Commit 1aef4dd8 authored by Jim Jagielski's avatar Jim Jagielski
Browse files

Merge r1618555 from trunk: 

prefork: Ignore SIGINT in child. This fixes race-condition in signals handling
when httpd is runnning on foreground and user hits ctrl+c. In this case, SIGINT
is sent to all children followed by SIGTERM from the main process, which
interrupts the SIGINT handler and leads to inconsistency (process freezes
or crashes).

Submitted by: jkaluza
Reviewed by: ylavic, jorton, jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1805222 13f79535-47bb-0310-9956-ffa450edef68
parent 6a466488

STATUS

+0 −11
Original line number Diff line number Diff line
@@ -116,17 +116,6 @@ RELEASE SHOWSTOPPERS: 
PATCHES ACCEPTED TO BACKPORT FROM TRUNK:

  [ start all new proposals below, under PATCHES PROPOSED. ]



   *) prefork: This fixes race-condition in signals handling when httpd is

               runnning on foreground and user hits ctrl+c

     trunk patch: http://svn.apache.org/r1618555

     2.4.x patch: svn merge -c 1618555 ^/httpd/httpd/trunk .

     +1: ylavic, jorton, jim

     jailetc36: untested because I'm unsure on how to reproduce the race, but

                the patch description looks straighforward.

                If confirmed, it would worth, IMHO, a CHANGE entry and maybe a

                2.2.x backport.

                [jorton: race, so hard to repro, triggered regularly w/docker.]



  *) core: ap_server_config_defines and ap_server_{pre,post}_read_config

           constantness and bytes saving, no functional change.

     trunk patch: http://svn.apache.org/r1713043

server/mpm/prefork/prefork.c

+10 −0
Original line number Diff line number Diff line
@@ -220,6 +220,9 @@ static void clean_child_exit(int code) 
{

    retained->mpm->mpm_state = AP_MPMQ_STOPPING;



    apr_signal(SIGHUP, SIG_IGN);

    apr_signal(SIGTERM, SIG_IGN);



    if (pchild) {

        apr_pool_destroy(pchild);

    }
@@ -699,6 +702,13 @@ static int make_child(server_rec *s, int slot, int bucket) 
         */

        apr_signal(SIGHUP, just_die);

        apr_signal(SIGTERM, just_die);

        /* Ignore SIGINT in child. This fixes race-condition in signals

         * handling when httpd is runnning on foreground and user hits ctrl+c.

         * In this case, SIGINT is sent to all children followed by SIGTERM

         * from the main process, which interrupts the SIGINT handler and

         * leads to inconsistency.

         */

        apr_signal(SIGINT, SIG_IGN);

        /* The child process just closes listeners on AP_SIG_GRACEFUL.

         * The pod is used for signalling the graceful restart.

         */