Stop leaking the /dev/null fd after spawning a subprocess.

[cubemap] / acceptor.cpp

diff --git a/acceptor.cpp b/acceptor.cpp
index bb3ebcb06cc3f6479a7e620c5ac37dcfb7cb7a0b..31901dd8406c97c39d97dc9b3310dedb4f37a18e 100644 (file)
--- a/acceptor.cpp
+++ b/acceptor.cpp
@@ -1,5 +1,6 @@
 #include <assert.h>
 #include <errno.h>
+#include <fcntl.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
 #include <poll.h>
@@ -21,12 +22,13 @@ extern ServerPool *servers;
 
 int create_server_socket(const sockaddr_in6 &addr, SocketType socket_type)
 {
+       // NOTE: We set as non-blocking, so the acceptor thread can notice that we want to shut it down.
        int server_sock;
        if (socket_type == TCP_SOCKET) {
-               server_sock = socket(PF_INET6, SOCK_STREAM, IPPROTO_TCP);
+               server_sock = socket(PF_INET6, SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC, IPPROTO_TCP);
        } else {
                assert(socket_type == UDP_SOCKET);
-               server_sock = socket(PF_INET6, SOCK_DGRAM, IPPROTO_UDP);
+               server_sock = socket(PF_INET6, SOCK_DGRAM | SOCK_NONBLOCK | SOCK_CLOEXEC, IPPROTO_UDP);
        }
        if (server_sock == -1) {
                log_perror("socket");
@@ -46,13 +48,7 @@ int create_server_socket(const sockaddr_in6 &addr, SocketType socket_type)
                exit(1);
        }
 
-       // Set as non-blocking, so the acceptor thread can notice that we want to shut it down.
-       if (ioctl(server_sock, FIONBIO, &one) == -1) {
-               log_perror("ioctl(FIONBIO)");
-               exit(1);
-       }
-
-       if (bind(server_sock, reinterpret_cast<const sockaddr *>(&addr), sizeof(addr)) == -1) {
+       if (::bind(server_sock, reinterpret_cast<const sockaddr *>(&addr), sizeof(addr)) == -1) {
                log_perror("bind");
                exit(1);
        }
@@ -106,10 +102,17 @@ Acceptor::Acceptor(const AcceptorProto &serialized)
          certificate_chain(serialized.certificate_chain()),
          private_key(serialized.private_key())
 {
+       // Set back the close-on-exec flag for the socket.
+       // (This can't leak into a child, since we haven't been started yet.)
+       fcntl(server_sock, F_SETFD, O_CLOEXEC);
 }
 
 AcceptorProto Acceptor::serialize() const
 {
+       // Unset the close-on-exec flag for the socket.
+       // (This can't leak into a child, since there's only one thread left.)
+       fcntl(server_sock, F_SETFD, 0);
+
        char buf[INET6_ADDRSTRLEN];
        inet_ntop(addr.sin6_family, &addr.sin6_addr, buf, sizeof(buf));
 
@@ -130,7 +133,7 @@ void Acceptor::close_socket()
 void Acceptor::do_work()
 {
        while (!should_stop()) {
-               if (!wait_for_activity(server_sock, POLLIN, NULL)) {
+               if (!wait_for_activity(server_sock, POLLIN, nullptr)) {
                        continue;
                }
 
@@ -138,7 +141,7 @@ void Acceptor::do_work()
                socklen_t addrlen = sizeof(addr);
 
                // Get a new socket, and set it as nonblocking.
-               int sock = accept4(server_sock, reinterpret_cast<sockaddr *>(&addr), &addrlen, SOCK_NONBLOCK);
+               int sock = accept4(server_sock, reinterpret_cast<sockaddr *>(&addr), &addrlen, SOCK_NONBLOCK | SOCK_CLOEXEC);
                if (sock == -1 && errno == EINTR) {
                        continue;
                }