1 /* Dump an executable image.
2 Copyright (C) 1985, 1986, 1987, 1988 Free Software Foundation, Inc.
4 This file is part of XEmacs.
6 XEmacs is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option) any
11 XEmacs is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with XEmacs; see the file COPYING. If not, write to
18 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
21 /* Synched up with: FSF 20.2. */
23 /* Originally based on the COFF unexec.c by Spencer W. Thomas.
25 * Subsequently hacked on by
26 * Bill Mann <Bill_Man@praxisint.com>
27 * Andrew Vignaux <Andrew.Vignaux@comp.vuw.ac.nz>
28 * Mike Sperber <sperber@informatik.uni-tuebingen.de>
31 * unexec (new_name, a_name, data_start, bss_start, entry_address)
32 * char *new_name, *a_name;
33 * unsigned data_start, bss_start, entry_address;
35 * Takes a snapshot of the program and makes an a.out format file in the
36 * file named by the string argument new_name.
37 * If a_name is non-NULL, the symbol table will be taken from the given file.
38 * On some machines, an existing a_name file is required.
40 * data_start and entry_address are ignored.
42 * bss_start indicates how much of the data segment is to be saved in the
43 * a.out file and restored when the program is executed. It gives the lowest
44 * unsaved address, and is rounded up to a page boundary. The default when 0
45 * is given assumes that the entire data segment is to be stored, including
46 * the previous data and bss as well as any additional storage allocated with
52 #define PERROR(arg) perror (arg); return -1
55 #define PERROR(file) report_error (file, new)
59 /* Define getpagesize () if the system does not.
60 Note that this may depend on symbols defined in a.out.h
62 #include "getpagesize.h"
64 #include <sys/types.h>
71 extern char *start_of_text (void); /* Start of text */
72 extern char *start_of_data (void); /* Start of initialized data */
82 static struct filehdr f_hdr; /* File header */
83 static struct aouthdr f_ohdr; /* Optional file header (a.out) */
84 static long bias; /* Bias to add for growth */
85 static long lnnoptr; /* Pointer to line-number info within file */
87 static long text_scnptr;
88 static long data_scnptr;
89 #define ALIGN(val, pwr) (((val) + ((1L<<(pwr))-1)) & ~((1L<<(pwr))-1))
90 static long load_scnptr;
91 static long orig_load_scnptr;
92 static long orig_data_scnptr;
93 static int unrelocate_symbols (int, int, char *, char *);
96 #define MAX_SECTIONS 10
99 static int adjust_lnnoptrs (int, int, char *);
103 /* Correct an int which is the bit pattern of a pointer to a byte
104 into an int which is the number of a byte.
105 This is a no-op on ordinary machines, but not on all. */
107 #ifndef ADDR_CORRECT /* Let m-*.h files override this definition */
108 #define ADDR_CORRECT(x) ((char *)(x) - (char*)0)
115 report_error (char *file, int fd)
119 report_file_error ("Cannot unexec", Fcons (build_string (file), Qnil));
123 #define ERROR0(msg) report_error_1 (new, msg, 0, 0); return -1
124 #define ERROR1(msg,x) report_error_1 (new, msg, x, 0); return -1
125 #define ERROR2(msg,x,y) report_error_1 (new, msg, x, y); return -1
128 report_error_1 (int fd, char *msg, int a1, int a2)
134 fprintf (stderr, msg, a1, a2);
135 fprintf (stderr, "\n");
139 static int make_hdr (int, int, unsigned, unsigned, unsigned, char *, char *);
140 static void mark_x (char *);
141 static int copy_text_and_data (int);
142 static int copy_sym (int, int, char *, char *);
143 static void write_segment (int, char *, char *);
145 /* ****************************************************************
150 int unexec (char *new_name, char *a_name,
151 uintptr_t data_start,
153 uintptr_t entry_address)
155 int new = -1, a_out = -1;
157 if (a_name && (a_out = open (a_name, O_RDONLY)) < 0)
161 if ((new = creat (new_name, 0666)) < 0)
165 if (make_hdr (new, a_out,
166 data_start, bss_start,
168 a_name, new_name) < 0
169 || copy_text_and_data (new) < 0
170 || copy_sym (new, a_out, a_name, new_name) < 0
171 || adjust_lnnoptrs (new, a_out, new_name) < 0
172 || unrelocate_symbols (new, a_out, a_name, new_name) < 0)
185 /* ****************************************************************
188 * Make the header in the new a.out from the header in core.
189 * Modify the text and data sizes.
192 make_hdr (int new, int a_out,
193 unsigned data_start, unsigned bss_start,
194 unsigned entry_address,
195 char *a_name, char *new_name)
198 unsigned int bss_end;
200 struct scnhdr section[MAX_SECTIONS];
201 struct scnhdr * f_thdr; /* Text section header */
202 struct scnhdr * f_dhdr; /* Data section header */
203 struct scnhdr * f_bhdr; /* Bss section header */
204 struct scnhdr * f_lhdr; /* Loader section header */
205 struct scnhdr * f_tchdr; /* Typechk section header */
206 struct scnhdr * f_dbhdr; /* Debug section header */
207 struct scnhdr * f_xhdr; /* Except section header */
209 load_scnptr = orig_load_scnptr = lnnoptr = 0;
210 pagemask = getpagesize () - 1;
212 /* Adjust text/data boundary. */
213 data_start = (long) start_of_data ();
214 data_start = ADDR_CORRECT (data_start);
216 data_start = data_start & ~pagemask; /* (Down) to page boundary. */
218 bss_end = ADDR_CORRECT (sbrk (0)) + pagemask;
219 bss_end &= ~ pagemask;
220 /* Adjust data/bss boundary. */
223 bss_start = (ADDR_CORRECT (bss_start) + pagemask);
224 /* (Up) to page bdry. */
225 bss_start &= ~ pagemask;
226 if (bss_start > bss_end)
228 ERROR1 ("unexec: Specified bss_start (%u) is past end of program",
235 if (data_start > bss_start) /* Can't have negative data size. */
237 ERROR2 ("unexec: data_start (%u) can't be greater than bss_start (%u)",
238 data_start, bss_start);
241 /* Salvage as much info from the existing file as possible */
242 f_thdr = NULL; f_dhdr = NULL; f_bhdr = NULL;
243 f_lhdr = NULL; f_tchdr = NULL; f_dbhdr = NULL; f_xhdr = NULL;
246 if (read (a_out, &f_hdr, sizeof (f_hdr)) != sizeof (f_hdr))
250 if (f_hdr.f_opthdr > 0)
252 if (read (a_out, &f_ohdr, sizeof (f_ohdr)) != sizeof (f_ohdr))
257 if (f_hdr.f_nscns > MAX_SECTIONS)
259 ERROR0 ("unexec: too many section headers -- increase MAX_SECTIONS");
261 /* Loop through section headers */
262 for (scns = 0; scns < f_hdr.f_nscns; scns++) {
263 struct scnhdr *s = §ion[scns];
264 if (read (a_out, s, sizeof (*s)) != sizeof (*s))
269 #define CHECK_SCNHDR(ptr, name, flags) \
270 if (strcmp(s->s_name, name) == 0) { \
271 if (s->s_flags != flags) { \
272 fprintf(stderr, "unexec: %lx flags where %x expected in %s section.\n", \
273 (unsigned long)s->s_flags, flags, name); \
276 fprintf(stderr, "unexec: duplicate section header for section %s.\n", \
281 CHECK_SCNHDR(f_thdr, _TEXT, STYP_TEXT);
282 CHECK_SCNHDR(f_dhdr, _DATA, STYP_DATA);
283 CHECK_SCNHDR(f_bhdr, _BSS, STYP_BSS);
284 CHECK_SCNHDR(f_lhdr, _LOADER, STYP_LOADER);
285 CHECK_SCNHDR(f_dbhdr, _DEBUG, STYP_DEBUG);
286 CHECK_SCNHDR(f_tchdr, _TYPCHK, STYP_TYPCHK);
287 CHECK_SCNHDR(f_xhdr, _EXCEPT, STYP_EXCEPT);
292 ERROR1 ("unexec: couldn't find \"%s\" section", (int) _TEXT);
296 ERROR1 ("unexec: couldn't find \"%s\" section", (int) _DATA);
300 ERROR1 ("unexec: couldn't find \"%s\" section", (int) _BSS);
305 ERROR0 ("can't build a COFF file from scratch yet");
307 orig_data_scnptr = f_dhdr->s_scnptr;
308 orig_load_scnptr = f_lhdr ? f_lhdr->s_scnptr : 0;
310 /* Now we alter the contents of all the f_*hdr variables
311 to correspond to what we want to dump. */
313 /* Indicate that the reloc information is no longer valid for ld (bind);
314 we only update it enough to fake out the exec-time loader. */
315 f_hdr.f_flags |= (F_RELFLG | F_EXEC);
317 f_ohdr.dsize = bss_start - f_ohdr.data_start;
318 f_ohdr.bsize = bss_end - bss_start;
320 f_dhdr->s_size = f_ohdr.dsize;
321 f_bhdr->s_size = f_ohdr.bsize;
322 f_bhdr->s_paddr = f_ohdr.data_start + f_ohdr.dsize;
323 f_bhdr->s_vaddr = f_ohdr.data_start + f_ohdr.dsize;
327 ulong ptr = section[0].s_scnptr;
330 for (scns = 0; scns < f_hdr.f_nscns; scns++)
332 struct scnhdr *s = §ion[scns];
334 if (s->s_flags & STYP_PAD) /* .pad sections omitted in AIX 4.1 */
337 * the text_start should probably be o_algntext but that doesn't
340 if (f_ohdr.text_start != 0) /* && scns != 0 */
342 s->s_size = 512 - (ptr % 512);
343 if (s->s_size == 512)
348 else if (s->s_flags & STYP_DATA)
350 else if (!(s->s_flags & (STYP_TEXT | STYP_BSS)))
352 if (bias == -1) /* if first section after bss */
353 bias = ptr - s->s_scnptr;
359 ptr = ptr + s->s_size;
363 /* fix other pointers */
364 for (scns = 0; scns < f_hdr.f_nscns; scns++)
366 struct scnhdr *s = §ion[scns];
368 if (s->s_relptr != 0)
372 if (s->s_lnnoptr != 0)
374 if (lnnoptr == 0) lnnoptr = s->s_lnnoptr;
375 s->s_lnnoptr += bias;
379 if (f_hdr.f_symptr > 0L)
381 f_hdr.f_symptr += bias;
384 text_scnptr = f_thdr->s_scnptr;
385 data_scnptr = f_dhdr->s_scnptr;
386 load_scnptr = f_lhdr ? f_lhdr->s_scnptr : 0;
388 if (write (new, &f_hdr, sizeof (f_hdr)) != sizeof (f_hdr))
393 if (f_hdr.f_opthdr > 0)
395 if (write (new, &f_ohdr, sizeof (f_ohdr)) != sizeof (f_ohdr))
401 for (scns = 0; scns < f_hdr.f_nscns; scns++) {
402 struct scnhdr *s = §ion[scns];
403 if (write (new, s, sizeof (*s)) != sizeof (*s))
412 /* ****************************************************************
415 * Copy the text and data segments from memory to the new a.out
418 copy_text_and_data (int new)
423 lseek (new, (long) text_scnptr, SEEK_SET);
424 ptr = start_of_text () + text_scnptr;
425 end = ptr + f_ohdr.tsize;
426 write_segment (new, ptr, end);
428 lseek (new, (long) data_scnptr, SEEK_SET);
429 ptr = (char *) f_ohdr.data_start;
430 end = ptr + f_ohdr.dsize;
431 write_segment (new, ptr, end);
436 #define UnexBlockSz (1<<12) /* read/write block size */
438 write_segment (int new, char *ptr, char *end)
442 char zeros[UnexBlockSz];
444 for (i = 0; ptr < end;)
446 /* distance to next block. */
447 nwrite = (((int) ptr + UnexBlockSz) & -UnexBlockSz) - (int) ptr;
448 /* But not beyond specified end. */
449 if (nwrite > end - ptr) nwrite = end - ptr;
450 ret = write (new, ptr, nwrite);
451 /* If write gets a page fault, it means we reached
452 a gap between the old text segment and the old data segment.
453 This gap has probably been remapped into part of the text segment.
454 So write zeros for it. */
455 if (ret == -1 && errno == EFAULT)
457 memset (zeros, 0, nwrite);
458 write (new, zeros, nwrite);
460 else if (nwrite != ret)
463 "unexec write failure: addr 0x%lx, fileno %d, size 0x%x, wrote 0x%x, errno %d",
464 (unsigned long)ptr, new, nwrite, ret, errno);
472 /* ****************************************************************
475 * Copy the relocation information and symbol table from the a.out to the new
478 copy_sym (int new, int a_out, char *a_name, char *new_name)
480 char page[UnexBlockSz];
486 if (orig_load_scnptr == 0L)
489 if (lnnoptr && lnnoptr < orig_load_scnptr) /* if there is line number info */
490 lseek (a_out, lnnoptr, SEEK_SET); /* start copying from there */
492 lseek (a_out, orig_load_scnptr, SEEK_SET); /* Position a.out to symtab. */
494 while ((n = read (a_out, page, sizeof page)) > 0)
496 if (write (new, page, n) != n)
508 /* ****************************************************************
511 * After successfully building the new a.out, mark it executable
518 int new = 0; /* for PERROR */
522 if (stat (name, &sbuf) == -1)
526 sbuf.st_mode |= 0111 & ~um;
527 if (chmod (name, sbuf.st_mode) == -1)
532 adjust_lnnoptrs (int writedesc, int readdesc, char *new_name)
537 struct syment symentry;
538 union auxent auxentry;
540 if (!lnnoptr || !f_hdr.f_symptr)
543 if ((new = open (new_name, O_RDWR)) < 0)
549 lseek (new, f_hdr.f_symptr, SEEK_SET);
550 for (nsyms = 0; nsyms < f_hdr.f_nsyms; nsyms++)
552 read (new, &symentry, SYMESZ);
553 if (symentry.n_sclass == C_BINCL || symentry.n_sclass == C_EINCL)
555 symentry.n_value += bias;
556 lseek (new, -SYMESZ, SEEK_CUR);
557 write (new, &symentry, SYMESZ);
560 for (naux = symentry.n_numaux; naux-- != 0; )
562 read (new, &auxentry, AUXESZ);
564 if (naux != 0 /* skip csect auxentry (last entry) */
565 && (symentry.n_sclass == C_EXT || symentry.n_sclass == C_HIDEXT))
567 auxentry.x_sym.x_fcnary.x_fcn.x_lnnoptr += bias;
568 lseek (new, -AUXESZ, SEEK_CUR);
569 write (new, &auxentry, AUXESZ);
579 unrelocate_symbols (int new, int a_out, char *a_name, char *new_name)
584 ulong t_reloc = (ulong) &_text - f_ohdr.text_start;
585 #ifndef ALIGN_DATA_RELOC
586 ulong d_reloc = (ulong) &_data - f_ohdr.data_start;
588 /* This worked (and was needed) before AIX 4.2.
589 I have no idea why. -- Mike */
590 ulong d_reloc = (ulong) &_data - ALIGN(f_ohdr.data_start, 2);
594 if (load_scnptr == 0)
597 lseek (a_out, orig_load_scnptr, SEEK_SET);
598 if (read (a_out, &ldhdr, sizeof (ldhdr)) != sizeof (ldhdr))
603 #define SYMNDX_TEXT 0
604 #define SYMNDX_DATA 1
607 for (i = 0; i < ldhdr.l_nreloc; i++)
610 orig_load_scnptr + LDHDRSZ + LDSYMSZ*ldhdr.l_nsyms + LDRELSZ*i,
613 if (read (a_out, &ldrel, LDRELSZ) != LDRELSZ)
618 /* move the BSS loader symbols to the DATA segment */
619 if (ldrel.l_symndx == SYMNDX_BSS)
621 ldrel.l_symndx = SYMNDX_DATA;
624 load_scnptr + LDHDRSZ + LDSYMSZ*ldhdr.l_nsyms + LDRELSZ*i,
627 if (write (new, &ldrel, LDRELSZ) != LDRELSZ)
633 if (ldrel.l_rsecnm == f_ohdr.o_sndata)
638 orig_data_scnptr + (ldrel.l_vaddr - f_ohdr.data_start),
641 if (read (a_out, (void *) &orig_int, sizeof (orig_int))
642 != sizeof (orig_int))
647 p = (int *) (ldrel.l_vaddr + d_reloc);
649 switch (ldrel.l_symndx) {
651 orig_int = * p - t_reloc;
656 orig_int = * p - d_reloc;
663 data_scnptr + (ldrel.l_vaddr - f_ohdr.data_start),
665 if (write (new, (void *) &orig_int, sizeof (orig_int))
666 != sizeof (orig_int))