freebsd-ports/editors/emacs/files/patch-ad

--- src/unexfreebsd.c.orig	Wed Dec  3 17:28:14 1997
+++ src/unexfreebsd.c	Wed Dec  3 17:34:02 1997
@@ -0,0 +1,692 @@
+/* Code to do an unexec for FreeBSD 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 <dirent.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 (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 0x%lx: %s\n", 
+		 sbrk_of_0_at_unexec, SYS_ERR);
+    }
+             
+  return 0;
+}