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authorMarc-André Lureau <marcandre.lureau@redhat.com>2018-11-14 16:36:03 +0400
committerSamuel Thibault <samuel.thibault@ens-lyon.org>2019-01-14 00:40:54 +0100
commit7f5140929bef33e833b99e02f7b8dceb7b7aa123 (patch)
tree9ce10e5ee3be92aea267d6601a2486a1d5fe5d52 /slirp/misc.c
parent9a50b0e0b80faf8f4e53d3f7e73144421561a7c8 (diff)
downloadqemu-arm-7f5140929bef33e833b99e02f7b8dceb7b7aa123.tar.gz
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>
Diffstat (limited to 'slirp/misc.c')
-rw-r--r--slirp/misc.c142
1 files changed, 71 insertions, 71 deletions
diff --git a/slirp/misc.c b/slirp/misc.c
index 4840187750..7362e14339 100644
--- a/slirp/misc.c
+++ b/slirp/misc.c
@@ -73,85 +73,92 @@ fork_exec(struct socket *so, const char *ex)
#else
-/*
- * XXX This is ugly
- * We create and bind a socket, then fork off to another
- * process, which connects to this socket, after which we
- * exec the wanted program. If something (strange) happens,
- * the accept() call could block us forever.
- */
+static int
+slirp_socketpair_with_oob(int sv[2])
+{
+ struct sockaddr_in addr = {
+ .sin_family = AF_INET,
+ .sin_port = 0,
+ .sin_addr.s_addr = INADDR_ANY,
+ };
+ socklen_t addrlen = sizeof(addr);
+ int ret, s;
+
+ sv[1] = -1;
+ s = qemu_socket(AF_INET, SOCK_STREAM, 0);
+ if (s < 0 || bind(s, (struct sockaddr *)&addr, addrlen) < 0 ||
+ listen(s, 1) < 0 ||
+ getsockname(s, (struct sockaddr *)&addr, &addrlen) < 0) {
+ goto err;
+ }
+
+ sv[1] = qemu_socket(AF_INET, SOCK_STREAM, 0);
+ if (sv[1] < 0) {
+ goto err;
+ }
+ /*
+ * This connect won't block because we've already listen()ed on
+ * the server end (even though we won't accept() the connection
+ * until later on).
+ */
+ do {
+ ret = connect(sv[1], (struct sockaddr *)&addr, addrlen);
+ } while (ret < 0 && errno == EINTR);
+ if (ret < 0) {
+ goto err;
+ }
+
+ do {
+ sv[0] = accept(s, (struct sockaddr *)&addr, &addrlen);
+ } while (sv[0] < 0 && errno == EINTR);
+ if (sv[0] < 0) {
+ goto err;
+ }
+
+ closesocket(s);
+ return 0;
+
+err:
+ error_report("Error: slirp_socketpair(): %s", strerror(errno));
+ if (s >= 0) {
+ closesocket(s);
+ }
+ if (sv[1] >= 0) {
+ closesocket(sv[1]);
+ }
+ return -1;
+}
+
int
fork_exec(struct socket *so, const char *ex)
{
- int s, cs;
- struct sockaddr_in addr, csaddr;
- socklen_t addrlen = sizeof(addr);
- socklen_t csaddrlen = sizeof(csaddr);
- int opt;
char **argv;
- int ret;
+ int opt, c, sp[2];
pid_t pid;
DEBUG_CALL("fork_exec");
DEBUG_ARG("so = %p", so);
DEBUG_ARG("ex = %p", ex);
- addr.sin_family = AF_INET;
- addr.sin_port = 0;
- addr.sin_addr.s_addr = INADDR_ANY;
-
- s = qemu_socket(AF_INET, SOCK_STREAM, 0);
- if (s < 0 || bind(s, (struct sockaddr *)&addr, addrlen) < 0 ||
- listen(s, 1) < 0) {
- error_report("Error: inet socket: %s", strerror(errno));
- if (s >= 0) {
- closesocket(s);
- }
+ if (slirp_socketpair_with_oob(sp) < 0) {
return 0;
}
- if (getsockname(s, (struct sockaddr *)&csaddr, &csaddrlen) < 0) {
- closesocket(s);
- return 0;
- }
- cs = qemu_socket(AF_INET, SOCK_STREAM, 0);
- if (cs < 0) {
- closesocket(s);
- return 0;
- }
- csaddr.sin_addr = loopback_addr;
- /*
- * This connect won't block because we've already listen()ed on
- * the server end (even though we won't accept() the connection
- * until later on).
- */
- do {
- ret = connect(cs, (struct sockaddr *)&csaddr, csaddrlen);
- } while (ret < 0 && errno == EINTR);
- if (ret < 0) {
- closesocket(s);
- closesocket(cs);
- return 0;
- }
-
pid = fork();
switch(pid) {
case -1:
error_report("Error: fork failed: %s", strerror(errno));
- closesocket(cs);
- close(s);
+ closesocket(sp[0]);
+ closesocket(sp[1]);
return 0;
case 0:
- setsid();
-
- /* Set the DISPLAY */
- close(s);
- dup2(cs, 0);
- dup2(cs, 1);
- dup2(cs, 2);
- for (s = getdtablesize() - 1; s >= 3; s--)
- close(s);
+ setsid();
+ dup2(sp[1], 0);
+ dup2(sp[1], 1);
+ dup2(sp[1], 2);
+ for (c = getdtablesize() - 1; c >= 3; c--)
+ close(c);
argv = g_strsplit(ex, " ", -1);
execvp(argv[0], (char **)argv);
@@ -163,19 +170,12 @@ fork_exec(struct socket *so, const char *ex)
exit(1);
default:
+ so->s = sp[0];
+ closesocket(sp[1]);
qemu_add_child_watch(pid);
- closesocket(cs);
- /*
- * This should never block, because we already connect()ed
- * on the child end before we forked.
- */
- do {
- so->s = accept(s, (struct sockaddr *)&addr, &addrlen);
- } while (so->s < 0 && errno == EINTR);
- closesocket(s);
- socket_set_fast_reuse(so->s);
- opt = 1;
- qemu_setsockopt(so->s, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(int));
+ socket_set_fast_reuse(so->s);
+ opt = 1;
+ qemu_setsockopt(so->s, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(int));
qemu_set_nonblock(so->s);
return 1;
}