shaba/systemd-stable
1
1
Fork 0
mirror of https://github.com/systemd/systemd-stable.git synced 2025-03-12 08:58:20 +03:00
Code

cgroup-util: allow cg_read_pid() to skip unmapped (zero) pids

Browse Source 
(cherry picked from commit 41219b4e9a71e0936ce1543bf9a3e16321f8f45c)
This commit is contained in:
Timo Rothenpieler 2024-04-28 16:27:06 +02:00 committed by Luca Boccassi
parent 5810c25792
commit 8e57759d6d
7 changed files with 48 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

47
src/basic/cgroup-util.c
View File

@ -62,7 +62,7 @@ int cg_enumerate_processes(const char *controller, const char *path, FILE **ret)
return cg_enumerate_items(controller, path, ret, "cgroup.procs");
}
int cg_read_pid(FILE *f, pid_t *ret) {
int cg_read_pid(FILE *f, pid_t *ret, CGroupFlags flags) {
unsigned long ul;
/* Note that the cgroup.procs might contain duplicates! See cgroups.txt for details. */
@ -70,27 +70,33 @@ int cg_read_pid(FILE *f, pid_t *ret) {
assert(f);
assert(ret);
errno = 0;
if (fscanf(f, "%lu", &ul) != 1) {
for (;;) {
errno = 0;
if (fscanf(f, "%lu", &ul) != 1) {
if (feof(f)) {
*ret = 0;
return 0;
if (feof(f)) {
*ret = 0;
return 0;
}
return errno_or_else(EIO);
}
return errno_or_else(EIO);
if (ul > PID_T_MAX)
return -EIO;
/* In some circumstances (e.g. WSL), cgroups might contain unmappable PIDs from other
* contexts. These show up as zeros, and depending on the caller, can either be plain
* skipped over, or returned as-is. */
if (ul == 0 && !FLAGS_SET(flags, CGROUP_DONT_SKIP_UNMAPPED))
continue;
*ret = (pid_t) ul;
return 1;
}
if (ul <= 0)
return -EIO;
if (ul > PID_T_MAX)
return -EIO;
*ret = (pid_t) ul;
return 1;
}
int cg_read_pidref(FILE *f, PidRef *ret) {
int cg_read_pidref(FILE *f, PidRef *ret, CGroupFlags flags) {
int r;
assert(f);
@ -99,7 +105,7 @@ int cg_read_pidref(FILE *f, PidRef *ret) {
for (;;) {
pid_t pid;
r = cg_read_pid(f, &pid);
r = cg_read_pid(f, &pid, flags);
if (r < 0)
return r;
if (r == 0) {
@ -107,6 +113,9 @@ int cg_read_pidref(FILE *f, PidRef *ret) {
return 0;
}
if (pid == 0)
return -EREMOTE;
r = pidref_set_pid(ret, pid);
if (r >= 0)
return 1;
@ -322,7 +331,7 @@ static int cg_kill_items(
for (;;) {
_cleanup_(pidref_done) PidRef pidref = PIDREF_NULL;
r = cg_read_pidref(f, &pidref);
r = cg_read_pidref(f, &pidref, /* flags = */ 0);
if (r < 0)
return RET_GATHER(ret, r);
if (r == 0)
@ -917,7 +926,7 @@ int cg_is_empty(const char *controller, const char *path) {
if (r < 0)
return r;
r = cg_read_pid(f, &pid);
r = cg_read_pid(f, &pid, CGROUP_DONT_SKIP_UNMAPPED);
if (r < 0)
return r;

17
src/basic/cgroup-util.h
View File

@ -180,20 +180,21 @@ typedef enum CGroupUnified {
* generate paths with multiple adjacent / removed.
*/
typedef enum CGroupFlags {
CGROUP_SIGCONT = 1 << 0,
CGROUP_IGNORE_SELF = 1 << 1,
CGROUP_REMOVE = 1 << 2,
CGROUP_DONT_SKIP_UNMAPPED = 1 << 3,
} CGroupFlags;
int cg_enumerate_processes(const char *controller, const char *path, FILE **ret);
int cg_read_pid(FILE *f, pid_t *ret);
int cg_read_pidref(FILE *f, PidRef *ret);
int cg_read_pid(FILE *f, pid_t *ret, CGroupFlags flags);
int cg_read_pidref(FILE *f, PidRef *ret, CGroupFlags flags);
int cg_read_event(const char *controller, const char *path, const char *event, char **ret);
int cg_enumerate_subgroups(const char *controller, const char *path, DIR **ret);
int cg_read_subgroup(DIR *d, char **ret);
typedef enum CGroupFlags {
CGROUP_SIGCONT = 1 << 0,
CGROUP_IGNORE_SELF = 1 << 1,
CGROUP_REMOVE = 1 << 2,
} CGroupFlags;
typedef int (*cg_kill_log_func_t)(const PidRef *pid, int sig, void *userdata);
int cg_kill(const char *path, int sig, CGroupFlags flags, Set *s, cg_kill_log_func_t kill_log, void *userdata);

2
src/cgtop/cgtop.c
View File

@ -207,7 +207,7 @@ static int process(
return r;
g->n_tasks = 0;
while (cg_read_pid(f, &pid) > 0) {
while (cg_read_pid(f, &pid, CGROUP_DONT_SKIP_UNMAPPED) > 0) {
if (arg_count == COUNT_USERSPACE_PROCESSES && pid_is_kernel_thread(pid) > 0)
continue;

6
src/core/cgroup.c
View File

@ -3181,7 +3181,9 @@ int unit_search_main_pid(Unit *u, PidRef *ret) {
for (;;) {
_cleanup_(pidref_done) PidRef npidref = PIDREF_NULL;
r = cg_read_pidref(f, &npidref);
/* cg_read_pidref() will return an error on unmapped PIDs.
* We can't reasonably deal with units that contain those. */
r = cg_read_pidref(f, &npidref, CGROUP_DONT_SKIP_UNMAPPED);
if (r < 0)
return r;
if (r == 0)
@ -3223,7 +3225,7 @@ static int unit_watch_pids_in_path(Unit *u, const char *path) {
for (;;) {
_cleanup_(pidref_done) PidRef pid = PIDREF_NULL;
r = cg_read_pidref(f, &pid);
r = cg_read_pidref(f, &pid, /* flags = */ 0);
if (r == 0)
break;
if (r < 0) {

2
src/core/dbus-unit.c
View File

@ -1299,7 +1299,7 @@ static int append_cgroup(sd_bus_message *reply, const char *p, Set *pids) {
* 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);
r = cg_read_pidref(f, &pidref, /* flags = */ 0);
if (IN_SET(r, 0, -EOPNOTSUPP))
break;
if (r < 0)

5
src/shared/cgroup-setup.c
View File

@ -597,7 +597,10 @@ int cg_migrate(
return ret;
}
while ((r = cg_read_pid(f, &pid)) > 0) {
while ((r = cg_read_pid(f, &pid, flags)) > 0) {
/* Throw an error if unmappable PIDs are in output, we can't migrate those. */
if (pid == 0)
return -EREMOTE;
/* This might do weird stuff if we aren't a
* single-threaded program. However, we

2
src/shared/cgroup-show.c
View File

@ -108,7 +108,7 @@ static int show_cgroup_one_by_path(
* 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);
r = cg_read_pid(f, &pid, /* flags = */ 0);
if (IN_SET(r, 0, -EOPNOTSUPP))
break;
if (r < 0)