implement dread

7 files changed, 174 insertions, 30 deletions

diff --git a/lib9p/9p.c b/lib9p/9p.c
index b1d4c32..832ae82 100644
--- a/lib9p/9p.c
+++ b/lib9p/9p.c
@@ -98,3 +98,50 @@ bool lib9p_marshal(struct lib9p_ctx *ctx, enum lib9p_msg_type typ, void *body,
 	struct _vtable_msg vtable = _lib9p_vtables[ctx->version].msgs[typ];
 	return vtable.marshal(&subctx, body);
 }
+
+bool lib9p_validate_stat(struct lib9p_ctx *ctx, uint32_t net_size, uint8_t *net_bytes,
+                         uint32_t *ret_net_size, ssize_t *ret_host_size) {
+	struct _validate_ctx subctx = {
+		.ctx        = ctx,
+		.net_size   = net_size,
+		.net_bytes  = net_bytes,
+
+		.net_offset = 0,
+		.host_extra = 0,
+	};
+	if (_lib9p_validate_stat(&subctx))
+		return true;
+	if (ret_net_size)
+		*ret_net_size = subctx.net_offset;
+	if (ret_host_size)
+		if (__builtin_add_overflow(sizeof(struct lib9p_stat), subctx.host_extra, ret_host_size))
+			return lib9p_error(ctx, LINUX_EMSGSIZE, "unmarshalled stat object overflows SSIZE_MAX");
+	return false;
+}
+
+uint32_t lib9p_unmarshal_stat(struct lib9p_ctx *ctx, uint8_t *net_bytes,
+                              struct lib9p_stat *ret_obj, void *ret_extra) {
+	struct _unmarshal_ctx subctx = {
+		.ctx = ctx,
+		.net_bytes = net_bytes,
+		.net_offset = 0,
+
+		.extra = ret_extra,
+	};
+	_lib9p_unmarshal_stat(&subctx, ret_obj);
+	return subctx.net_offset;
+}
+
+uint32_t lib9p_marshal_stat(struct lib9p_ctx *ctx, uint32_t max_net_size, struct lib9p_stat *obj,
+                            uint8_t *ret_bytes) {
+	struct lib9p_ctx _ctx = *ctx;
+	_ctx.max_msg_size = max_net_size;
+	struct _marshal_ctx subctx = {
+		.ctx        = &_ctx,
+		.net_bytes  = ret_bytes,
+		.net_offset = 0,
+	};
+	if (_lib9p_marshal_stat(&subctx, obj))
+		return 0;
+	return subctx.net_offset;
+}
diff --git a/lib9p/9p.generated.c b/lib9p/9p.generated.c
index 341acd0..660c925 100644
--- a/lib9p/9p.generated.c
+++ b/lib9p/9p.generated.c
@@ -1530,8 +1530,8 @@ static ALWAYS_INLINE bool marshal_qid(struct _marshal_ctx *ctx, struct lib9p_qid
 
 static ALWAYS_INLINE bool marshal_stat(struct _marshal_ctx *ctx, struct lib9p_stat *val) {
 	uint32_t _stat_size_offset;
-
-	uint32_t _kern_type_offset;	return false
+	uint32_t _kern_type_offset;
+	return false
 	    || ({ _stat_size_offset = ctx->net_offset; ({ ctx->net_offset += 2; false; }); })
 	    || ({ _kern_type_offset = ctx->net_offset; marshal_2(ctx, &val->kern_type); })
 	    || marshal_4(ctx, &val->kern_dev)
@@ -1908,8 +1908,8 @@ static FLATTEN bool marshal_Rstat(struct _marshal_ctx *ctx, struct lib9p_msg_Rst
 	uint32_t _size_offset;
 	uint32_t _typ_offset;
 	uint32_t _nstat_offset;
-
-	uint32_t _stat_offset;	return false
+	uint32_t _stat_offset;
+	return false
 	    || ({ _size_offset = ctx->net_offset; ({ ctx->net_offset += 4; false; }); })
 	    || ({ _typ_offset = ctx->net_offset; ({ ctx->net_offset += 1; false; }); })
 	    || marshal_tag(ctx, &val->tag)
@@ -1925,8 +1925,8 @@ static FLATTEN bool marshal_Twstat(struct _marshal_ctx *ctx, struct lib9p_msg_Tw
 	uint32_t _size_offset;
 	uint32_t _typ_offset;
 	uint32_t _nstat_offset;
-
-	uint32_t _stat_offset;	return false
+	uint32_t _stat_offset;
+	return false
 	    || ({ _size_offset = ctx->net_offset; ({ ctx->net_offset += 4; false; }); })
 	    || ({ _typ_offset = ctx->net_offset; ({ ctx->net_offset += 1; false; }); })
 	    || marshal_tag(ctx, &val->tag)
@@ -2041,7 +2041,7 @@ static FLATTEN bool marshal_Rswrite(struct _marshal_ctx *ctx, struct lib9p_msg_R
 	    ;
 }
 
-/* vtables ********************************************************************/
+/* vtables / exports **********************************************************/
 
 #define _MSG(typ) [LIB9P_TYP_##typ] = {                          \
 		.basesize  = sizeof(struct lib9p_msg_##typ),     \
@@ -2157,3 +2157,13 @@ struct _vtable_version _lib9p_vtables[LIB9P_VER_NUM] = {
 	}},
 #endif /* defined(CONFIG_9P_ENABLE_9P2000_u) */
 };
+
+FLATTEN bool _lib9p_validate_stat(struct _validate_ctx *ctx) {
+	return validate_stat(ctx);
+}
+FLATTEN void _lib9p_unmarshal_stat(struct _unmarshal_ctx *ctx, struct lib9p_stat *out) {
+	unmarshal_stat(ctx, out);
+}
+FLATTEN bool _lib9p_marshal_stat(struct _marshal_ctx *ctx, struct lib9p_stat *val) {
+    return marshal_stat(ctx, val);
+}
diff --git a/lib9p/idl.gen b/lib9p/idl.gen
index 8e7639a..c0a2444 100755
--- a/lib9p/idl.gen
+++ b/lib9p/idl.gen
@@ -1045,7 +1045,7 @@ static ALWAYS_INLINE bool marshal_8(struct _marshal_ctx *ctx, uint64_t *val) {
                     for tok in member.val.tokens:
                         if isinstance(tok, ExprSym) and tok.name.startswith("&"):
                             if tok.name[1:] not in mark_offset:
-                                ret += f"\n\tuint32_t _{tok.name[1:]}_offset;"
+                                ret += f"\tuint32_t _{tok.name[1:]}_offset;\n"
                             mark_offset.add(tok.name[1:])
 
                 # Pass 2 - main pass
@@ -1092,9 +1092,9 @@ static ALWAYS_INLINE bool marshal_8(struct _marshal_ctx *ctx, uint64_t *val) {
                 ret += "\t    ;\n"
         ret += "}\n"
 
-    # vtables ##################################################################
+    # vtables / exports ########################################################
     ret += f"""
-/* vtables ********************************************************************/
+/* vtables / exports **********************************************************/
 
 #define _MSG(typ) [{idprefix.upper()}TYP_##typ] = {{                          \\
 		.basesize  = sizeof(struct {idprefix}msg_##typ),     \\
@@ -1123,6 +1123,18 @@ struct _vtable_version _{idprefix}vtables[{c_ver_enum('NUM')}] = {{
     ret += ifdef_pop(0)
     ret += "};\n"
 
+    ret += f"""
+FLATTEN bool _{idprefix}validate_stat(struct _validate_ctx *ctx) {{
+	return validate_stat(ctx);
+}}
+FLATTEN void _{idprefix}unmarshal_stat(struct _unmarshal_ctx *ctx, struct lib9p_stat *out) {{
+	unmarshal_stat(ctx, out);
+}}
+FLATTEN bool _{idprefix}marshal_stat(struct _marshal_ctx *ctx, struct lib9p_stat *val) {{
+    return marshal_stat(ctx, val);
+}}
+"""
+
     ############################################################################
     return ret
 
diff --git a/lib9p/include/lib9p/9p.h b/lib9p/include/lib9p/9p.h
index c3c6a8b..1e1667d 100644
--- a/lib9p/include/lib9p/9p.h
+++ b/lib9p/include/lib9p/9p.h
@@ -113,7 +113,7 @@ void lib9p_unmarshal(struct lib9p_ctx *ctx, uint8_t *net_bytes,
  * @param typ : the message type
  * @param msg : the message to encode
  *
- * @return ret_bytes : the buffer to encode to, must be at be at least lib9p_ctx_max_msg_size(ctx) bytes
+ * @return ret_bytes : the buffer to encode to, must be at be at least ctx->max_msg_size bytes
  * @return whether there was an error (false=success, true=error)
  *
  * @errno LINUX_ERANGE: reply does not fit in ctx->max_msg_size
@@ -121,4 +121,31 @@ void lib9p_unmarshal(struct lib9p_ctx *ctx, uint8_t *net_bytes,
 bool lib9p_marshal(struct lib9p_ctx *ctx, enum lib9p_msg_type typ, void *body,
                    uint8_t *ret_bytes);
 
+/**
+ * TODO
+ *
+ * @return ret_net_size: number of bytes consumed; <=net_size
+ * @return ret_host_size: number of bytes that lib9p_unmarshal_stat would take
+ * @return whether there was an error
+ */
+bool lib9p_validate_stat(struct lib9p_ctx *ctx, uint32_t net_size, uint8_t *net_bytes,
+                            uint32_t *ret_net_size, ssize_t *ret_host_size);
+
+/**
+ * TODO
+ *
+ * @return ret_obj : where to put the stat object itself
+ * @return ret_extra : where to put strings for the stat object
+ * @return consumed net_bytes
+ */
+uint32_t lib9p_unmarshal_stat(struct lib9p_ctx *ctx, uint8_t *net_bytes,
+                              struct lib9p_stat *ret_obj, void *ret_extra);
+
+/**
+ * @return ret_bytes: the buffer to encode into
+ * @return the number of bytes written, or 0 if the stat object does not fit in max_net_size
+ */
+uint32_t lib9p_marshal_stat(struct lib9p_ctx *ctx, uint32_t max_net_size, struct lib9p_stat *obj,
+                            uint8_t *ret_bytes);
+
 #endif _LIB9P_9P_H_
diff --git a/lib9p/include/lib9p/srv.h b/lib9p/include/lib9p/srv.h
index 5df6b1a..7aca76c 100644
--- a/lib9p/include/lib9p/srv.h
+++ b/lib9p/include/lib9p/srv.h
@@ -57,17 +57,20 @@ struct lib9p_srv_file_vtable {
 	                                 lib9p_dm_t perm, lib9p_o_t flags);
 
 	/* directories - once opened */
-	size_t                 (*readdir)(struct lib9p_srv_ctx *, struct lib9p_srv_io_dir *,
-	                                  struct lib9p_stat *buf, size_t count,
-	                                  size_t offset);
+	size_t /* <- obj cnt */(*dread  )(struct lib9p_srv_ctx *, struct lib9p_srv_file *,
+	                                  uint8_t *buf,
+	                                  uint32_t byte_count, /* <- num bytes */
+	                                  size_t obj_offset); /* <- starting at this object */
 
 	/* non-directories - once opened */
-	uint32_t               (*pread  )(struct lib9p_srv_ctx *, struct lib9p_srv_io_file *,
-	                                  void *buf, uint32_t count,
-	                                  uint64_t offset);
-	uint32_t               (*pwrite )(struct lib9p_srv_ctx *, struct lib9p_srv_io_file *,
-	                                  void *buf, uint32_t count,
-	                                  uint64_t offset);
+	uint32_t               (*pread  )(struct lib9p_srv_ctx *, struct lib9p_srv_file *,
+	                                  void *buf,
+	                                  uint32_t byte_count,
+	                                  uint64_t byte_offset);
+	uint32_t               (*pwrite )(struct lib9p_srv_ctx *, struct lib9p_srv_file *,
+	                                  void *buf,
+	                                  uint32_t byte_count,
+	                                  uint64_t byte_offset);
 };
 
 /* objects you'll deal with ***************************************************/
@@ -83,8 +86,9 @@ struct lib9p_srv_file {
 	 * ref type 2: ->_parent_dir of another file */
 	struct lib9p_srv_file           *_refcount;
 	lib9p_o_t                        _io_flags;
-	struct lib9p_qid                 _io_qid;
-	uint32_t                         _io_unit;
+	bool                             _io_isdir;
+	size_t                           _io_dir_idx;
+	uint32_t                         _io_dir_off;
 
 	/* This is where your implementation data goes.  */
 	char                             data[0];
diff --git a/lib9p/internal.h b/lib9p/internal.h
index 2b5f8f3..013024e 100644
--- a/lib9p/internal.h
+++ b/lib9p/internal.h
@@ -90,6 +90,10 @@ struct _vtable_version {
 
 extern struct _vtable_version _lib9p_vtables[LIB9P_VER_NUM];
 
+bool _lib9p_validate_stat(struct _validate_ctx *ctx);
+void _lib9p_unmarshal_stat(struct _unmarshal_ctx *ctx, struct lib9p_stat *out);
+bool _lib9p_marshal_stat(struct _marshal_ctx *ctx, struct lib9p_stat *val);
+
 /* unmarshal utilities ********************************************************/
 
 static ALWAYS_INLINE uint8_t decode_u8le(uint8_t *in) {
diff --git a/lib9p/srv.c b/lib9p/srv.c
index 8940afe..04cd119 100644
--- a/lib9p/srv.c
+++ b/lib9p/srv.c
@@ -729,12 +729,10 @@ static void handle_Topen(struct _lib9p_srv_req *ctx,
 	if (lib9p_ctx_has_error(&ctx->ctx.basectx))
 		return;
 
-	filep->_io_flags = flags;
-	filep->_io_unit = iounit;
-	filep->_io_qid = stat.file_qid;
-
-	resp->qid = filep->_io_qid;
-	resp->iounit = filep->_io_unit;
+	filep->_io_flags = filep->_io_flags | flags;
+	filep->_io_isdir = stat.file_mode & LIB9P_DM_DIR;
+	resp->qid = stat.file_qid;
+	resp->iounit = iounit;
 }
 
 static void handle_Tcreate(struct _lib9p_srv_req *ctx,
@@ -751,8 +749,50 @@ static void handle_Tread(struct _lib9p_srv_req *ctx,
                          struct lib9p_msg_Rread *resp) {
 	handler_common(ctx, req, resp);
 
-	lib9p_error(&ctx->ctx.basectx,
-	            LINUX_EOPNOTSUPP, "read not yet implemented");
+	struct lib9p_srv_file **filepp = fidmap_load(&ctx->parent_sess->fids, req->fid);
+	if (!filepp) {
+		lib9p_errorf(&ctx->ctx.basectx,
+		             LINUX_EBADF, "bad file number %"PRIu32, req->fid);
+		return;
+	}
+	struct lib9p_srv_file *filep = *filepp;
+
+	switch (filep->_io_flags & LIB9P_O_MODE_MASK) {
+	case LIB9P_O_READ:
+	case LIB9P_O_RDWR:
+		/* ok */
+		break;
+	default:
+		lib9p_error(&ctx->ctx.basectx,
+		            LINUX_EINVAL, "FID not open for reading");
+		return;
+	}
+
+	resp->data.dat = (char *)(&resp[1]);
+	if (filep->_io_isdir) {
+		size_t idx;
+		if (req->offset == 0)
+			idx = 0;
+		else if (req->offset == filep->_io_dir_off)
+			idx = filep->_io_dir_idx;
+		else {
+			lib9p_errorf(&ctx->ctx.basectx,
+			             LINUX_EINVAL, "invalid offset (must be 0 or %"PRIu32"): %"PRIu32,
+			             filep->_io_dir_off, req->offset);
+			return;
+		}
+		size_t num = filep->vtable->dread(&ctx->ctx, filep, (uint8_t *)resp->data.dat, req->count, idx);
+		filep->_io_dir_idx = idx+num;
+		uint32_t len = 0;
+		for (size_t i = 0; i < num; i++) {
+			uint32_t i_len;
+			lib9p_validate_stat(&ctx->ctx.basectx, req->count, (uint8_t *)resp->data.dat, &i_len, NULL);
+			len += i_len;
+		}
+		filep->_io_dir_off = req->offset + len;
+		resp->data.len = len;
+	} else
+		resp->data.len = filep->vtable->pread(&ctx->ctx, filep, resp->data.dat, req->count, req->offset);
 }
 
 static void handle_Twrite(struct _lib9p_srv_req *ctx,