systemd/watch_resolv.conf_for_become_changed.patch

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---
src/core/manager.c | 103 +++++++++++++++++++++++++++++++++++++++++++++++++++++
src/core/manager.h | 5 ++
2 files changed, 108 insertions(+)
--- src/core/manager.c
+++ src/core/manager.c 2014-11-07 11:12:58.334193988 +0000
@@ -37,6 +37,7 @@
#include <sys/stat.h>
#include <dirent.h>
#include <sys/timerfd.h>
+#include <resolv.h>
#ifdef HAVE_AUDIT
#include <libaudit.h>
@@ -304,6 +305,101 @@ static int manager_check_ask_password(Ma
return m->have_ask_password;
}
+static int manager_setup_resolv_conf_change(Manager *);
+
+static int manager_dispatch_resolv_conf_fd(sd_event_source *source,
+ int fd, uint32_t revents, void *userdata) {
+ Manager *m = userdata;
+
+ assert(m);
+ assert(m->resolv_conf_inotify_fd == fd);
+
+ if (revents != EPOLLIN) {
+ log_warning("Got unexpected poll event for notify fd.");
+ return 0;
+ }
+
+ if (fd >= 0)
+ flush_fd(fd);
+
+ m->resolv_conf_event_source = sd_event_source_unref(m->resolv_conf_event_source);
+
+ if (m->resolv_conf_inotify_fd >= 0)
+ close_nointr_nofail(m->resolv_conf_inotify_fd);
+ m->resolv_conf_inotify_fd = -1;
+
+ manager_setup_resolv_conf_change(m);
+
+ return m->resolv_conf_noent ? 0 : res_init();
+}
+
+static int manager_setup_resolv_conf_change(Manager *m) {
+ int r;
+
+ assert(m);
+ assert(m->resolv_conf_inotify_fd < 0);
+
+ m->resolv_conf_inotify_fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC);
+ if (m->resolv_conf_inotify_fd < 0) {
+ log_error("inotify_init1() failed: %m");
+ r = -errno;
+ goto fail;
+ }
+ if (inotify_add_watch(m->resolv_conf_inotify_fd, "/etc/resolv.conf",
+ IN_CLOSE_WRITE|IN_MODIFY|IN_ATTRIB|IN_DELETE_SELF) < 0) {
+ if (errno == ENOENT) {
+ m->resolv_conf_noent = true;
+ if (inotify_add_watch(m->resolv_conf_inotify_fd, "/etc", IN_CREATE|IN_MOVED_TO) < 0) {
+ log_error("Failed to add watch on /etc: %m");
+ r = -errno;
+ goto fail;
+ }
+ } else {
+ log_error("Failed to add watch on /etc/resolv.conf: %m");
+ r = -errno;
+ goto fail;
+ }
+ }
+ if (inotify_add_watch(m->resolv_conf_inotify_fd, "/etc/host.conf",
+ IN_CLOSE_WRITE|IN_MODIFY|IN_ATTRIB|IN_DELETE_SELF) < 0 && errno != ENOENT) {
+ log_error("Failed to add watch on /etc/host.conf: %m");
+ r = -errno;
+ goto fail;
+ }
+
+ r = sd_event_add_io(m->event, &m->resolv_conf_event_source,
+ m->resolv_conf_inotify_fd, EPOLLIN,
+ manager_dispatch_resolv_conf_fd, m);
+ if (r < 0) {
+ log_error("Failed to add event source for resolver: %s", strerror(-r));
+ goto fail;
+ }
+
+ r = sd_event_source_set_priority(m->resolv_conf_event_source, -10);
+ if (r < 0) {
+ log_error("Failed to add event source for resolver: %s", strerror(-r));
+ m->resolv_conf_event_source = sd_event_source_unref(m->resolv_conf_event_source);
+ goto fail;
+ }
+
+ return 0;
+fail:
+ if (m->resolv_conf_inotify_fd >= 0)
+ close_nointr_nofail(m->resolv_conf_inotify_fd);
+ m->resolv_conf_inotify_fd = -1;
+
+ return 0; /* Ignore error here */
+}
+
+static void manager_shutdown_resolv_conf_change(Manager *m) {
+ assert(m);
+
+ m->resolv_conf_event_source = sd_event_source_unref(m->resolv_conf_event_source);
+ if (m->resolv_conf_inotify_fd >= 0)
+ close_nointr_nofail(m->resolv_conf_inotify_fd);
+ m->resolv_conf_inotify_fd = -1;
+}
+
static int manager_watch_idle_pipe(Manager *m) {
int r;
@@ -562,6 +658,7 @@ int manager_new(SystemdRunningAs running
m->pin_cgroupfs_fd = m->notify_fd = m->signal_fd = m->time_change_fd = m->dev_autofs_fd = m->private_listen_fd = m->kdbus_fd = -1;
m->current_job_id = 1; /* start as id #1, so that we can leave #0 around as "null-like" value */
+ m->resolv_conf_inotify_fd = -1;
m->ask_password_inotify_fd = -1;
m->have_ask_password = -EINVAL; /* we don't know */
@@ -613,6 +710,10 @@ int manager_new(SystemdRunningAs running
if (r < 0)
goto fail;
+ r = manager_setup_resolv_conf_change(m);
+ if (r < 0)
+ goto fail;
+
m->udev = udev_new();
if (!m->udev) {
r = -ENOMEM;
@@ -906,6 +1007,8 @@ void manager_free(Manager *m) {
assert(m);
+ manager_shutdown_resolv_conf_change(m);
+
manager_clear_jobs_and_units(m);
for (c = 0; c < _UNIT_TYPE_MAX; c++)
--- src/core/manager.h
+++ src/core/manager.h 2014-11-07 11:06:41.466019636 +0000
@@ -157,6 +157,11 @@ struct Manager {
FILE *proc_self_mountinfo;
sd_event_source *mount_event_source;
+ /* Watch out any change of /etc/resolv.conf */
+ int resolv_conf_inotify_fd;
+ sd_event_source *resolv_conf_event_source;
+ bool resolv_conf_noent;
+
/* Data specific to the swap filesystem */
FILE *proc_swaps;
sd_event_source *swap_event_source;