Merge branch 'lukeshu/9p-tests'HEADmain

24 files changed, 782 insertions, 140 deletions

diff --git a/.editorconfig b/.editorconfig
index 23d17cc..7aadb15 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -64,10 +64,13 @@ _mode = man-cat
 [lib9p/idl/*.9p{,.wip}]
 _mode = 9p-idl
 
+[lib9p/tests/*.explog]
+_mode = 9p-log
+
 [{lib9p/tests/test_server/static.h.gen,lib9p/tests/test_compile.c.gen}]
 _mode = sh
 
-[{lib9p/linux-errno.txt.gen,lib9p/tests/runtest}]
+[{lib9p/linux-errno.txt.gen,lib9p/tests/runtest,lib9p/tests/testclient-p9p}]
 _mode = bash
 
 [{lib9p/proto.gen,lib9p/include/lib9p/linux-errno.h.gen}]
diff --git a/GNUmakefile b/GNUmakefile
index 4183e37..904977d 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -132,7 +132,7 @@ lint/python3: lint/%: build-aux/venv
 	./build-aux/venv/bin/pylint $(sources_$*)
 	! grep -nh 'SPECIAL$$' -- lib9p/proto.gen lib9p/protogen/*.py
 	./build-aux/venv/bin/pytest $(foreach f,$(sources_python3),$(if $(filter test_%.py,$(notdir $f)),$f))
-lint/make lint/cmake lint/gitignore lint/ini lint/9p-idl lint/markdown lint/pip lint/man-cat: lint/%:
+lint/make lint/cmake lint/gitignore lint/ini lint/9p-idl lint/9p-log lint/markdown lint/pip lint/man-cat: lint/%:
 	@: TODO: Write/adopt linters for these file types
 
 # `format` #############################
@@ -148,5 +148,5 @@ format/sh format/bash: format/%:
 format/python3: format/%: ./build-aux/venv
 	./build-aux/venv/bin/black $(sources_$*)
 	./build-aux/venv/bin/isort $(sources_$*)
-format/make format/cmake format/gitignore format/ini format/9p-idl format/markdown format/pip format/man-cat: format/%:
+format/make format/cmake format/gitignore format/ini format/9p-idl format/9p-log format/markdown format/pip format/man-cat: format/%:
 	@: TODO: Write/adopt formatters for these file types
diff --git a/build-aux/valgrind b/build-aux/valgrind
index 728faca..7ad2712 100755
--- a/build-aux/valgrind
+++ b/build-aux/valgrind
@@ -6,6 +6,7 @@
 
 exec \
 	valgrind \
+	--fair-sched=yes \
 	--error-exitcode=2 \
 	--leak-check=full \
 	--show-leak-kinds=all \
diff --git a/lib9p/9p.generated.c b/lib9p/9p.generated.c
index b58a485..284a0a6 100644
--- a/lib9p/9p.generated.c
+++ b/lib9p/9p.generated.c
@@ -2019,11 +2019,11 @@ static void unmarshal_Rerror([[gnu::unused]] struct lib9p_ctx *ctx, uint8_t *net
 	net_offset += 4;
 	net_offset += 1;
 	UNMARSHAL_U16LE(ctx, out->tag);
-	UNMARSHAL_U16LE(ctx, out->ename.len);
-	UNMARSHAL_BYTES(ctx, out->ename.utf8, out->ename.len);
+	UNMARSHAL_U16LE(ctx, out->errstr.len);
+	UNMARSHAL_BYTES(ctx, out->errstr.utf8, out->errstr.len);
 #if CONFIG_9P_ENABLE_9P2000_u
 	if (is_ver(ctx, 9P2000_u)) {
-		UNMARSHAL_U32LE(ctx, out->errno);
+		UNMARSHAL_U32LE(ctx, out->errnum);
 	}
 #endif /* CONFIG_9P_ENABLE_9P2000_u */
 }
@@ -2353,7 +2353,7 @@ static void unmarshal_Rlerror([[gnu::unused]] struct lib9p_ctx *ctx, uint8_t *ne
 	net_offset += 4;
 	net_offset += 1;
 	UNMARSHAL_U16LE(ctx, out->tag);
-	UNMARSHAL_U32LE(ctx, out->ecode);
+	UNMARSHAL_U32LE(ctx, out->errnum);
 }
 
 static void unmarshal_Tstatfs([[gnu::unused]] struct lib9p_ctx *ctx, uint8_t *net_bytes, void *out_buf) {
@@ -3154,7 +3154,7 @@ static bool marshal_Rattach(struct lib9p_ctx *ctx, struct lib9p_msg_Rattach *val
 }
 
 static bool marshal_Rerror(struct lib9p_ctx *ctx, struct lib9p_msg_Rerror *val, struct _marshal_ret *ret) {
-	uint32_t needed_size = 9 + val->ename.len;
+	uint32_t needed_size = 9 + val->errstr.len;
 #if CONFIG_9P_ENABLE_9P2000_u
 	if is_ver(ctx, 9P2000_u) {
 		needed_size += 4;
@@ -3172,11 +3172,11 @@ static bool marshal_Rerror(struct lib9p_ctx *ctx, struct lib9p_msg_Rerror *val,
 	MARSHAL_U32LE(ctx, offsetof_end - offsetof_size);
 	MARSHAL_U8LE(ctx, 107);
 	MARSHAL_U16LE(ctx, val->tag);
-	MARSHAL_U16LE(ctx, val->ename.len);
-	MARSHAL_BYTES_ZEROCOPY(ctx, val->ename.utf8, val->ename.len);
+	MARSHAL_U16LE(ctx, val->errstr.len);
+	MARSHAL_BYTES_ZEROCOPY(ctx, val->errstr.utf8, val->errstr.len);
 #if CONFIG_9P_ENABLE_9P2000_u
 	if (is_ver(ctx, 9P2000_u)) {
-		MARSHAL_U32LE(ctx, val->errno);
+		MARSHAL_U32LE(ctx, val->errnum);
 	}
 #endif /* CONFIG_9P_ENABLE_9P2000_u */
 	return false;
@@ -3715,7 +3715,7 @@ static bool marshal_Rlerror(struct lib9p_ctx *ctx, struct lib9p_msg_Rlerror *val
 	MARSHAL_U32LE(ctx, offsetof_end - offsetof_size);
 	MARSHAL_U8LE(ctx, 7);
 	MARSHAL_U16LE(ctx, val->tag);
-	MARSHAL_U32LE(ctx, val->ecode);
+	MARSHAL_U32LE(ctx, val->errnum);
 	return false;
 }
 
@@ -4665,7 +4665,6 @@ static void lib9p_fid_format(lib9p_fid_t *self, struct fmt_state *state) {
 }
 
 static void lib9p_s_format(struct lib9p_s *self, struct fmt_state *state) {
-	/* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47781 */
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wformat"
 #pragma GCC diagnostic ignored "-Wformat-extra-args"
@@ -5141,11 +5140,11 @@ static void lib9p_msg_Rerror_format(struct lib9p_msg_Rerror *self, struct fmt_st
 	fmt_state_puts(state, "Rerror {");
 	fmt_state_puts(state, " tag=");
 	lib9p_tag_format(&self->tag, state);
-	fmt_state_puts(state, " ename=");
-	lib9p_s_format(&self->ename, state);
+	fmt_state_puts(state, " errstr=");
+	lib9p_s_format(&self->errstr, state);
 #if CONFIG_9P_ENABLE_9P2000_u
-	fmt_state_puts(state, " errno=");
-	lib9p_errno_format(&self->errno, state);
+	fmt_state_puts(state, " errnum=");
+	lib9p_errno_format(&self->errnum, state);
 #endif /* CONFIG_9P_ENABLE_9P2000_u */
 	fmt_state_puts(state, " }");
 }
@@ -5273,7 +5272,18 @@ static void lib9p_msg_Rread_format(struct lib9p_msg_Rread *self, struct fmt_stat
 	lib9p_tag_format(&self->tag, state);
 	fmt_state_puts(state, " count=");
 	fmt_state_printf(state, "%"PRIu32, self->count);
-	fmt_state_puts(state, " data=<bytedata>");
+	if (is_valid_utf8_without_nul((uint8_t *)self->data, (size_t)self->count)) {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wformat"
+#pragma GCC diagnostic ignored "-Wformat-extra-args"
+		fmt_state_printf(state, " data=%.*q%s",
+			(int)(self->count < 50 ? self->count : 50),
+			(char *)self->data,
+			self->count < 50 ? "" : "...");
+#pragma GCC diagnostic pop
+	} else {
+		fmt_state_puts(state, " data=<bytedata>");
+	}
 	fmt_state_puts(state, " }");
 }
 
@@ -5287,7 +5297,18 @@ static void lib9p_msg_Twrite_format(struct lib9p_msg_Twrite *self, struct fmt_st
 	fmt_state_printf(state, "%"PRIu64, self->offset);
 	fmt_state_puts(state, " count=");
 	fmt_state_printf(state, "%"PRIu32, self->count);
-	fmt_state_puts(state, " data=<bytedata>");
+	if (is_valid_utf8_without_nul((uint8_t *)self->data, (size_t)self->count)) {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wformat"
+#pragma GCC diagnostic ignored "-Wformat-extra-args"
+		fmt_state_printf(state, " data=%.*q%s",
+			(int)(self->count < 50 ? self->count : 50),
+			(char *)self->data,
+			self->count < 50 ? "" : "...");
+#pragma GCC diagnostic pop
+	} else {
+		fmt_state_puts(state, " data=<bytedata>");
+	}
 	fmt_state_puts(state, " }");
 }
 
@@ -6752,8 +6773,8 @@ static void lib9p_msg_Rlerror_format(struct lib9p_msg_Rlerror *self, struct fmt_
 	fmt_state_puts(state, "Rlerror {");
 	fmt_state_puts(state, " tag=");
 	lib9p_tag_format(&self->tag, state);
-	fmt_state_puts(state, " ecode=");
-	lib9p_errno_format(&self->ecode, state);
+	fmt_state_puts(state, " errnum=");
+	lib9p_errno_format(&self->errnum, state);
 	fmt_state_puts(state, " }");
 }
 
@@ -7086,7 +7107,18 @@ static void lib9p_msg_Rreaddir_format(struct lib9p_msg_Rreaddir *self, struct fm
 	lib9p_tag_format(&self->tag, state);
 	fmt_state_puts(state, " count=");
 	fmt_state_printf(state, "%"PRIu32, self->count);
-	fmt_state_puts(state, " data=<bytedata>");
+	if (is_valid_utf8_without_nul((uint8_t *)self->data, (size_t)self->count)) {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wformat"
+#pragma GCC diagnostic ignored "-Wformat-extra-args"
+		fmt_state_printf(state, " data=%.*q%s",
+			(int)(self->count < 50 ? self->count : 50),
+			(char *)self->data,
+			self->count < 50 ? "" : "...");
+#pragma GCC diagnostic pop
+	} else {
+		fmt_state_puts(state, " data=<bytedata>");
+	}
 	fmt_state_puts(state, " }");
 }
 
@@ -7302,7 +7334,18 @@ static void lib9p_msg_Rsread_format(struct lib9p_msg_Rsread *self, struct fmt_st
 	lib9p_tag_format(&self->tag, state);
 	fmt_state_puts(state, " count=");
 	fmt_state_printf(state, "%"PRIu32, self->count);
-	fmt_state_puts(state, " data=<bytedata>");
+	if (is_valid_utf8_without_nul((uint8_t *)self->data, (size_t)self->count)) {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wformat"
+#pragma GCC diagnostic ignored "-Wformat-extra-args"
+		fmt_state_printf(state, " data=%.*q%s",
+			(int)(self->count < 50 ? self->count : 50),
+			(char *)self->data,
+			self->count < 50 ? "" : "...");
+#pragma GCC diagnostic pop
+	} else {
+		fmt_state_puts(state, " data=<bytedata>");
+	}
 	fmt_state_puts(state, " }");
 }
 
@@ -7323,7 +7366,18 @@ static void lib9p_msg_Tswrite_format(struct lib9p_msg_Tswrite *self, struct fmt_
 	fmt_state_puts(state, " ]");
 	fmt_state_puts(state, " count=");
 	fmt_state_printf(state, "%"PRIu32, self->count);
-	fmt_state_puts(state, " data=<bytedata>");
+	if (is_valid_utf8_without_nul((uint8_t *)self->data, (size_t)self->count)) {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wformat"
+#pragma GCC diagnostic ignored "-Wformat-extra-args"
+		fmt_state_printf(state, " data=%.*q%s",
+			(int)(self->count < 50 ? self->count : 50),
+			(char *)self->data,
+			self->count < 50 ? "" : "...");
+#pragma GCC diagnostic pop
+	} else {
+		fmt_state_puts(state, " data=<bytedata>");
+	}
 	fmt_state_puts(state, " }");
 }
 
diff --git a/lib9p/CMakeLists.txt b/lib9p/CMakeLists.txt
index d433a12..949b6d6 100644
--- a/lib9p/CMakeLists.txt
+++ b/lib9p/CMakeLists.txt
@@ -20,10 +20,28 @@ target_link_libraries(lib9p INTERFACE
 
 if (ENABLE_TESTS)
 	add_subdirectory(tests/test_server)
-	add_test(
-		NAME    "lib9p/runtest"
-		COMMAND "${CMAKE_CURRENT_SOURCE_DIR}/tests/runtest"
-	)
+
+	function(add_lib9p_executable arg_testname)
+		add_executable("${arg_testname}" "tests/${arg_testname}.c")
+		target_link_libraries("${arg_testname}" lib9p)
+		target_include_directories("${arg_testname}" PRIVATE
+			${CMAKE_CURRENT_SOURCE_DIR}/tests
+			${CMAKE_CURRENT_SOURCE_DIR}/tests/client_config
+		)
+	endfunction()
+	function(add_lib9p_test arg_testscript)
+		get_filename_component(tmp_basename "${arg_testscript}" "NAME")
+		add_test(
+			NAME    "lib9p/${tmp_basename}"
+			COMMAND "${CMAKE_CURRENT_SOURCE_DIR}/tests/runtest" "${arg_testscript}" "${CMAKE_CURRENT_SOURCE_DIR}/tests/${tmp_basename}.explog"
+		)
+	endfunction()
+
+	add_lib9p_test("${CMAKE_CURRENT_SOURCE_DIR}/tests/testclient-p9p")
+
+	add_lib9p_executable("testclient-sess")
+	add_lib9p_test("./testclient-sess")
+
 	add_lib_test(lib9p test_compile)
 	target_include_directories(test_compile PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/tests/test_compile_config)
 endif()
diff --git a/lib9p/idl/1992-9P0.9p.wip b/lib9p/idl/1992-9P0.9p.wip
index a434ba2..c9432c9 100644
--- a/lib9p/idl/1992-9P0.9p.wip
+++ b/lib9p/idl/1992-9P0.9p.wip
@@ -107,7 +107,7 @@ msg Rnop      = "typ[1,val=51] tag[tag,val=0xFFFF]"
 msg Tsession  = "typ[1,val=52] tag[tag,val=0xFFFF]"
 msg Rsession  = "typ[1,val=53] tag[tag,val=0xFFFF]"
 #msg Terror    = "typ[1,val=54] illegal"
-msg Rerror    = "typ[1,val=55] tag[tag] ename[errstr]"
+msg Rerror    = "typ[1,val=55] tag[tag] errstr[errstr]"
 msg Tflush    = "typ[1,val=56] tag[tag] oldtag[tag]"
 msg Rflush    = "typ[1,val=57] tag[tag]"
 msg Tattach   = "typ[1,val=58] tag[tag] fid[fid] uid[name] aname[name] auth[auth_ticket] 13*(pad[1])" # Pad to allow auth_tickets up to 28 bytes.
diff --git a/lib9p/idl/1996-Styx.9p.wip b/lib9p/idl/1996-Styx.9p.wip
index 3cb3774..143be83 100644
--- a/lib9p/idl/1996-Styx.9p.wip
+++ b/lib9p/idl/1996-Styx.9p.wip
@@ -28,7 +28,7 @@ from ./1992-9P1.9p import tag, fid, qid, name, errstr, o, ch, stat
 msg Tnop     = "typ[1,val=0] tag[tag,val=0xFFFF]"
 msg Rnop     = "typ[1,val=1] tag[tag,val=0xFFFF]"
 #msg Terror   = "typ[1,val=2] illegal"
-msg Rerror   = "typ[1,val=3] tag[tag] ename[errstr]"
+msg Rerror   = "typ[1,val=3] tag[tag] errstr[errstr]"
 msg Tflush   = "typ[1,val=4] tag[tag] oldtag[tag]"
 msg Rflush   = "typ[1,val=5] tag[tag]"
 msg Tclone   = "typ[1,val=6] tag[tag] fid[fid] newfid[fid]"
diff --git a/lib9p/idl/2002-9P2000.9p b/lib9p/idl/2002-9P2000.9p
index 2b51612..13393c6 100644
--- a/lib9p/idl/2002-9P2000.9p
+++ b/lib9p/idl/2002-9P2000.9p
@@ -137,7 +137,7 @@ msg Rauth    = "size[4,val=end-&size] typ[1,val=103] tag[tag] aqid[qid]"
 msg Tattach  = "size[4,val=end-&size] typ[1,val=104] tag[tag] fid[fid] afid[fid] uname[s] aname[s]"
 msg Rattach  = "size[4,val=end-&size] typ[1,val=105] tag[tag] qid[qid]"
 #msg Terror   = "size[4,val=end-&size] typ[1,val=106] tag[tag] illegal"
-msg Rerror   = "size[4,val=end-&size] typ[1,val=107] tag[tag] ename[s]"
+msg Rerror   = "size[4,val=end-&size] typ[1,val=107] tag[tag] errstr[s]"
 msg Tflush   = "size[4,val=end-&size] typ[1,val=108] tag[tag] oldtag[2]"
 msg Rflush   = "size[4,val=end-&size] typ[1,val=109] tag[tag]"
 msg Twalk    = "size[4,val=end-&size] typ[1,val=110] tag[tag] fid[fid] newfid[fid] nwname[2,max=16] nwname*(wname[s])"
diff --git a/lib9p/idl/2005-9P2000.u.9p b/lib9p/idl/2005-9P2000.u.9p
index 6c2f2dc..1d630f9 100644
--- a/lib9p/idl/2005-9P2000.u.9p
+++ b/lib9p/idl/2005-9P2000.u.9p
@@ -25,7 +25,7 @@ struct stat += "file_extension[s]"
 msg Tauth   += "n_uid[nuid]"
 msg Tattach += "n_uid[nuid]"
 
-msg Rerror += "errno[errno]"
+msg Rerror += "errnum[errno]"
 
 bitfield dm += "bit 23=DEVICE"
                "bit 21=PIPE"
diff --git a/lib9p/idl/2010-9P2000.L.9p b/lib9p/idl/2010-9P2000.L.9p
index d81a15b..652660c 100644
--- a/lib9p/idl/2010-9P2000.L.9p
+++ b/lib9p/idl/2010-9P2000.L.9p
@@ -169,7 +169,7 @@ num lock_status = 1
 	"GRACE=3"
 
 #msg Tlerror      = "size[4,val=end-&size] typ[1,val=6]  tag[tag] illegal" # analogous to 106/Terror
-msg Rlerror      = "size[4,val=end-&size] typ[1,val=7]  tag[tag] ecode[errno]" # analogous to 107/Rerror
+msg Rlerror      = "size[4,val=end-&size] typ[1,val=7]  tag[tag] errnum[errno]" # analogous to 107/Rerror
 msg Tstatfs      = "size[4,val=end-&size] typ[1,val=8]  tag[tag] fid[fid]"
 msg Rstatfs      = "size[4,val=end-&size] typ[1,val=9]  tag[tag]"          # Description                                  | statfs                       | statvfs
                                                        "type[super_magic]" # Type of filesystem                           | f_type                       | -
diff --git a/lib9p/include/lib9p/9p.generated.h b/lib9p/include/lib9p/9p.generated.h
index afd89ed..a53f117 100644
--- a/lib9p/include/lib9p/9p.generated.h
+++ b/lib9p/include/lib9p/9p.generated.h
@@ -975,9 +975,9 @@ LO_IMPLEMENTATION_H(fmt_formatter, struct lib9p_msg_Topenfd, lib9p_msg_Topenfd);
 /* LIB9P_VER_9P2000_u  : min_size = 13 ; exp_size = 40 ; max_size = 65,548 ; max_iov = 3 ; max_copy = 13 */
 struct lib9p_msg_Rerror {
 	lib9p_tag_t      tag;
-	struct lib9p_s   ename;
+	struct lib9p_s   errstr;
 #if CONFIG_9P_ENABLE_9P2000_u
-	lib9p_errno_t    errno;
+	lib9p_errno_t    errnum;
 #endif /* CONFIG_9P_ENABLE_9P2000_u */
 };
 LO_IMPLEMENTATION_H(fmt_formatter, struct lib9p_msg_Rerror, lib9p_msg_Rerror);
@@ -987,7 +987,7 @@ LO_IMPLEMENTATION_H(fmt_formatter, struct lib9p_msg_Rerror, lib9p_msg_Rerror);
 /* size = 11 ; max_iov = 1 ; max_copy = 11 */
 struct lib9p_msg_Rlerror {
 	lib9p_tag_t     tag;
-	lib9p_errno_t   ecode;
+	lib9p_errno_t   errnum;
 };
 LO_IMPLEMENTATION_H(fmt_formatter, struct lib9p_msg_Rlerror, lib9p_msg_Rlerror);
 
diff --git a/lib9p/include/lib9p/srv.h b/lib9p/include/lib9p/srv.h
index 7ad1b19..85fc6bd 100644
--- a/lib9p/include/lib9p/srv.h
+++ b/lib9p/include/lib9p/srv.h
@@ -138,6 +138,7 @@ struct lib9p_srv {
 	/* Things you provide */
 	void /*TODO*/               (*auth   )(struct lib9p_srv_ctx *, struct lib9p_s treename); /* optional */
 	lo_interface lib9p_srv_file (*rootdir)(struct lib9p_srv_ctx *, struct lib9p_s treename);
+	void                        (*msglog )(struct lib9p_srv_ctx *, enum lib9p_msg_type, void *hostmsg); /* optional */
 
 	/* For internal use */
 	BEGIN_PRIVATE(LIB9P_SRV_H);
diff --git a/lib9p/protogen/c_format.py b/lib9p/protogen/c_format.py
index a1bcbf3..4a809d1 100644
--- a/lib9p/protogen/c_format.py
+++ b/lib9p/protogen/c_format.py
@@ -21,6 +21,19 @@ def bf_numname(typ: idl.Bitfield, num: idl.BitNum, base: str) -> str:
     return c9util.Ident(c9util.add_prefix(prefix, base))
 
 
+def ext_printf(line: str) -> str:
+    assert line.startswith("\t")
+    assert line.endswith("\n")
+    # It sucks that %v trips -Wformat and -Wformat-extra-args
+    # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47781
+    ret = "#pragma GCC diagnostic push\n"
+    ret += '#pragma GCC diagnostic ignored "-Wformat"\n'
+    ret += '#pragma GCC diagnostic ignored "-Wformat-extra-args"\n'
+    ret += line
+    ret += "#pragma GCC diagnostic pop\n"
+    return ret
+
+
 def gen_c_format(versions: set[str], typs: list[idl.UserType]) -> str:
     ret = """
 /* *_format *******************************************************************/
@@ -93,12 +106,9 @@ def gen_c_format(versions: set[str], typs: list[idl.UserType]) -> str:
                     ret += "\t\tfmt_state_putchar(state, '0');\n"
                 ret += "\tfmt_state_putchar(state, ')');\n"
             case idl.Struct(typname="s"):  # SPECIAL(string)
-                ret += "\t/* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47781 */\n"
-                ret += "#pragma GCC diagnostic push\n"
-                ret += '#pragma GCC diagnostic ignored "-Wformat"\n'
-                ret += '#pragma GCC diagnostic ignored "-Wformat-extra-args"\n'
-                ret += '\tfmt_state_printf(state, "%.*q", self->len, self->utf8);\n'
-                ret += "#pragma GCC diagnostic pop\n"
+                ret += ext_printf(
+                    '\tfmt_state_printf(state, "%.*q", self->len, self->utf8);\n'
+                )
             case idl.Struct():  # and idl.Message():
                 if isinstance(typ, idl.Message):
                     ret += f'\tfmt_state_puts(state, "{typ.typname} {{");\n'
@@ -109,15 +119,24 @@ def gen_c_format(versions: set[str], typs: list[idl.UserType]) -> str:
                         continue
                     ret += cutil.ifdef_push(2, c9util.ver_ifdef(member.in_versions))
                     if member.cnt:
-                        if member.typ.static_size == 1:  # SPECIAL (data)
-                            ret += f'\tfmt_state_puts(state, " {member.membname}=<bytedata>");\n'
-                            continue
                         if isinstance(member.cnt, int):
                             cnt_str = str(member.cnt)
                             cnt_typ = "size_t"
                         else:
                             cnt_str = f"self->{member.cnt.membname}"
                             cnt_typ = c9util.typename(member.cnt.typ)
+                        if member.typ.static_size == 1:  # SPECIAL (data)
+                            ret += f"\tif (is_valid_utf8_without_nul((uint8_t *)self->{member.membname}, (size_t){cnt_str})) {{\n"
+                            ret += ext_printf(
+                                f'\t\tfmt_state_printf(state, " {member.membname}=%.*q%s",\n'
+                                f"\t\t\t(int)({cnt_str} < 50 ? {cnt_str} : 50),\n"
+                                f"\t\t\t(char *)self->{member.membname},\n"
+                                f'\t\t\t{cnt_str} < 50 ? "" : "...");\n'
+                            )
+                            ret += "\t} else {\n"
+                            ret += f'\t\tfmt_state_puts(state, " {member.membname}=<bytedata>");\n'
+                            ret += "\t}\n"
+                            continue
                         ret += f'\tfmt_state_puts(state, " {member.membname}=[");\n'
                         ret += f"\tfor ({cnt_typ} i = 0; i < {cnt_str}; i++) {{\n"
                         ret += "\t\tif (i)\n"
diff --git a/lib9p/srv.c b/lib9p/srv.c
index b3b9c4c..ea8b932 100644
--- a/lib9p/srv.c
+++ b/lib9p/srv.c
@@ -160,6 +160,21 @@ struct _lib9p_srv_req {
 
 /* base utilities *************************************************************/
 
+static void msglog(struct _lib9p_srv_req *req, enum lib9p_msg_type typ, void *hostmsg) {
+	struct lib9p_srv *srv = req->parent_sess->parent_conn->parent_srv;
+	if (srv->msglog) {
+		srv->msglog(&req->ctx, typ, hostmsg);
+		return;
+	}
+	/* It sucks that %v trips -Wformat and -Wformat-extra-args
+	 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47781 */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wformat"
+#pragma GCC diagnostic ignored "-Wformat-extra-args"
+	infof("%c %v", typ % 2 ? '<' : '>', lo_box_lib9p_msg_as_fmt_formatter(&req->ctx.basectx, typ, hostmsg));
+#pragma GCC diagnostic pop
+}
+
 #define nonrespond_errorf errorf
 
 static ssize_t write_Rmsg(struct _lib9p_srv_req *req, struct lib9p_Rmsg_send_buf *resp) {
@@ -179,10 +194,10 @@ static void respond_error(struct _lib9p_srv_req *req) {
 	ssize_t r;
 	struct lib9p_msg_Rerror host = {
 		.tag = req->tag,
-		.ename = lib9p_strn(req->ctx.basectx.err_msg,
+		.errstr = lib9p_strn(req->ctx.basectx.err_msg,
 		                    CONFIG_9P_MAX_ERR_SIZE),
 #if CONFIG_9P_ENABLE_9P2000_u
-		.errno = req->ctx.basectx.err_num,
+		.errnum = req->ctx.basectx.err_num,
 #endif
 	};
 
@@ -190,8 +205,8 @@ static void respond_error(struct _lib9p_srv_req *req) {
 
 	/* Truncate the error-string if necessary to avoid needing to
 	 * return LINUX_ERANGE.  */
-	if (((uint32_t)host.ename.len) + sess->rerror_overhead > sess->max_msg_size)
-		host.ename.len = sess->max_msg_size - sess->rerror_overhead;
+	if (((uint32_t)host.errstr.len) + sess->rerror_overhead > sess->max_msg_size)
+		host.errstr.len = sess->max_msg_size - sess->rerror_overhead;
 
 	struct lib9p_Rmsg_send_buf net;
 
@@ -199,11 +214,7 @@ static void respond_error(struct _lib9p_srv_req *req) {
 	                   LIB9P_TYP_Rerror, &host,
 	                   &net);
 
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wformat"
-#pragma GCC diagnostic ignored "-Wformat-extra-args"
-	infof("< %v", lo_box_lib9p_msg_Rerror_as_fmt_formatter(&host));
-#pragma GCC diagnostic pop
+	msglog(req, LIB9P_TYP_Rerror, &host);
 	r = write_Rmsg(req, &net);
 	if (r < 0)
 		nonrespond_errorf("write: %s", net_strerror(-r));
@@ -429,11 +440,7 @@ static void handle_message(struct _lib9p_srv_req *ctx) {
 	enum lib9p_msg_type typ;
 	lib9p_Tmsg_unmarshal(&ctx->ctx.basectx, ctx->net_bytes,
 	                &typ, host_req);
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wformat"
-#pragma GCC diagnostic ignored "-Wformat-extra-args"
-	infof("> %v", lo_box_lib9p_msg_as_fmt_formatter(&ctx->ctx.basectx, typ, host_req));
-#pragma GCC diagnostic pop
+	msglog(ctx, typ, host_req);
 
 	/* Handle it.  */
 	tmessage_handlers[typ](ctx, (void *)host_req, (void *)host_resp);
@@ -447,11 +454,7 @@ static void handle_message(struct _lib9p_srv_req *ctx) {
 		                       typ+1, host_resp,
 		                       &net_resp))
 			goto write;
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wformat"
-#pragma GCC diagnostic ignored "-Wformat-extra-args"
-		infof("< %v", lo_box_lib9p_msg_as_fmt_formatter(&ctx->ctx.basectx, typ+1, &host_resp));
-#pragma GCC diagnostic pop
+		msglog(ctx, typ+1, &host_resp);
 		write_Rmsg(ctx, &net_resp);
 	}
 	if (host_req)
@@ -553,10 +556,13 @@ static inline struct _srv_fidinfo *srv_util_fidsave(struct _lib9p_srv_req *ctx,
 		if (overwrite) {
 			struct srv_pathinfo *old_pathinfo = pathmap_load(&ctx->parent_sess->paths, fidinfo->path);
 			assert(old_pathinfo);
-			if (srv_util_pathisdir(old_pathinfo))
-				LO_CALL(fidinfo->dir.io, iofree);
-			else
-				LO_CALL(fidinfo->file.io, iofree);
+			if (srv_util_pathisdir(old_pathinfo)) {
+				if (!LO_IS_NULL(fidinfo->dir.io))
+					LO_CALL(fidinfo->dir.io, iofree);
+			} else {
+				if (!LO_IS_NULL(fidinfo->file.io))
+					LO_CALL(fidinfo->file.io, iofree);
+			}
 			srv_util_pathfree(ctx, fidinfo->path);
 		} else {
 			lib9p_error(&ctx->ctx.basectx,
@@ -816,13 +822,6 @@ static void handle_Twalk(struct _lib9p_srv_req *ctx,
 		pathinfo = new_pathinfo;
 	}
 	if (resp->nwqid == req->nwname) {
-		if (req->newfid == req->fid) {
-			if (srv_util_pathisdir(pathinfo))
-				LO_CALL(fidinfo->dir.io, iofree);
-			else
-				LO_CALL(fidinfo->file.io, iofree);
-			fidinfo->flags = 0;
-		}
 		if (!srv_util_fidsave(ctx, req->newfid, pathinfo, req->newfid == req->fid))
 			srv_util_pathfree(ctx, LO_CALL(pathinfo->file, qid).path);
 	} else {
diff --git a/lib9p/tests/client_config/config.h b/lib9p/tests/client_config/config.h
new file mode 100644
index 0000000..65ee9de
--- /dev/null
+++ b/lib9p/tests/client_config/config.h
@@ -0,0 +1,40 @@
+/* config.h - Compile-time configuration for lib9p test clients
+ *
+ * Copyright (C) 2024-2025  Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+#ifndef _CONFIG_H_
+#define _CONFIG_H_
+
+/* 9P *************************************************************************/
+
+#define CONFIG_9P_MAX_ERR_SIZE          128
+#define CONFIG_9P_MAX_9P2000_e_WELEM    16
+
+#define CONFIG_9P_ENABLE_9P2000         1 /* bool */
+#define CONFIG_9P_ENABLE_9P2000_u       1 /* bool */
+#define CONFIG_9P_ENABLE_9P2000_e       1 /* bool */
+#define CONFIG_9P_ENABLE_9P2000_L       1 /* bool */
+#define CONFIG_9P_ENABLE_9P2000_p9p     1 /* bool */
+
+/* 9P server (unused) *********************************************************/
+
+#define CONFIG_9P_SRV_MAX_MSG_SIZE      ((4*1024)+24)
+#define CONFIG_9P_SRV_MAX_HOSTMSG_SIZE  CONFIG_9P_SRV_MAX_MSG_SIZE+16
+#define CONFIG_9P_SRV_MAX_FIDS          16
+#define CONFIG_9P_SRV_MAX_REQS          2
+#define CONFIG_9P_SRV_MAX_DEPTH         3
+
+/* COROUTINE (unused) *********************************************************/
+
+#define CONFIG_COROUTINE_STACK_SIZE_DEFAULT    (32*1024)
+#define CONFIG_COROUTINE_NAME_LEN              16
+#define CONFIG_COROUTINE_MEASURE_STACK         1 /* bool */
+#define CONFIG_COROUTINE_PROTECT_STACK         1 /* bool */
+#define CONFIG_COROUTINE_DEBUG                 0 /* bool */
+#define CONFIG_COROUTINE_VALGRIND              1 /* bool */
+#define CONFIG_COROUTINE_GDB                   1 /* bool */
+#define CONFIG_COROUTINE_NUM                   2
+
+#endif /* _CONFIG_H_ */
diff --git a/lib9p/tests/runtest b/lib9p/tests/runtest
index fb66a43..6883391 100755
--- a/lib9p/tests/runtest
+++ b/lib9p/tests/runtest
@@ -1,67 +1,50 @@
 #!/usr/bin/env bash
-# lib9p/tests/runtest - Simple tests for the 9P `test_server`
+# lib9p/tests/runtest - Test harness for the 9P `test_server`
 #
 # Copyright (C) 2025  Luke T. Shumaker <lukeshu@lukeshu.com>
 # SPDX-License-Identifier: AGPL-3.0-or-later
 
 set -euE -o pipefail
-set -x
 
 build_aux=$(realpath --canonicalize-missing -- "${BASH_SOURCE[0]}/../../../build-aux")
 
-port=$(python -c 'import socket; s=socket.socket(); s.bind(("", 0)); print(s.getsockname()[1]); s.close()')
-"${build_aux}/valgrind" ./tests/test_server/test_server "$port" &
-server_pid=$!
-# shellcheck disable=SC2064
-trap "kill $server_pid || true; wait $server_pid || true" EXIT
-server_addr="localhost:${port}"
-
-client=(9p -a "$server_addr")
+if [[ $# != 2 ]]; then
+	echo >&2 "Usage: $0 CLIENTSCRIPT EXPLOG"
+	exit 2
+fi
+clientscript="$1"
+explog="$2"
 
-expect_lines() (
+cleanup=()
+cleanup() {
 	{ set +x; } &>/dev/null
-	printf >&2 '+ diff -u expected.txt actual.txt\n'
-	diff -u <(printf '%s\n' "$@") <(printf '%s\n' "$out")
-)
-
-while [[ -d /proc/$server_pid ]] && ! (readlink /proc/$server_pid/fd/* 2>/dev/null | grep -q ^socket:); do sleep 0.1; done
+	local i
+	for ((i = ${#cleanup[@]} - 1; i >= 0; i--)); do
+		eval "set -x; ${cleanup[$i]}"
+		{ set +x; } &>/dev/null
+	done
+}
+trap cleanup EXIT
 
-out=$("${client[@]}" ls -l '')
-expect_lines \
-	'd-r-xr-xr-x M 0 root root   0 Oct  7  2024 Documentation' \
-	'--r--r--r-- M 0 root root 166 Oct  7  2024 README.md' \
-	'---w--w--w- M 0 root root   0 Oct  7  2024 shutdown'
+logfile=$(mktemp -t lib9p-log.XXXXXXXXXX)
+cleanup+=("rm -f -- ${logfile@Q}")
 
-out=$("${client[@]}" ls -l 'Documentation/')
-expect_lines \
-	'--r--r--r-- M 0 root root 166 Oct  7  2024 x'
-
-out=$("${client[@]}" read 'README.md')
-expect_lines \
-	'<!--' \
-	'  README.md - test static file' \
-	'' \
-	'  Copyright (C) 2024-2025  Luke T. Shumaker <lukeshu@lukeshu.com>' \
-	'  SPDX-License-Identifier: AGPL-3.0-or-later' \
-	'-->' \
-	'Hello, world!'
+port=$(python -c 'import socket; s=socket.socket(); s.bind(("", 0)); print(s.getsockname()[1]); s.close()')
 
-out=$("${client[@]}" read 'Documentation/x')
-expect_lines \
-	'<!--' \
-	'  Documentation/x.txt - test static file' \
-	'' \
-	'  Copyright (C) 2024-2025  Luke T. Shumaker <lukeshu@lukeshu.com>' \
-	'  SPDX-License-Identifier: AGPL-3.0-or-later' \
-	'-->' \
-	'foo'
+set -x
 
-out=$("${client[@]}" stat 'Documentation/x')
-expect_lines \
-	"'x' 'root' 'root' 'root' q (0000000000000001 1 ) m 0444 at 1728337905 mt 1728337904 l 166 t 0 d 0"
+"${build_aux}/valgrind" ./tests/test_server/test_server "$port" "$logfile" &
+server_pid=$!
+cleanup+=("kill $server_pid || true; wait $server_pid || true")
+while [[ -d /proc/$server_pid ]] && ! (readlink /proc/$server_pid/fd/* 2>/dev/null | grep -q ^socket:); do sleep 0.1; done
 
-out=$("${client[@]}" write 'shutdown' <<<1)
-expect_lines ''
+if [[ "$(head -c2 -- "$clientscript")" == '#!' ]]; then
+	"$clientscript" "$port"
+else
+	"${build_aux}/valgrind" "$clientscript" "$port"
+fi
 
 wait "$server_pid"
-trap - EXIT
+cleanup=("${cleanup[@]::1}")
+
+diff -u -- <(grep -e '^[<>]' -- "$explog") "$logfile"
diff --git a/lib9p/tests/test_server/CMakeLists.txt b/lib9p/tests/test_server/CMakeLists.txt
index 19c8edb..eb16165 100644
--- a/lib9p/tests/test_server/CMakeLists.txt
+++ b/lib9p/tests/test_server/CMakeLists.txt
@@ -10,6 +10,7 @@ if (PICO_PLATFORM STREQUAL "host")
 add_library(test_server_objs OBJECT
 	main.c
 	fs_shutdown.c
+	fs_slowread.c
 )
 target_include_directories(test_server_objs PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/config)
 target_include_directories(test_server_objs PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
diff --git a/lib9p/tests/test_server/fs_slowread.c b/lib9p/tests/test_server/fs_slowread.c
new file mode 100644
index 0000000..520edd2
--- /dev/null
+++ b/lib9p/tests/test_server/fs_slowread.c
@@ -0,0 +1,101 @@
+/* lib9p/tests/test_server/fs_slowread.c - slowread API endpoint
+ *
+ * Copyright (C) 2024-2025  Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+#include "fs_slowread.h"
+
+LO_IMPLEMENTATION_C(lib9p_srv_file, struct slowread_file, slowread_file, static);
+
+LO_IMPLEMENTATION_H(lib9p_srv_fio, struct slowread_file, slowread_file);
+LO_IMPLEMENTATION_C(lib9p_srv_fio, struct slowread_file, slowread_file, static);
+
+/* srv_file *******************************************************************/
+
+static void slowread_file_free(struct slowread_file *self) {
+	assert(self);
+}
+static struct lib9p_qid slowread_file_qid(struct slowread_file *self) {
+	assert(self);
+	return (struct lib9p_qid){
+		.type = LIB9P_QT_FILE,
+		.vers = 1,
+		.path = self->pathnum,
+	};
+}
+
+static struct lib9p_stat slowread_file_stat(struct slowread_file *self, struct lib9p_srv_ctx *ctx) {
+	assert(self);
+	assert(ctx);
+	return (struct lib9p_stat){
+		.kern_type                = 0,
+		.kern_dev                 = 0,
+		.file_qid                 = slowread_file_qid(self),
+		.file_mode                = 0444,
+		.file_atime               = UTIL9P_ATIME,
+		.file_mtime               = UTIL9P_MTIME,
+		.file_size                = 6,
+		.file_name                = lib9p_str(self->name),
+		.file_owner_uid           = lib9p_str("root"),
+		.file_owner_gid           = lib9p_str("root"),
+		.file_last_modified_uid   = lib9p_str("root"),
+		.file_extension           = lib9p_str(NULL),
+		.file_owner_n_uid         = 0,
+		.file_owner_n_gid         = 0,
+		.file_last_modified_n_uid = 0,
+	};
+}
+static void slowread_file_wstat(struct slowread_file *self, struct lib9p_srv_ctx *ctx, struct lib9p_stat) {
+	assert(self);
+	assert(ctx);
+	lib9p_error(&ctx->basectx, LINUX_EROFS, "cannot wstat API file");
+}
+static void slowread_file_remove(struct slowread_file *self, struct lib9p_srv_ctx *ctx) {
+	assert(self);
+	assert(ctx);
+	lib9p_error(&ctx->basectx, LINUX_EROFS, "cannot remove API file");
+}
+
+LIB9P_SRV_NOTDIR(struct slowread_file, slowread_file)
+
+static lo_interface lib9p_srv_fio slowread_file_fopen(struct slowread_file *self, struct lib9p_srv_ctx *ctx, bool, bool, bool) {
+	assert(self);
+	assert(ctx);
+	return lo_box_slowread_file_as_lib9p_srv_fio(self);
+}
+
+/* srv_fio ********************************************************************/
+
+static void slowread_file_iofree(struct slowread_file *self) {
+	assert(self);
+}
+
+static uint32_t slowread_file_iounit(struct slowread_file *self) {
+	assert(self);
+	return 0;
+}
+
+static uint32_t slowread_file_pwrite(struct slowread_file *LM_UNUSED(self),
+                                     struct lib9p_srv_ctx *LM_UNUSED(ctx),
+                                     void *LM_UNUSED(buf), uint32_t LM_UNUSED(byte_count),
+                                     uint64_t LM_UNUSED(offset)) {
+	assert_notreached("not writable");
+}
+static void slowread_file_pread(struct slowread_file *self, struct lib9p_srv_ctx *ctx,
+                                uint32_t byte_count, uint64_t LM_UNUSED(byte_offset),
+                                struct iovec *ret) {
+	assert(self);
+	assert(ctx);
+	assert(ret);
+
+	while (!lib9p_srv_flush_requested(ctx))
+		cr_yield();
+	if (self->flushable)
+		lib9p_srv_acknowledge_flush(ctx);
+	else
+		*ret = (struct iovec){
+			.iov_base = "Sloth\n",
+			.iov_len = 6 < byte_count ? 6 : byte_count,
+		};
+}
diff --git a/lib9p/tests/test_server/fs_slowread.h b/lib9p/tests/test_server/fs_slowread.h
new file mode 100644
index 0000000..ef4b65f
--- /dev/null
+++ b/lib9p/tests/test_server/fs_slowread.h
@@ -0,0 +1,22 @@
+/* lib9p/tests/test_server/fs_slowread.h - slowread API endpoint
+ *
+ * Copyright (C) 2024-2025  Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+#ifndef _LIB9P_TESTS_TEST_SERVER_FS_SLOWREAD_H_
+#define _LIB9P_TESTS_TEST_SERVER_FS_SLOWREAD_H_
+
+#include <util9p/static.h>
+#include <libhw/host_net.h>
+
+struct slowread_file {
+	char            *name;
+	uint64_t         pathnum;
+
+	bool            flushable;
+};
+LO_IMPLEMENTATION_H(lib9p_srv_file, struct slowread_file, slowread_file);
+#define lo_box_slowread_file_as_lib9p_srv_file(obj) util9p_box(slowread_file, obj)
+
+#endif /* _LIB9P_TESTS_TEST_SERVER_FS_SLOWREAD_H_ */
diff --git a/lib9p/tests/test_server/main.c b/lib9p/tests/test_server/main.c
index 8d22a04..2743629 100644
--- a/lib9p/tests/test_server/main.c
+++ b/lib9p/tests/test_server/main.c
@@ -5,6 +5,8 @@
  */
 
 #include <error.h>
+#include <errno.h>
+#include <stdio.h>
 #include <stdlib.h> /* for atoi() */
 
 #include <lib9p/srv.h>
@@ -18,6 +20,7 @@
 
 #include "static.h"
 #include "fs_shutdown.h"
+#include "fs_slowread.h"
 
 /* configuration **************************************************************/
 
@@ -37,6 +40,7 @@ struct {
 	uint16_t                        port;
 	struct hostnet_tcp_listener     listeners[CONFIG_SRV9P_NUM_CONNS];
 	struct lib9p_srv                srv;
+	FILE                           *logstream;
 } globals = {
 	.srv = (struct lib9p_srv){
 		.rootdir = get_root,
@@ -45,32 +49,33 @@ struct {
 
 /* file tree ******************************************************************/
 
-enum { PATH_BASE = __COUNTER__ };
-#define PATH_COUNTER __COUNTER__ - PATH_BASE
-
-#define STATIC_FILE(STRNAME, SYMNAME)                                      \
-	UTIL9P_STATIC_FILE(PATH_COUNTER, STRNAME,                          \
+#define STATIC_FILE(N, STRNAME, SYMNAME)                                   \
+	UTIL9P_STATIC_FILE(N, STRNAME,                                     \
 	                   .data_start = _binary_static_##SYMNAME##_start, \
 	                   .data_end   = _binary_static_##SYMNAME##_end)
-#define STATIC_DIR(STRNAME, ...)  \
-	UTIL9P_STATIC_DIR(PATH_COUNTER, STRNAME, __VA_ARGS__)
+#define STATIC_DIR(N, STRNAME, ...) \
+	UTIL9P_STATIC_DIR(N, STRNAME, __VA_ARGS__)
 
-#define API_FILE(STRNAME, SYMNAME, ...)                                      \
+#define API_FILE(N, STRNAME, SYMNAME, ...)                                   \
 	lo_box_##SYMNAME##_file_as_lib9p_srv_file(&((struct SYMNAME##_file){ \
 		.name = STRNAME,                                             \
-		.pathnum = PATH_COUNTER                                      \
+		.pathnum = N                                                 \
 		__VA_OPT__(,) __VA_ARGS__                                    \
 	}))
 
 struct lib9p_srv_file root =
-		STATIC_DIR("",
-		           STATIC_DIR("Documentation",
-		                      STATIC_FILE("x", Documentation_x_txt),
+		STATIC_DIR(1, "",
+		           STATIC_DIR(2, "Documentation",
+		                      STATIC_FILE(3, "x", Documentation_x_txt),
 		                      ),
-		           STATIC_FILE("README.md", README_md),
-		           API_FILE("shutdown", shutdown,
+		           STATIC_FILE(4, "README.md", README_md),
+		           API_FILE(5, "shutdown", shutdown,
 		                   .listeners = globals.listeners,
 		                   .nlisteners = LM_ARRAY_LEN(globals.listeners)),
+		           API_FILE(6, "slowread", slowread,
+		                    .flushable = false),
+		           API_FILE(7, "slowread-flushable", slowread,
+		                    .flushable = true),
 		           );
 
 static lo_interface lib9p_srv_file get_root(struct lib9p_srv_ctx *LM_UNUSED(ctx), struct lib9p_s LM_UNUSED(treename)) {
@@ -109,15 +114,41 @@ static COROUTINE init_cr(void *) {
 	cr_exit();
 }
 
+static void log_fct(char character, void *_stream) {
+	FILE *stream = _stream;
+	putc(character, stream);
+	putchar(character);
+}
+
+static void log_msg(struct lib9p_srv_ctx *ctx, enum lib9p_msg_type typ, void *hostmsg) {
+	/* It sucks that %v trips -Wformat and -Wformat-extra-args
+	 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47781 */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wformat"
+#pragma GCC diagnostic ignored "-Wformat-extra-args"
+	fmt_fctprintf(log_fct, globals.logstream,
+	              "%c %v\n", typ % 2 ? '<' : '>',
+	              lo_box_lib9p_msg_as_fmt_formatter(&ctx->basectx, typ, hostmsg));
+#pragma GCC diagnostic pop
+	fflush(globals.logstream);
+}
+
 int main(int argc, char *argv[]) {
-	if (argc != 2)
-		error(2, 0, "usage: %s PORT_NUMBER", argv[0]);
+	if (argc != 3)
+		error(2, 0, "usage: %s PORT_NUMBER LOGFILE", argv[0]);
+
 	globals.port = atoi(argv[1]);
+	globals.logstream = fopen(argv[2], "w");
+	if (!globals.logstream)
+		error(2, errno, "fopen");
+	globals.srv.msglog = log_msg;
+
 	struct hostclock clock_monotonic = {
 		.clock_id = CLOCK_MONOTONIC,
 	};
 	bootclock = lo_box_hostclock_as_alarmclock(&clock_monotonic);
 	coroutine_add("init", init_cr, NULL);
 	coroutine_main();
+	fclose(globals.logstream);
 	return 0;
 }
diff --git a/lib9p/tests/testclient-p9p b/lib9p/tests/testclient-p9p
new file mode 100755
index 0000000..81a7e50
--- /dev/null
+++ b/lib9p/tests/testclient-p9p
@@ -0,0 +1,61 @@
+#!/usr/bin/env bash
+# lib9p/tests/testclient-p9p - Test the 9P `test_server` against Plan 9 Port's `9p` utility
+#
+# Copyright (C) 2025  Luke T. Shumaker <lukeshu@lukeshu.com>
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+set -euE -o pipefail
+
+if [[ $# != 1 ]]; then
+	echo >&2 "Usage: $0 SERVER_PORT"
+	echo >&2 "Usage: ./runtest $0 EXPLOG"
+	exit 2
+fi
+
+expect_lines() (
+	{ set +x; } &>/dev/null
+	printf >&2 '+ diff -u expected.txt actual.txt\n'
+	diff -u <(printf '%s\n' "$@") <(printf '%s\n' "$out")
+)
+
+set -x
+client=(9p -a "localhost:${1}")
+
+out=$("${client[@]}" ls -l '')
+expect_lines \
+	'd-r-xr-xr-x M 0 root root   0 Oct  7  2024 Documentation' \
+	'--r--r--r-- M 0 root root 166 Oct  7  2024 README.md' \
+	'---w--w--w- M 0 root root   0 Oct  7  2024 shutdown' \
+	'--r--r--r-- M 0 root root   6 Oct  7  2024 slowread' \
+	'--r--r--r-- M 0 root root   6 Oct  7  2024 slowread-flushable'
+
+out=$("${client[@]}" ls -l 'Documentation/')
+expect_lines \
+	'--r--r--r-- M 0 root root 166 Oct  7  2024 x'
+
+out=$("${client[@]}" read 'README.md')
+expect_lines \
+	'<!--' \
+	'  README.md - test static file' \
+	'' \
+	'  Copyright (C) 2024-2025  Luke T. Shumaker <lukeshu@lukeshu.com>' \
+	'  SPDX-License-Identifier: AGPL-3.0-or-later' \
+	'-->' \
+	'Hello, world!'
+
+out=$("${client[@]}" read 'Documentation/x')
+expect_lines \
+	'<!--' \
+	'  Documentation/x.txt - test static file' \
+	'' \
+	'  Copyright (C) 2024-2025  Luke T. Shumaker <lukeshu@lukeshu.com>' \
+	'  SPDX-License-Identifier: AGPL-3.0-or-later' \
+	'-->' \
+	'foo'
+
+out=$("${client[@]}" stat 'Documentation/x')
+expect_lines \
+	"'x' 'root' 'root' 'root' q (0000000000000003 1 ) m 0444 at 1728337905 mt 1728337904 l 166 t 0 d 0"
+
+out=$("${client[@]}" write 'shutdown' <<<1)
+expect_lines ''
diff --git a/lib9p/tests/testclient-p9p.explog b/lib9p/tests/testclient-p9p.explog
new file mode 100644
index 0000000..3bfb0b0
--- /dev/null
+++ b/lib9p/tests/testclient-p9p.explog
@@ -0,0 +1,106 @@
+# lib9p/tests/testclient-p9p.explog - Expected 9P logfile of testclient-p9p
+#
+# Copyright (C) 2025  Luke T. Shumaker <lukeshu@lukeshu.com>
+# SPDX-License-Identifier: AGPL-3.0-or-later
+> Tversion { tag=NOTAG max_msg_size=8192 version="9P2000" }
+< Rversion { tag=NOTAG max_msg_size=4120 version="9P2000" }
+> Tauth { tag=0 afid=0 uname="lukeshu" aname="" n_uid=0 }
+< Rerror { tag=0 errstr="authentication not required" errnum=95 }
+> Tattach { tag=0 fid=0 afid=NOFID uname="lukeshu" aname="" n_uid=0 }
+< Rattach { tag=0 qid={ type=(DIR) vers=1 path=1 } }
+> Twalk { tag=0 fid=0 newfid=1 nwname=0 wname=[ ] }
+< Rwalk { tag=0 nwqid=0 wqid=[ ] }
+> Tstat { tag=0 fid=1 }
+< Rstat { tag=0 stat={ kern_type=0 kern_dev=0 file_qid={ type=(DIR) vers=1 path=1 } file_mode=(DIR|0555) file_atime=1728337905 file_mtime=1728337904 file_size=0 file_name="" file_owner_uid="root" file_owner_gid="root" file_last_modified_uid="root" file_extension="" file_owner_n_uid=0 file_owner_n_gid=0 file_last_modified_n_uid=0 } }
+> Tclunk { tag=0 fid=1 }
+< Rclunk { tag=0 }
+> Twalk { tag=0 fid=0 newfid=1 nwname=0 wname=[ ] }
+< Rwalk { tag=0 nwqid=0 wqid=[ ] }
+> Topen { tag=0 fid=1 mode=(MODE_READ) }
+< Ropen { tag=0 qid={ type=(DIR) vers=1 path=1 } iounit=0 }
+> Tread { tag=0 fid=1 offset=0 count=4096 }
+< Rread { tag=0 count=361 data=<bytedata> }
+> Tread { tag=0 fid=1 offset=361 count=4096 }
+< Rread { tag=0 count=0 data="" }
+> Tclunk { tag=0 fid=1 }
+< Rclunk { tag=0 }
+> Tversion { tag=NOTAG max_msg_size=8192 version="9P2000" }
+< Rversion { tag=NOTAG max_msg_size=4120 version="9P2000" }
+> Tauth { tag=0 afid=0 uname="lukeshu" aname="" n_uid=0 }
+< Rerror { tag=0 errstr="authentication not required" errnum=95 }
+> Tattach { tag=0 fid=0 afid=NOFID uname="lukeshu" aname="" n_uid=0 }
+< Rattach { tag=0 qid={ type=(DIR) vers=1 path=1 } }
+> Twalk { tag=0 fid=0 newfid=1 nwname=1 wname=["Documentation" ] }
+< Rwalk { tag=0 nwqid=1 wqid=[{ type=(DIR) vers=1 path=2 } ] }
+> Tstat { tag=0 fid=1 }
+< Rstat { tag=0 stat={ kern_type=0 kern_dev=0 file_qid={ type=(DIR) vers=1 path=2 } file_mode=(DIR|0555) file_atime=1728337905 file_mtime=1728337904 file_size=0 file_name="Documentation" file_owner_uid="root" file_owner_gid="root" file_last_modified_uid="root" file_extension="" file_owner_n_uid=0 file_owner_n_gid=0 file_last_modified_n_uid=0 } }
+> Tclunk { tag=0 fid=1 }
+< Rclunk { tag=0 }
+> Twalk { tag=0 fid=0 newfid=1 nwname=1 wname=["Documentation" ] }
+< Rwalk { tag=0 nwqid=1 wqid=[{ type=(DIR) vers=1 path=2 } ] }
+> Topen { tag=0 fid=1 mode=(MODE_READ) }
+< Ropen { tag=0 qid={ type=(DIR) vers=1 path=2 } iounit=0 }
+> Tread { tag=0 fid=1 offset=0 count=4096 }
+< Rread { tag=0 count=62 data=<bytedata> }
+> Tread { tag=0 fid=1 offset=62 count=4096 }
+< Rread { tag=0 count=0 data="" }
+> Tclunk { tag=0 fid=1 }
+< Rclunk { tag=0 }
+> Tversion { tag=NOTAG max_msg_size=8192 version="9P2000" }
+< Rversion { tag=NOTAG max_msg_size=4120 version="9P2000" }
+> Tauth { tag=0 afid=0 uname="lukeshu" aname="" n_uid=0 }
+< Rerror { tag=0 errstr="authentication not required" errnum=95 }
+> Tattach { tag=0 fid=0 afid=NOFID uname="lukeshu" aname="" n_uid=0 }
+< Rattach { tag=0 qid={ type=(DIR) vers=1 path=1 } }
+> Twalk { tag=0 fid=0 newfid=1 nwname=1 wname=["README.md" ] }
+< Rwalk { tag=0 nwqid=1 wqid=[{ type=(0) vers=1 path=4 } ] }
+> Topen { tag=0 fid=1 mode=(MODE_READ) }
+< Ropen { tag=0 qid={ type=(0) vers=1 path=4 } iounit=0 }
+> Tread { tag=0 fid=1 offset=0 count=4096 }
+< Rread { tag=0 count=166 data="<!--\n  README.md - test static file\n\n  Copyright ("... }
+> Tread { tag=0 fid=1 offset=166 count=4096 }
+< Rread { tag=0 count=0 data="" }
+> Tclunk { tag=0 fid=1 }
+< Rclunk { tag=0 }
+> Tversion { tag=NOTAG max_msg_size=8192 version="9P2000" }
+< Rversion { tag=NOTAG max_msg_size=4120 version="9P2000" }
+> Tauth { tag=0 afid=0 uname="lukeshu" aname="" n_uid=0 }
+< Rerror { tag=0 errstr="authentication not required" errnum=95 }
+> Tattach { tag=0 fid=0 afid=NOFID uname="lukeshu" aname="" n_uid=0 }
+< Rattach { tag=0 qid={ type=(DIR) vers=1 path=1 } }
+> Twalk { tag=0 fid=0 newfid=1 nwname=2 wname=["Documentation", "x" ] }
+< Rwalk { tag=0 nwqid=2 wqid=[{ type=(DIR) vers=1 path=2 }, { type=(0) vers=1 path=3 } ] }
+> Topen { tag=0 fid=1 mode=(MODE_READ) }
+< Ropen { tag=0 qid={ type=(0) vers=1 path=3 } iounit=0 }
+> Tread { tag=0 fid=1 offset=0 count=4096 }
+< Rread { tag=0 count=166 data="<!--\n  Documentation/x.txt - test static file\n\n  C"... }
+> Tread { tag=0 fid=1 offset=166 count=4096 }
+< Rread { tag=0 count=0 data="" }
+> Tclunk { tag=0 fid=1 }
+< Rclunk { tag=0 }
+> Tversion { tag=NOTAG max_msg_size=8192 version="9P2000" }
+< Rversion { tag=NOTAG max_msg_size=4120 version="9P2000" }
+> Tauth { tag=0 afid=0 uname="lukeshu" aname="" n_uid=0 }
+< Rerror { tag=0 errstr="authentication not required" errnum=95 }
+> Tattach { tag=0 fid=0 afid=NOFID uname="lukeshu" aname="" n_uid=0 }
+< Rattach { tag=0 qid={ type=(DIR) vers=1 path=1 } }
+> Twalk { tag=0 fid=0 newfid=1 nwname=2 wname=["Documentation", "x" ] }
+< Rwalk { tag=0 nwqid=2 wqid=[{ type=(DIR) vers=1 path=2 }, { type=(0) vers=1 path=3 } ] }
+> Tstat { tag=0 fid=1 }
+< Rstat { tag=0 stat={ kern_type=0 kern_dev=0 file_qid={ type=(0) vers=1 path=3 } file_mode=(0444) file_atime=1728337905 file_mtime=1728337904 file_size=166 file_name="x" file_owner_uid="root" file_owner_gid="root" file_last_modified_uid="root" file_extension="" file_owner_n_uid=0 file_owner_n_gid=0 file_last_modified_n_uid=0 } }
+> Tclunk { tag=0 fid=1 }
+< Rclunk { tag=0 }
+> Tversion { tag=NOTAG max_msg_size=8192 version="9P2000" }
+< Rversion { tag=NOTAG max_msg_size=4120 version="9P2000" }
+> Tauth { tag=0 afid=0 uname="lukeshu" aname="" n_uid=0 }
+< Rerror { tag=0 errstr="authentication not required" errnum=95 }
+> Tattach { tag=0 fid=0 afid=NOFID uname="lukeshu" aname="" n_uid=0 }
+< Rattach { tag=0 qid={ type=(DIR) vers=1 path=1 } }
+> Twalk { tag=0 fid=0 newfid=1 nwname=1 wname=["shutdown" ] }
+< Rwalk { tag=0 nwqid=1 wqid=[{ type=(0) vers=1 path=5 } ] }
+> Topen { tag=0 fid=1 mode=(TRUNC|MODE_WRITE) }
+< Ropen { tag=0 qid={ type=(0) vers=1 path=5 } iounit=0 }
+> Twrite { tag=0 fid=1 offset=0 count=2 data="1\n" }
+< Rwrite { tag=0 count=2 }
+> Tclunk { tag=0 fid=1 }
+< Rclunk { tag=0 }
diff --git a/lib9p/tests/testclient-sess.c b/lib9p/tests/testclient-sess.c
new file mode 100644
index 0000000..423dc2c
--- /dev/null
+++ b/lib9p/tests/testclient-sess.c
@@ -0,0 +1,144 @@
+/* lib9p/tests/testclient-sess.c - Test the 9P `test_server`'s sessions
+ *
+ * Copyright (C) 2025  Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+#include <arpa/inet.h> /* for htons(), inet_addr() */
+#include <errno.h>
+#include <error.h>
+#include <netinet/in.h> /* for struct sockaddr{,_in} */
+#include <stdlib.h> /* for atoi() */
+#include <sys/socket.h> /* for socket(), connect() */
+#include <sys/uio.h> /* for writev() */
+#include <unistd.h> /* for read() */
+
+#include <libmisc/assert.h>
+#include <libmisc/endian.h>
+#include <lib9p/9p.h>
+
+#define MAX_MSG_SIZE (8*1024)
+
+static void _send9p(int fd, struct lib9p_ctx *ctx, enum lib9p_msg_type typ, void *body) {
+	struct lib9p_Tmsg_send_buf buf;
+	bool err = lib9p_Tmsg_marshal(ctx, typ, body, &buf);
+	assert(!err);
+	size_t exp = 0;
+	for (size_t i = 0; i < buf.iov_cnt; i++)
+		exp += buf.iov[i].iov_len;
+	ssize_t act = writev(fd, buf.iov, buf.iov_cnt);
+	if (act < 0)
+		error(1, errno, "writev");
+	assert((size_t)act == exp);
+}
+
+#define send9p(typ, ...) _send9p(fd, &ctx, LIB9P_TYP_##typ, &((struct lib9p_msg_##typ){ __VA_ARGS__ }))
+
+static void _recv9p(int fd) {
+	uint8_t buf[MAX_MSG_SIZE];
+	size_t goal = 4;
+	size_t done = 0;
+	while (done < goal) {
+		ssize_t n = read(fd, &buf[done], goal-done);
+		if (n < 0)
+			error(1, errno, "read");
+		done += n;
+	}
+	goal = uint32le_decode(buf);
+	assert(goal <= MAX_MSG_SIZE);
+	while (done < goal) {
+		ssize_t n = read(fd, &buf[done], goal-done);
+		if (n < 0)
+			error(1, errno, "read");
+		done += n;
+	}
+}
+
+#define recv9p() _recv9p(fd)
+
+int main(int argc, char *argv[]) {
+	if (argc != 2)
+		error(2, 0, "Usage: %s SERVER_PORT", argv[0]);
+	uint16_t server_port = atoi(argv[1]);
+
+	union {
+                struct sockaddr         gen;
+                struct sockaddr_in      in;
+	} server_addr = {};
+	server_addr.in.sin_family = AF_INET;
+	server_addr.in.sin_addr.s_addr = inet_addr("127.0.0.1");
+	server_addr.in.sin_port = htons(server_port);
+
+	int fd = socket(AF_INET, SOCK_STREAM, 0);
+	if (fd < 0)
+		error(1, errno, "socket");
+	if (connect(fd, &server_addr.gen, sizeof(server_addr)) < 0)
+		error(1, errno, "connect");
+
+	struct lib9p_ctx ctx = {
+		.max_msg_size = 16*1024,
+	};
+
+	struct lib9p_s wname[1];
+
+	/* numeric downgrade, unknown ext *************************************/
+	send9p(Tversion, .tag=0, .max_msg_size=57, .version=lib9p_str("9P2025.x"));
+	recv9p(); /* Rversion */
+	ctx.version = LIB9P_VER_9P2000;
+
+	/* numeric downgrade, known ext ***************************************/
+	send9p(Tversion, .tag=0, .max_msg_size=57, .version=lib9p_str("9P2025.u"));
+	recv9p(); /* Rversion */
+	ctx.version = LIB9P_VER_9P2000_u;
+
+	/* ext version ********************************************************/
+	send9p(Tversion, .tag=0, .max_msg_size=57, .version=lib9p_str("9P2000.u"));
+	recv9p(); /* Rversion */
+	ctx.version = LIB9P_VER_9P2000_u;
+
+	/* main session *******************************************************/
+	send9p(Tversion, .tag=0, .max_msg_size=(8*1024), .version=lib9p_str("9P2000"));
+	recv9p(); /* Rversion */
+	ctx.version = LIB9P_VER_9P2000;
+	send9p(Tattach, .tag=0, .fid=0, .afid=LIB9P_FID_NOFID, .uname=lib9p_str("nobody"), .aname=lib9p_str(""));
+	recv9p(); /* Rattach */
+
+	/* flush, but original response comes back first */
+	wname[0] = lib9p_str("slowread"); send9p(Twalk, .tag=0, .fid=0, .newfid=1, .nwname=1, .wname=wname);
+	recv9p(); /* Rwalk */
+	send9p(Topen, .tag=0, .fid=1, .mode=LIB9P_O_MODE_READ);
+	recv9p(); /* Ropen */
+	send9p(Tread, .tag=1, .fid=1, .offset=0, .count=6);
+	send9p(Tflush, .tag=2, .oldtag=1);
+	recv9p(); /* Rread */
+	recv9p(); /* Rflush */
+
+	/* flush, original request is aborted with error */
+	wname[0] = lib9p_str("slowread-flushable"); send9p(Twalk, .tag=1, .fid=0, .newfid=2, .nwname=1, .wname=wname);
+	recv9p(); /* Rwalk */
+	send9p(Topen, .tag=0, .fid=2, .mode=LIB9P_O_MODE_READ);
+	recv9p(); /* Ropen */
+	send9p(Tread, .tag=1, .fid=2, .offset=0, .count=6);
+	send9p(Tflush, .tag=2, .oldtag=1);
+	recv9p(); /* Rerror */
+	recv9p(); /* Rflush */
+
+	/* flush, unknown tag */
+	send9p(Tflush, .tag=0, .oldtag=99);
+	recv9p(); /* Rflush */
+
+	/* shutdown ***********************************************************/
+	send9p(Tversion, .tag=0, .max_msg_size=(8*1024), .version=lib9p_str("9P2000"));
+	recv9p(); /* Rversion */
+	ctx.version = LIB9P_VER_9P2000;
+	send9p(Tattach, .tag=0, .fid=0, .afid=LIB9P_FID_NOFID, .uname=lib9p_str("nobody"), .aname=lib9p_str(""));
+	recv9p(); /* Rattach */
+	/* check the newfid==fid case */
+	wname[0] = lib9p_str("shutdown"); send9p(Twalk, .tag=0, .fid=0, .newfid=0, .nwname=1, .wname=wname);
+	recv9p(); /* Rwalk */
+	send9p(Topen, .tag=0, .fid=0, .mode=LIB9P_O_MODE_WRITE);
+	recv9p(); /* Ropen */
+	send9p(Twrite, .tag=0, .fid=0, .offset=0, .count=2, .data="1\n");
+	recv9p(); /* Rwrite */
+	return 0;
+}
diff --git a/lib9p/tests/testclient-sess.explog b/lib9p/tests/testclient-sess.explog
new file mode 100644
index 0000000..b1f3085
--- /dev/null
+++ b/lib9p/tests/testclient-sess.explog
@@ -0,0 +1,58 @@
+# lib9p/tests/testclient-sess.explog - Expected 9P logfile of testclient-sess.c
+#
+# Copyright (C) 2025  Luke T. Shumaker <lukeshu@lukeshu.com>
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+# numeric downgrade, unknown ext ###############################################
+> Tversion { tag=0 max_msg_size=57 version="9P2025.x" }
+< Rversion { tag=0 max_msg_size=57 version="9P2000" }
+
+# numeric downgrade, known ext #################################################
+> Tversion { tag=0 max_msg_size=57 version="9P2025.u" }
+< Rversion { tag=0 max_msg_size=57 version="9P2000.u" }
+
+# ext version ##################################################################
+> Tversion { tag=0 max_msg_size=57 version="9P2000.u" }
+< Rversion { tag=0 max_msg_size=57 version="9P2000.u" }
+
+# main session #################################################################
+> Tversion { tag=0 max_msg_size=8192 version="9P2000" }
+< Rversion { tag=0 max_msg_size=4120 version="9P2000" }
+> Tattach { tag=0 fid=0 afid=NOFID uname="nobody" aname="" n_uid=0 }
+< Rattach { tag=0 qid={ type=(DIR) vers=1 path=1 } }
+
+# flush, but original response comes back first
+> Twalk { tag=0 fid=0 newfid=1 nwname=1 wname=["slowread" ] }
+< Rwalk { tag=0 nwqid=1 wqid=[{ type=(0) vers=1 path=6 } ] }
+> Topen { tag=0 fid=1 mode=(MODE_READ) }
+< Ropen { tag=0 qid={ type=(0) vers=1 path=6 } iounit=0 }
+> Tread { tag=1 fid=1 offset=0 count=6 }
+> Tflush { tag=2 oldtag=1 }
+< Rread { tag=1 count=6 data="Sloth\n" }
+< Rflush { tag=2 }
+
+# flush, succeeds
+> Twalk { tag=1 fid=0 newfid=2 nwname=1 wname=["slowread-flushable" ] }
+< Rwalk { tag=1 nwqid=1 wqid=[{ type=(0) vers=1 path=7 } ] }
+> Topen { tag=0 fid=2 mode=(MODE_READ) }
+< Ropen { tag=0 qid={ type=(0) vers=1 path=7 } iounit=0 }
+> Tread { tag=1 fid=2 offset=0 count=6 }
+> Tflush { tag=2 oldtag=1 }
+< Rflush { tag=2 }
+< Rerror { tag=1 errstr="request canceled by flush" errnum=125 }
+
+# flush, unknown tag
+> Tflush { tag=0 oldtag=99 }
+< Rflush { tag=0 }
+
+# shutdown #####################################################################
+> Tversion { tag=0 max_msg_size=8192 version="9P2000" }
+< Rversion { tag=0 max_msg_size=4120 version="9P2000" }
+> Tattach { tag=0 fid=0 afid=NOFID uname="nobody" aname="" n_uid=0 }
+< Rattach { tag=0 qid={ type=(DIR) vers=1 path=1 } }
+> Twalk { tag=0 fid=0 newfid=0 nwname=1 wname=["shutdown" ] }
+< Rwalk { tag=0 nwqid=1 wqid=[{ type=(0) vers=1 path=5 } ] }
+> Topen { tag=0 fid=0 mode=(MODE_WRITE) }
+< Ropen { tag=0 qid={ type=(0) vers=1 path=5 } iounit=0 }
+> Twrite { tag=0 fid=0 offset=0 count=2 data="1\n" }
+< Rwrite { tag=0 count=2 }