cgls: modernize cgls in preparation for unified cgroup hierarchy work

Fix --machine= handling, don't hardcode long-obsolete container
cgroup paths

Many other clean-ups.

1 files changed, 111 insertions, 99 deletions

diff --git a/src/cgls/cgls.c b/src/cgls/cgls.c
index b8d1d2ccaf..fae9398aa5 100644
--- a/src/cgls/cgls.c
+++ b/src/cgls/cgls.c
@@ -54,7 +54,7 @@ static void help(void) {
                "  -a --all            Show all groups, including empty\n"
                "  -l --full           Do not ellipsize output\n"
                "  -k                  Include kernel threads in output\n"
-               "  -M --machine        Show container\n"
+               "  -M --machine=       Show container\n"
                , program_invocation_short_name);
 }
 
@@ -123,146 +123,158 @@ static int parse_argv(int argc, char *argv[]) {
         return 1;
 }
 
-int main(int argc, char *argv[]) {
-        int r = 0, retval = EXIT_FAILURE;
-        int output_flags;
-        _cleanup_free_ char *root = NULL;
+static int get_cgroup_root(char **ret) {
+        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
         _cleanup_bus_flush_close_unref_ sd_bus *bus = NULL;
+        _cleanup_free_ char *unit = NULL, *path = NULL;
+        const char *m;
+        int r;
+
+        if (!arg_machine) {
+                r = cg_get_root_path(ret);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to get root control group path: %m");
+
+                return 0;
+        }
+
+        m = strjoina("/run/systemd/machines/", arg_machine);
+        r = parse_env_file(m, NEWLINE, "SCOPE", &unit, NULL);
+        if (r < 0)
+                return log_error_errno(r, "Failed to load machine data: %m");
+
+        path = unit_dbus_path_from_name(unit);
+        if (!path)
+                return log_oom();
+
+        r = bus_open_transport(BUS_TRANSPORT_LOCAL, NULL, false, &bus);
+        if (r < 0)
+                return log_error_errno(r, "Failed to create bus connection: %m");
+
+        r = sd_bus_get_property_string(
+                        bus,
+                        "org.freedesktop.systemd1",
+                        path,
+                        unit_dbus_interface_from_name(unit),
+                        "ControlGroup",
+                        &error,
+                        ret);
+        if (r < 0)
+                return log_error_errno(r, "Failed to query unit control group path: %m");
+
+        return 0;
+}
+
+int main(int argc, char *argv[]) {
+        int r, output_flags;
 
         log_parse_environment();
         log_open();
 
         r = parse_argv(argc, argv);
-        if (r < 0)
+        if (r <= 0)
                 goto finish;
-        else if (r == 0) {
-                retval = EXIT_SUCCESS;
-                goto finish;
-        }
 
         if (!arg_no_pager) {
                 r = pager_open(false);
-                if (r > 0) {
-                        if (arg_full == -1)
-                                arg_full = true;
-                }
+                if (r > 0 && arg_full < 0)
+                        arg_full = true;
         }
 
         output_flags =
                 arg_all * OUTPUT_SHOW_ALL |
                 (arg_full > 0) * OUTPUT_FULL_WIDTH;
 
-        r = bus_open_transport(BUS_TRANSPORT_LOCAL, NULL, false, &bus);
-        if (r < 0) {
-                log_error_errno(r, "Failed to create bus connection: %m");
-                goto finish;
-        }
-
         if (optind < argc) {
+                _cleanup_free_ char *root = NULL;
                 int i;
 
+                r = get_cgroup_root(&root);
+                if (r < 0)
+                        goto finish;
+
                 for (i = optind; i < argc; i++) {
                         int q;
 
-                        fprintf(stdout, "%s:\n", argv[i]);
-                        fflush(stdout);
-
-                        if (arg_machine)
-                                root = strjoin("machine/", arg_machine, "/", argv[i], NULL);
-                        else
-                                root = strdup(argv[i]);
-                        if (!root)
-                                return log_oom();
-
-                        q = show_cgroup_by_path(root, NULL, 0,
-                                                arg_kernel_threads, output_flags);
-                        if (q < 0)
-                                r = q;
-                }
+                        if (path_startswith(argv[i], "/sys/fs/cgroup")) {
 
-        } else {
-                _cleanup_free_ char *p;
+                                printf("Directory %s:\n", argv[i]);
+                                fflush(stdout);
 
-                p = get_current_dir_name();
-                if (!p) {
-                        log_error_errno(errno, "Cannot determine current working directory: %m");
-                        goto finish;
-                }
+                                q = show_cgroup_by_path(argv[i], NULL, 0, arg_kernel_threads, output_flags);
+                        } else {
+                                _cleanup_free_ char *c = NULL, *p = NULL, *j = NULL;
+                                const char *controller, *path;
 
-                if (path_startswith(p, "/sys/fs/cgroup") && !arg_machine) {
-                        printf("Working Directory %s:\n", p);
-                        r = show_cgroup_by_path(p, NULL, 0,
-                                                arg_kernel_threads, output_flags);
-                } else {
-                        if (arg_machine) {
-                                char *m;
-                                const char *cgroup;
-                                _cleanup_free_ char *unit = NULL;
-                                _cleanup_free_ char *path = NULL;
-                                _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
-                                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
-
-                                m = strjoina("/run/systemd/machines/", arg_machine);
-                                r = parse_env_file(m, NEWLINE, "SCOPE", &unit, NULL);
+                                r = cg_split_spec(argv[i], &c, &p);
                                 if (r < 0) {
-                                        log_error_errno(r, "Failed to get machine path: %m");
+                                        log_error_errno(r, "Failed to split argument %s: %m", argv[i]);
                                         goto finish;
                                 }
 
-                                path = unit_dbus_path_from_name(unit);
-                                if (!path) {
-                                        log_oom();
-                                        goto finish;
-                                }
+                                controller = c ?: SYSTEMD_CGROUP_CONTROLLER;
+                                if (p) {
+                                        j = strjoin(root, "/", p, NULL);
+                                        if (!j) {
+                                                r = log_oom();
+                                                goto finish;
+                                        }
 
-                                r = sd_bus_get_property(
-                                                bus,
-                                                "org.freedesktop.systemd1",
-                                                path,
-                                                endswith(unit, ".scope") ? "org.freedesktop.systemd1.Scope" : "org.freedesktop.systemd1.Service",
-                                                "ControlGroup",
-                                                &error,
-                                                &reply,
-                                                "s");
+                                        path_kill_slashes(j);
+                                        path = j;
+                                } else
+                                        path = root;
 
-                                if (r < 0) {
-                                        log_error("Failed to query ControlGroup: %s", bus_error_message(&error, -r));
-                                        goto finish;
-                                }
+                                printf("Controller %s; control group %s:\n", controller, path);
+                                fflush(stdout);
 
-                                r = sd_bus_message_read(reply, "s", &cgroup);
-                                if (r < 0) {
-                                        bus_log_parse_error(r);
-                                        goto finish;
-                                }
+                                q = show_cgroup(controller, path, NULL, 0, arg_kernel_threads, output_flags);
+                        }
 
-                                root = strdup(cgroup);
-                                if (!root) {
-                                        log_oom();
-                                        goto finish;
-                                }
+                        if (q < 0)
+                                r = q;
+                }
+
+        } else {
+                bool done = false;
 
-                        } else
-                                r = cg_get_root_path(&root);
-                        if (r < 0) {
-                                log_error_errno(r, "Failed to get %s path: %m",
-                                                arg_machine ? "machine" : "root");
+                if (!arg_machine)  {
+                        _cleanup_free_ char *cwd = NULL;
+
+                        cwd = get_current_dir_name();
+                        if (!cwd) {
+                                r = log_error_errno(errno, "Cannot determine current working directory: %m");
                                 goto finish;
                         }
 
-                        r = show_cgroup(SYSTEMD_CGROUP_CONTROLLER, root, NULL, 0,
-                                        arg_kernel_threads, output_flags);
+                        if (path_startswith(cwd, "/sys/fs/cgroup")) {
+                                printf("Working directory %s:\n", cwd);
+                                fflush(stdout);
+
+                                r = show_cgroup_by_path(cwd, NULL, 0, arg_kernel_threads, output_flags);
+                                done = true;
+                        }
+                }
+
+                if (!done) {
+                        _cleanup_free_ char *root = NULL;
+
+                        r = get_cgroup_root(&root);
+                        if (r < 0)
+                                goto finish;
+
+                        printf("Control group %s:\n", root);
+                        fflush(stdout);
+
+                        r = show_cgroup(SYSTEMD_CGROUP_CONTROLLER, root, NULL, 0, arg_kernel_threads, output_flags);
                 }
         }
 
-        if (r < 0) {
-                log_error_errno(r, "Failed to list cgroup tree %s: %m", root);
-                retval = EXIT_FAILURE;
-        } else
-                retval = EXIT_SUCCESS;
+        if (r < 0)
+                log_error_errno(r, "Failed to list cgroup tree: %m");
 
 finish:
         pager_close();
 
-        return retval;
+        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 }