[pgpool-committers: 3334] pgpool: Fix usage of wait(2) in pgpool main process

[Tatsuo Ishii]

Fix usage of wait(2) in pgpool main process

Per [pgpool-hackers: 1444]. Here is the copy of the message:

Hi Usama,

I have noticed that the usage of wait(2) in pgpool main could cause
infinite wait in the system call.

    /* wait for all children to exit */
    do
    {
        wpid = wait(NULL);
    }while (wpid > 0 || (wpid == -1 && errno == EINTR));

When child process dies, SIGCHLD signal is raised and wait(2) knows
the event. However, multiple child death does not necessarily creates
exact same number of SIGCHLD signal as the number of dead children and
wait(2) could wait for an event which never happens in this case. I
actually encountered this situation while testing pgpool-II. Solution
is, to use waitpid(2) instead of wait(2).

Branch
------
V3_1_STABLE

Details
-------
http://git.postgresql.org/gitweb?p=pgpool2.git;a=commitdiff;h=085230b5c4fb6bbe963f16d28ba88bceb9687d65

Modified Files
--------------
main.c | 28 +++++++++++++++++++++-------
1 file changed, 21 insertions(+), 7 deletions(-)