Refactor of process management.

The process abstraction has changed to:

  setup(task, process)
  start(task, process_data)
  prefork(task, process, mp)

The prefork() occurs in the main process right before fork.

The file src/nxt_main_process.c is completely free of process
specific logic.

The creation of a process now supports a PROCESS_CREATED state.  The
The setup() function of each process can set its state to either
created or ready.  If created, a MSG_PROCESS_CREATED is sent to main
process, where external setup can be done (required for rootfs under
container).

The core processes (discovery, controller and router) doesn't need
external setup, then they all proceeds to their start() function
straight away.

In the case of applications, the load of the module happens at the
process setup() time and The module's init() function has changed
to be the start() of the process.

The module API has changed to:

  setup(task, process, conf)
  start(task, data)

As a direct benefit of the PROCESS_CREATED message, the clone(2) of
processes using pid namespaces now doesn't need to create a pipe
to make the child block until parent setup uid/gid mappings nor it
needs to receive the child pid.

1 files changed, 33 insertions, 28 deletions

diff --git a/src/nxt_java.c b/src/nxt_java.c
index 004907d6..c4145c1d 100644
--- a/src/nxt_java.c
+++ b/src/nxt_java.c
@@ -27,9 +27,10 @@
 
 #include "nxt_jars.h"
 
-static nxt_int_t nxt_java_pre_init(nxt_task_t *task,
+static nxt_int_t nxt_java_setup(nxt_task_t *task, nxt_process_t *process,
     nxt_common_app_conf_t *conf);
-static nxt_int_t nxt_java_init(nxt_task_t *task, nxt_common_app_conf_t *conf);
+static nxt_int_t nxt_java_start(nxt_task_t *task,
+    nxt_process_data_t *data);
 static void nxt_java_request_handler(nxt_unit_request_info_t *req);
 static void nxt_java_websocket_handler(nxt_unit_websocket_frame_t *ws);
 static void nxt_java_close_handler(nxt_unit_request_info_t *req);
@@ -49,8 +50,8 @@ NXT_EXPORT nxt_app_module_t  nxt_app_module = {
     compat,
     nxt_string("java"),
     NXT_STRING(NXT_JAVA_VERSION),
-    nxt_java_pre_init,
-    nxt_java_init,
+    nxt_java_setup,
+    nxt_java_start,
 };
 
 typedef struct {
@@ -60,7 +61,8 @@ typedef struct {
 
 
 static nxt_int_t
-nxt_java_pre_init(nxt_task_t *task, nxt_common_app_conf_t *conf)
+nxt_java_setup(nxt_task_t *task, nxt_process_t *process,
+    nxt_common_app_conf_t *conf)
 {
     const char  *unit_jars;
 
@@ -115,24 +117,26 @@ nxt_java_module_jars(const char *jars[], int jar_count)
 
 
 static nxt_int_t
-nxt_java_init(nxt_task_t *task, nxt_common_app_conf_t *conf)
+nxt_java_start(nxt_task_t *task, nxt_process_data_t *data)
 {
-    jint                 rc;
-    char                 *opt, *real_path;
-    char                 **classpath_arr, **unit_jars, **system_jars;
-    JavaVM               *jvm;
-    JNIEnv               *env;
-    jobject              cl, classpath;
-    nxt_str_t            str;
-    nxt_int_t            opt_len, real_path_len;
-    nxt_uint_t           i, unit_jars_count, classpath_count, system_jars_count;
-    JavaVMOption         *jvm_opt;
-    JavaVMInitArgs       jvm_args;
-    nxt_unit_ctx_t       *ctx;
-    nxt_unit_init_t      java_init;
-    nxt_java_data_t      data;
-    nxt_conf_value_t     *value;
-    nxt_java_app_conf_t  *c;
+    jint                   rc;
+    char                   *opt, *real_path;
+    char                   **classpath_arr, **unit_jars, **system_jars;
+    JavaVM                 *jvm;
+    JNIEnv                 *env;
+    jobject                cl, classpath;
+    nxt_str_t              str;
+    nxt_int_t              opt_len, real_path_len;
+    nxt_uint_t             i, unit_jars_count, classpath_count;
+    nxt_uint_t             system_jars_count;
+    JavaVMOption           *jvm_opt;
+    JavaVMInitArgs         jvm_args;
+    nxt_unit_ctx_t         *ctx;
+    nxt_unit_init_t        java_init;
+    nxt_java_data_t        java_data;
+    nxt_conf_value_t       *value;
+    nxt_java_app_conf_t    *c;
+    nxt_common_app_conf_t  *app_conf;
 
     //setenv("ASAN_OPTIONS", "handle_segv=0", 1);
 
@@ -140,7 +144,8 @@ nxt_java_init(nxt_task_t *task, nxt_common_app_conf_t *conf)
     jvm_args.nOptions = 0;
     jvm_args.ignoreUnrecognized = 0;
 
-    c = &conf->u.java;
+    app_conf = data->app;
+    c = &app_conf->u.java;
 
     if (c->options != NULL) {
         jvm_args.nOptions += nxt_conf_array_elements_count(c->options);
@@ -338,8 +343,8 @@ nxt_java_init(nxt_task_t *task, nxt_common_app_conf_t *conf)
         goto env_failed;
     }
 
-    data.env = env;
-    data.ctx = nxt_java_startContext(env, c->webapp, classpath);
+    java_data.env = env;
+    java_data.ctx = nxt_java_startContext(env, c->webapp, classpath);
 
     if ((*env)->ExceptionCheck(env)) {
         nxt_alert(task, "Unhandled exception in application start");
@@ -353,8 +358,8 @@ nxt_java_init(nxt_task_t *task, nxt_common_app_conf_t *conf)
     java_init.callbacks.websocket_handler = nxt_java_websocket_handler;
     java_init.callbacks.close_handler = nxt_java_close_handler;
     java_init.request_data_size = sizeof(nxt_java_request_data_t);
-    java_init.data = &data;
-    java_init.shm_limit = conf->shm_limit;
+    java_init.data = &java_data;
+    java_init.shm_limit = app_conf->shm_limit;
 
     ctx = nxt_unit_init(&java_init);
     if (nxt_slow_path(ctx == NULL)) {
@@ -367,7 +372,7 @@ nxt_java_init(nxt_task_t *task, nxt_common_app_conf_t *conf)
         /* TODO report error */
     }
 
-    nxt_java_stopContext(env, data.ctx);
+    nxt_java_stopContext(env, java_data.ctx);
 
     if ((*env)->ExceptionCheck(env)) {
         (*env)->ExceptionDescribe(env);