/* capture_sync.c
 * Synchronisation between Ethereal capture parent and child instances
 *
 * $Id: capture_sync.c 14484 2005-05-30 04:46:25Z ulfl $
 *
 * 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

#ifdef HAVE_LIBPCAP

#include <pcap.h>

#include <glib.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>

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

#include <signal.h>

#ifdef HAVE_SYS_WAIT_H
# include <sys/wait.h>
#endif

#ifndef _WIN32
/*
 * Define various POSIX macros (and, in the case of WCOREDUMP, non-POSIX
 * macros) on UNIX systems that don't have them.
 */
#ifndef WIFEXITED
# define WIFEXITED(status)	(((status) & 0177) == 0)
#endif
#ifndef WIFSTOPPED
# define WIFSTOPPED(status)	(((status) & 0177) == 0177)
#endif
#ifndef WIFSIGNALED
# define WIFSIGNALED(status)	(!WIFSTOPPED(status) && !WIFEXITED(status))
#endif
#ifndef WEXITSTATUS
# define WEXITSTATUS(status)	((status) >> 8)
#endif
#ifndef WTERMSIG
# define WTERMSIG(status)	((status) & 0177)
#endif
#ifndef WCOREDUMP
# define WCOREDUMP(status)	((status) & 0200)
#endif
#ifndef WSTOPSIG
# define WSTOPSIG(status)	((status) >> 8)
#endif
#endif /* _WIN32 */

#include <epan/packet.h>
#include <epan/prefs.h>

#include "globals.h"
#include "file.h"

#include "capture.h"
#include "capture_sync.h"
#include "simple_dialog.h"

#ifdef _WIN32
#include "capture-wpcap.h"
#endif
#include "ui_util.h"
#include "log.h"

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

#ifdef _WIN32
#include <process.h>    /* For spawning child process */
#endif

/* Win32 needs the O_BINARY flag for open() */
#ifndef O_BINARY
#define O_BINARY	0
#endif


#ifndef _WIN32
static char *sync_pipe_signame(int);
#endif


static gboolean sync_pipe_input_cb(gint source, gpointer user_data);
static void sync_pipe_wait_for_child(capture_options *capture_opts);

/* Size of buffer to hold decimal representation of
   signed/unsigned 64-bit int */
#define SP_DECISIZE 20

/*
 * Indications sent out on the sync pipe.
 */
#define SP_FILE	        'F'	    /* the name of the recently opened file */
#define SP_ERROR_MSG    'E'     /* error message */
#define SP_PACKET_COUNT 'P'     /* count of packets captured since last message */
#define SP_DROPS        'D'	    /* count of packets dropped in capture */
#define SP_QUIT         'Q'     /* capture quit message (from parent to child) */


/* write a message to the recipient pipe in the standard format 
   (3 digit message length (excluding length and indicator field), 
   1 byte message indicator and the rest is the message) */
static void
pipe_write_block(int pipe, char indicator, int len, const char *msg)
{
    char lenbuf[3+1+1]; /* 3 digit len + indicator + zero terminator */
    int ret;

    /*g_warning("write %d enter", pipe);*/

    g_assert(len < 1000);
    g_assert(indicator < '0' || indicator > '9');

    /* write header (3 digit len + indicator) */
    g_snprintf(lenbuf, 5, "%03u%c", len, indicator);

    ret = write(pipe, lenbuf, strlen(lenbuf));
    if(ret == -1) {
        return;
    }

    /* write value (if we have one) */
    if(len) {
        /*g_warning("write %d indicator: %c value len: %u msg: %s", pipe, indicator, len, msg);*/
        ret = write(pipe, msg, len);
        if(ret == -1) {
            return;
        }
    } else {
        /*g_warning("write %d indicator: %c no value", pipe, indicator);*/
    }

    /*g_warning("write %d leave", pipe);*/
}


/* read a message from the sending pipe in the standard format 
   (3 digit message length (excluding length and indicator field), 
   1 byte message indicator and the rest is the message) */
int
pipe_read_block(int pipe, char *indicator, int len, char *msg) {
    int required;
    int newly;
    char header[4];
    int offset;


    /* read header (3 digit len and indicator) */
    required = 4;
    offset = 0;
    while(required) {
        newly = read(pipe, &header[offset], required);
        if (newly == 0) {
            /* EOF */
            /*g_warning("read %d header empty (capture closed)", pipe);*/
            return newly;
        }
        if (newly < 0) {
            /* error */
            /*g_warning("read %d header error: %s", pipe, strerror(errno));*/
            return newly;
        }

        required -= newly;
        offset += newly;
    }

    /* convert header values */
    *indicator = header[3];
    required = atoi(header);

    /* only indicator with no value? */
    if(required == 0) {
        /*g_warning("read %d indicator: %c empty value", pipe, *indicator);*/
        return 4;
    }

    g_assert(required <= len);
    len = required;

    /* read value */
    offset = 0;
    while(required) {
        newly = read(pipe, &msg[offset], required);
        if (newly == -1) {
            /* error */
            /*g_warning("read %d value error, indicator: %u", pipe, *indicator);*/
            return newly;
        }

        required -= newly;
        offset += newly;
    }

    /*g_warning("read %d ok indicator: %c len: %u msg: %s", pipe, *indicator, len, msg);*/
    return len + 4;
}

void
sync_pipe_packet_count_to_parent(int packet_count)
{
    char tmp[SP_DECISIZE+1+1];

    g_snprintf(tmp, sizeof(tmp), "%d", packet_count);

    g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_DEBUG, "sync_pipe_packet_count_to_parent: %s", tmp);

    pipe_write_block(1, SP_PACKET_COUNT, strlen(tmp)+1, tmp);
}

void
sync_pipe_filename_to_parent(const char *filename)
{
    g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_DEBUG, "sync_pipe_filename_to_parent: %s", filename);

    pipe_write_block(1, SP_FILE, strlen(filename)+1, filename);
}

void
sync_pipe_errmsg_to_parent(const char *errmsg)
{
    g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_DEBUG, "sync_pipe_errmsg_to_parent: %s", errmsg);

    pipe_write_block(1, SP_ERROR_MSG, strlen(errmsg)+1, errmsg);
}

void
sync_pipe_drops_to_parent(int drops)
{
	char tmp[SP_DECISIZE+1+1];


    g_snprintf(tmp, sizeof(tmp), "%d", drops);

    g_log(LOG_DOMAIN_CAPTURE_CHILD, G_LOG_LEVEL_DEBUG, "sync_pipe_drops_to_parent: %s", tmp);

    pipe_write_block(1, SP_DROPS, strlen(tmp)+1, tmp);
}


#ifdef _WIN32

static void
signal_pipe_capquit_to_child(capture_options *capture_opts)
{

    g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG, "signal_pipe_capquit_to_child");

    pipe_write_block(capture_opts->signal_pipe_fd, SP_QUIT, 0, NULL);
}
#endif


/* Add a string pointer to a NULL-terminated array of string pointers. */
static char **
sync_pipe_add_arg(char **args, int *argc, char *arg)
{
  /* Grow the array; "*argc" currently contains the number of string
     pointers, *not* counting the NULL pointer at the end, so we have
     to add 2 in order to get the new size of the array, including the
     new pointer and the terminating NULL pointer. */
  args = g_realloc(args, (*argc + 2) * sizeof (char *));

  /* Stuff the pointer into the penultimate element of the array, which
     is the one at the index specified by "*argc". */
  args[*argc] = arg;

  /* Now bump the count. */
  (*argc)++;

  /* We overwrite the NULL pointer; put it back right after the
     element we added. */
  args[*argc] = NULL;

  return args;
}

#ifdef _WIN32
/* Given a string, return a pointer to a quote-encapsulated version of
   the string, so we can pass it as an argument with "spawnvp" even
   if it contains blanks. */
char *
sync_pipe_quote_encapsulate(const char *string)
{
  char *encapsulated_string;

  encapsulated_string = g_new(char, strlen(string) + 3);
  sprintf(encapsulated_string, "\"%s\"", string);
  return encapsulated_string;
}
#endif



#define ARGV_NUMBER_LEN 24

gboolean
sync_pipe_start(capture_options *capture_opts) {
    char ssnap[ARGV_NUMBER_LEN];
    char scount[ARGV_NUMBER_LEN];
    char sfilesize[ARGV_NUMBER_LEN];
    char sfile_duration[ARGV_NUMBER_LEN];
    char sring_num_files[ARGV_NUMBER_LEN];
    char sautostop_files[ARGV_NUMBER_LEN];
    char sautostop_filesize[ARGV_NUMBER_LEN];
    char sautostop_duration[ARGV_NUMBER_LEN];
#ifdef _WIN32
    char buffer_size[ARGV_NUMBER_LEN];
    char sync_pipe_fd[ARGV_NUMBER_LEN];
    char signal_pipe_fd[ARGV_NUMBER_LEN];
    char *fontstring;
    char *filterstring;
    char *savefilestring;
    int signal_pipe[2];                     /* pipe used to send messages from parent to child (currently only stop) */
#else
    char errmsg[1024+1];
#endif
    int argc;
    char **argv;
    enum PIPES { PIPE_READ, PIPE_WRITE };   /* Constants 0 and 1 for PIPE_READ and PIPE_WRITE */
    int sync_pipe[2];                       /* pipe used to send messages from child to parent */


    g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG, "sync_pipe_start");
#ifdef LOG_CAPTURE_VERBOSE
    capture_opts_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG, capture_opts);
#endif

    capture_opts->fork_child = -1;

    /* Allocate the string pointer array with enough space for the
       terminating NULL pointer. */
    argc = 0;
    argv = g_malloc(sizeof (char *));
    *argv = NULL;

    /* Now add those arguments used on all platforms. */
    argv = sync_pipe_add_arg(argv, &argc, CHILD_NAME);

    argv = sync_pipe_add_arg(argv, &argc, "-i");
    argv = sync_pipe_add_arg(argv, &argc, capture_opts->iface);

    if (capture_opts->has_snaplen) {
      argv = sync_pipe_add_arg(argv, &argc, "-s");
      sprintf(ssnap,"%d",capture_opts->snaplen);
      argv = sync_pipe_add_arg(argv, &argc, ssnap);
    }

    if (capture_opts->linktype != -1) {
      argv = sync_pipe_add_arg(argv, &argc, "-y");
#ifdef HAVE_PCAP_DATALINK_VAL_TO_NAME
      sprintf(ssnap,"%s",pcap_datalink_val_to_name(capture_opts->linktype));
#else
      /* XXX - just treat it as a number */
      sprintf(ssnap,"%d",capture_opts->linktype);
#endif
      argv = sync_pipe_add_arg(argv, &argc, ssnap);
    }

    if(capture_opts->multi_files_on) {
      if (capture_opts->has_autostop_filesize) {
        argv = sync_pipe_add_arg(argv, &argc, "-b");
        sprintf(sfilesize,"filesize:%d",capture_opts->autostop_filesize);
        argv = sync_pipe_add_arg(argv, &argc, sfilesize);
      }

      if (capture_opts->has_file_duration) {
        argv = sync_pipe_add_arg(argv, &argc, "-b");
        sprintf(sfile_duration,"duration:%d",capture_opts->file_duration);
        argv = sync_pipe_add_arg(argv, &argc, sfile_duration);
      }

      if (capture_opts->has_ring_num_files) {
        argv = sync_pipe_add_arg(argv, &argc, "-b");
        sprintf(sring_num_files,"files:%d",capture_opts->ring_num_files);
        argv = sync_pipe_add_arg(argv, &argc, sring_num_files);
      }

      if (capture_opts->has_autostop_files) {
        argv = sync_pipe_add_arg(argv, &argc, "-a");
        sprintf(sautostop_files,"files:%d",capture_opts->autostop_files);
        argv = sync_pipe_add_arg(argv, &argc, sautostop_files);
      }
    } else {
        if (capture_opts->has_autostop_filesize) {
          argv = sync_pipe_add_arg(argv, &argc, "-a");
          sprintf(sautostop_filesize,"filesize:%d",capture_opts->autostop_filesize);
          argv = sync_pipe_add_arg(argv, &argc, sautostop_filesize);
        }
    }

    if (capture_opts->has_autostop_packets) {
      argv = sync_pipe_add_arg(argv, &argc, "-c");
      sprintf(scount,"%d",capture_opts->autostop_packets);
      argv = sync_pipe_add_arg(argv, &argc, scount);
    }

    if (capture_opts->has_autostop_duration) {
      argv = sync_pipe_add_arg(argv, &argc, "-a");
      sprintf(sautostop_duration,"duration:%d",capture_opts->autostop_duration);
      argv = sync_pipe_add_arg(argv, &argc, sautostop_duration);
    }

    if (!capture_opts->show_info) {
      argv = sync_pipe_add_arg(argv, &argc, "-H");
    }

    if (!capture_opts->promisc_mode)
      argv = sync_pipe_add_arg(argv, &argc, "-p");

#ifdef _WIN32
    /* Create a pipe for the child process */
    /* (inrease this value if you have trouble while fast capture file switches) */
    if(_pipe(sync_pipe, 5120, O_BINARY) < 0) {
      /* Couldn't create the pipe between parent and child. */
      simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK, "Couldn't create sync pipe: %s",
                        strerror(errno));
      g_free(argv);
      return FALSE;
    }

    /* Create a pipe for the parent process */
    if(_pipe(signal_pipe, 512, O_BINARY) < 0) {
      /* Couldn't create the signal pipe between parent and child. */
      simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK, "Couldn't create signal pipe: %s",
                        strerror(errno));
      close(sync_pipe[PIPE_READ]);
      close(sync_pipe[PIPE_WRITE]);
      g_free(argv);
      return FALSE;
    }

    capture_opts->signal_pipe_fd = signal_pipe[PIPE_WRITE];

    argv = sync_pipe_add_arg(argv, &argc, "-B");
    sprintf(buffer_size,"%d",capture_opts->buffer_size);
    argv = sync_pipe_add_arg(argv, &argc, buffer_size);

    /* Convert font name to a quote-encapsulated string and pass to child */
    argv = sync_pipe_add_arg(argv, &argc, "-m");
    fontstring = sync_pipe_quote_encapsulate(prefs.PREFS_GUI_FONT_NAME);
    argv = sync_pipe_add_arg(argv, &argc, fontstring);

    /* Convert sync pipe write handle to a string and pass to child */
    argv = sync_pipe_add_arg(argv, &argc, "-Z");
    sprintf(sync_pipe_fd,"sync:%d",sync_pipe[PIPE_WRITE]);
    argv = sync_pipe_add_arg(argv, &argc, sync_pipe_fd);

    /* Convert signal pipe read handle to a string and pass to child */
    argv = sync_pipe_add_arg(argv, &argc, "-Z");
    sprintf(signal_pipe_fd,"signal:%d",signal_pipe[PIPE_READ]);
    argv = sync_pipe_add_arg(argv, &argc, signal_pipe_fd);

    /* Convert filter string to a quote delimited string and pass to child */
    filterstring = NULL;
    if (capture_opts->cfilter != NULL && strlen(capture_opts->cfilter) != 0) {
      argv = sync_pipe_add_arg(argv, &argc, "-f");
      filterstring = sync_pipe_quote_encapsulate(capture_opts->cfilter);
      argv = sync_pipe_add_arg(argv, &argc, filterstring);
    }

    /* Convert save file name to a quote delimited string and pass to child */
    savefilestring = NULL;
    if(capture_opts->save_file) {
      argv = sync_pipe_add_arg(argv, &argc, "-w");
      savefilestring = sync_pipe_quote_encapsulate(capture_opts->save_file);
      argv = sync_pipe_add_arg(argv, &argc, savefilestring);
    }

    /* Spawn process */
    capture_opts->fork_child = spawnvp(_P_NOWAIT, ethereal_path, argv);
    g_free(fontstring);
    if (filterstring) {
      g_free(filterstring);
    }
    if(savefilestring) {
      g_free(savefilestring);
    }

    /* child own's the read side now, close our handle */
    close(signal_pipe[PIPE_READ]);
#else
    if (pipe(sync_pipe) < 0) {
      /* Couldn't create the pipe between parent and child. */
      simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK, "Couldn't create sync pipe: %s",
			strerror(errno));
      g_free(argv);
      return FALSE;
    }

    argv = sync_pipe_add_arg(argv, &argc, "-m");
    argv = sync_pipe_add_arg(argv, &argc, prefs.PREFS_GUI_FONT_NAME);

    if (capture_opts->cfilter != NULL && capture_opts->cfilter != 0) {
      argv = sync_pipe_add_arg(argv, &argc, "-f");
      argv = sync_pipe_add_arg(argv, &argc, capture_opts->cfilter);
    }

    if(capture_opts->save_file) {
      argv = sync_pipe_add_arg(argv, &argc, "-w");
      argv = sync_pipe_add_arg(argv, &argc, capture_opts->save_file);
    }

    if ((capture_opts->fork_child = fork()) == 0) {
      /*
       * Child process - run Ethereal with the right arguments to make
       * it just pop up the live capture dialog box and capture with
       * the specified capture parameters, writing to the specified file.
       *
       * args: -i interface specification
       * -w file to write
       * -W file descriptor to write
       * -c count to capture
       * -s snaplen
       * -m / -b fonts
       * -f "filter expression"
       */
      close(1);
      dup(sync_pipe[PIPE_WRITE]);
      close(sync_pipe[PIPE_READ]);
      execvp(ethereal_path, argv);
      snprintf(errmsg, sizeof errmsg, "Couldn't run %s in child process: %s",
		ethereal_path, strerror(errno));
      sync_pipe_errmsg_to_parent(errmsg);

      /* Exit with "_exit()", so that we don't close the connection
         to the X server (and cause stuff buffered up by our parent but
	 not yet sent to be sent, as that stuff should only be sent by
	 our parent). */
      _exit(2);
    }
#endif

    /* Parent process - read messages from the child process over the
       sync pipe. */
    g_free(argv);	/* free up arg array */

    /* Close the write side of the pipe, so that only the child has it
       open, and thus it completely closes, and thus returns to us
       an EOF indication, if the child closes it (either deliberately
       or by exiting abnormally). */
    close(sync_pipe[PIPE_WRITE]);

    if (capture_opts->fork_child == -1) {
      /* We couldn't even create the child process. */
      simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK,
			"Couldn't create child process: %s", strerror(errno));
      close(sync_pipe[PIPE_READ]);
#ifdef _WIN32
      close(signal_pipe[PIPE_WRITE]);
#endif
      return FALSE;
    }

    /* we might wait for a moment till child is ready, so update screen now */
    main_window_update();

    /* We were able to set up to read the capture file;
       arrange that our callback be called whenever it's possible
       to read from the sync pipe, so that it's called when
       the child process wants to tell us something. */

    /* we have a running capture, now wait for the real capture filename */
    pipe_input_set_handler(sync_pipe[PIPE_READ], (gpointer) capture_opts, 
        &capture_opts->fork_child, sync_pipe_input_cb);

    return TRUE;
}

/* There's stuff to read from the sync pipe, meaning the child has sent
   us a message, or the sync pipe has closed, meaning the child has
   closed it (perhaps because it exited). */
static gboolean 
sync_pipe_input_cb(gint source, gpointer user_data)
{
  capture_options *capture_opts = (capture_options *)user_data;
#define BUFSIZE	4096
  char buffer[BUFSIZE+1];
  int  nread;
  char indicator;


  nread = pipe_read_block(source, &indicator, BUFSIZE, buffer);
  if(nread <= 0) {
    g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG, "sync_pipe_input_cb: child has closed sync_pipe");

    /* The child has closed the sync pipe, meaning it's not going to be
       capturing any more packets.  Pick up its exit status, and
       complain if it did anything other than exit with status 0. */
    sync_pipe_wait_for_child(capture_opts);

#ifdef _WIN32
    close(capture_opts->signal_pipe_fd);
#endif
    capture_input_closed(capture_opts);
    return FALSE;
  }

  switch(indicator) {
  case SP_FILE:
      if(!capture_input_new_file(capture_opts, buffer)) {
        g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG, "sync_pipe_input_cb: file failed, closing capture");

        /* We weren't able to open the new capture file; user has been
           alerted. Close the sync pipe. */
        /* XXX - is it safe to close the pipe inside this callback? */
        close(source);

        /* the child has send us a filename which we couldn't open.
           this probably means, the child is creating files faster than we can handle it.
           this should only be the case for very fast file switches
           we can't do much more than telling the child to stop
           (this is the emergency brake if user e.g. wants to switch files every second) */
        sync_pipe_stop(capture_opts);
      }
      break;
  case SP_PACKET_COUNT:
    nread = atoi(buffer);
    g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG, "sync_pipe_input_cb: new packets %u", nread);
    capture_input_new_packets(capture_opts, nread);
    break;
  case SP_ERROR_MSG:
    g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_MESSAGE, "Error message from child: \"%s\"", buffer);
    simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK, buffer);
    /* the capture child will close the sync_pipe, nothing to do for now */
    break;
  case SP_DROPS:
    g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_INFO, "%d packet%s dropped", atoi(buffer), plurality(atoi(buffer), "", "s"));
    cf_set_drops_known(capture_opts->cf, TRUE);
    cf_set_drops(capture_opts->cf, atoi(buffer));
    break;
  default:
      g_assert_not_reached();
  }

  return TRUE;
}



/* the child process is going down, wait until it's completely terminated */
static void
sync_pipe_wait_for_child(capture_options *capture_opts)
{
  int  wstatus;


  g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG, "sync_pipe_wait_for_child: wait till child closed");
  g_assert(capture_opts->fork_child != -1);

#ifdef _WIN32
  /* XXX - analyze the wait status and display more information
     in the dialog box?
     XXX - set "fork_child" to -1 if we find it exited? */
  if (_cwait(&wstatus, capture_opts->fork_child, _WAIT_CHILD) == -1) {
    simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK,
		"Child capture process stopped unexpectedly");
  }
#else
  if (wait(&wstatus) != -1) {
    if (WIFEXITED(wstatus)) {
      /* The child exited; display its exit status, if it seems uncommon (0=ok, 1=error) */
      /* the child will inform us about errors through the sync_pipe, which will popup */
      /* an error message, so don't popup another one */

      /* XXX - if there are situations where the child won't send us such an error message, */
      /* this should be fixed in the child and not here! */
      if (WEXITSTATUS(wstatus) != 0 && WEXITSTATUS(wstatus) != 1) {
        simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK,
		      "Child capture process exited: exit status %d",
		      WEXITSTATUS(wstatus));
      }
    } else if (WIFSTOPPED(wstatus)) {
      /* It stopped, rather than exiting.  "Should not happen." */
      simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK,
		    "Child capture process stopped: %s",
		    sync_pipe_signame(WSTOPSIG(wstatus)));
    } else if (WIFSIGNALED(wstatus)) {
      /* It died with a signal. */
      simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK,
		    "Child capture process died: %s%s",
		    sync_pipe_signame(WTERMSIG(wstatus)),
		    WCOREDUMP(wstatus) ? " - core dumped" : "");
    } else {
      /* What?  It had to either have exited, or stopped, or died with
         a signal; what happened here? */
      simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK,
		    "Child capture process died: wait status %#o", wstatus);
    }
  }

  /* No more child process. */
  capture_opts->fork_child = -1;
#endif

  g_log(LOG_DOMAIN_CAPTURE, G_LOG_LEVEL_DEBUG, "sync_pipe_wait_for_child: capture child closed");
}


#ifndef _WIN32
/* convert signal to corresponding name */
static char *
sync_pipe_signame(int sig)
{
  char *sigmsg;
  static char sigmsg_buf[6+1+3+1];

  switch (sig) {

  case SIGHUP:
    sigmsg = "Hangup";
    break;

  case SIGINT:
    sigmsg = "Interrupted";
    break;

  case SIGQUIT:
    sigmsg = "Quit";
    break;

  case SIGILL:
    sigmsg = "Illegal instruction";
    break;

  case SIGTRAP:
    sigmsg = "Trace trap";
    break;

  case SIGABRT:
    sigmsg = "Abort";
    break;

  case SIGFPE:
    sigmsg = "Arithmetic exception";
    break;

  case SIGKILL:
    sigmsg = "Killed";
    break;

  case SIGBUS:
    sigmsg = "Bus error";
    break;

  case SIGSEGV:
    sigmsg = "Segmentation violation";
    break;

  /* http://metalab.unc.edu/pub/Linux/docs/HOWTO/GCC-HOWTO
     Linux is POSIX compliant.  These are not POSIX-defined signals ---
     ISO/IEC 9945-1:1990 (IEEE Std 1003.1-1990), paragraph B.3.3.1.1 sez:

	``The signals SIGBUS, SIGEMT, SIGIOT, SIGTRAP, and SIGSYS
	were omitted from POSIX.1 because their behavior is
	implementation dependent and could not be adequately catego-
	rized.  Conforming implementations may deliver these sig-
	nals, but must document the circumstances under which they
	are delivered and note any restrictions concerning their
	delivery.''

     So we only check for SIGSYS on those systems that happen to
     implement them (a system can be POSIX-compliant and implement
     them, it's just that POSIX doesn't *require* a POSIX-compliant
     system to implement them).
   */

#ifdef SIGSYS
  case SIGSYS:
    sigmsg = "Bad system call";
    break;
#endif

  case SIGPIPE:
    sigmsg = "Broken pipe";
    break;

  case SIGALRM:
    sigmsg = "Alarm clock";
    break;

  case SIGTERM:
    sigmsg = "Terminated";
    break;

  default:
    sprintf(sigmsg_buf, "Signal %d", sig);
    sigmsg = sigmsg_buf;
    break;
  }
  return sigmsg;
}
#endif


/* user wants to stop the capture run */
void
sync_pipe_stop(capture_options *capture_opts)
{
  /* XXX - in which cases this will be 0? */
  if (capture_opts->fork_child != -1 && capture_opts->fork_child != 0) {
#ifndef _WIN32
    /* send the SIGUSR1 signal to close the capture child gracefully. */
    kill(capture_opts->fork_child, SIGUSR1);
#else
    /* Win32 doesn't have the kill() system call, use the special signal pipe 
       instead to close the capture child gracefully. */
    signal_pipe_capquit_to_child(capture_opts);
#endif
  }
}


/* Ethereal has to exit, force the capture child to close */
void
sync_pipe_kill(capture_options *capture_opts)
{
  /* XXX - in which cases this will be 0? */
  if (capture_opts->fork_child != -1 && capture_opts->fork_child != 0) {
#ifndef _WIN32
      kill(capture_opts->fork_child, SIGTERM);	/* SIGTERM so it can clean up if necessary */
#else
      /* XXX: this is not the preferred method of closing a process!
       * the clean way would be getting the process id of the child process,
       * then getting window handle hWnd of that process (using EnumChildWindows),
       * and then do a SendMessage(hWnd, WM_CLOSE, 0, 0) 
       *
       * Unfortunately, I don't know how to get the process id from the
       * handle.  OpenProcess will get an handle (not a window handle)
       * from the process ID; it will not get a window handle from the
       * process ID.  (How could it?  A process can have more than one
       * window.)
       *
       * Hint: GenerateConsoleCtrlEvent() will only work if both processes are 
       * running in the same console; that's not necessarily the case for
       * us, as we might not be running in a console.
       * And this also will require to have the process id.
       */
      TerminateProcess((HANDLE) (capture_opts->fork_child), 0);
#endif
  }
}

#endif /* HAVE_LIBPCAP */
