Revert "ok, exit() child processes instead of _exit()"

This reverts commit 9ac801c12c48b67b48e5a8ef2876a093b7de73fc.

Reason for revert: breaks threaded mode.

Original change's description:
> ok, exit() child processes instead of _exit()
> 
> We want the atexit() hook to print deferred logs (crash dumps, etc.) only when the main, parent process exits.  Ending the child processes with _exit() instead of exit() avoids calling atexit() hooks, but also global destructors.  This is more complex than we need: we can just print before main() exits.  Only the main, parent process gets there.
> 
> This now runs each child process' global destructors, which makes trace.json "work": we get a trace of whichever child process finishes last.  It's a start.
> 
> Change-Id: I0cc2b12592f0f79e73a43a160b9fd06dba1fee25
> Reviewed-on: https://skia-review.googlesource.com/26800
> Commit-Queue: Mike Klein <mtklein@chromium.org>
> Reviewed-by: Brian Osman <brianosman@google.com>

TBR=mtklein@chromium.org,brianosman@google.com

Change-Id: I695dddaab3b5a51e4698bb7222fc723b544a1d64
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/26943
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>

1 files changed, 8 insertions, 11 deletions

diff --git a/tools/ok.cpp b/tools/ok.cpp
index 8d24b4ddcb..edda9bede0 100644
--- a/tools/ok.cpp
+++ b/tools/ok.cpp
@@ -69,14 +69,13 @@ static thread_local const char* tls_currently_running = "";
 
     static void defer_logging() {
         log_fd = fileno(tmpfile());
-    }
-
-    static void print_deferred_logs() {
-        lseek(log_fd, 0, SEEK_SET);
-        char buf[1024];
-        while (size_t bytes = read(log_fd, buf, sizeof(buf))) {
-            write(2/*stderr*/, buf, bytes);
-        }
+        atexit([] {
+            lseek(log_fd, 0, SEEK_SET);
+            char buf[1024];
+            while (size_t bytes = read(log_fd, buf, sizeof(buf))) {
+                write(2, buf, bytes);
+            }
+        });
     }
 
     void ok_log(const char* msg) {
@@ -92,7 +91,6 @@ static thread_local const char* tls_currently_running = "";
 #else
     static void setup_crash_handler() {}
     static void defer_logging() {}
-    static void print_deferred_logs() {}
 
     void ok_log(const char* msg) {
         fprintf(stderr, "%s\n", msg);
@@ -155,7 +153,7 @@ struct ThreadEngine : Engine {
     struct ForkEngine : Engine {
         bool spawn(std::function<Status(void)> fn) override {
             switch (fork()) {
-                case  0: exit((int)fn());
+                case  0: _exit((int)fn());
                 case -1: return false;
                 default: return true;
             }
@@ -334,7 +332,6 @@ int main(int argc, char** argv) {
         update_stats(s);
     }
     printf("\n");
-    print_deferred_logs();
     return (failed || crashed) ? 1 : 0;
 }