core: when forcibly killing/aborting left-over unit processes log about it

Let's lot at LOG_NOTICE about any processes that we are going to
SIGKILL/SIGABRT because clean termination of them didn't work.

This turns the various boolean flag parameters to cg_kill(), cg_migrate() and
related calls into a single binary flags parameter, simply because the function
now gained even more parameters and the parameter listed shouldn't get too
long.

Logging for killing processes is done either when the kill signal is SIGABRT or
SIGKILL, or on explicit request if KILL_TERMINATE_AND_LOG instead of LOG_TERMINATE
is passed. This isn't used yet in this patch, but is made use of in a later
patch.

2 files changed, 56 insertions, 26 deletions

diff --git a/src/basic/cgroup-util.c b/src/basic/cgroup-util.c
index 7cdc97ee3c..630e15b141 100644
--- a/src/basic/cgroup-util.c
+++ b/src/basic/cgroup-util.c
@@ -197,7 +197,15 @@ int cg_rmdir(const char *controller, const char *path) {
         return 0;
 }
 
-int cg_kill(const char *controller, const char *path, int sig, bool sigcont, bool ignore_self, Set *s) {
+int cg_kill(
+                const char *controller,
+                const char *path,
+                int sig,
+                CGroupFlags flags,
+                Set *s,
+                cg_kill_log_func_t log_kill,
+                void *userdata) {
+
         _cleanup_set_free_ Set *allocated_set = NULL;
         bool done = false;
         int r, ret = 0;
@@ -232,19 +240,22 @@ int cg_kill(const char *controller, const char *path, int sig, bool sigcont, boo
 
                 while ((r = cg_read_pid(f, &pid)) > 0) {
 
-                        if (ignore_self && pid == my_pid)
+                        if ((flags & CGROUP_IGNORE_SELF) && pid == my_pid)
                                 continue;
 
                         if (set_get(s, PID_TO_PTR(pid)) == PID_TO_PTR(pid))
                                 continue;
 
+                        if (log_kill)
+                                log_kill(pid, sig, userdata);
+
                         /* If we haven't killed this process yet, kill
                          * it */
                         if (kill(pid, sig) < 0) {
                                 if (ret >= 0 && errno != ESRCH)
                                         ret = -errno;
                         } else {
-                                if (sigcont && sig != SIGKILL)
+                                if (flags & CGROUP_SIGCONT)
                                         (void) kill(pid, SIGCONT);
 
                                 if (ret == 0)
@@ -278,7 +289,15 @@ int cg_kill(const char *controller, const char *path, int sig, bool sigcont, boo
         return ret;
 }
 
-int cg_kill_recursive(const char *controller, const char *path, int sig, bool sigcont, bool ignore_self, bool rem, Set *s) {
+int cg_kill_recursive(
+                const char *controller,
+                const char *path,
+                int sig,
+                CGroupFlags flags,
+                Set *s,
+                cg_kill_log_func_t log_kill,
+                void *userdata) {
+
         _cleanup_set_free_ Set *allocated_set = NULL;
         _cleanup_closedir_ DIR *d = NULL;
         int r, ret;
@@ -293,7 +312,7 @@ int cg_kill_recursive(const char *controller, const char *path, int sig, bool si
                         return -ENOMEM;
         }
 
-        ret = cg_kill(controller, path, sig, sigcont, ignore_self, s);
+        ret = cg_kill(controller, path, sig, flags, s, log_kill, userdata);
 
         r = cg_enumerate_subgroups(controller, path, &d);
         if (r < 0) {
@@ -311,15 +330,14 @@ int cg_kill_recursive(const char *controller, const char *path, int sig, bool si
                 if (!p)
                         return -ENOMEM;
 
-                r = cg_kill_recursive(controller, p, sig, sigcont, ignore_self, rem, s);
+                r = cg_kill_recursive(controller, p, sig, flags, s, log_kill, userdata);
                 if (r != 0 && ret >= 0)
                         ret = r;
         }
-
         if (ret >= 0 && r < 0)
                 ret = r;
 
-        if (rem) {
+        if (flags & CGROUP_REMOVE) {
                 r = cg_rmdir(controller, path);
                 if (r < 0 && ret >= 0 && r != -ENOENT && r != -EBUSY)
                         return r;
@@ -328,7 +346,13 @@ int cg_kill_recursive(const char *controller, const char *path, int sig, bool si
         return ret;
 }
 
-int cg_migrate(const char *cfrom, const char *pfrom, const char *cto, const char *pto, bool ignore_self) {
+int cg_migrate(
+                const char *cfrom,
+                const char *pfrom,
+                const char *cto,
+                const char *pto,
+                CGroupFlags flags) {
+
         bool done = false;
         _cleanup_set_free_ Set *s = NULL;
         int r, ret = 0;
@@ -363,7 +387,7 @@ int cg_migrate(const char *cfrom, const char *pfrom, const char *cto, const char
                         /* This might do weird stuff if we aren't a
                          * single-threaded program. However, we
                          * luckily know we are not */
-                        if (ignore_self && pid == my_pid)
+                        if ((flags & CGROUP_IGNORE_SELF) && pid == my_pid)
                                 continue;
 
                         if (set_get(s, PID_TO_PTR(pid)) == PID_TO_PTR(pid))
@@ -411,8 +435,7 @@ int cg_migrate_recursive(
                 const char *pfrom,
                 const char *cto,
                 const char *pto,
-                bool ignore_self,
-                bool rem) {
+                CGroupFlags flags) {
 
         _cleanup_closedir_ DIR *d = NULL;
         int r, ret = 0;
@@ -423,7 +446,7 @@ int cg_migrate_recursive(
         assert(cto);
         assert(pto);
 
-        ret = cg_migrate(cfrom, pfrom, cto, pto, ignore_self);
+        ret = cg_migrate(cfrom, pfrom, cto, pto, flags);
 
         r = cg_enumerate_subgroups(cfrom, pfrom, &d);
         if (r < 0) {
@@ -441,7 +464,7 @@ int cg_migrate_recursive(
                 if (!p)
                         return -ENOMEM;
 
-                r = cg_migrate_recursive(cfrom, p, cto, pto, ignore_self, rem);
+                r = cg_migrate_recursive(cfrom, p, cto, pto, flags);
                 if (r != 0 && ret >= 0)
                         ret = r;
         }
@@ -449,7 +472,7 @@ int cg_migrate_recursive(
         if (r < 0 && ret >= 0)
                 ret = r;
 
-        if (rem) {
+        if (flags & CGROUP_REMOVE) {
                 r = cg_rmdir(cfrom, pfrom);
                 if (r < 0 && ret >= 0 && r != -ENOENT && r != -EBUSY)
                         return r;
@@ -463,8 +486,7 @@ int cg_migrate_recursive_fallback(
                 const char *pfrom,
                 const char *cto,
                 const char *pto,
-                bool ignore_self,
-                bool rem) {
+                CGroupFlags flags) {
 
         int r;
 
@@ -473,7 +495,7 @@ int cg_migrate_recursive_fallback(
         assert(cto);
         assert(pto);
 
-        r = cg_migrate_recursive(cfrom, pfrom, cto, pto, ignore_self, rem);
+        r = cg_migrate_recursive(cfrom, pfrom, cto, pto, flags);
         if (r < 0) {
                 char prefix[strlen(pto) + 1];
 
@@ -482,7 +504,7 @@ int cg_migrate_recursive_fallback(
                 PATH_FOREACH_PREFIX(prefix, pto) {
                         int q;
 
-                        q = cg_migrate_recursive(cfrom, pfrom, cto, prefix, ignore_self, rem);
+                        q = cg_migrate_recursive(cfrom, pfrom, cto, prefix, flags);
                         if (q >= 0)
                                 return q;
                 }
@@ -1955,7 +1977,7 @@ int cg_migrate_everywhere(CGroupMask supported, const char *from, const char *to
         int r = 0, unified;
 
         if (!path_equal(from, to))  {
-                r = cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER, from, SYSTEMD_CGROUP_CONTROLLER, to, false, true);
+                r = cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER, from, SYSTEMD_CGROUP_CONTROLLER, to, CGROUP_REMOVE);
                 if (r < 0)
                         return r;
         }
@@ -1979,7 +2001,7 @@ int cg_migrate_everywhere(CGroupMask supported, const char *from, const char *to
                 if (!p)
                         p = to;
 
-                (void) cg_migrate_recursive_fallback(SYSTEMD_CGROUP_CONTROLLER, to, cgroup_controller_to_string(c), p, false, false);
+                (void) cg_migrate_recursive_fallback(SYSTEMD_CGROUP_CONTROLLER, to, cgroup_controller_to_string(c), p, 0);
         }
 
         return 0;
diff --git a/src/basic/cgroup-util.h b/src/basic/cgroup-util.h
index 4bb5291296..14ebde5fc9 100644
--- a/src/basic/cgroup-util.h
+++ b/src/basic/cgroup-util.h
@@ -135,12 +135,20 @@ int cg_read_event(const char *controller, const char *path, const char *event,
 int cg_enumerate_subgroups(const char *controller, const char *path, DIR **_d);
 int cg_read_subgroup(DIR *d, char **fn);
 
-int cg_kill(const char *controller, const char *path, int sig, bool sigcont, bool ignore_self, Set *s);
-int cg_kill_recursive(const char *controller, const char *path, int sig, bool sigcont, bool ignore_self, bool remove, Set *s);
+typedef enum CGroupFlags {
+        CGROUP_SIGCONT     = 1,
+        CGROUP_IGNORE_SELF = 2,
+        CGROUP_REMOVE      = 4,
+} CGroupFlags;
 
-int cg_migrate(const char *cfrom, const char *pfrom, const char *cto, const char *pto, bool ignore_self);
-int cg_migrate_recursive(const char *cfrom, const char *pfrom, const char *cto, const char *pto, bool ignore_self, bool remove);
-int cg_migrate_recursive_fallback(const char *cfrom, const char *pfrom, const char *cto, const char *pto, bool ignore_self, bool rem);
+typedef void (*cg_kill_log_func_t)(pid_t pid, int sig, void *userdata);
+
+int cg_kill(const char *controller, const char *path, int sig, CGroupFlags flags, Set *s, cg_kill_log_func_t kill_log, void *userdata);
+int cg_kill_recursive(const char *controller, const char *path, int sig, CGroupFlags flags, Set *s, cg_kill_log_func_t kill_log, void *userdata);
+
+int cg_migrate(const char *cfrom, const char *pfrom, const char *cto, const char *pto, CGroupFlags flags);
+int cg_migrate_recursive(const char *cfrom, const char *pfrom, const char *cto, const char *pto, CGroupFlags flags);
+int cg_migrate_recursive_fallback(const char *cfrom, const char *pfrom, const char *cto, const char *pto, CGroupFlags flags);
 
 int cg_split_spec(const char *spec, char **controller, char **path);
 int cg_mangle_path(const char *path, char **result);