text: /* Core dump and executable file functions below target vector, for GDB.
  
     Copyright (C) 1986, 1987, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997,
     1998, 1999, 2000, 2001, 2003, 2004, 2005, 2006, 2007, 2008
     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 3 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, see <http://www.gnu.org/licenses/>.  */
  
  #include "defs.h"
  #include "arch-utils.h"
  #include "gdb_string.h"
  #include <errno.h>
  #include <signal.h>
  #include <fcntl.h>
  #ifdef HAVE_SYS_FILE_H
  #include <sys/file.h>		/* needed for F_OK and friends */
  #endif
  #include "frame.h"		/* required by inferior.h */
  #include "inferior.h"
  #include "symtab.h"
  #include "command.h"
  #include "bfd.h"
  #include "target.h"
  #include "gdbcore.h"
  #include "gdbthread.h"
  #include "regcache.h"
  #include "regset.h"
  #include "symfile.h"
  #include "exec.h"
  #include "readline/readline.h"
  #include "gdb_assert.h"
  #include "exceptions.h"
  #include "solib.h"
  #include "filenames.h"
  
  
  #ifndef O_LARGEFILE
  #define O_LARGEFILE 0
  #endif
  
  /* List of all available core_fns.  On gdb startup, each core file
     register reader calls deprecated_add_core_fns() to register
     information on each core format it is prepared to read.  */
  
  static struct core_fns *core_file_fns = NULL;
  
  /* The core_fns for a core file handler that is prepared to read the core
     file currently open on core_bfd. */
  
  static struct core_fns *core_vec = NULL;
  
  /* FIXME: kettenis/20031023: Eventually this variable should
     disappear.  */
  
  struct gdbarch *core_gdbarch = NULL;
  
  static void core_files_info (struct target_ops *);
  
  static struct core_fns *sniff_core_bfd (bfd *);
  
  static int gdb_check_format (bfd *);
  
  static void core_open (char *, int);
  
  static void core_detach (char *, int);
  
  static void core_close (int);
  
  static void core_close_cleanup (void *ignore);
  
  static void get_core_registers (struct regcache *, int);
  
  static void add_to_thread_list (bfd *, asection *, void *);
  
  static int core_file_thread_alive (ptid_t tid);
  
  static void init_core_ops (void);
  
  void _initialize_corelow (void);
  
  struct target_ops core_ops;
  
  /* Link a new core_fns into the global core_file_fns list.  Called on gdb
     startup by the _initialize routine in each core file register reader, to
     register information about each format the the reader is prepared to
     handle. */
  
  void
  deprecated_add_core_fns (struct core_fns *cf)
  {
    cf->next = core_file_fns;
    core_file_fns = cf;
  }
  
  /* The default function that core file handlers can use to examine a
     core file BFD and decide whether or not to accept the job of
     reading the core file. */
  
  int
  default_core_sniffer (struct core_fns *our_fns, bfd *abfd)
  {
    int result;
  
    result = (bfd_get_flavour (abfd) == our_fns -> core_flavour);
    return (result);
  }
  
  /* Walk through the list of core functions to find a set that can
     handle the core file open on ABFD.  Default to the first one in the
     list if nothing matches.  Returns pointer to set that is
     selected. */
  
  static struct core_fns *
  sniff_core_bfd (bfd *abfd)
  {
    struct core_fns *cf;
    struct core_fns *yummy = NULL;
    int matches = 0;;
  
    /* Don't sniff if we have support for register sets in CORE_GDBARCH.  */
    if (core_gdbarch && gdbarch_regset_from_core_section_p (core_gdbarch))
      return NULL;
  
    for (cf = core_file_fns; cf != NULL; cf = cf->next)
      {
        if (cf->core_sniffer (cf, abfd))
  	{
  	  yummy = cf;
  	  matches++;
  	}
      }
    if (matches > 1)
      {
        warning (_("\"%s\": ambiguous core format, %d handlers match"),
  	       bfd_get_filename (abfd), matches);
      }
    else if (matches == 0)
      {
        warning (_("\"%s\": no core file handler recognizes format, using default"),
  	       bfd_get_filename (abfd));
      }
    if (yummy == NULL)
      {
        yummy = core_file_fns;
      }
    return (yummy);
  }
  
  /* The default is to reject every core file format we see.  Either
     BFD has to recognize it, or we have to provide a function in the
     core file handler that recognizes it. */
  
  int
  default_check_format (bfd *abfd)
  {
    return (0);
  }
  
  /* Attempt to recognize core file formats that BFD rejects. */
  
  static int
  gdb_check_format (bfd *abfd)
  {
    struct core_fns *cf;
  
    for (cf = core_file_fns; cf != NULL; cf = cf->next)
      {
        if (cf->check_format (abfd))
  	{
  	  return (1);
  	}
      }
    return (0);
  }
  
  /* Discard all vestiges of any previous core file and mark data and stack
     spaces as empty.  */
  
  static void
  core_close (int quitting)
  {
    char *name;
  
    if (core_bfd)
      {
        inferior_ptid = null_ptid;	/* Avoid confusion from thread stuff */
  
        /* Clear out solib state while the bfd is still open. See
           comments in clear_solib in solib.c. */
        clear_solib ();
  
        name = bfd_get_filename (core_bfd);
        if (!bfd_close (core_bfd))
  	warning (_("cannot close \"%s\": %s"),
  		 name, bfd_errmsg (bfd_get_error ()));
        xfree (name);
        core_bfd = NULL;
        if (core_ops.to_sections)
  	{
  	  xfree (core_ops.to_sections);
  	  core_ops.to_sections = NULL;
  	  core_ops.to_sections_end = NULL;
  	}
      }
    core_vec = NULL;
    core_gdbarch = NULL;
  }
  
  static void
  core_close_cleanup (void *ignore)
  {
    core_close (0/*ignored*/);
  }
  
  /* Look for sections whose names start with `.reg/' so that we can extract the
     list of threads in a core file.  */
  
  static void
  add_to_thread_list (bfd *abfd, asection *asect, void *reg_sect_arg)
  {
    int thread_id;
    asection *reg_sect = (asection *) reg_sect_arg;
  
    if (strncmp (bfd_section_name (abfd, asect), ".reg/", 5) != 0)
      return;
  
    thread_id = atoi (bfd_section_name (abfd, asect) + 5);
  
    add_thread (pid_to_ptid (thread_id));
  
  /* Warning, Will Robinson, looking at BFD private data! */
  
    if (reg_sect != NULL
        && asect->filepos == reg_sect->filepos)	/* Did we find .reg? */
      inferior_ptid = pid_to_ptid (thread_id);	/* Yes, make it current */
  }
  
  /* This routine opens and sets up the core file bfd.  */
  
  static void
  core_open (char *filename, int from_tty)
  {
    const char *p;
    int siggy;
    struct cleanup *old_chain;
    char *temp;
    bfd *temp_bfd;
    int ontop;
    int scratch_chan;
    int flags;
  
    target_preopen (from_tty);
    if (!filename)
      {
        if (core_bfd)
  	error (_("No core file specified.  (Use `detach' to stop debugging a core file.)"));
        else
  	error (_("No core file specified."));
      }
  
    filename = tilde_expand (filename);
    if (!IS_ABSOLUTE_PATH(filename))
      {
        temp = concat (current_directory, "/", filename, (char *)NULL);
        xfree (filename);
        filename = temp;
      }
  
    old_chain = make_cleanup (xfree, filename);
  
    flags = O_BINARY | O_LARGEFILE;
    if (write_files)
      flags |= O_RDWR;
    else
      flags |= O_RDONLY;
    scratch_chan = open (filename, flags, 0);
    if (scratch_chan < 0)
      perror_with_name (filename);
  
    temp_bfd = bfd_fopen (filename, gnutarget, 
  			write_files ? FOPEN_RUB : FOPEN_RB,
  			scratch_chan);
    if (temp_bfd == NULL)
      perror_with_name (filename);
  
    if (!bfd_check_format (temp_bfd, bfd_core) &&
        !gdb_check_format (temp_bfd))
      {
        /* Do it after the err msg */
        /* FIXME: should be checking for errors from bfd_close (for one thing,
           on error it does not free all the storage associated with the
           bfd).  */
        make_cleanup_bfd_close (temp_bfd);
        error (_("\"%s\" is not a core dump: %s"),
  	     filename, bfd_errmsg (bfd_get_error ()));
      }
  
    /* Looks semi-reasonable.  Toss the old core file and work on the new.  */
  
    discard_cleanups (old_chain);	/* Don't free filename any more */
    unpush_target (&core_ops);
    core_bfd = temp_bfd;
    old_chain = make_cleanup (core_close_cleanup, 0 /*ignore*/);
  
    /* FIXME: kettenis/20031023: This is very dangerous.  The
       CORE_GDBARCH that results from this call may very well be
       different from CURRENT_GDBARCH.  However, its methods may only
       work if it is selected as the current architecture, because they
       rely on swapped data (see gdbarch.c).  We should get rid of that
       swapped data.  */
    core_gdbarch = gdbarch_from_bfd (core_bfd);
  
    /* Find a suitable core file handler to munch on core_bfd */
    core_vec = sniff_core_bfd (core_bfd);
  
    validate_files ();
  
    /* Find the data section */
    if (build_section_table (core_bfd, &core_ops.to_sections,
  			   &core_ops.to_sections_end))
      error (_("\"%s\": Can't find sections: %s"),
  	   bfd_get_filename (core_bfd), bfd_errmsg (bfd_get_error ()));
  
    /* If we have no exec file, try to set the architecture from the
       core file.  We don't do this unconditionally since an exec file
       typically contains more information that helps us determine the
       architecture than a core file.  */
    if (!exec_bfd)
      set_gdbarch_from_file (core_bfd);
  
    ontop = !push_target (&core_ops);
    discard_cleanups (old_chain);
  
    /* This is done first, before anything has a chance to query the
       inferior for information such as symbols.  */
    post_create_inferior (&core_ops, from_tty);
  
    p = bfd_core_file_failing_command (core_bfd);
    if (p)
      printf_filtered (_("Core was generated by `%s'.\n"), p);
  
    siggy = bfd_core_file_failing_signal (core_bfd);
    if (siggy > 0)
      /* NOTE: target_signal_from_host() converts a target signal value
         into gdb's internal signal value.  Unfortunately gdb's internal
         value is called ``target_signal'' and this function got the
         name ..._from_host(). */
      printf_filtered (_("Program terminated with signal %d, %s.\n"), siggy,
  		     target_signal_to_string (target_signal_from_host (siggy)));
  
    /* Build up thread list from BFD sections. */
  
    init_thread_list ();
    bfd_map_over_sections (core_bfd, add_to_thread_list,
  			 bfd_get_section_by_name (core_bfd, ".reg"));
  
    if (ontop)
      {
        /* Fetch all registers from core file.  */
        target_fetch_registers (get_current_regcache (), -1);
  
        /* Now, set up the frame cache, and print the top of stack.  */
        reinit_frame_cache ();
        print_stack_frame (get_selected_frame (NULL), 1, SRC_AND_LOC);
      }
    else
      {
        warning (
  		"you won't be able to access this core file until you terminate\n\
  your %s; do ``info files''", target_longname);
      }
  }
  
  static void
  core_detach (char *args, int from_tty)
  {
    if (args)
      error (_("Too many arguments"));
    unpush_target (&core_ops);
    reinit_frame_cache ();
    if (from_tty)
      printf_filtered (_("No core file now.\n"));
  }
  
  
  /* Try to retrieve registers from a section in core_bfd, and supply
     them to core_vec->core_read_registers, as the register set numbered
     WHICH.
  
     If inferior_ptid is zero, do the single-threaded thing: look for a
     section named NAME.  If inferior_ptid is non-zero, do the
     multi-threaded thing: look for a section named "NAME/PID", where
     PID is the shortest ASCII decimal representation of inferior_ptid.
  
     HUMAN_NAME is a human-readable name for the kind of registers the
     NAME section contains, for use in error messages.
  
     If REQUIRED is non-zero, print an error if the core file doesn't
     have a section by the appropriate name.  Otherwise, just do nothing.  */
  
  static void
  get_core_register_section (struct regcache *regcache,
  			   char *name,
  			   int which,
  			   char *human_name,
  			   int required)
  {
    static char *section_name = NULL;
    struct bfd_section *section;
    bfd_size_type size;
    char *contents;
  
    xfree (section_name);
    if (PIDGET (inferior_ptid))
      section_name = xstrprintf ("%s/%d", name, PIDGET (inferior_ptid));
    else
      section_name = xstrdup (name);
  
    section = bfd_get_section_by_name (core_bfd, section_name);
    if (! section)
      {
        if (required)
  	warning (_("Couldn't find %s registers in core file."), human_name);
        return;
      }
  
    size = bfd_section_size (core_bfd, section);
    contents = alloca (size);
    if (! bfd_get_section_contents (core_bfd, section, contents,
  				  (file_ptr) 0, size))
      {
        warning (_("Couldn't read %s registers from `%s' section in core file."),
  	       human_name, name);
        return;
      }
  
    if (core_gdbarch && gdbarch_regset_from_core_section_p (core_gdbarch))
      {
        const struct regset *regset;
  
        regset = gdbarch_regset_from_core_section (core_gdbarch, name, size);
        if (regset == NULL)
  	{
  	  if (required)
  	    warning (_("Couldn't recognize %s registers in core file."),
  		     human_name);
  	  return;
  	}
  
        regset->supply_regset (regset, regcache, -1, contents, size);
        return;
      }
  
    gdb_assert (core_vec);
    core_vec->core_read_registers (regcache, contents, size, which,
  				 ((CORE_ADDR)
  				  bfd_section_vma (core_bfd, section)));
  }
  
  
  /* Get the registers out of a core file.  This is the machine-
     independent part.  Fetch_core_registers is the machine-dependent
     part, typically implemented in the xm-file for each architecture.  */
  
  /* We just get all the registers, so we don't use regno.  */
  
  static void
  get_core_registers (struct regcache *regcache, int regno)
  {
    int i;
  
    if (!(core_gdbarch && gdbarch_regset_from_core_section_p (core_gdbarch))
        && (core_vec == NULL || core_vec->core_read_registers == NULL))
      {
        fprintf_filtered (gdb_stderr,
  		     "Can't fetch registers from this type of core file\n");
        return;
      }
  
    get_core_register_section (regcache,
  			     ".reg", 0, "general-purpose", 1);
    get_core_register_section (regcache,
  			     ".reg2", 2, "floating-point", 0);
    get_core_register_section (regcache,
  			     ".reg-xfp", 3, "extended floating-point", 0);
    get_core_register_section (regcache,
    			     ".reg-ppc-vmx", 3, "ppc Altivec", 0);
  
    /* Supply dummy value for all registers not found in the core.  */
    for (i = 0; i < gdbarch_num_regs (get_regcache_arch (regcache)); i++)
      if (!regcache_valid_p (regcache, i))
        regcache_raw_supply (regcache, i, NULL);
  }
  
  static void
  core_files_info (struct target_ops *t)
  {
    print_section_info (t, core_bfd);
  }
  
  static LONGEST
  core_xfer_partial (struct target_ops *ops, enum target_object object,
  		   const char *annex, gdb_byte *readbuf,
  		   const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
  {
    switch (object)
      {
      case TARGET_OBJECT_MEMORY:
        if (readbuf)
  	return (*ops->deprecated_xfer_memory) (offset, readbuf,
  					       len, 0/*read*/, NULL, ops);
        if (writebuf)
  	return (*ops->deprecated_xfer_memory) (offset, (gdb_byte *) writebuf,
  					       len, 1/*write*/, NULL, ops);
        return -1;
  
      case TARGET_OBJECT_AUXV:
        if (readbuf)
  	{
  	  /* When the aux vector is stored in core file, BFD
  	     represents this with a fake section called ".auxv".  */
  
  	  struct bfd_section *section;
  	  bfd_size_type size;
  	  char *contents;
  
  	  section = bfd_get_section_by_name (core_bfd, ".auxv");
  	  if (section == NULL)
  	    return -1;
  
  	  size = bfd_section_size (core_bfd, section);
  	  if (offset >= size)
  	    return 0;
  	  size -= offset;
  	  if (size > len)
  	    size = len;
  	  if (size > 0
  	      && !bfd_get_section_contents (core_bfd, section, readbuf,
  					    (file_ptr) offset, size))
  	    {
  	      warning (_("Couldn't read NT_AUXV note in core file."));
  	      return -1;
  	    }
  
  	  return size;
  	}
        return -1;
  
      case TARGET_OBJECT_WCOOKIE:
        if (readbuf)
  	{
  	  /* When the StackGhost cookie is stored in core file, BFD
  	     represents this with a fake section called ".wcookie".  */
  
  	  struct bfd_section *section;
  	  bfd_size_type size;
  	  char *contents;
  
  	  section = bfd_get_section_by_name (core_bfd, ".wcookie");
  	  if (section == NULL)
  	    return -1;
  
  	  size = bfd_section_size (core_bfd, section);
  	  if (offset >= size)
  	    return 0;
  	  size -= offset;
  	  if (size > len)
  	    size = len;
  	  if (size > 0
  	      && !bfd_get_section_contents (core_bfd, section, readbuf,
  					    (file_ptr) offset, size))
  	    {
  	      warning (_("Couldn't read StackGhost cookie in core file."));
  	      return -1;
  	    }
  
  	  return size;
  	}
        return -1;
  
      case TARGET_OBJECT_LIBRARIES:
        if (core_gdbarch
  	  && gdbarch_core_xfer_shared_libraries_p (core_gdbarch))
  	{
  	  if (writebuf)
  	    return -1;
  	  return
  	    gdbarch_core_xfer_shared_libraries (core_gdbarch,
  						readbuf, offset, len);
  	}
        /* FALL THROUGH */
  
      default:
        if (ops->beneath != NULL)
  	return ops->beneath->to_xfer_partial (ops->beneath, object, annex,
  					      readbuf, writebuf, offset, len);
        return -1;
      }
  }
  
  
  /* 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 (struct bp_target_info *bp_tgt)
  {
    return 0;
  }
  
  
  /* Okay, let's be honest: threads gleaned from a core file aren't
     exactly lively, are they?  On the other hand, if we don't claim
     that each & every one is alive, then we don't get any of them
     to appear in an "info thread" command, which is quite a useful
     behaviour.
   */
  static int
  core_file_thread_alive (ptid_t tid)
  {
    return 1;
  }
  
  /* Ask the current architecture what it knows about this core file.
     That will be used, in turn, to pick a better architecture.  This
     wrapper could be avoided if targets got a chance to specialize
     core_ops.  */
  
  static const struct target_desc *
  core_read_description (struct target_ops *target)
  {
    if (gdbarch_core_read_description_p (current_gdbarch))
      return gdbarch_core_read_description (current_gdbarch, target, core_bfd);
  
    return NULL;
  }
  
  /* Fill in core_ops with its defined operations and properties.  */
  
  static void
  init_core_ops (void)
  {
    core_ops.to_shortname = "core";
    core_ops.to_longname = "Local core dump file";
    core_ops.to_doc =
      "Use a core file as a target.  Specify the filename of the core file.";
    core_ops.to_open = core_open;
    core_ops.to_close = core_close;
    core_ops.to_attach = find_default_attach;
    core_ops.to_detach = core_detach;
    core_ops.to_fetch_registers = get_core_registers;
    core_ops.to_xfer_partial = core_xfer_partial;
    core_ops.deprecated_xfer_memory = xfer_memory;
    core_ops.to_files_info = core_files_info;
    core_ops.to_insert_breakpoint = ignore;
    core_ops.to_remove_breakpoint = ignore;
    core_ops.to_create_inferior = find_default_create_inferior;
    core_ops.to_thread_alive = core_file_thread_alive;
    core_ops.to_read_description = core_read_description;
    core_ops.to_stratum = core_stratum;
    core_ops.to_has_memory = 1;
    core_ops.to_has_stack = 1;
    core_ops.to_has_registers = 1;
    core_ops.to_magic = OPS_MAGIC;
  }
  
  /* non-zero if we should not do the add_target call in
     _initialize_corelow; not initialized (i.e., bss) so that
     the target can initialize it (i.e., data) if appropriate.
     This needs to be set at compile time because we don't know
     for sure whether the target's initialize routine is called
     before us or after us. */
  int coreops_suppress_target;
  
  void
  _initialize_corelow (void)
  {
    init_core_ops ();
  
    if (!coreops_suppress_target)
      add_target (&core_ops);
  }
  