filter.c

mutt-1.5.12 源代码。linux 下邮件接受的工具。

/*
 * Copyright (C) 1996-2000 Michael R. Elkins.
 * 
 *     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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */ 

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

#include "mutt.h"

#include <unistd.h>
#include <stdlib.h>
#include <sys/wait.h>

/* Invokes a commmand on a pipe and optionally connects its stdin and stdout
 * to the specified handles.
 */
pid_t
mutt_create_filter_fd (const char *cmd, FILE **in, FILE **out, FILE **err,
		       int fdin, int fdout, int fderr)
{
  int pin[2], pout[2], perr[2], thepid;

  if (in)
  {
    *in = 0;
    if (pipe (pin) == -1)
      return (-1);
  }

  if (out)
  {
    *out = 0;
    if (pipe (pout) == -1)
    {
      if (in)
      {
	close (pin[0]);
	close (pin[1]);
      }
      return (-1);
    }
  }

  if (err)
  {
    *err = 0;
    if (pipe (perr) == -1)
    {
      if (in)
      {
	close (pin[0]);
	close (pin[1]);
      }
      if (out)
      {
	close (pout[0]);
	close (pout[1]);
      }
      return (-1);
    }
  }

  mutt_block_signals_system ();

  if ((thepid = fork ()) == 0)
  {
    mutt_unblock_signals_system (0);

    if (in)
    {
      close (pin[1]);
      dup2 (pin[0], 0);
      close (pin[0]);
    }
    else if (fdin != -1)
    {
      dup2 (fdin, 0);
      close (fdin);
    }

    if (out)
    {
      close (pout[0]);
      dup2 (pout[1], 1);
      close (pout[1]);
    }
    else if (fdout != -1)
    {
      dup2 (fdout, 1);
      close (fdout);
    }

    if (err)
    {
      close (perr[0]);
      dup2 (perr[1], 2);
      close (perr[1]);
    }
    else if (fderr != -1)
    {
      dup2 (fderr, 2);
      close (fderr);
    }

    execl (EXECSHELL, "sh", "-c", cmd, NULL);
    _exit (127);
  }
  else if (thepid == -1)
  {
    mutt_unblock_signals_system (1);

    if (in)
    {
      close (pin[0]);
      close (pin[1]);
    }
    
    if (out)
    {
      close (pout[0]);
      close (pout[1]);
    }

    if (err)
    {
      close (perr[0]);
      close (perr[1]);
    }

    return (-1);
  }

  if (out)
  {
    close (pout[1]);
    *out = fdopen (pout[0], "r");
  }

  if (in)
  {
    close (pin[0]);
    *in = fdopen (pin[1], "w");
  }

  if (err)
  {
    close (perr[1]);
    *err = fdopen (perr[0], "r");
  }

  return (thepid);
}

pid_t mutt_create_filter (const char *s, FILE **in, FILE **out, FILE **err)
{
  return (mutt_create_filter_fd (s, in, out, err, -1, -1, -1));
}

int mutt_wait_filter (pid_t pid)
{
  int rc;
  
  waitpid (pid, &rc, 0);
  mutt_unblock_signals_system (1);
  rc = WIFEXITED (rc) ? WEXITSTATUS (rc) : -1;
  
  return rc;
}