stuff.c

早期freebsd实现

/* Program to stuff files into a specially prepared space in kdb.
   Copyright (C) 1986, 1989, 1991 Free Software Foundation, Inc.

This file is part of GDB.

This program 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 of the License, or
(at your option) any later version.

This program 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 this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* Written 13-Mar-86 by David Bridgham. */

#include <stdio.h>
#include <a.out.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <varargs.h>

main (argc, argv)
     int argc;
     char *argv[];
{
  register char *cp;
  char *outfile;
  register int i;
  int offset;
  int out_fd, in_fd;
  struct stat stat_buf;
  int size, pad;
  char buf[1024];
  static char zeros[4] = {0};

  if (argc < 4)
    err("Not enough arguments\nUsage: %s -o kdb file1 file2 ...\n",
	argv[0]);

  outfile = 0;
  for (i = 1; i < argc; i++)
    {
      if (strcmp (argv[i], "-o") == 0)
	outfile = argv[++i];
    }
  if (outfile == 0)
    err("Output file not specified\n");

  offset = get_offset (outfile, "_heap");

  out_fd = open (outfile, O_WRONLY);
  if (out_fd < 0)
    err ("Error opening %s for write: %s\n", outfile, strerror (errno));
  if (lseek (out_fd, offset, 0) < 0)
    err ("Error seeking to heap in %s: %s\n", outfile, strerror (errno));

  /* For each file listed on the command line, write it into the
   * 'heap' of the output file.  Make sure to skip the arguments
   * that name the output file. */
  for (i = 1; i < argc; i++)
    {
      if (strcmp (argv[i], "-o") == 0)
	continue;
      if ((in_fd = open (argv[i], O_RDONLY)) < 0)
	err ("Error opening %s for read: %s\n", argv[i],
	     strerror (errno));
      if (fstat (in_fd, &stat_buf) < 0)
	err ("Error stat'ing %s: %s\n", argv[i], strerror (errno));
      size = strlen (argv[i]);
      pad = 4 - (size & 3);
      size += pad + stat_buf.st_size + sizeof (int);
      write (out_fd, &size, sizeof (int));
      write (out_fd, argv[i], strlen (argv[i]));
      write (out_fd, zeros, pad);
      while ((size = read (in_fd, buf, sizeof (buf))) > 0)
	write (out_fd, buf, size);
      close (in_fd);
    }
  size = 0;
  write (out_fd, &size, sizeof (int));
  close (out_fd);
  return (0);
}

/* Read symbol table from file and returns the offset into the file
 * where symbol sym_name is located.  If error, print message and
 * exit. */
get_offset (file, sym_name)
     char *file;
     char *sym_name;
{
  int f;
  struct exec file_hdr;
  struct nlist *symbol_table;
  int size;
  char *strings;

  f = open (file, O_RDONLY);
  if (f < 0)
    err ("Error opening %s: %s\n", file, strerror (errno));
  if (read (f, &file_hdr, sizeof (file_hdr)) < 0)
    err ("Error reading exec structure: %s\n", strerror (errno));
  if (N_BADMAG (file_hdr))
    err ("File %s not an a.out file\n", file);

  /* read in symbol table */
  if ((symbol_table = (struct nlist *)malloc (file_hdr.a_syms)) == 0)
    err ("Couldn't allocate space for symbol table\n");
  if (lseek (f, N_SYMOFF (file_hdr), 0) == -1)
    err ("lseek error: %s\n", strerror (errno));
  if (read (f, symbol_table, file_hdr.a_syms) == -1)
    err ("Error reading symbol table from %s: %s\n", file,
	 strerror (errno));

  /* read in string table */
  if (read (f, &size, 4) == -1)
    err ("reading string table size: %s\n", strerror (errno));
  if ((strings = (char *)malloc (size)) == 0)
    err ("Couldn't allocate memory for string table\n");
  if (read (f, strings, size - 4) == -1)
    err ("reading string table: %s\n", strerror (errno));

  /* Find the core address at which the first byte of kdb text segment
     should be loaded into core when kdb is run.  */
  origin = find_symbol ("_etext", symbol_table, file_hdr.a_syms, strings)
    - file_hdr.a_text;
  /* Find the core address at which the heap will appear.  */
  coreaddr = find_symbol (sym_name, symbol_table, file_hdr.a_syms, strings);
  /* Return address in file of the heap data space.  */
  return (N_TXTOFF (file_hdr) + core_addr - origin);
}

find_symbol (sym_name, symbol_table, length, strings)
     char *sym_name;
     struct nlist *symbol_table;
     int length;
     char *strings;
{
  register struct nlist *sym;

  /* Find symbol in question */
  for (sym = symbol_table;
       sym != (struct nlist *)((char *)symbol_table + length);
       sym++)
      {
	if ((sym->n_type & N_TYPE) != N_DATA) continue;
	if (sym->n_un.n_strx == 0) continue;
	if (strcmp (sym_name, strings + sym->n_un.n_strx - 4) == 0)
	  return sym->n_value;
      }
    err ("Data symbol %s not found in %s\n", sym_name, file);
}

/* VARARGS */
void
err (va_alist)
     va_dcl
{
  va_list args;
  char *string;

  va_start (args);
  string = va_arg (args, char *);
  vfprintf (stderr, string, args);
  va_end (args);
  exit (-1);
}