From f64f2386011b75b59a118300f57478c80b031652 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 13 Apr 2012 23:24:47 +0200
Subject: [PATCH] service: place control command in subcgroup control/
Previously, we were brutally and onconditionally killing all processes
in a service's cgroup before starting the service anew, in order to
ensure that StartPre lines cannot be misused to spawn long-running
processes.
On logind-less systems this has the effect that restarting sshd
necessarily calls all active ssh sessions, which is usually not
desirable.
With this patch control processes for a service are placed in a
sub-cgroup called "control/". When starting a service anew we simply
kill this cgroup, but not the main cgroup, in order to avoid killing any
long-running non-control processes from previous runs.
https://bugzilla.redhat.com/show_bug.cgi?id=805942
(cherry picked from commit ecedd90fcdf647f9a7b56b4934b65e30b2979b04)
Conflicts:
TODO
---
src/core/cgroup.c | 52 +++++++++++++---
src/core/cgroup.h | 8 +--
src/core/execute.c | 5 +-
src/core/execute.h | 1 +
src/core/mount.c | 7 ++-
src/core/service.c | 175 +++++++++++++++++++++++++++++-----------------------
src/core/socket.c | 7 ++-
src/core/swap.c | 7 ++-
8 files changed, 163 insertions(+), 99 deletions(-)
diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index 1f6139e..a4eb6ed 100644
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -108,26 +108,43 @@ void cgroup_bonding_trim_list(CGroupBonding *first, bool delete_root) {
cgroup_bonding_trim(b, delete_root);
}
-int cgroup_bonding_install(CGroupBonding *b, pid_t pid) {
+
+int cgroup_bonding_install(CGroupBonding *b, pid_t pid, const char *cgroup_suffix) {
+ char *p = NULL;
+ const char *path;
int r;
assert(b);
assert(pid >= 0);
- if ((r = cg_create_and_attach(b->controller, b->path, pid)) < 0)
+ if (cgroup_suffix) {
+ p = join(b->path, "/", cgroup_suffix, NULL);
+ if (!p)
+ return -ENOMEM;
+
+ path = p;
+ } else
+ path = b->path;
+
+ r = cg_create_and_attach(b->controller, path, pid);
+ free(p);
+
+ if (r < 0)
return r;
b->realized = true;
return 0;
}
-int cgroup_bonding_install_list(CGroupBonding *first, pid_t pid) {
+int cgroup_bonding_install_list(CGroupBonding *first, pid_t pid, const char *cgroup_suffix) {
CGroupBonding *b;
int r;
- LIST_FOREACH(by_unit, b, first)
- if ((r = cgroup_bonding_install(b, pid)) < 0 && b->essential)
+ LIST_FOREACH(by_unit, b, first) {
+ r = cgroup_bonding_install(b, pid, cgroup_suffix);
+ if (r < 0 && b->essential)
return r;
+ }
return 0;
}
@@ -176,7 +193,11 @@ int cgroup_bonding_set_task_access_list(CGroupBonding *first, mode_t mode, uid_t
return 0;
}
-int cgroup_bonding_kill(CGroupBonding *b, int sig, bool sigcont, Set *s) {
+int cgroup_bonding_kill(CGroupBonding *b, int sig, bool sigcont, Set *s, const char *cgroup_suffix) {
+ char *p = NULL;
+ const char *path;
+ int r;
+
assert(b);
assert(sig >= 0);
@@ -184,10 +205,22 @@ int cgroup_bonding_kill(CGroupBonding *b, int sig, bool sigcont, Set *s) {
if (!b->ours)
return 0;
- return cg_kill_recursive(b->controller, b->path, sig, sigcont, true, false, s);
+ if (cgroup_suffix) {
+ p = join(b->path, "/", cgroup_suffix, NULL);
+ if (!p)
+ return -ENOMEM;
+
+ path = p;
+ } else
+ path = b->path;
+
+ r = cg_kill_recursive(b->controller, path, sig, sigcont, true, false, s);
+ free(p);
+
+ return r;
}
-int cgroup_bonding_kill_list(CGroupBonding *first, int sig, bool sigcont, Set *s) {
+int cgroup_bonding_kill_list(CGroupBonding *first, int sig, bool sigcont, Set *s, const char *cgroup_suffix) {
CGroupBonding *b;
Set *allocated_set = NULL;
int ret = -EAGAIN, r;
@@ -200,7 +233,8 @@ int cgroup_bonding_kill_list(CGroupBonding *first, int sig, bool sigcont, Set *s
return -ENOMEM;
LIST_FOREACH(by_unit, b, first) {
- if ((r = cgroup_bonding_kill(b, sig, sigcont, s)) < 0) {
+ r = cgroup_bonding_kill(b, sig, sigcont, s, cgroup_suffix);
+ if (r < 0) {
if (r == -EAGAIN || r == -ESRCH)
continue;
diff --git a/src/core/cgroup.h b/src/core/cgroup.h
index 5faa7dc..35ae52b 100644
--- a/src/core/cgroup.h
+++ b/src/core/cgroup.h
@@ -56,8 +56,8 @@ int cgroup_bonding_realize_list(CGroupBonding *first);
void cgroup_bonding_free(CGroupBonding *b, bool trim);
void cgroup_bonding_free_list(CGroupBonding *first, bool trim);
-int cgroup_bonding_install(CGroupBonding *b, pid_t pid);
-int cgroup_bonding_install_list(CGroupBonding *first, pid_t pid);
+int cgroup_bonding_install(CGroupBonding *b, pid_t pid, const char *suffix);
+int cgroup_bonding_install_list(CGroupBonding *first, pid_t pid, const char *suffix);
int cgroup_bonding_set_group_access(CGroupBonding *b, mode_t mode, uid_t uid, gid_t gid);
int cgroup_bonding_set_group_access_list(CGroupBonding *b, mode_t mode, uid_t uid, gid_t gid);
@@ -65,8 +65,8 @@ int cgroup_bonding_set_group_access_list(CGroupBonding *b, mode_t mode, uid_t ui
int cgroup_bonding_set_task_access(CGroupBonding *b, mode_t mode, uid_t uid, gid_t gid, int sticky);
int cgroup_bonding_set_task_access_list(CGroupBonding *b, mode_t mode, uid_t uid, gid_t gid, int sticky);
-int cgroup_bonding_kill(CGroupBonding *b, int sig, bool sigcont, Set *s);
-int cgroup_bonding_kill_list(CGroupBonding *first, int sig, bool sigcont, Set *s);
+int cgroup_bonding_kill(CGroupBonding *b, int sig, bool sigcont, Set *s, const char *suffix);
+int cgroup_bonding_kill_list(CGroupBonding *first, int sig, bool sigcont, Set *s, const char *suffix);
void cgroup_bonding_trim(CGroupBonding *first, bool delete_root);
void cgroup_bonding_trim_list(CGroupBonding *first, bool delete_root);
diff --git a/src/core/execute.c b/src/core/execute.c
index 143ff35..be94ba5 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -962,6 +962,7 @@ int exec_spawn(ExecCommand *command,
bool confirm_spawn,
CGroupBonding *cgroup_bondings,
CGroupAttribute *cgroup_attributes,
+ const char *cgroup_suffix,
pid_t *ret) {
pid_t pid;
@@ -1154,7 +1155,7 @@ int exec_spawn(ExecCommand *command,
}
if (cgroup_bondings) {
- err = cgroup_bonding_install_list(cgroup_bondings, 0);
+ err = cgroup_bonding_install_list(cgroup_bondings, 0, cgroup_suffix);
if (err < 0) {
r = EXIT_CGROUP;
goto fail_child;
@@ -1505,7 +1506,7 @@ int exec_spawn(ExecCommand *command,
* sure that when we kill the cgroup the process will be
* killed too). */
if (cgroup_bondings)
- cgroup_bonding_install_list(cgroup_bondings, pid);
+ cgroup_bonding_install_list(cgroup_bondings, pid, cgroup_suffix);
log_debug("Forked %s as %lu", command->path, (unsigned long) pid);
diff --git a/src/core/execute.h b/src/core/execute.h
index 0d7e7dd..b8522a0 100644
--- a/src/core/execute.h
+++ b/src/core/execute.h
@@ -192,6 +192,7 @@ int exec_spawn(ExecCommand *command,
bool confirm_spawn,
struct CGroupBonding *cgroup_bondings,
struct CGroupAttribute *cgroup_attributes,
+ const char *cgroup_suffix,
pid_t *ret);
void exec_command_done(ExecCommand *c);
diff --git a/src/core/mount.c b/src/core/mount.c
index 7dbeaf9..ca63a49 100644
--- a/src/core/mount.c
+++ b/src/core/mount.c
@@ -805,6 +805,7 @@ static int mount_spawn(Mount *m, ExecCommand *c, pid_t *_pid) {
UNIT(m)->manager->confirm_spawn,
UNIT(m)->cgroup_bondings,
UNIT(m)->cgroup_attributes,
+ NULL,
&pid)) < 0)
goto fail;
@@ -875,7 +876,8 @@ static void mount_enter_signal(Mount *m, MountState state, MountResult f) {
if ((r = set_put(pid_set, LONG_TO_PTR(m->control_pid))) < 0)
goto fail;
- if ((r = cgroup_bonding_kill_list(UNIT(m)->cgroup_bondings, sig, true, pid_set)) < 0) {
+ r = cgroup_bonding_kill_list(UNIT(m)->cgroup_bondings, sig, true, pid_set, NULL);
+ if (r < 0) {
if (r != -EAGAIN && r != -ESRCH && r != -ENOENT)
log_warning("Failed to kill control group: %s", strerror(-r));
} else if (r > 0)
@@ -1833,7 +1835,8 @@ static int mount_kill(Unit *u, KillWho who, KillMode mode, int signo, DBusError
goto finish;
}
- if ((q = cgroup_bonding_kill_list(UNIT(m)->cgroup_bondings, signo, false, pid_set)) < 0)
+ q = cgroup_bonding_kill_list(UNIT(m)->cgroup_bondings, signo, false, pid_set, NULL);
+ if (q < 0)
if (q != -EAGAIN && q != -ESRCH && q != -ENOENT)
r = q;
}
diff --git a/src/core/service.c b/src/core/service.c
index 8b5c0b0..807ffb9 100644
--- a/src/core/service.c
+++ b/src/core/service.c
@@ -1686,6 +1686,7 @@ static int service_spawn(
bool apply_chroot,
bool apply_tty_stdin,
bool set_notify_socket,
+ bool is_control,
pid_t *_pid) {
pid_t pid;
@@ -1767,6 +1768,7 @@ static int service_spawn(
UNIT(s)->manager->confirm_spawn,
UNIT(s)->cgroup_bondings,
UNIT(s)->cgroup_attributes,
+ is_control ? "control" : NULL,
&pid);
if (r < 0)
@@ -1886,15 +1888,17 @@ static void service_enter_stop_post(Service *s, ServiceResult f) {
if ((s->control_command = s->exec_command[SERVICE_EXEC_STOP_POST])) {
s->control_command_id = SERVICE_EXEC_STOP_POST;
- if ((r = service_spawn(s,
- s->control_command,
- true,
- false,
- !s->permissions_start_only,
- !s->root_directory_start_only,
- true,
- false,
- &s->control_pid)) < 0)
+ r = service_spawn(s,
+ s->control_command,
+ true,
+ false,
+ !s->permissions_start_only,
+ !s->root_directory_start_only,
+ true,
+ false,
+ true,
+ &s->control_pid);
+ if (r < 0)
goto fail;
@@ -1952,7 +1956,8 @@ static void service_enter_signal(Service *s, ServiceState state, ServiceResult f
if ((r = set_put(pid_set, LONG_TO_PTR(s->control_pid))) < 0)
goto fail;
- if ((r = cgroup_bonding_kill_list(UNIT(s)->cgroup_bondings, sig, true, pid_set)) < 0) {
+ r = cgroup_bonding_kill_list(UNIT(s)->cgroup_bondings, sig, true, pid_set, NULL);
+ if (r < 0) {
if (r != -EAGAIN && r != -ESRCH && r != -ENOENT)
log_warning("Failed to kill control group: %s", strerror(-r));
} else if (r > 0)
@@ -2001,15 +2006,17 @@ static void service_enter_stop(Service *s, ServiceResult f) {
if ((s->control_command = s->exec_command[SERVICE_EXEC_STOP])) {
s->control_command_id = SERVICE_EXEC_STOP;
- if ((r = service_spawn(s,
- s->control_command,
- true,
- false,
- !s->permissions_start_only,
- !s->root_directory_start_only,
- false,
- false,
- &s->control_pid)) < 0)
+ r = service_spawn(s,
+ s->control_command,
+ true,
+ false,
+ !s->permissions_start_only,
+ !s->root_directory_start_only,
+ false,
+ false,
+ true,
+ &s->control_pid);
+ if (r < 0)
goto fail;
service_set_state(s, SERVICE_STOP);
@@ -2054,15 +2061,17 @@ static void service_enter_start_post(Service *s) {
if ((s->control_command = s->exec_command[SERVICE_EXEC_START_POST])) {
s->control_command_id = SERVICE_EXEC_START_POST;
- if ((r = service_spawn(s,
- s->control_command,
- true,
- false,
- !s->permissions_start_only,
- !s->root_directory_start_only,
- false,
- false,
- &s->control_pid)) < 0)
+ r = service_spawn(s,
+ s->control_command,
+ true,
+ false,
+ !s->permissions_start_only,
+ !s->root_directory_start_only,
+ false,
+ false,
+ true,
+ &s->control_pid);
+ if (r < 0)
goto fail;
service_set_state(s, SERVICE_START_POST);
@@ -2094,7 +2103,7 @@ static void service_enter_start(Service *s) {
/* We want to ensure that nobody leaks processes from
* START_PRE here, so let's go on a killing spree, People
* should not spawn long running processes from START_PRE. */
- cgroup_bonding_kill_list(UNIT(s)->cgroup_bondings, SIGKILL, true, NULL);
+ cgroup_bonding_kill_list(UNIT(s)->cgroup_bondings, SIGKILL, true, NULL, "control");
if (s->type == SERVICE_FORKING) {
s->control_command_id = SERVICE_EXEC_START;
@@ -2108,15 +2117,17 @@ static void service_enter_start(Service *s) {
c = s->main_command = s->exec_command[SERVICE_EXEC_START];
}
- if ((r = service_spawn(s,
- c,
- s->type == SERVICE_FORKING || s->type == SERVICE_DBUS || s->type == SERVICE_NOTIFY,
- true,
- true,
- true,
- true,
- s->notify_access != NOTIFY_NONE,
- &pid)) < 0)
+ r = service_spawn(s,
+ c,
+ s->type == SERVICE_FORKING || s->type == SERVICE_DBUS || s->type == SERVICE_NOTIFY,
+ true,
+ true,
+ true,
+ true,
+ s->notify_access != NOTIFY_NONE,
+ false,
+ &pid);
+ if (r < 0)
goto fail;
if (s->type == SERVICE_SIMPLE) {
@@ -2168,19 +2179,21 @@ static void service_enter_start_pre(Service *s) {
/* Before we start anything, let's clear up what might
* be left from previous runs. */
- cgroup_bonding_kill_list(UNIT(s)->cgroup_bondings, SIGKILL, true, NULL);
+ cgroup_bonding_kill_list(UNIT(s)->cgroup_bondings, SIGKILL, true, NULL, "control");
s->control_command_id = SERVICE_EXEC_START_PRE;
- if ((r = service_spawn(s,
- s->control_command,
- true,
- false,
- !s->permissions_start_only,
- !s->root_directory_start_only,
- true,
- false,
- &s->control_pid)) < 0)
+ r = service_spawn(s,
+ s->control_command,
+ true,
+ false,
+ !s->permissions_start_only,
+ !s->root_directory_start_only,
+ true,
+ false,
+ true,
+ &s->control_pid);
+ if (r < 0)
goto fail;
service_set_state(s, SERVICE_START_PRE);
@@ -2233,15 +2246,17 @@ static void service_enter_reload(Service *s) {
if ((s->control_command = s->exec_command[SERVICE_EXEC_RELOAD])) {
s->control_command_id = SERVICE_EXEC_RELOAD;
- if ((r = service_spawn(s,
- s->control_command,
- true,
- false,
- !s->permissions_start_only,
- !s->root_directory_start_only,
- false,
- false,
- &s->control_pid)) < 0)
+ r = service_spawn(s,
+ s->control_command,
+ true,
+ false,
+ !s->permissions_start_only,
+ !s->root_directory_start_only,
+ false,
+ false,
+ true,
+ &s->control_pid);
+ if (r < 0)
goto fail;
service_set_state(s, SERVICE_RELOAD);
@@ -2268,16 +2283,18 @@ static void service_run_next_control(Service *s) {
s->control_command = s->control_command->command_next;
service_unwatch_control_pid(s);
- if ((r = service_spawn(s,
- s->control_command,
- true,
- false,
- !s->permissions_start_only,
- !s->root_directory_start_only,
- s->control_command_id == SERVICE_EXEC_START_PRE ||
- s->control_command_id == SERVICE_EXEC_STOP_POST,
- false,
- &s->control_pid)) < 0)
+ r = service_spawn(s,
+ s->control_command,
+ true,
+ false,
+ !s->permissions_start_only,
+ !s->root_directory_start_only,
+ s->control_command_id == SERVICE_EXEC_START_PRE ||
+ s->control_command_id == SERVICE_EXEC_STOP_POST,
+ false,
+ true,
+ &s->control_pid);
+ if (r < 0)
goto fail;
return;
@@ -2310,15 +2327,17 @@ static void service_run_next_main(Service *s) {
s->main_command = s->main_command->command_next;
service_unwatch_main_pid(s);
- if ((r = service_spawn(s,
- s->main_command,
- false,
- true,
- true,
- true,
- true,
- s->notify_access != NOTIFY_NONE,
- &pid)) < 0)
+ r = service_spawn(s,
+ s->main_command,
+ false,
+ true,
+ true,
+ true,
+ true,
+ s->notify_access != NOTIFY_NONE,
+ false,
+ &pid);
+ if (r < 0)
goto fail;
service_set_main_pid(s, pid);
@@ -3644,8 +3663,8 @@ static int service_kill(Unit *u, KillWho who, KillMode mode, int signo, DBusErro
r = q;
goto finish;
}
-
- if ((q = cgroup_bonding_kill_list(UNIT(s)->cgroup_bondings, signo, false, pid_set)) < 0)
+ q = cgroup_bonding_kill_list(UNIT(s)->cgroup_bondings, signo, false, pid_set, NULL);
+ if (q < 0)
if (q != -EAGAIN && q != -ESRCH && q != -ENOENT)
r = q;
}
diff --git a/src/core/socket.c b/src/core/socket.c
index 5b24b34..87d6d86 100644
--- a/src/core/socket.c
+++ b/src/core/socket.c
@@ -1150,6 +1150,7 @@ static int socket_spawn(Socket *s, ExecCommand *c, pid_t *_pid) {
UNIT(s)->manager->confirm_spawn,
UNIT(s)->cgroup_bondings,
UNIT(s)->cgroup_attributes,
+ NULL,
&pid);
strv_free(argv);
@@ -1240,7 +1241,8 @@ static void socket_enter_signal(Socket *s, SocketState state, SocketResult f) {
if ((r = set_put(pid_set, LONG_TO_PTR(s->control_pid))) < 0)
goto fail;
- if ((r = cgroup_bonding_kill_list(UNIT(s)->cgroup_bondings, sig, true, pid_set)) < 0) {
+ r = cgroup_bonding_kill_list(UNIT(s)->cgroup_bondings, sig, true, pid_set, NULL);
+ if (r < 0) {
if (r != -EAGAIN && r != -ESRCH && r != -ENOENT)
log_warning("Failed to kill control group: %s", strerror(-r));
} else if (r > 0)
@@ -2127,7 +2129,8 @@ static int socket_kill(Unit *u, KillWho who, KillMode mode, int signo, DBusError
goto finish;
}
- if ((q = cgroup_bonding_kill_list(UNIT(s)->cgroup_bondings, signo, false, pid_set)) < 0)
+ q = cgroup_bonding_kill_list(UNIT(s)->cgroup_bondings, signo, false, pid_set, NULL);
+ if (q < 0)
if (q != -EAGAIN && q != -ESRCH && q != -ENOENT)
r = q;
}
diff --git a/src/core/swap.c b/src/core/swap.c
index 9c72732..2d39b4c 100644
--- a/src/core/swap.c
+++ b/src/core/swap.c
@@ -621,6 +621,7 @@ static int swap_spawn(Swap *s, ExecCommand *c, pid_t *_pid) {
UNIT(s)->manager->confirm_spawn,
UNIT(s)->cgroup_bondings,
UNIT(s)->cgroup_attributes,
+ NULL,
&pid)) < 0)
goto fail;
@@ -690,7 +691,8 @@ static void swap_enter_signal(Swap *s, SwapState state, SwapResult f) {
if ((r = set_put(pid_set, LONG_TO_PTR(s->control_pid))) < 0)
goto fail;
- if ((r = cgroup_bonding_kill_list(UNIT(s)->cgroup_bondings, sig, true, pid_set)) < 0) {
+ r = cgroup_bonding_kill_list(UNIT(s)->cgroup_bondings, sig, true, pid_set, NULL);
+ if (r < 0) {
if (r != -EAGAIN && r != -ESRCH && r != -ENOENT)
log_warning("Failed to kill control group: %s", strerror(-r));
} else if (r > 0)
@@ -1321,7 +1323,8 @@ static int swap_kill(Unit *u, KillWho who, KillMode mode, int signo, DBusError *
goto finish;
}
- if ((q = cgroup_bonding_kill_list(UNIT(s)->cgroup_bondings, signo, false, pid_set)) < 0)
+ q = cgroup_bonding_kill_list(UNIT(s)->cgroup_bondings, signo, false, pid_set, NULL);
+ if (q < 0)
if (q != -EAGAIN && q != -ESRCH && q != -ENOENT)
r = q;
}