]>
code.delx.au - gnu-emacs/blob - src/unexaix.c
1 /* Dump an executable image.
2 Copyright (C) 1985-1988, 1999, 2001-2013 Free Software Foundation,
5 This file is part of GNU Emacs.
7 GNU Emacs is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation, either version 3 of the License, or
10 (at your option) any later version.
12 GNU Emacs is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
21 In other words, you are welcome to use, share and improve this program.
22 You are forbidden to forbid anyone else to use, share and improve
23 what you give them. Help stamp out software-hoarding! */
26 /* Originally based on the COFF unexec.c by Spencer W. Thomas.
28 * Subsequently hacked on by
29 * Bill Mann <Bill_Man@praxisint.com>
30 * Andrew Vignaux <Andrew.Vignaux@comp.vuw.ac.nz>
31 * Mike Sperber <sperber@informatik.uni-tuebingen.de>
34 * unexec (const char *new_name, const *old_name);
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.
46 #define PERROR(file) report_error (file, new)
48 /* Define getpagesize () if the system does not.
49 Note that this may depend on symbols defined in a.out.h
51 #include "getpagesize.h"
53 #include <sys/types.h>
60 #include "mem-limits.h"
62 char *start_of_text (void); /* Start of text */
72 static struct filehdr f_hdr
; /* File header */
73 static struct aouthdr f_ohdr
; /* Optional file header (a.out) */
74 static long bias
; /* Bias to add for growth */
75 static long lnnoptr
; /* Pointer to line-number info within file */
77 static long text_scnptr
;
78 static long data_scnptr
;
79 #define ALIGN(val, pwr) (((val) + ((1L<<(pwr))-1)) & ~((1L<<(pwr))-1))
80 static long load_scnptr
;
81 static long orig_load_scnptr
;
82 static long orig_data_scnptr
;
83 static int unrelocate_symbols (int, int, const char *, const char *);
86 #define MAX_SECTIONS 10
89 static int adjust_lnnoptrs (int, int, const char *);
96 report_error (const char *file
, int fd
)
100 report_file_error ("Cannot unexec", Fcons (build_string (file
), Qnil
));
103 #define ERROR0(msg) report_error_1 (new, msg, 0, 0); return -1
104 #define ERROR1(msg,x) report_error_1 (new, msg, x, 0); return -1
105 #define ERROR2(msg,x,y) report_error_1 (new, msg, x, y); return -1
108 #define ADDR_CORRECT(x) ((int)(x))
111 report_error_1 (int fd
, const char *msg
, int a1
, int a2
)
117 static int make_hdr (int, int, const char *, const char *);
118 static void mark_x (const char *);
119 static int copy_text_and_data (int);
120 static int copy_sym (int, int, const char *, const char *);
121 static void write_segment (int, char *, char *);
123 /* ****************************************************************
129 unexec (const char *new_name
, const char *a_name
)
131 int new = -1, a_out
= -1;
133 if (a_name
&& (a_out
= open (a_name
, O_RDONLY
)) < 0)
137 if ((new = creat (new_name
, 0666)) < 0)
141 if (make_hdr (new, a_out
,
142 a_name
, new_name
) < 0
143 || copy_text_and_data (new) < 0
144 || copy_sym (new, a_out
, a_name
, new_name
) < 0
145 || adjust_lnnoptrs (new, a_out
, new_name
) < 0
146 || unrelocate_symbols (new, a_out
, a_name
, new_name
) < 0)
158 /* ****************************************************************
161 * Make the header in the new a.out from the header in core.
162 * Modify the text and data sizes.
165 make_hdr (int new, int a_out
,
166 const char *a_name
, const char *new_name
)
169 unsigned int bss_start
;
170 unsigned int data_start
;
172 struct scnhdr section
[MAX_SECTIONS
];
173 struct scnhdr
* f_thdr
; /* Text section header */
174 struct scnhdr
* f_dhdr
; /* Data section header */
175 struct scnhdr
* f_bhdr
; /* Bss section header */
176 struct scnhdr
* f_lhdr
; /* Loader section header */
177 struct scnhdr
* f_tchdr
; /* Typechk section header */
178 struct scnhdr
* f_dbhdr
; /* Debug section header */
179 struct scnhdr
* f_xhdr
; /* Except section header */
181 load_scnptr
= orig_load_scnptr
= lnnoptr
= 0;
182 pagemask
= getpagesize () - 1;
184 /* Adjust text/data boundary. */
185 data_start
= (long) start_of_data ();
186 data_start
= ADDR_CORRECT (data_start
);
188 data_start
= data_start
& ~pagemask
; /* (Down) to page boundary. */
190 bss_start
= ADDR_CORRECT (sbrk (0)) + pagemask
;
191 bss_start
&= ~ pagemask
;
193 if (data_start
> bss_start
) /* Can't have negative data size. */
195 ERROR2 ("unexec: data_start (%u) can't be greater than bss_start (%u)",
196 data_start
, bss_start
);
199 /* Salvage as much info from the existing file as possible */
200 f_thdr
= NULL
; f_dhdr
= NULL
; f_bhdr
= NULL
;
201 f_lhdr
= NULL
; f_tchdr
= NULL
; f_dbhdr
= NULL
; f_xhdr
= NULL
;
204 if (read (a_out
, &f_hdr
, sizeof (f_hdr
)) != sizeof (f_hdr
))
208 if (f_hdr
.f_opthdr
> 0)
210 if (read (a_out
, &f_ohdr
, sizeof (f_ohdr
)) != sizeof (f_ohdr
))
215 if (f_hdr
.f_nscns
> MAX_SECTIONS
)
217 ERROR0 ("unexec: too many section headers -- increase MAX_SECTIONS");
219 /* Loop through section headers */
220 for (scns
= 0; scns
< f_hdr
.f_nscns
; scns
++) {
221 struct scnhdr
*s
= §ion
[scns
];
222 if (read (a_out
, s
, sizeof (*s
)) != sizeof (*s
))
227 #define CHECK_SCNHDR(ptr, name, flags) \
228 if (strcmp (s->s_name, name) == 0) { \
229 if (s->s_flags != flags) { \
230 fprintf (stderr, "unexec: %lx flags where %x expected in %s section.\n", \
231 (unsigned long)s->s_flags, flags, name); \
234 fprintf (stderr, "unexec: duplicate section header for section %s.\n", \
239 CHECK_SCNHDR (f_thdr
, _TEXT
, STYP_TEXT
);
240 CHECK_SCNHDR (f_dhdr
, _DATA
, STYP_DATA
);
241 CHECK_SCNHDR (f_bhdr
, _BSS
, STYP_BSS
);
242 CHECK_SCNHDR (f_lhdr
, _LOADER
, STYP_LOADER
);
243 CHECK_SCNHDR (f_dbhdr
, _DEBUG
, STYP_DEBUG
);
244 CHECK_SCNHDR (f_tchdr
, _TYPCHK
, STYP_TYPCHK
);
245 CHECK_SCNHDR (f_xhdr
, _EXCEPT
, STYP_EXCEPT
);
250 ERROR1 ("unexec: couldn't find \"%s\" section", (int) _TEXT
);
254 ERROR1 ("unexec: couldn't find \"%s\" section", (int) _DATA
);
258 ERROR1 ("unexec: couldn't find \"%s\" section", (int) _BSS
);
263 ERROR0 ("can't build a COFF file from scratch yet");
265 orig_data_scnptr
= f_dhdr
->s_scnptr
;
266 orig_load_scnptr
= f_lhdr
? f_lhdr
->s_scnptr
: 0;
268 /* Now we alter the contents of all the f_*hdr variables
269 to correspond to what we want to dump. */
271 /* Indicate that the reloc information is no longer valid for ld (bind);
272 we only update it enough to fake out the exec-time loader. */
273 f_hdr
.f_flags
|= (F_RELFLG
| F_EXEC
);
275 f_ohdr
.dsize
= bss_start
- f_ohdr
.data_start
;
278 f_dhdr
->s_size
= f_ohdr
.dsize
;
279 f_bhdr
->s_size
= f_ohdr
.bsize
;
280 f_bhdr
->s_paddr
= f_ohdr
.data_start
+ f_ohdr
.dsize
;
281 f_bhdr
->s_vaddr
= f_ohdr
.data_start
+ f_ohdr
.dsize
;
285 ulong ptr
= section
[0].s_scnptr
;
288 for (scns
= 0; scns
< f_hdr
.f_nscns
; scns
++)
290 struct scnhdr
*s
= §ion
[scns
];
292 if (s
->s_flags
& STYP_PAD
) /* .pad sections omitted in AIX 4.1 */
295 * the text_start should probably be o_algntext but that doesn't
298 if (f_ohdr
.text_start
!= 0) /* && scns != 0 */
300 s
->s_size
= 512 - (ptr
% 512);
301 if (s
->s_size
== 512)
306 else if (s
->s_flags
& STYP_DATA
)
308 else if (!(s
->s_flags
& (STYP_TEXT
| STYP_BSS
)))
310 if (bias
== -1) /* if first section after bss */
311 bias
= ptr
- s
->s_scnptr
;
317 ptr
= ptr
+ s
->s_size
;
321 /* fix other pointers */
322 for (scns
= 0; scns
< f_hdr
.f_nscns
; scns
++)
324 struct scnhdr
*s
= §ion
[scns
];
326 if (s
->s_relptr
!= 0)
330 if (s
->s_lnnoptr
!= 0)
332 if (lnnoptr
== 0) lnnoptr
= s
->s_lnnoptr
;
333 s
->s_lnnoptr
+= bias
;
337 if (f_hdr
.f_symptr
> 0L)
339 f_hdr
.f_symptr
+= bias
;
342 text_scnptr
= f_thdr
->s_scnptr
;
343 data_scnptr
= f_dhdr
->s_scnptr
;
344 load_scnptr
= f_lhdr
? f_lhdr
->s_scnptr
: 0;
346 if (write (new, &f_hdr
, sizeof (f_hdr
)) != sizeof (f_hdr
))
351 if (f_hdr
.f_opthdr
> 0)
353 if (write (new, &f_ohdr
, sizeof (f_ohdr
)) != sizeof (f_ohdr
))
359 for (scns
= 0; scns
< f_hdr
.f_nscns
; scns
++) {
360 struct scnhdr
*s
= §ion
[scns
];
361 if (write (new, s
, sizeof (*s
)) != sizeof (*s
))
370 /* ****************************************************************
373 * Copy the text and data segments from memory to the new a.out
376 copy_text_and_data (int new)
381 lseek (new, (long) text_scnptr
, SEEK_SET
);
382 ptr
= start_of_text () + text_scnptr
;
383 end
= ptr
+ f_ohdr
.tsize
;
384 write_segment (new, ptr
, end
);
386 lseek (new, (long) data_scnptr
, SEEK_SET
);
387 ptr
= (char *) f_ohdr
.data_start
;
388 end
= ptr
+ f_ohdr
.dsize
;
389 write_segment (new, ptr
, end
);
394 #define UnexBlockSz (1<<12) /* read/write block size */
396 write_segment (int new, char *ptr
, char *end
)
400 char zeros
[UnexBlockSz
];
402 for (i
= 0; ptr
< end
;)
404 /* distance to next block. */
405 nwrite
= (((int) ptr
+ UnexBlockSz
) & -UnexBlockSz
) - (int) ptr
;
406 /* But not beyond specified end. */
407 if (nwrite
> end
- ptr
) nwrite
= end
- ptr
;
408 ret
= write (new, ptr
, nwrite
);
409 /* If write gets a page fault, it means we reached
410 a gap between the old text segment and the old data segment.
411 This gap has probably been remapped into part of the text segment.
412 So write zeros for it. */
413 if (ret
== -1 && errno
== EFAULT
)
415 memset (zeros
, 0, nwrite
);
416 write (new, zeros
, nwrite
);
418 else if (nwrite
!= ret
)
421 "unexec write failure: addr 0x%lx, fileno %d, size 0x%x, wrote 0x%x, errno %d",
422 (unsigned long)ptr
, new, nwrite
, ret
, errno
);
430 /* ****************************************************************
433 * Copy the relocation information and symbol table from the a.out to the new
436 copy_sym (int new, int a_out
, const char *a_name
, const char *new_name
)
438 char page
[UnexBlockSz
];
444 if (orig_load_scnptr
== 0L)
447 if (lnnoptr
&& lnnoptr
< orig_load_scnptr
) /* if there is line number info */
448 lseek (a_out
, lnnoptr
, SEEK_SET
); /* start copying from there */
450 lseek (a_out
, orig_load_scnptr
, SEEK_SET
); /* Position a.out to symtab. */
452 while ((n
= read (a_out
, page
, sizeof page
)) > 0)
454 if (write (new, page
, n
) != n
)
466 /* ****************************************************************
469 * After successfully building the new a.out, mark it executable
472 mark_x (const char *name
)
476 int new = 0; /* for PERROR */
480 if (stat (name
, &sbuf
) == -1)
484 sbuf
.st_mode
|= 0111 & ~um
;
485 if (chmod (name
, sbuf
.st_mode
) == -1)
490 adjust_lnnoptrs (int writedesc
, int readdesc
, const char *new_name
)
495 struct syment symentry
;
496 union auxent auxentry
;
498 if (!lnnoptr
|| !f_hdr
.f_symptr
)
501 if ((new = open (new_name
, O_RDWR
)) < 0)
507 lseek (new, f_hdr
.f_symptr
, SEEK_SET
);
508 for (nsyms
= 0; nsyms
< f_hdr
.f_nsyms
; nsyms
++)
510 read (new, &symentry
, SYMESZ
);
511 if (symentry
.n_sclass
== C_BINCL
|| symentry
.n_sclass
== C_EINCL
)
513 symentry
.n_value
+= bias
;
514 lseek (new, -SYMESZ
, SEEK_CUR
);
515 write (new, &symentry
, SYMESZ
);
518 for (naux
= symentry
.n_numaux
; naux
-- != 0; )
520 read (new, &auxentry
, AUXESZ
);
522 if (naux
!= 0 /* skip csect auxentry (last entry) */
523 && (symentry
.n_sclass
== C_EXT
|| symentry
.n_sclass
== C_HIDEXT
))
525 auxentry
.x_sym
.x_fcnary
.x_fcn
.x_lnnoptr
+= bias
;
526 lseek (new, -AUXESZ
, SEEK_CUR
);
527 write (new, &auxentry
, AUXESZ
);
537 unrelocate_symbols (int new, int a_out
,
538 const char *a_name
, const char *new_name
)
543 ulong t_reloc
= (ulong
) &_text
- f_ohdr
.text_start
;
544 #ifndef ALIGN_DATA_RELOC
545 ulong d_reloc
= (ulong
) &_data
- f_ohdr
.data_start
;
547 /* This worked (and was needed) before AIX 4.2.
548 I have no idea why. -- Mike */
549 ulong d_reloc
= (ulong
) &_data
- ALIGN (f_ohdr
.data_start
, 2);
553 if (load_scnptr
== 0)
556 lseek (a_out
, orig_load_scnptr
, SEEK_SET
);
557 if (read (a_out
, &ldhdr
, sizeof (ldhdr
)) != sizeof (ldhdr
))
562 #define SYMNDX_TEXT 0
563 #define SYMNDX_DATA 1
566 for (i
= 0; i
< ldhdr
.l_nreloc
; i
++)
569 orig_load_scnptr
+ LDHDRSZ
+ LDSYMSZ
*ldhdr
.l_nsyms
+ LDRELSZ
*i
,
572 if (read (a_out
, &ldrel
, LDRELSZ
) != LDRELSZ
)
577 /* move the BSS loader symbols to the DATA segment */
578 if (ldrel
.l_symndx
== SYMNDX_BSS
)
580 ldrel
.l_symndx
= SYMNDX_DATA
;
583 load_scnptr
+ LDHDRSZ
+ LDSYMSZ
*ldhdr
.l_nsyms
+ LDRELSZ
*i
,
586 if (write (new, &ldrel
, LDRELSZ
) != LDRELSZ
)
592 if (ldrel
.l_rsecnm
== f_ohdr
.o_sndata
)
597 orig_data_scnptr
+ (ldrel
.l_vaddr
- f_ohdr
.data_start
),
600 if (read (a_out
, (void *) &orig_int
, sizeof (orig_int
))
601 != sizeof (orig_int
))
606 p
= (int *) (ldrel
.l_vaddr
+ d_reloc
);
608 switch (ldrel
.l_symndx
) {
610 orig_int
= * p
- t_reloc
;
615 orig_int
= * p
- d_reloc
;
622 data_scnptr
+ (ldrel
.l_vaddr
- f_ohdr
.data_start
),
624 if (write (new, (void *) &orig_int
, sizeof (orig_int
))
625 != sizeof (orig_int
))
636 * Return the address of the start of the text segment prior to
637 * doing an unexec. After unexec the return value is undefined.
638 * See crt0.c for further explanation and _start.
645 return ((char *) 0x10000000);