Merge branch 'lukeshu/9p-read-iovec'

1 files changed, 103 insertions, 42 deletions

diff --git a/lib9p/include/lib9p/srv.h b/lib9p/include/lib9p/srv.h
index 83aabc0..ff5ebdc 100644
--- a/lib9p/include/lib9p/srv.h
+++ b/lib9p/include/lib9p/srv.h
@@ -37,53 +37,98 @@ int lib9p_srv_acknowledge_flush(struct lib9p_srv_ctx *ctx);
 
 /* interface definitions ******************************************************/
 
-#define lib9p_srv_file_LO_IFACE                                                 \
-	/* all - resource management */                                         \
-	LO_FUNC(void                       , free   ) /* must not error */      \
-	LO_FUNC(struct lib9p_qid           , qid    ) /* must not error */      \
-	LO_FUNC(uint32_t                   , chio   , struct lib9p_srv_ctx *,   \
-	                                              bool rd, bool wr,         \
-	                                              bool trunc)               \
-	                                                                        \
-	/* all - syscalls */                                                    \
-	LO_FUNC(struct lib9p_stat          , stat   , struct lib9p_srv_ctx *)   \
-	LO_FUNC(void                       , wstat  , struct lib9p_srv_ctx *,   \
-	                                              struct lib9p_stat new)    \
-	LO_FUNC(void                       , remove , struct lib9p_srv_ctx *)   \
-	                                                                        \
-	/* directories - base */                                                \
-	LO_FUNC(lo_interface lib9p_srv_file, dopen  , struct lib9p_srv_ctx *,   \
-	                                              struct lib9p_s childname) \
-	LO_FUNC(lo_interface lib9p_srv_file, dcreate, struct lib9p_srv_ctx *,   \
-	                                              struct lib9p_s childname, \
-	                                              lib9p_dm_t perm,          \
-	                                              lib9p_o_t flags)          \
-	                                                                        \
-	/* directories - once opened */                                         \
-	LO_FUNC(size_t /* <- obj cnt */    , dread  , struct lib9p_srv_ctx *,   \
-	                                              uint8_t *buf,             \
-	                           /* num bytes -> */ uint32_t byte_count,      \
-	             /* starting at this object -> */ size_t obj_offset)        \
-	                                                                        \
-	/* non-directories - once opened */                                     \
-	LO_FUNC(uint32_t                   , pread  , struct lib9p_srv_ctx *,   \
-	                                              void *buf,                \
-	                                              uint32_t byte_count,      \
-	                                              uint64_t byte_offset)     \
-	LO_FUNC(uint32_t                   , pwrite , struct lib9p_srv_ctx *,   \
-	                                              void *buf,                \
-	                                              uint32_t byte_count,      \
+lo_interface lib9p_srv_fio;
+lo_interface lib9p_srv_dio;
+
+/* FIXME: I don't like that the pointers returned by stat() and
+ * pread() have to remain live after they return.  Perhaps a
+ * `respond()`-callback?  But that just reads as gross in C.
+ *
+ * FIXME: It would be nice if pread() could return more than 1 iovec.
+ */
+#define lib9p_srv_file_LO_IFACE                                                \
+	/* resource management **********************************************/ \
+	                                                                       \
+	/**                                                                    \
+	 * free() is be called when all FIDs associated with the file are      \
+	 * clunked.                                                            \
+	 *                                                                     \
+	 * free() MUST NOT error.                                              \
+	 */                                                                    \
+	LO_FUNC(void                       , free   )                          \
+	                                                                       \
+	/**                                                                    \
+	 * qid() is called frequently and returns the current QID of the file. \
+	 * The .path field MUST never change, the .type field may change in    \
+	 * response to wstat() calls (but the QT_DIR bit MUST NOT change), and \
+	 * the .vers field may change frequently in response to any number of  \
+	 * things (wstat(), write(), or non-9P events).                        \
+	 *                                                                     \
+	 * qid() MUST NOT error.                                               \
+	 */                                                                    \
+	LO_FUNC(struct lib9p_qid           , qid    )                          \
+	                                                                       \
+	/* non-"opened" generic I/O *****************************************/ \
+	                                                                       \
+	LO_FUNC(struct lib9p_stat          , stat   , struct lib9p_srv_ctx *)  \
+	LO_FUNC(void                       , wstat  , struct lib9p_srv_ctx *,  \
+	                                              struct lib9p_stat new)   \
+	LO_FUNC(void                       , remove , struct lib9p_srv_ctx *)  \
+	                                                                       \
+	/* non-"opened" directory I/O ***************************************/ \
+	                                                                       \
+	LO_FUNC(lo_interface lib9p_srv_file, dwalk  , struct lib9p_srv_ctx *,  \
+	                                             struct lib9p_s childname) \
+	LO_FUNC(lo_interface lib9p_srv_file, dcreate, struct lib9p_srv_ctx *,  \
+	                                             struct lib9p_s childname, \
+	                                              lib9p_dm_t perm,         \
+	                                              lib9p_o_t flags)         \
+	                                                                       \
+	/* open() for I/O ***************************************************/ \
+	                                                                       \
+	LO_FUNC(lo_interface lib9p_srv_fio , fopen , struct lib9p_srv_ctx *,   \
+	                                                    bool rd, bool wr,  \
+	                                                    bool trunc)        \
+	LO_FUNC(lo_interface lib9p_srv_dio , dopen , struct lib9p_srv_ctx *)
+LO_INTERFACE(lib9p_srv_file);
+
+#define lib9p_srv_fio_LO_IFACE                                                 \
+	LO_FUNC(struct lib9p_qid           , qid    )                          \
+	LO_FUNC(void                       , iofree )                          \
+	LO_FUNC(uint32_t                   , iounit )                          \
+	LO_FUNC(void                       , pread  , struct lib9p_srv_ctx *,  \
+	                                              uint32_t byte_count,     \
+	                                              uint64_t byte_offset,    \
+	                                              struct iovec *ret)       \
+	LO_FUNC(uint32_t                   , pwrite , struct lib9p_srv_ctx *,  \
+	                                              void *buf,               \
+	                                              uint32_t byte_count,     \
 	                                              uint64_t byte_offset)
-LO_INTERFACE(lib9p_srv_file)
+LO_INTERFACE(lib9p_srv_fio);
+
+/* FIXME: The dio interface just feels clunky.  I'm not in a rush to
+ * change it because util9p_static_dir is already implemented and I
+ * don't anticipate the sbc-harness needing another dio
+ * implementation.  But if I wanted lib9p to be used outside of
+ * sbc-harness, this is one of the first things that I'd want to
+ * change.
+ */
+#define lib9p_srv_dio_LO_IFACE                                                 \
+	LO_FUNC(struct lib9p_qid           , qid    )                          \
+	LO_FUNC(void                       , iofree )                          \
+	LO_FUNC(size_t /* <- obj cnt */    , dread  , struct lib9p_srv_ctx *,  \
+	                                              uint8_t *buf,            \
+	                           /* num bytes -> */ uint32_t byte_count,     \
+	             /* starting at this object -> */ size_t obj_offset)
+LO_INTERFACE(lib9p_srv_dio);
 
 #define LIB9P_SRV_NOTDIR(TYP, NAM)                                                                                                                                       \
-	static lo_interface lib9p_srv_file NAM##_dopen  (TYP *, struct lib9p_srv_ctx *, struct lib9p_s)                        { assert_notreached("not a directory"); } \
+	static lo_interface lib9p_srv_file NAM##_dwalk  (TYP *, struct lib9p_srv_ctx *, struct lib9p_s)                        { assert_notreached("not a directory"); } \
 	static lo_interface lib9p_srv_file NAM##_dcreate(TYP *, struct lib9p_srv_ctx *, struct lib9p_s, lib9p_dm_t, lib9p_o_t) { assert_notreached("not a directory"); } \
-	static size_t                      NAM##_dread  (TYP *, struct lib9p_srv_ctx *, uint8_t *, uint32_t, size_t)           { assert_notreached("not a directory"); }
+	static lo_interface lib9p_srv_dio  NAM##_dopen  (TYP *, struct lib9p_srv_ctx *)                                        { assert_notreached("not a directory"); }
 
 #define LIB9P_SRV_NOTFILE(TYP, NAM) \
-	static uint32_t NAM##_pread (TYP *, struct lib9p_srv_ctx *, void *, uint32_t, uint64_t) { assert_notreached("not a file"); } \
-	static uint32_t NAM##_pwrite(TYP *, struct lib9p_srv_ctx *, void *, uint32_t, uint64_t) { assert_notreached("not a file"); }
+	static lo_interface lib9p_srv_fio  NAM##_fopen  (TYP *, struct lib9p_srv_ctx *, bool, bool, bool)                      { assert_notreached("not a file"); }
 
 /* main server entrypoints ****************************************************/
 
@@ -103,16 +148,32 @@ struct lib9p_srv {
 };
 
 /**
+ * In an infinite loop, accept a connection and read messages from it until
+ * close; dispatching requests to a pool of lib9p_srv_write_cr() coroutines
+ * with the same `srv`.
+ *
  * Will just close the connection if a T-message has a size[4] <7.
  *
+ * @param srv: The server configuration and state; has an associated pool of
+ *             lib9p_srv_write_cr() coroutines.
+ * @param listener: The listener object to accept connections from.
+ *
  * @errno LINUX_EMSGSIZE T-message has size[4] bigger than max_msg_size
  * @errno LINUX_EDOM Tversion specified an impossibly small max_msg_size
  * @errno LINUX_EOPNOTSUPP T-message has an R-message type, or an unrecognized T-message type
  * @errno LINUX_EBADMSG T-message has wrong size[4] for its content, or has invalid UTF-8
  * @errno LINUX_ERANGE R-message does not fit into max_msg_size
  */
-
 [[noreturn]] void lib9p_srv_read_cr(struct lib9p_srv *srv, lo_interface net_stream_listener listener);
+
+/**
+ * Service requests to the `struct lib9p_srv *srv` argument that have been
+ * read by lib9p_srv_read_cr().
+ *
+ * @param struct lib9p_srv *srv: The server configuration and state; has an
+ *                               associated pool of lib9p_srv_read_cr()
+ *                               coroutines.
+ */
 COROUTINE lib9p_srv_write_cr(void *_srv);
 
 #endif /* _LIB9P_SRV_H_ */