+++ /dev/null
-/* Unexec for Sunos 4 using shared libraries.
- Copyright (C) 1990, 1994, 1999, 2001, 2002, 2003, 2004,
- 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
-
-This file is part of GNU Emacs.
-
-GNU Emacs 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 3, 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., 51 Franklin Street, Fifth Floor,
-Boston, MA 02110-1301, USA. */
-
-/* Contributed by Viktor Dukhovni. */
-/*
- * Unexec for Berkeley a.out format + SUNOS shared libraries
- * The unexeced executable contains the __DYNAMIC area from the
- * original text file, and then the rest of data + bss + malloced area of
- * the current process. (The __DYNAMIC area is at the top of the process
- * data segment, we use "data_start" defined externally to mark the start
- * of the "real" data segment.)
- *
- * For programs that want to remap some of the data segment read only
- * a run_time_remap is provided. This attempts to remap largest area starting
- * and ending on page boundaries between "data_start" and "bndry"
- * For this it to figure out where the text file is located. A path search
- * is attempted after trying argv[0] and if all fails we simply do not remap
- *
- * One feature of run_time_remap () is mandatory: reseting the break.
- *
- * Note that we can no longer map data into the text segment, as this causes
- * the __DYNAMIC struct to become read only, breaking the runtime loader.
- * Thus we no longer need to mess with a private crt0.c, the standard one
- * will do just fine, since environ can live in the writable area between
- * __DYNAMIC and data_start, just make sure that pre-crt0.o (the name
- * is somewhat abused here) is loaded first!
- *
- */
-
-#ifdef emacs
-#include <config.h>
-#endif
-
-#include <sys/param.h>
-#include <sys/mman.h>
-#include <sys/file.h>
-#include <sys/stat.h>
-#include <string.h>
-#include <stdio.h>
-#include <a.out.h>
-
-#if defined (SUNOS4) || defined (__FreeBSD__) || defined (__NetBSD__)
-#define UNDO_RELOCATION
-#endif
-
-#ifdef UNDO_RELOCATION
-#include <link.h>
-#endif
-
-#ifdef HAVE_UNISTD_H
-#include <unistd.h>
-#endif
-
-/* NetBSD needs this bit, but SunOS does not have it. */
-#ifndef MAP_FILE
-#define MAP_FILE 0
-#endif
-
-
-/*
- * for programs other than emacs
- * define data_start + initialized here, and make sure
- * this object is loaded first!
- * emacs will define these elsewhere, and load the object containing
- * data_start (pre-crt0.o or firstfile.o?) first!
- * The custom crt0.o *must not* be loaded!
- */
-#ifndef emacs
- static int data_start = 0;
- static int initialized = 0;
-#else
- extern int initialized;
- extern unsigned data_start;
- extern int pureptr;
-#endif
-
-extern char *getenv ();
-static unsigned brk_value;
-static struct exec nhdr;
-static int rd_only_len;
-static long cookie;
-
-
-unexec (new_name, a_name, bndry, bss_start, entry)
- char *new_name, *a_name;
- unsigned bndry, bss_start, entry;
-{
- int fd, new;
- char *old;
- struct exec ohdr; /* Allocate on the stack, not needed in the next life */
- struct stat stat;
-
- if ((fd = open (a_name, O_RDONLY)) < 0)
- {
- fprintf (stderr, "%s: open: ", a_name);
- perror (a_name);
- exit (1);
- }
- if ((new = open (new_name, O_WRONLY | O_CREAT, 0666)) == -1)
- {
- fprintf (stderr, "%s: open: ", a_name);
- perror (new_name);
- exit (1);
- }
-
- if ((fstat (fd, &stat) == -1))
- {
- fprintf (stderr, "%s: ", a_name);
- perror ("fstat");
- exit (1);
- }
-
- old = (char *)mmap (0, stat.st_size, PROT_READ, MAP_FILE|MAP_SHARED, fd, 0);
- if (old == (char *)-1)
- {
- fprintf (stderr, "%s: ", a_name);
- perror ("mmap");
- exit (1);
- }
- close (fd);
-
- nhdr = ohdr = (*(struct exec *)old);
-
-
- /*
- * Remember a magic cookie so we know we've got the right binary
- * when remapping.
- */
- cookie = time (0);
-
- /* Save the break, it is reset to &_end (by ld.so?). */
- brk_value = (unsigned) sbrk (0);
-
- /*
- * Round up data start to a page boundary (Lose if not a 2 power!)
- */
- data_start = ((((int)&data_start) - 1) & ~(N_PAGSIZ (nhdr) - 1)) + N_PAGSIZ (nhdr);
-
- /*
- * Round down read only pages to a multiple of the page size
- */
- if (bndry)
- rd_only_len = ((int)bndry & ~(N_PAGSIZ (nhdr) - 1)) - data_start;
-
-#ifndef emacs
- /* Have to do this some time before dumping the data */
- initialized = 1;
-#endif
-
- /* Handle new data and bss sizes and optional new entry point.
- No one actually uses bss_start and entry, but tradition compels
- one to support them.
- Could complain if bss_start > brk_value,
- but the caller is *supposed* to know what she is doing. */
- nhdr.a_data = (bss_start ? bss_start : brk_value) - N_DATADDR (nhdr);
- nhdr.a_bss = bss_start ? brk_value - bss_start : 0;
- if (entry)
- nhdr.a_entry = entry;
-
- /*
- * Write out the text segment with new header
- * Dynamic executables are ZMAGIC with N_TXTOFF==0 and the header
- * part of the text segment, but no need to rely on this.
- * So write the TEXT first, then go back replace the header.
- * Doing it in the other order is less general!
- */
- lseek (new, N_TXTOFF (nhdr), L_SET);
- write (new, old + N_TXTOFF (ohdr), N_TXTOFF (ohdr) + ohdr.a_text);
- lseek (new, 0L, L_SET);
- write (new, &nhdr, sizeof (nhdr));
-
- /*
- * Write out the head of the old data segment from the file not
- * from core, this has the unresolved __DYNAMIC relocation data
- * we need to reload
- */
- lseek (new, N_DATOFF (nhdr), L_SET);
- write (new, old + N_DATOFF (ohdr), (int)&data_start - N_DATADDR (ohdr));
-
- /*
- * Copy the rest of the data from core
- */
- write (new, &data_start, N_BSSADDR (nhdr) - (int)&data_start);
-
- /*
- * Copy the symbol table and line numbers
- */
- lseek (new, N_TRELOFF (nhdr), L_SET);
- write (new, old + N_TRELOFF (ohdr), stat.st_size - N_TRELOFF (ohdr));
-
- /* Some other BSD systems use this file.
- We don't know whether this change is right for them. */
-#ifdef UNDO_RELOCATION
- /* Undo the relocations done at startup by ld.so.
- It will do these relocations again when we start the dumped Emacs.
- Doing them twice gives incorrect results. */
- {
- unsigned long daddr = N_DATADDR (ohdr);
- unsigned long rel, erel;
-#ifdef SUNOS4
-#ifdef SUNOS4_SHARED_LIBRARIES
- extern struct link_dynamic _DYNAMIC;
-
- /* SunOS4.x's ld_rel is relative to N_TXTADDR. */
- if (!ohdr.a_dynamic)
- /* This was statically linked. */
- rel = erel = 0;
- else if (_DYNAMIC.ld_version < 2)
- {
- rel = _DYNAMIC.ld_un.ld_1->ld_rel + N_TXTADDR (ohdr);
- erel = _DYNAMIC.ld_un.ld_1->ld_hash + N_TXTADDR (ohdr);
- }
- else
- {
- rel = _DYNAMIC.ld_un.ld_2->ld_rel + N_TXTADDR (ohdr);
- erel = _DYNAMIC.ld_un.ld_2->ld_hash + N_TXTADDR (ohdr);
- }
-#else /* not SUNOS4_SHARED_LIBRARIES */
- rel = erel = 0;
-#endif /* not SUNOS4_SHARED_LIBRARIES */
-#ifdef sparc
-#define REL_INFO_TYPE struct reloc_info_sparc
-#else
-#define REL_INFO_TYPE struct relocation_info
-#endif /* sparc */
-#define REL_TARGET_ADDRESS(r) (((REL_INFO_TYPE *)(r))->r_address)
-#endif /* SUNOS4 */
-#if defined (__FreeBSD__) || defined (__NetBSD__)
- extern struct _dynamic _DYNAMIC;
-
- /* FreeBSD's LD_REL is a virtual address itself. */
- rel = LD_REL (&_DYNAMIC);
- erel = rel + LD_RELSZ (&_DYNAMIC);
-#define REL_INFO_TYPE struct relocation_info
-#define REL_TARGET_ADDRESS(r) (((REL_INFO_TYPE *)(r))->r_address)
-#endif
-
- for (; rel < erel; rel += sizeof (REL_INFO_TYPE))
- {
- /* This is the virtual address where ld.so will do relocation. */
- unsigned long target = REL_TARGET_ADDRESS (rel);
- /* This is the offset in the data segment. */
- unsigned long segoffset = target - daddr;
-
- /* If it is located below data_start, we have to do nothing here,
- because the old data has been already written to the location. */
- if (target < (unsigned long)&data_start)
- continue;
-
- lseek (new, N_DATOFF (nhdr) + segoffset, L_SET);
- write (new, old + N_DATOFF (ohdr) + segoffset, sizeof (unsigned long));
- }
- }
-#endif /* UNDO_RELOCATION */
-
- fchmod (new, 0755);
-}
-
-void
-run_time_remap (progname)
- char *progname;
-{
- char aout[MAXPATHLEN];
- register char *path, *p;
-
- /* Just in case */
- if (!initialized)
- return;
-
- /* Restore the break */
- brk ((char *) brk_value);
-
- /* If nothing to remap: we are done! */
- if (rd_only_len == 0)
- return;
-
- /*
- * Attempt to find the executable
- * First try argv[0], will almost always succeed as shells tend to give
- * the full path from the hash list rather than using execvp ()
- */
- if (is_it (progname))
- return;
-
- /*
- * If argv[0] is a full path and does not exist, not much sense in
- * searching further
- */
- if (strchr (progname, '/'))
- return;
-
- /*
- * Try to search for argv[0] on the PATH
- */
- path = getenv ("PATH");
- if (path == NULL)
- return;
-
- while (*path)
- {
- /* copy through ':' or end */
- for (p = aout; *p = *path; ++p, ++path)
- if (*p == ':')
- {
- ++path; /* move past ':' */
- break;
- }
- *p++ = '/';
- strcpy (p, progname);
- /*
- * aout is a candidate full path name
- */
- if (is_it (aout))
- return;
- }
-}
-
-is_it (filename)
- char *filename;
-{
- int fd;
- long filenames_cookie;
- struct exec hdr;
-
- /*
- * Open an executable and check for a valid header!
- * Can't bcmp the header with what we had, it may have been stripped!
- * so we may save looking at non executables with the same name, mostly
- * directories.
- */
- fd = open (filename, O_RDONLY);
- if (fd != -1)
- {
- if (read (fd, &hdr, sizeof (hdr)) == sizeof (hdr)
- && !N_BADMAG (hdr) && N_DATOFF (hdr) == N_DATOFF (nhdr)
- && N_TRELOFF (hdr) == N_TRELOFF (nhdr))
- {
- /* compare cookies */
- lseek (fd, N_DATOFF (hdr) + (int)&cookie - N_DATADDR (hdr), L_SET);
- read (fd, &filenames_cookie, sizeof (filenames_cookie));
- if (filenames_cookie == cookie)
- { /* Eureka */
-
- /*
- * Do the mapping
- * The PROT_EXEC may not be needed, but it is safer this way.
- * should the shared library decide to indirect through
- * addresses in the data segment not part of __DYNAMIC
- */
- mmap ((char *) data_start, rd_only_len, PROT_READ | PROT_EXEC,
- MAP_FILE | MAP_SHARED | MAP_FIXED, fd,
- N_DATOFF (hdr) + data_start - N_DATADDR (hdr));
- close (fd);
- return 1;
- }
- }
- close (fd);
- }
- return 0;
-}
-
-/* arch-tag: 30227420-2c6f-4700-a4f8-9e45e52f53b1
- (do not change this comment) */
projects / emacs.git / commitdiff