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[PATCH 1/2] Cygwin: fork: Always pause child after fixups.
- From: Michael Haubenwallner <michael dot haubenwallner at ssi-schaefer dot com>
- To: cygwin-patches at cygwin dot com
- Cc: Michael Haubenwallner <michael dot haubenwallner at ssi-schaefer dot com>
- Date: Tue, 30 Apr 2019 09:09:13 +0200
- Subject: [PATCH 1/2] Cygwin: fork: Always pause child after fixups.
- References: <20190412175825.GD4248@calimero.vinschen.de>
Pause the child process after performing fork fixups even if there were
no dynamically loaded dlls with extra data/bss transfers to wait for.
This allows the parent process to cancel the current fork call even if
the child process was successfully initialized already.
This is a preparation for when the parent does remember the child no
earlier than after successful child initialization.
winsup/cygwin/fork.cc | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
diff --git a/winsup/cygwin/fork.cc b/winsup/cygwin/fork.cc
index 7e1c08990..59b13806c 100644
@@ -180,13 +180,10 @@ frok::child (volatile char * volatile here)
- /* If we haven't dynamically loaded any dlls, just signal the parent.
- Otherwise, tell the parent that we've loaded all the dlls
- and wait for the parent to fill in the loaded dlls' data/bss. */
- if (!load_dlls)
- sync_with_parent ("performed fork fixup", false);
- sync_with_parent ("loaded dlls", true);
+ /* Signal that we have successfully initialized, so the parent can
+ - transfer data/bss for dynamically loaded dlls (if any), or
+ - terminate the current fork call even if the child is initialized. */
+ sync_with_parent ("performed fork fixups and dynamic dll loading", true);
init_console_handler (myself->ctty > 0);
ForceCloseHandle1 (fork_info->forker_finished, forker_finished);
@@ -477,7 +474,8 @@ frok::parent (volatile char * volatile stack_here)
- /* Start thread, and then wait for it to reload dlls. */
+ /* Start the child up, and then wait for it to
+ perform fork fixups and dynamic dll loading (if any). */
if (!ch.sync (child->pid, hchild, FORK_WAIT_TIMEOUT))
@@ -508,10 +506,11 @@ frok::parent (volatile char * volatile stack_here)
- /* Start the child up again. */
- resume_child (forker_finished);
+ /* Finally start the child up. */
+ resume_child (forker_finished);
forker_finished = NULL;