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authorPaolo Bonzini <pbonzini@redhat.com>2017-03-16 16:29:45 +0100
committerPaolo Bonzini <pbonzini@redhat.com>2017-03-19 11:12:12 +0100
commit53fabd4b86e15869e13fb762686d674c64294385 (patch)
tree8ffb29b28fd121ab3d695e6e89cdd3bef9a6df4b /util/systemd.c
parentebedf0f9cd46b617df331eecc857c379d574ac62 (diff)
qemu-ga: obey LISTEN_PID when using systemd socket activation
qemu-ga's socket activation support was not obeying the LISTEN_PID environment variable, which avoids that a process uses a socket-activation file descriptor meant for its parent. Mess can for example ensue if a process forks a children before consuming the socket-activation file descriptor and therefore setting O_CLOEXEC on it. Luckily, qemu-nbd also got socket activation code, and its copy does support LISTEN_PID. Some extra fixups are needed to ensure that the code can be used for both, but that's what this patch does. The main change is to replace get_listen_fds's "consume" argument with the FIRST_SOCKET_ACTIVATION_FD macro from the qemu-nbd code. Cc: "Richard W.M. Jones" <rjones@redhat.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'util/systemd.c')
-rw-r--r--util/systemd.c77
1 files changed, 77 insertions, 0 deletions
diff --git a/util/systemd.c b/util/systemd.c
new file mode 100644
index 0000000000..d22e86c707
--- /dev/null
+++ b/util/systemd.c
@@ -0,0 +1,77 @@
+/*
+ * systemd socket activation support
+ *
+ * Copyright 2017 Red Hat, Inc. and/or its affiliates
+ *
+ * Authors:
+ * Richard W.M. Jones <rjones@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/systemd.h"
+#include "qemu/cutils.h"
+#include "qemu/error-report.h"
+
+#ifndef _WIN32
+unsigned int check_socket_activation(void)
+{
+ const char *s;
+ unsigned long pid;
+ unsigned long nr_fds;
+ unsigned int i;
+ int fd;
+ int err;
+
+ s = getenv("LISTEN_PID");
+ if (s == NULL) {
+ return 0;
+ }
+ err = qemu_strtoul(s, NULL, 10, &pid);
+ if (err) {
+ return 0;
+ }
+ if (pid != getpid()) {
+ return 0;
+ }
+
+ s = getenv("LISTEN_FDS");
+ if (s == NULL) {
+ return 0;
+ }
+ err = qemu_strtoul(s, NULL, 10, &nr_fds);
+ if (err) {
+ return 0;
+ }
+ assert(nr_fds <= UINT_MAX);
+
+ /* So these are not passed to any child processes we might start. */
+ unsetenv("LISTEN_FDS");
+ unsetenv("LISTEN_PID");
+
+ /* So the file descriptors don't leak into child processes. */
+ for (i = 0; i < nr_fds; ++i) {
+ fd = FIRST_SOCKET_ACTIVATION_FD + i;
+ if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1) {
+ /* If we cannot set FD_CLOEXEC then it probably means the file
+ * descriptor is invalid, so socket activation has gone wrong
+ * and we should exit.
+ */
+ error_report("Socket activation failed: "
+ "invalid file descriptor fd = %d: %m",
+ fd);
+ exit(EXIT_FAILURE);
+ }
+ }
+
+ return (unsigned int) nr_fds;
+}
+
+#else /* !_WIN32 */
+unsigned int check_socket_activation(void)
+{
+ return 0;
+}
+#endif