Initial revision

1 files changed, 762 insertions, 0 deletions

diff --git a/gdb/exec.c b/gdb/exec.c
new file mode 100644
index 00000000000..87aed010f01
--- /dev/null
+++ b/gdb/exec.c
@@ -0,0 +1,762 @@
+/* Work with executable files, for GDB. 
+   Copyright 1988, 1989, 1991, 1992, 1993, 1994, 1997, 1998
+             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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+#include "defs.h"
+#include "frame.h"
+#include "inferior.h"
+#include "target.h"
+#include "gdbcmd.h"
+#include "language.h"
+#include "symfile.h"
+#include "objfiles.h"
+
+#ifdef USG
+#include <sys/types.h>
+#endif
+
+#include <fcntl.h>
+#include "gdb_string.h"
+
+#include "gdbcore.h"
+
+#include <ctype.h>
+#include "gdb_stat.h"
+#ifndef O_BINARY
+#define O_BINARY 0
+#endif
+
+#include "xcoffsolib.h"
+
+struct vmap *map_vmap PARAMS ((bfd *, bfd *));
+
+void (*file_changed_hook) PARAMS ((char *));
+
+/* Prototypes for local functions */
+
+static void add_to_section_table PARAMS ((bfd *, sec_ptr, PTR));
+
+static void exec_close PARAMS ((int));
+
+static void file_command PARAMS ((char *, int));
+
+static void set_section_command PARAMS ((char *, int));
+
+static void exec_files_info PARAMS ((struct target_ops *));
+
+static void bfdsec_to_vmap PARAMS ((bfd *, sec_ptr, PTR));
+
+static int ignore PARAMS ((CORE_ADDR, char *));
+
+static void init_exec_ops PARAMS ((void));
+
+void _initialize_exec PARAMS ((void));
+
+extern int info_verbose;
+
+/* The target vector for executable files.  */
+
+struct target_ops exec_ops;
+
+/* The Binary File Descriptor handle for the executable file.  */
+
+bfd *exec_bfd = NULL;
+
+/* Whether to open exec and core files read-only or read-write.  */
+
+int write_files = 0;
+
+/* Text start and end addresses (KLUDGE) if needed */
+
+#ifndef NEED_TEXT_START_END
+#define NEED_TEXT_START_END (0)
+#endif
+CORE_ADDR text_start = 0;
+CORE_ADDR text_end   = 0;
+
+struct vmap *vmap;
+
+/* ARGSUSED */
+static void
+exec_close (quitting)
+     int quitting;
+{
+  int need_symtab_cleanup = 0;
+  struct vmap *vp, *nxt;
+  
+  for (nxt = vmap; nxt != NULL; )
+    {
+      vp = nxt;
+      nxt = vp->nxt;
+
+      /* if there is an objfile associated with this bfd,
+	 free_objfile() will do proper cleanup of objfile *and* bfd. */
+		   
+      if (vp->objfile)
+	{
+	  free_objfile (vp->objfile);
+	  need_symtab_cleanup = 1;
+	}
+      else if (vp->bfd != exec_bfd)
+	/* FIXME-leak: We should be freeing vp->name too, I think.  */
+	if (!bfd_close (vp->bfd))
+	  warning ("cannot close \"%s\": %s",
+		   vp->name, bfd_errmsg (bfd_get_error ()));
+
+      /* FIXME: This routine is #if 0'd in symfile.c.  What should we
+	 be doing here?  Should we just free everything in
+	 vp->objfile->symtabs?  Should free_objfile do that?
+	 FIXME-as-well: free_objfile already free'd vp->name, so it isn't
+	 valid here.  */
+      free_named_symtabs (vp->name);
+      free (vp);
+    }
+
+  vmap = NULL;
+
+  if (exec_bfd)
+    {
+      char *name = bfd_get_filename (exec_bfd);
+
+      if (!bfd_close (exec_bfd))
+	warning ("cannot close \"%s\": %s",
+		 name, bfd_errmsg (bfd_get_error ()));
+      free (name);
+      exec_bfd = NULL;
+    }
+
+  if (exec_ops.to_sections)
+    {
+      free ((PTR)exec_ops.to_sections);
+      exec_ops.to_sections = NULL;
+      exec_ops.to_sections_end = NULL;
+    }
+}
+
+/*  Process the first arg in ARGS as the new exec file.
+
+    This function is intended to be behave essentially the same
+    as exec_file_command, except that the latter will detect when
+    a target is being debugged, and will ask the user whether it
+    should be shut down first.  (If the answer is "no", then the
+    new file is ignored.)
+
+    This file is used by exec_file_command, to do the work of opening
+    and processing the exec file after any prompting has happened.
+
+    And, it is used by child_attach, when the attach command was
+    given a pid but not a exec pathname, and the attach command could
+    figure out the pathname from the pid.  (In this case, we shouldn't
+    ask the user whether the current target should be shut down --
+    we're supplying the exec pathname late for good reason.) */
+
+void
+exec_file_attach (args, from_tty)
+     char *args;
+     int from_tty;
+{
+  char **argv;
+  char *filename;
+
+  /* Remove any previous exec file.  */
+  unpush_target (&exec_ops);
+
+  /* Now open and digest the file the user requested, if any.  */
+
+  if (args)
+    {
+      char *scratch_pathname;
+      int scratch_chan;
+      
+      /* Scan through the args and pick up the first non option arg
+	 as the filename.  */
+
+      argv = buildargv (args);
+      if (argv == NULL)
+	nomem (0);
+
+      make_cleanup ((make_cleanup_func) freeargv, (char *) argv);
+
+      for (; (*argv != NULL) && (**argv == '-'); argv++) {;}
+      if (*argv == NULL)
+	error ("no exec file name was specified");
+
+      filename = tilde_expand (*argv);
+      make_cleanup (free, filename);
+      
+      scratch_chan = openp (getenv ("PATH"), 1, filename, 
+			    write_files? O_RDWR|O_BINARY: O_RDONLY|O_BINARY, 0,
+			    &scratch_pathname);
+#if defined(__GO32__) || defined(_WIN32)
+      if (scratch_chan < 0)
+      {
+	char *exename = alloca (strlen (filename) + 5);
+	strcat (strcpy (exename, filename), ".exe");
+	scratch_chan = openp (getenv ("PATH"), 1, exename, write_files ?
+		O_RDWR|O_BINARY : O_RDONLY|O_BINARY, 0, &scratch_pathname);
+      }
+#endif
+      if (scratch_chan < 0)
+	perror_with_name (filename);
+      exec_bfd = bfd_fdopenr (scratch_pathname, gnutarget, scratch_chan);
+
+      if (!exec_bfd)
+	error ("\"%s\": could not open as an executable file: %s",
+	       scratch_pathname, bfd_errmsg (bfd_get_error ()));
+
+      /* At this point, scratch_pathname and exec_bfd->name both point to the
+	 same malloc'd string.  However exec_close() will attempt to free it
+	 via the exec_bfd->name pointer, so we need to make another copy and
+	 leave exec_bfd as the new owner of the original copy. */
+      scratch_pathname = strdup (scratch_pathname);
+      make_cleanup (free, scratch_pathname);
+      
+      if (!bfd_check_format (exec_bfd, bfd_object))
+	{
+	  /* Make sure to close exec_bfd, or else "run" might try to use
+	     it.  */
+	  exec_close (0);
+	  error ("\"%s\": not in executable format: %s",
+		 scratch_pathname, bfd_errmsg (bfd_get_error ()));
+	}
+
+      /* FIXME - This should only be run for RS6000, but the ifdef is a poor
+	 way to accomplish.  */
+#ifdef IBM6000_TARGET
+      /* Setup initial vmap. */
+
+      map_vmap (exec_bfd, 0);
+      if (vmap == NULL)
+	{
+	  /* Make sure to close exec_bfd, or else "run" might try to use
+	     it.  */
+	  exec_close (0);
+	  error ("\"%s\": can't find the file sections: %s",
+		 scratch_pathname, bfd_errmsg (bfd_get_error ()));
+	}
+#endif /* IBM6000_TARGET */
+
+      if (build_section_table (exec_bfd, &exec_ops.to_sections,
+				&exec_ops.to_sections_end))
+	{
+	  /* Make sure to close exec_bfd, or else "run" might try to use
+	     it.  */
+	  exec_close (0);
+	  error ("\"%s\": can't find the file sections: %s", 
+		 scratch_pathname, bfd_errmsg (bfd_get_error ()));
+	}
+
+      /* text_end is sometimes used for where to put call dummies.  A
+	 few ports use these for other purposes too.  */
+      if (NEED_TEXT_START_END)
+	{
+	  struct section_table *p;
+	  
+	  /* Set text_start to the lowest address of the start of any
+	     readonly code section and set text_end to the highest
+	     address of the end of any readonly code section.  */
+	  /* FIXME: The comment above does not match the code.  The
+	     code checks for sections with are either code *or*
+	     readonly.  */
+	  text_start = ~(CORE_ADDR)0;
+	  text_end = (CORE_ADDR)0;
+	  for (p = exec_ops.to_sections; p < exec_ops.to_sections_end; p++)
+	    if (bfd_get_section_flags (p->bfd, p->the_bfd_section)
+		& (SEC_CODE | SEC_READONLY))
+	      {
+		if (text_start > p->addr) 
+		  text_start = p->addr;
+		if (text_end < p->endaddr)
+		  text_end = p->endaddr;
+	      }
+	}
+
+      validate_files ();
+
+      set_gdbarch_from_file (exec_bfd);
+
+      push_target (&exec_ops);
+
+      /* Tell display code (if any) about the changed file name.  */
+      if (exec_file_display_hook)
+	(*exec_file_display_hook) (filename);
+    }
+  else if (from_tty)
+    printf_unfiltered ("No executable file now.\n");
+}
+
+/*  Process the first arg in ARGS as the new exec file.
+
+    Note that we have to explicitly ignore additional args, since we can
+    be called from file_command(), which also calls symbol_file_command()
+    which can take multiple args. */
+
+void
+exec_file_command (args, from_tty)
+     char *args;
+     int from_tty;
+{
+  char **argv;
+  char *filename;
+
+  target_preopen (from_tty);
+
+  exec_file_attach (args, from_tty);
+}
+
+/* Set both the exec file and the symbol file, in one command.  
+   What a novelty.  Why did GDB go through four major releases before this
+   command was added?  */
+
+static void
+file_command (arg, from_tty)
+     char *arg;
+     int from_tty;
+{
+  /* FIXME, if we lose on reading the symbol file, we should revert
+     the exec file, but that's rough.  */
+  exec_file_command (arg, from_tty);
+  symbol_file_command (arg, from_tty);
+  if (file_changed_hook)
+    file_changed_hook (arg);
+}
+
+
+/* Locate all mappable sections of a BFD file. 
+   table_pp_char is a char * to get it through bfd_map_over_sections;
+   we cast it back to its proper type.  */
+
+static void
+add_to_section_table (abfd, asect, table_pp_char)
+     bfd *abfd;
+     sec_ptr asect;
+     PTR table_pp_char;
+{
+  struct section_table **table_pp = (struct section_table **)table_pp_char;
+  flagword aflag;
+
+  aflag = bfd_get_section_flags (abfd, asect);
+  if (!(aflag & SEC_ALLOC))
+    return;
+  if (0 == bfd_section_size (abfd, asect))
+    return;
+  (*table_pp)->bfd = abfd;
+  (*table_pp)->the_bfd_section = asect;
+  (*table_pp)->addr = bfd_section_vma (abfd, asect);
+  (*table_pp)->endaddr = (*table_pp)->addr + bfd_section_size (abfd, asect);
+  (*table_pp)++;
+}
+
+/* Builds a section table, given args BFD, SECTABLE_PTR, SECEND_PTR.
+   Returns 0 if OK, 1 on error.  */
+
+int
+build_section_table (some_bfd, start, end)
+     bfd *some_bfd;
+     struct section_table **start, **end;
+{
+  unsigned count;
+
+  count = bfd_count_sections (some_bfd);
+  if (*start)
+    free ((PTR)*start);
+  *start = (struct section_table *) xmalloc (count * sizeof (**start));
+  *end = *start;
+  bfd_map_over_sections (some_bfd, add_to_section_table, (char *)end);
+  if (*end > *start + count)
+    abort();
+  /* We could realloc the table, but it probably loses for most files.  */
+  return 0;
+}
+
+static void
+bfdsec_to_vmap(abfd, sect, arg3) 
+     bfd *abfd;
+     sec_ptr sect;
+     PTR arg3;
+{
+  struct vmap_and_bfd *vmap_bfd = (struct vmap_and_bfd *) arg3;
+  struct vmap *vp;
+
+  vp = vmap_bfd->pvmap;
+
+  if ((bfd_get_section_flags (abfd, sect) & SEC_LOAD) == 0)
+    return;
+
+  if (STREQ (bfd_section_name (abfd, sect), ".text"))
+    {
+      vp->tstart = bfd_section_vma (abfd, sect);
+      vp->tend = vp->tstart + bfd_section_size (abfd, sect);
+      vp->tvma = bfd_section_vma (abfd, sect);
+      vp->toffs = sect->filepos;
+    }
+  else if (STREQ (bfd_section_name (abfd, sect), ".data"))
+    {
+      vp->dstart = bfd_section_vma (abfd, sect);
+      vp->dend = vp->dstart + bfd_section_size (abfd, sect);
+      vp->dvma = bfd_section_vma (abfd, sect);
+    }
+  /* Silently ignore other types of sections. (FIXME?)  */
+}
+
+/* Make a vmap for ABFD which might be a member of the archive ARCH.
+   Return the new vmap.  */
+
+struct vmap *
+map_vmap (abfd, arch)
+     bfd *abfd;
+     bfd *arch;
+{
+  struct vmap_and_bfd vmap_bfd;
+  struct vmap *vp, **vpp;
+
+  vp = (struct vmap *) xmalloc (sizeof (*vp));
+  memset ((char *) vp, '\0', sizeof (*vp));
+  vp->nxt = 0;
+  vp->bfd = abfd;
+  vp->name = bfd_get_filename (arch ? arch : abfd);
+  vp->member = arch ? bfd_get_filename (abfd) : "";
+  
+  vmap_bfd.pbfd = arch;
+  vmap_bfd.pvmap = vp;
+  bfd_map_over_sections (abfd, bfdsec_to_vmap, &vmap_bfd);
+
+  /* Find the end of the list and append. */
+  for (vpp = &vmap; *vpp; vpp = &(*vpp)->nxt)
+    ;
+  *vpp = vp;
+
+  return vp;
+}
+
+/* Read or write the exec file.
+
+   Args are address within a BFD file, address within gdb address-space,
+   length, and a flag indicating whether to read or write.
+
+   Result is a length:
+
+	0:    We cannot handle this address and length.
+	> 0:  We have handled N bytes starting at this address.
+	      (If N == length, we did it all.)  We might be able
+	      to handle more bytes beyond this length, but no
+	      promises.
+	< 0:  We cannot handle this address, but if somebody
+	      else handles (-N) bytes, we can start from there.
+
+    The same routine is used to handle both core and exec files;
+    we just tail-call it with more arguments to select between them.  */
+
+int
+xfer_memory (memaddr, myaddr, len, write, target)
+     CORE_ADDR memaddr;
+     char *myaddr;
+     int len;
+     int write;
+     struct target_ops *target;
+{
+  boolean res;
+  struct section_table *p;
+  CORE_ADDR nextsectaddr, memend;
+  boolean (*xfer_fn) PARAMS ((bfd *, sec_ptr, PTR, file_ptr, bfd_size_type));
+  asection *section;
+
+  if (len <= 0)
+    abort();
+
+  if (overlay_debugging)
+    {
+      section = find_pc_overlay (memaddr);
+      if (pc_in_unmapped_range (memaddr, section))
+	memaddr = overlay_mapped_address (memaddr, section);
+    }
+
+  memend = memaddr + len;
+  xfer_fn = write ? bfd_set_section_contents : bfd_get_section_contents;
+  nextsectaddr = memend;
+
+#if 0 /* Stu's implementation */
+/* If a section has been specified, try to use it.  Note that we cannot use the
+   specified section directly.  This is because it usually comes from the
+   symbol file, which may be different from the exec or core file.  Instead, we
+   have to lookup the specified section by name in the bfd associated with
+   to_sections.  */
+
+  if (target_memory_bfd_section)
+    {
+      asection *s;
+      bfd *abfd;
+      asection *target_section;
+      bfd *target_bfd;
+
+      s = target_memory_bfd_section;
+      abfd = s->owner;
+
+      target_bfd = target->to_sections->bfd;
+      target_section = bfd_get_section_by_name (target_bfd, bfd_section_name (abfd, s));
+
+      if (target_section)
+	{
+	  bfd_vma sec_addr;
+	  bfd_size_type sec_size;
+
+	  sec_addr = bfd_section_vma (target_bfd, target_section);
+	  sec_size = target_section->_raw_size;
+
+	  /* Make sure the requested memory starts inside the section.  */
+
+	  if (memaddr >= sec_addr
+	      && memaddr < sec_addr + sec_size)
+	    {
+	      /* Cut back length in case request overflows the end of the section. */
+	      len = min (len, sec_addr + sec_size - memaddr);
+
+	      res = xfer_fn (target_bfd, target_section, myaddr, memaddr - sec_addr, len);
+
+	      return res ? len : 0;
+	    }
+	}
+    }
+#endif /* 0, Stu's implementation */
+  for (p = target->to_sections; p < target->to_sections_end; p++)
+    {
+      if (overlay_debugging && section && p->the_bfd_section &&
+	  strcmp (section->name, p->the_bfd_section->name) != 0)
+	continue;	/* not the section we need */
+      if (memaddr >= p->addr)
+ 	if (memend <= p->endaddr)
+	  {
+	    /* Entire transfer is within this section.  */
+	    res = xfer_fn (p->bfd, p->the_bfd_section, myaddr,
+			   memaddr - p->addr, len);
+	    return (res != 0) ? len : 0;
+	  }
+	else if (memaddr >= p->endaddr)
+	  {
+	    /* This section ends before the transfer starts.  */
+	    continue;
+	  }
+	else 
+	  {
+	    /* This section overlaps the transfer.  Just do half.  */
+	    len = p->endaddr - memaddr;
+	    res = xfer_fn (p->bfd, p->the_bfd_section, myaddr,
+			   memaddr - p->addr, len);
+	    return (res != 0) ? len : 0;
+	  }
+      else
+	nextsectaddr = min (nextsectaddr, p->addr);
+    }
+
+  if (nextsectaddr >= memend)
+    return 0;				/* We can't help */
+  else
+    return - (nextsectaddr - memaddr);	/* Next boundary where we can help */
+}
+
+#ifdef FIXME
+#ifdef REG_STACK_SEGMENT
+/* MOVE TO BFD... */
+    /* Pyramids and AM29000s have an extra segment in the virtual address space
+       for the (control) stack of register-window frames.  The AM29000 folk
+       call it the "register stack" rather than the "memory stack".  */
+    else if (memaddr >= reg_stack_start && memaddr < reg_stack_end)
+      {
+	i = min (len, reg_stack_end - memaddr);
+	fileptr = memaddr - reg_stack_start + reg_stack_offset;
+	wanna_xfer = coredata;
+      }
+#endif				/* REG_STACK_SEGMENT */
+#endif /* FIXME */
+
+void
+print_section_info (t, abfd)
+  struct target_ops *t;
+  bfd *abfd;
+{
+  struct section_table *p;
+
+  printf_filtered ("\t`%s', ", bfd_get_filename(abfd));
+  wrap_here ("        ");
+  printf_filtered ("file type %s.\n", bfd_get_target(abfd));
+  if (abfd == exec_bfd)
+    {
+      printf_filtered ("\tEntry point: ");
+      print_address_numeric (bfd_get_start_address (abfd), 1, gdb_stdout);
+      printf_filtered ("\n");
+    }
+  for (p = t->to_sections; p < t->to_sections_end; p++)
+    {
+      /* FIXME-32x64 need a print_address_numeric with field width */
+      printf_filtered ("\t%s", local_hex_string_custom ((unsigned long) p->addr, "08l"));
+      printf_filtered (" - %s", local_hex_string_custom ((unsigned long) p->endaddr, "08l"));
+      if (info_verbose)
+	printf_filtered (" @ %s",
+			 local_hex_string_custom ((unsigned long) p->the_bfd_section->filepos, "08l"));
+      printf_filtered (" is %s", bfd_section_name (p->bfd, p->the_bfd_section));
+      if (p->bfd != abfd)
+	{
+	  printf_filtered (" in %s", bfd_get_filename (p->bfd));
+	}
+      printf_filtered ("\n");
+    }
+}
+
+static void
+exec_files_info (t)
+     struct target_ops *t;
+{
+  print_section_info (t, exec_bfd);
+
+  if (vmap)
+    {
+      struct vmap *vp;
+
+      printf_unfiltered ("\tMapping info for file `%s'.\n", vmap->name);
+      printf_unfiltered ("\t  %8.8s   %8.8s   %8.8s   %8.8s %8.8s %s\n",
+		       "tstart", "tend", "dstart", "dend", "section",
+		       "file(member)");
+
+    for (vp = vmap; vp; vp = vp->nxt)
+      printf_unfiltered ("\t0x%8.8x 0x%8.8x 0x%8.8x 0x%8.8x %s%s%s%s\n",
+			 vp->tstart, vp->tend, vp->dstart, vp->dend, vp->name,
+			 *vp->member ? "(" : "", vp->member,
+			 *vp->member ? ")" : "");
+    }
+}
+
+static void
+set_section_command (args, from_tty)
+     char *args;
+     int from_tty;
+{
+  struct section_table *p;
+  char *secname;
+  unsigned seclen;
+  unsigned long secaddr;
+  char secprint[100];
+  long offset;
+
+  if (args == 0)
+    error ("Must specify section name and its virtual address");
+
+  /* Parse out section name */
+  for (secname = args; !isspace(*args); args++) ;
+  seclen = args - secname;
+
+  /* Parse out new virtual address */
+  secaddr = parse_and_eval_address (args);
+
+  for (p = exec_ops.to_sections; p < exec_ops.to_sections_end; p++) {
+    if (!strncmp (secname, bfd_section_name (exec_bfd, p->the_bfd_section), seclen)
+	&& bfd_section_name (exec_bfd, p->the_bfd_section)[seclen] == '\0') {
+      offset = secaddr - p->addr;
+      p->addr += offset;
+      p->endaddr += offset;
+      if (from_tty)
+	exec_files_info(&exec_ops);
+      return;
+    }
+  } 
+  if (seclen >= sizeof (secprint))
+    seclen = sizeof (secprint) - 1;
+  strncpy (secprint, secname, seclen);
+  secprint[seclen] = '\0';
+  error ("Section %s not found", secprint);
+}
+
+/* If mourn is being called in all the right places, this could be say
+   `gdb internal error' (since generic_mourn calls
+   breakpoint_init_inferior).  */
+
+static int
+ignore (addr, contents)
+     CORE_ADDR addr;
+     char *contents;
+{
+  return 0;
+}
+
+/* Fill in the exec file target vector.  Very few entries need to be
+   defined.  */
+
+void
+init_exec_ops ()
+{
+  exec_ops.to_shortname = "exec";
+  exec_ops.to_longname = "Local exec file";
+  exec_ops.to_doc = "Use an executable file as a target.\n\
+Specify the filename of the executable file.";
+  exec_ops.to_open = exec_file_command;
+  exec_ops.to_close = exec_close;
+  exec_ops.to_attach = find_default_attach;
+  exec_ops.to_require_attach = find_default_require_attach;
+  exec_ops.to_require_detach = find_default_require_detach;
+  exec_ops.to_xfer_memory = xfer_memory;
+  exec_ops.to_files_info = exec_files_info;
+  exec_ops.to_insert_breakpoint = ignore;
+  exec_ops.to_remove_breakpoint = ignore;
+  exec_ops.to_create_inferior = find_default_create_inferior;
+  exec_ops.to_clone_and_follow_inferior = find_default_clone_and_follow_inferior;
+  exec_ops.to_stratum = file_stratum;
+  exec_ops.to_has_memory = 1;
+  exec_ops.to_magic = OPS_MAGIC;	
+}
+
+void
+_initialize_exec ()
+{
+  struct cmd_list_element *c;
+
+  init_exec_ops ();
+
+  if (!dbx_commands)
+    {
+      c = add_cmd ("file", class_files, file_command,
+		   "Use FILE as program to be debugged.\n\
+It is read for its symbols, for getting the contents of pure memory,\n\
+and it is the program executed when you use the `run' command.\n\
+If FILE cannot be found as specified, your execution directory path\n\
+($PATH) is searched for a command of that name.\n\
+No arg means to have no executable file and no symbols.", &cmdlist);
+      c->completer = filename_completer;
+    }
+
+  c = add_cmd ("exec-file", class_files, exec_file_command,
+	   "Use FILE as program for getting contents of pure memory.\n\
+If FILE cannot be found as specified, your execution directory path\n\
+is searched for a command of that name.\n\
+No arg means have no executable file.", &cmdlist);
+  c->completer = filename_completer;
+
+  add_com ("section", class_files, set_section_command,
+   "Change the base address of section SECTION of the exec file to ADDR.\n\
+This can be used if the exec file does not contain section addresses,\n\
+(such as in the a.out format), or when the addresses specified in the\n\
+file itself are wrong.  Each section must be changed separately.  The\n\
+``info files'' command lists all the sections and their addresses.");
+
+  add_show_from_set
+    (add_set_cmd ("write", class_support, var_boolean, (char *)&write_files,
+		  "Set writing into executable and core files.",
+		  &setlist),
+     &showlist);
+  
+  add_target (&exec_ops);
+}