code:
/* Copyright (C) 1996,1997,1998,1999,2000,2001, 2002, 2004, 2006, 2009, 2010 Free Software Foundation, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 3 of
 * the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

/* See stime.c for comments on why _POSIX_C_SOURCE is not always defined. */
#define _LARGEFILE64_SOURCE      /* ask for stat64 etc */
#ifdef __hpux
#define _POSIX_C_SOURCE 199506L  /* for readdir_r */
#endif

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include <alloca.h>

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

#include "libguile/_scm.h"
#include "libguile/smob.h"
#include "libguile/feature.h"
#include "libguile/fports.h"
#include "libguile/private-gc.h"  /* for SCM_MAX */
#include "libguile/iselect.h"
#include "libguile/strings.h"
#include "libguile/vectors.h"
#include "libguile/dynwind.h"

#include "libguile/validate.h"
#include "libguile/filesys.h"

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

#ifdef HAVE_DIRECT_H
#include <direct.h>
#endif

#ifdef TIME_WITH_SYS_TIME
# include <sys/time.h>
# include <time.h>
#else
# if HAVE_SYS_TIME_H
#  include <sys/time.h>
# else
#  include <time.h>
# endif
#endif

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

#ifdef LIBC_H_WITH_UNISTD_H
#include <libc.h>
#endif

#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif

#ifdef HAVE_STRING_H
#include <string.h>
#endif

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#ifdef HAVE_PWD_H
#include <pwd.h>
#endif

#if defined (__MINGW32__) || defined (_MSC_VER) || defined (__BORLANDC__)
# include "win32-dirent.h"
# define NAMLEN(dirent) strlen((dirent)->d_name)
/* The following bits are per AC_HEADER_DIRENT doco in the autoconf manual */
#elif HAVE_DIRENT_H
# include <dirent.h>
# define NAMLEN(dirent) strlen((dirent)->d_name)
#else
# define dirent direct
# define NAMLEN(dirent) (dirent)->d_namlen
# if HAVE_SYS_NDIR_H
#  include <sys/ndir.h>
# endif
# if HAVE_SYS_DIR_H
#  include <sys/dir.h>
# endif
# if HAVE_NDIR_H
#  include <ndir.h>
# endif
#endif

/* Some more definitions for the native Windows port. */
#ifdef __MINGW32__
# define mkdir(path, mode) mkdir (path)
# define fsync(fd) _commit (fd)
# define fchmod(fd, mode) (-1)
#endif /* __MINGW32__ */

/* dirfd() returns the file descriptor underlying a "DIR*" directory stream.
   Found on MacOS X for instance.  The following definition is for Solaris
   10, it's probably not right elsewhere, but that's ok, it shouldn't be
   used elsewhere.  Crib note: If we need more then gnulib has a dirfd.m4
   figuring out how to get the fd (dirfd function, dirfd macro, dd_fd field,
   or d_fd field).  */
#ifndef dirfd
#define dirfd(dirstream) ((dirstream)->dd_fd)
#endif

/* Two helper macros for an often used pattern */

#define STRING_SYSCALL(str,cstr,code)        \
  do {                                       \
    int eno;                                 \
    char *cstr = scm_to_locale_string (str); \
    SCM_SYSCALL (code);                      \
    eno = errno; free (cstr); errno = eno;   \
  } while (0)

#define STRING2_SYSCALL(str1,cstr1,str2,cstr2,code)  \
  do {                                               \
    int eno;                                         \
    char *cstr1, *cstr2;                             \
    scm_dynwind_begin (0);                             \
    cstr1 = scm_to_locale_string (str1);             \
    scm_dynwind_free (cstr1);                          \
    cstr2 = scm_to_locale_string (str2);             \
    scm_dynwind_free (cstr2);                          \
    SCM_SYSCALL (code);                              \
    eno = errno; scm_dynwind_end (); errno = eno;      \
  } while (0)

/* {Permissions}
 */

#ifdef HAVE_CHOWN
SCM_DEFINE (scm_chown, "chown", 3, 0, 0,
            (SCM object, SCM owner, SCM group),
	    "Change the ownership and group of the file referred to by @var{object} to\n"
	    "the integer values @var{owner} and @var{group}.  @var{object} can be\n"
	    "a string containing a file name or, if the platform\n"
	    "supports fchown, a port or integer file descriptor\n"
	    "which is open on the file.  The return value\n"
	    "is unspecified.\n\n"
	    "If @var{object} is a symbolic link, either the\n"
	    "ownership of the link or the ownership of the referenced file will be\n"
	    "changed depending on the operating system (lchown is\n"
	    "unsupported at present).  If @var{owner} or @var{group} is specified\n"
	    "as @code{-1}, then that ID is not changed.")
#define FUNC_NAME s_scm_chown
{
  int rv;

  object = SCM_COERCE_OUTPORT (object);

#ifdef HAVE_FCHOWN
  if (scm_is_integer (object) || (SCM_OPFPORTP (object)))
    {
      int fdes = (SCM_OPFPORTP (object)?
		  SCM_FPORT_FDES (object) : scm_to_int (object));

      SCM_SYSCALL (rv = fchown (fdes, scm_to_int (owner), scm_to_int (group)));
    }
  else
#endif
    {
      STRING_SYSCALL (object, c_object,
		      rv = chown (c_object,
				  scm_to_int (owner), scm_to_int (group)));
    }
  if (rv == -1)
    SCM_SYSERROR;
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME
#endif /* HAVE_CHOWN */

SCM_DEFINE (scm_chmod, "chmod", 2, 0, 0,
            (SCM object, SCM mode),
	    "Changes the permissions of the file referred to by @var{obj}.\n"
	    "@var{obj} can be a string containing a file name or a port or integer file\n"
	    "descriptor which is open on a file (in which case @code{fchmod} is used\n"
	    "as the underlying system call).\n"
	    "@var{mode} specifies\n"
	    "the new permissions as a decimal number, e.g., @code{(chmod \"foo\" #o755)}.\n"
	    "The return value is unspecified.")
#define FUNC_NAME s_scm_chmod
{
  int rv;
  int fdes;

  object = SCM_COERCE_OUTPORT (object);

  if (scm_is_integer (object) || SCM_OPFPORTP (object))
    {
      if (scm_is_integer (object))
	fdes = scm_to_int (object);
      else
	fdes = SCM_FPORT_FDES (object);
      SCM_SYSCALL (rv = fchmod (fdes, scm_to_int (mode)));
    }
  else
    {
      STRING_SYSCALL (object, c_object,
		      rv = chmod (c_object, scm_to_int (mode)));
    }
  if (rv == -1)
    SCM_SYSERROR;
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

SCM_DEFINE (scm_umask, "umask", 0, 1, 0,
            (SCM mode),
	    "If @var{mode} is omitted, returns a decimal number representing the current\n"
	    "file creation mask.  Otherwise the file creation mask is set to\n"
	    "@var{mode} and the previous value is returned.\n\n"
	    "E.g., @code{(umask #o022)} sets the mask to octal 22, decimal 18.")
#define FUNC_NAME s_scm_umask
{
  mode_t mask;
  if (SCM_UNBNDP (mode))
    {
      mask = umask (0);
      umask (mask);
    }
  else
    {
      mask = umask (scm_to_uint (mode));
    }
  return scm_from_uint (mask);
}
#undef FUNC_NAME

SCM_DEFINE (scm_open_fdes, "open-fdes", 2, 1, 0,
            (SCM path, SCM flags, SCM mode),
	    "Similar to @code{open} but return a file descriptor instead of\n"
	    "a port.")
#define FUNC_NAME s_scm_open_fdes
{
  int fd;
  int iflags;
  int imode;

  iflags = SCM_NUM2INT (2, flags);
  imode = SCM_NUM2INT_DEF (3, mode, 0666);
  STRING_SYSCALL (path, c_path, fd = open_or_open64 (c_path, iflags, imode));
  if (fd == -1)
    SCM_SYSERROR;
  return scm_from_int (fd);
}
#undef FUNC_NAME

SCM_DEFINE (scm_open, "open", 2, 1, 0,
            (SCM path, SCM flags, SCM mode),
	    "Open the file named by @var{path} for reading and/or writing.\n"
	    "@var{flags} is an integer specifying how the file should be opened.\n"
	    "@var{mode} is an integer specifying the permission bits of the file, if\n"
	    "it needs to be created, before the umask is applied.  The default is 666\n"
	    "(Unix itself has no default).\n\n"
	    "@var{flags} can be constructed by combining variables using @code{logior}.\n"
	    "Basic flags are:\n\n"
	    "@defvar O_RDONLY\n"
	    "Open the file read-only.\n"
	    "@end defvar\n"
	    "@defvar O_WRONLY\n"
	    "Open the file write-only.\n"
	    "@end defvar\n"
	    "@defvar O_RDWR\n"
	    "Open the file read/write.\n"
	    "@end defvar\n"
	    "@defvar O_APPEND\n"
	    "Append to the file instead of truncating.\n"
	    "@end defvar\n"
	    "@defvar O_CREAT\n"
	    "Create the file if it does not already exist.\n"
	    "@end defvar\n\n"
	    "See the Unix documentation of the @code{open} system call\n"
	    "for additional flags.")
#define FUNC_NAME s_scm_open
{
  SCM newpt;
  char *port_mode;
  int fd;
  int iflags;

  fd = scm_to_int (scm_open_fdes (path, flags, mode));
  iflags = SCM_NUM2INT (2, flags);
  if (iflags & O_RDWR)
    {
      if (iflags & O_APPEND)
	port_mode = "a+";
      else if (iflags & O_CREAT)
	port_mode = "w+";
      else
	port_mode = "r+";
    }
  else {
    if (iflags & O_APPEND)
      port_mode = "a";
    else if (iflags & O_WRONLY)
      port_mode = "w";
    else
      port_mode = "r";
  }
  newpt = scm_fdes_to_port (fd, port_mode, path);
  return newpt;
}
#undef FUNC_NAME

SCM_DEFINE (scm_close, "close", 1, 0, 0,
            (SCM fd_or_port),
	    "Similar to close-port (@pxref{Closing, close-port}),\n"
	    "but also works on file descriptors.  A side\n"
	    "effect of closing a file descriptor is that any ports using that file\n"
	    "descriptor are moved to a different file descriptor and have\n"
	    "their revealed counts set to zero.")
#define FUNC_NAME s_scm_close
{
  int rv;
  int fd;

  fd_or_port = SCM_COERCE_OUTPORT (fd_or_port);

  if (SCM_PORTP (fd_or_port))
    return scm_close_port (fd_or_port);
  fd = scm_to_int (fd_or_port);
  scm_evict_ports (fd);		/* see scsh manual.  */
  SCM_SYSCALL (rv = close (fd));
  /* following scsh, closing an already closed file descriptor is
     not an error.  */
  if (rv < 0 && errno != EBADF)
    SCM_SYSERROR;
  return scm_from_bool (rv >= 0);
}
#undef FUNC_NAME

SCM_DEFINE (scm_close_fdes, "close-fdes", 1, 0, 0,
            (SCM fd),
	    "A simple wrapper for the @code{close} system call.\n"
	    "Close file descriptor @var{fd}, which must be an integer.\n"
	    "Unlike close (@pxref{Ports and File Descriptors, close}),\n"
	    "the file descriptor will be closed even if a port is using it.\n"
	    "The return value is unspecified.")
#define FUNC_NAME s_scm_close_fdes
{
  int c_fd;
  int rv;

  c_fd = scm_to_int (fd);
  SCM_SYSCALL (rv = close (c_fd));
  if (rv < 0)
    SCM_SYSERROR;
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

/* {Files}
 */

SCM_SYMBOL (scm_sym_regular, "regular");
SCM_SYMBOL (scm_sym_directory, "directory");
#ifdef S_ISLNK
SCM_SYMBOL (scm_sym_symlink, "symlink");
#endif
SCM_SYMBOL (scm_sym_block_special, "block-special");
SCM_SYMBOL (scm_sym_char_special, "char-special");
SCM_SYMBOL (scm_sym_fifo, "fifo");
SCM_SYMBOL (scm_sym_sock, "socket");
SCM_SYMBOL (scm_sym_unknown, "unknown");

static SCM
scm_stat2scm (struct stat_or_stat64 *stat_temp)
{
  SCM ans = scm_c_make_vector (18, SCM_UNSPECIFIED);

  SCM_SIMPLE_VECTOR_SET(ans, 0, scm_from_ulong (stat_temp->st_dev));
  SCM_SIMPLE_VECTOR_SET(ans, 1, scm_from_ino_t_or_ino64_t (stat_temp->st_ino));
  SCM_SIMPLE_VECTOR_SET(ans, 2, scm_from_ulong (stat_temp->st_mode));
  SCM_SIMPLE_VECTOR_SET(ans, 3, scm_from_ulong (stat_temp->st_nlink));
  SCM_SIMPLE_VECTOR_SET(ans, 4, scm_from_ulong (stat_temp->st_uid));
  SCM_SIMPLE_VECTOR_SET(ans, 5, scm_from_ulong (stat_temp->st_gid));
#ifdef HAVE_STRUCT_STAT_ST_RDEV
  SCM_SIMPLE_VECTOR_SET(ans, 6, scm_from_ulong (stat_temp->st_rdev));
#else
  SCM_SIMPLE_VECTOR_SET(ans, 6, SCM_BOOL_F);
#endif
  SCM_SIMPLE_VECTOR_SET(ans, 7, scm_from_off_t_or_off64_t (stat_temp->st_size));
  SCM_SIMPLE_VECTOR_SET(ans, 8, scm_from_ulong (stat_temp->st_atime));
  SCM_SIMPLE_VECTOR_SET(ans, 9, scm_from_ulong (stat_temp->st_mtime));
  SCM_SIMPLE_VECTOR_SET(ans, 10, scm_from_ulong (stat_temp->st_ctime));
#ifdef HAVE_STRUCT_STAT_ST_BLKSIZE
  SCM_SIMPLE_VECTOR_SET(ans, 11, scm_from_ulong (stat_temp->st_blksize));
#else
  SCM_SIMPLE_VECTOR_SET(ans, 11, scm_from_ulong (4096L));
#endif
#ifdef HAVE_STRUCT_STAT_ST_BLOCKS
  SCM_SIMPLE_VECTOR_SET(ans, 12, scm_from_blkcnt_t_or_blkcnt64_t (stat_temp->st_blocks));
#else
  SCM_SIMPLE_VECTOR_SET(ans, 12, SCM_BOOL_F);
#endif
  {
    int mode = stat_temp->st_mode;

    if (S_ISREG (mode))
      SCM_SIMPLE_VECTOR_SET(ans, 13, scm_sym_regular);
    else if (S_ISDIR (mode))
      SCM_SIMPLE_VECTOR_SET(ans, 13, scm_sym_directory);
#ifdef S_ISLNK
    /* systems without symlinks probably don't have S_ISLNK */
    else if (S_ISLNK (mode))
      SCM_SIMPLE_VECTOR_SET(ans, 13, scm_sym_symlink);
#endif
    else if (S_ISBLK (mode))
      SCM_SIMPLE_VECTOR_SET(ans, 13, scm_sym_block_special);
    else if (S_ISCHR (mode))
      SCM_SIMPLE_VECTOR_SET(ans, 13, scm_sym_char_special);
    else if (S_ISFIFO (mode))
      SCM_SIMPLE_VECTOR_SET(ans, 13, scm_sym_fifo);
#ifdef S_ISSOCK
    else if (S_ISSOCK (mode))
      SCM_SIMPLE_VECTOR_SET(ans, 13, scm_sym_sock);
#endif
    else
      SCM_SIMPLE_VECTOR_SET(ans, 13, scm_sym_unknown);

    SCM_SIMPLE_VECTOR_SET(ans, 14, scm_from_int ((~S_IFMT) & mode));

    /* the layout of the bits in ve[14] is intended to be portable.
       If there are systems that don't follow the usual convention,
       the following could be used:

       tmp = 0;
       if (S_ISUID & mode) tmp += 1;
       tmp <<= 1;
       if (S_IRGRP & mode) tmp += 1;
       tmp <<= 1;
       if (S_ISVTX & mode) tmp += 1;
       tmp <<= 1;
       if (S_IRUSR & mode) tmp += 1;
       tmp <<= 1;
       if (S_IWUSR & mode) tmp += 1;
       tmp <<= 1;
       if (S_IXUSR & mode) tmp += 1;
       tmp <<= 1;
       if (S_IWGRP & mode) tmp += 1;
       tmp <<= 1;
       if (S_IXGRP & mode) tmp += 1;
       tmp <<= 1;
       if (S_IROTH & mode) tmp += 1;
       tmp <<= 1;
       if (S_IWOTH & mode) tmp += 1;
       tmp <<= 1;
       if (S_IXOTH & mode) tmp += 1;

       SCM_SIMPLE_VECTOR_SET(ans, 14, scm_from_int (tmp));

       */
  }
#ifdef HAVE_STRUCT_STAT_ST_ATIM
  SCM_SIMPLE_VECTOR_SET(ans, 15, scm_from_long (stat_temp->st_atim.tv_nsec));
#else
  SCM_SIMPLE_VECTOR_SET(ans, 15, SCM_I_MAKINUM (0));
#endif
#ifdef HAVE_STRUCT_STAT_ST_MTIM
  SCM_SIMPLE_VECTOR_SET(ans, 16, scm_from_long (stat_temp->st_mtim.tv_nsec));
#else
  SCM_SIMPLE_VECTOR_SET(ans, 16, SCM_I_MAKINUM (0));
#endif
#ifdef HAVE_STRUCT_STAT_ST_CTIM
  SCM_SIMPLE_VECTOR_SET(ans, 17, scm_from_ulong (stat_temp->st_ctim.tv_sec));
#else
  SCM_SIMPLE_VECTOR_SET(ans, 17, SCM_I_MAKINUM (0));
#endif

  return ans;
}

#ifdef __MINGW32__
/*
 * Try getting the appropiate stat buffer for a given file descriptor
 * under Windows. It differentiates between file, pipe and socket
 * descriptors.
 */
static int fstat_Win32 (int fdes, struct stat *buf)
{
  int error, optlen = sizeof (int);

  memset (buf, 0, sizeof (struct stat));

  /* Is this a socket ? */
  if (getsockopt (fdes, SOL_SOCKET, SO_ERROR, (void *) &error, &optlen) >= 0)
    {
      buf->st_mode = _S_IFSOCK | _S_IREAD | _S_IWRITE | _S_IEXEC;
      buf->st_nlink = 1;
      buf->st_atime = buf->st_ctime = buf->st_mtime = time (NULL);
      return 0;
    }
  /* Maybe a regular file or pipe ? */
  return fstat (fdes, buf);
}
#endif /* __MINGW32__ */

SCM_DEFINE (scm_stat, "stat", 1, 1, 0,
            (SCM object, SCM exception_on_error),
	    "Return an object containing various information about the file\n"
	    "determined by @var{obj}.  @var{obj} can be a string containing\n"
	    "a file name or a port or integer file descriptor which is open\n"
	    "on a file (in which case @code{fstat} is used as the underlying\n"
	    "system call).\n"
	    "\n"
            "If the optional @var{exception_on_error} argument is true, which\n"
            "is the default, an exception will be raised if the underlying\n"
            "system call returns an error, for example if the file is not\n"
            "found or is not readable. Otherwise, an error will cause\n"
            "@code{stat} to return @code{#f}."
	    "\n"
	    "The object returned by a successful call to @code{stat} can be\n"
            "passed as a single parameter to the following procedures, all of\n"
            "which return integers:\n"
	    "\n"
	    "@table @code\n"
	    "@item stat:dev\n"
	    "The device containing the file.\n"
	    "@item stat:ino\n"
	    "The file serial number, which distinguishes this file from all\n"
	    "other files on the same device.\n"
	    "@item stat:mode\n"
	    "The mode of the file.  This includes file type information and\n"
	    "the file permission bits.  See @code{stat:type} and\n"
	    "@code{stat:perms} below.\n"
	    "@item stat:nlink\n"
	    "The number of hard links to the file.\n"
	    "@item stat:uid\n"
	    "The user ID of the file's owner.\n"
	    "@item stat:gid\n"
	    "The group ID of the file.\n"
	    "@item stat:rdev\n"
	    "Device ID; this entry is defined only for character or block\n"
	    "special files.\n"
	    "@item stat:size\n"
	    "The size of a regular file in bytes.\n"
	    "@item stat:atime\n"
	    "The last access time for the file.\n"
	    "@item stat:mtime\n"
	    "The last modification time for the file.\n"
	    "@item stat:ctime\n"
	    "The last modification time for the attributes of the file.\n"
	    "@item stat:blksize\n"
	    "The optimal block size for reading or writing the file, in\n"
	    "bytes.\n"
	    "@item stat:blocks\n"
	    "The amount of disk space that the file occupies measured in\n"
	    "units of 512 byte blocks.\n"
	    "@end table\n"
	    "\n"
	    "In addition, the following procedures return the information\n"
	    "from stat:mode in a more convenient form:\n"
	    "\n"
	    "@table @code\n"
	    "@item stat:type\n"
	    "A symbol representing the type of file.  Possible values are\n"
	    "regular, directory, symlink, block-special, char-special, fifo,\n"
	    "socket and unknown\n"
	    "@item stat:perms\n"
	    "An integer representing the access permission bits.\n"
	    "@end table")
#define FUNC_NAME s_scm_stat
{
  int rv;
  int fdes;
  struct stat_or_stat64 stat_temp;

  if (scm_is_integer (object))
    {
#ifdef __MINGW32__
      SCM_SYSCALL (rv = fstat_Win32 (scm_to_int (object), &stat_temp));
#else
      SCM_SYSCALL (rv = fstat_or_fstat64 (scm_to_int (object), &stat_temp));
#endif
    }
  else if (scm_is_string (object))
    {
      char *file = scm_to_locale_string (object);
#ifdef __MINGW32__
      char *p;
      p = file + strlen (file) - 1;
      while (p > file && (*p == '/' || *p == '\\'))
	*p-- = '\0';
#endif
      SCM_SYSCALL (rv = stat_or_stat64 (file, &stat_temp));
      free (file);
    }
  else
    {
      object = SCM_COERCE_OUTPORT (object);
      SCM_VALIDATE_OPFPORT (1, object);
      fdes = SCM_FPORT_FDES (object);
#ifdef __MINGW32__
      SCM_SYSCALL (rv = fstat_Win32 (fdes, &stat_temp));
#else
      SCM_SYSCALL (rv = fstat_or_fstat64 (fdes, &stat_temp));
#endif
    }

  if (rv == -1)
    {
      if (SCM_UNBNDP (exception_on_error) || scm_is_true (exception_on_error))
        {
          int en = errno;
          SCM_SYSERROR_MSG ("~A: ~S",
                            scm_list_2 (scm_strerror (scm_from_int (en)),
                                        object),
                            en);
        }
      else
        return SCM_BOOL_F;
    }
  return scm_stat2scm (&stat_temp);
}
#undef FUNC_NAME

/* {Modifying Directories}
 */

#ifdef HAVE_LINK
SCM_DEFINE (scm_link, "link", 2, 0, 0,
            (SCM oldpath, SCM newpath),
	    "Creates a new name @var{newpath} in the file system for the\n"
	    "file named by @var{oldpath}.  If @var{oldpath} is a symbolic\n"
	    "link, the link may or may not be followed depending on the\n"
	    "system.")
#define FUNC_NAME s_scm_link
{
  int val;

  STRING2_SYSCALL (oldpath, c_oldpath,
		   newpath, c_newpath,
		   val = link (c_oldpath, c_newpath));
  if (val != 0)
    SCM_SYSERROR;
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME
#endif /* HAVE_LINK */

#ifdef HAVE_RENAME
#define my_rename rename
#else
static int
my_rename (const char *oldname, const char *newname)
{
  int rv;

  SCM_SYSCALL (rv = link (oldname, newname));
  if (rv == 0)
    {
      SCM_SYSCALL (rv = unlink (oldname));
      if (rv != 0)
	/* unlink failed.  remove new name */
	SCM_SYSCALL (unlink (newname));
    }
  return rv;
}
#endif

SCM_DEFINE (scm_rename, "rename-file", 2, 0, 0,
            (SCM oldname, SCM newname),
	    "Renames the file specified by @var{oldname} to @var{newname}.\n"
	    "The return value is unspecified.")
#define FUNC_NAME s_scm_rename
{
  int rv;

  STRING2_SYSCALL (oldname, c_oldname,
		   newname, c_newname,
		   rv = my_rename (c_oldname, c_newname));
  if (rv != 0)
    SCM_SYSERROR;
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

SCM_DEFINE (scm_delete_file, "delete-file", 1, 0, 0,
           (SCM str),
	    "Deletes (or \"unlinks\") the file specified by @var{path}.")
#define FUNC_NAME s_scm_delete_file
{
  int ans;
  STRING_SYSCALL (str, c_str, ans = unlink (c_str));
  if (ans != 0)
    SCM_SYSERROR;
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

#ifdef HAVE_MKDIR
SCM_DEFINE (scm_mkdir, "mkdir", 1, 1, 0,
            (SCM path, SCM mode),
	    "Create a new directory named by @var{path}.  If @var{mode} is omitted\n"
	    "then the permissions of the directory file are set using the current\n"
	    "umask.  Otherwise they are set to the decimal value specified with\n"
	    "@var{mode}.  The return value is unspecified.")
#define FUNC_NAME s_scm_mkdir
{
  int rv;
  mode_t mask;

  if (SCM_UNBNDP (mode))
    {
      mask = umask (0);
      umask (mask);
      STRING_SYSCALL (path, c_path, rv = mkdir (c_path, 0777 ^ mask));
    }
  else
    {
      STRING_SYSCALL (path, c_path, rv = mkdir (c_path, scm_to_uint (mode)));
    }
  if (rv != 0)
    SCM_SYSERROR;
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME
#endif /* HAVE_MKDIR */

#ifdef HAVE_RMDIR
SCM_DEFINE (scm_rmdir, "rmdir", 1, 0, 0,
            (SCM path),
	    "Remove the existing directory named by @var{path}.  The directory must\n"
	    "be empty for this to succeed.  The return value is unspecified.")
#define FUNC_NAME s_scm_rmdir
{
  int val;

  STRING_SYSCALL (path, c_path, val = rmdir (c_path));
  if (val != 0)
    SCM_SYSERROR;
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME
#endif

/* {Examining Directories}
 */

scm_t_bits scm_tc16_dir;

SCM_DEFINE (scm_directory_stream_p, "directory-stream?", 1, 0, 0,
            (SCM obj),
	    "Return a boolean indicating whether @var{object} is a directory\n"
	    "stream as returned by @code{opendir}.")
#define FUNC_NAME s_scm_directory_stream_p
{
  return scm_from_bool (SCM_DIRP (obj));
}
#undef FUNC_NAME

SCM_DEFINE (scm_opendir, "opendir", 1, 0, 0,
            (SCM dirname),
	    "Open the directory specified by @var{path} and return a directory\n"
	    "stream.")
#define FUNC_NAME s_scm_opendir
{
  DIR *ds;
  STRING_SYSCALL (dirname, c_dirname, ds = opendir (c_dirname));
  if (ds == NULL)
    SCM_SYSERROR;
  SCM_RETURN_NEWSMOB (scm_tc16_dir | (SCM_DIR_FLAG_OPEN<<16), ds);
}
#undef FUNC_NAME

/* FIXME: The glibc manual has a portability note that readdir_r may not
   null-terminate its return string.  The circumstances outlined for this
   are not clear, nor is it clear what should be done about it.  Lets use
   NAMLEN and worry about what else should be done if/when someone can
   figure it out.  */

SCM_DEFINE (scm_readdir, "readdir", 1, 0, 0,
            (SCM port),
	    "Return (as a string) the next directory entry from the directory stream\n"
	    "@var{stream}.  If there is no remaining entry to be read then the\n"
	    "end of file object is returned.")
#define FUNC_NAME s_scm_readdir
{
  struct dirent_or_dirent64 *rdent;

  SCM_VALIDATE_DIR (1, port);
  if (!SCM_DIR_OPEN_P (port))
    SCM_MISC_ERROR ("Directory ~S is not open.", scm_list_1 (port));

#if HAVE_READDIR_R
  /* As noted in the glibc manual, on various systems (such as Solaris) the
     d_name[] field is only 1 char and you're expected to size the dirent
     buffer for readdir_r based on NAME_MAX.  The SCM_MAX expressions below
     effectively give either sizeof(d_name) or NAME_MAX+1, whichever is
     bigger.

     On solaris 10 there's no NAME_MAX constant, it's necessary to use
     pathconf().  We prefer NAME_MAX though, since it should be a constant
     and will therefore save a system call.  We also prefer it since dirfd()
     is not available everywhere.

     An alternative to dirfd() would be to open() the directory and then use
     fdopendir(), if the latter is available.  That'd let us hold the fd
     somewhere in the smob, or just the dirent size calculated once.  */
  {
    struct dirent_or_dirent64 de; /* just for sizeof */
    DIR    *ds = (DIR *) SCM_SMOB_DATA_1 (port);
    size_t namlen;
#ifdef NAME_MAX
    char   buf [SCM_MAX (sizeof (de),
                         sizeof (de) - sizeof (de.d_name) + NAME_MAX + 1)];
#else
    char   *buf;
    long   name_max = fpathconf (dirfd (ds), _PC_NAME_MAX);
    if (name_max == -1)
      SCM_SYSERROR;
    buf = alloca (SCM_MAX (sizeof (de),
                           sizeof (de) - sizeof (de.d_name) + name_max + 1));
#endif

    errno = 0;
    SCM_SYSCALL (readdir_r_or_readdir64_r (ds, (struct dirent_or_dirent64 *) buf, &rdent));
    if (errno != 0)
      SCM_SYSERROR;
    if (! rdent)
      return SCM_EOF_VAL;

    namlen = NAMLEN (rdent);

    return (rdent ? scm_from_locale_stringn (rdent->d_name, NAMLEN (rdent))
            : SCM_EOF_VAL);
  }
#else
  {
    SCM ret;
    scm_dynwind_begin (0);
    scm_i_dynwind_pthread_mutex_lock (&scm_i_misc_mutex);

    errno = 0;
    SCM_SYSCALL (rdent = readdir_or_readdir64 ((DIR *) SCM_SMOB_DATA_1 (port)));
    if (errno != 0)
      SCM_SYSERROR;

    ret = (rdent ? scm_from_locale_stringn (rdent->d_name, NAMLEN (rdent))
           : SCM_EOF_VAL);

    scm_dynwind_end ();
    return ret;
  }
#endif
}
#undef FUNC_NAME

SCM_DEFINE (scm_rewinddir, "rewinddir", 1, 0, 0,
            (SCM port),
	    "Reset the directory port @var{stream} so that the next call to\n"
	    "@code{readdir} will return the first directory entry.")
#define FUNC_NAME s_scm_rewinddir
{
  SCM_VALIDATE_DIR (1, port);
  if (!SCM_DIR_OPEN_P (port))
    SCM_MISC_ERROR ("Directory ~S is not open.", scm_list_1 (port));

  rewinddir ((DIR *) SCM_SMOB_DATA_1 (port));

  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

SCM_DEFINE (scm_closedir, "closedir", 1, 0, 0,
            (SCM port),
	    "Close the directory stream @var{stream}.\n"
	    "The return value is unspecified.")
#define FUNC_NAME s_scm_closedir
{
  SCM_VALIDATE_DIR (1, port);

  if (SCM_DIR_OPEN_P (port))
    {
      int sts;

      SCM_SYSCALL (sts = closedir ((DIR *) SCM_SMOB_DATA_1 (port)));
      if (sts != 0)
	SCM_SYSERROR;

      SCM_SET_SMOB_DATA_0 (port, scm_tc16_dir);
    }

  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

static int
scm_dir_print (SCM exp, SCM port, scm_print_state *pstate SCM_UNUSED)
{
  scm_puts ("#<", port);
  if (!SCM_DIR_OPEN_P (exp))
    scm_puts ("closed: ", port);
  scm_puts ("directory stream ", port);
  scm_uintprint (SCM_SMOB_DATA_1 (exp), 16, port);
  scm_putc ('>', port);
  return 1;
}

static size_t
scm_dir_free (SCM p)
{
  if (SCM_DIR_OPEN_P (p))
    closedir ((DIR *) SCM_SMOB_DATA_1 (p));
  return 0;
}

/* {Navigating Directories}
 */

SCM_DEFINE (scm_chdir, "chdir", 1, 0, 0,
            (SCM str),
	    "Change the current working directory to @var{path}.\n"
	    "The return value is unspecified.")
#define FUNC_NAME s_scm_chdir
{
  int ans;

  STRING_SYSCALL (str, c_str, ans = chdir (c_str));
  if (ans != 0)
    SCM_SYSERROR;
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

#ifdef HAVE_GETCWD
SCM_DEFINE (scm_getcwd, "getcwd", 0, 0, 0,
            (),
	    "Return the name of the current working directory.")
#define FUNC_NAME s_scm_getcwd
{
  char *rv;
  size_t size = 100;
  char *wd;
  SCM result;

  wd = scm_malloc (size);
  while ((rv = getcwd (wd, size)) == 0 && errno == ERANGE)
    {
      free (wd);
      size *= 2;
      wd = scm_malloc (size);
    }
  if (rv == 0)
    {
      int save_errno = errno;
      free (wd);
      errno = save_errno;
      SCM_SYSERROR;
    }
  result = scm_from_locale_stringn (wd, strlen (wd));
  free (wd);
  return result;
}
#undef FUNC_NAME
#endif /* HAVE_GETCWD */

#ifdef HAVE_SELECT

/* check that element is a port or file descriptor.  if it's a port
   and its buffer is ready for use, add it to the ports_ready list.
   otherwise add its file descriptor to *set.  the type of list can be
   determined from pos: SCM_ARG1 for reads, SCM_ARG2 for writes,
   SCM_ARG3 for excepts.  */
static int
set_element (SELECT_TYPE *set, SCM *ports_ready, SCM element, int pos)
{
  int fd;

  if (scm_is_integer (element))
    {
      fd = scm_to_int (element);
    }
  else
    {
      int use_buf = 0;

      element = SCM_COERCE_OUTPORT (element);
      SCM_ASSERT (SCM_OPFPORTP (element), element, pos, "select");
      if (pos == SCM_ARG1)
	{
	  /* check whether port has buffered input.  */
	  scm_t_port *pt = SCM_PTAB_ENTRY (element);

	  if (pt->read_pos < pt->read_end)
	    use_buf = 1;
	}
      else if (pos == SCM_ARG2)
	{
	  /* check whether port's output buffer has room.  */
	  scm_t_port *pt = SCM_PTAB_ENTRY (element);

	  /* > 1 since writing the last byte in the buffer causes flush.  */
	  if (pt->write_end - pt->write_pos > 1)
	    use_buf = 1;
	}
      fd = use_buf ? -1 : SCM_FPORT_FDES (element);
    }
  if (fd == -1)
    *ports_ready = scm_cons (element, *ports_ready);
  else
    FD_SET (fd, set);
  return fd;
}

/* check list_or_vec, a list or vector of ports or file descriptors,
   adding each member to either the ports_ready list (if it's a port
   with a usable buffer) or to *set.  the kind of list_or_vec can be
   determined from pos: SCM_ARG1 for reads, SCM_ARG2 for writes,
   SCM_ARG3 for excepts.  */
static int
fill_select_type (SELECT_TYPE *set, SCM *ports_ready, SCM list_or_vec, int pos)
{
  int max_fd = 0;

  if (scm_is_simple_vector (list_or_vec))
    {
      int i = SCM_SIMPLE_VECTOR_LENGTH (list_or_vec);

      while (--i >= 0)
	{
	  int fd = set_element (set, ports_ready,
				SCM_SIMPLE_VECTOR_REF (list_or_vec, i), pos);

	  if (fd > max_fd)
	    max_fd = fd;
	}
    }
  else
    {
      while (!SCM_NULL_OR_NIL_P (list_or_vec))
	{
	  int fd = set_element (set, ports_ready, SCM_CAR (list_or_vec), pos);

	  if (fd > max_fd)
	    max_fd = fd;
	  list_or_vec = SCM_CDR (list_or_vec);
	}
    }

  return max_fd;
}

/* if element (a file descriptor or port) appears in *set, cons it to
   list.  return list.  */
static SCM
get_element (SELECT_TYPE *set, SCM element, SCM list)
{
  int fd;

  if (scm_is_integer (element))
    {
      fd = scm_to_int (element);
    }
  else
    {
      fd = SCM_FPORT_FDES (SCM_COERCE_OUTPORT (element));
    }
  if (FD_ISSET (fd, set))
    list = scm_cons (element, list);
  return list;
}

/* construct component of scm_select return value.
   set: pointer to set of file descriptors found by select to be ready
   ports_ready: ports ready due to buffering
   list_or_vec: original list/vector handed to scm_select.
   the return value is a list/vector of ready ports/file descriptors.
   works by finding the objects in list which correspond to members of
   *set and appending them to ports_ready.  result is converted to a
   vector if list_or_vec is a vector.  */
static SCM
retrieve_select_type (SELECT_TYPE *set, SCM ports_ready, SCM list_or_vec)
{
  SCM answer_list = ports_ready;

  if (scm_is_simple_vector (list_or_vec))
    {
      int i = SCM_SIMPLE_VECTOR_LENGTH (list_or_vec);

      while (--i >= 0)
	{
	  answer_list = get_element (set,
				     SCM_SIMPLE_VECTOR_REF (list_or_vec, i),
				     answer_list);
	}
      return scm_vector (answer_list);
    }
  else
    {
      /* list_or_vec must be a list.  */
      while (!SCM_NULL_OR_NIL_P (list_or_vec))
	{
	  answer_list = get_element (set, SCM_CAR (list_or_vec), answer_list);
	  list_or_vec = SCM_CDR (list_or_vec);
	}
      return answer_list;
    }
}

/* Static helper functions above refer to s_scm_select directly as s_select */
SCM_DEFINE (scm_select, "select", 3, 2, 0,
            (SCM reads, SCM writes, SCM excepts, SCM secs, SCM usecs),
	    "This procedure has a variety of uses: waiting for the ability\n"
	    "to provide input, accept output, or the existence of\n"
	    "exceptional conditions on a collection of ports or file\n"
	    "descriptors, or waiting for a timeout to occur.\n"
	    "It also returns if interrupted by a signal.\n\n"
	    "@var{reads}, @var{writes} and @var{excepts} can be lists or\n"
	    "vectors, with each member a port or a file descriptor.\n"
	    "The value returned is a list of three corresponding\n"
	    "lists or vectors containing only the members which meet the\n"
	    "specified requirement.  The ability of port buffers to\n"
	    "provide input or accept output is taken into account.\n"
	    "Ordering of the input lists or vectors is not preserved.\n\n"
	    "The optional arguments @var{secs} and @var{usecs} specify the\n"
	    "timeout.  Either @var{secs} can be specified alone, as\n"
	    "either an integer or a real number, or both @var{secs} and\n"
	    "@var{usecs} can be specified as integers, in which case\n"
	    "@var{usecs} is an additional timeout expressed in\n"
	    "microseconds.  If @var{secs} is omitted or is @code{#f} then\n"
	    "select will wait for as long as it takes for one of the other\n"
	    "conditions to be satisfied.\n\n"
	    "The scsh version of @code{select} differs as follows:\n"
	    "Only vectors are accepted for the first three arguments.\n"
	    "The @var{usecs} argument is not supported.\n"
	    "Multiple values are returned instead of a list.\n"
	    "Duplicates in the input vectors appear only once in output.\n"
	    "An additional @code{select!} interface is provided.")
#define FUNC_NAME s_scm_select
{
  struct timeval timeout;
  struct timeval * time_ptr;
  SELECT_TYPE read_set;
  SELECT_TYPE write_set;
  SELECT_TYPE except_set;
  int read_count;
  int write_count;
  int except_count;
  /* these lists accumulate ports which are ready due to buffering.
     their file descriptors don't need to be added to the select sets.  */
  SCM read_ports_ready = SCM_EOL;
  SCM write_ports_ready = SCM_EOL;
  int max_fd;

  if (scm_is_simple_vector (reads))
    {
      read_count = SCM_SIMPLE_VECTOR_LENGTH (reads);
    }
  else
    {
      read_count = scm_ilength (reads);
      SCM_ASSERT (read_count >= 0, reads, SCM_ARG1, FUNC_NAME);
    }
  if (scm_is_simple_vector (writes))
    {
      write_count = SCM_SIMPLE_VECTOR_LENGTH (writes);
    }
  else
    {
      write_count = scm_ilength (writes);
      SCM_ASSERT (write_count >= 0, writes, SCM_ARG2, FUNC_NAME);
    }
  if (scm_is_simple_vector (excepts))
    {
      except_count = SCM_SIMPLE_VECTOR_LENGTH (excepts);
    }
  else
    {
      except_count = scm_ilength (excepts);
      SCM_ASSERT (except_count >= 0, excepts, SCM_ARG3, FUNC_NAME);
    }

  FD_ZERO (&read_set);
  FD_ZERO (&write_set);
  FD_ZERO (&except_set);

  max_fd = fill_select_type (&read_set, &read_ports_ready, reads, SCM_ARG1);

  {
    int write_max = fill_select_type (&write_set, &write_ports_ready,
				      writes, SCM_ARG2);
    int except_max = fill_select_type (&except_set, NULL,
				       excepts, SCM_ARG3);

    if (write_max > max_fd)
      max_fd = write_max;
    if (except_max > max_fd)
      max_fd = except_max;
  }

  /* if there's a port with a ready buffer, don't block, just
     check for ready file descriptors.  */
  if (!scm_is_null (read_ports_ready) || !scm_is_null (write_ports_ready))
    {
      timeout.tv_sec = 0;
      timeout.tv_usec = 0;
      time_ptr = &timeout;
    }
  else if (SCM_UNBNDP (secs) || scm_is_false (secs))
    time_ptr = 0;
  else
    {
      if (scm_is_unsigned_integer (secs, 0, ULONG_MAX))
	{
	  timeout.tv_sec = scm_to_ulong (secs);
	  if (SCM_UNBNDP (usecs))
	    timeout.tv_usec = 0;
	  else
	    timeout.tv_usec = scm_to_long (usecs);
	}
      else
	{
	  double fl = scm_to_double (secs);

	  if (!SCM_UNBNDP (usecs))
	    SCM_WRONG_TYPE_ARG (4, secs);
	  if (fl > LONG_MAX)
	    SCM_OUT_OF_RANGE (4, secs);
	  timeout.tv_sec = (long) fl;
	  timeout.tv_usec = (long) ((fl - timeout.tv_sec) * 1000000);
	}
      time_ptr = &timeout;
    }

  {
    int rv = scm_std_select (max_fd + 1,
			     &read_set, &write_set, &except_set,
			     time_ptr);
    if (rv < 0)
      SCM_SYSERROR;
  }
  return scm_list_3 (retrieve_select_type (&read_set, read_ports_ready, reads),
		     retrieve_select_type (&write_set, write_ports_ready, writes),
		     retrieve_select_type (&except_set, SCM_EOL, excepts));
}
#undef FUNC_NAME
#endif /* HAVE_SELECT */

#ifdef HAVE_FCNTL
SCM_DEFINE (scm_fcntl, "fcntl", 2, 1, 0,
            (SCM object, SCM cmd, SCM value),
	    "Apply @var{command} to the specified file descriptor or the underlying\n"
	    "file descriptor of the specified port.  @var{value} is an optional\n"
	    "integer argument.\n\n"
	    "Values for @var{command} are:\n\n"
	    "@table @code\n"
	    "@item F_DUPFD\n"
	    "Duplicate a file descriptor\n"
	    "@item F_GETFD\n"
	    "Get flags associated with the file descriptor.\n"
	    "@item F_SETFD\n"
	    "Set flags associated with the file descriptor to @var{value}.\n"
	    "@item F_GETFL\n"
	    "Get flags associated with the open file.\n"
	    "@item F_SETFL\n"
	    "Set flags associated with the open file to @var{value}\n"
	    "@item F_GETOWN\n"
	    "Get the process ID of a socket's owner, for @code{SIGIO} signals.\n"
	    "@item F_SETOWN\n"
	    "Set the process that owns a socket to @var{value}, for @code{SIGIO} signals.\n"
	    "@item FD_CLOEXEC\n"
	    "The value used to indicate the \"close on exec\" flag with @code{F_GETFL} or\n"
	    "@code{F_SETFL}.\n"
	    "@end table")
#define FUNC_NAME s_scm_fcntl
{
  int rv;
  int fdes;
  int ivalue;

  object = SCM_COERCE_OUTPORT (object);

  if (SCM_OPFPORTP (object))
    fdes = SCM_FPORT_FDES (object);
  else
    fdes = scm_to_int (object);

  if (SCM_UNBNDP (value))
    ivalue = 0;
  else
    ivalue = scm_to_int (value);

  SCM_SYSCALL (rv = fcntl (fdes, scm_to_int (cmd), ivalue));
  if (rv == -1)
    SCM_SYSERROR;
  return scm_from_int (rv);
}
#undef FUNC_NAME
#endif /* HAVE_FCNTL */

SCM_DEFINE (scm_fsync, "fsync", 1, 0, 0,
            (SCM object),
	    "Copies any unwritten data for the specified output file descriptor to disk.\n"
	    "If @var{port/fd} is a port, its buffer is flushed before the underlying\n"
	    "file descriptor is fsync'd.\n"
	    "The return value is unspecified.")
#define FUNC_NAME s_scm_fsync
{
  int fdes;

  object = SCM_COERCE_OUTPORT (object);

  if (SCM_OPFPORTP (object))
    {
      scm_flush (object);
      fdes = SCM_FPORT_FDES (object);
    }
  else
    fdes = scm_to_int (object);

  if (fsync (fdes) == -1)
    SCM_SYSERROR;
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

#ifdef HAVE_SYMLINK
SCM_DEFINE (scm_symlink, "symlink", 2, 0, 0,
            (SCM oldpath, SCM newpath),
	    "Create a symbolic link named @var{path-to} with the value (i.e., pointing to)\n"
	    "@var{path-from}.  The return value is unspecified.")
#define FUNC_NAME s_scm_symlink
{
  int val;

  STRING2_SYSCALL (oldpath, c_oldpath,
		   newpath, c_newpath,
		   val = symlink (c_oldpath, c_newpath));
  if (val != 0)
    SCM_SYSERROR;
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME
#endif /* HAVE_SYMLINK */

#ifdef HAVE_READLINK
SCM_DEFINE (scm_readlink, "readlink", 1, 0, 0,
            (SCM path),
	    "Return the value of the symbolic link named by @var{path} (a\n"
	    "string), i.e., the file that the link points to.")
#define FUNC_NAME s_scm_readlink
{
  int rv;
  int size = 100;
  char *buf;
  SCM result;
  char *c_path;

  scm_dynwind_begin (0);

  c_path = scm_to_locale_string (path);
  scm_dynwind_free (c_path);

  buf = scm_malloc (size);

  while ((rv = readlink (c_path, buf, size)) == size)
    {
      free (buf);
      size *= 2;
      buf = scm_malloc (size);
    }
  if (rv == -1)
    {
      int save_errno = errno;
      free (buf);
      errno = save_errno;
      SCM_SYSERROR;
    }
  result = scm_take_locale_stringn (buf, rv);

  scm_dynwind_end ();
  return result;
}
#undef FUNC_NAME
#endif /* HAVE_READLINK */

#ifdef HAVE_LSTAT
SCM_DEFINE (scm_lstat, "lstat", 1, 0, 0,
            (SCM str),
	    "Similar to @code{stat}, but does not follow symbolic links, i.e.,\n"
	    "it will return information about a symbolic link itself, not the\n"
	    "file it points to.  @var{path} must be a string.")
#define FUNC_NAME s_scm_lstat
{
  int rv;
  struct stat_or_stat64 stat_temp;

  STRING_SYSCALL (str, c_str, rv = lstat_or_lstat64 (c_str, &stat_temp));
  if (rv != 0)
    {
      int en = errno;

      SCM_SYSERROR_MSG ("~A: ~S",
			scm_list_2 (scm_strerror (scm_from_int (en)), str),
			en);
    }
  return scm_stat2scm (&stat_temp);
}
#undef FUNC_NAME
#endif /* HAVE_LSTAT */

SCM_DEFINE (scm_copy_file, "copy-file", 2, 0, 0,
            (SCM oldfile, SCM newfile),
	    "Copy the file specified by @var{path-from} to @var{path-to}.\n"
	    "The return value is unspecified.")
#define FUNC_NAME s_scm_copy_file
{
  char *c_oldfile, *c_newfile;
  int oldfd, newfd;
  int n, rv;
  char buf[BUFSIZ];
  struct stat_or_stat64 oldstat;

  scm_dynwind_begin (0);

  c_oldfile = scm_to_locale_string (oldfile);
  scm_dynwind_free (c_oldfile);
  c_newfile = scm_to_locale_string (newfile);
  scm_dynwind_free (c_newfile);

  oldfd = open_or_open64 (c_oldfile, O_RDONLY);
  if (oldfd == -1)
    SCM_SYSERROR;

#ifdef __MINGW32__
  SCM_SYSCALL (rv = fstat_Win32 (oldfd, &oldstat));
#else
  SCM_SYSCALL (rv = fstat_or_fstat64 (oldfd, &oldstat));
#endif
  if (rv == -1)
    goto err_close_oldfd;

  /* use POSIX flags instead of 07777?.  */
  newfd = open_or_open64 (c_newfile, O_WRONLY | O_CREAT | O_TRUNC,
                          oldstat.st_mode & 07777);
  if (newfd == -1)
    {
    err_close_oldfd:
      close (oldfd);
      SCM_SYSERROR;
    }

  while ((n = read (oldfd, buf, sizeof buf)) > 0)
    if (write (newfd, buf, n) != n)
      {
	close (oldfd);
	close (newfd);
	SCM_SYSERROR;
      }
  close (oldfd);
  if (close (newfd) == -1)
    SCM_SYSERROR;

  scm_dynwind_end ();
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

/* Filename manipulation */

SCM scm_dot_string;

SCM_DEFINE (scm_dirname, "dirname", 1, 0, 0,
            (SCM filename),
	    "Return the directory name component of the file name\n"
	    "@var{filename}. If @var{filename} does not contain a directory\n"
	    "component, @code{.} is returned.")
#define FUNC_NAME s_scm_dirname
{
  long int i;
  unsigned long int len;

  SCM_VALIDATE_STRING (1, filename);

  len = scm_i_string_length (filename);

  i = len - 1;
#ifdef __MINGW32__
  while (i >= 0 && (scm_i_string_ref (filename, i) == '/'
		    || scm_i_string_ref (filename, i) == '\\'))
    --i;
  while (i >= 0 && (scm_i_string_ref (filename, i) != '/'
		    && scm_i_string_ref (filename, i) != '\\'))
    --i;
  while (i >= 0 && (scm_i_string_ref (filename, i) == '/'
		    || scm_i_string_ref (filename, i) == '\\'))
    --i;
#else
  while (i >= 0 && scm_i_string_ref (filename, i) == '/')
    --i;
  while (i >= 0 && scm_i_string_ref (filename, i) != '/')
    --i;
  while (i >= 0 && scm_i_string_ref (filename, i) == '/')
    --i;
#endif /* ndef __MINGW32__ */
  if (i < 0)
    {
#ifdef __MINGW32__
      if (len > 0 && (scm_i_string_ref (filename, 0) == '/'
		      || scm_i_string_ref (filename, 0) == '\\'))
#else
      if (len > 0 && scm_i_string_ref (filename, 0) == '/')
#endif /* ndef __MINGW32__ */
	return scm_c_substring (filename, 0, 1);
      else
	return scm_dot_string;
    }
  else
    return scm_c_substring (filename, 0, i + 1);
}
#undef FUNC_NAME

SCM_DEFINE (scm_basename, "basename", 1, 1, 0,
            (SCM filename, SCM suffix),
	    "Return the base name of the file name @var{filename}. The\n"
	    "base name is the file name without any directory components.\n"
	    "If @var{suffix} is provided, and is equal to the end of\n"
	    "@var{basename}, it is removed also.")
#define FUNC_NAME s_scm_basename
{
  int i, j, len, end;

  SCM_VALIDATE_STRING (1, filename);
  len = scm_i_string_length (filename);

  if (SCM_UNBNDP (suffix))
    j = -1;
  else
    {
      SCM_VALIDATE_STRING (2, suffix);
      j = scm_i_string_length (suffix) - 1;
    }
  i = len - 1;
#ifdef __MINGW32__
  while (i >= 0 && (scm_i_string_ref (filename, i) == '/'
		    || scm_i_string_ref (filename, i) ==  '\\'))
    --i;
#else
  while (i >= 0 && scm_i_string_ref (filename, i) == '/')
    --i;
#endif /* ndef __MINGW32__ */
  end = i;
  while (i >= 0 && j >= 0
	 && (scm_i_string_ref (filename, i)
	     == scm_i_string_ref (suffix, j)))
    {
      --i;
      --j;
    }
  if (j == -1)
    end = i;
#ifdef __MINGW32__
  while (i >= 0 && (scm_i_string_ref (filename, i) != '/'
		    && scm_i_string_ref (filename, i) != '\\'))
    --i;
#else
  while (i >= 0 && scm_i_string_ref (filename, i) != '/')
    --i;
#endif /* ndef __MINGW32__ */
  if (i == end)
    {
#ifdef __MINGW32__
      if (len > 0 && (scm_i_string_ref (filename, 0) ==  '/'
		      || scm_i_string_ref (filename, 0) ==  '\\'))
#else
      if (len > 0 && scm_i_string_ref (filename, 0) == '/')
#endif /* ndef __MINGW32__ */
        return scm_c_substring (filename, 0, 1);
      else
	return scm_dot_string;
    }
  else
    return scm_c_substring (filename, i+1, end+1);
}
#undef FUNC_NAME

SCM_DEFINE (scm_canonicalize_path, "canonicalize-path", 1, 0, 0,
            (SCM path),
	    "Return the canonical path of @var{path}. A canonical path has\n"
            "no @code{.} or @code{..} components, nor any repeated path\n"
            "separators (@code{/}) nor symlinks.\n\n"
            "Raises an error if any component of @var{path} does not exist.")
#define FUNC_NAME s_scm_canonicalize_path
{
  char *str, *canon;

  SCM_VALIDATE_STRING (1, path);

  str = scm_to_locale_string (path);
  canon = canonicalize_file_name (str);
  free (str);

  if (canon)
    return scm_take_locale_string (canon);
  else
    SCM_SYSERROR;
}
#undef FUNC_NAME

SCM
scm_i_relativize_path (SCM path, SCM in_path)
{
  char *str, *canon;
  SCM scanon;

  str = scm_to_locale_string (path);
  canon = canonicalize_file_name (str);
  free (str);

  if (!canon)
    return SCM_BOOL_F;

  scanon = scm_take_locale_string (canon);

  for (; scm_is_pair (in_path); in_path = scm_cdr (in_path))
    if (scm_is_true (scm_string_prefix_p (scm_car (in_path),
                                          scanon,
                                          SCM_UNDEFINED, SCM_UNDEFINED,
                                          SCM_UNDEFINED, SCM_UNDEFINED)))
      {
        size_t len = scm_c_string_length (scm_car (in_path));

        /* The path either has a trailing delimiter or doesn't. scanon will be
           delimited by single delimiters. In the case in which the path does
           not have a trailing delimiter, add one to the length to strip off the
           delimiter within scanon. */
        if (!len
#ifdef __MINGW32__
            || (scm_i_string_ref (scm_car (in_path), len - 1) != '/'
                && scm_i_string_ref (scm_car (in_path), len - 1) != '\\')
#else
            || scm_i_string_ref (scm_car (in_path), len - 1) != '/'
#endif
            )
          len++;

        if (scm_c_string_length (scanon) > len)
          return scm_substring (scanon, scm_from_size_t (len), SCM_UNDEFINED);
        else
          return SCM_BOOL_F;
      }

  return SCM_BOOL_F;
}

void
scm_init_filesys ()
{
  scm_tc16_dir = scm_make_smob_type ("directory", 0);
  scm_set_smob_free (scm_tc16_dir, scm_dir_free);
  scm_set_smob_print (scm_tc16_dir, scm_dir_print);

  scm_dot_string = scm_from_locale_string (".");

#ifdef O_RDONLY
  scm_c_define ("O_RDONLY", scm_from_int (O_RDONLY));
#endif
#ifdef O_WRONLY
  scm_c_define ("O_WRONLY", scm_from_int (O_WRONLY));
#endif
#ifdef O_RDWR
  scm_c_define ("O_RDWR", scm_from_int (O_RDWR));
#endif
#ifdef O_CREAT
  scm_c_define ("O_CREAT", scm_from_int (O_CREAT));
#endif
#ifdef O_EXCL
  scm_c_define ("O_EXCL", scm_from_int (O_EXCL));
#endif
#ifdef O_NOCTTY
  scm_c_define ("O_NOCTTY", scm_from_int (O_NOCTTY));
#endif
#ifdef O_TRUNC
  scm_c_define ("O_TRUNC", scm_from_int (O_TRUNC));
#endif
#ifdef O_APPEND
  scm_c_define ("O_APPEND", scm_from_int (O_APPEND));
#endif
#ifdef O_NONBLOCK
  scm_c_define ("O_NONBLOCK", scm_from_int (O_NONBLOCK));
#endif
#ifdef O_NDELAY
  scm_c_define ("O_NDELAY", scm_from_int (O_NDELAY));
#endif
#ifdef O_SYNC
  scm_c_define ("O_SYNC", scm_from_int (O_SYNC));
#endif
#ifdef O_LARGEFILE
  scm_c_define ("O_LARGEFILE", scm_from_int (O_LARGEFILE));
#endif

#ifdef F_DUPFD
  scm_c_define ("F_DUPFD", scm_from_int (F_DUPFD));
#endif
#ifdef F_GETFD
  scm_c_define ("F_GETFD", scm_from_int (F_GETFD));
#endif
#ifdef F_SETFD
  scm_c_define ("F_SETFD", scm_from_int (F_SETFD));
#endif
#ifdef F_GETFL
  scm_c_define ("F_GETFL", scm_from_int (F_GETFL));
#endif
#ifdef F_SETFL
  scm_c_define ("F_SETFL", scm_from_int (F_SETFL));
#endif
#ifdef F_GETOWN
  scm_c_define ("F_GETOWN", scm_from_int (F_GETOWN));
#endif
#ifdef F_SETOWN
  scm_c_define ("F_SETOWN", scm_from_int (F_SETOWN));
#endif
#ifdef FD_CLOEXEC
  scm_c_define ("FD_CLOEXEC", scm_from_int (FD_CLOEXEC));
#endif

#include "libguile/filesys.x"
}

/*
  Local Variables:
  c-file-style: "gnu"
  End:
*/


code:
/* classes: h_files */

#ifndef SCM_FILESYS_H
#define SCM_FILESYS_H

/* Copyright (C) 1995,1997,1998,1999,2000,2001, 2006, 2008, 2009, 2010 Free Software Foundation, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 3 of
 * the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

#include "libguile/__scm.h"

SCM_API scm_t_bits scm_tc16_dir;

#define SCM_DIR_FLAG_OPEN (1L << 0)

#define SCM_DIRP(x) (!SCM_IMP (x) && (SCM_TYP16 (x) == scm_tc16_dir))
#define SCM_DIR_OPEN_P(x) (SCM_SMOB_FLAGS (x) & SCM_DIR_FLAG_OPEN)

SCM_API SCM scm_chown (SCM object, SCM owner, SCM group);
SCM_API SCM scm_chmod (SCM object, SCM mode);
SCM_API SCM scm_umask (SCM mode);
SCM_API SCM scm_open_fdes (SCM path, SCM flags, SCM mode);
SCM_API SCM scm_open (SCM path, SCM flags, SCM mode);
SCM_API SCM scm_close (SCM fd_or_port);
SCM_API SCM scm_close_fdes (SCM fd);
SCM_API SCM scm_stat (SCM object, SCM exception_on_error);
SCM_API SCM scm_link (SCM oldpath, SCM newpath);
SCM_API SCM scm_rename (SCM oldname, SCM newname);
SCM_API SCM scm_delete_file (SCM str);
SCM_API SCM scm_mkdir (SCM path, SCM mode);
SCM_API SCM scm_rmdir (SCM path);
SCM_API SCM scm_directory_stream_p (SCM obj);
SCM_API SCM scm_opendir (SCM dirname);
SCM_API SCM scm_readdir (SCM port);
SCM_API SCM scm_rewinddir (SCM port);
SCM_API SCM scm_closedir (SCM port);
SCM_API SCM scm_chdir (SCM str);
SCM_API SCM scm_getcwd (void);
SCM_API SCM scm_select (SCM reads, SCM writes, SCM excepts, SCM secs, SCM msecs);
SCM_API SCM scm_fcntl (SCM object, SCM cmd, SCM value);
SCM_API SCM scm_fsync (SCM object);
SCM_API SCM scm_symlink (SCM oldpath, SCM newpath);
SCM_API SCM scm_readlink (SCM path);
SCM_API SCM scm_lstat (SCM str);
SCM_API SCM scm_copy_file (SCM oldfile, SCM newfile);
SCM_API SCM scm_dirname (SCM filename);
SCM_API SCM scm_basename (SCM filename, SCM suffix);
SCM_API SCM scm_canonicalize_path (SCM path);
SCM_INTERNAL SCM scm_i_relativize_path (SCM path, SCM in_path);

SCM_INTERNAL void scm_init_filesys (void);

#endif  /* SCM_FILESYS_H */

/*
  Local Variables:
  c-file-style: "gnu"
  End:
*/

license: mit


code:
/* Copyright (C) 1996,1997,2000,2001, 2004, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 3 of
 * the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

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

#include "libguile/_scm.h"
#include "libguile/print.h"
#include "libguile/dynwind.h"
#include "libguile/fluids.h"
#include "libguile/alist.h"
#include "libguile/eval.h"
#include "libguile/ports.h"
#include "libguile/deprecation.h"
#include "libguile/validate.h"
#include "libguile/bdw-gc.h"

/* Number of additional slots to allocate when ALLOCATED_FLUIDS is full.  */
#define FLUID_GROW 128

/* Vector of allocated fluids indexed by fluid numbers.  Access is protected by
   FLUID_ADMIN_MUTEX.  */
static void **allocated_fluids = NULL;
static size_t allocated_fluids_len = 0;

static scm_i_pthread_mutex_t fluid_admin_mutex = SCM_I_PTHREAD_MUTEX_INITIALIZER;

#define IS_FLUID(x)         SCM_FLUID_P (x)
#define FLUID_NUM(x)        SCM_I_FLUID_NUM (x)

#define IS_DYNAMIC_STATE(x) SCM_I_DYNAMIC_STATE_P (x)
#define DYNAMIC_STATE_FLUIDS(x)        SCM_I_DYNAMIC_STATE_FLUIDS (x)
#define SET_DYNAMIC_STATE_FLUIDS(x, y) SCM_SET_CELL_WORD_1 ((x), (SCM_UNPACK (y)))

/* Grow STATE so that it can hold up to ALLOCATED_FLUIDS_LEN fluids.  This may
   be more than necessary since ALLOCATED_FLUIDS is sparse and the current
   thread may not access all the fluids anyway.  Memory usage could be improved
   by using a 2-level array as is done in glibc for pthread keys (TODO).  */
static void
grow_dynamic_state (SCM state)
{
  SCM new_fluids;
  SCM old_fluids = DYNAMIC_STATE_FLUIDS (state);
  size_t i, len, old_len = SCM_SIMPLE_VECTOR_LENGTH (old_fluids);

  /* Assume the assignment below is atomic.  */
  len = allocated_fluids_len;

  new_fluids = scm_c_make_vector (len, SCM_BOOL_F);

  for (i = 0; i < old_len; i++)
    SCM_SIMPLE_VECTOR_SET (new_fluids, i,
			   SCM_SIMPLE_VECTOR_REF (old_fluids, i));
  SET_DYNAMIC_STATE_FLUIDS (state, new_fluids);
}

void
scm_i_fluid_print (SCM exp, SCM port, scm_print_state *pstate SCM_UNUSED)
{
  scm_puts ("#<fluid ", port);
  scm_intprint ((int) FLUID_NUM (exp), 10, port);
  scm_putc ('>', port);
}

void
scm_i_dynamic_state_print (SCM exp, SCM port, scm_print_state *pstate SCM_UNUSED)
{
  scm_puts ("#<dynamic-state ", port);
  scm_intprint (SCM_UNPACK (exp), 16, port);
  scm_putc ('>', port);
}

void
scm_i_with_fluids_print (SCM exp, SCM port, scm_print_state *pstate SCM_UNUSED)
{
  scm_puts ("#<with-fluids ", port);
  scm_intprint (SCM_UNPACK (exp), 16, port);
  scm_putc ('>', port);
}

/* Return a new fluid.  */
static SCM
new_fluid ()
{
  SCM fluid;
  size_t trial, n;

  /* Fluids are pointerless cells: the first word is the type tag; the second
     word is the fluid number.  */
  fluid = PTR2SCM (scm_gc_malloc_pointerless (sizeof (scm_t_cell), "fluid"));
  SCM_SET_CELL_TYPE (fluid, scm_tc7_fluid);

  scm_dynwind_begin (0);
  scm_i_dynwind_pthread_mutex_lock (&fluid_admin_mutex);

  for (trial = 0; trial < 2; trial++)
    {
      /* Look for a free fluid number.  */
      for (n = 0; n < allocated_fluids_len; n++)
	/* TODO: Use `__sync_bool_compare_and_swap' where available.  */
	if (allocated_fluids[n] == NULL)
	  break;

      if (trial == 0 && n >= allocated_fluids_len)
	/* All fluid numbers are in use.  Run a GC and retry.  Explicitly
	   running the GC is costly and bad-style.  We only do this because
	   dynamic state fluid vectors would grow unreasonably if fluid numbers
	   weren't reused.  */
	scm_i_gc ("fluids");
    }

  if (n >= allocated_fluids_len)
    {
      /* Grow the vector of allocated fluids.  */
      void **new_allocated_fluids =
	scm_gc_malloc_pointerless ((allocated_fluids_len + FLUID_GROW)
				   * sizeof (*allocated_fluids),
				   "allocated fluids");

      /* Copy over old values and initialize rest.  GC can not run
	 during these two operations since there is no safe point in
	 them.  */
      memcpy (new_allocated_fluids, allocated_fluids,
	      allocated_fluids_len * sizeof (*allocated_fluids));
      memset (new_allocated_fluids + allocated_fluids_len, 0,
	      FLUID_GROW * sizeof (*allocated_fluids));
      n = allocated_fluids_len;

      /* Update the vector of allocated fluids.  Dynamic states will
	 eventually be lazily grown to accomodate the new value of
	 ALLOCATED_FLUIDS_LEN in `fluid-ref' and `fluid-set!'.  */
      allocated_fluids = new_allocated_fluids;
      allocated_fluids_len += FLUID_GROW;
    }

  allocated_fluids[n] = SCM2PTR (fluid);
  SCM_SET_CELL_WORD_1 (fluid, (scm_t_bits) n);

  GC_GENERAL_REGISTER_DISAPPEARING_LINK (&allocated_fluids[n],
					 SCM2PTR (fluid));

  scm_dynwind_end ();
  return fluid;
}

SCM_DEFINE (scm_make_fluid, "make-fluid", 0, 0, 0,
	    (),
	    "Return a newly created fluid.\n"
	    "Fluids are objects that can hold one\n"
	    "value per dynamic state.  That is, modifications to this value are\n"
	    "only visible to code that executes with the same dynamic state as\n"
	    "the modifying code.  When a new dynamic state is constructed, it\n"
	    "inherits the values from its parent.  Because each thread normally executes\n"
	    "with its own dynamic state, you can use fluids for thread local storage.")
#define FUNC_NAME s_scm_make_fluid
{
  return new_fluid ();
}
#undef FUNC_NAME

SCM_DEFINE (scm_make_undefined_fluid, "make-undefined-fluid", 0, 0, 0,
            (),
            "")
#define FUNC_NAME s_scm_make_undefined_fluid
{
  SCM f = new_fluid ();
  scm_fluid_set_x (f, SCM_UNDEFINED);
  return f;
}
#undef FUNC_NAME

SCM_DEFINE (scm_fluid_p, "fluid?", 1, 0, 0,
	    (SCM obj),
	    "Return @code{#t} iff @var{obj} is a fluid; otherwise, return\n"
	    "@code{#f}.")
#define FUNC_NAME s_scm_fluid_p
{
  return scm_from_bool (IS_FLUID (obj));
}
#undef FUNC_NAME

int
scm_is_fluid (SCM obj)
{
  return IS_FLUID (obj);
}

/* Does not check type of `fluid'! */
static SCM
fluid_ref (SCM fluid)
{
  SCM fluids = DYNAMIC_STATE_FLUIDS (SCM_I_CURRENT_THREAD->dynamic_state);

  if (SCM_UNLIKELY (FLUID_NUM (fluid) >= SCM_SIMPLE_VECTOR_LENGTH (fluids)))
    {
      /* Lazily grow the current thread's dynamic state.  */
      grow_dynamic_state (SCM_I_CURRENT_THREAD->dynamic_state);

      fluids = DYNAMIC_STATE_FLUIDS (SCM_I_CURRENT_THREAD->dynamic_state);
    }

  return SCM_SIMPLE_VECTOR_REF (fluids, FLUID_NUM (fluid));
}

SCM_DEFINE (scm_fluid_ref, "fluid-ref", 1, 0, 0,
	    (SCM fluid),
	    "Return the value associated with @var{fluid} in the current\n"
	    "dynamic root.  If @var{fluid} has not been set, then return\n"
	    "@code{#f}.")
#define FUNC_NAME s_scm_fluid_ref
{
  SCM val;
  SCM_VALIDATE_FLUID (1, fluid);
  val = fluid_ref (fluid);
  if (SCM_UNBNDP (val))
    SCM_MISC_ERROR ("unbound fluid: ~S",
                    scm_list_1 (fluid));
  return val;
}
#undef FUNC_NAME

SCM_DEFINE (scm_fluid_set_x, "fluid-set!", 2, 0, 0,
	    (SCM fluid, SCM value),
	    "Set the value associated with @var{fluid} in the current dynamic root.")
#define FUNC_NAME s_scm_fluid_set_x
{
  SCM fluids = DYNAMIC_STATE_FLUIDS (SCM_I_CURRENT_THREAD->dynamic_state);

  SCM_VALIDATE_FLUID (1, fluid);

  if (SCM_UNLIKELY (FLUID_NUM (fluid) >= SCM_SIMPLE_VECTOR_LENGTH (fluids)))
    {
      /* Lazily grow the current thread's dynamic state.  */
      grow_dynamic_state (SCM_I_CURRENT_THREAD->dynamic_state);

      fluids = DYNAMIC_STATE_FLUIDS (SCM_I_CURRENT_THREAD->dynamic_state);
    }

  SCM_SIMPLE_VECTOR_SET (fluids, FLUID_NUM (fluid), value);
  return SCM_UNSPECIFIED;
}
#undef FUNC_NAME

SCM_DEFINE (scm_fluid_unset_x, "fluid-unset!", 1, 0, 0,
            (SCM fluid),
            "Unset the value associated with @var{fluid}.")
#define FUNC_NAME s_scm_fluid_unset_x
{
  return scm_fluid_set_x (fluid, SCM_UNDEFINED);
}
#undef FUNC_NAME

SCM_DEFINE (scm_fluid_bound_p, "fluid-bound?", 1, 0, 0,
	    (SCM fluid),
	    "Return @code{#t} iff @var{fluid} is bound to a value.\n"
	    "Throw an error if @var{fluid} is not a fluid.")
#define FUNC_NAME s_scm_fluid_bound_p
{
  SCM val;
  SCM_VALIDATE_FLUID (1, fluid);
  val = fluid_ref (fluid);
  return scm_from_bool (! (SCM_UNBNDP (val)));
}
#undef FUNC_NAME

static SCM
apply_thunk (void *thunk)
{
  return scm_call_0 (SCM_PACK (thunk));
}

SCM
scm_i_make_with_fluids (size_t n, SCM *fluids, SCM *vals)
{
  SCM ret;

  /* Ensure that there are no duplicates in the fluids set -- an N^2 operation,
     but N will usually be small, so perhaps that's OK. */
  {
    size_t i, j = n;

    while (j--)
      for (i = 0; i < j; i++)
        if (fluids[i] == fluids[j])
          {
            vals[i] = vals[j]; /* later bindings win */
            n--;
            break;
          }
  }

  ret = scm_words (scm_tc7_with_fluids | (n << 8), 1 + n*2);
  SCM_SET_CELL_WORD_1 (ret, n);

  while (n--)
    {
      if (SCM_UNLIKELY (!IS_FLUID (fluids[n])))
        scm_wrong_type_arg ("with-fluids", 0, fluids[n]);
      SCM_SET_CELL_OBJECT (ret, 1 + n * 2, fluids[n]);
      SCM_SET_CELL_OBJECT (ret, 2 + n * 2, vals[n]);
    }

  return ret;
}

void
scm_i_swap_with_fluids (SCM wf, SCM dynstate)
{
  SCM fluids;
  size_t i, max = 0;

  fluids = DYNAMIC_STATE_FLUIDS (dynstate);

  /* We could cache the max in the with-fluids, but that would take more mem,
     and we're touching all the fluids anyway, so this per-swap traversal should
     be OK. */
  for (i = 0; i < SCM_WITH_FLUIDS_LEN (wf); i++)
    {
      size_t num = FLUID_NUM (SCM_WITH_FLUIDS_NTH_FLUID (wf, i));
      max = (max > num) ? max : num;
    }

  if (SCM_UNLIKELY (max >= SCM_SIMPLE_VECTOR_LENGTH (fluids)))
    {
      /* Lazily grow the current thread's dynamic state.  */
      grow_dynamic_state (dynstate);

      fluids = DYNAMIC_STATE_FLUIDS (dynstate);
    }

  /* Bind the fluids. Order doesn't matter, as all fluids are distinct. */
  for (i = 0; i < SCM_WITH_FLUIDS_LEN (wf); i++)
    {
      size_t fluid_num;
      SCM x;

      fluid_num = FLUID_NUM (SCM_WITH_FLUIDS_NTH_FLUID (wf, i));
      x = SCM_SIMPLE_VECTOR_REF (fluids, fluid_num);
      SCM_SIMPLE_VECTOR_SET (fluids, fluid_num,
                             SCM_WITH_FLUIDS_NTH_VAL (wf, i));
      SCM_WITH_FLUIDS_SET_NTH_VAL (wf, i, x);
    }
}

SCM_DEFINE (scm_with_fluids, "with-fluids*", 3, 0, 0,
	    (SCM fluids, SCM values, SCM thunk),
	    "Set @var{fluids} to @var{values} temporary, and call @var{thunk}.\n"
	    "@var{fluids} must be a list of fluids and @var{values} must be the same\n"
	    "number of their values to be applied.  Each substitution is done\n"
	    "one after another.  @var{thunk} must be a procedure with no argument.")
#define FUNC_NAME s_scm_with_fluids
{
  return scm_c_with_fluids (fluids, values,
			    apply_thunk, (void *) SCM_UNPACK (thunk));
}
#undef FUNC_NAME

SCM
scm_c_with_fluids (SCM fluids, SCM values, SCM (*cproc) (), void *cdata)
#define FUNC_NAME "scm_c_with_fluids"
{
  SCM wf, ans;
  long flen, vlen, i;
  SCM *fluidsv, *valuesv;

  SCM_VALIDATE_LIST_COPYLEN (1, fluids, flen);
  SCM_VALIDATE_LIST_COPYLEN (2, values, vlen);
  if (flen != vlen)
    scm_out_of_range (s_scm_with_fluids, values);

  if (SCM_UNLIKELY (flen == 0))
    return cproc (cdata);

  fluidsv = alloca (sizeof(SCM)*flen);
  valuesv = alloca (sizeof(SCM)*flen);

  for (i = 0; i < flen; i++)
    {
      fluidsv[i] = SCM_CAR (fluids);
      fluids = SCM_CDR (fluids);
      valuesv[i] = SCM_CAR (values);
      values = SCM_CDR (values);
    }

  wf = scm_i_make_with_fluids (flen, fluidsv, valuesv);
  scm_i_swap_with_fluids (wf, SCM_I_CURRENT_THREAD->dynamic_state);
  scm_i_set_dynwinds (scm_cons (wf, scm_i_dynwinds ()));
  ans = cproc (cdata);
  scm_i_swap_with_fluids (wf, SCM_I_CURRENT_THREAD->dynamic_state);
  scm_i_set_dynwinds (scm_cdr (scm_i_dynwinds ()));

  return ans;
}
#undef FUNC_NAME

SCM_DEFINE (scm_with_fluid, "with-fluid*", 3, 0, 0,
	    (SCM fluid, SCM value, SCM thunk),
	    "Set @var{fluid} to @var{value} temporarily, and call @var{thunk}.\n"
	    "@var{thunk} must be a procedure with no argument.")
#define FUNC_NAME s_scm_with_fluid
{
  return scm_c_with_fluid (fluid, value,
			   apply_thunk, (void *) SCM_UNPACK (thunk));
}
#undef FUNC_NAME

SCM
scm_c_with_fluid (SCM fluid, SCM value, SCM (*cproc) (), void *cdata)
#define FUNC_NAME "scm_c_with_fluid"
{
  SCM ans, wf;

  wf = scm_i_make_with_fluids (1, &fluid, &value);
  scm_i_swap_with_fluids (wf, SCM_I_CURRENT_THREAD->dynamic_state);
  scm_i_set_dynwinds (scm_cons (wf, scm_i_dynwinds ()));
  ans = cproc (cdata);
  scm_i_swap_with_fluids (wf, SCM_I_CURRENT_THREAD->dynamic_state);
  scm_i_set_dynwinds (scm_cdr (scm_i_dynwinds ()));

  return ans;
}
#undef FUNC_NAME

static void
swap_fluid (SCM data)
{
  SCM f = SCM_CAR (data);
  SCM t = fluid_ref (f);
  scm_fluid_set_x (f, SCM_CDR (data));
  SCM_SETCDR (data, t);
}

void
scm_dynwind_fluid (SCM fluid, SCM value)
{
  SCM data = scm_cons (fluid, value);
  scm_dynwind_rewind_handler_with_scm (swap_fluid, data, SCM_F_WIND_EXPLICITLY);
  scm_dynwind_unwind_handler_with_scm (swap_fluid, data, SCM_F_WIND_EXPLICITLY);
}

SCM
scm_i_make_initial_dynamic_state ()
{
  SCM fluids = scm_c_make_vector (allocated_fluids_len, SCM_BOOL_F);
  return scm_cell (scm_tc7_dynamic_state, SCM_UNPACK (fluids));
}

SCM_DEFINE (scm_make_dynamic_state, "make-dynamic-state", 0, 1, 0,
	    (SCM parent),
	    "Return a copy of the dynamic state object @var{parent}\n"
	    "or of the current dynamic state when @var{parent} is omitted.")
#define FUNC_NAME s_scm_make_dynamic_state
{
  SCM fluids;

  if (SCM_UNBNDP (parent))
    parent = scm_current_dynamic_state ();

  SCM_ASSERT (IS_DYNAMIC_STATE (parent), parent, SCM_ARG1, FUNC_NAME);
  fluids = scm_vector_copy (DYNAMIC_STATE_FLUIDS (parent));
  return scm_cell (scm_tc7_dynamic_state, SCM_UNPACK (fluids));
}
#undef FUNC_NAME

SCM_DEFINE (scm_dynamic_state_p, "dynamic-state?", 1, 0, 0,
	    (SCM obj),
	    "Return @code{#t} if @var{obj} is a dynamic state object;\n"
	    "return @code{#f} otherwise")
#define FUNC_NAME s_scm_dynamic_state_p
{
  return scm_from_bool (IS_DYNAMIC_STATE (obj));
}
#undef FUNC_NAME

int
scm_is_dynamic_state (SCM obj)
{
  return IS_DYNAMIC_STATE (obj);
}

SCM_DEFINE (scm_current_dynamic_state, "current-dynamic-state", 0, 0, 0,
	    (),
	    "Return the current dynamic state object.")
#define FUNC_NAME s_scm_current_dynamic_state
{
  return SCM_I_CURRENT_THREAD->dynamic_state;
}
#undef FUNC_NAME

SCM_DEFINE (scm_set_current_dynamic_state, "set-current-dynamic-state", 1,0,0,
	    (SCM state),
	    "Set the current dynamic state object to @var{state}\n"
	    "and return the previous current dynamic state object.")
#define FUNC_NAME s_scm_set_current_dynamic_state
{
  scm_i_thread *t = SCM_I_CURRENT_THREAD;
  SCM old = t->dynamic_state;
  SCM_ASSERT (IS_DYNAMIC_STATE (state), state, SCM_ARG1, FUNC_NAME);
  t->dynamic_state = state;
  return old;
}
#undef FUNC_NAME

static void
swap_dynamic_state (SCM loc)
{
  SCM_SETCAR (loc, scm_set_current_dynamic_state (SCM_CAR (loc)));
}

void
scm_dynwind_current_dynamic_state (SCM state)
{
  SCM loc = scm_cons (state, SCM_EOL);
  SCM_ASSERT (IS_DYNAMIC_STATE (state), state, SCM_ARG1, NULL);
  scm_dynwind_rewind_handler_with_scm (swap_dynamic_state, loc,
				     SCM_F_WIND_EXPLICITLY);
  scm_dynwind_unwind_handler_with_scm (swap_dynamic_state, loc,
				     SCM_F_WIND_EXPLICITLY);
}

void *
scm_c_with_dynamic_state (SCM state, void *(*func)(void *), void *data)
{
  void *result;
  scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE);
  scm_dynwind_current_dynamic_state (state);
  result = func (data);
  scm_dynwind_end ();
  return result;
}

SCM_DEFINE (scm_with_dynamic_state, "with-dynamic-state", 2, 0, 0,
	    (SCM state, SCM proc),
	    "Call @var{proc} while @var{state} is the current dynamic\n"
	    "state object.")
#define FUNC_NAME s_scm_with_dynamic_state
{
  SCM result;
  scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE);
  scm_dynwind_current_dynamic_state (state);
  result = scm_call_0 (proc);
  scm_dynwind_end ();
  return result;
}
#undef FUNC_NAME

void
scm_init_fluids ()
{
#include "libguile/fluids.x"
}

/*
  Local Variables:
  c-file-style: "gnu"
  End:
*/


code:
/* classes: h_files */

#ifndef SCM_FLUIDS_H
#define SCM_FLUIDS_H

/* Copyright (C) 1996,2000,2001, 2006, 2008, 2009, 2010 Free Software Foundation, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 3 of
 * the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

#include "libguile/__scm.h"
#include "libguile/root.h"
#include "libguile/vectors.h"

/* These "with-fluids" objects live on the dynamic stack, and record previous
   values of fluids. Guile uses shallow binding, so the current fluid values are
   always in the same place for a given thread, in the dynamic-state vector.
 */

#define SCM_WITH_FLUIDS_P(x) (!SCM_IMP (x) && SCM_TYP7(x) == scm_tc7_with_fluids)
#define SCM_WITH_FLUIDS_LEN(x) (SCM_CELL_WORD ((x), 0) >> 8)
#define SCM_WITH_FLUIDS_NTH_FLUID(x,n) (SCM_CELL_OBJECT ((x), 1 + (n)*2))
#define SCM_WITH_FLUIDS_NTH_VAL(x,n) (SCM_CELL_OBJECT ((x), 2 + (n)*2))
#define SCM_WITH_FLUIDS_SET_NTH_VAL(x,n,v) (SCM_SET_CELL_OBJECT ((x), 2 + (n)*2, (v)))

/* Fluids.

   Fluids are objects of a certain type that can hold one SCM value per
   dynamic state. That is, modifications to this value are only visible
   to code that executes with the same dynamic state as the modifying
   code. When a new dynamic state is constructed, it inherits the
   values from its parent. Because each thread executes with its own
   dynamic state, you can use fluids for thread local storage.

   Each fluid is identified by a small integer. This integer is used to
   index a vector that holds the values of all fluids. A dynamic state
   consists of this vector, wrapped in an object so that the vector can
   grow.
 */

#define SCM_FLUID_P(x)          (!SCM_IMP (x) && SCM_TYP7 (x) == scm_tc7_fluid)
#ifdef BUILDING_LIBGUILE
#define SCM_I_FLUID_NUM(x)        ((size_t)SCM_CELL_WORD_1(x))
#endif

SCM_API SCM scm_make_fluid (void);
SCM_API SCM scm_make_undefined_fluid (void);
SCM_API int scm_is_fluid (SCM obj);
SCM_API SCM scm_fluid_p (SCM fl);
SCM_API SCM scm_fluid_ref (SCM fluid);
SCM_API SCM scm_fluid_set_x (SCM fluid, SCM value);
SCM_API SCM scm_fluid_unset_x (SCM fluid);
SCM_API SCM scm_fluid_bound_p (SCM fluid);

SCM_INTERNAL SCM scm_i_make_with_fluids (size_t n, SCM *fluids, SCM *vals);
SCM_INTERNAL void scm_i_swap_with_fluids (SCM with_fluids, SCM dynamic_state);

SCM_API SCM scm_c_with_fluids (SCM fluids, SCM vals,
			       SCM (*cproc)(void *), void *cdata);
SCM_API SCM scm_c_with_fluid (SCM fluid, SCM val,
			      SCM (*cproc)(void *), void *cdata);
SCM_API SCM scm_with_fluids (SCM fluids, SCM vals, SCM thunk);
SCM_API SCM scm_with_fluid (SCM fluid, SCM val, SCM thunk);

SCM_API void scm_dynwind_fluid (SCM fluid, SCM value);

#ifdef BUILDING_LIBGUILE
#define SCM_I_DYNAMIC_STATE_P(x) (!SCM_IMP (x) && SCM_TYP7 (x) == scm_tc7_dynamic_state)
#define SCM_I_DYNAMIC_STATE_FLUIDS(x)        SCM_PACK (SCM_CELL_WORD_1 (x))
#endif

SCM_API SCM scm_make_dynamic_state (SCM parent);
SCM_API SCM scm_dynamic_state_p (SCM obj);
SCM_API int scm_is_dynamic_state (SCM obj);
SCM_API SCM scm_current_dynamic_state (void);
SCM_API SCM scm_set_current_dynamic_state (SCM state);
SCM_API void scm_dynwind_current_dynamic_state (SCM state);
SCM_API void *scm_c_with_dynamic_state (SCM state,
					void *(*func)(void *), void *data);
SCM_API SCM scm_with_dynamic_state (SCM state, SCM proc);

SCM_INTERNAL SCM scm_i_make_initial_dynamic_state (void);

SCM_INTERNAL void scm_i_fluid_print (SCM exp, SCM port, scm_print_state *pstate);
SCM_INTERNAL void scm_i_dynamic_state_print (SCM exp, SCM port, scm_print_state *pstate);
SCM_INTERNAL void scm_i_with_fluids_print (SCM exp, SCM port, scm_print_state *pstate);
SCM_INTERNAL void scm_init_fluids (void);

#endif  /* SCM_FLUIDS_H */

/*
  Local Variables:
  c-file-style: "gnu"
  End:
*/