OpenZFS 7431 - ZFS Channel Programs

Authored by: Chris Williamson <chris.williamson@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: John Kennedy <john.kennedy@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>
Ported-by: Don Brady <don.brady@delphix.com>
Ported-by: John Kennedy <john.kennedy@delphix.com>

OpenZFS-issue: https://www.illumos.org/issues/7431
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/dfc11533

Porting Notes:
* The CLI long option arguments for '-t' and '-m' don't parse on linux
* Switched from kmem_alloc to vmem_alloc in zcp_lua_alloc
* Lua implementation is built as its own module (zlua.ko)
* Lua headers consumed directly by zfs code moved to 'include/sys/lua/'
* There is no native setjmp/longjump available in stock Linux kernel.
  Brought over implementations from illumos and FreeBSD
* The get_temporary_prop() was adapted due to VFS platform differences
* Use of inline functions in lua parser to reduce stack usage per C call
* Skip some ZFS Test Suite ZCP tests on sparc64 to avoid stack overflow

module/lua/lzio.h

@@ -0,0 +1,67 @@
+/* BEGIN CSTYLED */
+/*
+** $Id: lzio.h,v 1.26.1.1 2013/04/12 18:48:47 roberto Exp $
+** Buffered streams
+** See Copyright Notice in lua.h
+*/
+
+
+#ifndef lzio_h
+#define lzio_h
+
+#include <sys/lua/lua.h>
+
+#include "lmem.h"
+
+
+#define EOZ	(-1)			/* end of stream */
+
+typedef struct Zio ZIO;
+
+#define zgetc(z)  (((z)->n--)>0 ?  cast_uchar(*(z)->p++) : luaZ_fill(z))
+
+
+typedef struct Mbuffer {
+  char *buffer;
+  size_t n;
+  size_t buffsize;
+} Mbuffer;
+
+#define luaZ_initbuffer(L, buff) ((buff)->buffer = NULL, (buff)->buffsize = 0)
+
+#define luaZ_buffer(buff)	((buff)->buffer)
+#define luaZ_sizebuffer(buff)	((buff)->buffsize)
+#define luaZ_bufflen(buff)	((buff)->n)
+
+#define luaZ_resetbuffer(buff) ((buff)->n = 0)
+
+
+#define luaZ_resizebuffer(L, buff, size) \
+	(luaM_reallocvector(L, (buff)->buffer, (buff)->buffsize, size, char), \
+	(buff)->buffsize = size)
+
+#define luaZ_freebuffer(L, buff)	luaZ_resizebuffer(L, buff, 0)
+
+
+LUAI_FUNC char *luaZ_openspace (lua_State *L, Mbuffer *buff, size_t n);
+LUAI_FUNC void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader,
+                                        void *data);
+LUAI_FUNC size_t luaZ_read (ZIO* z, void* b, size_t n);	/* read next n bytes */
+
+
+
+/* --------- Private Part ------------------ */
+
+struct Zio {
+  size_t n;			/* bytes still unread */
+  const char *p;		/* current position in buffer */
+  lua_Reader reader;		/* reader function */
+  void* data;			/* additional data */
+  lua_State *L;			/* Lua state (for reader) */
+};
+
+
+LUAI_FUNC int luaZ_fill (ZIO *z);
+
+#endif
+/* END CSTYLED */