1 /* Copyright (C) 1985,86,87,88,92,93,94 Free Software Foundation, Inc.
3 This file is part of GNU Emacs.
5 GNU Emacs is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2, or (at your option)
10 GNU Emacs is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with GNU Emacs; see the file COPYING. If not, write to
17 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
21 * unexec.c - Convert a running program into an a.out file.
23 * Author: Spencer W. Thomas
24 * Computer Science Dept.
26 * Date: Tue Mar 2 1982
27 * Modified heavily since then.
30 * unexec (new_name, a_name, data_start, bss_start, entry_address)
31 * char *new_name, *a_name;
32 * unsigned data_start, bss_start, entry_address;
34 * Takes a snapshot of the program and makes an a.out format file in the
35 * file named by the string argument new_name.
36 * If a_name is non-NULL, the symbol table will be taken from the given file.
37 * On some machines, an existing a_name file is required.
39 * The boundaries within the a.out file may be adjusted with the data_start
40 * and bss_start arguments. Either or both may be given as 0 for defaults.
42 * Data_start gives the boundary between the text segment and the data
43 * segment of the program. The text segment can contain shared, read-only
44 * program code and literal data, while the data segment is always unshared
45 * and unprotected. Data_start gives the lowest unprotected address.
46 * The value you specify may be rounded down to a suitable boundary
47 * as required by the machine you are using.
49 * Specifying zero for data_start means the boundary between text and data
50 * should not be the same as when the program was loaded.
51 * If NO_REMAP is defined, the argument data_start is ignored and the
52 * segment boundaries are never changed.
54 * Bss_start indicates how much of the data segment is to be saved in the
55 * a.out file and restored when the program is executed. It gives the lowest
56 * unsaved address, and is rounded up to a page boundary. The default when 0
57 * is given assumes that the entire data segment is to be stored, including
58 * the previous data and bss as well as any additional storage allocated with
61 * The new file is set up to start at entry_address.
63 * If you make improvements I'd like to get them too.
64 * harpo!utah-cs!thomas, thomas@Utah-20
68 /* Modified to support SysVr3 shared libraries by James Van Artsdalen
69 * of Dell Computer Corporation. james@bigtex.cactus.org.
72 /* There are several compilation parameters affecting unexec:
76 Define this if your system uses COFF for executables.
80 Define this if you are using the GNU coff encapsulated a.out format.
81 This is closer to a.out than COFF. You should *not* define COFF if
82 you define COFF_ENCAPSULATE
84 Otherwise we assume you use Berkeley format.
88 Define this if you do not want to try to save Emacs's pure data areas
89 as part of the text segment.
91 Saving them as text is good because it allows users to share more.
93 However, on machines that locate the text area far from the data area,
94 the boundary cannot feasibly be moved. Such machines require
97 Also, remapping can cause trouble with the built-in startup routine
98 /lib/crt0.o, which defines `environ' as an initialized variable.
99 Dumping `environ' as pure does not work! So, to use remapping,
100 you must write a startup routine for your machine in Emacs's crt0.c.
101 If NO_REMAP is defined, Emacs uses the system's crt0.o.
105 Some machines that use COFF executables require that each section
106 start on a certain boundary *in the COFF file*. Such machines should
107 define SECTION_ALIGNMENT to a mask of the low-order bits that must be
108 zero on such a boundary. This mask is used to control padding between
109 segments in the COFF file.
111 If SECTION_ALIGNMENT is not defined, the segments are written
112 consecutively with no attempt at alignment. This is right for
117 Some machines require that the beginnings and ends of segments
118 *in core* be on certain boundaries. For most machines, a page
119 boundary is sufficient. That is the default. When a larger
120 boundary is needed, define SEGMENT_MASK to a mask of
121 the bits that must be zero on such a boundary.
125 Some machines count the a.out header as part of the size of the text
126 segment (a_text); they may actually load the header into core as the
127 first data in the text segment. Some have additional padding between
128 the header and the real text of the program that is counted in a_text.
130 For these machines, define A_TEXT_OFFSET(HDR) to examine the header
131 structure HDR and return the number of bytes to add to `a_text'
132 before writing it (above and beyond the number of bytes of actual
133 program text). HDR's standard fields are already correct, except that
134 this adjustment to the `a_text' field has not yet been made;
135 thus, the amount of offset can depend on the data in the file.
139 If defined, this macro specifies the number of bytes to seek into the
140 a.out file before starting to write the text segment.
144 For machines using COFF, this macro, if defined, is a value stored
145 into the magic number field of the output file.
149 This macro can be used to generate statements to adjust or
150 initialize nonstandard fields in the file header
154 Macro to correct an int which is the bit pattern of a pointer to a byte
155 into an int which is the number of a byte.
157 This macro has a default definition which is usually right.
158 This default definition is a no-op on most machines (where a
159 pointer looks like an int) but not on all machines.
164 #define PERROR(arg) perror (arg); return -1
168 #define PERROR(file) report_error (file, new)
171 #ifndef CANNOT_DUMP /* all rest of file! */
173 #ifndef CANNOT_UNEXEC /* most of rest of file */
175 #ifdef COFF_ENCAPSULATE
176 int need_coff_header
= 1;
177 #include <coff-encap/a.out.encap.h> /* The location might be a poor assumption */
181 #define filehdr external_filehdr
182 #define scnhdr external_scnhdr
183 #define syment external_syment
184 #define auxent external_auxent
185 #define n_numaux e_numaux
186 #define n_type e_type
189 unsigned short magic
; /* type of file */
190 unsigned short vstamp
; /* version stamp */
191 unsigned long tsize
; /* text size in bytes, padded to FW bdry*/
192 unsigned long dsize
; /* initialized data " " */
193 unsigned long bsize
; /* uninitialized data " " */
194 unsigned long entry
; /* entry pt. */
195 unsigned long text_start
;/* base of text used for this file */
196 unsigned long data_start
;/* base of data used for this file */
200 #else /* not MSDOS */
202 #endif /* not MSDOS */
205 /* Define getpagesize () if the system does not.
206 Note that this may depend on symbols defined in a.out.h
208 #include "getpagesize.h"
210 #ifndef makedev /* Try to detect types.h already loaded */
211 #include <sys/types.h>
214 #include <sys/stat.h>
217 #include <sys/file.h> /* Must be after sys/types.h for USG and BSD4_1*/
231 extern char *start_of_text (); /* Start of text */
232 extern char *start_of_data (); /* Start of initialized data */
235 static long block_copy_start
; /* Old executable start point */
236 static struct filehdr f_hdr
; /* File header */
237 static struct aouthdr f_ohdr
; /* Optional file header (a.out) */
238 long bias
; /* Bias to add for growth */
239 long lnnoptr
; /* Pointer to line-number info within file */
240 #define SYMS_START block_copy_start
242 static long text_scnptr
;
243 static long data_scnptr
;
248 extern void *sbrk ();
251 /* Some systems with __STDC__ compilers still declare this `char *' in some
252 header file, and our declaration conflicts. The return value is always
253 cast, so it should be harmless to leave it undefined. Hopefully
254 machines with different size pointers and ints declare sbrk in a header
257 extern void *sbrk ();
259 extern char *sbrk ();
260 #endif /* __STDC__ */
264 #define SYMS_START ((long) N_SYMOFF (ohdr))
266 /* Some machines override the structure name for an a.out header. */
267 #ifndef EXEC_HDR_TYPE
268 #define EXEC_HDR_TYPE struct exec
273 #define MY_ID HP9000S200_ID
277 #endif /* no HP9000S200_ID */
278 static MAGIC OLDMAGIC
= {MY_ID
, SHARE_MAGIC
};
279 static MAGIC NEWMAGIC
= {MY_ID
, DEMAND_MAGIC
};
280 #define N_TXTOFF(x) TEXT_OFFSET(x)
281 #define N_SYMOFF(x) LESYM_OFFSET(x)
282 static EXEC_HDR_TYPE hdr
, ohdr
;
286 #if defined (USG) && !defined (IBMAIX) && !defined (IRIS) && !defined (COFF_ENCAPSULATE) && !defined (LINUX)
287 static struct bhdr hdr
, ohdr
;
288 #define a_magic fmagic
293 #define a_trsize rtsize
294 #define a_drsize rdsize
295 #define a_entry entry
296 #define N_BADMAG(x) \
297 (((x).fmagic)!=OMAGIC && ((x).fmagic)!=NMAGIC &&\
298 ((x).fmagic)!=FMAGIC && ((x).fmagic)!=IMAGIC)
299 #define NEWMAGIC FMAGIC
300 #else /* IRIS or IBMAIX or not USG */
301 static EXEC_HDR_TYPE hdr
, ohdr
;
302 #define NEWMAGIC ZMAGIC
303 #endif /* IRIS or IBMAIX not USG */
304 #endif /* not HPUX */
306 static int unexec_text_start
;
307 static int unexec_data_start
;
309 #ifdef COFF_ENCAPSULATE
310 /* coffheader is defined in the GNU a.out.encap.h file. */
311 struct coffheader coffheader
;
314 #endif /* not COFF */
318 /* Correct an int which is the bit pattern of a pointer to a byte
319 into an int which is the number of a byte.
320 This is a no-op on ordinary machines, but not on all. */
322 #ifndef ADDR_CORRECT /* Let m-*.h files override this definition */
323 #define ADDR_CORRECT(x) ((char *)(x) - (char*)0)
331 report_error (file
, fd
)
337 report_file_error ("Cannot unexec", Fcons (build_string (file
), Qnil
));
341 #define ERROR0(msg) report_error_1 (new, msg, 0, 0); return -1
342 #define ERROR1(msg,x) report_error_1 (new, msg, x, 0); return -1
343 #define ERROR2(msg,x,y) report_error_1 (new, msg, x, y); return -1
346 report_error_1 (fd
, msg
, a1
, a2
)
355 fprintf (stderr
, msg
, a1
, a2
);
356 fprintf (stderr
, "\n");
360 static int make_hdr ();
361 static int copy_text_and_data ();
362 static int copy_sym ();
363 static void mark_x ();
365 /* ****************************************************************
370 unexec (new_name
, a_name
, data_start
, bss_start
, entry_address
)
371 char *new_name
, *a_name
;
372 unsigned data_start
, bss_start
, entry_address
;
376 if (a_name
&& (a_out
= open (a_name
, O_RDONLY
)) < 0)
380 if ((new = creat (new_name
, 0666)) < 0)
385 if (make_hdr (new, a_out
, data_start
, bss_start
, entry_address
, a_name
, new_name
) < 0
386 || copy_text_and_data (new, a_out
) < 0
387 || copy_sym (new, a_out
, a_name
, new_name
) < 0
389 #ifndef COFF_BSD_SYMBOLS
390 || adjust_lnnoptrs (new, a_out
, new_name
) < 0
396 /* unlink (new_name); /* Failed, unlink new a.out */
407 /* ****************************************************************
410 * Make the header in the new a.out from the header in core.
411 * Modify the text and data sizes.
414 make_hdr (new, a_out
, data_start
, bss_start
, entry_address
, a_name
, new_name
)
416 unsigned data_start
, bss_start
, entry_address
;
422 auto struct scnhdr f_thdr
; /* Text section header */
423 auto struct scnhdr f_dhdr
; /* Data section header */
424 auto struct scnhdr f_bhdr
; /* Bss section header */
425 auto struct scnhdr scntemp
; /* Temporary section header */
428 #ifdef USG_SHARED_LIBRARIES
429 extern unsigned int bss_end
;
431 unsigned int bss_end
;
434 pagemask
= getpagesize () - 1;
436 /* Adjust text/data boundary. */
438 data_start
= (int) start_of_data ();
439 #else /* not NO_REMAP */
441 data_start
= (int) start_of_data ();
442 #endif /* not NO_REMAP */
443 data_start
= ADDR_CORRECT (data_start
);
446 data_start
= data_start
& ~SEGMENT_MASK
; /* (Down) to segment boundary. */
448 data_start
= data_start
& ~pagemask
; /* (Down) to page boundary. */
451 bss_end
= ADDR_CORRECT (sbrk (0)) + pagemask
;
452 bss_end
&= ~ pagemask
;
454 /* Adjust data/bss boundary. */
457 bss_start
= (ADDR_CORRECT (bss_start
) + pagemask
);
458 /* (Up) to page bdry. */
459 bss_start
&= ~ pagemask
;
460 if (bss_start
> bss_end
)
462 ERROR1 ("unexec: Specified bss_start (%u) is past end of program",
469 if (data_start
> bss_start
) /* Can't have negative data size. */
471 ERROR2 ("unexec: data_start (%u) can't be greater than bss_start (%u)",
472 data_start
, bss_start
);
476 /* Salvage as much info from the existing file as possible */
479 if (read (a_out
, &f_hdr
, sizeof (f_hdr
)) != sizeof (f_hdr
))
483 block_copy_start
+= sizeof (f_hdr
);
484 if (f_hdr
.f_opthdr
> 0)
486 if (read (a_out
, &f_ohdr
, sizeof (f_ohdr
)) != sizeof (f_ohdr
))
490 block_copy_start
+= sizeof (f_ohdr
);
492 /* Loop through section headers, copying them in */
493 lseek (a_out
, sizeof (f_hdr
) + f_hdr
.f_opthdr
, 0);
494 for (scns
= f_hdr
.f_nscns
; scns
> 0; scns
--) {
495 if (read (a_out
, &scntemp
, sizeof (scntemp
)) != sizeof (scntemp
))
499 if (scntemp
.s_scnptr
> 0L)
501 if (block_copy_start
< scntemp
.s_scnptr
+ scntemp
.s_size
)
502 block_copy_start
= scntemp
.s_scnptr
+ scntemp
.s_size
;
504 if (strcmp (scntemp
.s_name
, ".text") == 0)
508 else if (strcmp (scntemp
.s_name
, ".data") == 0)
512 else if (strcmp (scntemp
.s_name
, ".bss") == 0)
520 ERROR0 ("can't build a COFF file from scratch yet");
523 /* Now we alter the contents of all the f_*hdr variables
524 to correspond to what we want to dump. */
526 #ifdef USG_SHARED_LIBRARIES
528 /* The amount of data we're adding to the file is distance from the
529 * end of the original .data space to the current end of the .data
533 bias
= bss_start
- (f_ohdr
.data_start
+ f_dhdr
.s_size
);
537 f_hdr
.f_flags
|= (F_RELFLG
| F_EXEC
);
542 f_ohdr
.magic
= EXEC_MAGIC
;
545 f_ohdr
.text_start
= (long) start_of_text ();
546 f_ohdr
.tsize
= data_start
- f_ohdr
.text_start
;
547 f_ohdr
.data_start
= data_start
;
548 #endif /* NO_REMAP */
549 f_ohdr
.dsize
= bss_start
- f_ohdr
.data_start
;
550 f_ohdr
.bsize
= bss_end
- bss_start
;
551 #ifndef KEEP_OLD_TEXT_SCNPTR
552 /* On some machines, the old values are right.
553 ??? Maybe on all machines with NO_REMAP. */
554 f_thdr
.s_size
= f_ohdr
.tsize
;
555 f_thdr
.s_scnptr
= sizeof (f_hdr
) + sizeof (f_ohdr
);
556 f_thdr
.s_scnptr
+= (f_hdr
.f_nscns
) * (sizeof (f_thdr
));
557 #endif /* KEEP_OLD_TEXT_SCNPTR */
558 #ifdef ADJUST_TEXT_SCNHDR_SIZE
559 /* On some machines, `text size' includes all headers. */
560 f_thdr
.s_size
-= f_thdr
.s_scnptr
;
561 #endif /* ADJUST_TEST_SCNHDR_SIZE */
562 lnnoptr
= f_thdr
.s_lnnoptr
;
563 #ifdef SECTION_ALIGNMENT
564 /* Some systems require special alignment
565 of the sections in the file itself. */
567 = (f_thdr
.s_scnptr
+ SECTION_ALIGNMENT
) & ~SECTION_ALIGNMENT
;
568 #endif /* SECTION_ALIGNMENT */
570 f_thdr
.s_scnptr
= 0xd0;
572 text_scnptr
= f_thdr
.s_scnptr
;
573 #ifdef ADJUST_TEXTBASE
574 text_scnptr
= sizeof (f_hdr
) + sizeof (f_ohdr
) + (f_hdr
.f_nscns
) * (sizeof (f_thdr
));
576 #ifndef KEEP_OLD_PADDR
577 f_dhdr
.s_paddr
= f_ohdr
.data_start
;
578 #endif /* KEEP_OLD_PADDR */
579 f_dhdr
.s_vaddr
= f_ohdr
.data_start
;
580 f_dhdr
.s_size
= f_ohdr
.dsize
;
581 f_dhdr
.s_scnptr
= f_thdr
.s_scnptr
+ f_thdr
.s_size
;
582 #ifdef SECTION_ALIGNMENT
583 /* Some systems require special alignment
584 of the sections in the file itself. */
586 = (f_dhdr
.s_scnptr
+ SECTION_ALIGNMENT
) & ~SECTION_ALIGNMENT
;
587 #endif /* SECTION_ALIGNMENT */
588 #ifdef DATA_SECTION_ALIGNMENT
589 /* Some systems require special alignment
590 of the data section only. */
592 = (f_dhdr
.s_scnptr
+ DATA_SECTION_ALIGNMENT
) & ~DATA_SECTION_ALIGNMENT
;
593 #endif /* DATA_SECTION_ALIGNMENT */
594 data_scnptr
= f_dhdr
.s_scnptr
;
595 #ifndef KEEP_OLD_PADDR
596 f_bhdr
.s_paddr
= f_ohdr
.data_start
+ f_ohdr
.dsize
;
597 #endif /* KEEP_OLD_PADDR */
598 f_bhdr
.s_vaddr
= f_ohdr
.data_start
+ f_ohdr
.dsize
;
599 f_bhdr
.s_size
= f_ohdr
.bsize
;
600 f_bhdr
.s_scnptr
= 0L;
601 #ifndef USG_SHARED_LIBRARIES
602 bias
= f_dhdr
.s_scnptr
+ f_dhdr
.s_size
- block_copy_start
;
605 if (f_hdr
.f_symptr
> 0L)
607 f_hdr
.f_symptr
+= bias
;
610 if (f_thdr
.s_lnnoptr
> 0L)
612 f_thdr
.s_lnnoptr
+= bias
;
615 #ifdef ADJUST_EXEC_HEADER
617 #endif /* ADJUST_EXEC_HEADER */
619 if (write (new, &f_hdr
, sizeof (f_hdr
)) != sizeof (f_hdr
))
624 if (write (new, &f_ohdr
, sizeof (f_ohdr
)) != sizeof (f_ohdr
))
629 #ifndef USG_SHARED_LIBRARIES
631 if (write (new, &f_thdr
, sizeof (f_thdr
)) != sizeof (f_thdr
))
636 if (write (new, &f_dhdr
, sizeof (f_dhdr
)) != sizeof (f_dhdr
))
641 if (write (new, &f_bhdr
, sizeof (f_bhdr
)) != sizeof (f_bhdr
))
646 #else /* USG_SHARED_LIBRARIES */
648 /* The purpose of this code is to write out the new file's section
651 * Scan through the original file's sections. If the encountered
652 * section is one we know (.text, .data or .bss), write out the
653 * correct header. If it is a section we do not know (such as
654 * .lib), adjust the address of where the section data is in the
655 * file, and write out the header.
657 * If any section precedes .text or .data in the file, this code
658 * will not adjust the file pointer for that section correctly.
661 /* This used to use sizeof (f_ohdr) instead of .f_opthdr.
662 .f_opthdr is said to be right when there is no optional header. */
663 lseek (a_out
, sizeof (f_hdr
) + f_hdr
.f_opthdr
, 0);
665 for (scns
= f_hdr
.f_nscns
; scns
> 0; scns
--)
667 if (read (a_out
, &scntemp
, sizeof (scntemp
)) != sizeof (scntemp
))
670 if (!strcmp (scntemp
.s_name
, f_thdr
.s_name
)) /* .text */
672 if (write (new, &f_thdr
, sizeof (f_thdr
)) != sizeof (f_thdr
))
675 else if (!strcmp (scntemp
.s_name
, f_dhdr
.s_name
)) /* .data */
677 if (write (new, &f_dhdr
, sizeof (f_dhdr
)) != sizeof (f_dhdr
))
680 else if (!strcmp (scntemp
.s_name
, f_bhdr
.s_name
)) /* .bss */
682 if (write (new, &f_bhdr
, sizeof (f_bhdr
)) != sizeof (f_bhdr
))
687 if (scntemp
.s_scnptr
)
688 scntemp
.s_scnptr
+= bias
;
689 if (write (new, &scntemp
, sizeof (scntemp
)) != sizeof (scntemp
))
693 #endif /* USG_SHARED_LIBRARIES */
697 #else /* if not COFF */
699 /* Get symbol table info from header of a.out file if given one. */
702 #ifdef COFF_ENCAPSULATE
703 if (read (a_out
, &coffheader
, sizeof coffheader
) != sizeof coffheader
)
707 if (coffheader
.f_magic
!= COFF_MAGIC
)
709 ERROR1("%s doesn't have legal coff magic number\n", a_name
);
712 if (read (a_out
, &ohdr
, sizeof hdr
) != sizeof hdr
)
719 ERROR1 ("invalid magic number in %s", a_name
);
725 #ifdef COFF_ENCAPSULATE
726 /* We probably could without too much trouble. The code is in gld
727 * but I don't have that much time or incentive.
729 ERROR0 ("can't build a COFF file from scratch yet");
731 #ifdef MSDOS /* Demacs 1.1.1 91/10/16 HIRANO Satoshi */
732 bzero ((void *)&hdr
, sizeof hdr
);
734 bzero (&hdr
, sizeof hdr
);
739 unexec_text_start
= (long) start_of_text ();
740 unexec_data_start
= data_start
;
742 /* Machine-dependent fixup for header, or maybe for unexec_text_start */
743 #ifdef ADJUST_EXEC_HEADER
745 #endif /* ADJUST_EXEC_HEADER */
749 if (entry_address
!= 0)
750 hdr
.a_entry
= entry_address
;
752 hdr
.a_bss
= bss_end
- bss_start
;
753 hdr
.a_data
= bss_start
- data_start
;
755 hdr
.a_text
= ohdr
.a_text
;
756 #else /* not NO_REMAP */
757 hdr
.a_text
= data_start
- unexec_text_start
;
760 hdr
.a_text
+= A_TEXT_OFFSET (ohdr
);
763 #endif /* not NO_REMAP */
765 #ifdef COFF_ENCAPSULATE
766 /* We are encapsulating BSD format within COFF format. */
768 struct coffscn
*tp
, *dp
, *bp
;
769 tp
= &coffheader
.scns
[0];
770 dp
= &coffheader
.scns
[1];
771 bp
= &coffheader
.scns
[2];
772 tp
->s_size
= hdr
.a_text
+ sizeof(struct exec
);
773 dp
->s_paddr
= data_start
;
774 dp
->s_vaddr
= data_start
;
775 dp
->s_size
= hdr
.a_data
;
776 bp
->s_paddr
= dp
->s_vaddr
+ dp
->s_size
;
777 bp
->s_vaddr
= bp
->s_paddr
;
778 bp
->s_size
= hdr
.a_bss
;
779 coffheader
.tsize
= tp
->s_size
;
780 coffheader
.dsize
= dp
->s_size
;
781 coffheader
.bsize
= bp
->s_size
;
782 coffheader
.text_start
= tp
->s_vaddr
;
783 coffheader
.data_start
= dp
->s_vaddr
;
785 if (write (new, &coffheader
, sizeof coffheader
) != sizeof coffheader
)
789 #endif /* COFF_ENCAPSULATE */
791 if (write (new, &hdr
, sizeof hdr
) != sizeof hdr
)
796 /* This adjustment was done above only #ifndef NO_REMAP,
797 so only undo it now #ifndef NO_REMAP. */
800 hdr
.a_text
-= A_TEXT_OFFSET (ohdr
);
806 #endif /* not COFF */
809 /* ****************************************************************
812 * Copy the text and data segments from memory to the new a.out
815 copy_text_and_data (new, a_out
)
823 #ifdef USG_SHARED_LIBRARIES
826 struct scnhdr scntemp
; /* Temporary section header */
828 /* The purpose of this code is to write out the new file's section
831 * Step through the section table. If we know the section (.text,
832 * .data) do the appropriate thing. Otherwise, if the section has
833 * no allocated space in the file (.bss), do nothing. Otherwise,
834 * the section has space allocated in the file, and is not a section
835 * we know. So just copy it.
838 lseek (a_out
, sizeof (struct filehdr
) + sizeof (struct aouthdr
), 0);
840 for (scns
= f_hdr
.f_nscns
; scns
> 0; scns
--)
842 if (read (a_out
, &scntemp
, sizeof (scntemp
)) != sizeof (scntemp
))
845 if (!strcmp (scntemp
.s_name
, ".text"))
847 lseek (new, (long) text_scnptr
, 0);
848 ptr
= (char *) f_ohdr
.text_start
;
849 end
= ptr
+ f_ohdr
.tsize
;
850 write_segment (new, ptr
, end
);
852 else if (!strcmp (scntemp
.s_name
, ".data"))
854 lseek (new, (long) data_scnptr
, 0);
855 ptr
= (char *) f_ohdr
.data_start
;
856 end
= ptr
+ f_ohdr
.dsize
;
857 write_segment (new, ptr
, end
);
859 else if (!scntemp
.s_scnptr
)
860 ; /* do nothing - no data for this section */
865 long old_a_out_ptr
= lseek (a_out
, 0, 1);
867 lseek (a_out
, scntemp
.s_scnptr
, 0);
868 for (size
= scntemp
.s_size
; size
> 0; size
-= sizeof (page
))
870 n
= size
> sizeof (page
) ? sizeof (page
) : size
;
871 if (read (a_out
, page
, n
) != n
|| write (new, page
, n
) != n
)
874 lseek (a_out
, old_a_out_ptr
, 0);
878 #else /* COFF, but not USG_SHARED_LIBRARIES */
880 lseek (new, (long) text_scnptr
, 0);
881 ptr
= (char *) f_ohdr
.text_start
;
882 #ifdef HEADER_INCL_IN_TEXT
883 /* For Gould UTX/32, text starts after headers */
884 ptr
= (char *) (ptr
+ text_scnptr
);
885 #endif /* HEADER_INCL_IN_TEXT */
886 end
= ptr
+ f_ohdr
.tsize
;
887 write_segment (new, ptr
, end
);
889 lseek (new, (long) data_scnptr
, 0);
890 ptr
= (char *) f_ohdr
.data_start
;
891 end
= ptr
+ f_ohdr
.dsize
;
892 write_segment (new, ptr
, end
);
894 #endif /* USG_SHARED_LIBRARIES */
896 #else /* if not COFF */
898 /* Some machines count the header as part of the text segment.
899 That is to say, the header appears in core
900 just before the address that start_of_text () returns.
901 For them, N_TXTOFF is the place where the header goes.
902 We must adjust the seek to the place after the header.
903 Note that at this point hdr.a_text does *not* count
904 the extra A_TEXT_OFFSET bytes, only the actual bytes of code. */
907 lseek (new, (long) A_TEXT_SEEK (hdr
), 0);
909 lseek (new, (long) N_TXTOFF (hdr
), 0);
910 #endif /* no A_TEXT_SEEK */
914 /* Acorn's RISC-iX has a wacky way of initialising the position of the heap.
915 * There is a little table in crt0.o that is filled at link time with
916 * the min and current brk positions, among other things. When start()
917 * runs, it copies the table to where these parameters live during
918 * execution. This data is in text space, so it cannot be modified here
919 * before saving the executable, so the data is written manually. In
920 * addition, the table does not have a label, and the nearest accessable
921 * label (mcount) is not prefixed with a '_', thus making it inaccessable
922 * from within C programs. To overcome this, emacs's executable is passed
923 * through the command 'nm %s | fgrep mcount' into a pipe, and the
924 * resultant output is then used to find the address of 'mcount'. As far as
925 * is possible to determine, in RISC-iX releases prior to 1.2, the negative
926 * offset of the table from mcount is 0x2c, whereas from 1.2 onwards it is
927 * 0x30. bss_end has been rounded up to page boundary. This solution is
928 * based on suggestions made by Kevin Welton and Steve Hunt of Acorn, and
929 * avoids the need for a custom version of crt0.o for emacs which has its
930 * table in data space.
936 char address_text
[32];
941 int mcount_address
, mcount_offset
, count
;
942 extern char *_execname
;
945 /* The use of _execname is incompatible with RISCiX 1.1 */
946 sprintf (command
, "nm %s | fgrep mcount", _execname
);
948 if ( (pfile
= popen(command
, "r")) == NULL
)
950 sprintf (errbuf
, "Could not open pipe");
955 while ( ((c
=getc(pfile
)) != EOF
) && (c
!= ' ') && (count
< 31))
956 address_text
[count
++]=c
;
957 address_text
[count
]=0;
959 if ((count
== 0) || pclose(pfile
) != NULL
)
961 sprintf (errbuf
, "Failed to execute the command '%s'\n", command
);
965 sscanf(address_text
, "%x", &mcount_address
);
966 ptr
= (char *) unexec_text_start
;
967 mcount_offset
= (char *)mcount_address
- ptr
;
970 #define EDATA_OFFSET 0x2c
972 #define EDATA_OFFSET 0x30
975 end
= ptr
+ mcount_offset
- EDATA_OFFSET
;
976 printf ("Writing from %08x to %08x\n", ptr
, end
);
978 write_segment (new, ptr
, end
);
980 proforma
[0] = bss_end
; /* becomes _edata */
981 proforma
[1] = bss_end
; /* becomes _end */
982 proforma
[2] = bss_end
; /* becomes _minbrk */
983 proforma
[3] = bss_end
; /* becomes _curbrk */
985 puts ("Writing 'args_proforma' (16 bytes)");
986 write (new, proforma
, 16);
990 end
= temp_ptr
+ hdr
.a_text
;
992 printf ("Writing from %08x to %08x\n", ptr
, end
);
993 write_segment (new, ptr
, end
);
997 ptr
= (char *) unexec_text_start
;
998 end
= ptr
+ hdr
.a_text
;
999 write_segment (new, ptr
, end
);
1002 ptr
= (char *) unexec_data_start
;
1003 end
= ptr
+ hdr
.a_data
;
1004 /* This lseek is certainly incorrect when A_TEXT_OFFSET
1005 and I believe it is a no-op otherwise.
1006 Let's see if its absence ever fails. */
1007 /* lseek (new, (long) N_TXTOFF (hdr) + hdr.a_text, 0); */
1008 write_segment (new, ptr
, end
);
1010 #endif /* not COFF */
1015 write_segment (new, ptr
, end
)
1017 register char *ptr
, *end
;
1019 register int i
, nwrite
, ret
;
1024 bzero (zeros
, sizeof zeros
);
1026 for (i
= 0; ptr
< end
;)
1028 /* distance to next multiple of 128. */
1029 nwrite
= (((int) ptr
+ 128) & -128) - (int) ptr
;
1030 /* But not beyond specified end. */
1031 if (nwrite
> end
- ptr
) nwrite
= end
- ptr
;
1032 ret
= write (new, ptr
, nwrite
);
1033 /* If write gets a page fault, it means we reached
1034 a gap between the old text segment and the old data segment.
1035 This gap has probably been remapped into part of the text segment.
1036 So write zeros for it. */
1042 write (new, zeros
, nwrite
);
1043 else if (nwrite
!= ret
)
1046 "unexec write failure: addr 0x%x, fileno %d, size 0x%x, wrote 0x%x, errno %d",
1047 ptr
, new, nwrite
, ret
, errno
);
1055 /* ****************************************************************
1058 * Copy the relocation information and symbol table from the a.out to the new
1061 copy_sym (new, a_out
, a_name
, new_name
)
1063 char *a_name
, *new_name
;
1072 if (SYMS_START
== 0L)
1077 if (lnnoptr
) /* if there is line number info */
1078 lseek (a_out
, lnnoptr
, 0); /* start copying from there */
1081 lseek (a_out
, SYMS_START
, 0); /* Position a.out to symtab. */
1083 while ((n
= read (a_out
, page
, sizeof page
)) > 0)
1085 if (write (new, page
, n
) != n
)
1097 /* ****************************************************************
1100 * After successfully building the new a.out, mark it executable
1108 int new = 0; /* for PERROR */
1112 if (stat (name
, &sbuf
) == -1)
1116 sbuf
.st_mode
|= 0111 & ~um
;
1117 if (chmod (name
, sbuf
.st_mode
) == -1)
1122 #ifndef COFF_BSD_SYMBOLS
1125 * If the COFF file contains a symbol table and a line number section,
1126 * then any auxiliary entries that have values for x_lnnoptr must
1127 * be adjusted by the amount that the line number section has moved
1128 * in the file (bias computed in make_hdr). The #@$%&* designers of
1129 * the auxiliary entry structures used the absolute file offsets for
1130 * the line number entry rather than an offset from the start of the
1131 * line number section!
1133 * When I figure out how to scan through the symbol table and pick out
1134 * the auxiliary entries that need adjustment, this routine will
1135 * be fixed. As it is now, all such entries are wrong and sdb
1136 * will complain. Fred Fish, UniSoft Systems Inc.
1139 /* This function is probably very slow. Instead of reopening the new
1140 file for input and output it should copy from the old to the new
1141 using the two descriptors already open (WRITEDESC and READDESC).
1142 Instead of reading one small structure at a time it should use
1143 a reasonable size buffer. But I don't have time to work on such
1144 things, so I am installing it as submitted to me. -- RMS. */
1146 adjust_lnnoptrs (writedesc
, readdesc
, new_name
)
1153 #if defined (amdahl_uts) || defined (pfa)
1157 struct syment symentry
;
1158 union auxent auxentry
;
1161 if (!lnnoptr
|| !f_hdr
.f_symptr
)
1165 if ((new = writedesc
) < 0)
1167 if ((new = open (new_name
, O_RDWR
)) < 0)
1174 lseek (new, f_hdr
.f_symptr
, 0);
1175 for (nsyms
= 0; nsyms
< f_hdr
.f_nsyms
; nsyms
++)
1177 read (new, &symentry
, SYMESZ
);
1178 if (symentry
.n_numaux
)
1180 read (new, &auxentry
, AUXESZ
);
1182 if (ISFCN (symentry
.n_type
) || symentry
.n_type
== 0x2400)
1184 auxentry
.x_sym
.x_fcnary
.x_fcn
.x_lnnoptr
+= bias
;
1185 lseek (new, -AUXESZ
, 1);
1186 write (new, &auxentry
, AUXESZ
);
1196 #endif /* COFF_BSD_SYMBOLS */
1200 #endif /* not CANNOT_UNEXEC */
1202 #endif /* not CANNOT_DUMP */