias; /* Bias to add for growth */
204 long lnnoptr; /* Pointer to line-number info within file */
205 #define SYMS_START block_copy_start
206
207 static long text_scnptr;
208 static long data_scnptr;
209
210 #else /* not COFF */
211
212 extern char *sbrk ();
213
214 #define SYMS_START ((long) N_SYMOFF (ohdr))
215
216 /* Some machines override the structure name for an a.out header. */
217 #ifndef EXEC_HDR_TYPE
218 #define EXEC_HDR_TYPE struct exec
219 #endif
220
221 #ifdef HPUX
222 #ifdef HP9000S200_ID
223 #define MY_ID HP9000S200_ID
224 #else
225 #include <model.h>
226 #define MY_ID MYSYS
227 #endif /* no HP9000S200_ID */
228 static MAGIC OLDMAGIC = {MY_ID, SHARE_MAGIC};
229 static MAGIC NEWMAGIC = {MY_ID, DEMAND_MAGIC};
230 #define N_TXTOFF(x) TEXT_OFFSET(x)
231 #define N_SYMOFF(x) LESYM_OFFSET(x)
232 static EXEC_HDR_TYPE hdr, ohdr;
233
234 #else /* not HPUX */
235
236 #if defined (USG) && !defined (IBMRTAIX) && !defined (IRIS)
237 static struct bhdr hdr, ohdr;
238 #define a_magic fmagic
239 #define a_text tsize
240 #define a_data dsize
241 #define a_bss bsize
242 #define a_syms ssize
243 #define a_trsize rtsize
244 #define a_drsize rdsize
245 #define a_entry entry
246 #define N_BADMAG(x) \
247 (((x).fmagic)!=OMAGIC && ((x).fmagic)!=NMAGIC &&\
248 ((x).fmagic)!=FMAGIC && ((x).fmagic)!=IMAGIC)
249 #define NEWMAGIC FMAGIC
250 #else /* IRIS or IBMRTAIX or not USG */
251 static EXEC_HDR_TYPE hdr, ohdr;
252 #define NEWMAGIC ZMAGIC
253 #endif /* IRIS or IBMRTAIX not USG */
254 #endif /* not HPUX */
255
256 static int unexec_text_start;
257 static int unexec_data_start;
258
259 #endif /* not COFF */
260
261 static int pagemask;
262
263 /* Correct an int which is the bit pattern of a pointer to a byte
264 into an int which is the number of a byte.
265 This is a no-op on ordinary machines, but not on all. */
266
267 #ifndef ADDR_CORRECT /* Let m-*.h files override this definition */
268 #define ADDR_CORRECT(x) ((char *)(x) - (char*)0)
269 #endif
270
271 #ifdef emacs
272
273 static
report_error(file,fd)274 report_error (file, fd)
275 char *file;
276 int fd;
277 {
278 if (fd)
279 close (fd);
280 error ("Failure operating on %s", file);
281 }
282 #endif /* emacs */
283
284 #define ERROR0(msg) report_error_1 (new, msg, 0, 0); return -1
285 #define ERROR1(msg,x) report_error_1 (new, msg, x, 0); return -1
286 #define ERROR2(msg,x,y) report_error_1 (new, msg, x, y); return -1
287
288 static
report_error_1(fd,msg,a1,a2)289 report_error_1 (fd, msg, a1, a2)
290 int fd;
291 char *msg;
292 int a1, a2;
293 {
294 close (fd);
295 #ifdef emacs
296 error (msg, a1, a2);
297 #else
298 fprintf (stderr, msg, a1, a2);
299 fprintf (stderr, "\n");
300 #endif
301 }
302
303 /* ****************************************************************
304 * unexec
305 *
306 * driving logic.
307 */
unexec(new_name,a_name,data_start,bss_start,entry_address)308 unexec (new_name, a_name, data_start, bss_start, entry_address)
309 char *new_name, *a_name;
310 unsigned data_start, bss_start, entry_address;
311 {
312 int new, a_out = -1;
313
314 if (a_name && (a_out = open (a_name, 0)) < 0)
315 {
316 PERROR (a_name);
317 }
318 if ((new = creat (new_name, 0666)) < 0)
319 {
320 PERROR (new_name);
321 }
322
323 if (make_hdr (new, a_out, data_start, bss_start, entry_address, a_name, new_name) < 0
324 || copy_text_and_data (new, a_out) < 0
325 || copy_sym (new, a_out, a_name, new_name) < 0
326 #ifdef COFF
327 || adjust_lnnoptrs (new, a_out, new_name) < 0
328 #endif
329 )
330 {
331 close (new);
332 /* unlink (new_name); /* Failed, unlink new a.out */
333 return -1;
334 }
335
336 close (new);
337 if (a_out >= 0)
338 close (a_out);
339 mark_x (new_name);
340 return 0;
341 }
342
343 /* ****************************************************************
344 * make_hdr
345 *
346 * Make the header in the new a.out from the header in core.
347 * Modify the text and data sizes.
348 */
349 static int
make_hdr(new,a_out,data_start,bss_start,entry_address,a_name,new_name)350 make_hdr (new, a_out, data_start, bss_start, entry_address, a_name, new_name)
351 int new, a_out;
352 unsigned data_start, bss_start, entry_address;
353 char *a_name;
354 char *new_name;
355 {
356 int tem;
357 #ifdef COFF
358 auto struct scnhdr f_thdr; /* Text section header */
359 auto struct scnhdr f_dhdr; /* Data section header */
360 auto struct scnhdr f_bhdr; /* Bss section header */
361 auto struct scnhdr scntemp; /* Temporary section header */
362 register int scns;
363 #endif /* COFF */
364 #ifdef USG_SHARED_LIBRARIES
365 extern unsigned int bss_end;
366 #else
367 unsigned int bss_end;
368 #endif
369
370 pagemask = getpagesize () - 1;
371
372 /* Adjust text/data boundary. */
373 #ifdef NO_REMAP
374 data_start = (int) start_of_data ();
375 #else /* not NO_REMAP */
376 if (!data_start)
377 data_start = (int) start_of_data ();
378 #endif /* not NO_REMAP */
379 data_start = ADDR_CORRECT (data_start);
380
381 #ifdef SEGMENT_MASK
382 data_start = data_start & ~SEGMENT_MASK; /* (Down) to segment boundary. */
383 #else
384 data_start = data_start & ~pagemask; /* (Down) to page boundary. */
385 #endif
386
387 bss_end = ADDR_CORRECT (sbrk (0)) + pagemask;
388 bss_end &= ~ pagemask;
389
390 /* Adjust data/bss boundary. */
391 if (bss_start != 0)
392 {
393 bss_start = (ADDR_CORRECT (bss_start) + pagemask);
394 /* (Up) to page bdry. */
395 bss_start &= ~ pagemask;
396 if (bss_start > bss_end)
397 {
398 ERROR1 ("unexec: Specified bss_start (%u) is past end of program",
399 bss_start);
400 }
401 }
402 else
403 bss_start = bss_end;
404
405 if (data_start > bss_start) /* Can't have negative data size. */
406 {
407 ERROR2 ("unexec: data_start (%u) can't be greater than bss_start (%u)",
408 data_start, bss_start);
409 }
410
411 #ifdef COFF
412 /* Salvage as much info from the existing file as possible */
413 if (a_out >= 0)
414 {
415 if (read (a_out, &f_hdr, sizeof (f_hdr)) != sizeof (f_hdr))
416 {
417 PERROR (a_name);
418 }
419 block_copy_start += sizeof (f_hdr);
420 if (f_hdr.f_opthdr > 0)
421 {
422 if (read (a_out, &f_ohdr, sizeof (f_ohdr)) != sizeof (f_ohdr))
423 {
424 PERROR (a_name);
425 }
426 block_copy_start += sizeof (f_ohdr);
427 }
428 /* Loop through section headers, copying them in */
429 for (scns = f_hdr.f_nscns; scns > 0; scns--) {
430 if (read (a_out, &scntemp, sizeof (scntemp)) != sizeof (scntemp))
431 {
432 PERROR (a_name);
433 }
434 if (scntemp.s_scnptr > 0L)
435 {
436 if (block_copy_start < scntemp.s_scnptr + scntemp.s_size)
437 block_copy_start = scntemp.s_scnptr + scntemp.s_size;
438 }
439 if (strcmp (scntemp.s_name, ".text") == 0)
440 {
441 f_thdr = scntemp;
442 }
443 else if (strcmp (scntemp.s_name, ".data") == 0)
444 {
445 f_dhdr = scntemp;
446 }
447 else if (strcmp (scntemp.s_name, ".bss") == 0)
448 {
449 f_bhdr = scntemp;
450 }
451 }
452 }
453 else
454 {
455 ERROR0 ("can't build a COFF file from scratch yet");
456 }
457
458 /* Now we alter the contents of all the f_*hdr variables
459 to correspond to what we want to dump. */
460
461 #ifdef USG_SHARED_LIBRARIES
462
463 /* The amount of data we're adding to the file is distance from the
464 * end of the original .data space to the current end of the .data
465 * space.
466 */
467
468 bias = bss_end - (f_ohdr.data_start + f_dhdr.s_size);
469
470 #endif
471
472 f_hdr.f_flags |= (F_RELFLG | F_EXEC);
473 #ifdef EXEC_MAGIC
474 f_ohdr.magic = EXEC_MAGIC;
475 #endif
476 #ifndef NO_REMAP
477 f_ohdr.text_start = (long) start_of_text ();
478 f_ohdr.tsize = data_start - f_ohdr.text_start;
479 f_ohdr.data_start = data_start;
480 #endif /* NO_REMAP */
481 f_ohdr.dsize = bss_start - f_ohdr.data_start;
482 f_ohdr.bsize = bss_end - bss_start;
483 f_thdr.s_size = f_ohdr.tsize;
484 f_thdr.s_scnptr = sizeof (f_hdr) + sizeof (f_ohdr);
485 f_thdr.s_scnptr += (f_hdr.f_nscns) * (sizeof (f_thdr));
486 lnnoptr = f_thdr.s_lnnoptr;
487 #ifdef SECTION_ALIGNMENT
488 /* Some systems require special alignment
489 of the sections in the file itself. */
490 f_thdr.s_scnptr
491 = (f_thdr.s_scnptr + SECTION_ALIGNMENT) & ~SECTION_ALIGNMENT;
492 #endif /* SECTION_ALIGNMENT */
493 text_scnptr = f_thdr.s_scnptr;
494 f_dhdr.s_paddr = f_ohdr.data_start;
495 f_dhdr.s_vaddr = f_ohdr.data_start;
496 f_dhdr.s_size = f_ohdr.dsize;
497 f_dhdr.s_scnptr = f_thdr.s_scnptr + f_thdr.s_size;
498 #ifdef SECTION_ALIGNMENT
499 /* Some systems require special alignment
500 of the sections in the file itself. */
501 f_dhdr.s_scnptr
502 = (f_dhdr.s_scnptr + SECTION_ALIGNMENT) & ~SECTION_ALIGNMENT;
503 #endif /* SECTION_ALIGNMENT */
504 #ifdef DATA_SECTION_ALIGNMENT
505 /* Some systems require special alignment
506 of the data section only. */
507 f_dhdr.s_scnptr
508 = (f_dhdr.s_scnptr + DATA_SECTION_ALIGNMENT) & ~DATA_SECTION_ALIGNMENT;
509 #endif /* DATA_SECTION_ALIGNMENT */
510 data_scnptr = f_dhdr.s_scnptr;
511 f_bhdr.s_paddr = f_ohdr.data_start + f_ohdr.dsize;
512 f_bhdr.s_vaddr = f_ohdr.data_start + f_ohdr.dsize;
513 f_bhdr.s_size = f_ohdr.bsize;
514 f_bhdr.s_scnptr = 0L;
515 #ifndef USG_SHARED_LIBRARIES
516 bias = f_dhdr.s_scnptr + f_dhdr.s_size - block_copy_start;
517 #endif
518
519 if (f_hdr.f_symptr > 0L)
520 {
521 f_hdr.f_symptr += bias;
522 }
523
524 if (f_thdr.s_lnnoptr > 0L)
525 {
526 f_thdr.s_lnnoptr += bias;
527 }
528
529 #ifdef ADJUST_EXEC_HEADER
530 ADJUST_EXEC_HEADER
531 #endif /* ADJUST_EXEC_HEADER */
532
533 if (write (new, &f_hdr, sizeof (f_hdr)) != sizeof (f_hdr))
534 {
535 PERROR (new_name);
536 }
537
538 if (write (new, &f_ohdr, sizeof (f_ohdr)) != sizeof (f_ohdr))
539 {
540 PERROR (new_name);
541 }
542
543 #ifndef USG_SHARED_LIBRARIES
544
545 if (write (new, &f_thdr, sizeof (f_thdr)) != sizeof (f_thdr))
546 {
547 PERROR (new_name);
548 }
549
550 if (write (new, &f_dhdr, sizeof (f_dhdr)) != sizeof (f_dhdr))
551 {
552 PERROR (new_name);
553 }
554
555 if (write (new, &f_bhdr, sizeof (f_bhdr)) != sizeof (f_bhdr))
556 {
557 PERROR (new_name);
558 }
559
560 #else /* USG_SHARED_LIBRARIES */
561
562 /* The purpose of this code is to write out the new file's section
563 * header table.
564 *
565 * Scan through the original file's sections. If the encountered
566 * section is one we know (.text, .data or .bss), write out the
567 * correct header. If it is a section we do not know (such as
568 * .lib), adjust the address of where the section data is in the
569 * file, and write out the header.
570 *
571 * If any section preceeds .text or .data in the file, this code
572 * will not adjust the file pointer for that section correctly.
573 */
574
575 lseek (a_out, (off_t) sizeof (f_hdr) + sizeof (f_ohdr), 0);
576
577 for (scns = f_hdr.f_nscns; scns > 0; scns--)
578 {
579 if (read (a_out, &scntemp, sizeof (scntemp)) != sizeof (scntemp))
580 PERROR (a_name);
581
582 if (!strcmp (scntemp.s_name, f_thdr.s_name)) /* .text */
583 {
584 if (write (new, &f_thdr, sizeof (f_thdr)) != sizeof (f_thdr))
585 PERROR (new_name);
586 }
587 else if (!strcmp (scntemp.s_name, f_dhdr.s_name)) /* .data */
588 {
589 if (write (new, &f_dhdr, sizeof (f_dhdr)) != sizeof (f_dhdr))
590 PERROR (new_name);
591 }
592 else if (!strcmp (scntemp.s_name, f_bhdr.s_name)) /* .bss */
593 {
594 if (write (new, &f_bhdr, sizeof (f_bhdr)) != sizeof (f_bhdr))
595 PERROR (new_name);
596 }
597 else
598 {
599 if (scntemp.s_scnptr)
600 scntemp.s_scnptr += bias;
601 if (write (new, &scntemp, sizeof (scntemp)) != sizeof (scntemp))
602 PERROR (new_name);
603 }
604 }
605 #endif /* USG_SHARED_LIBRARIES */
606
607 return (0);
608
609 #else /* if not COFF */
610
611 /* Get symbol table info from header of a.out file if given one. */
612 if (a_out >= 0)
613 {
614 if (read (a_out, &ohdr, sizeof hdr) != sizeof hdr)
615 {
616 PERROR (a_name);
617 }
618
619 if (N_BADMAG (ohdr))
620 {
621 ERROR1 ("invalid magic number in %s", a_name);
622 }
623 hdr = ohdr;
624 }
625 else
626 {
627 bzero (hdr, sizeof hdr);
628 }
629
630 unexec_text_start = (long) start_of_text ();
631 unexec_data_start = data_start;
632
633 /* Machine-dependent fixup for header, or maybe for unexec_text_start */
634 #ifdef ADJUST_EXEC_HEADER
635 ADJUST_EXEC_HEADER;
636 #endif /* ADJUST_EXEC_HEADER */
637
638 hdr.a_trsize = 0;
639 hdr.a_drsize = 0;
640 if (entry_address != 0)
641 hdr.a_entry = entry_address;
642
643 hdr.a_bss = bss_end - bss_start;
644 hdr.a_data = bss_start - data_start;
645 #ifdef NO_REMAP
646 hdr.a_text = ohdr.a_text;
647 #else /* not NO_REMAP */
648 hdr.a_text = data_start - unexec_text_start;
649
650 #ifdef A_TEXT_OFFSET
651 hdr.a_text += A_TEXT_OFFSET (ohdr);
652 #endif
653
654 #endif /* not NO_REMAP */
655
656 if (write (new, &hdr, sizeof hdr) != sizeof hdr)
657 {
658 PERROR (new_name);
659 }
660
661 #ifdef A_TEXT_OFFSET
662 hdr.a_text -= A_TEXT_OFFSET (ohdr);
663 #endif
664
665 return 0;
666
667 #endif /* not COFF */
668 }
669
670 /* ****************************************************************
671 * copy_text_and_data
672 *
673 * Copy the text and data segments from memory to the new a.out
674 */
675 static int
copy_text_and_data(new,a_out)676 copy_text_and_data (new, a_out)
677 int new, a_out;
678 {
679 register char *end;
680 register char *ptr;
681
682 #ifdef COFF
683
684 #ifdef USG_SHARED_LIBRARIES
685
686 int scns;
687 struct scnhdr scntemp; /* Temporary section header */
688
689 /* The purpose of this code is to write out the new file's section
690 * contents.
691 *
692 * Step through the section table. If we know the section (.text,
693 * .data) do the appropriate thing. Otherwise, if the section has
694 * no allocated space in the file (.bss), do nothing. Otherwise,
695 * the section has space allocated in the file, and is not a section
696 * we know. So just copy it.
697 */
698
699 lseek (a_out, (off_t) sizeof (struct filehdr) + sizeof (struct aouthdr), 0);
700
701 for (scns = f_hdr.f_nscns; scns > 0; scns--)
702 {
703 if (read (a_out, &scntemp, sizeof (scntemp)) != sizeof (scntemp))
704 PERROR ("temacs");
705
706 if (!strcmp (scntemp.s_name, ".text"))
707 {
708 lseek (new, (off_t) text_scnptr, 0);
709 ptr = (char *) f_ohdr.text_start;
710 end = ptr + f_ohdr.tsize;
711 write_segment (new, ptr, end);
712 }
713 else if (!strcmp (scntemp.s_name, ".data"))
714 {
715 lseek (new, (off_t) data_scnptr, 0);
716 ptr = (char *) f_ohdr.data_start;
717 end = ptr + f_ohdr.dsize;
718 write_segment (new, ptr, end);
719 }
720 else if (!scntemp.s_scnptr)
721 ; /* do nothing - no data for this section */
722 else
723 {
724 char page[BUFSIZ];
725 int size, n;
726 long old_a_out_ptr = lseek (a_out, (off_t) 0, 1);
727
728 lseek (a_out, (off_t) scntemp.s_scnptr, 0);
729 for (size = scntemp.s_size; size > 0; size -= sizeof (page))
730 {
731 n = size > sizeof (page) ? sizeof (page) : size;
732 if (read (a_out, page, n) != n || write (new, page, n) != n)
733 PERROR ("xemacs");
734 }
735 lseek (a_out, (off_t) old_a_out_ptr, 0);
736 }
737 }
738
739 #else /* COFF, but not USG_SHARED_LIBRARIES */
740
741 lseek (new, (off_t) text_scnptr, 0);
742 ptr = (char *) f_ohdr.text_start;
743 end = ptr + f_ohdr.tsize;
744 write_segment (new, ptr, end);
745
746 lseek (new, (off_t) data_scnptr, 0);
747 ptr = (char *) f_ohdr.data_start;
748 end = ptr + f_ohdr.dsize;
749 write_segment (new, ptr, end);
750
751 #endif /* USG_SHARED_LIBRARIES */
752
753 #else /* if not COFF */
754
755 /* Some machines count the header as part of the text segment.
756 That is to say, the header appears in core
757 just before the address that start_of_text () returns.
758 For them, N_TXTOFF is the place where the header goes.
759 We must adjust the seek to the place after the header.
760 Note that at this point hdr.a_text does *not* count
761 the extra A_TEXT_OFFSET bytes, only the actual bytes of code. */
762
763 #ifdef A_TEXT_SEEK
764 lseek (new, (off_t) A_TEXT_SEEK (hdr), 0);
765 #else
766 #ifdef A_TEXT_OFFSET
767 /* Note that on the Sequent machine A_TEXT_OFFSET != sizeof (hdr)
768 and sizeof (hdr) is the correct amount to add here. */
769 /* In version 19, eliminate this case and use A_TEXT_SEEK whenever
770 N_TXTOFF is not right. */
771 lseek (new, (off_t) N_TXTOFF (hdr) + sizeof (hdr), 0);
772 #else
773 lseek (new, (off_t) N_TXTOFF (hdr), 0);
774 #endif /* no A_TEXT_OFFSET */
775 #endif /* no A_TEXT_SEEK */
776
777 ptr = (char *) unexec_text_start;
778 end = ptr + hdr.a_text;
779 write_segment (new, ptr, end);
780
781 ptr = (char *) unexec_data_start;
782 end = ptr + hdr.a_data;
783 /* This lseek is certainly incorrect when A_TEXT_OFFSET
784 and I believe it is a no-op otherwise.
785 Let's see if its absence ever fails. */
786 /* lseek (new, (off_t) N_TXTOFF (hdr) + hdr.a_text, 0); */
787 write_segment (new, ptr, end);
788
789 #endif /* not COFF */
790
791 return 0;
792 }
793
write_segment(new,ptr,end)794 write_segment (new, ptr, end)
795 int new;
796 register char *ptr, *end;
797 {
798 register int i, nwrite, ret;
799 char buf[80];
800 extern int errno;
801 char zeros[128];
802
803 bzero (zeros, sizeof zeros);
804
805 for (i = 0; ptr < end;)
806 {
807 /* distance to next multiple of 128. */
808 nwrite = (((int) ptr + 128) & -128) - (int) ptr;
809 /* But not beyond specified end. */
810 if (nwrite > end - ptr) nwrite = end - ptr;
811 ret = write (new, ptr, nwrite);
812 /* If write gets a page fault, it means we reached
813 a gap between the old text segment and the old data segment.
814 This gap has probably been remapped into part of the text segment.
815 So write zeros for it. */
816 if (ret == -1 && errno == EFAULT)
817 write (new, zeros, nwrite);
818 else if (nwrite != ret)
819 {
820 sprintf (buf,
821 "unexec write failure: addr 0x%x, fileno %d, size 0x%x, wrote 0x%x, errno %d",
822 ptr, new, nwrite, ret, errno);
823 PERROR (buf);
824 }
825 i += nwrite;
826 ptr += nwrite;
827 }
828 }
829
830 /* ****************************************************************
831 * copy_sym
832 *
833 * Copy the relocation information and symbol table from the a.out to the new
834 */
835 static int
copy_sym(new,a_out,a_name,new_name)836 copy_sym (new, a_out, a_name, new_name)
837 int new, a_out;
838 char *a_name, *new_name;
839 {
840 char page[1024];
841 int n;
842
843 if (a_out < 0)
844 return 0;
845
846 #ifdef COFF
847 if (SYMS_START == 0L)
848 return 0;
849 #endif /* COFF */
850
851 #ifdef COFF
852 if (lnnoptr) /* if there is line number info */
853 lseek (a_out, (off_t) lnnoptr, 0); /* start copying from there */
854 else
855 #endif /* COFF */
856 lseek (a_out, (off_t) SYMS_START, 0); /* Position a.out to symtab. */
857
858 while ((n = read (a_out, page, sizeof page)) > 0)
859 {
860 if (write (new, page, n) != n)
861 {
862 PERROR (new_name);
863 }
864 }
865 if (n < 0)
866 {
867 PERROR (a_name);
868 }
869 return 0;
870 }
871
872 /* ****************************************************************
873 * mark_x
874 *
875 * After succesfully building the new a.out, mark it executable
876 */
877 static
mark_x(name)878 mark_x (name)
879 char *name;
880 {
881 struct stat sbuf;
882 int um;
883 int new = 0; /* for PERROR */
884
885 um = umask (777);
886 umask (um);
887 if (stat (name, &sbuf) == -1)
888 {
889 PERROR (name);
890 }
891 sbuf.st_mode |= 0111 & ~um;
892 if (chmod (name, sbuf.st_mode) == -1)
893 PERROR (name);
894 }
895
896 /*
897 * If the COFF file contains a symbol table and a line number section,
898 * then any auxiliary entries that have values for x_lnnoptr must
899 * be adjusted by the amount that the line number section has moved
900 * in the file (bias computed in make_hdr). The #@$%&* designers of
901 * the auxiliary entry structures used the absolute file offsets for
902 * the line number entry rather than an offset from the start of the
903 * line number section!
904 *
905 * When I figure out how to scan through the symbol table and pick out
906 * the auxiliary entries that need adjustment, this routine will
907 * be fixed. As it is now, all such entries are wrong and sdb
908 * will complain. Fred Fish, UniSoft Systems Inc.
909 */
910
911 #ifdef COFF
912
913 /* This function is probably very slow. Instead of reopening the new
914 file for input and output it should copy from the old to the new
915 using the two descriptors already open (WRITEDESC and READDESC).
916 Instead of reading one small structure at a time it should use
917 a reasonable size buffer. But I don't have time to work on such
918 things, so I am installing it as submitted to me. -- RMS. */
919
adjust_lnnoptrs(writedesc,readdesc,new_name)920 adjust_lnnoptrs (writedesc, readdesc, new_name)
921 int writedesc;
922 int readdesc;
923 char *new_name;
924 {
925 register int nsyms;
926 register int new;
927 #ifdef amdahl_uts
928 SYMENT symentry;
929 AUXENT auxentry;
930 #else
931 struct syment symentry;
932 union auxent auxentry;
933 #endif
934
935 if (!lnnoptr || !f_hdr.f_symptr)
936 return 0;
937
938 if ((new = open (new_name, 2)) < 0)
939 {
940 PERROR (new_name);
941 return -1;
942 }
943
944 lseek (new, (off_t) f_hdr.f_symptr, 0);
945 for (nsyms = 0; nsyms < f_hdr.f_nsyms; nsyms++)
946 {
947 read (new, &symentry, SYMESZ);
948 if (symentry.n_numaux)
949 {
950 read (new, &auxentry, AUXESZ);
951 nsyms++;
952 if (ISFCN (symentry.n_type)) {
953 auxentry.x_sym.x_fcnary.x_fcn.x_lnnoptr += bias;
954 lseek (new, (off_t) -AUXESZ, 1);
955 write (new, &auxentry, AUXESZ);
956 }
957 }
958 }
959 close (new);
960 }
961
962 #endif /* COFF */
963
964 #endif /* not CANNOT_UNEXEC */
965
966 #endif /* not CANNOT_DUMP */
967