lib9p: Add the DM bitfield

1 files changed, 30 insertions, 6 deletions

diff --git a/lib9p/types.c b/lib9p/types.c
index 50ac1cf..2d0bb1b 100644
--- a/lib9p/types.c
+++ b/lib9p/types.c
@@ -343,6 +343,22 @@ static ALWAYS_INLINE bool validate_s(struct _validate_ctx *ctx) {
 	return false;
 }
 
+static ALWAYS_INLINE bool validate_dm(struct _validate_ctx *ctx) {
+	 if (validate_4(ctx))
+		return true;
+	static const lib9p_dm_t masks[LIB9P_VER_NUM] = {
+		[LIB9P_VER_9P2000] = 0b11111100000000000000000111111111,
+		[LIB9P_VER_9P2000_e] = 0b11111100000000000000000111111111,
+		[LIB9P_VER_9P2000_u] = 0b11111100101111000000000111111111,
+	};
+	lib9p_dm_t mask = masks[ctx->ctx->version];
+	lib9p_dm_t val = decode_u32le(&ctx->net_bytes[ctx->net_offset-4]);
+	if (val & ~mask)
+		return lib9p_errorf(ctx->ctx, LINUX_EBADMSG, "unknown bits in dm bitfield: %#04"PRIx32,
+		                    val & ~mask);
+	return false;
+}
+
 static ALWAYS_INLINE bool validate_qt(struct _validate_ctx *ctx) {
 	 if (validate_1(ctx))
 		return true;
@@ -370,7 +386,7 @@ static ALWAYS_INLINE bool validate_stat(struct _validate_ctx *ctx) {
 	    || validate_2(ctx)
 	    || validate_4(ctx)
 	    || validate_qid(ctx)
-	    || validate_4(ctx)
+	    || validate_dm(ctx)
 	    || validate_4(ctx)
 	    || validate_4(ctx)
 	    || validate_8(ctx)
@@ -465,7 +481,7 @@ static FLATTEN bool validate_Ropen(struct _validate_ctx *ctx) {
 static FLATTEN bool validate_Tcreate(struct _validate_ctx *ctx) {
 	return validate_4(ctx)
 	    || validate_s(ctx)
-	    || validate_4(ctx)
+	    || validate_dm(ctx)
 	    || validate_o(ctx);
 }
 
@@ -596,6 +612,10 @@ static ALWAYS_INLINE void unmarshal_s(struct _unmarshal_ctx *ctx, struct lib9p_s
 		unmarshal_1(ctx, &out->utf8[i]);
 }
 
+static ALWAYS_INLINE void unmarshal_dm(struct _unmarshal_ctx *ctx, lib9p_dm_t *out) {
+	unmarshal_4(ctx, (uint32_t *)out);
+}
+
 static ALWAYS_INLINE void unmarshal_qt(struct _unmarshal_ctx *ctx, lib9p_qt_t *out) {
 	unmarshal_1(ctx, (uint8_t *)out);
 }
@@ -613,7 +633,7 @@ static ALWAYS_INLINE void unmarshal_stat(struct _unmarshal_ctx *ctx, struct lib9
 	unmarshal_2(ctx, &out->kern_type);
 	unmarshal_4(ctx, &out->kern_dev);
 	unmarshal_qid(ctx, &out->file_qid);
-	unmarshal_4(ctx, &out->file_mode);
+	unmarshal_dm(ctx, &out->file_mode);
 	unmarshal_4(ctx, &out->file_atime);
 	unmarshal_4(ctx, &out->file_mtime);
 	unmarshal_8(ctx, &out->file_size);
@@ -720,7 +740,7 @@ static FLATTEN void unmarshal_Tcreate(struct _unmarshal_ctx *ctx, struct lib9p_m
 	memset(out, 0, sizeof(*out));
 	unmarshal_4(ctx, &out->fid);
 	unmarshal_s(ctx, &out->name);
-	unmarshal_4(ctx, &out->perm);
+	unmarshal_dm(ctx, &out->perm);
 	unmarshal_o(ctx, &out->mode);
 }
 
@@ -894,6 +914,10 @@ static ALWAYS_INLINE bool marshal_s(struct _marshal_ctx *ctx, struct lib9p_s *va
 	       });
 }
 
+static ALWAYS_INLINE bool marshal_dm(struct _marshal_ctx *ctx, lib9p_dm_t *val) {
+	return marshal_4(ctx, (uint32_t *)val);
+}
+
 static ALWAYS_INLINE bool marshal_qt(struct _marshal_ctx *ctx, lib9p_qt_t *val) {
 	return marshal_1(ctx, (uint8_t *)val);
 }
@@ -909,7 +933,7 @@ static ALWAYS_INLINE bool marshal_stat(struct _marshal_ctx *ctx, struct lib9p_st
 	    || marshal_2(ctx, &val->kern_type)
 	    || marshal_4(ctx, &val->kern_dev)
 	    || marshal_qid(ctx, &val->file_qid)
-	    || marshal_4(ctx, &val->file_mode)
+	    || marshal_dm(ctx, &val->file_mode)
 	    || marshal_4(ctx, &val->file_atime)
 	    || marshal_4(ctx, &val->file_mtime)
 	    || marshal_8(ctx, &val->file_size)
@@ -1007,7 +1031,7 @@ static FLATTEN bool marshal_Ropen(struct _marshal_ctx *ctx, struct lib9p_msg_Rop
 static FLATTEN bool marshal_Tcreate(struct _marshal_ctx *ctx, struct lib9p_msg_Tcreate *val) {
 	return marshal_4(ctx, &val->fid)
 	    || marshal_s(ctx, &val->name)
-	    || marshal_4(ctx, &val->perm)
+	    || marshal_dm(ctx, &val->perm)
 	    || marshal_o(ctx, &val->mode);
 }