Core: add configuration generations to cycles

Store a configuration generation number on each cycle and include it in
Unix process titles. The first runtime cycle starts at generation 1.
Successful reloads increment the generation for new master, worker,
and helper processes.

Refactor Unix setproctitle handling to support formatted titles while
preserving the existing wrapper macro.

Closes: https://github.com/nginx/nginx/issues/1238
Origin: <948b0c7df6>
Signed-off-by: Alex Chen <alexdcdc@gmail.com>

src/core/ngx_cycle.c

@@ -221,6 +221,8 @@ ngx_init_cycle(ngx_cycle_t *old_cycle)
 
     ngx_strlow(cycle->hostname.data, (u_char *) hostname, cycle->hostname.len);
 
+    cycle->generation = old_cycle->generation + 1;
+
 
     if (ngx_cycle_modules(cycle) != NGX_OK) {
         ngx_destroy_pool(pool);

src/core/ngx_cycle.h

@@ -83,6 +83,8 @@ struct ngx_cycle_s {
     ngx_str_t                 error_log;
     ngx_str_t                 lock_file;
     ngx_str_t                 hostname;
+
+    uint64_t                  generation;
 };
 
 

src/os/unix/ngx_process_cycle.c

@@ -11,6 +11,7 @@
 #include <ngx_channel.h>
 
 
+static void ngx_update_process_title(ngx_cycle_t *cycle, ngx_uint_t single);
 static void ngx_start_worker_processes(ngx_cycle_t *cycle, ngx_int_t n,
     ngx_int_t type);
 static void ngx_start_cache_manager_processes(ngx_cycle_t *cycle,
@@ -73,10 +74,6 @@ static ngx_open_file_t  ngx_exit_log_file;
 void
 ngx_master_process_cycle(ngx_cycle_t *cycle)
 {
-    char              *title;
-    u_char            *p;
-    size_t             size;
-    ngx_int_t          i;
     ngx_uint_t         sigio;
     sigset_t           set;
     struct itimerval   itv;
@@ -104,25 +101,7 @@ ngx_master_process_cycle(ngx_cycle_t *cycle)
     sigemptyset(&set);
 
 
-    size = sizeof(master_process);
-
-    for (i = 0; i < ngx_argc; i++) {
-        size += ngx_strlen(ngx_argv[i]) + 1;
-    }
-
-    title = ngx_pnalloc(cycle->pool, size);
-    if (title == NULL) {
-        /* fatal */
-        exit(2);
-    }
-
-    p = ngx_cpymem(title, master_process, sizeof(master_process) - 1);
-    for (i = 0; i < ngx_argc; i++) {
-        *p++ = ' ';
-        p = ngx_cpystrn(p, (u_char *) ngx_argv[i], size);
-    }
-
-    ngx_setproctitle(title);
+    ngx_update_process_title(cycle, 0);
 
 
     ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);
@@ -229,6 +208,7 @@ ngx_master_process_cycle(ngx_cycle_t *cycle)
             }
 
             ngx_cycle = cycle;
+            ngx_update_process_title(cycle, 0);
             ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx,
                                                    ngx_core_module);
             ngx_start_worker_processes(cycle, ccf->worker_processes,
@@ -280,6 +260,8 @@ ngx_single_process_cycle(ngx_cycle_t *cycle)
 {
     ngx_uint_t  i;
 
+    ngx_update_process_title(cycle, 1);
+
     if (ngx_set_environment(cycle, NULL) == NULL) {
         /* fatal */
         exit(2);
@@ -321,6 +303,7 @@ ngx_single_process_cycle(ngx_cycle_t *cycle)
             }
 
             ngx_cycle = cycle;
+            ngx_update_process_title(cycle, 1);
         }
 
         if (ngx_reopen) {
@@ -332,6 +315,32 @@ ngx_single_process_cycle(ngx_cycle_t *cycle)
 }
 
 
+static void
+ngx_update_process_title(ngx_cycle_t *cycle, ngx_uint_t single)
+{
+    u_char     *p, *end, args[2048];
+    ngx_int_t   i;
+
+    end = args + sizeof(args) - 1;
+
+    p = ngx_slprintf(args, end, "%s", ngx_argv[0]);
+
+    for (i = 1; i < ngx_argc; i++) {
+        p = ngx_slprintf(p, end, " %s", ngx_argv[i]);
+    }
+
+    if (p < end) {
+        *p++ = ']';
+    }
+
+    *p = '\0';
+
+    ngx_setproctitle_fmt("%s #%llu [%s",
+                         single ? "single process" : (char *) master_process,
+                         (unsigned long long) cycle->generation, args);
+}
+
+
 static void
 ngx_start_worker_processes(ngx_cycle_t *cycle, ngx_int_t n, ngx_int_t type)
 {
@@ -705,7 +714,7 @@ ngx_worker_process_cycle(ngx_cycle_t *cycle, void *data)
 
     ngx_worker_process_init(cycle, worker);
 
-    ngx_setproctitle("worker process");
+    ngx_setproctitle_gen("worker process", cycle->generation);
 
     for ( ;; ) {
 
@@ -729,7 +738,8 @@ ngx_worker_process_cycle(ngx_cycle_t *cycle, void *data)
             ngx_quit = 0;
             ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0,
                           "gracefully shutting down");
-            ngx_setproctitle("worker process is shutting down");
+            ngx_setproctitle_gen("worker process is shutting down",
+                                 cycle->generation);
 
             if (!ngx_exiting) {
                 ngx_exiting = 1;
@@ -1114,7 +1124,7 @@ ngx_cache_manager_process_cycle(ngx_cycle_t *cycle, void *data)
 
     ngx_use_accept_mutex = 0;
 
-    ngx_setproctitle(ctx->name);
+    ngx_setproctitle_gen(ctx->name, cycle->generation);
 
     ngx_add_timer(&ev, ctx->delay);
 

src/os/unix/ngx_setproctitle.c

@@ -76,9 +76,11 @@ ngx_init_setproctitle(ngx_log_t *log)
 
 
 void
-ngx_setproctitle(char *title)
+ngx_setproctitle_fmt(const char *fmt, ...)
 {
+    int         n;
     u_char     *p;
+    va_list     args;
 
 #if (NGX_SOLARIS)
 
@@ -92,7 +94,15 @@ ngx_setproctitle(char *title)
     p = ngx_cpystrn((u_char *) ngx_os_argv[0], (u_char *) "nginx: ",
                     ngx_os_argv_last - ngx_os_argv[0]);
 
-    p = ngx_cpystrn(p, (u_char *) title, ngx_os_argv_last - (char *) p);
+    va_start(args, fmt);
+    n = vsnprintf((char *) p, ngx_os_argv_last - (char *) p, fmt, args);
+    va_end(args);
+
+    if (n < 0) {
+        n = 0;
+    }
+
+    p += ngx_min((size_t) n, (size_t) (ngx_os_argv_last - (char *) p));
 
 #if (NGX_SOLARIS)
 

src/os/unix/ngx_setproctitle.h

@@ -14,7 +14,7 @@
 /* FreeBSD, NetBSD, OpenBSD */
 
 #define ngx_init_setproctitle(log) NGX_OK
-#define ngx_setproctitle(title)    setproctitle("%s", title)
+#define ngx_setproctitle_fmt       setproctitle
 
 
 #else /* !NGX_HAVE_SETPROCTITLE */
@@ -27,7 +27,7 @@
 #define NGX_SETPROCTITLE_PAD       ' '
 
 ngx_int_t ngx_init_setproctitle(ngx_log_t *log);
-void ngx_setproctitle(char *title);
+void ngx_setproctitle_fmt(const char *fmt, ...);
 
 #elif (NGX_LINUX) || (NGX_DARWIN)
 
@@ -35,12 +35,12 @@ void ngx_setproctitle(char *title);
 #define NGX_SETPROCTITLE_PAD       '\0'
 
 ngx_int_t ngx_init_setproctitle(ngx_log_t *log);
-void ngx_setproctitle(char *title);
+void ngx_setproctitle_fmt(const char *fmt, ...);
 
 #else
 
 #define ngx_init_setproctitle(log) NGX_OK
-#define ngx_setproctitle(title)
+static ngx_inline void ngx_setproctitle_fmt(const char *fmt, ...) { /* void */ }
 
 #endif /* OSes */
 
@@ -49,4 +49,10 @@ void ngx_setproctitle(char *title);
 #endif /* NGX_HAVE_SETPROCTITLE */
 
 
+#define ngx_setproctitle(title)           ngx_setproctitle_fmt("%s", title)
+
+#define ngx_setproctitle_gen(title, gen)                                      \
+    ngx_setproctitle_fmt("%s #%llu", title, (unsigned long long) gen)
+
+
 #endif /* _NGX_SETPROCTITLE_H_INCLUDED_ */