gstreamer/plugins/elements/gstfdsink.c
Sebastian Dröge c15f1b2bec fdsink/filesink: Refactor writev() code to prevent stack overflows
If buffer lists with too many buffers would be written before, a stack
overflow would happen because of memory linear with the number of
GstMemory would be allocated on the stack. This could happen for example
when filesink is configured with a very big buffer size.

Instead now move the buffer and buffer list writing into the helper
functions and at most write IOV_MAX memories at once. Anything bigger
than that wouldn't be passed to writev() anyway and written differently
in the previous code, so this also potentially speeds up writing for
these cases.

For example the following pipeline would crash with a stackoverflow:
gst-launch-1.0 audiotestsrc ! filesink buffer-size=1073741824 location=/dev/null
2020-03-26 11:31:03 +00:00

641 lines
16 KiB
C

/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
*
* gstfdsink.c:
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:element-fdsink
* @title: fdsink
* @see_also: #GstFdSrc
*
* Write data to a unix file descriptor.
*
* This element will synchronize on the clock before writing the data on the
* socket. For file descriptors where this does not make sense (files, ...) the
* #GstBaseSink:sync property can be used to disable synchronisation.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include "../../gst/gst-i18n-lib.h"
#include <sys/types.h>
#include <sys/stat.h>
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#include <fcntl.h>
#include <stdio.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef _MSC_VER
#undef stat
#define stat _stat
#define fstat _fstat
#define S_ISREG(m) (((m)&S_IFREG)==S_IFREG)
#endif
#include <errno.h>
#include <string.h>
#include "gstfdsink.h"
#include "gstelements_private.h"
#ifdef G_OS_WIN32
#include <io.h> /* lseek, open, close, read */
#undef lseek
#define lseek _lseeki64
#undef off_t
#define off_t guint64
#endif
#define struct_stat struct stat
#if defined(__BIONIC__) /* Android */
#if defined(__ANDROID_API__) && __ANDROID_API__ >= 21
#undef fstat
#define fstat fstat64
#undef struct_stat
#define struct_stat struct stat64
#endif
#endif
static GstStaticPadTemplate sinktemplate = GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS_ANY);
GST_DEBUG_CATEGORY_STATIC (gst_fd_sink__debug);
#define GST_CAT_DEFAULT gst_fd_sink__debug
/* FdSink signals and args */
enum
{
/* FILL ME */
LAST_SIGNAL
};
enum
{
ARG_0,
ARG_FD
};
static void gst_fd_sink_uri_handler_init (gpointer g_iface,
gpointer iface_data);
#define _do_init \
G_IMPLEMENT_INTERFACE (GST_TYPE_URI_HANDLER, gst_fd_sink_uri_handler_init); \
GST_DEBUG_CATEGORY_INIT (gst_fd_sink__debug, "fdsink", 0, "fdsink element");
#define gst_fd_sink_parent_class parent_class
G_DEFINE_TYPE_WITH_CODE (GstFdSink, gst_fd_sink, GST_TYPE_BASE_SINK, _do_init);
static void gst_fd_sink_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_fd_sink_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static void gst_fd_sink_dispose (GObject * obj);
static gboolean gst_fd_sink_query (GstBaseSink * bsink, GstQuery * query);
static GstFlowReturn gst_fd_sink_render (GstBaseSink * sink,
GstBuffer * buffer);
static GstFlowReturn gst_fd_sink_render_list (GstBaseSink * bsink,
GstBufferList * buffer_list);
static gboolean gst_fd_sink_start (GstBaseSink * basesink);
static gboolean gst_fd_sink_stop (GstBaseSink * basesink);
static gboolean gst_fd_sink_unlock (GstBaseSink * basesink);
static gboolean gst_fd_sink_unlock_stop (GstBaseSink * basesink);
static gboolean gst_fd_sink_event (GstBaseSink * sink, GstEvent * event);
static gboolean gst_fd_sink_do_seek (GstFdSink * fdsink, guint64 new_offset);
static void
gst_fd_sink_class_init (GstFdSinkClass * klass)
{
GObjectClass *gobject_class;
GstElementClass *gstelement_class;
GstBaseSinkClass *gstbasesink_class;
gobject_class = G_OBJECT_CLASS (klass);
gstelement_class = GST_ELEMENT_CLASS (klass);
gstbasesink_class = GST_BASE_SINK_CLASS (klass);
gobject_class->set_property = gst_fd_sink_set_property;
gobject_class->get_property = gst_fd_sink_get_property;
gobject_class->dispose = gst_fd_sink_dispose;
gst_element_class_set_static_metadata (gstelement_class,
"Filedescriptor Sink",
"Sink/File",
"Write data to a file descriptor", "Erik Walthinsen <omega@cse.ogi.edu>");
gst_element_class_add_static_pad_template (gstelement_class, &sinktemplate);
gstbasesink_class->render = GST_DEBUG_FUNCPTR (gst_fd_sink_render);
gstbasesink_class->render_list = GST_DEBUG_FUNCPTR (gst_fd_sink_render_list);
gstbasesink_class->start = GST_DEBUG_FUNCPTR (gst_fd_sink_start);
gstbasesink_class->stop = GST_DEBUG_FUNCPTR (gst_fd_sink_stop);
gstbasesink_class->unlock = GST_DEBUG_FUNCPTR (gst_fd_sink_unlock);
gstbasesink_class->unlock_stop = GST_DEBUG_FUNCPTR (gst_fd_sink_unlock_stop);
gstbasesink_class->event = GST_DEBUG_FUNCPTR (gst_fd_sink_event);
gstbasesink_class->query = GST_DEBUG_FUNCPTR (gst_fd_sink_query);
g_object_class_install_property (gobject_class, ARG_FD,
g_param_spec_int ("fd", "fd", "An open file descriptor to write to",
0, G_MAXINT, 1, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
}
static void
gst_fd_sink_init (GstFdSink * fdsink)
{
fdsink->fd = 1;
fdsink->uri = g_strdup_printf ("fd://%d", fdsink->fd);
fdsink->bytes_written = 0;
fdsink->current_pos = 0;
gst_base_sink_set_sync (GST_BASE_SINK (fdsink), FALSE);
}
static void
gst_fd_sink_dispose (GObject * obj)
{
GstFdSink *fdsink = GST_FD_SINK (obj);
g_free (fdsink->uri);
fdsink->uri = NULL;
G_OBJECT_CLASS (parent_class)->dispose (obj);
}
static gboolean
gst_fd_sink_query (GstBaseSink * bsink, GstQuery * query)
{
gboolean res = FALSE;
GstFdSink *fdsink;
fdsink = GST_FD_SINK (bsink);
switch (GST_QUERY_TYPE (query)) {
case GST_QUERY_POSITION:
{
GstFormat format;
gst_query_parse_position (query, &format, NULL);
switch (format) {
case GST_FORMAT_DEFAULT:
case GST_FORMAT_BYTES:
gst_query_set_position (query, GST_FORMAT_BYTES, fdsink->current_pos);
res = TRUE;
break;
default:
break;
}
break;
}
case GST_QUERY_FORMATS:
gst_query_set_formats (query, 2, GST_FORMAT_DEFAULT, GST_FORMAT_BYTES);
res = TRUE;
break;
case GST_QUERY_URI:
gst_query_set_uri (query, fdsink->uri);
res = TRUE;
break;
case GST_QUERY_SEEKING:{
GstFormat format;
gst_query_parse_seeking (query, &format, NULL, NULL, NULL);
if (format == GST_FORMAT_BYTES || format == GST_FORMAT_DEFAULT) {
gst_query_set_seeking (query, GST_FORMAT_BYTES, fdsink->seekable, 0,
-1);
} else {
gst_query_set_seeking (query, format, FALSE, 0, -1);
}
res = TRUE;
break;
}
default:
res = GST_BASE_SINK_CLASS (parent_class)->query (bsink, query);
break;
}
return res;
}
static GstFlowReturn
gst_fd_sink_render_list (GstBaseSink * bsink, GstBufferList * buffer_list)
{
GstFdSink *sink;
GstFlowReturn ret;
guint64 skip = 0;
guint num_buffers;
sink = GST_FD_SINK_CAST (bsink);
num_buffers = gst_buffer_list_length (buffer_list);
if (num_buffers == 0)
goto no_data;
for (;;) {
guint64 bytes_written = 0;
ret = gst_writev_buffer_list (GST_OBJECT_CAST (sink), sink->fd, sink->fdset,
buffer_list, &bytes_written, skip, 0, -1, NULL);
sink->bytes_written += bytes_written;
sink->current_pos += bytes_written;
skip += bytes_written;
if (!sink->unlock)
break;
ret = gst_base_sink_wait_preroll (GST_BASE_SINK (sink));
if (ret != GST_FLOW_OK)
return ret;
}
return ret;
no_data:
{
GST_LOG_OBJECT (sink, "empty buffer list");
return GST_FLOW_OK;
}
}
static GstFlowReturn
gst_fd_sink_render (GstBaseSink * bsink, GstBuffer * buffer)
{
GstFdSink *sink;
GstFlowReturn ret;
guint64 skip = 0;
sink = GST_FD_SINK_CAST (bsink);
for (;;) {
guint64 bytes_written = 0;
ret = gst_writev_buffer (GST_OBJECT_CAST (sink), sink->fd, sink->fdset,
buffer, &bytes_written, skip, 0, -1, NULL);
sink->bytes_written += bytes_written;
sink->current_pos += bytes_written;
skip += bytes_written;
if (!sink->unlock)
break;
ret = gst_base_sink_wait_preroll (GST_BASE_SINK (sink));
if (ret != GST_FLOW_OK)
return ret;
}
return ret;
}
static gboolean
gst_fd_sink_check_fd (GstFdSink * fdsink, int fd, GError ** error)
{
struct_stat stat_results;
off_t result;
/* see that it is a valid file descriptor */
if (fstat (fd, &stat_results) < 0)
goto invalid;
if (!S_ISREG (stat_results.st_mode))
goto not_seekable;
/* see if it is a seekable stream */
result = lseek (fd, 0, SEEK_CUR);
if (result == -1) {
switch (errno) {
case EINVAL:
case EBADF:
goto invalid;
case ESPIPE:
goto not_seekable;
}
} else
GST_DEBUG_OBJECT (fdsink, "File descriptor %d is seekable", fd);
return TRUE;
invalid:
{
GST_ELEMENT_ERROR (fdsink, RESOURCE, WRITE, (NULL),
("File descriptor %d is not valid: %s", fd, g_strerror (errno)));
g_set_error (error, GST_URI_ERROR, GST_URI_ERROR_BAD_REFERENCE,
"File descriptor %d is not valid: %s", fd, g_strerror (errno));
return FALSE;
}
not_seekable:
{
GST_DEBUG_OBJECT (fdsink, "File descriptor %d is a pipe", fd);
return TRUE;
}
}
static gboolean
gst_fd_sink_start (GstBaseSink * basesink)
{
GstFdSink *fdsink;
GstPollFD fd = GST_POLL_FD_INIT;
fdsink = GST_FD_SINK (basesink);
if (!gst_fd_sink_check_fd (fdsink, fdsink->fd, NULL))
return FALSE;
if ((fdsink->fdset = gst_poll_new (TRUE)) == NULL)
goto socket_pair;
fd.fd = fdsink->fd;
gst_poll_add_fd (fdsink->fdset, &fd);
gst_poll_fd_ctl_write (fdsink->fdset, &fd, TRUE);
fdsink->bytes_written = 0;
fdsink->current_pos = 0;
fdsink->seekable = gst_fd_sink_do_seek (fdsink, 0);
GST_INFO_OBJECT (fdsink, "seeking supported: %d", fdsink->seekable);
return TRUE;
/* ERRORS */
socket_pair:
{
GST_ELEMENT_ERROR (fdsink, RESOURCE, OPEN_READ_WRITE, (NULL),
GST_ERROR_SYSTEM);
return FALSE;
}
}
static gboolean
gst_fd_sink_stop (GstBaseSink * basesink)
{
GstFdSink *fdsink = GST_FD_SINK (basesink);
if (fdsink->fdset) {
gst_poll_free (fdsink->fdset);
fdsink->fdset = NULL;
}
return TRUE;
}
static gboolean
gst_fd_sink_unlock (GstBaseSink * basesink)
{
GstFdSink *fdsink = GST_FD_SINK (basesink);
GST_LOG_OBJECT (fdsink, "Flushing");
GST_OBJECT_LOCK (fdsink);
fdsink->unlock = TRUE;
gst_poll_set_flushing (fdsink->fdset, TRUE);
GST_OBJECT_UNLOCK (fdsink);
return TRUE;
}
static gboolean
gst_fd_sink_unlock_stop (GstBaseSink * basesink)
{
GstFdSink *fdsink = GST_FD_SINK (basesink);
GST_LOG_OBJECT (fdsink, "No longer flushing");
GST_OBJECT_LOCK (fdsink);
fdsink->unlock = FALSE;
gst_poll_set_flushing (fdsink->fdset, FALSE);
GST_OBJECT_UNLOCK (fdsink);
return TRUE;
}
static gboolean
gst_fd_sink_update_fd (GstFdSink * fdsink, int new_fd, GError ** error)
{
if (new_fd < 0) {
g_set_error (error, GST_URI_ERROR, GST_URI_ERROR_BAD_REFERENCE,
"File descriptor %d is not valid", new_fd);
return FALSE;
}
if (!gst_fd_sink_check_fd (fdsink, new_fd, error))
goto invalid;
/* assign the fd */
GST_OBJECT_LOCK (fdsink);
if (fdsink->fdset) {
GstPollFD fd = GST_POLL_FD_INIT;
fd.fd = fdsink->fd;
gst_poll_remove_fd (fdsink->fdset, &fd);
fd.fd = new_fd;
gst_poll_add_fd (fdsink->fdset, &fd);
gst_poll_fd_ctl_write (fdsink->fdset, &fd, TRUE);
}
fdsink->fd = new_fd;
g_free (fdsink->uri);
fdsink->uri = g_strdup_printf ("fd://%d", fdsink->fd);
GST_OBJECT_UNLOCK (fdsink);
return TRUE;
invalid:
{
return FALSE;
}
}
static void
gst_fd_sink_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstFdSink *fdsink;
fdsink = GST_FD_SINK (object);
switch (prop_id) {
case ARG_FD:{
int fd;
fd = g_value_get_int (value);
gst_fd_sink_update_fd (fdsink, fd, NULL);
break;
}
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_fd_sink_get_property (GObject * object, guint prop_id, GValue * value,
GParamSpec * pspec)
{
GstFdSink *fdsink;
fdsink = GST_FD_SINK (object);
switch (prop_id) {
case ARG_FD:
g_value_set_int (value, fdsink->fd);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static gboolean
gst_fd_sink_do_seek (GstFdSink * fdsink, guint64 new_offset)
{
off_t result;
result = lseek (fdsink->fd, new_offset, SEEK_SET);
if (result == -1)
goto seek_failed;
fdsink->current_pos = new_offset;
GST_DEBUG_OBJECT (fdsink, "File descriptor %d to seek to position "
"%" G_GUINT64_FORMAT, fdsink->fd, fdsink->current_pos);
return TRUE;
/* ERRORS */
seek_failed:
{
GST_DEBUG_OBJECT (fdsink, "File descriptor %d failed to seek to position "
"%" G_GUINT64_FORMAT, fdsink->fd, new_offset);
return FALSE;
}
}
static gboolean
gst_fd_sink_event (GstBaseSink * sink, GstEvent * event)
{
GstEventType type;
GstFdSink *fdsink;
fdsink = GST_FD_SINK (sink);
type = GST_EVENT_TYPE (event);
switch (type) {
case GST_EVENT_SEGMENT:
{
const GstSegment *segment;
gst_event_parse_segment (event, &segment);
if (segment->format == GST_FORMAT_BYTES) {
/* only try to seek and fail when we are going to a different
* position */
if (fdsink->current_pos != segment->start) {
/* FIXME, the seek should be performed on the pos field, start/stop are
* just boundaries for valid bytes offsets. We should also fill the file
* with zeroes if the new position extends the current EOF (sparse streams
* and segment accumulation). */
if (!gst_fd_sink_do_seek (fdsink, (guint64) segment->start))
goto seek_failed;
}
} else {
GST_DEBUG_OBJECT (fdsink,
"Ignored SEGMENT event of format %u (%s)", (guint) segment->format,
gst_format_get_name (segment->format));
}
break;
}
default:
break;
}
return GST_BASE_SINK_CLASS (parent_class)->event (sink, event);
seek_failed:
{
GST_ELEMENT_ERROR (fdsink, RESOURCE, SEEK, (NULL),
("Error while seeking on file descriptor %d: %s",
fdsink->fd, g_strerror (errno)));
gst_event_unref (event);
return FALSE;
}
}
/*** GSTURIHANDLER INTERFACE *************************************************/
static GstURIType
gst_fd_sink_uri_get_type (GType type)
{
return GST_URI_SINK;
}
static const gchar *const *
gst_fd_sink_uri_get_protocols (GType type)
{
static const gchar *protocols[] = { "fd", NULL };
return protocols;
}
static gchar *
gst_fd_sink_uri_get_uri (GstURIHandler * handler)
{
GstFdSink *sink = GST_FD_SINK (handler);
/* FIXME: make thread-safe */
return g_strdup (sink->uri);
}
static gboolean
gst_fd_sink_uri_set_uri (GstURIHandler * handler, const gchar * uri,
GError ** error)
{
GstFdSink *sink = GST_FD_SINK (handler);
gint fd;
if (sscanf (uri, "fd://%d", &fd) != 1) {
g_set_error (error, GST_URI_ERROR, GST_URI_ERROR_BAD_URI,
"File descriptor URI could not be parsed");
return FALSE;
}
return gst_fd_sink_update_fd (sink, fd, error);
}
static void
gst_fd_sink_uri_handler_init (gpointer g_iface, gpointer iface_data)
{
GstURIHandlerInterface *iface = (GstURIHandlerInterface *) g_iface;
iface->get_type = gst_fd_sink_uri_get_type;
iface->get_protocols = gst_fd_sink_uri_get_protocols;
iface->get_uri = gst_fd_sink_uri_get_uri;
iface->set_uri = gst_fd_sink_uri_set_uri;
}