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i bet a lot of people didn't know what ssh 1.2.16 had a nice license.
well, except for the patent issues.  someone in sweden (forget their
name at the moment) cleaned out most of the patented code, and now
this code removes rsa code.  when this is done, it will link against
libssl, but the work isn't completely done yet.  then we need to bring
this up to modern days, featurewise.

/*

minfd.c

Author: David Mazieres <dm@lcs.mit.edu>
	Contributed to be part of ssh.

Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
                   All rights reserved

Created: Tue Aug 22 17:25:30 1995 ylo

*/

#include "includes.h"
RCSID("$Id: minfd.c,v 1.1 1999/09/26 20:53:36 deraadt Exp $");

#include <sys/resource.h> /* Needed by fdlim.h */
#include "fdlim.h"
#include "minfd.h"

#ifdef _PATH_BSHELL
#define DEFAULT_SHELL           _PATH_BSHELL
#else
#define DEFAULT_SHELL           "/bin/sh"
#endif

static int
_get_permanent_fd(const char *shellpath)
{
  const char *shell;
  struct passwd *pwd;
  int fdmin;
  int fdlim;
  int fd;
  int i;

  if (!shellpath) 
    {
      if (!shellpath)
	shellpath = getenv("SHELL");
      if (!shellpath)
	if ((pwd = getpwuid(getuid())))
	  shellpath = pwd->pw_shell;
      if (!shellpath)
	shellpath = DEFAULT_SHELL;
    }
  if ((shell = strrchr(shellpath, '/')))
    shell++;
  else
    shell = shellpath;
  
  for (i = 0; strcmp(mafd[i].shell, shell); i++)
    if (i == MAFD_MAX - 1)
      return -1;

  fdmin = mafd[i].fd;
  fdlim = fdlim_get(0);
  
  if (fdmin < fdlim) 
    {
      /* First try to find a file descriptor as high as possible without
	 upping the limit */
      fd = fdlim - 1;
      while (fd >= fdmin)
	{
	  if (fcntl(fd, F_GETFL, NULL) < 0)
	    return fd;
	  fd--;
	}
    }

  fd = fdlim;
  for (;;) 
    {
      if (fdlim_set(fd + 1) < 0)
	return -1;
      if (fcntl(fd, F_GETFL, NULL) < 0)
	break;
      fd++;
    }
  return fd;
}

int
get_permanent_fd(const char *shellpath)
{
  static int fd = -2;

  if (fd >= -1)
    return fd;
  fd = _get_permanent_fd(shellpath);
  if (fd < 0)
    fd = -1;
  return fd;
}