[src/trunk]: src/sbin/ping6 avoid signal handler race. help from deraadt

[itojun <itojun%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/184fdafd4dd2
branches:  trunk
changeset: 502151:184fdafd4dd2
user:      itojun <itojun%NetBSD.org@localhost>
date:      Fri Jan 12 19:13:41 2001 +0000

description:
avoid signal handler race.  help from deraadt

diffstat:

 sbin/ping6/ping6.c |  119 +++++++++++++++++++++++++++++++++++++++-------------
 1 files changed, 88 insertions(+), 31 deletions(-)

diffs (221 lines):

diff -r 238afa4d242d -r 184fdafd4dd2 sbin/ping6/ping6.c
--- a/sbin/ping6/ping6.c        Fri Jan 12 19:03:24 2001 +0000
+++ b/sbin/ping6/ping6.c        Fri Jan 12 19:13:41 2001 +0000
@@ -1,5 +1,5 @@
-/*     $NetBSD: ping6.c,v 1.29 2001/01/12 18:50:58 itojun Exp $        */
-/*     $KAME: ping6.c,v 1.109 2000/12/27 11:32:37 itojun Exp $ */
+/*     $NetBSD: ping6.c,v 1.30 2001/01/12 19:13:41 itojun Exp $        */
+/*     $KAME: ping6.c,v 1.112 2001/01/12 19:11:49 itojun Exp $ */
 
 /*
  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
@@ -81,7 +81,7 @@
 #else
 #include <sys/cdefs.h>
 #ifndef lint
-__RCSID("$NetBSD: ping6.c,v 1.29 2001/01/12 18:50:58 itojun Exp $");
+__RCSID("$NetBSD: ping6.c,v 1.30 2001/01/12 19:13:41 itojun Exp $");
 #endif
 #endif
 
@@ -248,11 +248,17 @@
 struct iovec smsgiov;
 char *scmsg = 0;
 
+volatile int signo;
+volatile int seenalrm;
+volatile int seenint;
+volatile int seeninfo;
+
 int     main __P((int, char *[]));
 void    fill __P((char *, char *));
 int     get_hoplim __P((struct msghdr *));
 struct in6_pktinfo *get_rcvpktinfo __P((struct msghdr *));
-void    onalrm __P((int));
+void    onsignal __P((int));
+void    retransmit __P((void));
 void    oninfo __P((int));
 void    onint __P((int));
 void    pinger __P((void));
@@ -284,7 +290,7 @@
 {
        struct itimerval itimer;
        struct sockaddr_in6 from;
-       struct timeval timeout;
+       struct timeval timeout, *tv;
        struct addrinfo hints;
        fd_set *fdmaskp;
        int fdmasks;
@@ -300,9 +306,6 @@
 #ifdef USE_RFC2292BIS
        struct ip6_rthdr *rthdr = NULL;
 #endif
-#ifndef __OpenBSD__
-       struct timeval tv;
-#endif
 #ifdef IPSEC_POLICY_IPSEC
        char *policy_in = NULL;
        char *policy_out = NULL;
@@ -633,8 +636,8 @@
 
        ident = getpid() & 0xFFFF;
 #ifndef __OpenBSD__
-       gettimeofday(&tv, NULL);
-       srand((unsigned int)(tv.tv_sec ^ tv.tv_usec ^ (long)ident));
+       gettimeofday(&timeout, NULL);
+       srand((unsigned int)(timeout.tv_sec ^ timeout.tv_usec ^ (long)ident));
        memset(nonce, 0, sizeof(nonce));
        for (i = 0; i < sizeof(nonce); i += sizeof(int))
                *((int *)&nonce[i]) = rand();
@@ -963,23 +966,25 @@
        while (preload--)               /* Fire off them quickies. */
                pinger();
 
-       (void)signal(SIGINT, onint);
+       (void)signal(SIGINT, onsignal);
 #ifdef SIGINFO
-       (void)signal(SIGINFO, oninfo);
+       (void)signal(SIGINFO, onsignal);
 #endif
 
        if ((options & F_FLOOD) == 0) {
-               (void)signal(SIGALRM, onalrm);
+               (void)signal(SIGALRM, onsignal);
                itimer.it_interval = interval;
-               itimer.it_value.tv_sec = 0;
-               itimer.it_value.tv_usec = 1;
+               itimer.it_value = interval;
                (void)setitimer(ITIMER_REAL, &itimer, NULL);
+               retransmit();
        }
 
        fdmasks = howmany(s + 1, NFDBITS) * sizeof(fd_mask);
        if ((fdmaskp = malloc(fdmasks)) == NULL)
                err(1, "malloc");
 
+       signo = seenalrm = seenint = seeninfo = 0;
+
        for (;;) {
                struct msghdr m;
                struct cmsghdr *cm;
@@ -990,11 +995,30 @@
                        pinger();
                        timeout.tv_sec = 0;
                        timeout.tv_usec = 10000;
-                       memset(fdmaskp, 0, fdmasks);
-                       FD_SET(s, fdmaskp);
-                       if (select(s + 1, fdmaskp, NULL, NULL, &timeout) < 1)
-                               continue;
-               }
+                       tv = &timeout;
+               } else
+                       tv = NULL;
+               memset(fdmaskp, 0, fdmasks);
+               FD_SET(s, fdmaskp);
+               cc = select(s + 1, fdmaskp, NULL, NULL, tv);
+               if ((cc < 0 && errno == EINTR) || ((options & F_FLOOD) && signo)) {
+                       if (seenalrm) {
+                               retransmit();
+                               seenalrm = 0;
+                       }
+                       if (seenint) {
+                               onint(SIGINT);
+                               seenint = 0;
+                       }
+                       if (seeninfo) {
+                               oninfo(SIGINFO);
+                               seeninfo = 0;
+                       }
+                       signo = 0;
+                       continue;
+               } else if (cc == 0)
+                       continue;
+
                fromlen = sizeof(from);
 
                m.msg_name = (caddr_t)&from;
@@ -1008,14 +1032,33 @@
                m.msg_control = (caddr_t)buf;
                m.msg_controllen = sizeof(buf);
 
-               if ((cc = recvmsg(s, &m, 0)) < 0) {
-                       if (errno == EINTR)
+               cc = recvmsg(s, &m, 0);
+               if (cc < 0) {
+                       if (errno != EINTR) {
+                               warn("recvmsg");
+                               continue;
+                       }
+                       if (!signo)
                                continue;
-                       warn("recvfrom");
+                       if (seenalrm) {
+                               retransmit();
+                               seenalrm = 0;
+                       }
+                       if (seenint) {
+                               onint(SIGINT);
+                               seenint = 0;
+                       }
+                       if (seeninfo) {
+                               oninfo(SIGINFO);
+                               seeninfo = 0;
+                       }
                        continue;
+               } else {
+                       /*
+                        * an ICMPv6 message (probably an echoreply) arrived.
+                        */
+                       pr_pack(packet, cc, &m);
                }
-
-               pr_pack(packet, cc, &m);
                if (npackets && nreceived >= npackets)
                        break;
        }
@@ -1023,14 +1066,30 @@
        exit(nreceived == 0);
 }
 
+void
+onsignal(sig)
+       int sig;
+{
+       signo = sig;
+       switch (sig) {
+       case SIGALRM:
+               seenalrm++;
+               break;
+       case SIGINT:
+               seenint++;
+               break;
+       case SIGINFO:
+               seeninfo++;
+               break;
+       }
+}
+
 /*
- * onalrm --
+ * retransmit --
  *     This routine transmits another ping6.
  */
-/* ARGSUSED */
 void
-onalrm(signo)
-       int signo;
+retransmit()
 {
        struct itimerval itimer;
 
@@ -1909,10 +1968,8 @@
 oninfo(notused)
        int notused;
 {
-       int save_errno = errno;
 
        summary();
-       errno = save_errno;
 }
 
 /*