e015d0659
Denys Vlasenko
2018-02-11
Subject
arping: fix the case when inherited signal mask masks out ALRM
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networking/arping.c+16 -7
| @@ -413,28 +413,37 @@ int arping_main(int argc UNUSED_PARAM, char **argv) | |
| printf(" from %s %s\n", inet_ntoa(src), device); | |
| } | |
| + | packet = xmalloc(4096); |
| + | |
| signal_SA_RESTART_empty_mask(SIGINT, (void (*)(int))finish); | |
| signal_SA_RESTART_empty_mask(SIGALRM, (void (*)(int))catcher); | |
| + | /* Send the first packet, arm ALRM */ |
| catcher(); | |
| - | packet = xmalloc(4096); |
| while (1) { | |
| - | sigset_t sset, osset; |
| + | sigset_t sset; |
| struct sockaddr_ll from; | |
| socklen_t alen = sizeof(from); | |
| int cc; | |
| + | sigemptyset(&sset); |
| + | sigaddset(&sset, SIGALRM); |
| + | sigaddset(&sset, SIGINT); |
| + | /* Unblock SIGALRM so that the previously called alarm() |
| + | * can prevent recvfrom from blocking forever in case the |
| + | * inherited procmask is blocking SIGALRM. |
| + | */ |
| + | sigprocmask(SIG_UNBLOCK, &sset, NULL); |
| + | |
| cc = recvfrom(sock_fd, packet, 4096, 0, (struct sockaddr *) &from, &alen); | |
| + | |
| + | /* Don't allow SIGALRMs while we process the reply */ |
| + | sigprocmask(SIG_BLOCK, &sset, NULL); |
| if (cc < 0) { | |
| bb_perror_msg("recvfrom"); | |
| continue; | |
| } | |
| - | sigemptyset(&sset); |
| - | sigaddset(&sset, SIGALRM); |
| - | sigaddset(&sset, SIGINT); |
| - | sigprocmask(SIG_BLOCK, &sset, &osset); |
| recv_pack(packet, cc, &from); | |
| - | sigprocmask(SIG_SETMASK, &osset, NULL); |
| } | |
| } | |