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Use a socketpair rather than a pair of pipes for communication between

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ndhc and ifch, similar to sockd.  A single pipe is also maintained so
that SIGPIPE can bound the lifetime of an orphaned ifch process.
This commit is contained in:
Nicholas J. Kain
2014-04-07 03:44:02 -04:00
parent e2ee728982
commit 5fa2030bab
4 changed files with 22 additions and 43 deletions
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49
src/ndhc.c
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@@ -241,7 +241,7 @@ static void fail_if_state_dir_dne(void)
static void handle_ifch_message(void)
{
char c;
ssize_t r = safe_read(pToNdhcR, &c, sizeof c);
ssize_t r = safe_recv(ifchSock[0], &c, sizeof c, MSG_DONTWAIT);
if (r == 0) {
// Remote end hung up.
exit(EXIT_SUCCESS);
@@ -273,7 +273,7 @@ static void do_ndhc_work(void)
setup_signals_ndhc();
epoll_add(cs.epollFd, cs.nlFd);
epoll_add(cs.epollFd, pToNdhcR);
epoll_add(cs.epollFd, ifchSock[0]);
set_listen_raw(&cs);
nowts = curms();
goto jumpstart;
@@ -296,7 +296,7 @@ static void do_ndhc_work(void)
handle_arp_response(&cs);
else if (fd == cs.nlFd)
handle_nl_message(&cs);
else if (fd == pToNdhcR)
else if (fd == ifchSock[0])
handle_ifch_message();
else
suicide("epoll_wait: unknown fd");
@@ -336,39 +336,20 @@ char resolv_conf_d[PATH_MAX] = "";
static char pidfile[PATH_MAX] = PID_FILE_DEFAULT;
static uid_t ndhc_uid = 0;
static gid_t ndhc_gid = 0;
int pToNdhcR;
int pToNdhcW;
int pToIfchR;
int pToIfchW;
int ifchSock[2];
int ifchPipe[2];
int sockdSock[2];
int sockdPipe[2];
static void create_ifch_ipc_pipes(void) {
int niPipe[2];
int inPipe[2];
if (pipe2(niPipe, 0))
suicide("FATAL - can't create ndhc -> ndhc-ifch pipe: %s",
strerror(errno));
if (fcntl(niPipe[0], F_SETFL, fcntl(niPipe[0], F_GETFL) | O_NONBLOCK) < 0)
suicide("FATAL - failed to set ndhc -> ndhc-ifch read-side nonblocking: %s",
strerror(errno));
pToNdhcR = niPipe[0];
pToNdhcW = niPipe[1];
if (pipe2(inPipe, 0))
suicide("FATAL - can't create ndhc-ifch -> ndhc pipe: %s",
strerror(errno));
if (fcntl(inPipe[0], F_SETFL, fcntl(inPipe[0], F_GETFL) | O_NONBLOCK) < 0)
suicide("FATAL - failed to set ndhc-ifch -> ndhc read-side nonblocking: %s",
strerror(errno));
pToIfchR = inPipe[0];
pToIfchW = inPipe[1];
if (pipe(ifchPipe))
suicide("FATAL - can't create ndhc/ifch pipe: %s", strerror(errno));
if (socketpair(AF_UNIX, SOCK_DGRAM, 0, ifchSock) < 0)
suicide("FATAL - can't create ndhc/ifch socket: %s", strerror(errno));
}
static void create_sockd_ipc_pipes(void) {
if (pipe2(sockdPipe, 0))
if (pipe(sockdPipe))
suicide("FATAL - can't create ndhc/sockd pipe: %s", strerror(errno));
if (socketpair(AF_UNIX, SOCK_DGRAM, 0, sockdSock) < 0)
suicide("FATAL - can't create ndhc/sockd socket: %s", strerror(errno));
@@ -379,14 +360,14 @@ static void spawn_ifch(void)
create_ifch_ipc_pipes();
pid_t ifch_pid = fork();
if (ifch_pid == 0) {
close(pToNdhcR);
close(pToIfchW);
close(ifchSock[0]);
close(ifchPipe[0]);
// Don't share the RNG state with the master process.
nk_random_u32_init(&cs.rnd32_state);
ifch_main();
} else if (ifch_pid > 0) {
close(pToIfchR);
close(pToNdhcW);
close(ifchSock[1]);
close(ifchPipe[1]);
} else
suicide("failed to fork ndhc-ifch: %s", strerror(errno));
}
@@ -396,8 +377,8 @@ static void spawn_sockd(void)
create_sockd_ipc_pipes();
pid_t sockd_pid = fork();
if (sockd_pid == 0) {
close(sockdPipe[0]);
close(sockdSock[0]);
close(sockdPipe[0]);
// Don't share the RNG state with the master process.
nk_random_u32_init(&cs.rnd32_state);
sockd_main();