Restore file with clarified legal status.
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Glenn Morris
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ce545621d2
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1 changed files with 334 additions and 0 deletions
334
src/unexhp9k800.c
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334
src/unexhp9k800.c
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/* Unexec for HP 9000 Series 800 machines.
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This file is in the public domain.
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Author: John V. Morris
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This file was written by John V. Morris at Hewlett Packard.
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Both the author and Hewlett Packard Co. have disclaimed the
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copyright on this file, and it is therefore in the public domain.
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(Search for "hp9k800" in copyright.list.)
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*/
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/*
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Bob Desinger <hpsemc!bd@hplabs.hp.com>
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Note that the GNU project considers support for HP operation a
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peripheral activity which should not be allowed to divert effort
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from development of the GNU system. Changes in this code will be
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installed when users send them in, but aside from that we don't
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plan to think about it, or about whether other Emacs maintenance
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might break it.
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Unexec creates a copy of the old a.out file, and replaces the old data
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area with the current data area. When the new file is executed, the
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process will see the same data structures and data values that the
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original process had when unexec was called.
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Unlike other versions of unexec, this one copies symbol table and
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debug information to the new a.out file. Thus, the new a.out file
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may be debugged with symbolic debuggers.
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If you fix any bugs in this, I'd like to incorporate your fixes.
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Send them to uunet!hpda!hpsemc!jmorris or jmorris%hpsemc@hplabs.HP.COM.
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CAVEATS:
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This routine saves the current value of all static and external
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variables. This means that any data structure that needs to be
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initialized must be explicitly reset. Variables will not have their
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expected default values.
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Unfortunately, the HP-UX signal handler has internal initialization
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flags which are not explicitly reset. Thus, for signals to work in
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conjunction with this routine, the following code must executed when
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the new process starts up.
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void _sigreturn ();
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...
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sigsetreturn (_sigreturn);
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*/
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#ifdef emacs
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#include <config.h>
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#endif
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#include <stdio.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <a.out.h>
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#ifdef HPUX_USE_SHLIBS
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#include <dl.h>
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#endif
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/* brk value to restore, stored as a global.
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This is really used only if we used shared libraries. */
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static long brk_on_dump = 0;
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/* Called from main, if we use shared libraries. */
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int
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run_time_remap (ignored)
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char *ignored;
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{
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brk ((char *) brk_on_dump);
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}
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#undef roundup
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#define roundup(x,n) (((x) + ((n) - 1)) & ~((n) - 1)) /* n is power of 2 */
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#define min(x,y) (((x) < (y)) ? (x) : (y))
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/* Create a new a.out file, same as old but with current data space */
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unexec (new_name, old_name, new_end_of_text, dummy1, dummy2)
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char new_name[]; /* name of the new a.out file to be created */
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char old_name[]; /* name of the old a.out file */
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char *new_end_of_text; /* ptr to new edata/etext; NOT USED YET */
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int dummy1, dummy2; /* not used by emacs */
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{
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int old, new;
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int old_size, new_size;
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struct header hdr;
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struct som_exec_auxhdr auxhdr;
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long i;
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/* For the greatest flexibility, should create a temporary file in
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the same directory as the new file. When everything is complete,
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rename the temp file to the new name.
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This way, a program could update its own a.out file even while
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it is still executing. If problems occur, everything is still
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intact. NOT implemented. */
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/* Open the input and output a.out files */
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old = open (old_name, O_RDONLY);
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if (old < 0)
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{ perror (old_name); exit (1); }
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new = open (new_name, O_CREAT|O_RDWR|O_TRUNC, 0777);
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if (new < 0)
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{ perror (new_name); exit (1); }
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/* Read the old headers */
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read_header (old, &hdr, &auxhdr);
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brk_on_dump = (long) sbrk (0);
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/* Decide how large the new and old data areas are */
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old_size = auxhdr.exec_dsize;
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/* I suspect these two statements are separate
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to avoid a compiler bug in hpux version 8. */
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i = (long) sbrk (0);
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new_size = i - auxhdr.exec_dmem;
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/* Copy the old file to the new, up to the data space */
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lseek (old, 0, 0);
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copy_file (old, new, auxhdr.exec_dfile);
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/* Skip the old data segment and write a new one */
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lseek (old, old_size, 1);
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save_data_space (new, &hdr, &auxhdr, new_size);
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/* Copy the rest of the file */
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copy_rest (old, new);
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/* Update file pointers since we probably changed size of data area */
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update_file_ptrs (new, &hdr, &auxhdr, auxhdr.exec_dfile, new_size-old_size);
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/* Save the modified header */
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write_header (new, &hdr, &auxhdr);
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/* Close the binary file */
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close (old);
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close (new);
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return 0;
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}
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/* Save current data space in the file, update header. */
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save_data_space (file, hdr, auxhdr, size)
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int file;
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struct header *hdr;
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struct som_exec_auxhdr *auxhdr;
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int size;
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{
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/* Write the entire data space out to the file */
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if (write (file, auxhdr->exec_dmem, size) != size)
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{ perror ("Can't save new data space"); exit (1); }
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/* Update the header to reflect the new data size */
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auxhdr->exec_dsize = size;
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auxhdr->exec_bsize = 0;
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}
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/* Update the values of file pointers when something is inserted. */
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update_file_ptrs (file, hdr, auxhdr, location, offset)
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int file;
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struct header *hdr;
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struct som_exec_auxhdr *auxhdr;
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unsigned int location;
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int offset;
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{
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struct subspace_dictionary_record subspace;
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int i;
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/* Increase the overall size of the module */
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hdr->som_length += offset;
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/* Update the various file pointers in the header */
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#define update(ptr) if (ptr > location) ptr = ptr + offset
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update (hdr->aux_header_location);
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update (hdr->space_strings_location);
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update (hdr->init_array_location);
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update (hdr->compiler_location);
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update (hdr->symbol_location);
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update (hdr->fixup_request_location);
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update (hdr->symbol_strings_location);
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update (hdr->unloadable_sp_location);
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update (auxhdr->exec_tfile);
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update (auxhdr->exec_dfile);
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/* Do for each subspace dictionary entry */
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lseek (file, hdr->subspace_location, 0);
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for (i = 0; i < hdr->subspace_total; i++)
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{
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if (read (file, &subspace, sizeof (subspace)) != sizeof (subspace))
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{ perror ("Can't read subspace record"); exit (1); }
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/* If subspace has a file location, update it */
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if (subspace.initialization_length > 0
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&& subspace.file_loc_init_value > location)
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{
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subspace.file_loc_init_value += offset;
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lseek (file, -sizeof (subspace), 1);
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if (write (file, &subspace, sizeof (subspace)) != sizeof (subspace))
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{ perror ("Can't update subspace record"); exit (1); }
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}
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}
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/* Do for each initialization pointer record */
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/* (I don't think it applies to executable files, only relocatables) */
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#undef update
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}
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/* Read in the header records from an a.out file. */
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read_header (file, hdr, auxhdr)
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int file;
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struct header *hdr;
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struct som_exec_auxhdr *auxhdr;
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{
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/* Read the header in */
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lseek (file, 0, 0);
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if (read (file, hdr, sizeof (*hdr)) != sizeof (*hdr))
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{ perror ("Couldn't read header from a.out file"); exit (1); }
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if (hdr->a_magic != EXEC_MAGIC && hdr->a_magic != SHARE_MAGIC
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&& hdr->a_magic != DEMAND_MAGIC)
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{
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fprintf (stderr, "a.out file doesn't have legal magic number\n");
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exit (1);
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}
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lseek (file, hdr->aux_header_location, 0);
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if (read (file, auxhdr, sizeof (*auxhdr)) != sizeof (*auxhdr))
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{
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perror ("Couldn't read auxiliary header from a.out file");
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exit (1);
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}
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}
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/* Write out the header records into an a.out file. */
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write_header (file, hdr, auxhdr)
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int file;
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struct header *hdr;
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struct som_exec_auxhdr *auxhdr;
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{
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/* Update the checksum */
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hdr->checksum = calculate_checksum (hdr);
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/* Write the header back into the a.out file */
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lseek (file, 0, 0);
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if (write (file, hdr, sizeof (*hdr)) != sizeof (*hdr))
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{ perror ("Couldn't write header to a.out file"); exit (1); }
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lseek (file, hdr->aux_header_location, 0);
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if (write (file, auxhdr, sizeof (*auxhdr)) != sizeof (*auxhdr))
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{ perror ("Couldn't write auxiliary header to a.out file"); exit (1); }
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}
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/* Calculate the checksum of a SOM header record. */
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calculate_checksum (hdr)
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struct header *hdr;
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{
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int checksum, i, *ptr;
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checksum = 0; ptr = (int *) hdr;
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for (i = 0; i < sizeof (*hdr) / sizeof (int) - 1; i++)
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checksum ^= ptr[i];
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return (checksum);
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}
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/* Copy size bytes from the old file to the new one. */
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copy_file (old, new, size)
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int new, old;
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int size;
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{
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int len;
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int buffer[8192]; /* word aligned will be faster */
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for (; size > 0; size -= len)
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{
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len = min (size, sizeof (buffer));
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if (read (old, buffer, len) != len)
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{ perror ("Read failure on a.out file"); exit (1); }
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if (write (new, buffer, len) != len)
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{ perror ("Write failure in a.out file"); exit (1); }
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}
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}
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/* Copy the rest of the file, up to EOF. */
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copy_rest (old, new)
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int new, old;
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{
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int buffer[4096];
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int len;
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/* Copy bytes until end of file or error */
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while ((len = read (old, buffer, sizeof (buffer))) > 0)
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if (write (new, buffer, len) != len) break;
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if (len != 0)
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{ perror ("Unable to copy the rest of the file"); exit (1); }
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}
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#ifdef DEBUG
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display_header (hdr, auxhdr)
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struct header *hdr;
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struct som_exec_auxhdr *auxhdr;
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{
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/* Display the header information (debug) */
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printf ("\n\nFILE HEADER\n");
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printf ("magic number %d \n", hdr->a_magic);
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printf ("text loc %.8x size %d \n", auxhdr->exec_tmem, auxhdr->exec_tsize);
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printf ("data loc %.8x size %d \n", auxhdr->exec_dmem, auxhdr->exec_dsize);
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printf ("entry %x \n", auxhdr->exec_entry);
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printf ("Bss segment size %u\n", auxhdr->exec_bsize);
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printf ("\n");
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printf ("data file loc %d size %d\n",
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auxhdr->exec_dfile, auxhdr->exec_dsize);
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printf ("som_length %d\n", hdr->som_length);
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printf ("unloadable sploc %d size %d\n",
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hdr->unloadable_sp_location, hdr->unloadable_sp_size);
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}
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#endif /* DEBUG */
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/* arch-tag: d55a09ac-9427-4ec4-8496-cb9d7710774f
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(do not change this comment) */
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