new file mode 100644
--- /dev/null
+++ b/src/os/unix/ngx_process.c
@@ -0,0 +1,112 @@
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+
+
+void testone(ngx_log_t *log)
+{
+    ngx_log_debug(log, "child process");
+    ngx_msleep(5000);
+    exit(0);
+}
+
+
+int ngx_spawn_process(ngx_log_t *log)
+{
+    pid_t     pid;
+    sigset_t  set, oset; 
+
+    sigemptyset(&set);
+    sigaddset(&set, SIGCHLD);
+    if (sigprocmask(SIG_BLOCK, &set, &oset) == -1) {
+        ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, "sigprocmask() failed");
+    }
+
+    pid = fork();
+
+    if (pid == -1 || pid == 0) {
+        if (sigprocmask(SIG_SETMASK, &oset, &set) == -1) {
+            ngx_log_error(NGX_LOG_ALERT, log, ngx_errno,
+                          "sigprocmask() failed");
+        }
+    }
+
+    switch (pid) {
+    case -1:
+        ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, "fork() failed");
+        return NGX_ERROR;
+
+    case 0:
+        testone(log);
+        break;
+
+    default:
+    }
+
+ngx_log_debug(log, "parent process, child: " PID_FMT _ pid);
+
+    /* book keeping */
+
+    if (sigprocmask(SIG_SETMASK, &oset, &set) == -1) {
+        ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, "sigprocmask() failed");
+    }
+
+    return NGX_OK;
+}
+
+
+void ngx_sigchld_handler(int signo)
+{
+    int             status, one;
+    pid_t           pid;
+    ngx_err_t       err;
+    struct timeval  tv;
+
+    ngx_gettimeofday(&tv);
+
+    if (ngx_cached_time != tv.tv_sec) {
+        ngx_cached_time = tv.tv_sec;
+        ngx_time_update();
+    }
+
+    one = 0;
+
+    for ( ;; ) {
+        pid = waitpid(-1, &status, WNOHANG);
+
+        if (pid == 0) {
+            return;
+        }
+
+        if (pid == -1) {
+            err = ngx_errno;
+
+            if (err == NGX_EINTR) {
+                continue;
+            }
+
+            if (err == NGX_ECHILD && one) {
+                return;
+            }
+
+            ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, errno,
+                          "waitpid() failed");
+            return;
+        }
+
+        one = 1;
+
+        ngx_log_error(NGX_LOG_INFO, ngx_cycle->log, 0,
+                      "process " PID_FMT " exited with code %d", pid, status);
+
+        /* TODO: restart handler */
+
+#if 0
+        ngx_msleep(2000);
+#endif
+
+#if 0
+        ngx_spawn_process(ngx_cycle->log);
+#endif
+    }
+}