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glib2.0/glib/giounix.c

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/* 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;
}
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