1 /* Copyright (C) 1985, 1986, 1987, 1988, 1992, 1993, 1994
2 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 19.31. */
24 * unexec.c - Convert a running program into an a.out file.
26 * Author: Spencer W. Thomas
27 * Computer Science Dept.
29 * Date: Tue Mar 2 1982
30 * Modified heavily since then.
33 * unexec (new_name, a_name, data_start, bss_start, entry_address)
34 * char *new_name, *a_name;
35 * unsigned data_start, bss_start, entry_address;
37 * Takes a snapshot of the program and makes an a.out format file in the
38 * file named by the string argument new_name.
39 * If a_name is non-NULL, the symbol table will be taken from the given file.
40 * On some machines, an existing a_name file is required.
42 * The boundaries within the a.out file may be adjusted with the data_start
43 * and bss_start arguments. Either or both may be given as 0 for defaults.
45 * Data_start gives the boundary between the text segment and the data
46 * segment of the program. The text segment can contain shared, read-only
47 * program code and literal data, while the data segment is always unshared
48 * and unprotected. Data_start gives the lowest unprotected address.
49 * The value you specify may be rounded down to a suitable boundary
50 * as required by the machine you are using.
52 * Specifying zero for data_start means the boundary between text and data
53 * should not be the same as when the program was loaded.
54 * If NO_REMAP is defined, the argument data_start is ignored and the
55 * segment boundaries are never changed.
57 * Bss_start indicates how much of the data segment is to be saved in the
58 * a.out file and restored when the program is executed. It gives the lowest
59 * unsaved address, and is rounded up to a page boundary. The default when 0
60 * is given assumes that the entire data segment is to be stored, including
61 * the previous data and bss as well as any additional storage allocated with
64 * The new file is set up to start at entry_address.
66 * If you make improvements I'd like to get them too.
67 * harpo!utah-cs!thomas, thomas@Utah-20
71 /* Modified to support SysVr3 shared libraries by James Van Artsdalen
72 * of Dell Computer Corporation. james@bigtex.cactus.org.
75 /* There are several compilation parameters affecting unexec:
79 Define this if your system uses COFF for executables.
83 Define this if you are using the GNU coff encapsulated a.out format.
84 This is closer to a.out than COFF. You should *not* define COFF if
85 you define COFF_ENCAPSULATE
87 Otherwise we assume you use Berkeley format.
91 Define this if you do not want to try to save Emacs's pure data areas
92 as part of the text segment.
94 Saving them as text is good because it allows users to share more.
96 However, on machines that locate the text area far from the data area,
97 the boundary cannot feasibly be moved. Such machines require
100 Also, remapping can cause trouble with the built-in startup routine
101 /lib/crt0.o, which defines `environ' as an initialized variable.
102 Dumping `environ' as pure does not work! So, to use remapping,
103 you must write a startup routine for your machine in Emacs's crt0.c.
104 If NO_REMAP is defined, Emacs uses the system's crt0.o.
108 Some machines that use COFF executables require that each section
109 start on a certain boundary *in the COFF file*. Such machines should
110 define SECTION_ALIGNMENT to a mask of the low-order bits that must be
111 zero on such a boundary. This mask is used to control padding between
112 segments in the COFF file.
114 If SECTION_ALIGNMENT is not defined, the segments are written
115 consecutively with no attempt at alignment. This is right for
120 Some machines require that the beginnings and ends of segments
121 *in core* be on certain boundaries. For most machines, a page
122 boundary is sufficient. That is the default. When a larger
123 boundary is needed, define SEGMENT_MASK to a mask of
124 the bits that must be zero on such a boundary.
128 Some machines count the a.out header as part of the size of the text
129 segment (a_text); they may actually load the header into core as the
130 first data in the text segment. Some have additional padding between
131 the header and the real text of the program that is counted in a_text.
133 For these machines, define A_TEXT_OFFSET(HDR) to examine the header
134 structure HDR and return the number of bytes to add to `a_text'
135 before writing it (above and beyond the number of bytes of actual
136 program text). HDR's standard fields are already correct, except that
137 this adjustment to the `a_text' field has not yet been made;
138 thus, the amount of offset can depend on the data in the file.
142 If defined, this macro specifies the number of bytes to seek into the
143 a.out file before starting to write the text segment.
147 For machines using COFF, this macro, if defined, is a value stored
148 into the magic number field of the output file.
152 This macro can be used to generate statements to adjust or
153 initialize nonstandard fields in the file header
157 Macro to correct an int which is the bit pattern of a pointer to a byte
158 into an int which is the number of a byte.
160 This macro has a default definition which is usually right.
161 This default definition is a no-op on most machines (where a
162 pointer looks like an int) but not on all machines.
167 #define PERROR(arg) perror (arg); return -1
170 #define DONT_ENCAPSULATE /* we include lisp.h so we want to make sure we
171 don't get filename conversion. The caller
172 of unexec() is assumed to have done this
173 already (it's easier to do it this way than
174 to modify all the unexec modules to ensure
175 that all weirdo functions, such as
176 elf_write_modified_data(), have proper
177 filename conversion applied). */
179 #define PERROR(file) report_error (file, new)
182 #if __STDC__ || defined(STDC_HEADERS)
184 /* I don't know how correct this attempt to get more prototypes is... */
185 # if defined(sun) && defined(_POSIX_SOURCE)
186 # undef _POSIX_SOURCE
198 /* I don't understand this, but it's necessary to get some slots in struct exec
199 from /usr/include/sys/exec.h when running LCC in strict ANSI mode. We don't
200 need this in K&R mode...
202 #if defined(__lucid) && defined(__sparc) && !defined(sun)
206 #ifndef CANNOT_DUMP /* all rest of file! */
208 #ifdef COFF_ENCAPSULATE
209 int need_coff_header = 1;
210 #include <coff-encap/a.out.encap.h> /* The location might be a poor assumption */
214 #include <fcntl.h> /* for O_RDONLY, O_RDWR */
217 #define filehdr external_filehdr
218 #define scnhdr external_scnhdr
219 #define syment external_syment
220 #define auxent external_auxent
221 #define n_numaux e_numaux
222 #define n_type e_type
225 unsigned short magic; /* type of file */
226 unsigned short vstamp; /* version stamp */
227 unsigned long tsize; /* text size in bytes, padded to FW bdry*/
228 unsigned long dsize; /* initialized data " " */
229 unsigned long bsize; /* uninitialized data " " */
230 unsigned long entry; /* entry pt. */
231 unsigned long text_start;/* base of text used for this file */
232 unsigned long data_start;/* base of data used for this file */
236 #else /* not MSDOS */
238 #endif /* not MSDOS */
239 #endif /* not COFF_ENCAPSULATE */
241 /* Define getpagesize if the system does not.
242 Note that this may depend on symbols defined in a.out.h. */
243 #include "getpagesize.h"
245 #ifndef makedev /* Try to detect types.h already loaded */
246 #include <sys/types.h>
249 #include <sys/stat.h>
252 #include <sys/file.h> /* Must be after sys/types.h for USG and BSD4_1*/
266 extern char *start_of_text (); /* Start of text */
268 extern void *start_of_data (); /* Start of initialized data */
271 static long block_copy_start; /* Old executable start point */
272 static struct filehdr f_hdr; /* File header */
273 static struct aouthdr f_ohdr; /* Optional file header (a.out) */
274 long bias; /* Bias to add for growth */
275 long lnnoptr; /* Pointer to line-number info within file */
276 #define SYMS_START block_copy_start
278 static long text_scnptr;
279 static long data_scnptr;
284 #ifndef __sys_stdtypes_h
285 #if !defined(_PTRDIFF_T) && !defined(_BSD_PTRDIFF_T_)
286 typedef long ptrdiff_t;
290 /* not sure where this for NetBSD should really go
291 and it probably applies to other systems */
292 #if !defined(__NetBSD__) && !defined(__bsdi__) && !defined(__OpenBSD__)
293 extern void *sbrk (ptrdiff_t);
295 extern char *sbrk ();
296 #endif /* __NetBSD__ or __OpenBSD__ */
299 extern void *sbrk ();
302 #define SYMS_START ((long) N_SYMOFF (ohdr))
304 /* Some machines override the structure name for an a.out header. */
305 #ifndef EXEC_HDR_TYPE
306 #define EXEC_HDR_TYPE struct exec
311 #define MY_ID HP9000S200_ID
315 #endif /* no HP9000S200_ID */
316 static MAGIC OLDMAGIC = {MY_ID, SHARE_MAGIC};
317 static MAGIC NEWMAGIC = {MY_ID, DEMAND_MAGIC};
318 #define N_TXTOFF(x) TEXT_OFFSET(x)
319 #define N_SYMOFF(x) LESYM_OFFSET(x)
320 static EXEC_HDR_TYPE hdr, ohdr;
324 #if defined (USG) && !defined (IBMAIX) && !defined (IRIS) && !defined (COFF_ENCAPSULATE) && !defined (LINUX)
325 static struct bhdr hdr, ohdr;
326 #define a_magic fmagic
331 #define a_trsize rtsize
332 #define a_drsize rdsize
333 #define a_entry entry
334 #define N_BADMAG(x) \
335 (((x).fmagic)!=OMAGIC && ((x).fmagic)!=NMAGIC &&\
336 ((x).fmagic)!=FMAGIC && ((x).fmagic)!=IMAGIC)
337 #define NEWMAGIC FMAGIC
338 #else /* IRIS or IBMAIX or not USG */
339 static EXEC_HDR_TYPE hdr, ohdr;
340 #define NEWMAGIC ZMAGIC
341 #endif /* IRIS or IBMAIX not USG */
342 #endif /* not HPUX */
344 static int unexec_text_start;
345 static int unexec_data_start;
347 #ifdef COFF_ENCAPSULATE
348 /* coffheader is defined in the GNU a.out.encap.h file. */
349 struct coffheader coffheader;
352 #endif /* not COFF */
356 /* Correct an int which is the bit pattern of a pointer to a byte
357 into an int which is the number of a byte.
358 This is a no-op on ordinary machines, but not on all. */
360 #ifndef ADDR_CORRECT /* Let m-*.h files override this definition */
361 #define ADDR_CORRECT(x) ((char *)(x) - (char*)0)
369 report_error (file, fd)
375 report_file_error ("Cannot unexec",
376 Fcons (build_ext_string (file, FORMAT_FILENAME), Qnil));
380 #define ERROR0(msg) report_error_1 (new, msg, 0, 0); return -1
381 #define ERROR1(msg,x) report_error_1 (new, msg, x, 0); return -1
382 #define ERROR2(msg,x,y) report_error_1 (new, msg, x, y); return -1
385 report_error_1 (fd, msg, a1, a2)
394 fprintf (stderr, msg, a1, a2);
395 fprintf (stderr, "\n");
399 static int make_hdr (int new, int a_out, unsigned data_start,
400 unsigned bss_start, unsigned entry_address,
401 char *a_name, char *new_name);
402 static int copy_text_and_data (int new, int a_out);
403 static int copy_sym (int new, int a_out, char *a_name, char *new_name);
404 static void mark_x (char *name);
406 /* ****************************************************************
412 unexec (new_name, a_name, data_start, bss_start, entry_address)
413 char *new_name, *a_name;
414 unsigned data_start, bss_start, entry_address;
418 if (a_name && (a_out = open (a_name, O_RDONLY)) < 0)
422 if ((new = creat (new_name, 0666)) < 0)
427 if (make_hdr (new, a_out, data_start, bss_start, entry_address, a_name, new_name) < 0
428 || copy_text_and_data (new, a_out) < 0
429 || copy_sym (new, a_out, a_name, new_name) < 0
431 #ifndef COFF_BSD_SYMBOLS
432 || adjust_lnnoptrs (new, a_out, new_name) < 0
438 /* unlink (new_name); / * Failed, unlink new a.out */
449 /* ****************************************************************
452 * Make the header in the new a.out from the header in core.
453 * Modify the text and data sizes.
456 make_hdr (int new, int a_out, unsigned data_start, unsigned bss_start,
457 unsigned entry_address, char *a_name, char *new_name)
460 auto struct scnhdr f_thdr; /* Text section header */
461 auto struct scnhdr f_dhdr; /* Data section header */
462 auto struct scnhdr f_bhdr; /* Bss section header */
463 auto struct scnhdr scntemp; /* Temporary section header */
466 #ifdef USG_SHARED_LIBRARIES
467 extern unsigned int bss_end;
469 unsigned int bss_end;
472 pagemask = getpagesize () - 1;
474 /* Adjust text/data boundary. */
476 data_start = (int) start_of_data ();
477 #else /* not NO_REMAP */
479 data_start = (int) start_of_data ();
480 #endif /* not NO_REMAP */
481 data_start = ADDR_CORRECT (data_start);
484 data_start = data_start & ~SEGMENT_MASK; /* (Down) to segment boundary. */
486 data_start = data_start & ~pagemask; /* (Down) to page boundary. */
489 bss_end = ADDR_CORRECT (sbrk (0)) + pagemask;
490 bss_end &= ~ pagemask;
492 /* Adjust data/bss boundary. */
495 bss_start = (ADDR_CORRECT (bss_start) + pagemask);
496 /* (Up) to page bdry. */
497 bss_start &= ~ pagemask;
498 if (bss_start > bss_end)
500 ERROR1 ("unexec: Specified bss_start (%u) is past end of program",
507 if (data_start > bss_start) /* Can't have negative data size. */
509 ERROR2 ("unexec: data_start (%u) can't be greater than bss_start (%u)",
510 data_start, bss_start);
514 /* Salvage as much info from the existing file as possible */
517 if (read (a_out, &f_hdr, sizeof (f_hdr)) != sizeof (f_hdr))
521 block_copy_start += sizeof (f_hdr);
522 if (f_hdr.f_opthdr > 0)
524 if (read (a_out, &f_ohdr, sizeof (f_ohdr)) != sizeof (f_ohdr))
528 block_copy_start += sizeof (f_ohdr);
530 /* Loop through section headers, copying them in */
531 lseek (a_out, sizeof (f_hdr) + f_hdr.f_opthdr, 0);
532 for (scns = f_hdr.f_nscns; scns > 0; scns--) {
533 if (read (a_out, &scntemp, sizeof (scntemp)) != sizeof (scntemp))
537 if (scntemp.s_scnptr > 0L)
539 if (block_copy_start < scntemp.s_scnptr + scntemp.s_size)
540 block_copy_start = scntemp.s_scnptr + scntemp.s_size;
542 if (strcmp (scntemp.s_name, ".text") == 0)
546 else if (strcmp (scntemp.s_name, ".data") == 0)
550 else if (strcmp (scntemp.s_name, ".bss") == 0)
558 ERROR0 ("can't build a COFF file from scratch yet");
561 /* Now we alter the contents of all the f_*hdr variables
562 to correspond to what we want to dump. */
564 #ifdef USG_SHARED_LIBRARIES
566 /* The amount of data we're adding to the file is distance from the
567 * end of the original .data space to the current end of the .data
571 bias = bss_start - (f_ohdr.data_start + f_dhdr.s_size);
575 f_hdr.f_flags |= (F_RELFLG | F_EXEC);
580 f_ohdr.magic = EXEC_MAGIC;
583 f_ohdr.text_start = (long) start_of_text ();
584 f_ohdr.tsize = data_start - f_ohdr.text_start;
585 f_ohdr.data_start = data_start;
586 #endif /* NO_REMAP */
587 f_ohdr.dsize = bss_start - f_ohdr.data_start;
588 f_ohdr.bsize = bss_end - bss_start;
589 #ifndef KEEP_OLD_TEXT_SCNPTR
590 /* On some machines, the old values are right.
591 ??? Maybe on all machines with NO_REMAP. */
592 f_thdr.s_size = f_ohdr.tsize;
593 f_thdr.s_scnptr = sizeof (f_hdr) + sizeof (f_ohdr);
594 f_thdr.s_scnptr += (f_hdr.f_nscns) * (sizeof (f_thdr));
595 #endif /* KEEP_OLD_TEXT_SCNPTR */
596 #ifdef ADJUST_TEXT_SCNHDR_SIZE
597 /* On some machines, `text size' includes all headers. */
598 f_thdr.s_size -= f_thdr.s_scnptr;
599 #endif /* ADJUST_TEST_SCNHDR_SIZE */
600 lnnoptr = f_thdr.s_lnnoptr;
601 #ifdef SECTION_ALIGNMENT
602 /* Some systems require special alignment
603 of the sections in the file itself. */
605 = (f_thdr.s_scnptr + SECTION_ALIGNMENT) & ~SECTION_ALIGNMENT;
606 #endif /* SECTION_ALIGNMENT */
608 f_thdr.s_scnptr = 0xd0;
610 text_scnptr = f_thdr.s_scnptr;
611 #ifdef ADJUST_TEXTBASE
612 text_scnptr = sizeof (f_hdr) + sizeof (f_ohdr) + (f_hdr.f_nscns) * (sizeof (f_thdr));
614 #ifndef KEEP_OLD_PADDR
615 f_dhdr.s_paddr = f_ohdr.data_start;
616 #endif /* KEEP_OLD_PADDR */
617 f_dhdr.s_vaddr = f_ohdr.data_start;
618 f_dhdr.s_size = f_ohdr.dsize;
619 f_dhdr.s_scnptr = f_thdr.s_scnptr + f_thdr.s_size;
620 #ifdef SECTION_ALIGNMENT
621 /* Some systems require special alignment
622 of the sections in the file itself. */
624 = (f_dhdr.s_scnptr + SECTION_ALIGNMENT) & ~SECTION_ALIGNMENT;
625 #endif /* SECTION_ALIGNMENT */
626 #ifdef DATA_SECTION_ALIGNMENT
627 /* Some systems require special alignment
628 of the data section only. */
630 = (f_dhdr.s_scnptr + DATA_SECTION_ALIGNMENT) & ~DATA_SECTION_ALIGNMENT;
631 #endif /* DATA_SECTION_ALIGNMENT */
632 data_scnptr = f_dhdr.s_scnptr;
633 #ifndef KEEP_OLD_PADDR
634 f_bhdr.s_paddr = f_ohdr.data_start + f_ohdr.dsize;
635 #endif /* KEEP_OLD_PADDR */
636 f_bhdr.s_vaddr = f_ohdr.data_start + f_ohdr.dsize;
637 f_bhdr.s_size = f_ohdr.bsize;
638 f_bhdr.s_scnptr = 0L;
639 #ifndef USG_SHARED_LIBRARIES
640 bias = f_dhdr.s_scnptr + f_dhdr.s_size - block_copy_start;
643 if (f_hdr.f_symptr > 0L)
645 f_hdr.f_symptr += bias;
648 if (f_thdr.s_lnnoptr > 0L)
650 f_thdr.s_lnnoptr += bias;
653 #ifdef ADJUST_EXEC_HEADER
655 #endif /* ADJUST_EXEC_HEADER */
657 if (write (new, &f_hdr, sizeof (f_hdr)) != sizeof (f_hdr))
662 if (write (new, &f_ohdr, sizeof (f_ohdr)) != sizeof (f_ohdr))
667 #ifndef USG_SHARED_LIBRARIES
669 if (write (new, &f_thdr, sizeof (f_thdr)) != sizeof (f_thdr))
674 if (write (new, &f_dhdr, sizeof (f_dhdr)) != sizeof (f_dhdr))
679 if (write (new, &f_bhdr, sizeof (f_bhdr)) != sizeof (f_bhdr))
684 #else /* USG_SHARED_LIBRARIES */
686 /* The purpose of this code is to write out the new file's section
689 * Scan through the original file's sections. If the encountered
690 * section is one we know (.text, .data or .bss), write out the
691 * correct header. If it is a section we do not know (such as
692 * .lib), adjust the address of where the section data is in the
693 * file, and write out the header.
695 * If any section precedes .text or .data in the file, this code
696 * will not adjust the file pointer for that section correctly.
699 /* This used to use sizeof (f_ohdr) instead of .f_opthdr.
700 .f_opthdr is said to be right when there is no optional header. */
701 lseek (a_out, sizeof (f_hdr) + f_hdr.f_opthdr, 0);
703 for (scns = f_hdr.f_nscns; scns > 0; scns--)
705 if (read (a_out, &scntemp, sizeof (scntemp)) != sizeof (scntemp))
708 if (!strcmp (scntemp.s_name, f_thdr.s_name)) /* .text */
710 if (write (new, &f_thdr, sizeof (f_thdr)) != sizeof (f_thdr))
713 else if (!strcmp (scntemp.s_name, f_dhdr.s_name)) /* .data */
715 if (write (new, &f_dhdr, sizeof (f_dhdr)) != sizeof (f_dhdr))
718 else if (!strcmp (scntemp.s_name, f_bhdr.s_name)) /* .bss */
720 if (write (new, &f_bhdr, sizeof (f_bhdr)) != sizeof (f_bhdr))
725 if (scntemp.s_scnptr)
726 scntemp.s_scnptr += bias;
727 if (write (new, &scntemp, sizeof (scntemp)) != sizeof (scntemp))
731 #endif /* USG_SHARED_LIBRARIES */
735 #else /* if not COFF */
737 /* Get symbol table info from header of a.out file if given one. */
740 #ifdef COFF_ENCAPSULATE
741 if (read (a_out, &coffheader, sizeof coffheader) != sizeof coffheader)
745 if (coffheader.f_magic != COFF_MAGIC)
747 ERROR1("%s doesn't have legal coff magic number\n", a_name);
750 if (read (a_out, (char *) &ohdr, sizeof hdr) != sizeof hdr)
757 ERROR1 ("invalid magic number in %s", a_name);
763 #ifdef COFF_ENCAPSULATE
764 /* We probably could without too much trouble. The code is in gld
765 * but I don't have that much time or incentive.
767 ERROR0 ("can't build a COFF file from scratch yet");
769 memset ((void *)&hdr, 0, sizeof hdr);
773 unexec_text_start = (long) start_of_text ();
774 unexec_data_start = data_start;
776 /* Machine-dependent fixup for header, or maybe for unexec_text_start */
777 #ifdef ADJUST_EXEC_HEADER
779 #endif /* ADJUST_EXEC_HEADER */
783 if (entry_address != 0)
784 hdr.a_entry = entry_address;
786 hdr.a_bss = bss_end - bss_start;
787 hdr.a_data = bss_start - data_start;
789 hdr.a_text = ohdr.a_text;
790 #else /* not NO_REMAP */
791 hdr.a_text = data_start - unexec_text_start;
794 hdr.a_text += A_TEXT_OFFSET (ohdr);
797 #endif /* not NO_REMAP */
799 #ifdef COFF_ENCAPSULATE
800 /* We are encapsulating BSD format within COFF format. */
802 struct coffscn *tp, *dp, *bp;
803 tp = &coffheader.scns[0];
804 dp = &coffheader.scns[1];
805 bp = &coffheader.scns[2];
806 tp->s_size = hdr.a_text + sizeof(struct exec);
807 dp->s_paddr = data_start;
808 dp->s_vaddr = data_start;
809 dp->s_size = hdr.a_data;
810 bp->s_paddr = dp->s_vaddr + dp->s_size;
811 bp->s_vaddr = bp->s_paddr;
812 bp->s_size = hdr.a_bss;
813 coffheader.tsize = tp->s_size;
814 coffheader.dsize = dp->s_size;
815 coffheader.bsize = bp->s_size;
816 coffheader.text_start = tp->s_vaddr;
817 coffheader.data_start = dp->s_vaddr;
819 if (write (new, &coffheader, sizeof coffheader) != sizeof coffheader)
823 #endif /* COFF_ENCAPSULATE */
825 if (write (new, (char *) &hdr, sizeof hdr) != sizeof hdr)
830 #if 0 /* This #ifndef caused a bug on Linux when using QMAGIC. */
831 /* This adjustment was done above only #ifndef NO_REMAP,
832 so only undo it now #ifndef NO_REMAP. */
833 /* #ifndef NO_REMAP */
836 hdr.a_text -= A_TEXT_OFFSET (ohdr);
841 #endif /* not COFF */
844 static void write_segment (int, char *, char *);
846 /* ****************************************************************
849 * Copy the text and data segments from memory to the new a.out
852 copy_text_and_data (int new, int a_out)
859 #ifdef USG_SHARED_LIBRARIES
862 struct scnhdr scntemp; /* Temporary section header */
864 /* The purpose of this code is to write out the new file's section
867 * Step through the section table. If we know the section (.text,
868 * .data) do the appropriate thing. Otherwise, if the section has
869 * no allocated space in the file (.bss), do nothing. Otherwise,
870 * the section has space allocated in the file, and is not a section
871 * we know. So just copy it.
874 lseek (a_out, sizeof (struct filehdr) + sizeof (struct aouthdr), 0);
876 for (scns = f_hdr.f_nscns; scns > 0; scns--)
878 if (read (a_out, &scntemp, sizeof (scntemp)) != sizeof (scntemp))
881 if (!strcmp (scntemp.s_name, ".text"))
883 lseek (new, (long) text_scnptr, 0);
884 ptr = (char *) f_ohdr.text_start;
885 end = ptr + f_ohdr.tsize;
886 write_segment (new, ptr, end);
888 else if (!strcmp (scntemp.s_name, ".data"))
890 lseek (new, (long) data_scnptr, 0);
891 ptr = (char *) f_ohdr.data_start;
892 end = ptr + f_ohdr.dsize;
893 write_segment (new, ptr, end);
895 else if (!scntemp.s_scnptr)
896 ; /* do nothing - no data for this section */
901 long old_a_out_ptr = lseek (a_out, 0, 1);
903 lseek (a_out, scntemp.s_scnptr, 0);
904 for (size = scntemp.s_size; size > 0; size -= sizeof (page))
906 n = size > sizeof (page) ? sizeof (page) : size;
907 if (read (a_out, page, n) != n || write (new, page, n) != n)
910 lseek (a_out, old_a_out_ptr, 0);
914 #else /* COFF, but not USG_SHARED_LIBRARIES */
918 /* Dump the original table of exception handlers, not the one
919 where our exception hooks are registered. */
920 __djgpp_exception_toggle ();
924 lseek (new, (long) text_scnptr, 0);
925 ptr = (char *) f_ohdr.text_start;
926 #ifdef HEADER_INCL_IN_TEXT
927 /* For Gould UTX/32, text starts after headers */
928 ptr = (char *) (ptr + text_scnptr);
929 #endif /* HEADER_INCL_IN_TEXT */
930 end = ptr + f_ohdr.tsize;
931 write_segment (new, ptr, end);
933 lseek (new, (long) data_scnptr, 0);
934 ptr = (char *) f_ohdr.data_start;
935 end = ptr + f_ohdr.dsize;
936 write_segment (new, ptr, end);
940 /* Restore our exception hooks. */
941 __djgpp_exception_toggle ();
945 #endif /* USG_SHARED_LIBRARIES */
947 #else /* if not COFF */
949 /* Some machines count the header as part of the text segment.
950 That is to say, the header appears in core
951 just before the address that start_of_text returns.
952 For them, N_TXTOFF is the place where the header goes.
953 We must adjust the seek to the place after the header.
954 Note that at this point hdr.a_text does *not* count
955 the extra A_TEXT_OFFSET bytes, only the actual bytes of code. */
958 lseek (new, (long) A_TEXT_SEEK (hdr), 0);
960 lseek (new, (long) N_TXTOFF (hdr), 0);
961 #endif /* no A_TEXT_SEEK */
965 /* Acorn's RISC-iX has a wacky way of initializing the position of the heap.
966 * There is a little table in crt0.o that is filled at link time with
967 * the min and current brk positions, among other things. When start
968 * runs, it copies the table to where these parameters live during
969 * execution. This data is in text space, so it cannot be modified here
970 * before saving the executable, so the data is written manually. In
971 * addition, the table does not have a label, and the nearest accessible
972 * label (mcount) is not prefixed with a '_', thus making it inaccessible
973 * from within C programs. To overcome this, emacs's executable is passed
974 * through the command 'nm %s | fgrep mcount' into a pipe, and the
975 * resultant output is then used to find the address of 'mcount'. As far as
976 * is possible to determine, in RISC-iX releases prior to 1.2, the negative
977 * offset of the table from mcount is 0x2c, whereas from 1.2 onwards it is
978 * 0x30. bss_end has been rounded up to page boundary. This solution is
979 * based on suggestions made by Kevin Welton and Steve Hunt of Acorn, and
980 * avoids the need for a custom version of crt0.o for emacs which has its
981 * table in data space.
987 char address_text[32];
992 int mcount_address, mcount_offset, count;
993 extern char *_execname;
996 /* The use of _execname is incompatible with RISCiX 1.1 */
997 sprintf (command, "nm %s | fgrep mcount", _execname);
999 if ( (pfile = popen(command, "r")) == NULL)
1001 sprintf (errbuf, "Could not open pipe");
1006 while ( ((c=getc(pfile)) != EOF) && (c != ' ') && (count < 31))
1007 address_text[count++]=c;
1008 address_text[count]=0;
1010 if ((count == 0) || pclose(pfile) != NULL)
1012 sprintf (errbuf, "Failed to execute the command '%s'\n", command);
1016 sscanf(address_text, "%x", &mcount_address);
1017 ptr = (char *) unexec_text_start;
1018 mcount_offset = (char *)mcount_address - ptr;
1021 #define EDATA_OFFSET 0x2c
1023 #define EDATA_OFFSET 0x30
1026 end = ptr + mcount_offset - EDATA_OFFSET;
1028 write_segment (new, ptr, end);
1030 proforma[0] = bss_end; /* becomes _edata */
1031 proforma[1] = bss_end; /* becomes _end */
1032 proforma[2] = bss_end; /* becomes _minbrk */
1033 proforma[3] = bss_end; /* becomes _curbrk */
1035 write (new, proforma, 16);
1039 end = temp_ptr + hdr.a_text;
1041 write_segment (new, ptr, end);
1045 ptr = (char *) unexec_text_start;
1046 end = ptr + hdr.a_text;
1047 write_segment (new, ptr, end);
1050 ptr = (char *) unexec_data_start;
1051 end = ptr + hdr.a_data;
1052 /* This lseek is certainly incorrect when A_TEXT_OFFSET
1053 and I believe it is a no-op otherwise.
1054 Let's see if its absence ever fails. */
1055 /* lseek (new, (long) N_TXTOFF (hdr) + hdr.a_text, 0); */
1056 write_segment (new, ptr, end);
1058 #endif /* not COFF */
1064 write_segment (new, ptr, end)
1072 /* This is the normal amount to write at once.
1073 It is the size of block that NFS uses. */
1074 int writesize = 1 << 13;
1075 int pagesize = getpagesize ();
1076 char zeros[1 << 13];
1078 memset (zeros, 0, sizeof (zeros));
1080 for (i = 0; ptr < end;)
1082 /* Distance to next multiple of writesize. */
1083 nwrite = (((int) ptr + writesize) & -writesize) - (int) ptr;
1084 /* But not beyond specified end. */
1085 if (nwrite > end - ptr) nwrite = end - ptr;
1086 ret = write (new, ptr, nwrite);
1087 /* If write gets a page fault, it means we reached
1088 a gap between the old text segment and the old data segment.
1089 This gap has probably been remapped into part of the text segment.
1090 So write zeros for it. */
1097 /* Write only a page of zeros at once,
1098 so that we don't overshoot the start
1099 of the valid memory in the old data segment. */
1100 if (nwrite > pagesize)
1102 write (new, zeros, nwrite);
1104 #if 0 /* Now that we have can ask `write' to write more than a page,
1105 it is legit for write do less than the whole amount specified. */
1106 else if (nwrite != ret)
1109 "unexec write failure: addr 0x%lx, fileno %d, size 0x%x, wrote 0x%x, errno %d",
1110 (unsigned long) ptr, new, nwrite, ret, errno);
1119 /* ****************************************************************
1122 * Copy the relocation information and symbol table from the a.out to the new
1125 copy_sym (int new, int a_out, char *a_name, char *new_name)
1134 if (SYMS_START == 0L)
1139 if (lnnoptr) /* if there is line number info */
1140 lseek (a_out, lnnoptr, 0); /* start copying from there */
1143 lseek (a_out, SYMS_START, 0); /* Position a.out to symtab. */
1145 while ((n = read (a_out, page, sizeof page)) > 0)
1147 if (write (new, page, n) != n)
1159 /* ****************************************************************
1162 * After successfully building the new a.out, mark it executable
1169 int new = 0; /* for PERROR */
1173 if (stat (name, &sbuf) == -1)
1177 sbuf.st_mode |= 0111 & ~um;
1178 if (chmod (name, sbuf.st_mode) == -1)
1183 #ifndef COFF_BSD_SYMBOLS
1186 * If the COFF file contains a symbol table and a line number section,
1187 * then any auxiliary entries that have values for x_lnnoptr must
1188 * be adjusted by the amount that the line number section has moved
1189 * in the file (bias computed in make_hdr). The #@$%&* designers of
1190 * the auxiliary entry structures used the absolute file offsets for
1191 * the line number entry rather than an offset from the start of the
1192 * line number section!
1194 * When I figure out how to scan through the symbol table and pick out
1195 * the auxiliary entries that need adjustment, this routine will
1196 * be fixed. As it is now, all such entries are wrong and sdb
1197 * will complain. Fred Fish, UniSoft Systems Inc.
1200 /* This function is probably very slow. Instead of reopening the new
1201 file for input and output it should copy from the old to the new
1202 using the two descriptors already open (WRITEDESC and READDESC).
1203 Instead of reading one small structure at a time it should use
1204 a reasonable size buffer. But I don't have time to work on such
1205 things, so I am installing it as submitted to me. -- RMS. */
1208 adjust_lnnoptrs (writedesc, readdesc, new_name)
1215 #if defined (amdahl_uts) || defined (pfa)
1219 struct syment symentry;
1220 union auxent auxentry;
1223 if (!lnnoptr || !f_hdr.f_symptr)
1227 if ((new = writedesc) < 0)
1229 if ((new = open (new_name, O_RDWR)) < 0)
1236 lseek (new, f_hdr.f_symptr, 0);
1237 for (nsyms = 0; nsyms < f_hdr.f_nsyms; nsyms++)
1239 read (new, &symentry, SYMESZ);
1240 if (symentry.n_numaux)
1242 read (new, &auxentry, AUXESZ);
1244 if (ISFCN (symentry.n_type) || symentry.n_type == 0x2400)
1246 auxentry.x_sym.x_fcnary.x_fcn.x_lnnoptr += bias;
1247 lseek (new, -AUXESZ, 1);
1248 write (new, &auxentry, AUXESZ);
1258 #endif /* COFF_BSD_SYMBOLS */
1262 #endif /* not CANNOT_DUMP */