[PATCH 3 of 3] chg: forward SIGINT, SIGHUP to process group

[Jun Wu]

Excerpts from Jun Wu's message of 2016-07-17 23:09:43 +0100:
> -static void setupsignalhandler(pid_t pid)
> +static void setupsignalhandler(const hgclient_t *hgc)
>  {
> -    if (pid <= 0)
> +    peerpgid = hgc_peerpgid(hgc);
> +    peerpid = hgc_peerpid(hgc);

I noticed this changed behavior a bit as I pursued short code: the second
setupsignalhandler call (if exists) becomes unsafe and the if condition is
not quite right. It's probably better not to save lines:

diff --git a/contrib/chg/chg.c b/contrib/chg/chg.c
--- a/contrib/chg/chg.c
+++ b/contrib/chg/chg.c
@@ -404,10 +404,14 @@ static void handlechildsignal(int sig UN
 
 static void setupsignalhandler(const hgclient_t *hgc)
 {
-       peerpgid = hgc_peerpgid(hgc);
-       peerpid = hgc_peerpid(hgc);
-       if (peerpgid <= 0 && peerpid <= 0)
+       pid_t pid = hgc_peerpid(hgc);
+       if (pid <= 0)
                return;
+       pid_t pgid = hgc_peerpgid(hgc);
+       if (pgid < 0)
+               pgid = 0;
+       peerpid = pid;
+       peerpgid = pgid;
 
        struct sigaction sa;
        memset(&sa, 0, sizeof(sa));