fix(wasmtime): avoid crash during Nginx reload (#120)

Signed-off-by: spacewander <[email protected]>

Author: spacewander

src/vm/wasmtime.c

@@ -22,6 +22,7 @@
 
 
 typedef struct {
+    wasm_engine_t           *vm_engine;
     wasmtime_module_t       *module;
     wasmtime_store_t        *store;
     wasmtime_context_t      *context;
@@ -32,7 +33,6 @@ typedef struct {
 
 
 static ngx_str_t      vm_name = ngx_string("wasmtime");
-static wasm_engine_t *vm_engine;
 static wasmtime_val_t   param_int32[1] = {{ .kind = WASMTIME_I32 }};
 static wasmtime_val_t   param_int32_int32[2] = {{ .kind = WASMTIME_I32 }, { .kind = WASMTIME_I32 }};
 static wasmtime_val_t   param_int32_int32_int32[3] = {
@@ -96,24 +96,14 @@ ngx_wasm_wasmtime_init(void)
 {
     ngx_log_error(NGX_LOG_NOTICE, ngx_cycle->log, 0, "init wasm vm: wasmtime");
 
-    vm_engine = wasm_engine_new();
-    if (vm_engine == NULL) {
-        return NGX_DECLINED;
-    }
-
     return NGX_OK;
 }
 
 
 static void
 ngx_wasm_wasmtime_cleanup(void)
 {
-    if (vm_engine == NULL) {
-        return;
-    }
-
     ngx_log_error(NGX_LOG_NOTICE, ngx_cycle->log, 0, "cleanup wasm vm: wasmtime");
-    wasm_engine_delete(vm_engine);
 }
 
 
@@ -122,6 +112,7 @@ ngx_wasm_wasmtime_load(const char *bytecode, size_t size)
 {
     size_t                        i;
     bool                          ok;
+    wasm_engine_t                *vm_engine;
     wasm_trap_t                  *trap = NULL;
     wasmtime_module_t            *module;
     wasmtime_store_t             *store;
@@ -132,10 +123,16 @@ ngx_wasm_wasmtime_load(const char *bytecode, size_t size)
     ngx_wasm_wasmtime_plugin_t   *plugin;
     wasmtime_extern_t             item;
 
+    vm_engine = wasm_engine_new();
+    if (vm_engine == NULL) {
+        ngx_log_error(NGX_LOG_ERR, ngx_cycle->log, 0, "failed to new engine");
+        return NULL;
+    }
+
     error = wasmtime_module_new(vm_engine, (const uint8_t*) bytecode, size, &module);
     if (error != NULL) {
         ngx_wasm_wasmtime_report_error(ngx_cycle->log, "failed to new module: ", error, NULL);
-        return NULL;
+        goto free_engine;
     }
 
     store = wasmtime_store_new(vm_engine, NULL, NULL);
@@ -215,6 +212,7 @@ ngx_wasm_wasmtime_load(const char *bytecode, size_t size)
     plugin->memory = item.of.memory;
 
 
+    plugin->vm_engine = vm_engine;
     plugin->module = module;
     plugin->store = store;
     plugin->context = context;
@@ -236,6 +234,9 @@ ngx_wasm_wasmtime_load(const char *bytecode, size_t size)
 free_module:
     wasmtime_module_delete(module);
 
+free_engine:
+    wasm_engine_delete(vm_engine);
+
     return NULL;
 }
 
@@ -248,6 +249,7 @@ ngx_wasm_wasmtime_unload(void *data)
     wasmtime_module_delete(plugin->module);
     wasmtime_store_delete(plugin->store);
     wasmtime_linker_delete(plugin->linker);
+    wasm_engine_delete(plugin->vm_engine);
 
     ngx_free(plugin);
 

t/hup.t

@@ -0,0 +1,69 @@
+# Copyright 2022 Shenzhen ZhiLiu Technology Co., Ltd.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+BEGIN {
+    $ENV{TEST_NGINX_USE_HUP} = 1;
+}
+
+use t::WASM 'no_plan';
+
+run_tests();
+
+__DATA__
+
+=== TEST 1: sanity
+--- http_config
+    init_worker_by_lua_block {
+        local wasm = require("resty.proxy-wasm")
+        local p = wasm.load("plugin", "t/testdata/log/main.go.wasm")
+        wasm.on_configure(p, "blah")
+    }
+--- grep_error_log eval
+qr/\[\w+\] \d+#\d+: ouch, something is wrong/
+--- grep_error_log_out eval
+qr/\[emerg\] \d+#\d+: ouch, something is wrong
+\[error\] \d+#\d+: ouch, something is wrong
+\[warn\] \d+#\d+: ouch, something is wrong
+\[info\] \d+#\d+: ouch, something is wrong
+/
+--- config
+    location /t {
+        return 200;
+    }
+--- no_error_log
+[alert]
+
+
+
+=== TEST 2: after receiving SIGHUP
+--- http_config
+    init_worker_by_lua_block {
+        local wasm = require("resty.proxy-wasm")
+        local p = wasm.load("plugin", "t/testdata/log/main.go.wasm")
+        wasm.on_configure(p, "blah")
+    }
+--- grep_error_log eval
+qr/\[\w+\] \d+#\d+: ouch, something is wrong/
+--- grep_error_log_out eval
+qr/\[emerg\] \d+#\d+: ouch, something is wrong
+\[error\] \d+#\d+: ouch, something is wrong
+\[warn\] \d+#\d+: ouch, something is wrong
+\[info\] \d+#\d+: ouch, something is wrong
+/
+--- config
+    location /t {
+        return 200;
+    }
+--- no_error_log
+[alert]