Adding upstream version 255.4.upstream/255.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

2 files changed, 1119 insertions, 0 deletions

diff --git a/src/cgtop/cgtop.c b/src/cgtop/cgtop.c
new file mode 100644
index 0000000..ca51455
--- /dev/null
+++ b/src/cgtop/cgtop.c
@@ -0,0 +1,1110 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <getopt.h>
+#include <signal.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "sd-bus.h"
+
+#include "alloc-util.h"
+#include "build.h"
+#include "bus-error.h"
+#include "bus-util.h"
+#include "cgroup-show.h"
+#include "cgroup-util.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "hashmap.h"
+#include "main-func.h"
+#include "missing_sched.h"
+#include "parse-argument.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "pretty-print.h"
+#include "process-util.h"
+#include "procfs-util.h"
+#include "sort-util.h"
+#include "stdio-util.h"
+#include "strv.h"
+#include "terminal-util.h"
+#include "unit-name.h"
+#include "virt.h"
+
+typedef struct Group {
+        char *path;
+
+        bool n_tasks_valid;
+        bool cpu_valid;
+        bool memory_valid;
+        bool io_valid;
+
+        uint64_t n_tasks;
+
+        unsigned cpu_iteration;
+        nsec_t cpu_usage;
+        nsec_t cpu_timestamp;
+        double cpu_fraction;
+
+        uint64_t memory;
+
+        unsigned io_iteration;
+        uint64_t io_input, io_output;
+        nsec_t io_timestamp;
+        uint64_t io_input_bps, io_output_bps;
+} Group;
+
+/* Counted objects, enum order matters */
+typedef enum PidsCount {
+        COUNT_USERSPACE_PROCESSES,      /* least */
+        COUNT_ALL_PROCESSES,
+        COUNT_PIDS,                     /* most, requires pids controller */
+} PidsCount;
+
+static unsigned arg_depth = 3;
+static unsigned arg_iterations = UINT_MAX;
+static bool arg_batch = false;
+static bool arg_raw = false;
+static usec_t arg_delay = 1*USEC_PER_SEC;
+static char* arg_machine = NULL;
+static char* arg_root = NULL;
+static bool arg_recursive = true;
+static bool arg_recursive_unset = false;
+
+static PidsCount arg_count = COUNT_PIDS;
+
+static enum {
+        ORDER_PATH,
+        ORDER_TASKS,
+        ORDER_CPU,
+        ORDER_MEMORY,
+        ORDER_IO,
+} arg_order = ORDER_CPU;
+
+static enum {
+        CPU_PERCENT,
+        CPU_TIME,
+} arg_cpu_type = CPU_PERCENT;
+
+static Group *group_free(Group *g) {
+        if (!g)
+                return NULL;
+
+        free(g->path);
+        return mfree(g);
+}
+
+DEFINE_PRIVATE_HASH_OPS_WITH_VALUE_DESTRUCTOR(group_hash_ops, char, path_hash_func, path_compare, Group, group_free);
+
+static const char *maybe_format_timespan(char *buf, size_t l, usec_t t, usec_t accuracy) {
+        if (arg_raw) {
+               (void) snprintf(buf, l, USEC_FMT, t);
+               return buf;
+        }
+        return format_timespan(buf, l, t, accuracy);
+}
+
+#define BUFSIZE1 CONST_MAX(FORMAT_TIMESPAN_MAX, DECIMAL_STR_MAX(usec_t))
+#define MAYBE_FORMAT_TIMESPAN(t, accuracy) \
+        maybe_format_timespan((char[BUFSIZE1]){}, BUFSIZE1, t, accuracy)
+
+static const char *maybe_format_bytes(char *buf, size_t l, bool is_valid, uint64_t t) {
+        if (!is_valid)
+                return "-";
+        if (arg_raw) {
+                (void) snprintf(buf, l, "%" PRIu64, t);
+                return buf;
+        }
+        return format_bytes(buf, l, t);
+}
+
+#define BUFSIZE2 CONST_MAX(FORMAT_BYTES_MAX, DECIMAL_STR_MAX(uint64_t))
+#define MAYBE_FORMAT_BYTES(is_valid, t) \
+        maybe_format_bytes((char[BUFSIZE2]){}, BUFSIZE2, is_valid, t)
+
+static bool is_root_cgroup(const char *path) {
+
+        /* Returns true if the specified path belongs to the root cgroup. The root cgroup is special on cgroup v2 as it
+         * carries only very few attributes in order not to export multiple truth about system state as most
+         * information is available elsewhere in /proc anyway. We need to be able to deal with that, and need to get
+         * our data from different sources in that case.
+         *
+         * There's one extra complication in all of this, though 😣: if the path to the cgroup indicates we are in the
+         * root cgroup this might actually not be the case, because cgroup namespacing might be in effect
+         * (CLONE_NEWCGROUP). Since there's no nice way to distinguish a real cgroup root from a fake namespaced one we
+         * do an explicit container check here, under the assumption that CLONE_NEWCGROUP is generally used when
+         * container managers are used too.
+         *
+         * Note that checking for a container environment is kinda ugly, since in theory people could use cgtop from
+         * inside a container where cgroup namespacing is turned off to watch the host system. However, that's mostly a
+         * theoretic use case, and if people actually try all they'll lose is accounting for the top-level cgroup. Which
+         * isn't too bad. */
+
+        if (detect_container() > 0)
+                return false;
+
+        return empty_or_root(path);
+}
+
+static int process(
+                const char *controller,
+                const char *path,
+                Hashmap *a,
+                Hashmap *b,
+                unsigned iteration,
+                Group **ret) {
+
+        Group *g;
+        int r, all_unified;
+
+        assert(controller);
+        assert(path);
+        assert(a);
+
+        all_unified = cg_all_unified();
+        if (all_unified < 0)
+                return all_unified;
+
+        g = hashmap_get(a, path);
+        if (!g) {
+                g = hashmap_get(b, path);
+                if (!g) {
+                        g = new0(Group, 1);
+                        if (!g)
+                                return -ENOMEM;
+
+                        g->path = strdup(path);
+                        if (!g->path) {
+                                group_free(g);
+                                return -ENOMEM;
+                        }
+
+                        r = hashmap_put(a, g->path, g);
+                        if (r < 0) {
+                                group_free(g);
+                                return r;
+                        }
+                } else {
+                        r = hashmap_move_one(a, b, path);
+                        if (r < 0)
+                                return r;
+
+                        g->cpu_valid = g->memory_valid = g->io_valid = g->n_tasks_valid = false;
+                }
+        }
+
+        if (streq(controller, SYSTEMD_CGROUP_CONTROLLER) &&
+            IN_SET(arg_count, COUNT_ALL_PROCESSES, COUNT_USERSPACE_PROCESSES)) {
+                _cleanup_fclose_ FILE *f = NULL;
+                pid_t pid;
+
+                r = cg_enumerate_processes(controller, path, &f);
+                if (r == -ENOENT)
+                        return 0;
+                if (r < 0)
+                        return r;
+
+                g->n_tasks = 0;
+                while (cg_read_pid(f, &pid) > 0) {
+
+                        if (arg_count == COUNT_USERSPACE_PROCESSES && pid_is_kernel_thread(pid) > 0)
+                                continue;
+
+                        g->n_tasks++;
+                }
+
+                if (g->n_tasks > 0)
+                        g->n_tasks_valid = true;
+
+        } else if (streq(controller, "pids") && arg_count == COUNT_PIDS) {
+
+                if (is_root_cgroup(path)) {
+                        r = procfs_tasks_get_current(&g->n_tasks);
+                        if (r < 0)
+                                return r;
+                } else {
+                        _cleanup_free_ char *p = NULL, *v = NULL;
+
+                        r = cg_get_path(controller, path, "pids.current", &p);
+                        if (r < 0)
+                                return r;
+
+                        r = read_one_line_file(p, &v);
+                        if (r == -ENOENT)
+                                return 0;
+                        if (r < 0)
+                                return r;
+
+                        r = safe_atou64(v, &g->n_tasks);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (g->n_tasks > 0)
+                        g->n_tasks_valid = true;
+
+        } else if (streq(controller, "memory")) {
+
+                if (is_root_cgroup(path)) {
+                        r = procfs_memory_get_used(&g->memory);
+                        if (r < 0)
+                                return r;
+                } else {
+                        _cleanup_free_ char *p = NULL, *v = NULL;
+
+                        if (all_unified)
+                                r = cg_get_path(controller, path, "memory.current", &p);
+                        else
+                                r = cg_get_path(controller, path, "memory.usage_in_bytes", &p);
+                        if (r < 0)
+                                return r;
+
+                        r = read_one_line_file(p, &v);
+                        if (r == -ENOENT)
+                                return 0;
+                        if (r < 0)
+                                return r;
+
+                        r = safe_atou64(v, &g->memory);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (g->memory > 0)
+                        g->memory_valid = true;
+
+        } else if ((streq(controller, "io") && all_unified) ||
+                   (streq(controller, "blkio") && !all_unified)) {
+                _cleanup_fclose_ FILE *f = NULL;
+                _cleanup_free_ char *p = NULL;
+                uint64_t wr = 0, rd = 0;
+                nsec_t timestamp;
+
+                r = cg_get_path(controller, path, all_unified ? "io.stat" : "blkio.io_service_bytes", &p);
+                if (r < 0)
+                        return r;
+
+                f = fopen(p, "re");
+                if (!f) {
+                        if (errno == ENOENT)
+                                return 0;
+                        return -errno;
+                }
+
+                for (;;) {
+                        _cleanup_free_ char *line = NULL;
+                        uint64_t k, *q;
+                        char *l;
+
+                        r = read_stripped_line(f, LONG_LINE_MAX, &line);
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                break;
+
+                        /* Skip the device */
+                        l = line + strcspn(line, WHITESPACE);
+                        l += strspn(l, WHITESPACE);
+
+                        if (all_unified) {
+                                while (!isempty(l)) {
+                                        if (sscanf(l, "rbytes=%" SCNu64, &k) == 1)
+                                                rd += k;
+                                        else if (sscanf(l, "wbytes=%" SCNu64, &k) == 1)
+                                                wr += k;
+
+                                        l += strcspn(l, WHITESPACE);
+                                        l += strspn(l, WHITESPACE);
+                                }
+                        } else {
+                                if (first_word(l, "Read")) {
+                                        l += 4;
+                                        q = &rd;
+                                } else if (first_word(l, "Write")) {
+                                        l += 5;
+                                        q = &wr;
+                                } else
+                                        continue;
+
+                                l += strspn(l, WHITESPACE);
+                                r = safe_atou64(l, &k);
+                                if (r < 0)
+                                        continue;
+
+                                *q += k;
+                        }
+                }
+
+                timestamp = now_nsec(CLOCK_MONOTONIC);
+
+                if (g->io_iteration == iteration - 1) {
+                        uint64_t x, yr, yw;
+
+                        x = (uint64_t) (timestamp - g->io_timestamp);
+                        if (x < 1)
+                                x = 1;
+
+                        if (rd > g->io_input)
+                                yr = rd - g->io_input;
+                        else
+                                yr = 0;
+
+                        if (wr > g->io_output)
+                                yw = wr - g->io_output;
+                        else
+                                yw = 0;
+
+                        if (yr > 0 || yw > 0) {
+                                g->io_input_bps = (yr * 1000000000ULL) / x;
+                                g->io_output_bps = (yw * 1000000000ULL) / x;
+                                g->io_valid = true;
+                        }
+                }
+
+                g->io_input = rd;
+                g->io_output = wr;
+                g->io_timestamp = timestamp;
+                g->io_iteration = iteration;
+        } else if (STR_IN_SET(controller, "cpu", "cpuacct") || cpu_accounting_is_cheap()) {
+                _cleanup_free_ char *p = NULL, *v = NULL;
+                uint64_t new_usage;
+                nsec_t timestamp;
+
+                if (is_root_cgroup(path)) {
+                        r = procfs_cpu_get_usage(&new_usage);
+                        if (r < 0)
+                                return r;
+                } else if (all_unified) {
+                        _cleanup_free_ char *val = NULL;
+
+                        if (!streq(controller, "cpu"))
+                                return 0;
+
+                        r = cg_get_keyed_attribute("cpu", path, "cpu.stat", STRV_MAKE("usage_usec"), &val);
+                        if (IN_SET(r, -ENOENT, -ENXIO))
+                                return 0;
+                        if (r < 0)
+                                return r;
+
+                        r = safe_atou64(val, &new_usage);
+                        if (r < 0)
+                                return r;
+
+                        new_usage *= NSEC_PER_USEC;
+                } else {
+                        if (!streq(controller, "cpuacct"))
+                                return 0;
+
+                        r = cg_get_path(controller, path, "cpuacct.usage", &p);
+                        if (r < 0)
+                                return r;
+
+                        r = read_one_line_file(p, &v);
+                        if (r == -ENOENT)
+                                return 0;
+                        if (r < 0)
+                                return r;
+
+                        r = safe_atou64(v, &new_usage);
+                        if (r < 0)
+                                return r;
+                }
+
+                timestamp = now_nsec(CLOCK_MONOTONIC);
+
+                if (g->cpu_iteration == iteration - 1 &&
+                    (nsec_t) new_usage > g->cpu_usage) {
+
+                        nsec_t x, y;
+
+                        x = timestamp - g->cpu_timestamp;
+                        if (x < 1)
+                                x = 1;
+
+                        y = (nsec_t) new_usage - g->cpu_usage;
+                        g->cpu_fraction = (double) y / (double) x;
+                        g->cpu_valid = true;
+                }
+
+                g->cpu_usage = (nsec_t) new_usage;
+                g->cpu_timestamp = timestamp;
+                g->cpu_iteration = iteration;
+
+        }
+
+        if (ret)
+                *ret = g;
+
+        return 0;
+}
+
+static int refresh_one(
+                const char *controller,
+                const char *path,
+                Hashmap *a,
+                Hashmap *b,
+                unsigned iteration,
+                unsigned depth,
+                Group **ret) {
+
+        _cleanup_closedir_ DIR *d = NULL;
+        Group *ours = NULL;
+        int r;
+
+        assert(controller);
+        assert(path);
+        assert(a);
+
+        if (depth > arg_depth)
+                return 0;
+
+        r = process(controller, path, a, b, iteration, &ours);
+        if (r < 0)
+                return r;
+
+        r = cg_enumerate_subgroups(controller, path, &d);
+        if (r == -ENOENT)
+                return 0;
+        if (r < 0)
+                return r;
+
+        for (;;) {
+                _cleanup_free_ char *fn = NULL, *p = NULL;
+                Group *child = NULL;
+
+                r = cg_read_subgroup(d, &fn);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        break;
+
+                p = path_join(path, fn);
+                if (!p)
+                        return -ENOMEM;
+
+                path_simplify(p);
+
+                r = refresh_one(controller, p, a, b, iteration, depth + 1, &child);
+                if (r < 0)
+                        return r;
+
+                if (arg_recursive &&
+                    IN_SET(arg_count, COUNT_ALL_PROCESSES, COUNT_USERSPACE_PROCESSES) &&
+                    child &&
+                    child->n_tasks_valid &&
+                    streq(controller, SYSTEMD_CGROUP_CONTROLLER)) {
+
+                        /* Recursively sum up processes */
+
+                        if (ours->n_tasks_valid)
+                                ours->n_tasks += child->n_tasks;
+                        else {
+                                ours->n_tasks = child->n_tasks;
+                                ours->n_tasks_valid = true;
+                        }
+                }
+        }
+
+        if (ret)
+                *ret = ours;
+
+        return 1;
+}
+
+static int refresh(const char *root, Hashmap *a, Hashmap *b, unsigned iteration) {
+        int r;
+
+        FOREACH_STRING(c, SYSTEMD_CGROUP_CONTROLLER, "cpu", "cpuacct", "memory", "io", "blkio", "pids") {
+                r = refresh_one(c, root, a, b, iteration, 0, NULL);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+static int group_compare(Group * const *a, Group * const *b) {
+        const Group *x = *a, *y = *b;
+        int r;
+
+        if (arg_order != ORDER_TASKS || arg_recursive) {
+                /* Let's make sure that the parent is always before
+                 * the child. Except when ordering by tasks and
+                 * recursive summing is off, since that is actually
+                 * not accumulative for all children. */
+
+                if (path_startswith(empty_to_root(y->path), empty_to_root(x->path)))
+                        return -1;
+                if (path_startswith(empty_to_root(x->path), empty_to_root(y->path)))
+                        return 1;
+        }
+
+        switch (arg_order) {
+
+        case ORDER_PATH:
+                break;
+
+        case ORDER_CPU:
+                if (arg_cpu_type == CPU_PERCENT) {
+                        if (x->cpu_valid && y->cpu_valid) {
+                                r = CMP(y->cpu_fraction, x->cpu_fraction);
+                                if (r != 0)
+                                        return r;
+                        } else if (x->cpu_valid)
+                                return -1;
+                        else if (y->cpu_valid)
+                                return 1;
+                } else {
+                        r = CMP(y->cpu_usage, x->cpu_usage);
+                        if (r != 0)
+                                return r;
+                }
+
+                break;
+
+        case ORDER_TASKS:
+                if (x->n_tasks_valid && y->n_tasks_valid) {
+                        r = CMP(y->n_tasks, x->n_tasks);
+                        if (r != 0)
+                                return r;
+                } else if (x->n_tasks_valid)
+                        return -1;
+                else if (y->n_tasks_valid)
+                        return 1;
+
+                break;
+
+        case ORDER_MEMORY:
+                if (x->memory_valid && y->memory_valid) {
+                        r = CMP(y->memory, x->memory);
+                        if (r != 0)
+                                return r;
+                } else if (x->memory_valid)
+                        return -1;
+                else if (y->memory_valid)
+                        return 1;
+
+                break;
+
+        case ORDER_IO:
+                if (x->io_valid && y->io_valid) {
+                        r = CMP(y->io_input_bps + y->io_output_bps, x->io_input_bps + x->io_output_bps);
+                        if (r != 0)
+                                return r;
+                } else if (x->io_valid)
+                        return -1;
+                else if (y->io_valid)
+                        return 1;
+        }
+
+        return path_compare(x->path, y->path);
+}
+
+static void display(Hashmap *a) {
+        Group *g;
+        Group **array;
+        signed path_columns;
+        unsigned rows, n = 0, maxtcpu = 0, maxtpath = 3; /* 3 for ellipsize() to work properly */
+
+        assert(a);
+
+        if (!terminal_is_dumb())
+                fputs(ANSI_HOME_CLEAR, stdout);
+
+        array = newa(Group*, hashmap_size(a));
+
+        HASHMAP_FOREACH(g, a)
+                if (g->n_tasks_valid || g->cpu_valid || g->memory_valid || g->io_valid)
+                        array[n++] = g;
+
+        typesafe_qsort(array, n, group_compare);
+
+        /* Find the longest names in one run */
+        for (unsigned j = 0; j < n; j++) {
+                maxtcpu = MAX(maxtcpu,
+                              strlen(MAYBE_FORMAT_TIMESPAN((usec_t) (array[j]->cpu_usage / NSEC_PER_USEC), 0)));
+                maxtpath = MAX(maxtpath,
+                               strlen(array[j]->path));
+        }
+
+        rows = lines();
+        if (rows <= 10)
+                rows = 10;
+
+        if (on_tty()) {
+                const char *on, *off;
+                int cpu_len = arg_cpu_type == CPU_PERCENT ? 6 : maxtcpu;
+
+                path_columns = columns() - 36 - cpu_len;
+                if (path_columns < 10)
+                        path_columns = 10;
+
+                on = ansi_highlight_underline();
+                off = ansi_underline();
+
+                printf("%s%s%-*s%s %s%7s%s %s%*s%s %s%8s%s %s%8s%s %s%8s%s%s\n",
+                       ansi_underline(),
+                       arg_order == ORDER_PATH ? on : "", path_columns, "CGroup",
+                       arg_order == ORDER_PATH ? off : "",
+                       arg_order == ORDER_TASKS ? on : "",
+                       arg_count == COUNT_PIDS ? "Tasks" : arg_count == COUNT_USERSPACE_PROCESSES ? "Procs" : "Proc+",
+                       arg_order == ORDER_TASKS ? off : "",
+                       arg_order == ORDER_CPU ? on : "",
+                       cpu_len,
+                       arg_cpu_type == CPU_PERCENT ? "%CPU" : "CPU Time",
+                       arg_order == ORDER_CPU ? off : "",
+                       arg_order == ORDER_MEMORY ? on : "", "Memory",
+                       arg_order == ORDER_MEMORY ? off : "",
+                       arg_order == ORDER_IO ? on : "", "Input/s",
+                       arg_order == ORDER_IO ? off : "",
+                       arg_order == ORDER_IO ? on : "", "Output/s",
+                       arg_order == ORDER_IO ? off : "",
+                       ansi_normal());
+        } else
+                path_columns = maxtpath;
+
+        for (unsigned j = 0; j < n; j++) {
+                _cleanup_free_ char *ellipsized = NULL;
+                const char *path;
+
+                if (on_tty() && j + 6 > rows)
+                        break;
+
+                g = array[j];
+
+                path = empty_to_root(g->path);
+                ellipsized = ellipsize(path, path_columns, 33);
+                printf("%-*s", path_columns, ellipsized ?: path);
+
+                if (g->n_tasks_valid)
+                        printf(" %7" PRIu64, g->n_tasks);
+                else
+                        fputs("       -", stdout);
+
+                if (arg_cpu_type == CPU_PERCENT) {
+                        if (g->cpu_valid)
+                                printf(" %6.1f", g->cpu_fraction*100);
+                        else
+                                fputs("      -", stdout);
+                } else
+                        printf(" %*s",
+                               (int) maxtcpu,
+                               MAYBE_FORMAT_TIMESPAN((usec_t) (g->cpu_usage / NSEC_PER_USEC), 0));
+
+                printf(" %8s", MAYBE_FORMAT_BYTES(g->memory_valid, g->memory));
+                printf(" %8s", MAYBE_FORMAT_BYTES(g->io_valid, g->io_input_bps));
+                printf(" %8s", MAYBE_FORMAT_BYTES(g->io_valid, g->io_output_bps));
+
+                putchar('\n');
+        }
+}
+
+static int help(void) {
+        _cleanup_free_ char *link = NULL;
+        int r;
+
+        r = terminal_urlify_man("systemd-cgtop", "1", &link);
+        if (r < 0)
+                return log_oom();
+
+        printf("%s [OPTIONS...] [CGROUP]\n\n"
+               "Show top control groups by their resource usage.\n\n"
+               "  -h --help           Show this help\n"
+               "     --version        Show package version\n"
+               "  -p --order=path     Order by path\n"
+               "  -t --order=tasks    Order by number of tasks/processes\n"
+               "  -c --order=cpu      Order by CPU load (default)\n"
+               "  -m --order=memory   Order by memory load\n"
+               "  -i --order=io       Order by IO load\n"
+               "  -r --raw            Provide raw (not human-readable) numbers\n"
+               "     --cpu=percentage Show CPU usage as percentage (default)\n"
+               "     --cpu=time       Show CPU usage as time\n"
+               "  -P                  Count userspace processes instead of tasks (excl. kernel)\n"
+               "  -k                  Count all processes instead of tasks (incl. kernel)\n"
+               "     --recursive=BOOL Sum up process count recursively\n"
+               "  -d --delay=DELAY    Delay between updates\n"
+               "  -n --iterations=N   Run for N iterations before exiting\n"
+               "  -1                  Shortcut for --iterations=1\n"
+               "  -b --batch          Run in batch mode, accepting no input\n"
+               "     --depth=DEPTH    Maximum traversal depth (default: %u)\n"
+               "  -M --machine=       Show container\n"
+               "\nSee the %s for details.\n",
+               program_invocation_short_name,
+               arg_depth,
+               link);
+
+        return 0;
+}
+
+static int parse_argv(int argc, char *argv[]) {
+        enum {
+                ARG_VERSION = 0x100,
+                ARG_DEPTH,
+                ARG_CPU_TYPE,
+                ARG_ORDER,
+                ARG_RECURSIVE,
+        };
+
+        static const struct option options[] = {
+                { "help",         no_argument,       NULL, 'h'           },
+                { "version",      no_argument,       NULL, ARG_VERSION   },
+                { "delay",        required_argument, NULL, 'd'           },
+                { "iterations",   required_argument, NULL, 'n'           },
+                { "batch",        no_argument,       NULL, 'b'           },
+                { "raw",          no_argument,       NULL, 'r'           },
+                { "depth",        required_argument, NULL, ARG_DEPTH     },
+                { "cpu",          optional_argument, NULL, ARG_CPU_TYPE  },
+                { "order",        required_argument, NULL, ARG_ORDER     },
+                { "recursive",    required_argument, NULL, ARG_RECURSIVE },
+                { "machine",      required_argument, NULL, 'M'           },
+                {}
+        };
+
+        int c, r;
+
+        assert(argc >= 1);
+        assert(argv);
+
+        while ((c = getopt_long(argc, argv, "hptcmin:brd:kPM:1", options, NULL)) >= 0)
+
+                switch (c) {
+
+                case 'h':
+                        return help();
+
+                case ARG_VERSION:
+                        return version();
+
+                case ARG_CPU_TYPE:
+                        if (optarg) {
+                                if (streq(optarg, "time"))
+                                        arg_cpu_type = CPU_TIME;
+                                else if (streq(optarg, "percentage"))
+                                        arg_cpu_type = CPU_PERCENT;
+                                else
+                                        return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                                               "Unknown argument to --cpu=: %s",
+                                                               optarg);
+                        } else
+                                arg_cpu_type = CPU_TIME;
+
+                        break;
+
+                case ARG_DEPTH:
+                        r = safe_atou(optarg, &arg_depth);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to parse depth parameter '%s': %m", optarg);
+
+                        break;
+
+                case 'd':
+                        r = parse_sec(optarg, &arg_delay);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to parse delay parameter '%s': %m", optarg);
+                        if (arg_delay <= 0)
+                                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                                       "Invalid delay parameter '%s'",
+                                                       optarg);
+
+                        break;
+
+                case 'n':
+                        r = safe_atou(optarg, &arg_iterations);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to parse iterations parameter '%s': %m", optarg);
+
+                        break;
+
+                case '1':
+                        arg_iterations = 1;
+                        break;
+
+                case 'b':
+                        arg_batch = true;
+                        break;
+
+                case 'r':
+                        arg_raw = true;
+                        break;
+
+                case 'p':
+                        arg_order = ORDER_PATH;
+                        break;
+
+                case 't':
+                        arg_order = ORDER_TASKS;
+                        break;
+
+                case 'c':
+                        arg_order = ORDER_CPU;
+                        break;
+
+                case 'm':
+                        arg_order = ORDER_MEMORY;
+                        break;
+
+                case 'i':
+                        arg_order = ORDER_IO;
+                        break;
+
+                case ARG_ORDER:
+                        if (streq(optarg, "path"))
+                                arg_order = ORDER_PATH;
+                        else if (streq(optarg, "tasks"))
+                                arg_order = ORDER_TASKS;
+                        else if (streq(optarg, "cpu"))
+                                arg_order = ORDER_CPU;
+                        else if (streq(optarg, "memory"))
+                                arg_order = ORDER_MEMORY;
+                        else if (streq(optarg, "io"))
+                                arg_order = ORDER_IO;
+                        else
+                                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                                       "Invalid argument to --order=: %s",
+                                                       optarg);
+                        break;
+
+                case 'k':
+                        arg_count = COUNT_ALL_PROCESSES;
+                        break;
+
+                case 'P':
+                        arg_count = COUNT_USERSPACE_PROCESSES;
+                        break;
+
+                case ARG_RECURSIVE:
+                        r = parse_boolean_argument("--recursive=", optarg, &arg_recursive);
+                        if (r < 0)
+                                return r;
+
+                        arg_recursive_unset = !r;
+                        break;
+
+                case 'M':
+                        arg_machine = optarg;
+                        break;
+
+                case '?':
+                        return -EINVAL;
+
+                default:
+                        assert_not_reached();
+                }
+
+        if (optind == argc - 1)
+                arg_root = argv[optind];
+        else if (optind < argc)
+                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "Too many arguments.");
+
+        return 1;
+}
+
+static const char* counting_what(void) {
+        if (arg_count == COUNT_PIDS)
+                return "tasks";
+        else if (arg_count == COUNT_ALL_PROCESSES)
+                return "all processes (incl. kernel)";
+        else
+                return "userspace processes (excl. kernel)";
+}
+
+static int loop(const char *root) {
+        _cleanup_hashmap_free_ Hashmap *a = NULL, *b = NULL;
+        unsigned iteration = 0;
+        usec_t last_refresh = 0;
+        bool immediate_refresh = false;
+        int r;
+
+        a = hashmap_new(&group_hash_ops);
+        b = hashmap_new(&group_hash_ops);
+        if (!a || !b)
+                return log_oom();
+
+        for (;;) {
+                usec_t t;
+                char key;
+
+                t = now(CLOCK_MONOTONIC);
+
+                if (t >= usec_add(last_refresh, arg_delay) || immediate_refresh) {
+
+                        r = refresh(root, a, b, iteration++);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to refresh: %m");
+
+                        hashmap_clear(b);
+                        SWAP_TWO(a, b);
+
+                        last_refresh = t;
+                        immediate_refresh = false;
+                }
+
+                display(b);
+
+                if (arg_iterations && iteration >= arg_iterations)
+                        return 0;
+
+                if (!on_tty()) /* non-TTY: Empty newline as delimiter between polls */
+                        fputs("\n", stdout);
+                fflush(stdout);
+
+                if (arg_batch)
+                        (void) usleep_safe(usec_add(usec_sub_unsigned(last_refresh, t), arg_delay));
+                else {
+                        r = read_one_char(stdin, &key, usec_add(usec_sub_unsigned(last_refresh, t), arg_delay), NULL);
+                        if (r == -ETIMEDOUT)
+                                continue;
+                        if (r < 0)
+                                return log_error_errno(r, "Couldn't read key: %m");
+                }
+
+                if (on_tty()) { /* TTY: Clear any user keystroke */
+                        fputs("\r \r", stdout);
+                        fflush(stdout);
+                }
+
+                if (arg_batch)
+                        continue;
+
+                switch (key) {
+
+                case ' ':
+                        immediate_refresh = true;
+                        break;
+
+                case 'q':
+                        return 0;
+
+                case 'p':
+                        arg_order = ORDER_PATH;
+                        break;
+
+                case 't':
+                        arg_order = ORDER_TASKS;
+                        break;
+
+                case 'c':
+                        arg_order = ORDER_CPU;
+                        break;
+
+                case 'm':
+                        arg_order = ORDER_MEMORY;
+                        break;
+
+                case 'i':
+                        arg_order = ORDER_IO;
+                        break;
+
+                case '%':
+                        arg_cpu_type = arg_cpu_type == CPU_TIME ? CPU_PERCENT : CPU_TIME;
+                        break;
+
+                case 'k':
+                        arg_count = arg_count != COUNT_ALL_PROCESSES ? COUNT_ALL_PROCESSES : COUNT_PIDS;
+                        fprintf(stdout, "\nCounting: %s.", counting_what());
+                        fflush(stdout);
+                        sleep(1);
+                        break;
+
+                case 'P':
+                        arg_count = arg_count != COUNT_USERSPACE_PROCESSES ? COUNT_USERSPACE_PROCESSES : COUNT_PIDS;
+                        fprintf(stdout, "\nCounting: %s.", counting_what());
+                        fflush(stdout);
+                        sleep(1);
+                        break;
+
+                case 'r':
+                        if (arg_count == COUNT_PIDS)
+                                fprintf(stdout, "\n\aCannot toggle recursive counting, not available in task counting mode.");
+                        else {
+                                arg_recursive = !arg_recursive;
+                                fprintf(stdout, "\nRecursive process counting: %s", yes_no(arg_recursive));
+                        }
+                        fflush(stdout);
+                        sleep(1);
+                        break;
+
+                case '+':
+                        arg_delay = usec_add(arg_delay, arg_delay < USEC_PER_SEC ? USEC_PER_MSEC * 250 : USEC_PER_SEC);
+
+                        fprintf(stdout, "\nIncreased delay to %s.", FORMAT_TIMESPAN(arg_delay, 0));
+                        fflush(stdout);
+                        sleep(1);
+                        break;
+
+                case '-':
+                        if (arg_delay <= USEC_PER_MSEC*500)
+                                arg_delay = USEC_PER_MSEC*250;
+                        else
+                                arg_delay = usec_sub_unsigned(arg_delay, arg_delay < USEC_PER_MSEC * 1250 ? USEC_PER_MSEC * 250 : USEC_PER_SEC);
+
+                        fprintf(stdout, "\nDecreased delay to %s.", FORMAT_TIMESPAN(arg_delay, 0));
+                        fflush(stdout);
+                        sleep(1);
+                        break;
+
+                case '?':
+                case 'h':
+
+                        fprintf(stdout,
+                                "\t<%1$sp%2$s> By path; <%1$st%2$s> By tasks/procs; <%1$sc%2$s> By CPU; <%1$sm%2$s> By memory; <%1$si%2$s> By I/O\n"
+                                "\t<%1$s+%2$s> Inc. delay; <%1$s-%2$s> Dec. delay; <%1$s%%%2$s> Toggle time; <%1$sSPACE%2$s> Refresh\n"
+                                "\t<%1$sP%2$s> Toggle count userspace processes; <%1$sk%2$s> Toggle count all processes\n"
+                                "\t<%1$sr%2$s> Count processes recursively; <%1$sq%2$s> Quit",
+                                ansi_highlight(), ansi_normal());
+                        fflush(stdout);
+                        sleep(3);
+                        break;
+
+                default:
+                        if (key < ' ')
+                                fprintf(stdout, "\nUnknown key '\\x%x'. Ignoring.", (unsigned) key);
+                        else
+                                fprintf(stdout, "\nUnknown key '%c'. Ignoring.", key);
+                        fflush(stdout);
+                        sleep(1);
+                        break;
+                }
+        }
+}
+
+static int run(int argc, char *argv[]) {
+        _cleanup_free_ char *root = NULL;
+        CGroupMask mask;
+        int r;
+
+        log_setup();
+
+        r = parse_argv(argc, argv);
+        if (r <= 0)
+                return r;
+
+        r = cg_mask_supported(&mask);
+        if (r < 0)
+                return log_error_errno(r, "Failed to determine supported controllers: %m");
+
+        /* honor user selection unless pids controller is unavailable */
+        PidsCount possible_count = (mask & CGROUP_MASK_PIDS) ? COUNT_PIDS : COUNT_ALL_PROCESSES;
+        arg_count = MIN(possible_count, arg_count);
+
+        if (arg_recursive_unset && arg_count == COUNT_PIDS)
+                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "Non-recursive counting is only supported when counting processes, not tasks. Use -P or -k.");
+
+        r = show_cgroup_get_path_and_warn(arg_machine, arg_root, &root);
+        if (r < 0)
+                return log_error_errno(r, "Failed to get root control group path: %m");
+        log_debug("CGroup path: %s", root);
+
+        signal(SIGWINCH, columns_lines_cache_reset);
+
+        if (arg_iterations == UINT_MAX)
+                arg_iterations = on_tty() ? 0 : 1;
+
+        return loop(root);
+}
+
+DEFINE_MAIN_FUNCTION(run);
diff --git a/src/cgtop/meson.build b/src/cgtop/meson.build
new file mode 100644
index 0000000..afe6a33
--- /dev/null
+++ b/src/cgtop/meson.build
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
+executables += [
+        executable_template + {
+                'name' : 'systemd-cgtop',
+                'public' : true,
+                'sources' : files('cgtop.c'),
+        },
+]