Module Name: src
Committed By: dholland
Date: Thu Nov 24 00:05:13 UTC 2016
Modified Files:
src/usr.bin/netstat: if.c
Log Message:
Fix "sidewaysintpr", the thing that prints interface statistics in a
loop, to use signals properly. There are two copies of this code; one
uses kvm and the other uses sysctls. One copy had been updated to use
sigset_t and sigsuspend; the other was using vintage sigpause(). Sync
up the code so both use sigpause. Also, use sig_atomic_t, and block
SIGALRM when not waiting for it to avoid a small and unlikely but real
race.
Since the non-modernized copy of the code *had* for some been
modernized to use setitimer instead of just alarm(), propagate that
change to the other copy.
These copies could share more logic than they do.
To generate a diff of this commit:
cvs rdiff -u -r1.89 -r1.90 src/usr.bin/netstat/if.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/usr.bin/netstat/if.c
diff -u src/usr.bin/netstat/if.c:1.89 src/usr.bin/netstat/if.c:1.90
--- src/usr.bin/netstat/if.c:1.89 Thu Jul 14 20:38:20 2016
+++ src/usr.bin/netstat/if.c Thu Nov 24 00:05:13 2016
@@ -1,4 +1,4 @@
-/* $NetBSD: if.c,v 1.89 2016/07/14 20:38:20 christos Exp $ */
+/* $NetBSD: if.c,v 1.90 2016/11/24 00:05:13 dholland Exp $ */
/*
* Copyright (c) 1983, 1988, 1993
@@ -34,7 +34,7 @@
#if 0
static char sccsid[] = "from: @(#)if.c 8.2 (Berkeley) 2/21/94";
#else
-__RCSID("$NetBSD: if.c,v 1.89 2016/07/14 20:38:20 christos Exp $");
+__RCSID("$NetBSD: if.c,v 1.90 2016/11/24 00:05:13 dholland Exp $");
#endif
#endif /* not lint */
@@ -100,7 +100,7 @@ static void intpr_sysctl(void);
static void intpr_kvm(u_long, void (*)(const char *));
struct iftot iftot[MAXIF], ip_cur, ip_old, sum_cur, sum_old;
-bool signalled; /* set if alarm goes off "early" */
+static sig_atomic_t signalled; /* set when alarm goes off */
static unsigned redraw_lines = 21;
@@ -712,7 +712,9 @@ iftot_print_sum(struct iftot *cur, struc
__dead static void
sidewaysintpr_sysctl(unsigned interval)
{
+ struct itimerval it;
sigset_t emptyset;
+ sigset_t noalrm;
unsigned line;
set_lines();
@@ -724,9 +726,18 @@ sidewaysintpr_sysctl(unsigned interval)
exit(1);
}
- (void)signal(SIGALRM, catchalarm);
+ sigemptyset(&emptyset);
+ sigemptyset(&noalrm);
+ sigaddset(&noalrm, SIGALRM);
+ sigprocmask(SIG_SETMASK, &noalrm, NULL);
+
signalled = 0;
- (void)alarm(interval);
+ (void)signal(SIGALRM, catchalarm);
+
+ it.it_interval.tv_sec = it.it_value.tv_sec = interval;
+ it.it_interval.tv_usec = it.it_value.tv_usec = 0;
+ setitimer(ITIMER_REAL, &it, NULL);
+
banner:
iftot_banner(&ip_cur);
@@ -749,11 +760,10 @@ loop:
putchar('\n');
fflush(stdout);
line++;
- sigemptyset(&emptyset);
- if (!signalled)
+ if (signalled == 0) {
sigsuspend(&emptyset);
+ }
signalled = 0;
- (void)alarm(interval);
if (line == redraw_lines)
goto banner;
goto loop;
@@ -764,13 +774,14 @@ static void
sidewaysintpr_kvm(unsigned interval, u_long off)
{
struct itimerval it;
+ sigset_t emptyset;
+ sigset_t noalrm;
struct ifnet ifnet;
u_long firstifnet;
struct iftot *ip, *total;
unsigned line;
struct iftot *lastif, *sum, *interesting;
struct ifnet_head ifhead; /* TAILQ_HEAD */
- int oldmask;
set_lines();
@@ -806,8 +817,13 @@ sidewaysintpr_kvm(unsigned interval, u_l
}
lastif = ip;
+ sigemptyset(&emptyset);
+ sigemptyset(&noalrm);
+ sigaddset(&noalrm, SIGALRM);
+ sigprocmask(SIG_SETMASK, &noalrm, NULL);
+
+ signalled = 0;
(void)signal(SIGALRM, catchalarm);
- signalled = false;
it.it_interval.tv_sec = it.it_value.tv_sec = interval;
it.it_interval.tv_usec = it.it_value.tv_usec = 0;
@@ -980,12 +996,10 @@ loop:
putchar('\n');
fflush(stdout);
line++;
- oldmask = sigblock(sigmask(SIGALRM));
- if (! signalled) {
- sigpause(0);
+ if (signalled == 0) {
+ sigsuspend(&emptyset);
}
- sigsetmask(oldmask);
- signalled = false;
+ signalled = 0;
if (line == redraw_lines)
goto banner;
goto loop;
