--- /dev/null
+/* Copyright (C) 1985, 1986, 1987, 1988, 1990, 1992, 1999, 2000
+ Free Software Foundation, Inc.
+
+ This file is part of XEmacs.
+
+ XEmacs is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+
+ GNU Emacs is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with GNU Emacs; see the file COPYING. If not, write to the
+ Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA.
+
+ In other words, you are welcome to use, share and improve this
+ program. You are forbidden to forbid anyone else to use, share and
+ improve what you give them. Help stamp out software-hoarding! */
+
+
+/*
+ * unexec.c - Convert a running program into an a.out file.
+ *
+ * Author: Spencer W. Thomas
+ * Computer Science Dept.
+ * University of Utah
+ * Date: Tue Mar 2 1982
+ * Modified heavily since then.
+ *
+ * Synopsis:
+ * void
+ * unexec (char *new_name,
+ * char *old_name,
+ * uintptr_t data_start,
+ * uintptr_t bss_start,
+ * uintptr_t entry_address)
+ *
+ * The basic idea is that we start with an ELF file which contains
+ * .bss (uninitialized global data) section which is normally not in
+ * the file. As we load lisp the variables, which were first set to 0,
+ * will change their values. We want to save those changed values into
+ * another ELF file, which will become a new xemacs image. To do this,
+ * we need to change several structures in the ELF file.
+ *
+ * First of all, we need to change the programm header which tells
+ * the linker how to load stuff into memory so that data will come
+ * from the file and not from the /dev/zero. To do this, we find the
+ * segment, which is marked as loadable (type PT_LOAD) and which
+ * covers the old .bss section. We will next change the filesz and
+ * memsz for that segment to extend over the new data section.
+ *
+ * Next we have to make sure that section header for the stuff which
+ * used to be uninitialized is changed to be initialized and to come
+ * from the file. To do this, we change the size and the type of the old
+ * .bss section (and all other section of the type SHT_NOBITS) to cover the
+ * new section and to be of type SHT_PROCBITS.
+ *
+ * We also insert a new SHT_NOBITS section to keep some tools, which expect
+ * .bss happy.
+ *
+ * Finally we need to patch up some references to the section
+ * indexes since we change the order and undo the relocation info to
+ * be the same as it was "before" because we actually used the data
+ * from the memory which were changed by the run-time linker.
+ */
+\f
+#ifndef emacs
+#define fatal(a, b, c) fprintf (stderr, a, b, c), exit (1)
+#include <string.h>
+#else
+#include <config.h>
+extern void fatal (const char *, ...);
+#endif
+
+#include <sys/types.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <memory.h>
+#include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
+#ifdef HAVE_ELF_H
+#include <elf.h>
+#endif
+#include <sys/mman.h>
+#if defined (__sony_news) && defined (_SYSTYPE_SYSV)
+#include <sys/elf_mips.h>
+#include <sym.h>
+#endif /* __sony_news && _SYSTYPE_SYSV */
+#if __sgi
+#include <syms.h> /* for HDRR declaration */
+#endif /* __sgi */
+
+#if __GNU_LIBRARY__ - 0 >= 6
+# include <link.h> /* get ElfW etc */
+#endif
+
+#ifndef ElfW
+# ifdef __STDC__
+# define ElfBitsW(bits, type) Elf##bits##_##type
+# else
+# define ElfBitsW(bits, type) Elf/**/bits/**/_/**/type
+# endif
+# ifdef _LP64
+# define ELFSIZE 64
+# else
+# define ELFSIZE 32
+# endif
+ /* This macro expands `bits' before invoking ElfBitsW. */
+# define ElfExpandBitsW(bits, type) ElfBitsW (bits, type)
+# define ElfW(type) ElfExpandBitsW (ELFSIZE, type)
+#endif
+
+#ifndef ELF_BSS_SECTION_NAME
+#define ELF_BSS_SECTION_NAME ".bss"
+#endif
+
+/* Get the address of a particular section or program header entry,
+ * accounting for the size of the entries. */
+
+#define OLD_SECTION_H(n) \
+ (*(ElfW(Shdr) *) ((byte *) old_section_h + old_file_h->e_shentsize * (n)))
+#define NEW_SECTION_H(n) \
+ (*(ElfW(Shdr) *) ((byte *) new_section_h + new_file_h->e_shentsize * (n)))
+#define OLD_PROGRAM_H(n) \
+ (*(ElfW(Phdr) *) ((byte *) old_program_h + old_file_h->e_phentsize * (n)))
+#define NEW_PROGRAM_H(n) \
+ (*(ElfW(Phdr) *) ((byte *) new_program_h + new_file_h->e_phentsize * (n)))
+
+#define PATCH_INDEX(n) \
+ do { \
+ if ((int) (n) >= growme_index) \
+ (n)++; } while (0)
+
+typedef unsigned char byte;
+
+/* Round X up to a multiple of Y. */
+
+static ElfW(Addr)
+round_up (ElfW(Addr) x, ElfW(Addr) y)
+{
+ int rem = x % y;
+ if (rem == 0)
+ return x;
+ return x - rem + y;
+}
+
+/* Return the index of the section named NAME.
+ SECTION_NAMES, FILE_NAME and FILE_H give information
+ about the file we are looking in.
+
+ If we don't find the section NAME, that is a fatal error
+ if NOERROR is 0; we return -1 if NOERROR is nonzero. */
+
+static int
+find_section (char *name,
+ const char *section_names,
+ char *file_name,
+ ElfW(Ehdr) *old_file_h,
+ ElfW(Shdr) *old_section_h,
+ int noerror)
+{
+ int idx;
+
+ for (idx = 1; idx < old_file_h->e_shnum; idx++)
+ {
+#ifdef DEBUG
+ fprintf (stderr, "Looking for %s - found %s\n", name,
+ section_names + OLD_SECTION_H (idx).sh_name);
+#endif
+ if (!strcmp (section_names + OLD_SECTION_H (idx).sh_name,
+ name))
+ return idx;
+ }
+
+ /* If we're here, we found nothing or return did not work */
+ if ( ! noerror)
+ fatal ("Can't find %s in %s.\n", name, file_name);
+
+ return -1;
+}
+
+/* ****************************************************************
+ * unexec
+ *
+ * driving logic.
+ *
+ * In ELF, this works by replacing the old .bss section with a new
+ * .data section, and inserting an empty .bss immediately afterwards.
+ *
+ */
+void
+unexec (char *new_name,
+ char *old_name,
+ uintptr_t data_start,
+ uintptr_t bss_start,
+ uintptr_t entry_address)
+{
+ int old_file;
+
+ struct stat stat_buf;
+ caddr_t old_base, new_base;
+
+ ElfW(Ehdr) *old_file_h, * new_file_h;
+ ElfW(Phdr) *old_program_h, * new_program_h;
+ ElfW(Shdr) *old_section_h, * new_section_h;
+ ElfW(Shdr) * growme = NULL, * grown = NULL;
+ ElfW(Addr) old_bss_addr = 0, new_data2_addr = 0;
+
+ int growme_index = -1;
+ int n, nn;
+ const char *old_section_names;
+ int old_mdebug_index, old_data_index;
+ int new_bss_addr, new_data2_size, new_data2_offset, new_file, new_file_size;
+
+ /* Open the old file */
+ if ( (old_file = open (old_name, O_RDONLY)) < 0 )
+ fatal ("Can't open %s for reading: errno %d\n", old_name, errno);
+
+ if (fstat (old_file, &stat_buf) == -1)
+ fatal ("Can't fstat (%s): errno %d\n", old_name, errno);
+
+ /* map old file into the address space. */
+ old_base = (caddr_t) mmap ((caddr_t) 0, stat_buf.st_size,
+ PROT_READ, MAP_SHARED, old_file, 0);
+ if (old_base == (caddr_t) MAP_FAILED)
+ fatal ("Can't mmap (%s): errno %d\n", old_name, errno);
+
+ old_file_h = (ElfW(Ehdr) *) old_base;
+ old_program_h = (ElfW(Phdr) *) ((byte *) old_base + old_file_h->e_phoff);
+ old_section_h = (ElfW(Shdr) *) ((byte *) old_base + old_file_h->e_shoff);
+ old_section_names = (const char *) old_base
+ + OLD_SECTION_H (old_file_h->e_shstrndx).sh_offset;
+
+ /* Find a section which we will grow by looking for the SHT_NOBITS
+ * section with ALLOCATE flag and with the biggest address. */
+ for (n = 1; n < old_file_h->e_shnum; n++) {
+ ElfW(Shdr) * sh = & OLD_SECTION_H(n);
+
+ if ((sh->sh_type == SHT_NOBITS) && (sh->sh_flags & SHF_ALLOC)) {
+ if ( old_bss_addr < sh->sh_addr ) {
+ growme = sh;
+ growme_index = n;
+ new_data2_addr = old_bss_addr = sh->sh_addr;
+ }
+ }
+ }
+
+ if (growme == NULL )
+ fatal ("Can't find a section to grow\n", 0, 0);
+
+ old_data_index = find_section (".data", old_section_names,
+ old_name, old_file_h, old_section_h, 0);
+
+ new_bss_addr = (ElfW(Addr)) sbrk (0);
+ new_data2_size = new_bss_addr - old_bss_addr;
+ new_data2_offset = OLD_SECTION_H (old_data_index).sh_offset +
+ (new_data2_addr - OLD_SECTION_H (old_data_index).sh_addr);
+
+ if ( new_bss_addr < old_bss_addr + growme->sh_size )
+ fatal (".bss shrank when undumping???\n", 0, 0);
+
+ /* Set the output file to the right size and mmap it. */
+ if ( (new_file = open (new_name, O_RDWR | O_CREAT, 0666)) < 0 )
+ fatal ("Can't create (%s): errno %d\n", new_name, errno);
+
+ new_file_size = stat_buf.st_size + old_file_h->e_shentsize + new_data2_size;
+
+ if (ftruncate (new_file, new_file_size))
+ fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno);
+
+ new_base = (caddr_t) mmap ((caddr_t) 0, new_file_size,
+ PROT_READ | PROT_WRITE,
+#ifdef UNEXEC_USE_MAP_PRIVATE
+ MAP_PRIVATE,
+#else
+ MAP_SHARED,
+#endif
+ new_file, 0);
+
+ if (new_base == (caddr_t) -1)
+ fatal ("Can't mmap (%s): errno %d\n", new_name, errno);
+
+ new_file_h = (ElfW(Ehdr) *) new_base;
+ new_program_h = (ElfW(Phdr) *) ((byte *) new_base + old_file_h->e_phoff);
+ new_section_h = (ElfW(Shdr) *) ((byte *) new_base + old_file_h->e_shoff +
+ new_data2_size);
+
+ /* Make our new file, program and section headers as copies of the
+ * originals. */
+ memcpy (new_file_h, old_file_h, old_file_h->e_ehsize);
+ memcpy (new_program_h, old_program_h,
+ old_file_h->e_phnum * old_file_h->e_phentsize);
+
+ /* Modify the e_shstrndx if necessary. */
+ PATCH_INDEX (new_file_h->e_shstrndx);
+
+ /* Fix up file header. We'll add one section. Section header is
+ * further away now. */
+ new_file_h->e_shoff += new_data2_size;
+ new_file_h->e_shnum += 1;
+
+ /* Fix up a new program header by extending the writable data
+ * segment so that the bss area is covered too. Find that segment by
+ * looking for one that starts before and ends after the .bss and is
+ * PT_LOADable. */
+ for (n = new_file_h->e_phnum - 1; n >= 0; n--) {
+ ElfW(Phdr) * ph = & NEW_PROGRAM_H(n);
+#ifdef DEBUG
+ printf ("%d @ %0x + %0x against %0x + %0x",
+ n, ph->p_vaddr, ph->p_memsz,growme->sh_addr, growme->sh_size);
+#endif
+ if ((ph->p_type == PT_LOAD) &&
+ (ph->p_vaddr <= growme->sh_addr) &&
+ ((ph->p_vaddr+ph->p_memsz) >= (growme->sh_addr + growme->sh_size))) {
+ /* Make sure that the size includes any padding before the
+ * old .bss section. */
+ ph->p_memsz = ph->p_filesz = new_bss_addr - ph->p_vaddr;
+#ifdef DEBUG
+ puts (" That's the one!");
+#endif
+ break;
+ }
+#ifdef DEBUG
+ putchar ('\n');
+#endif
+ }
+
+ if (n < 0)
+ fatal ("Couldn't find segment which covers %s",
+ old_section_names + growme->sh_name);
+
+ /* Walk through all section headers, insert the new data2 section
+ * right before the new bss section. */
+ for (n = 1, nn = 1; n < (int) old_file_h->e_shnum; n++, nn++) {
+ ElfW(Shdr) * nsec = & NEW_SECTION_H(nn);
+ ElfW(Shdr) * osec = & OLD_SECTION_H(n);
+
+ /* If this is the section we want to grow, insert the new data
+ * section before it. */
+ if ( osec == growme ) {
+ /* Steal the data section header for this data2 section but
+ * use the * 'grow' section's alignment. This * will assure
+ * that the new section * always be placed in the same spot
+ * * as the old section by any other * application. */
+ ElfW(Shdr) * od = &OLD_SECTION_H(old_data_index);
+
+ memcpy (nsec, od, new_file_h->e_shentsize);
+
+ nsec->sh_addr = new_data2_addr;
+ nsec->sh_offset = new_data2_offset;
+ nsec->sh_size = new_data2_size;
+ nsec->sh_addralign = osec->sh_addralign;
+
+ /* Copy over what we have in memory now. */
+ memcpy (nsec->sh_offset + new_base, (caddr_t) osec->sh_addr,
+ new_data2_size);
+ nn++;
+ grown = nsec++;
+ }
+
+ memcpy (nsec, osec, old_file_h->e_shentsize);
+
+ if ( osec == growme ) {
+ /* The new bss section's size is zero, and its file offset
+ * and virtual address should be off by NEW_DATA2_SIZE. */
+ nsec->sh_offset = grown->sh_offset + new_data2_size;
+ nsec->sh_addr = grown->sh_addr + new_data2_size;
+
+ /* Let the new bss section address alignment be the same as
+ * the section address alignment followed the old bss
+ * section, so this section will be placed in exactly the
+ * same place. */
+ nsec->sh_addralign = osec->sh_addralign;
+ nsec->sh_size = 0;
+ } else {
+ /* Any section that was originally placed AFTER the bss
+ * section should now be off by NEW_DATA2_SIZE. */
+ if ( round_up (nsec->sh_offset, growme->sh_addralign) >=
+ new_data2_offset)
+ nsec->sh_offset += new_data2_size;
+ }
+
+ /* Any section that was originally placed after the section *
+ * header table should now be off by the size of one section
+ * header table entry. */
+ if (nsec->sh_offset > new_file_h->e_shoff)
+ nsec->sh_offset += new_file_h->e_shentsize;
+
+
+ /* If any section hdr refers to the section after the new .data
+ * section, make it refer to next one because we have inserted a
+ * new section in between. */
+ PATCH_INDEX (nsec->sh_link);
+
+ /* For symbol tables, info is a symbol table index, so don't
+ * change it. */
+ if (nsec->sh_type != SHT_SYMTAB && nsec->sh_type != SHT_DYNSYM)
+ PATCH_INDEX (nsec->sh_info);
+
+ /* Any section which used to be NOBITS will now becomes PROGBITS
+ * if it's ALLOC-atable, unless, of cause, it's not the one we
+ * decided to grow */
+ if ( (osec->sh_type == SHT_NOBITS) && (osec->sh_flags & SHF_ALLOC) &&
+ (osec != growme ) ) {
+ nsec->sh_type = SHT_PROGBITS;
+ }
+
+ /* Now, start to copy the content of sections */
+ if ( nsec->sh_type != SHT_NULL || nsec->sh_type != SHT_NOBITS ) {
+
+ /* Write out the sections. .data and .data1 (and data2,
+ * called ".data" in the strings table) get copied from the
+ * current process instead of the old file. */
+ caddr_t src = old_base + osec->sh_offset;
+ const char * secname = old_section_names + nsec->sh_name;
+ const char * names[] = {
+ ".data",".sdata", ".lit4", ".lit8", ".sdata1", ".data1",
+ ".sbss", NULL};
+ int i;
+
+ for ( i=0; names[i] != NULL; i++ ) {
+ if ( ! strcmp (secname, names[i]) ) {
+ src = (caddr_t) osec->sh_addr;
+ break;
+ }
+ }
+
+ memcpy (nsec->sh_offset + new_base, src, nsec->sh_size);
+ }
+
+ old_mdebug_index = find_section (".mdebug", old_section_names,
+ old_name, old_file_h, old_section_h, 1);
+
+#if defined (__sony_news) && defined (_SYSTYPE_SYSV)
+ if (nsec->sh_type == SHT_MIPS_DEBUG && old_mdebug_index != -1) {
+ int diff = nsec->sh_offset-OLD_SECTION_H(old_mdebug_index).sh_offset;
+ HDRR *phdr = (HDRR *)(nsec->sh_offset + new_base);
+
+ if (diff) {
+ phdr->cbLineOffset += diff;
+ phdr->cbDnOffset += diff;
+ phdr->cbPdOffset += diff;
+ phdr->cbSymOffset += diff;
+ phdr->cbOptOffset += diff;
+ phdr->cbAuxOffset += diff;
+ phdr->cbSsOffset += diff;
+ phdr->cbSsExtOffset += diff;
+ phdr->cbFdOffset += diff;
+ phdr->cbRfdOffset += diff;
+ phdr->cbExtOffset += diff;
+ }
+ }
+#endif /* __sony_news && _SYSTYPE_SYSV */
+
+#if __sgi
+ /* Adjust the HDRR offsets in .mdebug and copy the line data if
+ * it's in its usual 'hole' in the object. Makes the new file
+ * debuggable with dbx. patches up two problems: the absolute
+ * file offsets in the HDRR record of .mdebug (see
+ * /usr/include/syms.h), and the ld bug that gets the line table
+ * in a hole in the elf file rather than in the .mdebug section
+ * proper.
+ *
+ * David Anderson. davea@sgi.com Jan 16,1994 */
+#define MDEBUGADJUST(__ct,__fileaddr) \
+ if (n_phdrr->__ct > 0) \
+ { \
+ n_phdrr->__fileaddr += movement; \
+ }
+
+ if (n == old_mdebug_index) {
+ HDRR * o_phdrr = (HDRR *)((byte *)old_base + osec->sh_offset);
+ HDRR * n_phdrr = (HDRR *)((byte *)new_base + nsec->sh_offset);
+ unsigned movement = new_data2_size;
+
+ MDEBUGADJUST (idnMax, cbDnOffset);
+ MDEBUGADJUST (ipdMax, cbPdOffset);
+ MDEBUGADJUST (isymMax, cbSymOffset);
+ MDEBUGADJUST (ioptMax, cbOptOffset);
+ MDEBUGADJUST (iauxMax, cbAuxOffset);
+ MDEBUGADJUST (issMax, cbSsOffset);
+ MDEBUGADJUST (issExtMax, cbSsExtOffset);
+ MDEBUGADJUST (ifdMax, cbFdOffset);
+ MDEBUGADJUST (crfd, cbRfdOffset);
+ MDEBUGADJUST (iextMax, cbExtOffset);
+
+ /* The Line Section, being possible off in a hole of the
+ * object, requires special handling. */
+ if (n_phdrr->cbLine > 0) {
+ if (o_phdrr->cbLineOffset >
+ osec->sh_offset+ osec->sh_size){
+ /* line data is in a hole in elf. do special copy
+ * and adjust for this ld mistake. */
+ n_phdrr->cbLineOffset += movement;
+
+ memcpy (n_phdrr->cbLineOffset + new_base,
+ o_phdrr->cbLineOffset + old_base, n_phdrr->cbLine);
+ } else {
+ /* somehow line data is in .mdebug as it is supposed
+ * to be. */
+ MDEBUGADJUST (cbLine, cbLineOffset);
+ }
+ }
+ }
+#endif /* __sgi */
+ /* If it is the symbol table, its st_shndx field needs to be
+ * patched. */
+ if (nsec->sh_type == SHT_SYMTAB || nsec->sh_type == SHT_DYNSYM) {
+ unsigned int num = nsec->sh_size / nsec->sh_entsize;
+ ElfW(Sym) * sym = (ElfW(Sym) *)(nsec->sh_offset + new_base);
+ byte *symnames = ((byte *) new_base +
+ NEW_SECTION_H (nsec->sh_link).sh_offset);
+
+ for (; num--; sym++) {
+ const char * symnam = (char *) (symnames + sym->st_name);
+
+ /* Update the symbol values of _edata and _end. */
+ if (strcmp (symnam, "_end") == 0
+ || strcmp (symnam, "end") == 0
+ || strcmp (symnam, "_edata") == 0
+ || strcmp (symnam, "edata") == 0)
+ memcpy (&sym->st_value, &new_bss_addr,sizeof (new_bss_addr));
+
+
+ if ((sym->st_shndx == SHN_UNDEF) || (sym->st_shndx == SHN_ABS)
+ || (sym->st_shndx == SHN_COMMON)
+ || (sym->st_shndx >= SHN_LOPROC &&
+ sym->st_shndx <= SHN_HIPROC))
+ continue;
+
+ PATCH_INDEX (sym->st_shndx);
+ }
+ }
+ }
+
+ /* This loop seeks out relocation sections for the data section, so
+ * that it can undo relocations performed by the runtime linker. */
+ for (n = new_file_h->e_shnum - 1; n; n--) {
+ ElfW(Shdr) section = NEW_SECTION_H (n);
+
+ if ( section.sh_type == SHT_REL || section.sh_type == SHT_RELA ) {
+ /* This code handles two different size structs, but there
+ * should be no harm in that provided that r_offset is
+ * always the first member. */
+ ElfW(Shdr) * info = & NEW_SECTION_H(section.sh_info);
+ const char * nm = old_section_names + info->sh_name;
+
+ if (!strcmp (nm, ".data") || !strcmp (nm, ".sdata")
+ || !strcmp (nm, ".lit4") || !strcmp (nm, ".lit8")
+ || !strcmp (nm, ".sdata1") || !strcmp (nm, ".data1")) {
+ ElfW(Addr) offset = info->sh_addr - info->sh_offset;
+ caddr_t end, reloc = old_base + section.sh_offset;
+
+ for (end = reloc + section.sh_size; reloc < end;
+ reloc += section.sh_entsize) {
+ ElfW(Addr) addr = ((ElfW(Rel) *) reloc)->r_offset - offset;
+#ifdef __alpha__
+ /* The Alpha ELF binutils currently have a bug that
+ * sometimes results in relocs that contain all
+ * zeroes. Work around this for now... */
+ if (((ElfW(Rel) *) reloc)->r_offset == 0)
+ continue;
+#endif
+ memcpy (new_base + addr, old_base + addr,
+ sizeof(ElfW(Addr)));
+ }
+ }
+ }
+ }
+
+#ifdef UNEXEC_USE_MAP_PRIVATE
+ if (lseek (new_file, 0, SEEK_SET) == -1)
+ fatal ("Can't rewind (%s): errno %d\n", new_name, errno);
+
+ if (write (new_file, new_base, new_file_size) != new_file_size)
+ fatal ("Can't write (%s): errno %d\n", new_name, errno);
+#endif
+
+ /* Close the files and make the new file executable. */
+ if (close (old_file))
+ fatal ("Can't close (%s): errno %d\n", old_name, errno);
+
+ if (close (new_file))
+ fatal ("Can't close (%s): errno %d\n", new_name, errno);
+
+ if (stat (new_name, &stat_buf) == -1)
+ fatal ("Can't stat (%s): errno %d\n", new_name, errno);
+
+ n = umask (777);
+ umask (n);
+ stat_buf.st_mode |= 0111 & ~n;
+ if (chmod (new_name, stat_buf.st_mode) == -1)
+ fatal ("Can't chmod (%s): errno %d\n", new_name, errno);
+}
projects / chise / xemacs-chise.git- / blobdiff