GstShmAllocator: New shared memory allocator

This makes Wayland's allocator public. It is generally useful to have a
shared memory allocator that can create memfd on Linux.

Sponsored-by: Netflix Inc.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5328>

subprojects/gst-plugins-bad/ext/gtk/gstgtkwaylandsink.c

@@ -889,7 +889,7 @@ gst_gtk_wayland_activate_shm_pool (GstGtkWaylandSink * self)
     gboolean is_shm = FALSE;
 
     if (gst_buffer_pool_config_get_allocator (config, &alloc, NULL) && alloc)
-      is_shm = GST_IS_WL_SHM_ALLOCATOR (alloc);
+      is_shm = GST_IS_SHM_ALLOCATOR (alloc);
 
     gst_structure_free (config);
 
@@ -897,7 +897,7 @@ gst_gtk_wayland_activate_shm_pool (GstGtkWaylandSink * self)
       return TRUE;
   }
 
-  alloc = gst_wl_shm_allocator_get ();
+  alloc = gst_shm_allocator_get ();
   gst_gtk_wayland_update_pool (self, alloc);
   gst_object_unref (alloc);
 
@@ -1059,7 +1059,7 @@ gst_gtk_wayland_sink_propose_allocation (GstBaseSink * bsink, GstQuery * query)
     gst_buffer_pool_config_set_params (config,
         caps, priv->video_info.size, 2, 0);
     gst_buffer_pool_config_set_allocator (config,
-        gst_wl_shm_allocator_get (), NULL);
+        gst_shm_allocator_get (), NULL);
     gst_buffer_pool_set_config (pool, config);
   }
 
@@ -1067,7 +1067,7 @@ gst_gtk_wayland_sink_propose_allocation (GstBaseSink * bsink, GstQuery * query)
   if (pool)
     g_object_unref (pool);
 
-  alloc = gst_wl_shm_allocator_get ();
+  alloc = gst_shm_allocator_get ();
   gst_query_add_allocation_param (query, alloc, NULL);
   gst_query_add_allocation_meta (query, GST_VIDEO_META_API_TYPE, NULL);
   g_object_unref (alloc);

subprojects/gst-plugins-bad/ext/wayland/gstwaylandsink.c

@@ -637,7 +637,7 @@ gst_wayland_activate_shm_pool (GstWaylandSink * self)
     gboolean is_shm = FALSE;
 
     if (gst_buffer_pool_config_get_allocator (config, &alloc, NULL) && alloc)
-      is_shm = GST_IS_WL_SHM_ALLOCATOR (alloc);
+      is_shm = GST_IS_SHM_ALLOCATOR (alloc);
 
     gst_structure_free (config);
 
@@ -645,7 +645,7 @@ gst_wayland_activate_shm_pool (GstWaylandSink * self)
       return TRUE;
   }
 
-  alloc = gst_wl_shm_allocator_get ();
+  alloc = gst_shm_allocator_get ();
   gst_wayland_update_pool (self, alloc);
   gst_object_unref (alloc);
 
@@ -779,7 +779,7 @@ gst_wayland_sink_propose_allocation (GstBaseSink * bsink, GstQuery * query)
     gst_buffer_pool_config_set_params (config,
         caps, self->video_info.size, 2, 0);
     gst_buffer_pool_config_set_allocator (config,
-        gst_wl_shm_allocator_get (), NULL);
+        gst_shm_allocator_get (), NULL);
     gst_buffer_pool_set_config (pool, config);
   }
 
@@ -787,7 +787,7 @@ gst_wayland_sink_propose_allocation (GstBaseSink * bsink, GstQuery * query)
   if (pool)
     g_object_unref (pool);
 
-  alloc = gst_wl_shm_allocator_get ();
+  alloc = gst_shm_allocator_get ();
   gst_query_add_allocation_param (query, alloc, NULL);
   gst_query_add_allocation_meta (query, GST_VIDEO_META_API_TYPE, NULL);
   g_object_unref (alloc);

subprojects/gst-plugins-bad/gst-libs/gst/wayland/gstwldisplay.c

@@ -93,7 +93,7 @@ gst_wl_display_init (GstWlDisplay * self)
   g_mutex_init (&priv->buffers_mutex);
 
   gst_wl_linux_dmabuf_init_once ();
-  gst_wl_shm_allocator_init_once ();
+  gst_shm_allocator_init_once ();
   gst_wl_videoformat_init_once ();
 }
 

subprojects/gst-plugins-bad/gst-libs/gst/wayland/gstwlshmallocator.c

@@ -26,137 +26,6 @@
 
 #include "gstwlshmallocator.h"
 
-#include <errno.h>
-#include <fcntl.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/mman.h>
-#include <sys/types.h>
-#include <unistd.h>
-#include <drm_fourcc.h>
-
-#define GST_CAT_DEFAULT gst_wl_shm_debug
-GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
-
-G_DEFINE_TYPE_WITH_CODE (GstWlShmAllocator, gst_wl_shm_allocator,
-    GST_TYPE_FD_ALLOCATOR,
-    GST_DEBUG_CATEGORY_INIT (gst_wl_shm_debug, "wlshm", 0, "wlshm library");
-    );
-
-static GstMemory *
-gst_wl_shm_allocator_alloc (GstAllocator * allocator, gsize size,
-    GstAllocationParams * params)
-{
-  GstWlShmAllocator *self = GST_WL_SHM_ALLOCATOR (allocator);
-  char filename[1024];
-  static int init = 0;
-  int fd;
-  GstMemory *mem;
-  GstMapInfo info;
-
-  /* TODO: make use of the allocation params, if necessary */
-
-#ifdef HAVE_MEMFD_CREATE
-  fd = memfd_create ("gst-wayland-shm", MFD_CLOEXEC | MFD_ALLOW_SEALING);
-  if (fd >= 0) {
-    /* We can add this seal before calling posix_fallocate(), as
-     * the file is currently zero-sized anyway.
-     *
-     * There is also no need to check for the return value, we
-     * couldn't do anything with it anyway.
-     */
-    fcntl (fd, F_ADD_SEALS, F_SEAL_SHRINK);
-  } else
-#endif
-  {
-    /* allocate shm pool */
-    snprintf (filename, 1024, "%s/%s-%d-%s", g_get_user_runtime_dir (),
-        "wayland-shm", init++, "XXXXXX");
-
-    fd = g_mkstemp (filename);
-    if (fd < 0) {
-      GST_ERROR_OBJECT (self, "opening temp file %s failed: %s", filename,
-          strerror (errno));
-      return NULL;
-    }
-
-    unlink (filename);
-  }
-
-  if (ftruncate (fd, size) < 0) {
-    GST_ERROR_OBJECT (self, "ftruncate failed: %s", strerror (errno));
-    close (fd);
-    return NULL;
-  }
-
-  mem = gst_fd_allocator_alloc (allocator, fd, size,
-      GST_FD_MEMORY_FLAG_KEEP_MAPPED);
-  if (G_UNLIKELY (!mem)) {
-    GST_ERROR_OBJECT (self, "GstFdMemory allocation failed");
-    close (fd);
-    return NULL;
-  }
-
-  /* we need to map the memory in order to unlink the file without losing it */
-  if (!gst_memory_map (mem, &info, GST_MAP_READWRITE)) {
-    GST_ERROR_OBJECT (self, "GstFdMemory map failed");
-    close (fd);
-    return NULL;
-  }
-
-  /* unmap will not really munmap(), we just
-   * need it to release the miniobject lock */
-  gst_memory_unmap (mem, &info);
-
-  return mem;
-}
-
-static void
-gst_wl_shm_allocator_class_init (GstWlShmAllocatorClass * klass)
-{
-  GstAllocatorClass *alloc_class = (GstAllocatorClass *) klass;
-
-  alloc_class->alloc = GST_DEBUG_FUNCPTR (gst_wl_shm_allocator_alloc);
-}
-
-static void
-gst_wl_shm_allocator_init (GstWlShmAllocator * self)
-{
-  GstAllocator *alloc = GST_ALLOCATOR_CAST (self);
-
-  alloc->mem_type = GST_ALLOCATOR_WL_SHM;
-
-  GST_OBJECT_FLAG_UNSET (self, GST_ALLOCATOR_FLAG_CUSTOM_ALLOC);
-}
-
-void
-gst_wl_shm_allocator_init_once (void)
-{
-  static gsize _init = 0;
-
-  if (g_once_init_enter (&_init)) {
-    GstAllocator *alloc;
-
-    alloc = g_object_new (GST_TYPE_WL_SHM_ALLOCATOR, NULL);
-    gst_object_ref_sink (alloc);
-    gst_allocator_register (GST_ALLOCATOR_WL_SHM, alloc);
-
-    g_once_init_leave (&_init, 1);
-  }
-}
-
-GstAllocator *
-gst_wl_shm_allocator_get (void)
-{
-  return gst_allocator_find (GST_ALLOCATOR_WL_SHM);
-}
-
-gboolean
-gst_is_wl_shm_memory (GstMemory * mem)
-{
-  return gst_memory_is_type (mem, GST_ALLOCATOR_WL_SHM);
-}
 
 static gboolean
 gst_wl_shm_validate_video_info (const GstVideoInfo * vinfo)

subprojects/gst-plugins-bad/gst-libs/gst/wayland/gstwlshmallocator.h

@@ -29,27 +29,6 @@
 
 G_BEGIN_DECLS
 
-#define GST_TYPE_WL_SHM_ALLOCATOR (gst_wl_shm_allocator_get_type ())
-
-GST_WL_API
-G_DECLARE_FINAL_TYPE (GstWlShmAllocator, gst_wl_shm_allocator, GST, WL_SHM_ALLOCATOR, GstFdAllocator);
-
-#define GST_ALLOCATOR_WL_SHM "wl_shm"
-
-struct _GstWlShmAllocator
-{
-  GstFdAllocator parent_instance;
-};
-
-GST_WL_API
-void gst_wl_shm_allocator_init_once (void);
-
-GST_WL_API
-GstAllocator * gst_wl_shm_allocator_get (void);
-
-GST_WL_API
-gboolean gst_is_wl_shm_memory (GstMemory * mem);
-
 GST_WL_API
 struct wl_buffer * gst_wl_shm_memory_construct_wl_buffer (GstMemory * mem,
     GstWlDisplay * display, const GstVideoInfo * info);

subprojects/gst-plugins-bad/gst-libs/gst/wayland/gstwlwindow.c

@@ -580,7 +580,7 @@ gst_wl_window_update_borders (GstWlWindow * self)
   /* draw the area_subsurface */
   gst_video_info_set_format (&info, format, width, height);
 
-  alloc = gst_wl_shm_allocator_get ();
+  alloc = gst_shm_allocator_get ();
 
   buf = gst_buffer_new_allocate (alloc, info.size, NULL);
   gst_buffer_memset (buf, 0, 0, info.size);

subprojects/gst-plugins-base/gst-libs/gst/allocators/allocators.h

@@ -28,6 +28,7 @@
 #include <gst/allocators/gstfdmemory.h>
 #include <gst/allocators/gstphysmemory.h>
 #include <gst/allocators/gstdrmdumb.h>
+#include <gst/allocators/gstshmallocator.h>
 
 #endif /* __GST_ALLOCATORS_H__ */
 

subprojects/gst-plugins-base/gst-libs/gst/allocators/gstshmallocator.c

@@ -0,0 +1,162 @@
+/* GStreamer shared memory allocator
+ *
+ * Copyright (C) 2012 Intel Corporation
+ * Copyright (C) 2012 Sreerenj Balachandran <sreerenj.balachandran@intel.com>
+ * Copyright (C) 2023 Netflix Inc.
+ *  Author: Xavier Claessens <xavier.claessens@collabora.com>
+ *
+ * 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "gstshmallocator.h"
+
+#ifdef HAVE_MMAP
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#endif
+
+struct _GstShmAllocator
+{
+  GstFdAllocator parent;
+};
+
+#define GST_CAT_DEFAULT gst_shm_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+G_DEFINE_TYPE_WITH_CODE (GstShmAllocator, gst_shm_allocator,
+    GST_TYPE_FD_ALLOCATOR,
+    GST_DEBUG_CATEGORY_INIT (gst_shm_debug, "shmallocator", 0,
+        "Shared memory allocator");
+    );
+
+static GstMemory *
+gst_shm_allocator_alloc (GstAllocator * allocator, gsize size,
+    GstAllocationParams * params)
+{
+#ifdef HAVE_MMAP
+  GstShmAllocator *self = GST_SHM_ALLOCATOR (allocator);
+  int fd;
+  GstMemory *mem;
+  GstMapInfo info;
+
+  /* TODO: make use of the allocation params, if necessary */
+
+#ifdef HAVE_MEMFD_CREATE
+  fd = memfd_create ("gst-shm", MFD_CLOEXEC | MFD_ALLOW_SEALING);
+  if (fd >= 0) {
+    /* We can add this seal before calling posix_fallocate(), as
+     * the file is currently zero-sized anyway.
+     *
+     * There is also no need to check for the return value, we
+     * couldn't do anything with it anyway.
+     */
+    fcntl (fd, F_ADD_SEALS, F_SEAL_SHRINK);
+  } else
+#endif
+  {
+    char filename[1024];
+    static int init = 0;
+
+    /* allocate shm pool */
+    snprintf (filename, 1024, "%s/%s-%d-%s", g_get_user_runtime_dir (),
+        "gst-shm", init++, "XXXXXX");
+
+    fd = g_mkstemp (filename);
+    if (fd < 0) {
+      GST_ERROR_OBJECT (self, "opening temp file %s failed: %s", filename,
+          strerror (errno));
+      return NULL;
+    }
+
+    unlink (filename);
+  }
+
+  if (ftruncate (fd, size) < 0) {
+    GST_ERROR_OBJECT (self, "ftruncate failed: %s", strerror (errno));
+    close (fd);
+    return NULL;
+  }
+
+  mem = gst_fd_allocator_alloc (allocator, fd, size,
+      GST_FD_MEMORY_FLAG_KEEP_MAPPED);
+  if (G_UNLIKELY (!mem)) {
+    GST_ERROR_OBJECT (self, "GstFdMemory allocation failed");
+    close (fd);
+    return NULL;
+  }
+
+  /* we need to map the memory in order to unlink the file without losing it */
+  if (!gst_memory_map (mem, &info, GST_MAP_READWRITE)) {
+    GST_ERROR_OBJECT (self, "GstFdMemory map failed");
+    close (fd);
+    return NULL;
+  }
+
+  /* unmap will not really munmap(), we just
+   * need it to release the miniobject lock */
+  gst_memory_unmap (mem, &info);
+
+  return mem;
+#else
+  return NULL;
+#endif
+}
+
+static void
+gst_shm_allocator_class_init (GstShmAllocatorClass * klass)
+{
+  GstAllocatorClass *alloc_class = (GstAllocatorClass *) klass;
+
+  alloc_class->alloc = GST_DEBUG_FUNCPTR (gst_shm_allocator_alloc);
+}
+
+static void
+gst_shm_allocator_init (GstShmAllocator * self)
+{
+  GstAllocator *alloc = GST_ALLOCATOR_CAST (self);
+
+  alloc->mem_type = GST_ALLOCATOR_SHM;
+
+  GST_OBJECT_FLAG_SET (self, GST_ALLOCATOR_FLAG_CUSTOM_ALLOC);
+}
+
+void
+gst_shm_allocator_init_once (void)
+{
+  static gsize _init = 0;
+
+  if (g_once_init_enter (&_init)) {
+    GstAllocator *alloc;
+
+    alloc = (GstAllocator *) g_object_new (GST_TYPE_SHM_ALLOCATOR, NULL);
+    gst_object_ref_sink (alloc);
+    gst_allocator_register (GST_ALLOCATOR_SHM, alloc);
+
+    g_once_init_leave (&_init, 1);
+  }
+}
+
+GstAllocator *
+gst_shm_allocator_get (void)
+{
+  return gst_allocator_find (GST_ALLOCATOR_SHM);
+}

subprojects/gst-plugins-base/gst-libs/gst/allocators/gstshmallocator.h

@@ -0,0 +1,39 @@
+/* GStreamer shared memory allocator
+ *
+ * Copyright (C) 2012 Intel Corporation
+ * Copyright (C) 2012 Sreerenj Balachandran <sreerenj.balachandran@intel.com>
+ * Copyright (C) 2023 Netflix Inc.
+ *  Author: Xavier Claessens <xavier.claessens@collabora.com>
+ *
+ * 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.
+ */
+
+#pragma once
+
+#include <gst/allocators/gstfdmemory.h>
+
+G_BEGIN_DECLS
+
+#define GST_ALLOCATOR_SHM "shm"
+
+#define GST_TYPE_SHM_ALLOCATOR gst_shm_allocator_get_type ()
+GST_ALLOCATORS_API
+G_DECLARE_FINAL_TYPE (GstShmAllocator, gst_shm_allocator, GST, SHM_ALLOCATOR, GstFdAllocator)
+
+GST_ALLOCATORS_API void gst_shm_allocator_init_once (void);
+GST_ALLOCATORS_API GstAllocator* gst_shm_allocator_get (void);
+
+G_END_DECLS

subprojects/gst-plugins-base/gst-libs/gst/allocators/meson.build

@@ -5,13 +5,34 @@ gst_allocators_headers = files([
   'gstphysmemory.h',
   'gstdmabuf.h',
   'gstdrmdumb.h',
+  'gstshmallocator.h',
 ])
 install_headers(gst_allocators_headers, subdir : 'gstreamer-1.0/gst/allocators/')
 
-gst_allocators_sources = files([ 'gstdrmdumb.c', 'gstdmabuf.c', 'gstfdmemory.c', 'gstphysmemory.c'])
+gst_allocators_sources = files([
+  'gstdrmdumb.c',
+  'gstdmabuf.c',
+  'gstfdmemory.c',
+  'gstphysmemory.c',
+  'gstshmallocator.c',
+])
+
+gst_allocators_cargs = [
+  gst_plugins_base_args,
+  '-DBUILDING_GST_ALLOCATORS',
+  '-DG_LOG_DOMAIN="GStreamer-Allocators"',
+]
+
+if cc.has_function('memfd_create')
+  gst_allocators_cargs += [
+    '-DHAVE_MEMFD_CREATE',
+    '-D_GNU_SOURCE',
+  ]
+endif
+
 gstallocators = library('gstallocators-@0@'.format(api_version),
   gst_allocators_sources,
-  c_args : gst_plugins_base_args + ['-DBUILDING_GST_ALLOCATORS', '-DG_LOG_DOMAIN="GStreamer-Allocators"'],
+  c_args : gst_allocators_cargs,
   include_directories: [configinc, libsinc],
   version : libversion,
   soversion : soversion,