/* GLIB - Library of useful routines for C programming

 * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald

 *

 * giounix.c: IO Channels using unix file descriptors

 * Copyright 1998 Owen Taylor

 *

 * SPDX-License-Identifier: LGPL-2.1-or-later

 *

 * 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 2.1 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, see <http://www.gnu.org/licenses/>.

 */

/*

 * Modified by the GLib Team and others 1997-2000.  See the AUTHORS

 * file for a list of people on the GLib Team.  See the ChangeLog

 * files for a list of changes.  These files are distributed with

 * GLib at ftp://ftp.gtk.org/pub/gtk/.

 */

/*

 * MT safe

 */

#include "config.h"

#define _POSIX_SOURCE   /* for SSIZE_MAX */

#include <sys/types.h>

#include <sys/stat.h>

#include <stdio.h>

#include <unistd.h>

#include <errno.h>

#include <string.h>

#include <fcntl.h>

#include <glib/gstdio.h>

#ifndef O_CLOEXEC

#define O_CLOEXEC 0

#endif

#include "giochannel.h"

#include "gerror.h"

#include "gfileutils.h"

#include "gstrfuncs.h"

#include "gtestutils.h"

/*

 * Unix IO Channels

 */

typedef struct _GIOUnixChannel GIOUnixChannel;

typedef struct _GIOUnixWatch GIOUnixWatch;

struct _GIOUnixChannel

{

  GIOChannel channel;

  gint fd;

};

struct _GIOUnixWatch

{

  GSource       source;

  GPollFD       pollfd;

  GIOChannel   *channel;

  GIOCondition  condition;

};

static GIOStatus  g_io_unix_read    (GIOChannel   *channel,

             gchar        *buf,

             gsize         count,

             gsize        *bytes_read,

             GError      **err);

static GIOStatus  g_io_unix_write   (GIOChannel   *channel,

             const gchar  *buf,

             gsize         count,

             gsize        *bytes_written,

             GError      **err);

static GIOStatus  g_io_unix_seek    (GIOChannel   *channel,

             gint64        offset,

             GSeekType     type,

             GError      **err);

static GIOStatus  g_io_unix_close   (GIOChannel   *channel,

             GError      **err);

static void   g_io_unix_free    (GIOChannel   *channel);

static GSource*   g_io_unix_create_watch  (GIOChannel   *channel,

             GIOCondition  condition);

static GIOStatus  g_io_unix_set_flags (GIOChannel   *channel,

                               GIOFlags      flags,

             GError      **err);

static GIOFlags   g_io_unix_get_flags (GIOChannel   *channel);

static gboolean g_io_unix_prepare  (GSource     *source,

            gint        *timeout);

static gboolean g_io_unix_check    (GSource     *source);

static gboolean g_io_unix_dispatch (GSource     *source,

            GSourceFunc  callback,

            gpointer     user_data);

static void     g_io_unix_finalize (GSource     *source);

GSourceFuncs g_io_watch_funcs = {

  g_io_unix_prepare,

  g_io_unix_check,

  g_io_unix_dispatch,

  g_io_unix_finalize,

  NULL, NULL

};

static GIOFuncs unix_channel_funcs = {

  g_io_unix_read,

  g_io_unix_write,

  g_io_unix_seek,

  g_io_unix_close,

  g_io_unix_create_watch,

  g_io_unix_free,

  g_io_unix_set_flags,

  g_io_unix_get_flags,

};

static gboolean 

g_io_unix_prepare (GSource  *source,

       gint     *timeout)

{

  GIOUnixWatch *watch = (GIOUnixWatch *)source;

  GIOCondition buffer_condition = g_io_channel_get_buffer_condition (watch->channel);

  /* Only return TRUE here if _all_ bits in watch->condition will be set

   */

  return ((watch->condition & buffer_condition) == watch->condition);

}

static gboolean 

g_io_unix_check (GSource  *source)

{

  GIOUnixWatch *watch = (GIOUnixWatch *)source;

  GIOCondition buffer_condition = g_io_channel_get_buffer_condition (watch->channel);

  GIOCondition poll_condition = watch->pollfd.revents;

  return ((poll_condition | buffer_condition) & watch->condition);

}

static gboolean

g_io_unix_dispatch (GSource     *source,

        GSourceFunc  callback,

        gpointer     user_data)

{

  GIOFunc func = (GIOFunc)callback;

  GIOUnixWatch *watch = (GIOUnixWatch *)source;

  GIOCondition buffer_condition = g_io_channel_get_buffer_condition (watch->channel);

  if (!func)

    {

      g_warning ("IO watch dispatched without callback. "

     "You must call g_source_connect().");

      return FALSE;

    }

  return (*func) (watch->channel,

      (watch->pollfd.revents | buffer_condition) & watch->condition,

      user_data);

}

static void 

g_io_unix_finalize (GSource *source)

{

  GIOUnixWatch *watch = (GIOUnixWatch *)source;

  g_io_channel_unref (watch->channel);

}

static GIOStatus

g_io_unix_read (GIOChannel *channel, 

    gchar      *buf, 

    gsize       count,

    gsize      *bytes_read,

    GError    **err)

{

  GIOUnixChannel *unix_channel = (GIOUnixChannel *)channel;

  gssize result;

  if (count > SSIZE_MAX) /* At least according to the Debian manpage for read */

    count = SSIZE_MAX;

 retry:

  result = read (unix_channel->fd, buf, count);

  if (result < 0)

    {

      int errsv = errno;

      *bytes_read = 0;

      switch (errsv)

        {

#ifdef EINTR

          case EINTR:

            goto retry;

#endif

#ifdef EAGAIN

          case EAGAIN:

            return G_IO_STATUS_AGAIN;

#endif

          default:

            g_set_error_literal (err, G_IO_CHANNEL_ERROR,

                                 g_io_channel_error_from_errno (errsv),

                                 g_strerror (errsv));

            return G_IO_STATUS_ERROR;

        }

    }

  *bytes_read = result;

  return (result > 0) ? G_IO_STATUS_NORMAL : G_IO_STATUS_EOF;

}

static GIOStatus

g_io_unix_write (GIOChannel  *channel, 

     const gchar *buf, 

     gsize       count,

     gsize      *bytes_written,

     GError    **err)

{

  GIOUnixChannel *unix_channel = (GIOUnixChannel *)channel;

  gssize result;

 retry:

  result = write (unix_channel->fd, buf, count);

  if (result < 0)

    {

      int errsv = errno;

      *bytes_written = 0;

      switch (errsv)

        {

#ifdef EINTR

          case EINTR:

            goto retry;

#endif

#ifdef EAGAIN

          case EAGAIN:

            return G_IO_STATUS_AGAIN;

#endif

          default:

            g_set_error_literal (err, G_IO_CHANNEL_ERROR,

                                 g_io_channel_error_from_errno (errsv),

                                 g_strerror (errsv));

            return G_IO_STATUS_ERROR;

        }

    }

  *bytes_written = result;

  return G_IO_STATUS_NORMAL;

}

static GIOStatus

g_io_unix_seek (GIOChannel *channel,

    gint64      offset, 

    GSeekType   type,

                GError    **err)

{

  GIOUnixChannel *unix_channel = (GIOUnixChannel *)channel;

  int whence;

  off_t tmp_offset;

  off_t result;

  switch (type)

    {

    case G_SEEK_SET:

      whence = SEEK_SET;

      break;

    case G_SEEK_CUR:

      whence = SEEK_CUR;

      break;

    case G_SEEK_END:

      whence = SEEK_END;

      break;

    default:

      whence = -1; /* Shut the compiler up */

      g_assert_not_reached ();

    }

  tmp_offset = offset;

  if (tmp_offset != offset)

    {

      g_set_error_literal (err, G_IO_CHANNEL_ERROR,

                           g_io_channel_error_from_errno (EINVAL),

                           g_strerror (EINVAL));

      return G_IO_STATUS_ERROR;

    }

  result = lseek (unix_channel->fd, tmp_offset, whence);

  if (result < 0)

    {

      int errsv = errno;

      g_set_error_literal (err, G_IO_CHANNEL_ERROR,

                           g_io_channel_error_from_errno (errsv),

                           g_strerror (errsv));

      return G_IO_STATUS_ERROR;

    }

  return G_IO_STATUS_NORMAL;

}

static GIOStatus

g_io_unix_close (GIOChannel *channel,

     GError    **err)

{

  GIOUnixChannel *unix_channel = (GIOUnixChannel *)channel;

  if (close (unix_channel->fd) < 0)

    {

      int errsv = errno;

      g_set_error_literal (err, G_IO_CHANNEL_ERROR,

                           g_io_channel_error_from_errno (errsv),

                           g_strerror (errsv));

      return G_IO_STATUS_ERROR;

    }

  return G_IO_STATUS_NORMAL;

}

static void 

g_io_unix_free (GIOChannel *channel)

{

  GIOUnixChannel *unix_channel = (GIOUnixChannel *)channel;

  g_free (unix_channel);

}

static GSource *

g_io_unix_create_watch (GIOChannel   *channel,

      GIOCondition  condition)

{

  GIOUnixChannel *unix_channel = (GIOUnixChannel *)channel;

  GSource *source;

  GIOUnixWatch *watch;

  source = g_source_new (&g_io_watch_funcs, sizeof (GIOUnixWatch));

  g_source_set_static_name (source, "GIOChannel (Unix)");

  watch = (GIOUnixWatch *)source;

  watch->channel = channel;

  g_io_channel_ref (channel);

  watch->condition = condition;

  watch->pollfd.fd = unix_channel->fd;

  watch->pollfd.events = condition;

  g_source_add_poll (source, &watch->pollfd);

  return source;

}

static GIOStatus

g_io_unix_set_flags (GIOChannel *channel,

                     GIOFlags    flags,

                     GError    **err)

{

  glong fcntl_flags;

  GIOUnixChannel *unix_channel = (GIOUnixChannel *) channel;

  fcntl_flags = 0;

  if (flags & G_IO_FLAG_APPEND)

    fcntl_flags |= O_APPEND;

  if (flags & G_IO_FLAG_NONBLOCK)

#ifdef O_NONBLOCK

    fcntl_flags |= O_NONBLOCK;

#else

    fcntl_flags |= O_NDELAY;

#endif

  if (fcntl (unix_channel->fd, F_SETFL, fcntl_flags) == -1)

    {

      int errsv = errno;

      g_set_error_literal (err, G_IO_CHANNEL_ERROR,

                           g_io_channel_error_from_errno (errsv),

                           g_strerror (errsv));

      return G_IO_STATUS_ERROR;

    }

  return G_IO_STATUS_NORMAL;

}

static GIOFlags

g_io_unix_get_flags (GIOChannel *channel)

{

  GIOFlags flags = G_IO_FLAG_NONE;

  glong fcntl_flags;

  GIOUnixChannel *unix_channel = (GIOUnixChannel *) channel;

  fcntl_flags = fcntl (unix_channel->fd, F_GETFL);

  if (fcntl_flags == -1)

    {

      int err = errno;

      g_warning (G_STRLOC "Error while getting flags for FD: %s (%d)",

     g_strerror (err), err);

      return 0;

    }

  if (fcntl_flags & O_APPEND)

    flags |= G_IO_FLAG_APPEND;

#ifdef O_NONBLOCK

  if (fcntl_flags & O_NONBLOCK)

#else

  if (fcntl_flags & O_NDELAY)

#endif

    flags |= G_IO_FLAG_NONBLOCK;

  switch (fcntl_flags & (O_RDONLY | O_WRONLY | O_RDWR))

    {

      case O_RDONLY:

        channel->is_readable = TRUE;

        channel->is_writeable = FALSE;

        break;

      case O_WRONLY:

        channel->is_readable = FALSE;

        channel->is_writeable = TRUE;

        break;

      case O_RDWR:

        channel->is_readable = TRUE;

        channel->is_writeable = TRUE;

        break;

      default:

        g_assert_not_reached ();

    }

  return flags;

}

GIOChannel *

g_io_channel_new_file (const gchar *filename,

                       const gchar *mode,

                       GError     **error)

{

  int fid, flags;

  mode_t create_mode;

  GIOChannel *channel;

  enum { /* Cheesy hack */

    MODE_R = 1 << 0,

    MODE_W = 1 << 1,

    MODE_A = 1 << 2,

    MODE_PLUS = 1 << 3,

    MODE_R_PLUS = MODE_R | MODE_PLUS,

    MODE_W_PLUS = MODE_W | MODE_PLUS,

    MODE_A_PLUS = MODE_A | MODE_PLUS

  } mode_num;

  struct stat buffer;

  g_return_val_if_fail (filename != NULL, NULL);

  g_return_val_if_fail (mode != NULL, NULL);

  g_return_val_if_fail ((error == NULL) || (*error == NULL), NULL);

  switch (mode[0])

    {

      case 'r':

        mode_num = MODE_R;

        break;

      case 'w':

        mode_num = MODE_W;

        break;

      case 'a':

        mode_num = MODE_A;

        break;

      default:

        g_warning ("Invalid GIOFileMode %s.", mode);

        return NULL;

    }

  switch (mode[1])

    {

      case '\0':

        break;

      case '+':

        if (mode[2] == '\0')

          {

            mode_num |= MODE_PLUS;

            break;

          }

        G_GNUC_FALLTHROUGH;

      default:

        g_warning ("Invalid GIOFileMode %s.", mode);

        return NULL;

    }

  switch (mode_num)

    {

      case MODE_R:

        flags = O_RDONLY;

        break;

      case MODE_W:

        flags = O_WRONLY | O_TRUNC | O_CREAT;

        break;

      case MODE_A:

        flags = O_WRONLY | O_APPEND | O_CREAT;

        break;

      case MODE_R_PLUS:

        flags = O_RDWR;

        break;

      case MODE_W_PLUS:

        flags = O_RDWR | O_TRUNC | O_CREAT;

        break;

      case MODE_A_PLUS:

        flags = O_RDWR | O_APPEND | O_CREAT;

        break;

      case MODE_PLUS:

      default:

        g_assert_not_reached ();

        flags = 0;

    }

  create_mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;

  fid = g_open (filename, flags | O_CLOEXEC, create_mode);

  if (fid == -1)

    {

      int err = errno;

      g_set_error_literal (error, G_FILE_ERROR,

                           g_file_error_from_errno (err),

                           g_strerror (err));

      return (GIOChannel *)NULL;

    }

  if (fstat (fid, &buffer) == -1) /* In case someone opens a FIFO */

    {

      int err = errno;

      close (fid);

      g_set_error_literal (error, G_FILE_ERROR,

                           g_file_error_from_errno (err),

                           g_strerror (err));

      return (GIOChannel *)NULL;

    }

  channel = (GIOChannel *) g_new (GIOUnixChannel, 1);

  channel->is_seekable = S_ISREG (buffer.st_mode) || S_ISCHR (buffer.st_mode)

                         || S_ISBLK (buffer.st_mode);

  switch (mode_num)

    {

      case MODE_R:

        channel->is_readable = TRUE;

        channel->is_writeable = FALSE;

        break;

      case MODE_W:

      case MODE_A:

        channel->is_readable = FALSE;

        channel->is_writeable = TRUE;

        break;

      case MODE_R_PLUS:

      case MODE_W_PLUS:

      case MODE_A_PLUS:

        channel->is_readable = TRUE;

        channel->is_writeable = TRUE;

        break;

      case MODE_PLUS:

      default:

        g_assert_not_reached ();

    }

  g_io_channel_init (channel);

  channel->close_on_unref = TRUE; /* must be after g_io_channel_init () */

  channel->funcs = &unix_channel_funcs;

  ((GIOUnixChannel *) channel)->fd = fid;

  return channel;

}

/**

 * g_io_channel_unix_new:

 * @fd: a file descriptor.

 *

 * Creates a new #GIOChannel given a file descriptor. On UNIX systems

 * this works for plain files, pipes, and sockets.

 *

 * The returned #GIOChannel has a reference count of 1.

 *

 * The default encoding for #GIOChannel is UTF-8. If your application

 * is reading output from a command using via pipe, you may need to set

 * the encoding to the encoding of the current locale (see

 * g_get_charset()) with the g_io_channel_set_encoding() function.

 * By default, the fd passed will not be closed when the final reference

 * to the #GIOChannel data structure is dropped.

 *

 * If you want to read raw binary data without interpretation, then

 * call the g_io_channel_set_encoding() function with %NULL for the

 * encoding argument.

 *

 * This function is available in GLib on Windows, too, but you should

 * avoid using it on Windows. The domain of file descriptors and

 * sockets overlap. There is no way for GLib to know which one you mean

 * in case the argument you pass to this function happens to be both a

 * valid file descriptor and socket. If that happens a warning is

 * issued, and GLib assumes that it is the file descriptor you mean.

 *

 * Returns: a new #GIOChannel.

 **/

GIOChannel *

g_io_channel_unix_new (gint fd)

{

  struct stat buffer;

  GIOUnixChannel *unix_channel = g_new (GIOUnixChannel, 1);

  GIOChannel *channel = (GIOChannel *)unix_channel;

  g_io_channel_init (channel);

  channel->funcs = &unix_channel_funcs;

  unix_channel->fd = fd;

  /* I'm not sure if fstat on a non-file (e.g., socket) works

   * it should be safe to say if it fails, the fd isn't seekable.

   */

  /* Newer UNIX versions support S_ISSOCK(), fstat() will probably

   * succeed in most cases.

   */

  if (fstat (unix_channel->fd, &buffer) == 0)

    channel->is_seekable = S_ISREG (buffer.st_mode) || S_ISCHR (buffer.st_mode)

                           || S_ISBLK (buffer.st_mode);

  else /* Assume not seekable */

    channel->is_seekable = FALSE;

  g_io_unix_get_flags (channel); /* Sets is_readable, is_writeable */

  return channel;

}

/**

 * g_io_channel_unix_get_fd:

 * @channel: a #GIOChannel, created with g_io_channel_unix_new().

 *

 * Returns the file descriptor of the #GIOChannel.

 *

 * On Windows this function returns the file descriptor or socket of

 * the #GIOChannel.

 *

 * Returns: the file descriptor of the #GIOChannel.

 **/

gint

g_io_channel_unix_get_fd (GIOChannel *channel)

{

  GIOUnixChannel *unix_channel = (GIOUnixChannel *)channel;

  return unix_channel->fd;

}