system/systemd
system/systemd
1
0
Fork 0
mirror of https://github.com/systemd/systemd synced 2024-09-16 06:43:18 +00:00
Code Issues Packages Projects Releases Wiki Activity

dbus-unit: make sure GetProcesses() D-Bus call internally uses pidfd

Browse source 
This way we can be sure to provide an atomic view of the process tree of
a unit.
This commit is contained in:
Lennart Poettering 2023-10-16 23:18:37 +02:00
parent fc87713bed
commit d57d521cae
1 changed files with 21 additions and 15 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

36
src/core/dbus-unit.c
View file

@ -1232,21 +1232,21 @@ static int property_get_cgroup(
return sd_bus_message_append(reply, "s", t);
}
static int append_process(sd_bus_message *reply, const char *p, pid_t pid, Set *pids) {
static int append_process(sd_bus_message *reply, const char *p, PidRef *pid, Set *pids) {
_cleanup_free_ char *buf = NULL, *cmdline = NULL;
int r;
assert(reply);
assert(pid > 0);
assert(pidref_is_set(pid));
r = set_put(pids, PID_TO_PTR(pid));
r = set_put(pids, PID_TO_PTR(pid->pid));
if (IN_SET(r, 0, -EEXIST))
return 0;
if (r < 0)
return r;
if (!p) {
r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &buf);
r = cg_pidref_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &buf);
if (r == -ESRCH)
return 0;
if (r < 0)
@ -1255,7 +1255,7 @@ static int append_process(sd_bus_message *reply, const char *p, pid_t pid, Set *
p = buf;
}
(void) pid_get_cmdline(
(void) pidref_get_cmdline(
pid,
SIZE_MAX,
PROCESS_CMDLINE_COMM_FALLBACK | PROCESS_CMDLINE_QUOTE,
@ -1264,7 +1264,7 @@ static int append_process(sd_bus_message *reply, const char *p, pid_t pid, Set *
return sd_bus_message_append(reply,
"(sus)",
p,
(uint32_t) pid,
(uint32_t) pid->pid,
cmdline);
}
@ -1283,22 +1283,28 @@ static int append_cgroup(sd_bus_message *reply, const char *p, Set *pids) {
return r;
for (;;) {
pid_t pid;
_cleanup_(pidref_done) PidRef pidref = PIDREF_NULL;
/* libvirt / qemu uses threaded mode and cgroup.procs cannot be read at the lower levels.
* From https://docs.kernel.org/admin-guide/cgroup-v2.html#threads,
* “cgroup.procs” in a threaded domain cgroup contains the PIDs of all processes in
* the subtree and is not readable in the subtree proper. */
r = cg_read_pid(f, &pid);
* From https://docs.kernel.org/admin-guide/cgroup-v2.html#threads, “cgroup.procs” in a
* threaded domain cgroup contains the PIDs of all processes in the subtree and is not
* readable in the subtree proper. */
r = cg_read_pidref(f, &pidref);
if (IN_SET(r, 0, -EOPNOTSUPP))
break;
if (r < 0)
return r;
if (pid_is_kernel_thread(pid) > 0)
r = pidref_is_kernel_thread(&pidref);
if (r == -ESRCH) /* gone by now */
continue;
if (r < 0)
log_debug_errno(r, "Failed to determine if " PID_FMT " is a kernel thread, assuming not: %m", pidref.pid);
if (r > 0)
continue;
r = append_process(reply, p, pid, pids);
r = append_process(reply, p, &pidref, pids);
if (r < 0)
return r;
}
@ -1363,14 +1369,14 @@ int bus_unit_method_get_processes(sd_bus_message *message, void *userdata, sd_bu
/* The main and control pids might live outside of the cgroup, hence fetch them separately */
PidRef *pid = unit_main_pid(u);
if (pidref_is_set(pid)) {
r = append_process(reply, NULL, pid->pid, pids);
r = append_process(reply, NULL, pid, pids);
if (r < 0)
return r;
}
pid = unit_control_pid(u);
if (pidref_is_set(pid)) {
r = append_process(reply, NULL, pid->pid, pids);
r = append_process(reply, NULL, pid, pids);
if (r < 0)
return r;
}