[PATCH 01/10] box: zap atfork callback

[Vladimir Davydov <vdavydov.dev@gmail.com>]

box_atfork calls wal_atfork which in turn calls xlog_atfork for the wal
and vylog files. A comment to xlog_atfork says that it's necessary to
prevent atexit handlers in a child from closing xlog files again, but we
don't use atexit for that anymore. A comment to box_atfork says that
box.coredump forks to write a core, but there's no box.coredump anymore.
There's also a comment mentioning box.cfg.background, but when we fork
that early there's no xlog file open.

To sum it up, atfork looks like a piece of legacy code. Let's get rid of
it now so as not to bother patching it later.
---
 src/box/box.cc | 10 ----------
 src/box/box.h  |  6 ------
 src/box/wal.c  | 16 ----------------
 src/box/wal.h  |  3 ---
 src/box/xlog.c | 16 ----------------
 src/box/xlog.h |  7 -------
 src/main.cc    |  1 -
 7 files changed, 59 deletions(-)

diff --git a/src/box/box.cc b/src/box/box.cc
index 7828f575..bb8aca36 100644
--- a/src/box/box.cc
+++ b/src/box/box.cc
@@ -2167,16 +2167,6 @@ box_cfg(void)
 	}
 }
 
-/**
- * box.coredump() forks to save a core. The entire
- * server forks in box.cfg{} if background=true.
- */
-void
-box_atfork()
-{
-	wal_atfork();
-}
-
 int
 box_checkpoint()
 {
diff --git a/src/box/box.h b/src/box/box.h
index 53d88ab7..53b5eb45 100644
--- a/src/box/box.h
+++ b/src/box/box.h
@@ -93,12 +93,6 @@ box_cfg(void);
 bool
 box_is_configured(void);
 
-/**
- * A pthread_atfork() callback for box
- */
-void
-box_atfork(void);
-
 void
 box_set_ro(bool ro);
 
diff --git a/src/box/wal.c b/src/box/wal.c
index 0ea15a43..25bceb68 100644
--- a/src/box/wal.c
+++ b/src/box/wal.c
@@ -1383,19 +1383,3 @@ wal_notify_watchers(struct wal_writer *writer, unsigned events)
 	rlist_foreach_entry(watcher, &writer->watchers, next)
 		wal_watcher_notify(watcher, events);
 }
-
-
-/**
- * After fork, the WAL writer thread disappears.
- * Make sure that atexit() handlers in the child do
- * not try to stop a non-existent thread or write
- * a second EOF marker to an open file.
- */
-void
-wal_atfork()
-{
-	if (xlog_is_open(&wal_writer_singleton.current_wal))
-		xlog_atfork(&wal_writer_singleton.current_wal);
-	if (xlog_is_open(&vy_log_writer.xlog))
-		xlog_atfork(&vy_log_writer.xlog);
-}
diff --git a/src/box/wal.h b/src/box/wal.h
index 4e500d2a..a88a3f23 100644
--- a/src/box/wal.h
+++ b/src/box/wal.h
@@ -164,9 +164,6 @@ void
 wal_clear_watcher(struct wal_watcher *watcher,
 		  void (*process_cb)(struct cbus_endpoint *));
 
-void
-wal_atfork();
-
 enum wal_mode
 wal_mode();
 
diff --git a/src/box/xlog.c b/src/box/xlog.c
index 8254cce2..82588682 100644
--- a/src/box/xlog.c
+++ b/src/box/xlog.c
@@ -1472,22 +1472,6 @@ xlog_close(struct xlog *l, bool reuse_fd)
 	return rc;
 }
 
-/**
- * Free xlog memory and destroy it cleanly, without side
- * effects (for use in the atfork handler).
- */
-void
-xlog_atfork(struct xlog *xlog)
-{
-	/*
-	 * Close the file descriptor STDIO buffer does not
-	 * make its way into the respective file in
-	 * fclose().
-	 */
-	close(xlog->fd);
-	xlog->fd = -1;
-}
-
 /* }}} */
 
 /* {{{ struct xlog_cursor */
diff --git a/src/box/xlog.h b/src/box/xlog.h
index a48b05fc..964d303e 100644
--- a/src/box/xlog.h
+++ b/src/box/xlog.h
@@ -550,13 +550,6 @@ xlog_sync(struct xlog *l);
 int
 xlog_close(struct xlog *l, bool reuse_fd);
 
-/**
- * atfork() handler function to close the log pointed
- * at by xlog in the child.
- */
-void
-xlog_atfork(struct xlog *xlog);
-
 /* {{{ xlog_tx_cursor - iterate over rows in xlog transaction */
 
 /**
diff --git a/src/main.cc b/src/main.cc
index 606c64c1..68c67773 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -341,7 +341,6 @@ static void
 tarantool_atfork()
 {
 	signal_reset();
-	box_atfork();
 }
 
 /**
-- 
2.11.0