Restore file with clarified legal status.

1 files changed, 334 insertions, 0 deletions

diff --git a/src/unexhp9k800.c b/src/unexhp9k800.c
new file mode 100644
index 00000000000..495094029d6
--- /dev/null
+++ b/src/unexhp9k800.c
@@ -0,0 +1,334 @@
+/* Unexec for HP 9000 Series 800 machines.
+
+  This file is in the public domain.
+
+  Author: John V. Morris
+
+  This file was written by John V. Morris at Hewlett Packard.
+  Both the author and Hewlett Packard Co. have disclaimed the
+  copyright on this file, and it is therefore in the public domain.
+  (Search for "hp9k800" in copyright.list.)
+*/
+
+/*
+   Bob Desinger <hpsemc!bd@hplabs.hp.com>
+
+   Note that the GNU project considers support for HP operation a
+   peripheral activity which should not be allowed to divert effort
+   from development of the GNU system.  Changes in this code will be
+   installed when users send them in, but aside from that we don't
+   plan to think about it, or about whether other Emacs maintenance
+   might break it.
+
+
+  Unexec creates a copy of the old a.out file, and replaces the old data
+  area with the current data area.  When the new file is executed, the
+  process will see the same data structures and data values that the
+  original process had when unexec was called.
+
+  Unlike other versions of unexec, this one copies symbol table and
+  debug information to the new a.out file.  Thus, the new a.out file
+  may be debugged with symbolic debuggers.
+
+  If you fix any bugs in this, I'd like to incorporate your fixes.
+  Send them to uunet!hpda!hpsemc!jmorris or jmorris%hpsemc@hplabs.HP.COM.
+
+  CAVEATS:
+  This routine saves the current value of all static and external
+  variables.  This means that any data structure that needs to be
+  initialized must be explicitly reset.  Variables will not have their
+  expected default values.
+
+  Unfortunately, the HP-UX signal handler has internal initialization
+  flags which are not explicitly reset.  Thus, for signals to work in
+  conjunction with this routine, the following code must executed when
+  the new process starts up.
+
+  void _sigreturn ();
+  ...
+  sigsetreturn (_sigreturn);
+*/
+
+#ifdef emacs
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#include <a.out.h>
+
+#ifdef HPUX_USE_SHLIBS
+#include <dl.h>
+#endif
+
+/* brk value to restore, stored as a global.
+   This is really used only if we used shared libraries.  */
+static long brk_on_dump = 0;
+
+/* Called from main, if we use shared libraries.  */
+int
+run_time_remap (ignored)
+     char *ignored;
+{
+  brk ((char *) brk_on_dump);
+}
+
+#undef roundup
+#define roundup(x,n) (((x) + ((n) - 1)) & ~((n) - 1))  /* n is power of 2 */
+#define min(x,y)  (((x) < (y)) ? (x) : (y))
+
+
+/* Create a new a.out file, same as old but with current data space */
+
+unexec (new_name, old_name, new_end_of_text, dummy1, dummy2)
+     char new_name[];		/* name of the new a.out file to be created */
+     char old_name[];		/* name of the old a.out file */
+     char *new_end_of_text;	/* ptr to new edata/etext; NOT USED YET */
+     int dummy1, dummy2;	/* not used by emacs */
+{
+  int old, new;
+  int old_size, new_size;
+  struct header hdr;
+  struct som_exec_auxhdr auxhdr;
+  long i;
+
+  /* For the greatest flexibility, should create a temporary file in
+     the same directory as the new file.  When everything is complete,
+     rename the temp file to the new name.
+     This way, a program could update its own a.out file even while
+     it is still executing.  If problems occur, everything is still
+     intact.  NOT implemented.  */
+
+  /* Open the input and output a.out files */
+  old = open (old_name, O_RDONLY);
+  if (old < 0)
+    { perror (old_name); exit (1); }
+  new = open (new_name, O_CREAT|O_RDWR|O_TRUNC, 0777);
+  if (new < 0)
+    { perror (new_name); exit (1); }
+
+  /* Read the old headers */
+  read_header (old, &hdr, &auxhdr);
+
+  brk_on_dump = (long) sbrk (0);
+
+  /* Decide how large the new and old data areas are */
+  old_size = auxhdr.exec_dsize;
+  /* I suspect these two statements are separate
+     to avoid a compiler bug in hpux version 8.  */
+  i = (long) sbrk (0);
+  new_size = i - auxhdr.exec_dmem;
+
+  /* Copy the old file to the new, up to the data space */
+  lseek (old, 0, 0);
+  copy_file (old, new, auxhdr.exec_dfile);
+
+  /* Skip the old data segment and write a new one */
+  lseek (old, old_size, 1);
+  save_data_space (new, &hdr, &auxhdr, new_size);
+
+  /* Copy the rest of the file */
+  copy_rest (old, new);
+
+  /* Update file pointers since we probably changed size of data area */
+  update_file_ptrs (new, &hdr, &auxhdr, auxhdr.exec_dfile, new_size-old_size);
+
+  /* Save the modified header */
+  write_header (new, &hdr, &auxhdr);
+
+  /* Close the binary file */
+  close (old);
+  close (new);
+  return 0;
+}
+
+/* Save current data space in the file, update header.  */
+
+save_data_space (file, hdr, auxhdr, size)
+     int file;
+     struct header *hdr;
+     struct som_exec_auxhdr *auxhdr;
+     int size;
+{
+  /* Write the entire data space out to the file */
+  if (write (file, auxhdr->exec_dmem, size) != size)
+    { perror ("Can't save new data space"); exit (1); }
+
+  /* Update the header to reflect the new data size */
+  auxhdr->exec_dsize = size;
+  auxhdr->exec_bsize = 0;
+}
+
+/* Update the values of file pointers when something is inserted.  */
+
+update_file_ptrs (file, hdr, auxhdr, location, offset)
+     int file;
+     struct header *hdr;
+     struct som_exec_auxhdr *auxhdr;
+     unsigned int location;
+     int offset;
+{
+  struct subspace_dictionary_record subspace;
+  int i;
+
+  /* Increase the overall size of the module */
+  hdr->som_length += offset;
+
+  /* Update the various file pointers in the header */
+#define update(ptr) if (ptr > location) ptr = ptr + offset
+  update (hdr->aux_header_location);
+  update (hdr->space_strings_location);
+  update (hdr->init_array_location);
+  update (hdr->compiler_location);
+  update (hdr->symbol_location);
+  update (hdr->fixup_request_location);
+  update (hdr->symbol_strings_location);
+  update (hdr->unloadable_sp_location);
+  update (auxhdr->exec_tfile);
+  update (auxhdr->exec_dfile);
+
+  /* Do for each subspace dictionary entry */
+  lseek (file, hdr->subspace_location, 0);
+  for (i = 0; i < hdr->subspace_total; i++)
+    {
+      if (read (file, &subspace, sizeof (subspace)) != sizeof (subspace))
+	{ perror ("Can't read subspace record"); exit (1); }
+
+      /* If subspace has a file location, update it */
+      if (subspace.initialization_length > 0
+	  && subspace.file_loc_init_value > location)
+	{
+	  subspace.file_loc_init_value += offset;
+	  lseek (file, -sizeof (subspace), 1);
+	  if (write (file, &subspace, sizeof (subspace)) != sizeof (subspace))
+	    { perror ("Can't update subspace record"); exit (1); }
+	}
+    }
+
+  /* Do for each initialization pointer record */
+  /* (I don't think it applies to executable files, only relocatables) */
+#undef update
+}
+
+/* Read in the header records from an a.out file.  */
+
+read_header (file, hdr, auxhdr)
+     int file;
+     struct header *hdr;
+     struct som_exec_auxhdr *auxhdr;
+{
+
+  /* Read the header in */
+  lseek (file, 0, 0);
+  if (read (file, hdr, sizeof (*hdr)) != sizeof (*hdr))
+    { perror ("Couldn't read header from a.out file"); exit (1); }
+
+  if (hdr->a_magic != EXEC_MAGIC && hdr->a_magic != SHARE_MAGIC
+      &&  hdr->a_magic != DEMAND_MAGIC)
+    {
+      fprintf (stderr, "a.out file doesn't have legal magic number\n");
+      exit (1);
+    }
+
+  lseek (file, hdr->aux_header_location, 0);
+  if (read (file, auxhdr, sizeof (*auxhdr)) != sizeof (*auxhdr))
+    {
+      perror ("Couldn't read auxiliary header from a.out file");
+      exit (1);
+    }
+}
+
+/* Write out the header records into an a.out file.  */
+
+write_header (file, hdr, auxhdr)
+     int file;
+     struct header *hdr;
+     struct som_exec_auxhdr *auxhdr;
+{
+  /* Update the checksum */
+  hdr->checksum = calculate_checksum (hdr);
+
+  /* Write the header back into the a.out file */
+  lseek (file, 0, 0);
+  if (write (file, hdr, sizeof (*hdr)) != sizeof (*hdr))
+    { perror ("Couldn't write header to a.out file"); exit (1); }
+  lseek (file, hdr->aux_header_location, 0);
+  if (write (file, auxhdr, sizeof (*auxhdr)) != sizeof (*auxhdr))
+    { perror ("Couldn't write auxiliary header to a.out file"); exit (1); }
+}
+
+/* Calculate the checksum of a SOM header record. */
+
+calculate_checksum (hdr)
+     struct header *hdr;
+{
+  int checksum, i, *ptr;
+
+  checksum = 0;  ptr = (int *) hdr;
+
+  for (i = 0; i < sizeof (*hdr) / sizeof (int) - 1; i++)
+    checksum ^= ptr[i];
+
+  return (checksum);
+}
+
+/* Copy size bytes from the old file to the new one.  */
+
+copy_file (old, new, size)
+     int new, old;
+     int size;
+{
+  int len;
+  int buffer[8192];  /* word aligned will be faster */
+
+  for (; size > 0; size -= len)
+    {
+      len = min (size, sizeof (buffer));
+      if (read (old, buffer, len) != len)
+	{ perror ("Read failure on a.out file"); exit (1); }
+      if (write (new, buffer, len) != len)
+	{ perror ("Write failure in a.out file"); exit (1); }
+    }
+}
+
+/* Copy the rest of the file, up to EOF.  */
+
+copy_rest (old, new)
+     int new, old;
+{
+  int buffer[4096];
+  int len;
+
+  /* Copy bytes until end of file or error */
+  while ((len = read (old, buffer, sizeof (buffer))) > 0)
+    if (write (new, buffer, len) != len) break;
+
+  if (len != 0)
+    { perror ("Unable to copy the rest of the file"); exit (1); }
+}
+
+#ifdef	DEBUG
+display_header (hdr, auxhdr)
+     struct header *hdr;
+     struct som_exec_auxhdr *auxhdr;
+{
+  /* Display the header information (debug) */
+  printf ("\n\nFILE HEADER\n");
+  printf ("magic number %d \n", hdr->a_magic);
+  printf ("text loc %.8x   size %d \n", auxhdr->exec_tmem, auxhdr->exec_tsize);
+  printf ("data loc %.8x   size %d \n", auxhdr->exec_dmem, auxhdr->exec_dsize);
+  printf ("entry     %x \n",   auxhdr->exec_entry);
+  printf ("Bss  segment size %u\n", auxhdr->exec_bsize);
+  printf ("\n");
+  printf ("data file loc %d    size %d\n",
+	  auxhdr->exec_dfile, auxhdr->exec_dsize);
+  printf ("som_length %d\n", hdr->som_length);
+  printf ("unloadable sploc %d    size %d\n",
+	  hdr->unloadable_sp_location, hdr->unloadable_sp_size);
+}
+#endif /* DEBUG */
+
+/* arch-tag: d55a09ac-9427-4ec4-8496-cb9d7710774f
+   (do not change this comment) */