--- /dev/null
+/* Code to do an unexec for FreeBSD-1.1 for a temacs linked -Bdynamic.
+ Derived from unexnetbsd.c, which was derived from unexsunos4.c
+ Copyright (C) 1992, 1993 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.
+
+XEmacs 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 XEmacs; see the file COPYING. If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA. */
+
+/* Synched up with: Not in FSF? */
+
+/*
+Created 29-Oct-92 by Harlan Sexton
+Tweaked 06-Aug-93 by Dean Michaels to work with sun3.
+Converted 01-Dec-93 by Paul Mackerras to work with NetBSD shared libraries.
+Tweaked 26-Feb-94 by Shawn Carey for use with FreeBSD-1.1 shared libraries.
+*/
+
+/********************** Included .h Files **************************/
+
+#include <config.h>
+
+#include <stdarg.h>
+#include <sys/param.h>
+#include <sys/mman.h>
+#include <sys/file.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <string.h>
+#include <stdio.h>
+#include <a.out.h>
+#include <unistd.h>
+#include <ctype.h>
+#include <stab.h>
+#include <sys/dir.h>
+#include <link.h>
+
+/********************** Macros *************************************/
+
+#define SYS_ERR strerror(errno)
+
+#define MASK_UP(x,p_of_two) \
+ ((((unsigned long) (x)) + ((p_of_two) - 1)) & (~((p_of_two) - 1)))
+
+#define MASK_DOWN(x,p_of_two) (((unsigned long) (x)) & (~((p_of_two) - 1)))
+
+/********************** Typedefs and Structs ***********************/
+
+struct translation_struct
+{
+ long txtaddr;
+ long txtoff;
+ long dataddr;
+ long datoff;
+ long bssaddr;
+ long endaddr;
+};
+
+/********************** Function Prototypes/Declarations ***********/
+
+static void unexec_error (CONST char *m, int use_errno, ...);
+static int unexec_open (char *filename, int flag, int mode);
+static caddr_t unexec_mmap (int fd, size_t len, int prot, int flags);
+static long unexec_seek (int fd, long position);
+static void unexec_read (int fd, long position, char *buf, int bytes);
+static void unexec_write (int fd, long position, char *buf, int bytes);
+static void unexec_pad (int fd, int bytes);
+static void unexec_fstat (int fd, struct stat *statptr);
+static void unexec_fchmod (int fd, int mode);
+static long unexec_addr_to_offset (long addr, struct translation_struct *ts);
+static void copy_relocation_site (struct relocation_info *ri,
+ caddr_t from_base_addr,
+ caddr_t to_base_addr,
+ struct translation_struct *ts);
+static void reset_symtab (struct nlist *start, struct nlist *end,
+ char *strtab, long edata_value, long end_value,
+ int shlib_image);
+static void reset_ldso_symtab (struct nzlist *start, struct nzlist *end,
+ char *strtab, long edata_value, long end_value,
+ int shlib_image);
+int run_time_remap (char *dummy);
+
+/********************** Variables **********************************/
+
+/* for reporting error messages from system calls */
+extern int errno;
+extern int _DYNAMIC;
+extern char **environ;
+
+static unsigned long sbrk_of_0_at_unexec;
+
+/*******************************************************************/
+
+static void
+unexec_error (CONST char *fmt, int use_errno, ...)
+{
+ CONST char *err_msg = SYS_ERR;
+ va_list args;
+
+ fprintf (stderr, "unexec - ");
+ va_start (args, use_errno);
+ vfprintf (stderr, fmt, args);
+ va_end (args);
+
+ if (use_errno)
+ fprintf (stderr, ": %s", err_msg);
+ fprintf (stderr, "\n");
+ exit (1);
+ return;
+}
+
+static int
+unexec_open (char *filename, int flag, int mode)
+{
+ int fd;
+
+ errno = 0;
+
+ fd = open (filename, flag, mode);
+
+ if (fd < 0)
+ unexec_error ("Failure opening file %s", 1, filename);
+ return fd;
+}
+
+static caddr_t
+unexec_mmap (int fd, size_t len, int prot, int flags)
+{
+ caddr_t return_val;
+
+ unexec_seek (fd, 0);
+ errno = 0;
+ return_val = mmap (0, len, prot, flags, fd, 0);
+
+ if (return_val == (caddr_t) -1)
+ unexec_error ("Failure mmap'ing file", 1);
+ return return_val;
+}
+
+
+static long
+unexec_seek (int fd, long position)
+{
+ long seek_value;
+
+ if (fd <= 0)
+ unexec_error ("No file open in which to seek", 0);
+
+ errno = 0;
+
+ if (position < 0)
+ seek_value = (long) lseek (fd, 0, L_INCR);
+ else
+ seek_value = (long) lseek (fd, position, L_SET);
+
+ if (seek_value < 0)
+ unexec_error ("Failed to do a seek to 0x%x in %s", 1,
+ position, "unexec() output file");
+
+ return seek_value;
+}
+
+static void
+unexec_read (int fd, long position, char *buf, int bytes)
+{
+ int n_read;
+ int remains = bytes;
+ position = unexec_seek (fd, position);
+
+ if (bytes < 0)
+ unexec_error ("Attempted read of %d bytes", 0, bytes);
+
+ errno = 0;
+
+ while (remains > 0)
+ {
+ n_read = read (fd, buf, remains);
+ if (n_read <= 0)
+ unexec_error ("Read failed for 0x%x bytes at offset 0x%x in %s",
+ 1, bytes, position, "unexec() output file");
+ buf += n_read;
+ remains -= n_read;
+ }
+
+ return;
+}
+
+static void
+unexec_write (int fd, long position, char *buf, int bytes)
+{
+ int n_written;
+ int remains = bytes;
+ position = unexec_seek (fd, position);
+
+ if (bytes < 0)
+ unexec_error ("Attempted write of %d bytes in %s",
+ 0, bytes, "unexec() output file");
+
+ errno = 0;
+
+ while (remains > 0)
+ {
+ n_written = write (fd, buf, remains);
+ if (n_written <= 0)
+ unexec_error ("Write failed for 0x%x bytes at offset 0x%x in %s",
+ 1, bytes, position, "unexec() output file");
+ buf += n_written;
+ remains -= n_written;
+ }
+
+ return;
+}
+
+static void
+unexec_pad (int fd, int bytes)
+{
+ if (bytes > 0)
+ {
+ char buf[1024];
+ int remaining = bytes;
+
+ memset (buf, 0, sizeof (buf));
+
+ while (remaining > 0)
+ {
+ int this_write = (remaining > sizeof(buf))?sizeof(buf):remaining;
+ unexec_write (fd, -1, buf, this_write);
+ remaining -= this_write;
+ }
+ }
+}
+
+static void
+unexec_fstat (int fd, struct stat *statptr)
+{
+ errno = 0;
+ if (-1 == fstat (fd, statptr))
+ unexec_error ("fstat() failed for descriptor %d", 1, fd);
+ return;
+}
+
+static void
+unexec_fchmod (int fd, int mode)
+{
+ errno = 0;
+ if (-1 == fchmod (fd, mode))
+ unexec_error ("fchmod() failed for descriptor %d", 1, fd);
+ return;
+}
+
+static long
+unexec_addr_to_offset (long addr, struct translation_struct *ts)
+
+{
+ if ((addr < ts->txtaddr) || (addr >= ts->bssaddr))
+ return -1;
+ else if (addr >= ts->dataddr)
+ return ((long) ((addr - ts->dataddr) + ts->datoff));
+ else
+ return ((long) ((addr - ts->txtaddr) + ts->txtoff));
+}
+
+
+/*
+ * "LD.SO" DATA AND SYMBOL TABLE OPERATIONS
+ */
+
+static void
+copy_relocation_site (struct relocation_info *ri,
+ caddr_t from_base_addr,
+ caddr_t to_base_addr,
+ struct translation_struct *ts)
+{
+ long offset;
+ caddr_t from, to;
+
+ /* We can get relocation sites in the bss region, for objects whose
+ contents are copied from a shared library. We don't need or want
+ to restore these at present. */
+#ifndef sparc
+ if (ri->r_copy)
+ return;
+#else
+ /* Struct relocation_info_sparc doesn't have member r_copy.
+ Instead, we use the address to check if this is run-time-copied. */
+ if (ri->r_address >= ts->bssaddr && ri->r_address < ts->endaddr)
+ return;
+#endif
+
+ offset = unexec_addr_to_offset (ri->r_address, ts);
+ if (offset == -1)
+ unexec_error ("bad relocation address 0x%x (0x%x)", 0, ri->r_address,
+ ((long *)ri)[1]);
+
+ from = from_base_addr + offset;
+ to = to_base_addr + offset;
+ /* This stuff should be in a md_ file somewhere... */
+#ifndef sparc
+ switch (ri->r_length)
+ {
+ case 0:
+ *((char *) to) = *((char *) from);
+ break;
+ case 1:
+ *((short *) to) = *((short *) from);
+ break;
+ case 2:
+ *((long *) to) = *((long *) from);
+ break;
+ default:
+ unexec_error ("unknown reloc length %d seen during unexec()",
+ 0, ri->r_length);
+ break;
+ }
+#else /* sparc */
+ switch (ri->r_type)
+ {
+ case RELOC_8:
+ case RELOC_DISP8:
+ *((char *) to) = *((char *) from);
+ break;
+ case RELOC_16:
+ case RELOC_DISP16:
+ *((short *) to) = *((short *) from);
+ break;
+ case RELOC_LO10:
+ case RELOC_13:
+ case RELOC_22:
+ case RELOC_HI22:
+ case RELOC_WDISP22:
+ case RELOC_WDISP30:
+ case RELOC_32:
+ case RELOC_DISP32:
+ case RELOC_GLOB_DAT:
+ *((long *) to) = *((long *) from);
+ break;
+ case RELOC_JMP_SLOT:
+ {
+ long *target = (long *) to;
+ long *source = (long *) from;
+ *target = *source;
+ target++;
+ source++;
+ *target = *source;
+ target++;
+ source++;
+ *target = *source;
+ }
+ break;
+ default:
+ unexec_error ("unknown reloc type %d seen during unexec()",
+ 0, ri->r_type);
+ break;
+ }
+#endif /* sparc */
+}
+
+static void
+reset_symtab (struct nlist *start, struct nlist *end, char *strtab,
+ long edata_value, long end_value, int shlib_image)
+{
+ struct nlist *tmp = start;
+ int found_edata = 0;
+ int found_end = 0;
+
+ while (tmp < end)
+ {
+ int type = tmp->n_type;
+
+ if ((type == (N_UNDF | N_EXT)) &&
+ (tmp->n_value != 0))
+ unexec_error ("unexec'ing image has COMMON symbols in it -- we quit!",
+ 0);
+
+ if (!(type & N_STAB))
+ {
+ if (!found_edata &&
+ (type == (N_EXT | N_DATA)) &&
+ tmp->n_un.n_strx &&
+ !strcmp ("_edata", strtab + tmp->n_un.n_strx))
+ {
+ tmp->n_value = edata_value;
+ found_edata = 1;
+ }
+
+
+ if ((type & N_TYPE) == N_BSS)
+ {
+ if (!found_end &&
+ (type == (N_EXT | N_BSS)) &&
+ tmp->n_un.n_strx &&
+ !strcmp ("_end", strtab + tmp->n_un.n_strx))
+ {
+ tmp->n_value = end_value;
+ found_end = 1;
+ }
+ else if (type & N_EXT)
+ tmp->n_type = N_DATA | N_EXT;
+ else
+ tmp->n_type = N_DATA;
+ }
+
+ /* the way things are being handled here, having sbrk() in the
+ image is fatal for an image linked with shared lib's (although
+ the code could be modified to support it), but this should
+ never happen anyway */
+ if (shlib_image &&
+ (type == (N_EXT | N_TEXT)) &&
+ tmp->n_un.n_strx &&
+ !strcmp ("_sbrk", strtab + tmp->n_un.n_strx))
+ unexec_error ("unexec'd shlib image has sbrk() in it -- we quit!",
+ 0);
+ }
+
+ tmp++;
+ }
+}
+
+static void
+reset_ldso_symtab (struct nzlist *start, struct nzlist *end, char *strtab,
+ long edata_value, long end_value, int shlib_image)
+{
+ struct nzlist *tmp = start;
+ int found_edata = 0;
+ int found_end = 0;
+
+ while (tmp < end) {
+ int type = tmp->nz_type;
+/*
+ * the following code breaks under FreeBSD-1.1-BETA, but everything
+ * seems to work perfectly if it's commented out. This did not break
+ * anything until the changes to ld.so were made.
+ */
+/*
+ if ((type == (N_UNDF | N_EXT)) && (tmp->nz_value != 0))
+ unexec_error("unexec'ing image has COMMON symbols in rel -- we quit!",0);
+*/
+ if (!(type & N_STAB)) {
+ if (!found_edata &&
+ (type == (N_EXT | N_DATA)) &&
+ !strcmp ("_edata", strtab + tmp->nz_strx)) {
+ tmp->nz_value = edata_value;
+ found_edata = 1;
+ }
+
+ if ((type & N_TYPE) == N_BSS) {
+ if (!found_end &&
+ (type == (N_EXT | N_BSS)) &&
+ !strcmp ("_end", strtab + tmp->nz_strx)) {
+ tmp->nz_value = end_value;
+ found_end = 1;
+ } else if (type & N_EXT)
+ tmp->nz_type = N_DATA | N_EXT;
+ else
+ tmp->nz_type = N_DATA;
+ }
+
+ /* the way things are being handled here, having sbrk() in the
+ image is fatal for an image linked with shared lib's (although
+ the code could be modified to support it), but this should
+ never happen anyway */
+ if (shlib_image &&
+ (type == (N_EXT | N_TEXT)) &&
+ !strcmp ("_sbrk", strtab + tmp->nz_strx))
+ unexec_error("unexec'd shlib image has sbrk() ref -- we quit!", 0);
+ }
+ tmp++;
+ }
+}
+
+extern int getpagesize (void);
+
+/*
+ * EXPORTED FUNCTIONS
+ */
+
+/* this has to be a global variable to prevent the optimizers from
+ * assuming that it can not be 0.
+*/
+static void *dynamic_addr = (void *) &_DYNAMIC;
+
+int
+unexec (char *new_name, char *old_name,
+ unsigned int emacs_edata, unsigned int dummy1, unsigned int dummy2)
+{
+ /* ld.so data */
+ struct _dynamic *ld = 0;
+ struct section_dispatch_table *ld2 = 0;
+ /* old and new state */
+ int old_fd;
+ int new_fd;
+ caddr_t old_base_addr;
+ caddr_t new_base_addr;
+ struct exec old_hdr;
+ struct exec new_hdr;
+ struct stat old_buf;
+ struct stat new_buf;
+ /* some process specific "constants" */
+ unsigned long n_pagsiz, new_edata;
+ long page_size = getpagesize ();
+ caddr_t plt_end;
+ caddr_t current_break = (caddr_t) sbrk (0);
+
+ if (!page_size)
+ unexec_error ("unexec() failed because we can't get the size of a page!",
+ 0);
+
+ /* see if this is a -Bdynamic image -- if so, find ld.so structures */
+ if (dynamic_addr)
+ {
+ ld = (struct _dynamic *) dynamic_addr;
+ ld2 = ld->d_un.d_sdt;
+ if (ld->d_version < LD_VERSION_BSD)
+ unexec_error ("%s linked with obsolete version of ld -- we quit!",
+ 0, old_name);
+ }
+
+ /* open the old and new files, figuring out how big the old one is
+ so that we can map it in */
+ old_fd = unexec_open (old_name, O_RDONLY, 0);
+ new_fd = unexec_open (new_name, O_RDWR | O_CREAT | O_TRUNC, 0666);
+
+ /* setup the header and the statbuf for old_fd */
+ unexec_read (old_fd, 0, (char *) &old_hdr, sizeof (old_hdr));
+ unexec_fstat (old_fd, &old_buf);
+
+
+ /* set up some important constants */
+ n_pagsiz = __LDPGSZ;
+ if (dynamic_addr)
+ plt_end = (caddr_t) MASK_UP (ld2->sdt_plt + ld2->sdt_plt_sz, sizeof (double));
+ else
+ plt_end = (caddr_t) N_DATADDR (old_hdr);
+
+#if 0
+ /* never write protect the variable "environ", defined in /lib/crt0.o, and
+ set in process.c and callproc.c */
+ mprotect_bottom_addr = ((unsigned long) &environ) + sizeof (char **);
+ /* never protect ABOVE the end of data emacs_edata specified */
+ mprotect_top_addr = MIN (emacs_edata, N_DATADDR (old_hdr) + old_hdr.a_data);
+#endif
+
+ /* Set up the image of the old file */
+ old_base_addr = unexec_mmap (old_fd, old_buf.st_size, PROT_READ,
+ MAP_FILE | MAP_PRIVATE);
+ close (old_fd);
+
+ /* set up the new exec */
+ new_hdr = old_hdr;
+ new_edata = (unsigned long) MASK_UP (current_break, n_pagsiz);
+ new_hdr.a_data = new_edata - ((unsigned long) N_DATADDR (old_hdr));
+ new_hdr.a_bss = 0;
+
+ /* set up this variable, in case we want to reset "the break"
+ when restarting */
+ sbrk_of_0_at_unexec = ((unsigned long) MASK_UP (current_break, n_pagsiz));
+
+ /* Write out the first approximation to the new file. The sizes of
+ each section will be correct, but there will be a number of
+ corrections that will need to be made. */
+ {
+ long old_datoff = N_DATOFF (old_hdr);
+ long old_dataddr = N_DATADDR (old_hdr);
+ long new_treloff = N_RELOFF (new_hdr);
+ long old_treloff = N_RELOFF (old_hdr);
+ long ld_so_size = ((unsigned long) plt_end) - old_dataddr;
+ long real_data_size = current_break - plt_end;
+ long pad_size =
+ MASK_UP (current_break, n_pagsiz) - ((unsigned long) current_break);
+
+
+ /* First, write the text segment with new header -- copy everything until
+ the start of the data segment from the old file, and then go back and
+ write the new header. */
+ unexec_write (new_fd, 0, old_base_addr, old_datoff + ld_so_size);
+ unexec_write (new_fd, 0, (char *) &new_hdr, sizeof (new_hdr));
+
+ /* Copy the rest of the data segment from the running image. */
+ unexec_write (new_fd, old_datoff + ld_so_size,
+ plt_end, real_data_size);
+
+ /* pad out the data segment */
+ unexec_pad (new_fd, pad_size);
+
+ /* Finally, copy the symbol table information from the old file. */
+ unexec_write (new_fd, new_treloff,
+ old_base_addr + old_treloff,
+ old_buf.st_size - old_treloff);
+ }
+
+
+ /* Next, map in the output file so that we can jump around fixing it
+ up. We retain the old file so that we can refer to it. */
+ unexec_fstat (new_fd, &new_buf);
+ new_base_addr = unexec_mmap (new_fd,
+ MASK_UP (new_buf.st_size, page_size),
+ PROT_READ | PROT_WRITE,
+ MAP_FILE | MAP_SHARED);
+
+
+
+ /* We need to do 2 things. First, make sure that _edata and _end (and
+ hence, curbrk) are set to the correct values. At the same time, for
+ neatness and to help with debugging, mark all the types of all ld.so
+ and nm BSS symbols in the new file to be DATA, and make sure that
+ there are no COMMON symbols in the output file, as any references to
+ these can lose really big. Second, reset all of the ld.so "relocation
+ sites" in the new file to have the values that appear in the old file
+ -- the failure to do this was the biggest loser in the old version of
+ this code. */
+
+ /* STEP 1 */
+ /* Reset the regular symbol table first. */
+ reset_symtab ((struct nlist *) (new_base_addr + N_SYMOFF(new_hdr)),
+ (struct nlist *) (new_base_addr + N_SYMOFF(new_hdr) +
+ new_hdr.a_syms),
+ (char *) (new_base_addr + N_STROFF(new_hdr)),
+ new_edata, new_edata,
+ !!dynamic_addr);
+
+ /* Now reset the ld.so symbol table. */
+ if (dynamic_addr)
+ {
+ struct translation_struct ts;
+ struct relocation_info *tmp, *end;
+ caddr_t syms, strings;
+
+ /* set up the structure that we use to translate addresses in the
+ old file into file offsets */
+ ts.txtaddr = N_TXTADDR (old_hdr);
+ ts.txtoff = N_TXTOFF (old_hdr);
+ ts.dataddr = N_DATADDR (old_hdr);
+ ts.datoff = N_DATOFF (old_hdr);
+ ts.bssaddr = N_DATADDR (old_hdr) + old_hdr.a_data;
+ ts.endaddr = ts.bssaddr + old_hdr.a_bss;
+
+ syms = new_base_addr + unexec_addr_to_offset(ld2->sdt_nzlist, &ts);
+ strings = new_base_addr + unexec_addr_to_offset(ld2->sdt_strings, &ts);
+ reset_ldso_symtab ((struct nzlist *) syms, (struct nzlist *) strings,
+ (char *) strings,
+ new_edata, new_edata,
+ !!dynamic_addr);
+
+ /* STEP 2 */
+ tmp = (struct relocation_info *)
+ (old_base_addr + unexec_addr_to_offset(ld2->sdt_rel, &ts));
+ end = (struct relocation_info *)
+ (old_base_addr + unexec_addr_to_offset(ld2->sdt_hash, &ts));
+ while (tmp < end)
+ {
+ copy_relocation_site (tmp, old_base_addr, new_base_addr, &ts);
+ tmp++;
+ }
+ }
+
+ /* get rid of the mmap-ed file space and make the output file
+ executable -- then quit */
+ munmap (new_base_addr, MASK_UP (new_buf.st_size, page_size));
+ munmap (old_base_addr, MASK_UP (old_buf.st_size, page_size));
+ unexec_fchmod (new_fd, 0755);
+ close (new_fd);
+ return 0;
+}
+
+
+int
+run_time_remap (char *dummy)
+{
+ unsigned long current_sbrk = (unsigned long) sbrk (0);
+
+#if __FreeBSD_version < 300000 /* 2.x can work with this code */
+ if (sbrk_of_0_at_unexec < current_sbrk)
+ {
+ if (sbrk_of_0_at_unexec != 0)
+ fprintf (stderr, "Absurd new brk addr = %lx (current = %lx)\n",
+ sbrk_of_0_at_unexec, current_sbrk);
+ }
+ else
+#endif
+ if (sbrk_of_0_at_unexec > current_sbrk)
+ {
+ errno = 0;
+ if (brk ((caddr_t) sbrk_of_0_at_unexec))
+ fprintf (stderr, "failed to change brk addr to %lx: %s\n",
+ sbrk_of_0_at_unexec, SYS_ERR);
+ }
+
+#if 0
+/* with proper COW, i don't think we really need to do this... */
+ {
+ long page_size = getpagesize();
+ unsigned long base_addr = MASK_UP (mprotect_bottom_addr, page_size);
+ unsigned long top_addr = MASK_DOWN (mprotect_top_addr, page_size);
+ long len = top_addr - base_addr;
+
+ if (len > 0)
+ {
+ errno = 0;
+ if (mprotect ((caddr_t) base_addr, len, PROT_READ | PROT_EXEC))
+ fprintf (stderr, "failed to change protection on data pages: %s\n",
+ SYS_ERR);
+ }
+ }
+#endif
+
+ return 0;
+}
projects / chise / xemacs-chise.git.1 / blobdiff