slirp: move socket pair creation in helper function
Originally, the patch was fixing a bunch of issues, but Peter beat me to it with earlier commit "slirp: fork_exec(): create and connect child socket before fork()". Factor out socket pair creation, to simplify the fork_exec() code. Use the name socketpair_with_oob() since the code is actually similar to what socketpair() would do, except that it uses TCP sockets, for SLIRP to be able to call send with MSG_OOB (since SO_OOBINLINE is set, this could probably be faked instead on regular unix sockets though). Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
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parent
9a50b0e0b8
commit
7f5140929b
120
slirp/misc.c
120
slirp/misc.c
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@ -73,64 +73,74 @@ fork_exec(struct socket *so, const char *ex)
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#else
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/*
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* XXX This is ugly
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* We create and bind a socket, then fork off to another
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* process, which connects to this socket, after which we
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* exec the wanted program. If something (strange) happens,
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* the accept() call could block us forever.
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*/
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int
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fork_exec(struct socket *so, const char *ex)
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static int
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slirp_socketpair_with_oob(int sv[2])
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{
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int s, cs;
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struct sockaddr_in addr, csaddr;
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struct sockaddr_in addr = {
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.sin_family = AF_INET,
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.sin_port = 0,
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.sin_addr.s_addr = INADDR_ANY,
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};
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socklen_t addrlen = sizeof(addr);
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socklen_t csaddrlen = sizeof(csaddr);
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int opt;
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char **argv;
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int ret;
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pid_t pid;
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DEBUG_CALL("fork_exec");
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DEBUG_ARG("so = %p", so);
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DEBUG_ARG("ex = %p", ex);
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addr.sin_family = AF_INET;
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addr.sin_port = 0;
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addr.sin_addr.s_addr = INADDR_ANY;
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int ret, s;
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sv[1] = -1;
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s = qemu_socket(AF_INET, SOCK_STREAM, 0);
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if (s < 0 || bind(s, (struct sockaddr *)&addr, addrlen) < 0 ||
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listen(s, 1) < 0) {
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error_report("Error: inet socket: %s", strerror(errno));
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if (s >= 0) {
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closesocket(s);
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}
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return 0;
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listen(s, 1) < 0 ||
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getsockname(s, (struct sockaddr *)&addr, &addrlen) < 0) {
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goto err;
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}
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if (getsockname(s, (struct sockaddr *)&csaddr, &csaddrlen) < 0) {
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closesocket(s);
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return 0;
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sv[1] = qemu_socket(AF_INET, SOCK_STREAM, 0);
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if (sv[1] < 0) {
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goto err;
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}
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cs = qemu_socket(AF_INET, SOCK_STREAM, 0);
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if (cs < 0) {
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closesocket(s);
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return 0;
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}
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csaddr.sin_addr = loopback_addr;
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/*
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* This connect won't block because we've already listen()ed on
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* the server end (even though we won't accept() the connection
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* until later on).
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*/
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do {
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ret = connect(cs, (struct sockaddr *)&csaddr, csaddrlen);
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ret = connect(sv[1], (struct sockaddr *)&addr, addrlen);
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} while (ret < 0 && errno == EINTR);
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if (ret < 0) {
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goto err;
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}
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do {
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sv[0] = accept(s, (struct sockaddr *)&addr, &addrlen);
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} while (sv[0] < 0 && errno == EINTR);
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if (sv[0] < 0) {
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goto err;
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}
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closesocket(s);
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closesocket(cs);
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return 0;
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err:
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error_report("Error: slirp_socketpair(): %s", strerror(errno));
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if (s >= 0) {
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closesocket(s);
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}
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if (sv[1] >= 0) {
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closesocket(sv[1]);
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}
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return -1;
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}
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int
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fork_exec(struct socket *so, const char *ex)
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{
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char **argv;
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int opt, c, sp[2];
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pid_t pid;
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DEBUG_CALL("fork_exec");
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DEBUG_ARG("so = %p", so);
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DEBUG_ARG("ex = %p", ex);
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if (slirp_socketpair_with_oob(sp) < 0) {
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return 0;
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}
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@ -138,20 +148,17 @@ fork_exec(struct socket *so, const char *ex)
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switch(pid) {
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case -1:
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error_report("Error: fork failed: %s", strerror(errno));
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closesocket(cs);
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close(s);
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closesocket(sp[0]);
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closesocket(sp[1]);
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return 0;
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case 0:
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setsid();
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/* Set the DISPLAY */
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close(s);
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dup2(cs, 0);
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dup2(cs, 1);
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dup2(cs, 2);
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for (s = getdtablesize() - 1; s >= 3; s--)
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close(s);
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dup2(sp[1], 0);
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dup2(sp[1], 1);
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dup2(sp[1], 2);
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for (c = getdtablesize() - 1; c >= 3; c--)
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close(c);
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argv = g_strsplit(ex, " ", -1);
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execvp(argv[0], (char **)argv);
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@ -163,16 +170,9 @@ fork_exec(struct socket *so, const char *ex)
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exit(1);
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default:
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so->s = sp[0];
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closesocket(sp[1]);
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qemu_add_child_watch(pid);
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closesocket(cs);
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/*
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* This should never block, because we already connect()ed
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* on the child end before we forked.
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*/
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do {
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so->s = accept(s, (struct sockaddr *)&addr, &addrlen);
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} while (so->s < 0 && errno == EINTR);
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closesocket(s);
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socket_set_fast_reuse(so->s);
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opt = 1;
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qemu_setsockopt(so->s, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(int));
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