#include <glib/gmessages.h>
#include <string.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#ifdef G_OS_UNIX
+#include "glib-unix.h"
+#include <sys/mman.h>
+#endif
/**
* GBytes:
{
gsize size;
gint ref_count;
- gint type;
+ gint type_or_fd;
};
typedef struct
#define G_BYTES_TYPE_NOTIFY (-4)
/* All bytes are either inline or subtypes of GBytesData */
-#define G_BYTES_IS_INLINE(bytes) ((bytes)->type == G_BYTES_TYPE_INLINE)
+#define G_BYTES_IS_INLINE(bytes) ((bytes)->type_or_fd == G_BYTES_TYPE_INLINE)
#define G_BYTES_IS_DATA(bytes) (!G_BYTES_IS_INLINE(bytes))
/* More specific subtypes of GBytesData */
-#define G_BYTES_IS_STATIC(bytes) ((bytes)->type == G_BYTES_TYPE_STATIC)
-#define G_BYTES_IS_FREE(bytes) ((bytes)->type == G_BYTES_TYPE_FREE)
-#define G_BYTES_IS_NOTIFY(bytes) ((bytes)->type == G_BYTES_TYPE_NOTIFY)
+#define G_BYTES_IS_STATIC(bytes) ((bytes)->type_or_fd == G_BYTES_TYPE_STATIC)
+#define G_BYTES_IS_FREE(bytes) ((bytes)->type_or_fd == G_BYTES_TYPE_FREE)
+#define G_BYTES_IS_NOTIFY(bytes) ((bytes)->type_or_fd == G_BYTES_TYPE_NOTIFY)
+
+/* we have a memfd if type_or_fd >= 0 */
+#define G_BYTES_IS_MEMFD(bytes) ((bytes)->type_or_fd >= 0)
static gpointer
g_bytes_allocate (guint struct_size,
- guint type,
+ guint type_or_fd,
gsize data_size)
{
GBytes *bytes;
bytes = g_slice_alloc (struct_size);
bytes->size = data_size;
bytes->ref_count = 1;
- bytes->type = type;
+ bytes->type_or_fd = type_or_fd;
return bytes;
}
}
/**
+ * g_bytes_new_take_zero_copy_fd:
+ * @fd: a file descriptor capable of being zero-copy-safe
+ *
+ * Creates a new #GBytes from @fd.
+ *
+ * @fd must be capable of being made zero-copy-safe. In concrete terms,
+ * this means that a call to g_unix_fd_ensure_zero_copy_safe() on @fd
+ * will succeed. This call will be made before returning.
+ *
+ * This call consumes @fd, transferring ownership to the returned
+ * #GBytes.
+ *
+ * Returns: (transfer full): a new #GBytes
+ *
+ * Since: 2.44
+ */
+#ifdef G_OS_UNIX
+GBytes *
+g_bytes_new_take_zero_copy_fd (gint fd)
+{
+ GBytesData *bytes;
+ struct stat buf;
+
+ g_return_val_if_fail_se (g_unix_fd_ensure_zero_copy_safe (fd), NULL);
+
+ /* We already checked this is a memfd... */
+ g_assert_se (fstat (fd, &buf) == 0);
+
+ bytes = g_bytes_allocate (sizeof (GBytesData), fd, buf.st_size);
+ bytes->data = mmap (NULL, buf.st_size, PROT_READ, MAP_SHARED, fd, 0);
+ if (bytes->data == MAP_FAILED)
+ /* this is similar to malloc() failing, so do the same... */
+ g_error ("mmap() on memfd failed: %s\n", g_strerror (errno));
+
+ return (GBytes *) bytes;
+}
+#endif /* G_OS_UNIX */
+
+/**
* g_bytes_new_take:
* @data: (transfer full) (array length=size) (element-type guint8) (allow-none):
the data to be used for the bytes
return bytes->size;
}
+/**
+ * g_bytes_get_zero_copy_fd:
+ * @bytes: a #GBytes
+ *
+ * Gets the zero-copy fd from a #GBytes, if it has one.
+ *
+ * Returns -1 if @bytes was not created from a zero-copy fd.
+ *
+ * A #GBytes created with a zero-copy fd may have been internally
+ * converted into another type of #GBytes for any reason at all. This
+ * function may therefore return -1 at any time, even for a #GBytes that
+ * was created with g_bytes_new_take_zero_copy_fd().
+ *
+ * The returned file descriptor belongs to @bytes. Do not close it.
+ *
+ * Returns: a file descriptor, or -1
+ *
+ * Since: 2.44
+ */
+gint
+g_bytes_get_zero_copy_fd (GBytes *bytes)
+{
+ g_return_val_if_fail (bytes != NULL, -1);
+
+ if (G_BYTES_IS_MEMFD (bytes))
+ return bytes->type_or_fd;
+ else
+ return -1;
+}
/**
* g_bytes_ref:
if (g_atomic_int_dec_and_test (&bytes->ref_count))
{
- switch (bytes->type)
+ switch (bytes->type_or_fd)
{
case G_BYTES_TYPE_STATIC:
/* data does not need to be freed */
}
default:
- g_assert_not_reached ();
+ {
+ GBytesData *data_bytes = (GBytesData *) bytes;
+
+ g_assert (bytes->type_or_fd >= 0);
+
+ g_assert_se (munmap (data_bytes->data, bytes->size) == 0);
+ g_assert_se (close (bytes->type_or_fd) == 0);
+
+ g_slice_free (GBytesData, data_bytes);
+ break;
+ }
}
}
}