]>
code.delx.au - gnu-emacs/blob - src/unexec.c
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, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA. */
22 * unexec.c - Convert a running program into an a.out file.
24 * Author: Spencer W. Thomas
25 * Computer Science Dept.
27 * Date: Tue Mar 2 1982
28 * Modified heavily since then.
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 * The boundaries within the a.out file may be adjusted with the data_start
41 * and bss_start arguments. Either or both may be given as 0 for defaults.
43 * Data_start gives the boundary between the text segment and the data
44 * segment of the program. The text segment can contain shared, read-only
45 * program code and literal data, while the data segment is always unshared
46 * and unprotected. Data_start gives the lowest unprotected address.
47 * The value you specify may be rounded down to a suitable boundary
48 * as required by the machine you are using.
50 * Specifying zero for data_start means the boundary between text and data
51 * should not be the same as when the program was loaded.
52 * If NO_REMAP is defined, the argument data_start is ignored and the
53 * segment boundaries are never changed.
55 * Bss_start indicates how much of the data segment is to be saved in the
56 * a.out file and restored when the program is executed. It gives the lowest
57 * unsaved address, and is rounded up to a page boundary. The default when 0
58 * is given assumes that the entire data segment is to be stored, including
59 * the previous data and bss as well as any additional storage allocated with
62 * The new file is set up to start at entry_address.
64 * If you make improvements I'd like to get them too.
65 * harpo!utah-cs!thomas, thomas@Utah-20
69 /* Modified to support SysVr3 shared libraries by James Van Artsdalen
70 * of Dell Computer Corporation. james@bigtex.cactus.org.
73 /* There are several compilation parameters affecting unexec:
77 Define this if your system uses COFF for executables.
81 Define this if you are using the GNU coff encapsulated a.out format.
82 This is closer to a.out than COFF. You should *not* define COFF if
83 you define COFF_ENCAPSULATE
85 Otherwise we assume you use Berkeley format.
89 Define this if you do not want to try to save Emacs's pure data areas
90 as part of the text segment.
92 Saving them as text is good because it allows users to share more.
94 However, on machines that locate the text area far from the data area,
95 the boundary cannot feasibly be moved. Such machines require
98 Also, remapping can cause trouble with the built-in startup routine
99 /lib/crt0.o, which defines `environ' as an initialized variable.
100 Dumping `environ' as pure does not work! So, to use remapping,
101 you must write a startup routine for your machine in Emacs's crt0.c.
102 If NO_REMAP is defined, Emacs uses the system's crt0.o.
106 Some machines that use COFF executables require that each section
107 start on a certain boundary *in the COFF file*. Such machines should
108 define SECTION_ALIGNMENT to a mask of the low-order bits that must be
109 zero on such a boundary. This mask is used to control padding between
110 segments in the COFF file.
112 If SECTION_ALIGNMENT is not defined, the segments are written
113 consecutively with no attempt at alignment. This is right for
118 Some machines require that the beginnings and ends of segments
119 *in core* be on certain boundaries. For most machines, a page
120 boundary is sufficient. That is the default. When a larger
121 boundary is needed, define SEGMENT_MASK to a mask of
122 the bits that must be zero on such a boundary.
126 Some machines count the a.out header as part of the size of the text
127 segment (a_text); they may actually load the header into core as the
128 first data in the text segment. Some have additional padding between
129 the header and the real text of the program that is counted in a_text.
131 For these machines, define A_TEXT_OFFSET(HDR) to examine the header
132 structure HDR and return the number of bytes to add to `a_text'
133 before writing it (above and beyond the number of bytes of actual
134 program text). HDR's standard fields are already correct, except that
135 this adjustment to the `a_text' field has not yet been made;
136 thus, the amount of offset can depend on the data in the file.
140 If defined, this macro specifies the number of bytes to seek into the
141 a.out file before starting to write the text segment.
145 For machines using COFF, this macro, if defined, is a value stored
146 into the magic number field of the output file.
150 This macro can be used to generate statements to adjust or
151 initialize nonstandard fields in the file header
155 Macro to correct an int which is the bit pattern of a pointer to a byte
156 into an int which is the number of a byte.
158 This macro has a default definition which is usually right.
159 This default definition is a no-op on most machines (where a
160 pointer looks like an int) but not on all machines.
165 #define PERROR(arg) perror (arg); return -1
169 #define PERROR(file) report_error (file, new)
172 #ifndef CANNOT_DUMP /* all rest of file! */
174 #ifdef COFF_ENCAPSULATE
175 int need_coff_header
= 1;
176 #include <coff-encap/a.out.encap.h> /* The location might be a poor assumption */
180 #include <fcntl.h> /* for O_RDONLY, O_RDWR */
183 #define filehdr external_filehdr
184 #define scnhdr external_scnhdr
185 #define syment external_syment
186 #define auxent external_auxent
187 #define n_numaux e_numaux
188 #define n_type e_type
191 unsigned short magic
; /* type of file */
192 unsigned short vstamp
; /* version stamp */
193 unsigned long tsize
; /* text size in bytes, padded to FW bdry*/
194 unsigned long dsize
; /* initialized data " " */
195 unsigned long bsize
; /* uninitialized data " " */
196 unsigned long entry
; /* entry pt. */
197 unsigned long text_start
;/* base of text used for this file */
198 unsigned long data_start
;/* base of data used for this file */
202 #else /* not MSDOS */
204 #endif /* not MSDOS */
207 /* Define getpagesize if the system does not.
208 Note that this may depend on symbols defined in a.out.h. */
209 #include "getpagesize.h"
211 #ifndef makedev /* Try to detect types.h already loaded */
212 #include <sys/types.h>
215 #include <sys/stat.h>
218 #include <sys/file.h> /* Must be after sys/types.h for USG and BSD4_1*/
232 extern char *start_of_text (); /* Start of text */
233 extern char *start_of_data (); /* Start of initialized data */
236 static long block_copy_start
; /* Old executable start point */
237 static struct filehdr f_hdr
; /* File header */
238 static struct aouthdr f_ohdr
; /* Optional file header (a.out) */
239 long bias
; /* Bias to add for growth */
240 long lnnoptr
; /* Pointer to line-number info within file */
241 #define SYMS_START block_copy_start
243 static long text_scnptr
;
244 static long data_scnptr
;
249 extern void *sbrk ();
252 /* Some systems with __STDC__ compilers still declare this `char *' in some
253 header file, and our declaration conflicts. The return value is always
254 cast, so it should be harmless to leave it undefined. Hopefully
255 machines with different size pointers and ints declare sbrk in a header
258 extern void *sbrk ();
260 extern char *sbrk ();
261 #endif /* __STDC__ */
265 #define SYMS_START ((long) N_SYMOFF (ohdr))
267 /* Some machines override the structure name for an a.out header. */
268 #ifndef EXEC_HDR_TYPE
269 #define EXEC_HDR_TYPE struct exec
274 #define MY_ID HP9000S200_ID
278 #endif /* no HP9000S200_ID */
279 static MAGIC OLDMAGIC
= {MY_ID
, SHARE_MAGIC
};
280 static MAGIC NEWMAGIC
= {MY_ID
, DEMAND_MAGIC
};
281 #define N_TXTOFF(x) TEXT_OFFSET(x)
282 #define N_SYMOFF(x) LESYM_OFFSET(x)
283 static EXEC_HDR_TYPE hdr
, ohdr
;
287 #if defined (USG) && !defined (IBMAIX) && !defined (IRIS) && !defined (COFF_ENCAPSULATE) && !defined (LINUX)
288 static struct bhdr hdr
, ohdr
;
289 #define a_magic fmagic
294 #define a_trsize rtsize
295 #define a_drsize rdsize
296 #define a_entry entry
297 #define N_BADMAG(x) \
298 (((x).fmagic)!=OMAGIC && ((x).fmagic)!=NMAGIC &&\
299 ((x).fmagic)!=FMAGIC && ((x).fmagic)!=IMAGIC)
300 #define NEWMAGIC FMAGIC
301 #else /* IRIS or IBMAIX or not USG */
302 static EXEC_HDR_TYPE hdr
, ohdr
;
303 #define NEWMAGIC ZMAGIC
304 #endif /* IRIS or IBMAIX not USG */
305 #endif /* not HPUX */
307 static int unexec_text_start
;
308 static int unexec_data_start
;
310 #ifdef COFF_ENCAPSULATE
311 /* coffheader is defined in the GNU a.out.encap.h file. */
312 struct coffheader coffheader
;
315 #endif /* not COFF */
319 /* Correct an int which is the bit pattern of a pointer to a byte
320 into an int which is the number of a byte.
321 This is a no-op on ordinary machines, but not on all. */
323 #ifndef ADDR_CORRECT /* Let m-*.h files override this definition */
324 #define ADDR_CORRECT(x) ((char *)(x) - (char*)0)
332 report_error (file
, fd
)
338 report_file_error ("Cannot unexec", Fcons (build_string (file
), Qnil
));
342 #define ERROR0(msg) report_error_1 (new, msg, 0, 0); return -1
343 #define ERROR1(msg,x) report_error_1 (new, msg, x, 0); return -1
344 #define ERROR2(msg,x,y) report_error_1 (new, msg, x, y); return -1
347 report_error_1 (fd
, msg
, a1
, a2
)
356 fprintf (stderr
, msg
, a1
, a2
);
357 fprintf (stderr
, "\n");
361 static int make_hdr ();
362 static int copy_text_and_data ();
363 static int copy_sym ();
364 static void mark_x ();
366 /* ****************************************************************
371 unexec (new_name
, a_name
, data_start
, bss_start
, entry_address
)
372 char *new_name
, *a_name
;
373 unsigned data_start
, bss_start
, entry_address
;
377 if (a_name
&& (a_out
= open (a_name
, O_RDONLY
)) < 0)
381 if ((new = creat (new_name
, 0666)) < 0)
386 if (make_hdr (new, a_out
, data_start
, bss_start
, entry_address
, a_name
, new_name
) < 0
387 || copy_text_and_data (new, a_out
) < 0
388 || copy_sym (new, a_out
, a_name
, new_name
) < 0
390 #ifndef COFF_BSD_SYMBOLS
391 || adjust_lnnoptrs (new, a_out
, new_name
) < 0
397 /* unlink (new_name); /* Failed, unlink new a.out */
408 /* ****************************************************************
411 * Make the header in the new a.out from the header in core.
412 * Modify the text and data sizes.
415 make_hdr (new, a_out
, data_start
, bss_start
, entry_address
, a_name
, new_name
)
417 unsigned data_start
, bss_start
, entry_address
;
423 auto struct scnhdr f_thdr
; /* Text section header */
424 auto struct scnhdr f_dhdr
; /* Data section header */
425 auto struct scnhdr f_bhdr
; /* Bss section header */
426 auto struct scnhdr scntemp
; /* Temporary section header */
429 #ifdef USG_SHARED_LIBRARIES
430 extern unsigned int bss_end
;
432 unsigned int bss_end
;
435 pagemask
= getpagesize () - 1;
437 /* Adjust text/data boundary. */
439 data_start
= (int) start_of_data ();
440 #else /* not NO_REMAP */
442 data_start
= (int) start_of_data ();
443 #endif /* not NO_REMAP */
444 data_start
= ADDR_CORRECT (data_start
);
447 data_start
= data_start
& ~SEGMENT_MASK
; /* (Down) to segment boundary. */
449 data_start
= data_start
& ~pagemask
; /* (Down) to page boundary. */
452 bss_end
= ADDR_CORRECT (sbrk (0)) + pagemask
;
453 bss_end
&= ~ pagemask
;
455 /* Adjust data/bss boundary. */
458 bss_start
= (ADDR_CORRECT (bss_start
) + pagemask
);
459 /* (Up) to page bdry. */
460 bss_start
&= ~ pagemask
;
461 if (bss_start
> bss_end
)
463 ERROR1 ("unexec: Specified bss_start (%u) is past end of program",
470 if (data_start
> bss_start
) /* Can't have negative data size. */
472 ERROR2 ("unexec: data_start (%u) can't be greater than bss_start (%u)",
473 data_start
, bss_start
);
477 /* Salvage as much info from the existing file as possible */
480 if (read (a_out
, &f_hdr
, sizeof (f_hdr
)) != sizeof (f_hdr
))
484 block_copy_start
+= sizeof (f_hdr
);
485 if (f_hdr
.f_opthdr
> 0)
487 if (read (a_out
, &f_ohdr
, sizeof (f_ohdr
)) != sizeof (f_ohdr
))
491 block_copy_start
+= sizeof (f_ohdr
);
493 /* Loop through section headers, copying them in */
494 lseek (a_out
, sizeof (f_hdr
) + f_hdr
.f_opthdr
, 0);
495 for (scns
= f_hdr
.f_nscns
; scns
> 0; scns
--) {
496 if (read (a_out
, &scntemp
, sizeof (scntemp
)) != sizeof (scntemp
))
500 if (scntemp
.s_scnptr
> 0L)
502 if (block_copy_start
< scntemp
.s_scnptr
+ scntemp
.s_size
)
503 block_copy_start
= scntemp
.s_scnptr
+ scntemp
.s_size
;
505 if (strcmp (scntemp
.s_name
, ".text") == 0)
509 else if (strcmp (scntemp
.s_name
, ".data") == 0)
513 else if (strcmp (scntemp
.s_name
, ".bss") == 0)
521 ERROR0 ("can't build a COFF file from scratch yet");
524 /* Now we alter the contents of all the f_*hdr variables
525 to correspond to what we want to dump. */
527 #ifdef USG_SHARED_LIBRARIES
529 /* The amount of data we're adding to the file is distance from the
530 * end of the original .data space to the current end of the .data
534 bias
= bss_start
- (f_ohdr
.data_start
+ f_dhdr
.s_size
);
538 f_hdr
.f_flags
|= (F_RELFLG
| F_EXEC
);
543 f_ohdr
.magic
= EXEC_MAGIC
;
546 f_ohdr
.text_start
= (long) start_of_text ();
547 f_ohdr
.tsize
= data_start
- f_ohdr
.text_start
;
548 f_ohdr
.data_start
= data_start
;
549 #endif /* NO_REMAP */
550 f_ohdr
.dsize
= bss_start
- f_ohdr
.data_start
;
551 f_ohdr
.bsize
= bss_end
- bss_start
;
552 #ifndef KEEP_OLD_TEXT_SCNPTR
553 /* On some machines, the old values are right.
554 ??? Maybe on all machines with NO_REMAP. */
555 f_thdr
.s_size
= f_ohdr
.tsize
;
556 f_thdr
.s_scnptr
= sizeof (f_hdr
) + sizeof (f_ohdr
);
557 f_thdr
.s_scnptr
+= (f_hdr
.f_nscns
) * (sizeof (f_thdr
));
558 #endif /* KEEP_OLD_TEXT_SCNPTR */
559 #ifdef ADJUST_TEXT_SCNHDR_SIZE
560 /* On some machines, `text size' includes all headers. */
561 f_thdr
.s_size
-= f_thdr
.s_scnptr
;
562 #endif /* ADJUST_TEST_SCNHDR_SIZE */
563 lnnoptr
= f_thdr
.s_lnnoptr
;
564 #ifdef SECTION_ALIGNMENT
565 /* Some systems require special alignment
566 of the sections in the file itself. */
568 = (f_thdr
.s_scnptr
+ SECTION_ALIGNMENT
) & ~SECTION_ALIGNMENT
;
569 #endif /* SECTION_ALIGNMENT */
571 f_thdr
.s_scnptr
= 0xd0;
573 text_scnptr
= f_thdr
.s_scnptr
;
574 #ifdef ADJUST_TEXTBASE
575 text_scnptr
= sizeof (f_hdr
) + sizeof (f_ohdr
) + (f_hdr
.f_nscns
) * (sizeof (f_thdr
));
577 #ifndef KEEP_OLD_PADDR
578 f_dhdr
.s_paddr
= f_ohdr
.data_start
;
579 #endif /* KEEP_OLD_PADDR */
580 f_dhdr
.s_vaddr
= f_ohdr
.data_start
;
581 f_dhdr
.s_size
= f_ohdr
.dsize
;
582 f_dhdr
.s_scnptr
= f_thdr
.s_scnptr
+ f_thdr
.s_size
;
583 #ifdef SECTION_ALIGNMENT
584 /* Some systems require special alignment
585 of the sections in the file itself. */
587 = (f_dhdr
.s_scnptr
+ SECTION_ALIGNMENT
) & ~SECTION_ALIGNMENT
;
588 #endif /* SECTION_ALIGNMENT */
589 #ifdef DATA_SECTION_ALIGNMENT
590 /* Some systems require special alignment
591 of the data section only. */
593 = (f_dhdr
.s_scnptr
+ DATA_SECTION_ALIGNMENT
) & ~DATA_SECTION_ALIGNMENT
;
594 #endif /* DATA_SECTION_ALIGNMENT */
595 data_scnptr
= f_dhdr
.s_scnptr
;
596 #ifndef KEEP_OLD_PADDR
597 f_bhdr
.s_paddr
= f_ohdr
.data_start
+ f_ohdr
.dsize
;
598 #endif /* KEEP_OLD_PADDR */
599 f_bhdr
.s_vaddr
= f_ohdr
.data_start
+ f_ohdr
.dsize
;
600 f_bhdr
.s_size
= f_ohdr
.bsize
;
601 f_bhdr
.s_scnptr
= 0L;
602 #ifndef USG_SHARED_LIBRARIES
603 bias
= f_dhdr
.s_scnptr
+ f_dhdr
.s_size
- block_copy_start
;
606 if (f_hdr
.f_symptr
> 0L)
608 f_hdr
.f_symptr
+= bias
;
611 if (f_thdr
.s_lnnoptr
> 0L)
613 f_thdr
.s_lnnoptr
+= bias
;
616 #ifdef ADJUST_EXEC_HEADER
618 #endif /* ADJUST_EXEC_HEADER */
620 if (write (new, &f_hdr
, sizeof (f_hdr
)) != sizeof (f_hdr
))
625 if (write (new, &f_ohdr
, sizeof (f_ohdr
)) != sizeof (f_ohdr
))
630 #ifndef USG_SHARED_LIBRARIES
632 if (write (new, &f_thdr
, sizeof (f_thdr
)) != sizeof (f_thdr
))
637 if (write (new, &f_dhdr
, sizeof (f_dhdr
)) != sizeof (f_dhdr
))
642 if (write (new, &f_bhdr
, sizeof (f_bhdr
)) != sizeof (f_bhdr
))
647 #else /* USG_SHARED_LIBRARIES */
649 /* The purpose of this code is to write out the new file's section
652 * Scan through the original file's sections. If the encountered
653 * section is one we know (.text, .data or .bss), write out the
654 * correct header. If it is a section we do not know (such as
655 * .lib), adjust the address of where the section data is in the
656 * file, and write out the header.
658 * If any section precedes .text or .data in the file, this code
659 * will not adjust the file pointer for that section correctly.
662 /* This used to use sizeof (f_ohdr) instead of .f_opthdr.
663 .f_opthdr is said to be right when there is no optional header. */
664 lseek (a_out
, sizeof (f_hdr
) + f_hdr
.f_opthdr
, 0);
666 for (scns
= f_hdr
.f_nscns
; scns
> 0; scns
--)
668 if (read (a_out
, &scntemp
, sizeof (scntemp
)) != sizeof (scntemp
))
671 if (!strcmp (scntemp
.s_name
, f_thdr
.s_name
)) /* .text */
673 if (write (new, &f_thdr
, sizeof (f_thdr
)) != sizeof (f_thdr
))
676 else if (!strcmp (scntemp
.s_name
, f_dhdr
.s_name
)) /* .data */
678 if (write (new, &f_dhdr
, sizeof (f_dhdr
)) != sizeof (f_dhdr
))
681 else if (!strcmp (scntemp
.s_name
, f_bhdr
.s_name
)) /* .bss */
683 if (write (new, &f_bhdr
, sizeof (f_bhdr
)) != sizeof (f_bhdr
))
688 if (scntemp
.s_scnptr
)
689 scntemp
.s_scnptr
+= bias
;
690 if (write (new, &scntemp
, sizeof (scntemp
)) != sizeof (scntemp
))
694 #endif /* USG_SHARED_LIBRARIES */
698 #else /* if not COFF */
700 /* Get symbol table info from header of a.out file if given one. */
703 #ifdef COFF_ENCAPSULATE
704 if (read (a_out
, &coffheader
, sizeof coffheader
) != sizeof coffheader
)
708 if (coffheader
.f_magic
!= COFF_MAGIC
)
710 ERROR1("%s doesn't have legal coff magic number\n", a_name
);
713 if (read (a_out
, &ohdr
, sizeof hdr
) != sizeof hdr
)
720 ERROR1 ("invalid magic number in %s", a_name
);
726 #ifdef COFF_ENCAPSULATE
727 /* We probably could without too much trouble. The code is in gld
728 * but I don't have that much time or incentive.
730 ERROR0 ("can't build a COFF file from scratch yet");
732 #ifdef MSDOS /* Demacs 1.1.1 91/10/16 HIRANO Satoshi */
733 bzero ((void *)&hdr
, sizeof hdr
);
735 bzero (&hdr
, sizeof hdr
);
740 unexec_text_start
= (long) start_of_text ();
741 unexec_data_start
= data_start
;
743 /* Machine-dependent fixup for header, or maybe for unexec_text_start */
744 #ifdef ADJUST_EXEC_HEADER
746 #endif /* ADJUST_EXEC_HEADER */
750 if (entry_address
!= 0)
751 hdr
.a_entry
= entry_address
;
753 hdr
.a_bss
= bss_end
- bss_start
;
754 hdr
.a_data
= bss_start
- data_start
;
756 hdr
.a_text
= ohdr
.a_text
;
757 #else /* not NO_REMAP */
758 hdr
.a_text
= data_start
- unexec_text_start
;
761 hdr
.a_text
+= A_TEXT_OFFSET (ohdr
);
764 #endif /* not NO_REMAP */
766 #ifdef COFF_ENCAPSULATE
767 /* We are encapsulating BSD format within COFF format. */
769 struct coffscn
*tp
, *dp
, *bp
;
770 tp
= &coffheader
.scns
[0];
771 dp
= &coffheader
.scns
[1];
772 bp
= &coffheader
.scns
[2];
773 tp
->s_size
= hdr
.a_text
+ sizeof(struct exec
);
774 dp
->s_paddr
= data_start
;
775 dp
->s_vaddr
= data_start
;
776 dp
->s_size
= hdr
.a_data
;
777 bp
->s_paddr
= dp
->s_vaddr
+ dp
->s_size
;
778 bp
->s_vaddr
= bp
->s_paddr
;
779 bp
->s_size
= hdr
.a_bss
;
780 coffheader
.tsize
= tp
->s_size
;
781 coffheader
.dsize
= dp
->s_size
;
782 coffheader
.bsize
= bp
->s_size
;
783 coffheader
.text_start
= tp
->s_vaddr
;
784 coffheader
.data_start
= dp
->s_vaddr
;
786 if (write (new, &coffheader
, sizeof coffheader
) != sizeof coffheader
)
790 #endif /* COFF_ENCAPSULATE */
792 if (write (new, &hdr
, sizeof hdr
) != sizeof hdr
)
797 #if 0 /* This #ifndef caused a bug on Linux when using QMAGIC. */
798 /* This adjustment was done above only #ifndef NO_REMAP,
799 so only undo it now #ifndef NO_REMAP. */
800 /* #ifndef NO_REMAP */
803 hdr
.a_text
-= A_TEXT_OFFSET (ohdr
);
808 #endif /* not COFF */
811 /* ****************************************************************
814 * Copy the text and data segments from memory to the new a.out
817 copy_text_and_data (new, a_out
)
825 #ifdef USG_SHARED_LIBRARIES
828 struct scnhdr scntemp
; /* Temporary section header */
830 /* The purpose of this code is to write out the new file's section
833 * Step through the section table. If we know the section (.text,
834 * .data) do the appropriate thing. Otherwise, if the section has
835 * no allocated space in the file (.bss), do nothing. Otherwise,
836 * the section has space allocated in the file, and is not a section
837 * we know. So just copy it.
840 lseek (a_out
, sizeof (struct filehdr
) + sizeof (struct aouthdr
), 0);
842 for (scns
= f_hdr
.f_nscns
; scns
> 0; scns
--)
844 if (read (a_out
, &scntemp
, sizeof (scntemp
)) != sizeof (scntemp
))
847 if (!strcmp (scntemp
.s_name
, ".text"))
849 lseek (new, (long) text_scnptr
, 0);
850 ptr
= (char *) f_ohdr
.text_start
;
851 end
= ptr
+ f_ohdr
.tsize
;
852 write_segment (new, ptr
, end
);
854 else if (!strcmp (scntemp
.s_name
, ".data"))
856 lseek (new, (long) data_scnptr
, 0);
857 ptr
= (char *) f_ohdr
.data_start
;
858 end
= ptr
+ f_ohdr
.dsize
;
859 write_segment (new, ptr
, end
);
861 else if (!scntemp
.s_scnptr
)
862 ; /* do nothing - no data for this section */
867 long old_a_out_ptr
= lseek (a_out
, 0, 1);
869 lseek (a_out
, scntemp
.s_scnptr
, 0);
870 for (size
= scntemp
.s_size
; size
> 0; size
-= sizeof (page
))
872 n
= size
> sizeof (page
) ? sizeof (page
) : size
;
873 if (read (a_out
, page
, n
) != n
|| write (new, page
, n
) != n
)
876 lseek (a_out
, old_a_out_ptr
, 0);
880 #else /* COFF, but not USG_SHARED_LIBRARIES */
884 /* Dump the original table of exception handlers, not the one
885 where our exception hooks are registered. */
886 __djgpp_exception_toggle ();
890 lseek (new, (long) text_scnptr
, 0);
891 ptr
= (char *) f_ohdr
.text_start
;
892 #ifdef HEADER_INCL_IN_TEXT
893 /* For Gould UTX/32, text starts after headers */
894 ptr
= (char *) (ptr
+ text_scnptr
);
895 #endif /* HEADER_INCL_IN_TEXT */
896 end
= ptr
+ f_ohdr
.tsize
;
897 write_segment (new, ptr
, end
);
899 lseek (new, (long) data_scnptr
, 0);
900 ptr
= (char *) f_ohdr
.data_start
;
901 end
= ptr
+ f_ohdr
.dsize
;
902 write_segment (new, ptr
, end
);
906 /* Restore our exception hooks. */
907 __djgpp_exception_toggle ();
911 #endif /* USG_SHARED_LIBRARIES */
913 #else /* if not COFF */
915 /* Some machines count the header as part of the text segment.
916 That is to say, the header appears in core
917 just before the address that start_of_text returns.
918 For them, N_TXTOFF is the place where the header goes.
919 We must adjust the seek to the place after the header.
920 Note that at this point hdr.a_text does *not* count
921 the extra A_TEXT_OFFSET bytes, only the actual bytes of code. */
924 lseek (new, (long) A_TEXT_SEEK (hdr
), 0);
926 lseek (new, (long) N_TXTOFF (hdr
), 0);
927 #endif /* no A_TEXT_SEEK */
931 /* Acorn's RISC-iX has a wacky way of initialising the position of the heap.
932 * There is a little table in crt0.o that is filled at link time with
933 * the min and current brk positions, among other things. When start
934 * runs, it copies the table to where these parameters live during
935 * execution. This data is in text space, so it cannot be modified here
936 * before saving the executable, so the data is written manually. In
937 * addition, the table does not have a label, and the nearest accessible
938 * label (mcount) is not prefixed with a '_', thus making it inaccessible
939 * from within C programs. To overcome this, emacs's executable is passed
940 * through the command 'nm %s | fgrep mcount' into a pipe, and the
941 * resultant output is then used to find the address of 'mcount'. As far as
942 * is possible to determine, in RISC-iX releases prior to 1.2, the negative
943 * offset of the table from mcount is 0x2c, whereas from 1.2 onwards it is
944 * 0x30. bss_end has been rounded up to page boundary. This solution is
945 * based on suggestions made by Kevin Welton and Steve Hunt of Acorn, and
946 * avoids the need for a custom version of crt0.o for emacs which has its
947 * table in data space.
953 char address_text
[32];
958 int mcount_address
, mcount_offset
, count
;
959 extern char *_execname
;
962 /* The use of _execname is incompatible with RISCiX 1.1 */
963 sprintf (command
, "nm %s | fgrep mcount", _execname
);
965 if ( (pfile
= popen(command
, "r")) == NULL
)
967 sprintf (errbuf
, "Could not open pipe");
972 while ( ((c
=getc(pfile
)) != EOF
) && (c
!= ' ') && (count
< 31))
973 address_text
[count
++]=c
;
974 address_text
[count
]=0;
976 if ((count
== 0) || pclose(pfile
) != NULL
)
978 sprintf (errbuf
, "Failed to execute the command '%s'\n", command
);
982 sscanf(address_text
, "%x", &mcount_address
);
983 ptr
= (char *) unexec_text_start
;
984 mcount_offset
= (char *)mcount_address
- ptr
;
987 #define EDATA_OFFSET 0x2c
989 #define EDATA_OFFSET 0x30
992 end
= ptr
+ mcount_offset
- EDATA_OFFSET
;
994 write_segment (new, ptr
, end
);
996 proforma
[0] = bss_end
; /* becomes _edata */
997 proforma
[1] = bss_end
; /* becomes _end */
998 proforma
[2] = bss_end
; /* becomes _minbrk */
999 proforma
[3] = bss_end
; /* becomes _curbrk */
1001 write (new, proforma
, 16);
1005 end
= temp_ptr
+ hdr
.a_text
;
1007 write_segment (new, ptr
, end
);
1011 ptr
= (char *) unexec_text_start
;
1012 end
= ptr
+ hdr
.a_text
;
1013 write_segment (new, ptr
, end
);
1016 ptr
= (char *) unexec_data_start
;
1017 end
= ptr
+ hdr
.a_data
;
1018 /* This lseek is certainly incorrect when A_TEXT_OFFSET
1019 and I believe it is a no-op otherwise.
1020 Let's see if its absence ever fails. */
1021 /* lseek (new, (long) N_TXTOFF (hdr) + hdr.a_text, 0); */
1022 write_segment (new, ptr
, end
);
1024 #endif /* not COFF */
1029 write_segment (new, ptr
, end
)
1031 register char *ptr
, *end
;
1033 register int i
, nwrite
, ret
;
1036 /* This is the normal amount to write at once.
1037 It is the size of block that NFS uses. */
1038 int writesize
= 1 << 13;
1039 int pagesize
= getpagesize ();
1040 char zeros
[1 << 13];
1042 bzero (zeros
, sizeof (zeros
));
1044 for (i
= 0; ptr
< end
;)
1046 /* Distance to next multiple of writesize. */
1047 nwrite
= (((int) ptr
+ writesize
) & -writesize
) - (int) ptr
;
1048 /* But not beyond specified end. */
1049 if (nwrite
> end
- ptr
) nwrite
= end
- ptr
;
1050 ret
= write (new, ptr
, nwrite
);
1051 /* If write gets a page fault, it means we reached
1052 a gap between the old text segment and the old data segment.
1053 This gap has probably been remapped into part of the text segment.
1054 So write zeros for it. */
1061 /* Write only a page of zeros at once,
1062 so that we we don't overshoot the start
1063 of the valid memory in the old data segment. */
1064 if (nwrite
> pagesize
)
1066 write (new, zeros
, nwrite
);
1068 #if 0 /* Now that we have can ask `write' to write more than a page,
1069 it is legit for write do less than the whole amount specified. */
1070 else if (nwrite
!= ret
)
1073 "unexec write failure: addr 0x%x, fileno %d, size 0x%x, wrote 0x%x, errno %d",
1074 ptr
, new, nwrite
, ret
, errno
);
1083 /* ****************************************************************
1086 * Copy the relocation information and symbol table from the a.out to the new
1089 copy_sym (new, a_out
, a_name
, new_name
)
1091 char *a_name
, *new_name
;
1100 if (SYMS_START
== 0L)
1105 if (lnnoptr
) /* if there is line number info */
1106 lseek (a_out
, lnnoptr
, 0); /* start copying from there */
1109 lseek (a_out
, SYMS_START
, 0); /* Position a.out to symtab. */
1111 while ((n
= read (a_out
, page
, sizeof page
)) > 0)
1113 if (write (new, page
, n
) != n
)
1125 /* ****************************************************************
1128 * After successfully building the new a.out, mark it executable
1136 int new = 0; /* for PERROR */
1140 if (stat (name
, &sbuf
) == -1)
1144 sbuf
.st_mode
|= 0111 & ~um
;
1145 if (chmod (name
, sbuf
.st_mode
) == -1)
1150 #ifndef COFF_BSD_SYMBOLS
1153 * If the COFF file contains a symbol table and a line number section,
1154 * then any auxiliary entries that have values for x_lnnoptr must
1155 * be adjusted by the amount that the line number section has moved
1156 * in the file (bias computed in make_hdr). The #@$%&* designers of
1157 * the auxiliary entry structures used the absolute file offsets for
1158 * the line number entry rather than an offset from the start of the
1159 * line number section!
1161 * When I figure out how to scan through the symbol table and pick out
1162 * the auxiliary entries that need adjustment, this routine will
1163 * be fixed. As it is now, all such entries are wrong and sdb
1164 * will complain. Fred Fish, UniSoft Systems Inc.
1167 /* This function is probably very slow. Instead of reopening the new
1168 file for input and output it should copy from the old to the new
1169 using the two descriptors already open (WRITEDESC and READDESC).
1170 Instead of reading one small structure at a time it should use
1171 a reasonable size buffer. But I don't have time to work on such
1172 things, so I am installing it as submitted to me. -- RMS. */
1174 adjust_lnnoptrs (writedesc
, readdesc
, new_name
)
1181 #if defined (amdahl_uts) || defined (pfa)
1185 struct syment symentry
;
1186 union auxent auxentry
;
1189 if (!lnnoptr
|| !f_hdr
.f_symptr
)
1193 if ((new = writedesc
) < 0)
1195 if ((new = open (new_name
, O_RDWR
)) < 0)
1202 lseek (new, f_hdr
.f_symptr
, 0);
1203 for (nsyms
= 0; nsyms
< f_hdr
.f_nsyms
; nsyms
++)
1205 read (new, &symentry
, SYMESZ
);
1206 if (symentry
.n_numaux
)
1208 read (new, &auxentry
, AUXESZ
);
1210 if (ISFCN (symentry
.n_type
) || symentry
.n_type
== 0x2400)
1212 auxentry
.x_sym
.x_fcnary
.x_fcn
.x_lnnoptr
+= bias
;
1213 lseek (new, -AUXESZ
, 1);
1214 write (new, &auxentry
, AUXESZ
);
1224 #endif /* COFF_BSD_SYMBOLS */
1228 #endif /* not CANNOT_DUMP */