Fix the problems WRT overwriting a capture file. From Joerg Mayer.

[metze/wireshark/wip.git] / file.c

/* file.c
 * File I/O routines
 *
 * $Id: file.c,v 1.283 2002/07/21 16:54:22 sharpe Exp $
 *
 * Ethereal - Network traffic analyzer
 * By Gerald Combs <gerald@ethereal.com>
 * Copyright 1998 Gerald Combs
 * 
 * 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.
 */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <gtk/gtk.h>

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include <time.h>

#ifdef HAVE_IO_H
#include <io.h>
#endif

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <signal.h>

#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif

#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif

#ifdef NEED_SNPRINTF_H
# include "snprintf.h"
#endif

#ifdef NEED_STRERROR_H
#include "strerror.h"
#endif

#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif

#ifdef HAVE_NETINET_IN_H
# include <netinet/in.h>
#endif

#include <epan/epan.h>
#include <epan/filesystem.h>

#include "gtk/main.h"
#include "color.h"
#include "gtk/color_utils.h"
#include "column.h"
#include <epan/packet.h>
#include "print.h"
#include "file.h"
#include "menu.h"
#include "util.h"
#include "simple_dialog.h"
#include "progress_dlg.h"
#include "ui_util.h"
#include "statusbar.h"
#include "prefs.h"
#include "gtk/proto_draw.h"
#include "gtk/packet_win.h"
#include <epan/dfilter/dfilter.h>
#include <epan/conversation.h>
#include "globals.h"
#include "gtk/colors.h"
#include <epan/epan_dissect.h>

extern GtkWidget *packet_list, *byte_nb_ptr, *tree_view;

#ifdef HAVE_LIBPCAP
gboolean auto_scroll_live;
#endif

static guint32 firstsec, firstusec;
static guint32 prevsec, prevusec;

static void read_packet(capture_file *cf, long offset);

static void rescan_packets(capture_file *cf, const char *action,
        gboolean refilter, gboolean redissect);

static void set_selected_row(int row);

static void freeze_clist(capture_file *cf);
static void thaw_clist(capture_file *cf);

static char *file_rename_error_message(int err);
static char *file_close_error_message(int err);
static gboolean copy_binary_file(char *from_filename, char *to_filename);

/* Update the progress bar this many times when reading a file. */
#define N_PROGBAR_UPDATES       100

/* Number of "frame_data" structures per memory chunk.
   XXX - is this the right number? */
#define FRAME_DATA_CHUNK_SIZE   1024

int
open_cap_file(char *fname, gboolean is_tempfile, capture_file *cf)
{
  wtap       *wth;
  int         err;
  int         fd;
  struct stat cf_stat;

  wth = wtap_open_offline(fname, &err, TRUE);
  if (wth == NULL)
    goto fail;

  /* Find the size of the file. */
  fd = wtap_fd(wth);
  if (fstat(fd, &cf_stat) < 0) {
    err = errno;
    wtap_close(wth);
    goto fail;
  }

  /* The open succeeded.  Close whatever capture file we had open,
     and fill in the information for this file. */
  close_cap_file(cf);

  /* Initialize all data structures used for dissection. */
  init_dissection();

  /* We're about to start reading the file. */
  cf->state = FILE_READ_IN_PROGRESS;

  cf->wth = wth;
  cf->filed = fd;
  cf->f_len = cf_stat.st_size;

  /* Set the file name because we need it to set the follow stream filter.
     XXX - is that still true?  We need it for other reasons, though,
     in any case. */
  cf->filename = g_strdup(fname);

  /* Indicate whether it's a permanent or temporary file. */
  cf->is_tempfile = is_tempfile;

  /* If it's a temporary capture buffer file, mark it as not saved. */
  cf->user_saved = !is_tempfile;

  cf->cd_t      = wtap_file_type(cf->wth);
  cf->count     = 0;
  cf->marked_count = 0;
  cf->drops_known = FALSE;
  cf->drops     = 0;
  cf->esec      = 0;
  cf->eusec     = 0;
  cf->snap      = wtap_snapshot_length(cf->wth);
  if (cf->snap == 0) {
    /* Snapshot length not known. */
    cf->has_snap = FALSE;
    cf->snap = WTAP_MAX_PACKET_SIZE;
  } else
    cf->has_snap = TRUE;
  cf->progbar_quantum = 0;
  cf->progbar_nextstep = 0;
  firstsec = 0, firstusec = 0;
  prevsec = 0, prevusec = 0;
 
  cf->plist_chunk = g_mem_chunk_new("frame_data_chunk",
        sizeof(frame_data),
        FRAME_DATA_CHUNK_SIZE * sizeof(frame_data),
        G_ALLOC_AND_FREE);
  g_assert(cf->plist_chunk);

  return (0);

fail:
  simple_dialog(ESD_TYPE_CRIT, NULL,
                        file_open_error_message(err, FALSE, 0), fname);
  return (err);
}

/* Reset everything to a pristine state */
void
close_cap_file(capture_file *cf)
{
  /* Die if we're in the middle of reading a file. */
  g_assert(cf->state != FILE_READ_IN_PROGRESS);

  /* Destroy all popup packet windows, as they refer to packets in the
     capture file we're closing. */
  destroy_packet_wins();

  if (cf->wth) {
    wtap_close(cf->wth);
    cf->wth = NULL;
  }
  /* We have no file open... */
  if (cf->filename != NULL) {
    /* If it's a temporary file, remove it. */
    if (cf->is_tempfile)
      unlink(cf->filename);
    g_free(cf->filename);
    cf->filename = NULL;
  }
  /* ...which means we have nothing to save. */
  cf->user_saved = FALSE;

  if (cf->plist_chunk != NULL) {
    g_mem_chunk_destroy(cf->plist_chunk);
    cf->plist_chunk = NULL;
  }
  if (cf->rfcode != NULL) {
    dfilter_free(cf->rfcode);
    cf->rfcode = NULL;
  }
  cf->plist = NULL;
  cf->plist_end = NULL;
  unselect_packet(cf);  /* nothing to select */
  cf->first_displayed = NULL;
  cf->last_displayed = NULL;

  /* Clear the packet list. */
  gtk_clist_freeze(GTK_CLIST(packet_list));
  gtk_clist_clear(GTK_CLIST(packet_list));
  gtk_clist_thaw(GTK_CLIST(packet_list));

  /* Clear any file-related status bar messages.
     XXX - should be "clear *ALL* file-related status bar messages;
     will there ever be more than one on the stack? */
  statusbar_pop_file_msg();

  /* Restore the standard title bar message. */
  set_main_window_name("The Ethereal Network Analyzer");

  /* Disable all menu items that make sense only if you have a capture. */
  set_menus_for_capture_file(FALSE);
  set_menus_for_unsaved_capture_file(FALSE);
  set_menus_for_captured_packets(FALSE);
  set_menus_for_selected_packet(FALSE);
  set_menus_for_capture_in_progress(FALSE);
  set_menus_for_selected_tree_row(FALSE);

  /* We have no file open. */
  cf->state = FILE_CLOSED;
}

/* Set the file name in the status line, in the name for the main window,
   and in the name for the main window's icon. */
static void
set_display_filename(capture_file *cf)
{
  gchar  *name_ptr;
  size_t  msg_len;
  static const gchar done_fmt_nodrops[] = " File: %s";
  static const gchar done_fmt_drops[] = " File: %s  Drops: %u";
  gchar  *done_msg;
  gchar  *win_name_fmt = "%s - Ethereal";
  gchar  *win_name;

  if (!cf->is_tempfile) {
    /* Get the last component of the file name, and put that in the
       status bar. */
    name_ptr = get_basename(cf->filename);
  } else {
    /* The file we read is a temporary file from a live capture;
       we don't mention its name in the status bar. */
    name_ptr = "<capture>";
  }

  if (cf->drops_known) {
    msg_len = strlen(name_ptr) + strlen(done_fmt_drops) + 64;
    done_msg = g_malloc(msg_len);
    snprintf(done_msg, msg_len, done_fmt_drops, name_ptr, cf->drops);
  } else {
    msg_len = strlen(name_ptr) + strlen(done_fmt_nodrops);
    done_msg = g_malloc(msg_len);
    snprintf(done_msg, msg_len, done_fmt_nodrops, name_ptr);
  }
  statusbar_push_file_msg(done_msg);
  g_free(done_msg);

  msg_len = strlen(name_ptr) + strlen(win_name_fmt) + 1;
  win_name = g_malloc(msg_len);
  snprintf(win_name, msg_len, win_name_fmt, name_ptr);
  set_main_window_name(win_name);
  g_free(win_name);
}

read_status_t
read_cap_file(capture_file *cf, int *err)
{
  gchar      *name_ptr, *load_msg, *load_fmt = " Loading: %s...";
  size_t      msg_len;
  char       *errmsg;
  char        errmsg_errno[1024+1];
  gchar       err_str[2048+1];
  long        data_offset;
  progdlg_t  *progbar;
  gboolean    stop_flag;
  int         file_pos;
  float       prog_val;
  int         fd;
  struct stat cf_stat;

  name_ptr = get_basename(cf->filename);

  msg_len = strlen(name_ptr) + strlen(load_fmt) + 2;
  load_msg = g_malloc(msg_len);
  snprintf(load_msg, msg_len, load_fmt, name_ptr);
  statusbar_push_file_msg(load_msg);

  /* Update the progress bar when it gets to this value. */
  cf->progbar_nextstep = 0;
  /* When we reach the value that triggers a progress bar update,
     bump that value by this amount. */
  cf->progbar_quantum = cf->f_len/N_PROGBAR_UPDATES;

#ifndef O_BINARY
#define O_BINARY        0
#endif

  freeze_clist(cf);

  stop_flag = FALSE;
  progbar = create_progress_dlg(load_msg, "Stop", &stop_flag);
  g_free(load_msg);

  while ((wtap_read(cf->wth, err, &data_offset))) {
    /* Update the progress bar, but do it only N_PROGBAR_UPDATES times;
       when we update it, we have to run the GTK+ main loop to get it
       to repaint what's pending, and doing so may involve an "ioctl()"
       to see if there's any pending input from an X server, and doing
       that for every packet can be costly, especially on a big file. */
    if (data_offset >= cf->progbar_nextstep) {
        file_pos = lseek(cf->filed, 0, SEEK_CUR);
        prog_val = (gfloat) file_pos / (gfloat) cf->f_len;
        if (prog_val > 1.0) {
          /* The file probably grew while we were reading it.
             Update "cf->f_len", and try again. */
          fd = wtap_fd(cf->wth);
          if (fstat(fd, &cf_stat) >= 0) {
            cf->f_len = cf_stat.st_size;
            prog_val = (gfloat) file_pos / (gfloat) cf->f_len;
          }
          /* If it's still > 1, either the "fstat()" failed (in which
             case there's not much we can do about it), or the file
             *shrank* (in which case there's not much we can do about
             it); just clip the progress value at 1.0. */
          if (prog_val > 1.0)
            prog_val = 1.0;
        }
        update_progress_dlg(progbar, prog_val);
        cf->progbar_nextstep += cf->progbar_quantum;
    }

    if (stop_flag) {
      /* Well, the user decided to abort the read.  Destroy the progress
         bar, close the capture file, and return READ_ABORTED so our caller
         can do whatever is appropriate when that happens. */
      destroy_progress_dlg(progbar);
      cf->state = FILE_READ_ABORTED;    /* so that we're allowed to close it */
      gtk_clist_thaw(GTK_CLIST(packet_list));   /* undo our freeze */
      close_cap_file(cf);
      return (READ_ABORTED);
    }
    read_packet(cf, data_offset);
  }

  /* We're done reading the file; destroy the progress bar. */
  destroy_progress_dlg(progbar);

  /* We're done reading sequentially through the file. */
  cf->state = FILE_READ_DONE;

  /* Close the sequential I/O side, to free up memory it requires. */
  wtap_sequential_close(cf->wth);

  /* Allow the protocol dissectors to free up memory that they
   * don't need after the sequential run-through of the packets. */
  postseq_cleanup_all_protocols();

  /* Set the file encapsulation type now; we don't know what it is until
     we've looked at all the packets, as we don't know until then whether
     there's more than one type (and thus whether it's
     WTAP_ENCAP_PER_PACKET). */
  cf->lnk_t = wtap_file_encap(cf->wth);

  cf->current_frame = cf->first_displayed;
  thaw_clist(cf);

  statusbar_pop_file_msg();
  set_display_filename(cf);

  /* Enable menu items that make sense if you have a capture file you've
     finished reading. */
  set_menus_for_capture_file(TRUE);
  set_menus_for_unsaved_capture_file(!cf->user_saved);

  /* Enable menu items that make sense if you have some captured packets. */
  set_menus_for_captured_packets(TRUE);

  /* If we have any displayed packets to select, select the first of those
     packets by making the first row the selected row. */
  if (cf->first_displayed != NULL)
    gtk_signal_emit_by_name(GTK_OBJECT(packet_list), "select_row", 0);

  if (*err != 0) {
    /* Put up a message box noting that the read failed somewhere along
       the line.  Don't throw out the stuff we managed to read, though,
       if any. */
    switch (*err) {

    case WTAP_ERR_UNSUPPORTED_ENCAP:
      errmsg = "The capture file is for a network type that Ethereal doesn't support.";
      break;

    case WTAP_ERR_CANT_READ:
      errmsg = "An attempt to read from the file failed for"
               " some unknown reason.";
      break;

    case WTAP_ERR_SHORT_READ:
      errmsg = "The capture file appears to have been cut short"
               " in the middle of a packet.";
      break;

    case WTAP_ERR_BAD_RECORD:
      errmsg = "The capture file appears to be damaged or corrupt.";
      break;

    default:
      snprintf(errmsg_errno, sizeof(errmsg_errno),
               "An error occurred while reading the"
               " capture file: %s.", wtap_strerror(*err));
      errmsg = errmsg_errno;
      break;
    }
    snprintf(err_str, sizeof err_str, errmsg);
    simple_dialog(ESD_TYPE_CRIT, NULL, err_str);
    return (READ_ERROR);
  } else
    return (READ_SUCCESS);
}

#ifdef HAVE_LIBPCAP
int
start_tail_cap_file(char *fname, gboolean is_tempfile, capture_file *cf)
{
  int     err;
  int     i;

  err = open_cap_file(fname, is_tempfile, cf);
  if (err == 0) {
    /* Disable menu items that make no sense if you're currently running
       a capture. */
    set_menus_for_capture_in_progress(TRUE);

    /* Enable menu items that make sense if you have some captured
       packets (yes, I know, we don't have any *yet*). */
    set_menus_for_captured_packets(TRUE);

    for (i = 0; i < cf->cinfo.num_cols; i++) {
      if (get_column_resize_type(cf->cinfo.col_fmt[i]) == RESIZE_LIVE)
        gtk_clist_set_column_auto_resize(GTK_CLIST(packet_list), i, TRUE);
      else {
        gtk_clist_set_column_auto_resize(GTK_CLIST(packet_list), i, FALSE);
        gtk_clist_set_column_width(GTK_CLIST(packet_list), i,
                                cf->cinfo.col_width[i]);
        gtk_clist_set_column_resizeable(GTK_CLIST(packet_list), i, TRUE);
      }
    }

    statusbar_push_file_msg(" <live capture in progress>");
  }
  return err;
}

read_status_t
continue_tail_cap_file(capture_file *cf, int to_read, int *err)
{
  long data_offset = 0;

  gtk_clist_freeze(GTK_CLIST(packet_list));

  while (to_read != 0 && (wtap_read(cf->wth, err, &data_offset))) {
    if (cf->state == FILE_READ_ABORTED) {
      /* Well, the user decided to exit Ethereal.  Break out of the
         loop, and let the code below (which is called even if there
         aren't any packets left to read) exit. */
      break;
    }
    read_packet(cf, data_offset);
    to_read--;
  }

  gtk_clist_thaw(GTK_CLIST(packet_list));

  /* XXX - this cheats and looks inside the packet list to find the final
     row number. */
  if (auto_scroll_live && cf->plist_end != NULL)
    gtk_clist_moveto(GTK_CLIST(packet_list), 
                       GTK_CLIST(packet_list)->rows - 1, -1, 1.0, 1.0);

  if (cf->state == FILE_READ_ABORTED) {
    /* Well, the user decided to exit Ethereal.  Return READ_ABORTED
       so that our caller can kill off the capture child process;
       this will cause an EOF on the pipe from the child, so
       "finish_tail_cap_file()" will be called, and it will clean up
       and exit. */
    return READ_ABORTED;
  } else if (*err != 0) {
    /* We got an error reading the capture file.
       XXX - pop up a dialog box? */
    return (READ_ERROR);
  } else
    return (READ_SUCCESS);
}

read_status_t
finish_tail_cap_file(capture_file *cf, int *err)
{
  long data_offset;

  gtk_clist_freeze(GTK_CLIST(packet_list));

  while ((wtap_read(cf->wth, err, &data_offset))) {
    if (cf->state == FILE_READ_ABORTED) {
      /* Well, the user decided to abort the read.  Break out of the
         loop, and let the code below (which is called even if there
         aren't any packets left to read) exit. */
      break;
    }
    read_packet(cf, data_offset);
  }

  if (cf->state == FILE_READ_ABORTED) {
    /* Well, the user decided to abort the read.  We're only called
       when the child capture process closes the pipe to us (meaning
       it's probably exited), so we can just close the capture
       file; we return READ_ABORTED so our caller can do whatever
       is appropriate when that happens. */
    close_cap_file(cf);
    return READ_ABORTED;
  }

  thaw_clist(cf);
  if (auto_scroll_live && cf->plist_end != NULL)
    /* XXX - this cheats and looks inside the packet list to find the final
       row number. */
    gtk_clist_moveto(GTK_CLIST(packet_list), 
                       GTK_CLIST(packet_list)->rows - 1, -1, 1.0, 1.0);

  /* We're done reading sequentially through the file. */
  cf->state = FILE_READ_DONE;

  /* We're done reading sequentially through the file; close the
     sequential I/O side, to free up memory it requires. */
  wtap_sequential_close(cf->wth);

  /* Allow the protocol dissectors to free up memory that they
   * don't need after the sequential run-through of the packets. */
  postseq_cleanup_all_protocols();

  /* Set the file encapsulation type now; we don't know what it is until
     we've looked at all the packets, as we don't know until then whether
     there's more than one type (and thus whether it's
     WTAP_ENCAP_PER_PACKET). */
  cf->lnk_t = wtap_file_encap(cf->wth);

  /* Pop the "<live capture in progress>" message off the status bar. */
  statusbar_pop_file_msg();

  set_display_filename(cf);

  /* Enable menu items that make sense if you're not currently running
     a capture. */
  set_menus_for_capture_in_progress(FALSE);

  /* Enable menu items that make sense if you have a capture file
     you've finished reading. */
  set_menus_for_capture_file(TRUE);
  set_menus_for_unsaved_capture_file(!cf->user_saved);

  if (*err != 0) {
    /* We got an error reading the capture file.
       XXX - pop up a dialog box? */
    return (READ_ERROR);
  } else
    return (READ_SUCCESS);
}
#endif /* HAVE_LIBPCAP */

typedef struct {
  color_filter_t *colorf;
  epan_dissect_t *edt;
} apply_color_filter_args;

/*
 * If no color filter has been applied, apply this one.
 * (The "if no color filter has been applied" is to handle the case where
 * more than one color filter matches the packet.)
 */
static void
apply_color_filter(gpointer filter_arg, gpointer argp)
{
  color_filter_t *colorf = filter_arg;
  apply_color_filter_args *args = argp;

  if (colorf->c_colorfilter != NULL && args->colorf == NULL) {
    if (dfilter_apply_edt(colorf->c_colorfilter, args->edt))
      args->colorf = colorf;
  }
}

static int
add_packet_to_packet_list(frame_data *fdata, capture_file *cf,
        union wtap_pseudo_header *pseudo_header, const u_char *buf,
        gboolean refilter)
{
  apply_color_filter_args args;
  gint          row;
  gboolean      create_proto_tree = FALSE;
  epan_dissect_t *edt;
  GdkColor      fg, bg;

  /* We don't yet have a color filter to apply. */
  args.colorf = NULL;

  /* If we don't have the time stamp of the first packet in the
     capture, it's because this is the first packet.  Save the time
     stamp of this packet as the time stamp of the first packet. */
  if (!firstsec && !firstusec) {
    firstsec  = fdata->abs_secs;
    firstusec = fdata->abs_usecs;
  }

  /* If either

        we have a display filter and are re-applying it;

        we have a list of color filters;

     allocate a protocol tree root node, so that we'll construct
     a protocol tree against which a filter expression can be
     evaluated. */
  if ((cf->dfcode != NULL && refilter) || filter_list != NULL)
          create_proto_tree = TRUE;

  /* Dissect the frame. */
  edt = epan_dissect_new(create_proto_tree, FALSE);

  if (cf->dfcode != NULL && refilter) {
      epan_dissect_prime_dfilter(edt, cf->dfcode);
  }
  if (filter_list) {
      filter_list_prime_edt(edt);
  }
  epan_dissect_run(edt, pseudo_header, buf, fdata, &cf->cinfo);


  /* If we have a display filter, apply it if we're refiltering, otherwise
     leave the "passed_dfilter" flag alone.

     If we don't have a display filter, set "passed_dfilter" to 1. */
  if (cf->dfcode != NULL) {
    if (refilter) {
      if (cf->dfcode != NULL)
        fdata->flags.passed_dfilter = dfilter_apply_edt(cf->dfcode, edt) ? 1 : 0;
      else
        fdata->flags.passed_dfilter = 1;
    }
  } else
    fdata->flags.passed_dfilter = 1;

  /* If we have color filters, and the frame is to be displayed, apply
     the color filters. */
  if (fdata->flags.passed_dfilter) {
    if (filter_list != NULL) {
      args.edt = edt;
      g_slist_foreach(filter_list, apply_color_filter, &args);
    }
  }


  if (fdata->flags.passed_dfilter) {
    /* This frame passed the display filter, so add it to the clist. */

    /* If we don't have the time stamp of the previous displayed packet,
       it's because this is the first displayed packet.  Save the time
       stamp of this packet as the time stamp of the previous displayed
       packet. */
    if (!prevsec && !prevusec) {
      prevsec  = fdata->abs_secs;
      prevusec = fdata->abs_usecs;
    }

    /* Get the time elapsed between the first packet and this packet. */
    compute_timestamp_diff(&fdata->rel_secs, &fdata->rel_usecs,
                fdata->abs_secs, fdata->abs_usecs, firstsec, firstusec);

    /* If it's greater than the current elapsed time, set the elapsed time
       to it (we check for "greater than" so as not to be confused by
       time moving backwards). */
    if ((gint32)cf->esec < fdata->rel_secs
        || ((gint32)cf->esec == fdata->rel_secs && (gint32)cf->eusec < fdata->rel_usecs)) {
      cf->esec = fdata->rel_secs;
      cf->eusec = fdata->rel_usecs;
    }
  
    /* Get the time elapsed between the previous displayed packet and
       this packet. */
    compute_timestamp_diff(&fdata->del_secs, &fdata->del_usecs,
                fdata->abs_secs, fdata->abs_usecs, prevsec, prevusec);
    prevsec = fdata->abs_secs;
    prevusec = fdata->abs_usecs;

    epan_dissect_fill_in_columns(edt);

    /* If we haven't yet seen the first frame, this is it.

       XXX - we must do this before we add the row to the display,
       as, if the display's GtkCList's selection mode is
       GTK_SELECTION_BROWSE, when the first entry is added to it,
       "select_packet()" will be called, and it will fetch the row
       data for the 0th row, and will get a null pointer rather than
       "fdata", as "gtk_clist_append()" won't yet have returned and
       thus "gtk_clist_set_row_data()" won't yet have been called.

       We thus need to leave behind bread crumbs so that
       "select_packet()" can find this frame.  See the comment
       in "select_packet()". */
    if (cf->first_displayed == NULL)
      cf->first_displayed = fdata;

    /* This is the last frame we've seen so far. */
    cf->last_displayed = fdata;

    row = gtk_clist_append(GTK_CLIST(packet_list), cf->cinfo.col_data);
    gtk_clist_set_row_data(GTK_CLIST(packet_list), row, fdata);

    if (fdata->flags.marked) {
        color_t_to_gdkcolor(&bg, &prefs.gui_marked_bg);
        color_t_to_gdkcolor(&fg, &prefs.gui_marked_fg);
    } else if (filter_list != NULL && (args.colorf != NULL)) {
        bg = args.colorf->bg_color;
        fg = args.colorf->fg_color;
    } else {
        bg = WHITE;
        fg = BLACK;
    }
    gtk_clist_set_background(GTK_CLIST(packet_list), row, &bg);
    gtk_clist_set_foreground(GTK_CLIST(packet_list), row, &fg);
  } else {
    /* This frame didn't pass the display filter, so it's not being added
       to the clist, and thus has no row. */
    row = -1;
  }
  epan_dissect_free(edt);
  return row;
}

static void
read_packet(capture_file *cf, long offset)
{
  const struct wtap_pkthdr *phdr = wtap_phdr(cf->wth);
  union wtap_pseudo_header *pseudo_header = wtap_pseudoheader(cf->wth);
  const u_char *buf = wtap_buf_ptr(cf->wth);
  frame_data   *fdata;
  int           passed;
  frame_data   *plist_end;
  epan_dissect_t *edt;

  /* Allocate the next list entry, and add it to the list. */
  fdata = g_mem_chunk_alloc(cf->plist_chunk);

  fdata->next = NULL;
  fdata->prev = NULL;
  fdata->pfd  = NULL;
  fdata->pkt_len  = phdr->len;
  fdata->cap_len  = phdr->caplen;
  fdata->file_off = offset;
  fdata->lnk_t = phdr->pkt_encap;
  fdata->abs_secs  = phdr->ts.tv_sec;
  fdata->abs_usecs = phdr->ts.tv_usec;
  fdata->flags.encoding = CHAR_ASCII;
  fdata->flags.visited = 0;
  fdata->flags.marked = 0;

  passed = TRUE;
  if (cf->rfcode) {
    edt = epan_dissect_new(TRUE, FALSE);
    epan_dissect_prime_dfilter(edt, cf->rfcode);
    epan_dissect_run(edt, pseudo_header, buf, fdata, NULL);
    passed = dfilter_apply_edt(cf->rfcode, edt);
    epan_dissect_free(edt);
  }   
  if (passed) {
    plist_end = cf->plist_end;
    fdata->prev = plist_end;
    if (plist_end != NULL)
      plist_end->next = fdata;
    else
      cf->plist = fdata;
    cf->plist_end = fdata;

    cf->count++;
    fdata->num = cf->count;
    add_packet_to_packet_list(fdata, cf, pseudo_header, buf, TRUE);
  } else {
    /* XXX - if we didn't have read filters, or if we could avoid
       allocating the "frame_data" structure until we knew whether
       the frame passed the read filter, we could use a G_ALLOC_ONLY
       memory chunk...

       ...but, at least in one test I did, where I just made the chunk
       a G_ALLOC_ONLY chunk and read in a huge capture file, it didn't
       seem to save a noticeable amount of time or space. */
    g_mem_chunk_free(cf->plist_chunk, fdata);
  }
}

int
filter_packets(capture_file *cf, gchar *dftext)
{
  dfilter_t *dfcode;

  if (dftext == NULL) {
    /* The new filter is an empty filter (i.e., display all packets). */
    dfcode = NULL;
  } else {
    /*
     * We have a filter; make a copy of it (as we'll be saving it),
     * and try to compile it.
     */
    dftext = g_strdup(dftext);
    if (!dfilter_compile(dftext, &dfcode)) {
      /* The attempt failed; report an error. */
      simple_dialog(ESD_TYPE_CRIT, NULL, dfilter_error_msg);
      return 0;
    }

    /* Was it empty? */
    if (dfcode == NULL) {
      /* Yes - free the filter text, and set it to null. */
      g_free(dftext);
      dftext = NULL;
    }
  }

  /* We have a valid filter.  Replace the current filter. */
  if (cf->dfilter != NULL)
    g_free(cf->dfilter);
  cf->dfilter = dftext;
  if (cf->dfcode != NULL)
    dfilter_free(cf->dfcode);
  cf->dfcode = dfcode;

  /* Now rescan the packet list, applying the new filter, but not
     throwing away information constructed on a previous pass. */
  rescan_packets(cf, "Filtering", TRUE, FALSE);
  return 1;
}

void
colorize_packets(capture_file *cf)
{
  rescan_packets(cf, "Colorizing", FALSE, FALSE);
}

void
redissect_packets(capture_file *cf)
{
  rescan_packets(cf, "Reprocessing", TRUE, TRUE);
}

/* Rescan the list of packets, reconstructing the CList.

   "action" describes why we're doing this; it's used in the progress
   dialog box.

   "refilter" is TRUE if we need to re-evaluate the filter expression.

   "redissect" is TRUE if we need to make the dissectors reconstruct
   any state information they have (because a preference that affects
   some dissector has changed, meaning some dissector might construct
   its state differently from the way it was constructed the last time). */
static void
rescan_packets(capture_file *cf, const char *action, gboolean refilter,
                gboolean redissect)
{
  frame_data *fdata;
  progdlg_t *progbar;
  gboolean stop_flag;
  guint32 progbar_quantum;
  guint32 progbar_nextstep;
  unsigned int count;
  int err;
  frame_data *selected_frame;
  int selected_row;
  int row;

  /* Which frame, if any, is the currently selected frame?
     XXX - should the selected frame or the focus frame be the "current"
     frame, that frame being the one from which "Find Frame" searches
     start? */
  selected_frame = cf->current_frame;

  /* We don't yet know what row that frame will be on, if any, after we
     rebuild the clist, however. */
  selected_row = -1;

  if (redissect) {
    /* We need to re-initialize all the state information that protocols
       keep, because some preference that controls a dissector has changed,
       which might cause the state information to be constructed differently
       by that dissector. */

    /* Initialize all data structures used for dissection. */
    init_dissection();
  }

  /* Freeze the packet list while we redo it, so we don't get any
     screen updates while it happens. */
  gtk_clist_freeze(GTK_CLIST(packet_list));

  /* Clear it out. */
  gtk_clist_clear(GTK_CLIST(packet_list));

  /* We don't yet know which will be the first and last frames displayed. */
  cf->first_displayed = NULL;
  cf->last_displayed = NULL;

  /* Iterate through the list of frames.  Call a routine for each frame
     to check whether it should be displayed and, if so, add it to
     the display list. */
  firstsec = 0;
  firstusec = 0;
  prevsec = 0;
  prevusec = 0;

  /* Update the progress bar when it gets to this value. */
  progbar_nextstep = 0;
  /* When we reach the value that triggers a progress bar update,
     bump that value by this amount. */
  progbar_quantum = cf->count/N_PROGBAR_UPDATES;
  /* Count of packets at which we've looked. */
  count = 0;

  stop_flag = FALSE;
  progbar = create_progress_dlg(action, "Stop", &stop_flag);

  for (fdata = cf->plist; fdata != NULL; fdata = fdata->next) {
    /* Update the progress bar, but do it only N_PROGBAR_UPDATES times;
       when we update it, we have to run the GTK+ main loop to get it
       to repaint what's pending, and doing so may involve an "ioctl()"
       to see if there's any pending input from an X server, and doing
       that for every packet can be costly, especially on a big file. */
    if (count >= progbar_nextstep) {
      /* let's not divide by zero. I should never be started
       * with count == 0, so let's assert that
       */
      g_assert(cf->count > 0);

      update_progress_dlg(progbar, (gfloat) count / cf->count);

      progbar_nextstep += progbar_quantum;
    }

    if (stop_flag) {
      /* Well, the user decided to abort the filtering.  Just stop.

         XXX - go back to the previous filter?  Users probably just
         want not to wait for a filtering operation to finish;
         unless we cancel by having no filter, reverting to the
         previous filter will probably be even more expensive than
         continuing the filtering, as it involves going back to the
         beginning and filtering, and even with no filter we currently
         have to re-generate the entire clist, which is also expensive.

         I'm not sure what Network Monitor does, but it doesn't appear
         to give you an unfiltered display if you cancel. */
      break;
    }

    count++;

    if (redissect) {
      /* Since all state for the frame was destroyed, mark the frame
       * as not visited, free the GSList referring to the state
       * data (the per-frame data itself was freed by
       * "init_dissection()"), and null out the GSList pointer. */
      fdata->flags.visited = 0;
      if (fdata->pfd) {
        g_slist_free(fdata->pfd);
        fdata->pfd = NULL;
      }
    }

    /* XXX - do something with "err" */
    wtap_seek_read (cf->wth, fdata->file_off, &cf->pseudo_header,
        cf->pd, fdata->cap_len, &err);

    row = add_packet_to_packet_list(fdata, cf, &cf->pseudo_header, cf->pd,
                                        refilter);
    if (fdata == selected_frame)
      selected_row = row;
  }
 
  if (redissect) {
    /* Clear out what remains of the visited flags and per-frame data
       pointers.

       XXX - that may cause various forms of bogosity when dissecting
       these frames, as they won't have been seen by this sequential
       pass, but the only alternative I see is to keep scanning them
       even though the user requested that the scan stop, and that
       would leave the user stuck with an Ethereal grinding on
       until it finishes.  Should we just stick them with that? */
    for (; fdata != NULL; fdata = fdata->next) {
      fdata->flags.visited = 0;
      if (fdata->pfd) {
        g_slist_free(fdata->pfd);
        fdata->pfd = NULL;
      }
    }
  }

  /* We're done filtering the packets; destroy the progress bar. */
  destroy_progress_dlg(progbar);

  /* Unfreeze the packet list. */
  gtk_clist_thaw(GTK_CLIST(packet_list));

  if (selected_row != -1) {
    /* The frame that was selected passed the filter; select it, make it
       the focus row, and make it visible. */
    set_selected_row(selected_row);
    finfo_selected = NULL;
  } else {
    /* The selected frame didn't pass the filter; make the first frame
       the current frame, and leave it unselected. */
    unselect_packet(cf);
    cf->current_frame = cf->first_displayed;
  }
}

int
print_packets(capture_file *cf, print_args_t *print_args)
{
  int         i;
  frame_data *fdata;
  progdlg_t  *progbar;
  gboolean    stop_flag;
  guint32     progbar_quantum;
  guint32     progbar_nextstep;
  guint32     count;
  int         err;
  gint       *col_widths = NULL;
  gint        data_width;
  gboolean    print_separator;
  char       *line_buf = NULL;
  int         line_buf_len = 256;
  char        *cp;
  int         column_len;
  int         line_len;
  epan_dissect_t *edt = NULL;

  cf->print_fh = open_print_dest(print_args->to_file, print_args->dest);
  if (cf->print_fh == NULL)
    return FALSE;       /* attempt to open destination failed */

  print_preamble(cf->print_fh, print_args->format);

  if (print_args->print_summary) {
    /* We're printing packet summaries.  Allocate the line buffer at
       its initial length. */
    line_buf = g_malloc(line_buf_len + 1);

    /* Find the widths for each of the columns - maximum of the
       width of the title and the width of the data - and print
       the column titles. */
    col_widths = (gint *) g_malloc(sizeof(gint) * cf->cinfo.num_cols);
    cp = &line_buf[0];
    line_len = 0;
    for (i = 0; i < cf->cinfo.num_cols; i++) {
      /* Don't pad the last column. */
      if (i == cf->cinfo.num_cols - 1)
        col_widths[i] = 0;
      else {
        col_widths[i] = strlen(cf->cinfo.col_title[i]);
        data_width = get_column_char_width(get_column_format(i));
        if (data_width > col_widths[i])
          col_widths[i] = data_width;
      }

      /* Find the length of the string for this column. */
      column_len = strlen(cf->cinfo.col_title[i]);
      if (col_widths[i] > column_len)
        column_len = col_widths[i];

      /* Make sure there's room in the line buffer for the column; if not,
         double its length. */
      line_len += column_len + 1;       /* "+1" for space */
      if (line_len > line_buf_len) {
        line_buf_len *= 2;
        line_buf = g_realloc(line_buf, line_buf_len + 1);
      }

      /* Right-justify the packet number column. */
      if (cf->cinfo.col_fmt[i] == COL_NUMBER)
        sprintf(cp, "%*s", col_widths[i], cf->cinfo.col_title[i]);
      else
        sprintf(cp, "%-*s", col_widths[i], cf->cinfo.col_title[i]);
      cp += column_len;
      if (i != cf->cinfo.num_cols - 1)
        *cp++ = ' ';
    }
    *cp = '\0';
    print_line(cf->print_fh, 0, print_args->format, line_buf);
  }

  print_separator = FALSE;

  /* Update the progress bar when it gets to this value. */
  progbar_nextstep = 0;
  /* When we reach the value that triggers a progress bar update,
     bump that value by this amount. */
  progbar_quantum = cf->count/N_PROGBAR_UPDATES;
  /* Count of packets at which we've looked. */
  count = 0;

  stop_flag = FALSE;
  progbar = create_progress_dlg("Printing", "Stop", &stop_flag);

  /* Iterate through the list of packets, printing the packets that
     were selected by the current display filter.  */
  for (fdata = cf->plist; fdata != NULL; fdata = fdata->next) {
    /* Update the progress bar, but do it only N_PROGBAR_UPDATES times;
       when we update it, we have to run the GTK+ main loop to get it
       to repaint what's pending, and doing so may involve an "ioctl()"
       to see if there's any pending input from an X server, and doing
       that for every packet can be costly, especially on a big file. */
    if (count >= progbar_nextstep) {
      /* let's not divide by zero. I should never be started
       * with count == 0, so let's assert that
       */
      g_assert(cf->count > 0);

      update_progress_dlg(progbar, (gfloat) count / cf->count);

      progbar_nextstep += progbar_quantum;
    }

    if (stop_flag) {
      /* Well, the user decided to abort the printing.  Just stop.

         XXX - note that what got generated before they did that
         will get printed, as we're piping to a print program; we'd
         have to write to a file and then hand that to the print
         program to make it actually not print anything. */
      break;
    }

    count++;
    /* Check to see if we are suppressing unmarked packets, if so, 
     * suppress them and then proceed to check for visibility.
     */
    if (((print_args->suppress_unmarked && fdata->flags.marked ) ||
        !(print_args->suppress_unmarked)) && fdata->flags.passed_dfilter) {
      /* XXX - do something with "err" */
      wtap_seek_read (cf->wth, fdata->file_off, &cf->pseudo_header,
                        cf->pd, fdata->cap_len, &err);
      if (print_args->print_summary) {
        /* Fill in the column information, but don't bother creating
           the logical protocol tree. */
        edt = epan_dissect_new(FALSE, FALSE);
        epan_dissect_run(edt, &cf->pseudo_header, cf->pd, fdata, &cf->cinfo);
        epan_dissect_fill_in_columns(edt);
        cp = &line_buf[0];
        line_len = 0;
        for (i = 0; i < cf->cinfo.num_cols; i++) {
          /* Find the length of the string for this column. */
          column_len = strlen(cf->cinfo.col_data[i]);
          if (col_widths[i] > column_len)
            column_len = col_widths[i];

          /* Make sure there's room in the line buffer for the column; if not,
             double its length. */
          line_len += column_len + 1;   /* "+1" for space */
          if (line_len > line_buf_len) {
            line_buf_len *= 2;
            line_buf = g_realloc(line_buf, line_buf_len + 1);
          }

          /* Right-justify the packet number column. */
          if (cf->cinfo.col_fmt[i] == COL_NUMBER)
            sprintf(cp, "%*s", col_widths[i], cf->cinfo.col_data[i]);
          else
            sprintf(cp, "%-*s", col_widths[i], cf->cinfo.col_data[i]);
          cp += column_len;
          if (i != cf->cinfo.num_cols - 1)
            *cp++ = ' ';
        }
        *cp = '\0';
        print_line(cf->print_fh, 0, print_args->format, line_buf);
      } else {
        if (print_separator)
          print_line(cf->print_fh, 0, print_args->format, "");

        /* Create the logical protocol tree, complete with the display
           representation of the items; we don't need the columns here,
           however. */
        edt = epan_dissect_new(TRUE, TRUE);
        epan_dissect_run(edt, &cf->pseudo_header, cf->pd, fdata, NULL);

        /* Print the information in that tree. */
        proto_tree_print(print_args, edt, cf->print_fh);

        if (print_args->print_hex) {
          /* Print the full packet data as hex. */
          print_hex_data(cf->print_fh, print_args->format, edt);
        }

        /* Print a blank line if we print anything after this. */
        print_separator = TRUE;
      }
      epan_dissect_free(edt);
    }
  }

  /* We're done printing the packets; destroy the progress bar. */
  destroy_progress_dlg(progbar);

  if (col_widths != NULL)
    g_free(col_widths);
  if (line_buf != NULL)
    g_free(line_buf);

  print_finale(cf->print_fh, print_args->format);

  close_print_dest(print_args->to_file, cf->print_fh);
 
  cf->print_fh = NULL;

  return TRUE;
}

/* Scan through the packet list and change all columns that use the
   "command-line-specified" time stamp format to use the current
   value of that format. */
void
change_time_formats(capture_file *cf)
{
  frame_data *fdata;
  progdlg_t *progbar;
  gboolean stop_flag;
  guint32 progbar_quantum;
  guint32 progbar_nextstep;
  unsigned int count;
  int row;
  int i;
  GtkStyle  *pl_style;

  /* Are there any columns with time stamps in the "command-line-specified"
     format?

     XXX - we have to force the "column is writable" flag on, as it
     might be off from the last frame that was dissected. */
  col_set_writable(&cf->cinfo, TRUE);
  if (!check_col(&cf->cinfo, COL_CLS_TIME)) {
    /* No, there aren't any columns in that format, so we have no work
       to do. */
    return;
  }

  /* Freeze the packet list while we redo it, so we don't get any
     screen updates while it happens. */
  freeze_clist(cf);

  /* Update the progress bar when it gets to this value. */
  progbar_nextstep = 0;
  /* When we reach the value that triggers a progress bar update,
     bump that value by this amount. */
  progbar_quantum = cf->count/N_PROGBAR_UPDATES;
  /* Count of packets at which we've looked. */
  count = 0;

  stop_flag = FALSE;
  progbar = create_progress_dlg("Changing time display", "Stop", &stop_flag);

  /* Iterate through the list of packets, checking whether the packet
     is in a row of the summary list and, if so, whether there are
     any columns that show the time in the "command-line-specified"
     format and, if so, update that row. */
  for (fdata = cf->plist; fdata != NULL; fdata = fdata->next) {
    /* Update the progress bar, but do it only N_PROGBAR_UPDATES times;
       when we update it, we have to run the GTK+ main loop to get it
       to repaint what's pending, and doing so may involve an "ioctl()"
       to see if there's any pending input from an X server, and doing
       that for every packet can be costly, especially on a big file. */
    if (count >= progbar_nextstep) {
      /* let's not divide by zero. I should never be started
       * with count == 0, so let's assert that
       */
      g_assert(cf->count > 0);

      update_progress_dlg(progbar, (gfloat) count / cf->count);

      progbar_nextstep += progbar_quantum;
    }

    if (stop_flag) {
      /* Well, the user decided to abort the redisplay.  Just stop.

         XXX - this leaves the time field in the old format in
         frames we haven't yet processed.  So it goes; should we
         simply not offer them the option of stopping? */
      break;
    }

    count++;

    /* Find what row this packet is in. */
    row = gtk_clist_find_row_from_data(GTK_CLIST(packet_list), fdata);

    if (row != -1) {
      /* This packet is in the summary list, on row "row". */

      for (i = 0; i < cf->cinfo.num_cols; i++) {
        if (cf->cinfo.fmt_matx[i][COL_CLS_TIME]) {
          /* This is one of the columns that shows the time in
             "command-line-specified" format; update it. */
          cf->cinfo.col_buf[i][0] = '\0';
          col_set_cls_time(fdata, &cf->cinfo, i);
          gtk_clist_set_text(GTK_CLIST(packet_list), row, i,
                             cf->cinfo.col_data[i]);
        }
      }
    }
  }

  /* We're done redisplaying the packets; destroy the progress bar. */
  destroy_progress_dlg(progbar);

  /* Set the column widths of those columns that show the time in
     "command-line-specified" format. */
  pl_style = gtk_widget_get_style(packet_list);
  for (i = 0; i < cf->cinfo.num_cols; i++) {
    if (cf->cinfo.fmt_matx[i][COL_CLS_TIME]) {
      gtk_clist_set_column_width(GTK_CLIST(packet_list), i,
        gdk_string_width(pl_style->font, get_column_longest_string(COL_CLS_TIME)));
    }
  }

  /* Unfreeze the packet list. */
  thaw_clist(cf);
}

gboolean
find_packet(capture_file *cf, dfilter_t *sfcode)
{
  frame_data *start_fd;
  frame_data *fdata;
  frame_data *new_fd = NULL;
  progdlg_t *progbar = NULL;
  gboolean stop_flag;
  guint32 progbar_quantum;
  guint32 progbar_nextstep;
  unsigned int count;
  int err;
  gboolean frame_matched;
  int row;
  epan_dissect_t        *edt;

  start_fd = cf->current_frame;
  if (start_fd != NULL)  {
    /* Iterate through the list of packets, starting at the packet we've
       picked, calling a routine to run the filter on the packet, see if
       it matches, and stop if so.  */
    count = 0;
    fdata = start_fd;

    /* Update the progress bar when it gets to this value.  We start at
       20, not 0, so that we don't get a progress bar until we've
       checked at least that many frames, so that a very quick search
       doesn't pop up and immediately destroy a progress bar.

       XXX - should use a timer?  Like 50 ms. */
    progbar_nextstep = 20;
    /* When we reach the value that triggers a progress bar update,
       bump that value by this amount. */
    progbar_quantum = cf->count/N_PROGBAR_UPDATES;

    stop_flag = FALSE;

    fdata = start_fd;
    for (;;) {
      /* Update the progress bar, but do it only N_PROGBAR_UPDATES times;
         when we update it, we have to run the GTK+ main loop to get it
         to repaint what's pending, and doing so may involve an "ioctl()"
         to see if there's any pending input from an X server, and doing
         that for every packet can be costly, especially on a big file. */
      if (count >= progbar_nextstep) {
        /* let's not divide by zero. I should never be started
         * with count == 0, so let's assert that
         */
        g_assert(cf->count > 0);

        /* Create the progress bar if it doesn't exist; we don't create it
           immediately, so that we don't have it appear and immediately
           disappear if the search is quick. */
        if (progbar == NULL)
           progbar = create_progress_dlg("Searching", "Cancel", &stop_flag);
        
        update_progress_dlg(progbar, (gfloat) count / cf->count);

        progbar_nextstep += progbar_quantum;
      }

      if (stop_flag) {
        /* Well, the user decided to abort the search.  Go back to the
           frame where we started. */
        new_fd = start_fd;
        break;
      }

      /* Go past the current frame. */
      if (cf->sbackward) {
        /* Go on to the previous frame. */
        fdata = fdata->prev;
        if (fdata == NULL)
          fdata = cf->plist_end;        /* wrap around */
      } else {
        /* Go on to the next frame. */
        fdata = fdata->next;
        if (fdata == NULL)
          fdata = cf->plist;    /* wrap around */
      }

      count++;

      /* Is this packet in the display? */
      if (fdata->flags.passed_dfilter) {
        /* Yes.  Does it match the search filter? */
        /* XXX - do something with "err" */
        wtap_seek_read(cf->wth, fdata->file_off, &cf->pseudo_header,
                        cf->pd, fdata->cap_len, &err);
        edt = epan_dissect_new(TRUE, FALSE);
        epan_dissect_prime_dfilter(edt, sfcode);
        epan_dissect_run(edt, &cf->pseudo_header, cf->pd, fdata, NULL);
        frame_matched = dfilter_apply_edt(sfcode, edt);
        epan_dissect_free(edt);
        if (frame_matched) {
          new_fd = fdata;
          break;        /* found it! */
        }
      }

      if (fdata == start_fd) {
        /* We're back to the frame we were on originally, and that frame
           doesn't match the search filter.  The search failed. */
        break;
      }
    }

    /* We're done scanning the packets; destroy the progress bar, if
       we created it. */
    if (progbar != NULL)
      destroy_progress_dlg(progbar);
  }

  if (new_fd != NULL) {
    /* We found a frame.  Find what row it's in. */
    row = gtk_clist_find_row_from_data(GTK_CLIST(packet_list), new_fd);
    g_assert(row != -1);

    /* Select that row, make it the focus row, and make it visible. */
    set_selected_row(row);
    return TRUE;        /* success */
  } else
    return FALSE;       /* failure */
}

goto_result_t
goto_frame(capture_file *cf, guint fnumber)
{
  frame_data *fdata;
  int row;

  for (fdata = cf->plist; fdata != NULL && fdata->num < fnumber; fdata = fdata->next)
    ;

  if (fdata == NULL)
    return NO_SUCH_FRAME;       /* we didn't find that frame */
  if (!fdata->flags.passed_dfilter)
    return FRAME_NOT_DISPLAYED; /* the frame with that number isn't displayed */

  /* We found that frame, and it's currently being displayed.
     Find what row it's in. */
  row = gtk_clist_find_row_from_data(GTK_CLIST(packet_list), fdata);
  g_assert(row != -1);

  /* Select that row, make it the focus row, and make it visible. */
  set_selected_row(row);
  return FOUND_FRAME;
}

/* Select the packet on a given row. */
void
select_packet(capture_file *cf, int row)
{
  frame_data *fdata;
  int err;

  /* Get the frame data struct pointer for this frame */
  fdata = (frame_data *) gtk_clist_get_row_data(GTK_CLIST(packet_list), row);

  if (fdata == NULL) {
    /* XXX - if a GtkCList's selection mode is GTK_SELECTION_BROWSE, when
       the first entry is added to it by "real_insert_row()", that row
       is selected (see "real_insert_row()", in "gtk/gtkclist.c", in both
       our version and the vanilla GTK+ version).

       This means that a "select-row" signal is emitted; this causes
       "packet_list_select_cb()" to be called, which causes "select_packet()"
       to be called.

       "select_packet()" fetches, above, the data associated with the
       row that was selected; however, as "gtk_clist_append()", which
       called "real_insert_row()", hasn't yet returned, we haven't yet
       associated any data with that row, so we get back a null pointer.

       We can't assume that there's only one frame in the frame list,
       either, as we may be filtering the display.

       We therefore assume that, if "row" is 0, i.e. the first row
       is being selected, and "cf->first_displayed" equals
       "cf->last_displayed", i.e. there's only one frame being
       displayed, that frame is the frame we want.

       This means we have to set "cf->first_displayed" and
       "cf->last_displayed" before adding the row to the
       GtkCList; see the comment in "add_packet_to_packet_list()". */

       if (row == 0 && cf->first_displayed == cf->last_displayed)
         fdata = cf->first_displayed;
  }

  /* Record that this frame is the current frame. */
  cf->current_frame = fdata;

  /* Get the data in that frame. */
  /* XXX - do something with "err" */
  wtap_seek_read (cf->wth, fdata->file_off, &cf->pseudo_header,
                        cf->pd, fdata->cap_len, &err);

  /* Create the logical protocol tree. */
  if (cf->edt != NULL) {
    epan_dissect_free(cf->edt);
    cf->edt = NULL;
  }
  /* We don't need the columns here. */
  cf->edt = epan_dissect_new(TRUE, TRUE);
  epan_dissect_run(cf->edt, &cf->pseudo_header, cf->pd, cf->current_frame,
          NULL);

  /* Display the GUI protocol tree and hex dump.
     XXX - why do we dump core if we call "proto_tree_draw()"
     before calling "add_byte_views()"? */
  add_byte_views(cf->edt, tree_view, byte_nb_ptr);
  proto_tree_draw(cf->edt->tree, tree_view);

  /* A packet is selected. */
  set_menus_for_selected_packet(TRUE);
}

/* Unselect the selected packet, if any. */
void
unselect_packet(capture_file *cf)
{
  /* Destroy the epan_dissect_t for the unselected packet. */
  if (cf->edt != NULL) {
    epan_dissect_free(cf->edt);
    cf->edt = NULL;
  }

  /* Clear out the display of that packet. */
  clear_tree_and_hex_views();

  /* No packet is selected. */
  set_menus_for_selected_packet(FALSE);

  /* No protocol tree means no selected field. */
  unselect_field();
}

/* Set the selected row and the focus row of the packet list to the specified
   row, and make it visible if it's not currently visible. */
static void
set_selected_row(int row)
{
  if (gtk_clist_row_is_visible(GTK_CLIST(packet_list), row) != GTK_VISIBILITY_FULL)
    gtk_clist_moveto(GTK_CLIST(packet_list), row, -1, 0.0, 0.0);

  /* XXX - why is there no "gtk_clist_set_focus_row()", so that we
     can make the row for the frame we found the focus row?

     See

 http://www.gnome.org/mailing-lists/archives/gtk-list/2000-January/0038.shtml

     */
  GTK_CLIST(packet_list)->focus_row = row;

  gtk_clist_select_row(GTK_CLIST(packet_list), row, -1);
}

/* Unset the selected protocol tree field, if any. */
void
unselect_field(void)
{
  statusbar_pop_field_msg();
  finfo_selected = NULL;
  set_menus_for_selected_tree_row(FALSE);
}

/*
 * Mark a particular frame.
 */
void
mark_frame(capture_file *cf, frame_data *frame)
{
  frame->flags.marked = TRUE;
  cf->marked_count++;
}

/*
 * Unmark a particular frame.
 */
void
unmark_frame(capture_file *cf, frame_data *frame)
{
  frame->flags.marked = FALSE;
  cf->marked_count--;
}

static void
freeze_clist(capture_file *cf)
{
  int i;

  /* Make the column sizes static, so they don't adjust while
     we're reading the capture file (freezing the clist doesn't
     seem to suffice). */
  for (i = 0; i < cf->cinfo.num_cols; i++)
    gtk_clist_set_column_auto_resize(GTK_CLIST(packet_list), i, FALSE);
  gtk_clist_freeze(GTK_CLIST(packet_list));
}

static void
thaw_clist(capture_file *cf)
{
  int i;

  for (i = 0; i < cf->cinfo.num_cols; i++) {
    if (get_column_resize_type(cf->cinfo.col_fmt[i]) == RESIZE_MANUAL) {
      /* Set this column's width to the appropriate value. */
      gtk_clist_set_column_width(GTK_CLIST(packet_list), i,
                                cf->cinfo.col_width[i]);
    } else {
      /* Make this column's size dynamic, so that it adjusts to the
         appropriate size. */
      gtk_clist_set_column_auto_resize(GTK_CLIST(packet_list), i, TRUE);
    }
  }
  gtk_clist_thaw(GTK_CLIST(packet_list));

  /* Hopefully, the columns have now gotten their appropriate sizes;
     make them resizeable - a column that auto-resizes cannot be
     resized by the user, and *vice versa*. */
  for (i = 0; i < cf->cinfo.num_cols; i++)
    gtk_clist_set_column_resizeable(GTK_CLIST(packet_list), i, TRUE);
}

/*
 * Save a capture to a file, in a particular format, saving either
 * all packets, all currently-displayed packets, or all marked packets.
 *
 * Returns TRUE if it succeeds, FALSE otherwise; if it fails, it pops
 * up a message box for the failure.
 */
gboolean
save_cap_file(char *fname, capture_file *cf, gboolean save_filtered,
                gboolean save_marked, guint save_format)
{
  gchar        *from_filename;
  gchar        *name_ptr, *save_msg, *save_fmt = " Saving: %s...";
  size_t        msg_len;
  int           err;
  gboolean      do_copy;
  wtap_dumper  *pdh;
  frame_data   *fdata;
  struct wtap_pkthdr hdr;
  union wtap_pseudo_header pseudo_header;
  guint8        pd[65536];
  struct stat   infile, outfile;

  name_ptr = get_basename(fname);
  msg_len = strlen(name_ptr) + strlen(save_fmt) + 2;
  save_msg = g_malloc(msg_len);
  snprintf(save_msg, msg_len, save_fmt, name_ptr);
  statusbar_push_file_msg(save_msg);
  g_free(save_msg);

  /* 
   * Check that the from file is not the same as to file 
   * We do it here so we catch all cases ...
   * Unfortunately, the file requester gives us an absolute file
   * name and the read file name may be relative (if supplied on
   * the command line). From Joerg Mayer.
   */
   infile.st_ino = 1;   /* These prevent us from getting equality         */
   outfile.st_ino = 2;  /* If one or other of the files is not accessible */
   stat(cf->filename, &infile);
   stat(fname, &outfile);
   if (infile.st_ino == outfile.st_ino) {
    simple_dialog(ESD_TYPE_CRIT, NULL, 
                      "Can't save over current capture file: %s!",
                      cf->filename);
    goto fail;
  }

  if (!save_filtered && !save_marked && save_format == cf->cd_t) {
    /* We're not filtering packets, and we're saving it in the format
       it's already in, so we can just move or copy the raw data. */

    if (cf->is_tempfile) {
      /* The file being saved is a temporary file from a live
         capture, so it doesn't need to stay around under that name;
         first, try renaming the capture buffer file to the new name. */
#ifndef WIN32
      if (rename(cf->filename, fname) == 0) {
        /* That succeeded - there's no need to copy the source file. */
        from_filename = NULL;
        do_copy = FALSE;
      } else {
        if (errno == EXDEV) {
          /* They're on different file systems, so we have to copy the
             file. */
          do_copy = TRUE;
          from_filename = cf->filename;
        } else {
          /* The rename failed, but not because they're on different
             file systems - put up an error message.  (Or should we
             just punt and try to copy?  The only reason why I'd
             expect the rename to fail and the copy to succeed would
             be if we didn't have permission to remove the file from
             the temporary directory, and that might be fixable - but
             is it worth requiring the user to go off and fix it?) */
          simple_dialog(ESD_TYPE_CRIT, NULL,
                                file_rename_error_message(errno), fname);
          goto fail;
        }
      }
#else
      do_copy = TRUE;
      from_filename = cf->filename;
#endif
    } else {
      /* It's a permanent file, so we should copy it, and not remove the
         original. */
      do_copy = TRUE;
      from_filename = cf->filename;
    }

    if (do_copy) {
      /* Copy the file, if we haven't moved it. */
      if (!copy_binary_file(from_filename, fname))
        goto fail;
    }
  } else {
    /* Either we're filtering packets, or we're saving in a different
       format; we can't do that by copying or moving the capture file,
       we have to do it by writing the packets out in Wiretap. */
    pdh = wtap_dump_open(fname, save_format, cf->lnk_t, cf->snap, &err);
    if (pdh == NULL) {
      simple_dialog(ESD_TYPE_CRIT, NULL,
                        file_open_error_message(err, TRUE, save_format), fname);
      goto fail;
    }

    /* XXX - have a way to save only the packets currently selected by
       the display filter or the marked ones.

       If we do that, should we make that file the current file?  If so,
       it means we can no longer get at the other packets.  What does
       NetMon do? */
    for (fdata = cf->plist; fdata != NULL; fdata = fdata->next) {
      /* XXX - do a progress bar */
      if ((!save_filtered && !save_marked) ||
          (save_filtered && fdata->flags.passed_dfilter && !save_marked) ||
          (save_marked && fdata->flags.marked && !save_filtered) ||
          (save_filtered && save_marked && fdata->flags.passed_dfilter &&
           fdata->flags.marked)) {
        /* Either :
           - we're saving all frames, or
           - we're saving filtered frames and this one passed the display filter or
           - we're saving marked frames (and it has been marked) or
           - we're saving filtered _and_ marked frames,
           save it. */
        hdr.ts.tv_sec = fdata->abs_secs;
        hdr.ts.tv_usec = fdata->abs_usecs;
        hdr.caplen = fdata->cap_len;
        hdr.len = fdata->pkt_len;
        hdr.pkt_encap = fdata->lnk_t;
        if (!wtap_seek_read(cf->wth, fdata->file_off, &pseudo_header,
                pd, fdata->cap_len, &err)) {
          simple_dialog(ESD_TYPE_CRIT, NULL,
                                file_read_error_message(err), cf->filename);
          wtap_dump_close(pdh, &err);
          goto fail;
        }

        if (!wtap_dump(pdh, &hdr, &pseudo_header, pd, &err)) {
          simple_dialog(ESD_TYPE_CRIT, NULL,
                                file_write_error_message(err), fname);
          wtap_dump_close(pdh, &err);
          goto fail;
        }
      }
    }

    if (!wtap_dump_close(pdh, &err)) {
      simple_dialog(ESD_TYPE_WARN, NULL,
                file_close_error_message(err), fname);
      goto fail;
    }
  }

  /* Pop the "Saving:" message off the status bar. */
  statusbar_pop_file_msg();
  if (!save_filtered && !save_marked) {
    /* We saved the entire capture, not just some packets from it.
       Open and read the file we saved it to.

       XXX - this is somewhat of a waste; we already have the
       packets, all this gets us is updated file type information
       (which we could just stuff into "cf"), and having the new
       file be the one we have opened and from which we're reading
       the data, and it means we have to spend time opening and
       reading the file, which could be a significant amount of
       time if the file is large. */
    cf->user_saved = TRUE;

    if ((err = open_cap_file(fname, FALSE, cf)) == 0) {
      /* XXX - report errors if this fails?
         What should we return if it fails or is aborted? */
      switch (read_cap_file(cf, &err)) {

      case READ_SUCCESS:
      case READ_ERROR:
        /* Just because we got an error, that doesn't mean we were unable
           to read any of the file; we handle what we could get from the
           file. */
        break;

      case READ_ABORTED:
        /* The user bailed out of re-reading the capture file; the
           capture file has been closed - just return (without
           changing any menu settings; "close_cap_file()" set them
           correctly for the "no capture file open" state). */
        break;
      }
      set_menus_for_unsaved_capture_file(FALSE);
    }
  }
  return TRUE;

fail:
  /* Pop the "Saving:" message off the status bar. */
  statusbar_pop_file_msg();
  return FALSE;
}

char *
file_open_error_message(int err, gboolean for_writing, int file_type)
{
  char *errmsg;
  static char errmsg_errno[1024+1];

  switch (err) {

  case WTAP_ERR_NOT_REGULAR_FILE:
    errmsg = "The file \"%s\" is a \"special file\" or socket or other non-regular file.";
    break;

  case WTAP_ERR_RANDOM_OPEN_PIPE:
    /* Seen only when opening a capture file for reading. */
    errmsg = "The file \"%s\" is a pipe or FIFO; Ethereal cannot read pipe or FIFO files.";
    break;

  case WTAP_ERR_FILE_UNKNOWN_FORMAT:
  case WTAP_ERR_UNSUPPORTED:
    /* Seen only when opening a capture file for reading. */
    errmsg = "The file \"%s\" is not a capture file in a format Ethereal understands.";
    break;

  case WTAP_ERR_CANT_WRITE_TO_PIPE:
    /* Seen only when opening a capture file for writing. */
    snprintf(errmsg_errno, sizeof(errmsg_errno),
             "The file \"%%s\" is a pipe, and %s capture files cannot be "
             "written to a pipe.", wtap_file_type_string(file_type));
    errmsg = errmsg_errno;
    break;

  case WTAP_ERR_UNSUPPORTED_FILE_TYPE:
    /* Seen only when opening a capture file for writing. */
    errmsg = "Ethereal does not support writing capture files in that format.";
    break;

  case WTAP_ERR_UNSUPPORTED_ENCAP:
  case WTAP_ERR_ENCAP_PER_PACKET_UNSUPPORTED:
    if (for_writing)
      errmsg = "Ethereal cannot save this capture in that format.";
    else
      errmsg = "The file \"%s\" is a capture for a network type that Ethereal doesn't support.";
    break;

  case WTAP_ERR_BAD_RECORD:
    errmsg = "The file \"%s\" appears to be damaged or corrupt.";
    break;

  case WTAP_ERR_CANT_OPEN:
    if (for_writing)
      errmsg = "The file \"%s\" could not be created for some unknown reason.";
    else
      errmsg = "The file \"%s\" could not be opened for some unknown reason.";
    break;

  case WTAP_ERR_SHORT_READ:
    errmsg = "The file \"%s\" appears to have been cut short"
             " in the middle of a packet or other data.";
    break;

  case WTAP_ERR_SHORT_WRITE:
    errmsg = "A full header couldn't be written to the file \"%s\".";
    break;

  case ENOENT:
    if (for_writing)
      errmsg = "The path to the file \"%s\" does not exist.";
    else
      errmsg = "The file \"%s\" does not exist.";
    break;

  case EACCES:
    if (for_writing)
      errmsg = "You do not have permission to create or write to the file \"%s\".";
    else
      errmsg = "You do not have permission to read the file \"%s\".";
    break;

  case EISDIR:
    errmsg = "\"%s\" is a directory (folder), not a file.";
    break;

  default:
    snprintf(errmsg_errno, sizeof(errmsg_errno),
                    "The file \"%%s\" could not be %s: %s.",
                                for_writing ? "created" : "opened",
                                wtap_strerror(err));
    errmsg = errmsg_errno;
    break;
  }
  return errmsg;
}

static char *
file_rename_error_message(int err)
{
  char *errmsg;
  static char errmsg_errno[1024+1];

  switch (err) {

  case ENOENT:
    errmsg = "The path to the file \"%s\" does not exist.";
    break;

  case EACCES:
    errmsg = "You do not have permission to move the capture file to \"%s\".";
    break;

  default:
    snprintf(errmsg_errno, sizeof(errmsg_errno),
                    "The file \"%%s\" could not be moved: %s.",
                                wtap_strerror(err));
    errmsg = errmsg_errno;
    break;
  }
  return errmsg;
}

char *
file_read_error_message(int err)
{
  static char errmsg_errno[1024+1];

  snprintf(errmsg_errno, sizeof(errmsg_errno),
                  "An error occurred while reading from the file \"%%s\": %s.",
                                wtap_strerror(err));
  return errmsg_errno;
}

char *
file_write_error_message(int err)
{
  char *errmsg;
  static char errmsg_errno[1024+1];

  switch (err) {

  case ENOSPC:
    errmsg = "The file \"%s\" could not be saved because there is no space left on the file system.";
    break;

#ifdef EDQUOT
  case EDQUOT:
    errmsg = "The file \"%s\" could not be saved because you are too close to, or over, your disk quota.";
    break;
#endif

  default:
    snprintf(errmsg_errno, sizeof(errmsg_errno),
                    "An error occurred while writing to the file \"%%s\": %s.",
                                wtap_strerror(err));
    errmsg = errmsg_errno;
    break;
  }
  return errmsg;
}

/* Check for write errors - if the file is being written to an NFS server,
   a write error may not show up until the file is closed, as NFS clients
   might not send writes to the server until the "write()" call finishes,
   so that the write may fail on the server but the "write()" may succeed. */
static char *
file_close_error_message(int err)
{
  char *errmsg;
  static char errmsg_errno[1024+1];

  switch (err) {

  case WTAP_ERR_CANT_CLOSE:
    errmsg = "The file \"%s\" couldn't be closed for some unknown reason.";
    break;

  case WTAP_ERR_SHORT_WRITE:
    errmsg = "Not all the packets could be written to the file \"%s\".";
    break;

  case ENOSPC:
    errmsg = "The file \"%s\" could not be saved because there is no space left on the file system.";
    break;

#ifdef EDQUOT
  case EDQUOT:
    errmsg = "The file \"%s\" could not be saved because you are too close to, or over, your disk quota.";
    break;
#endif

  default:
    snprintf(errmsg_errno, sizeof(errmsg_errno),
                    "An error occurred while closing the file \"%%s\": %s.",
                                wtap_strerror(err));
    errmsg = errmsg_errno;
    break;
  }
  return errmsg;
}


/* Copies a file in binary mode, for those operating systems that care about
 * such things.
 * Returns TRUE on success, FALSE on failure. If a failure, it also
 * displays a simple dialog window with the error message.
 */
static gboolean
copy_binary_file(char *from_filename, char *to_filename)
{
        int           from_fd, to_fd, nread, nwritten, err;
        guint8        pd[65536]; /* XXX - Hmm, 64K here, 64K in save_cap_file(),
                                    perhaps we should make just one 64K buffer. */

      /* Copy the raw bytes of the file. */
      from_fd = open(from_filename, O_RDONLY | O_BINARY);
      if (from_fd < 0) {
        err = errno;
        simple_dialog(ESD_TYPE_CRIT, NULL,
                        file_open_error_message(err, TRUE, 0), from_filename);
        goto done;
      }

      /* Use open() instead of creat() so that we can pass the O_BINARY
         flag, which is relevant on Win32; it appears that "creat()"
         may open the file in text mode, not binary mode, but we want
         to copy the raw bytes of the file, so we need the output file
         to be open in binary mode. */
      to_fd = open(to_filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
      if (to_fd < 0) {
        err = errno;
        simple_dialog(ESD_TYPE_CRIT, NULL,
                        file_open_error_message(err, TRUE, 0), to_filename);
        close(from_fd);
        goto done;
      }

      while ((nread = read(from_fd, pd, sizeof pd)) > 0) {
        nwritten = write(to_fd, pd, nread);
        if (nwritten < nread) {
          if (nwritten < 0)
            err = errno;
          else
            err = WTAP_ERR_SHORT_WRITE;
          simple_dialog(ESD_TYPE_CRIT, NULL,
                                file_write_error_message(err), to_filename);
          close(from_fd);
          close(to_fd);
          goto done;
        }
      }
      if (nread < 0) {
        err = errno;
        simple_dialog(ESD_TYPE_CRIT, NULL,
                        file_read_error_message(err), from_filename);
        close(from_fd);
        close(to_fd);
        goto done;
      }
      close(from_fd);
      if (close(to_fd) < 0) {
        err = errno;
        simple_dialog(ESD_TYPE_CRIT, NULL,
                file_close_error_message(err), to_filename);
        goto done;
      }

      return TRUE;

   done:
      return FALSE;
}