systemctl: split up humungous systemctl.c file

This is just some refactoring: shifting around of code, not change in
codeflow.

This splits up the way too huge systemctl.c in multiple more easily
digestable files. It roughly follows the rule that each family of verbs
gets its own .c/.h file pair, and so do all the compat executable names
we support. Plus three extra files for sysv compat (which existed before
already, but I renamed slightly, to get the systemctl- prefix lik
everything else), a -util file with generic stuff everything uses, and a
-logind file with everything that talks directly to logind instead of
PID1.

systemctl is still a bit too complex for my taste, but I think this way
itc omes in a more digestable bits at least.

No change of behaviour, just reshuffling of some code.

1 files changed, 248 insertions, 0 deletions

diff --git a/src/systemctl/systemctl-start-special.c b/src/systemctl/systemctl-start-special.c
new file mode 100644
index 0000000000..46f58ff921
--- /dev/null
+++ b/src/systemctl/systemctl-start-special.c
@@ -0,0 +1,248 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include "bootspec.h"
+#include "bus-error.h"
+#include "bus-locator.h"
+#include "efivars.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "process-util.h"
+#include "reboot-util.h"
+#include "systemctl-logind.h"
+#include "systemctl-start-special.h"
+#include "systemctl-start-unit.h"
+#include "systemctl-trivial-method.h"
+#include "systemctl-util.h"
+#include "systemctl.h"
+
+static int load_kexec_kernel(void) {
+        _cleanup_(boot_config_free) BootConfig config = {};
+        _cleanup_free_ char *kernel = NULL, *initrd = NULL, *options = NULL;
+        const BootEntry *e;
+        pid_t pid;
+        int r;
+
+        if (kexec_loaded()) {
+                log_debug("Kexec kernel already loaded.");
+                return 0;
+        }
+
+        if (access(KEXEC, X_OK) < 0)
+                return log_error_errno(errno, KEXEC" is not available: %m");
+
+        r = boot_entries_load_config_auto(NULL, NULL, &config);
+        if (r == -ENOKEY)
+                /* The call doesn't log about ENOKEY, let's do so here. */
+                return log_error_errno(r,
+                                       "No kexec kernel loaded and autodetection failed.\n%s",
+                                       is_efi_boot()
+                                       ? "Cannot automatically load kernel: ESP partition mount point not found."
+                                       : "Automatic loading works only on systems booted with EFI.");
+        if (r < 0)
+                return r;
+
+        e = boot_config_default_entry(&config);
+        if (!e)
+                return log_error_errno(SYNTHETIC_ERRNO(ENOENT),
+                                       "No boot loader entry suitable as default, refusing to guess.");
+
+        log_debug("Found default boot loader entry in file \"%s\"", e->path);
+
+        if (!e->kernel)
+                return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
+                                       "Boot entry does not refer to Linux kernel, which is not supported currently.");
+        if (strv_length(e->initrd) > 1)
+                return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
+                                       "Boot entry specifies multiple initrds, which is not supported currently.");
+
+        kernel = path_join(e->root, e->kernel);
+        if (!kernel)
+                return log_oom();
+
+        if (!strv_isempty(e->initrd)) {
+                initrd = path_join(e->root, e->initrd[0]);
+                if (!initrd)
+                        return log_oom();
+        }
+
+        options = strv_join(e->options, " ");
+        if (!options)
+                return log_oom();
+
+        log_full(arg_quiet ? LOG_DEBUG : LOG_INFO,
+                 "%s "KEXEC" --load \"%s\" --append \"%s\"%s%s%s",
+                 arg_dry_run ? "Would run" : "Running",
+                 kernel,
+                 options,
+                 initrd ? " --initrd \"" : NULL, strempty(initrd), initrd ? "\"" : "");
+        if (arg_dry_run)
+                return 0;
+
+        r = safe_fork("(kexec)", FORK_WAIT|FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_RLIMIT_NOFILE_SAFE|FORK_LOG, &pid);
+        if (r < 0)
+                return r;
+        if (r == 0) {
+                const char* const args[] = {
+                        KEXEC,
+                        "--load", kernel,
+                        "--append", options,
+                        initrd ? "--initrd" : NULL, initrd,
+                        NULL
+                };
+
+                /* Child */
+                execv(args[0], (char * const *) args);
+                _exit(EXIT_FAILURE);
+        }
+
+        return 0;
+}
+
+static int set_exit_code(uint8_t code) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        sd_bus *bus;
+        int r;
+
+        r = acquire_bus(BUS_MANAGER, &bus);
+        if (r < 0)
+                return r;
+
+        r = bus_call_method(bus, bus_systemd_mgr, "SetExitCode", &error, NULL, "y", code);
+        if (r < 0)
+                return log_error_errno(r, "Failed to set exit code: %s", bus_error_message(&error, r));
+
+        return 0;
+}
+
+int start_special(int argc, char *argv[], void *userdata) {
+        bool termination_action; /* An action that terminates the manager, can be performed also by
+                                  * signal. */
+        enum action a;
+        int r;
+
+        assert(argv);
+
+        a = verb_to_action(argv[0]);
+
+        r = logind_check_inhibitors(a);
+        if (r < 0)
+                return r;
+
+        if (arg_force >= 2) {
+                r = must_be_root();
+                if (r < 0)
+                        return r;
+        }
+
+        r = prepare_firmware_setup();
+        if (r < 0)
+                return r;
+
+        r = prepare_boot_loader_menu();
+        if (r < 0)
+                return r;
+
+        r = prepare_boot_loader_entry();
+        if (r < 0)
+                return r;
+
+        if (a == ACTION_REBOOT) {
+                const char *arg = NULL;
+
+                if (argc > 1) {
+                        if (arg_reboot_argument)
+                                return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Both --reboot-argument= and positional argument passed to reboot command, refusing.");
+
+                        log_notice("Positional argument to reboot command is deprecated, please use --reboot-argument= instead. Accepting anyway.");
+                        arg = argv[1];
+                } else
+                        arg = arg_reboot_argument;
+
+                if (arg) {
+                        r = update_reboot_parameter_and_warn(arg, false);
+                        if (r < 0)
+                                return r;
+                }
+
+        } else if (a == ACTION_KEXEC) {
+                r = load_kexec_kernel();
+                if (r < 0 && arg_force >= 1)
+                        log_notice("Failed to load kexec kernel, continuing without.");
+                else if (r < 0)
+                        return r;
+
+        } else if (a == ACTION_EXIT && argc > 1) {
+                uint8_t code;
+
+                /* If the exit code is not given on the command line, don't reset it to zero: just keep it as
+                 * it might have been set previously. */
+
+                r = safe_atou8(argv[1], &code);
+                if (r < 0)
+                        return log_error_errno(r, "Invalid exit code.");
+
+                r = set_exit_code(code);
+                if (r < 0)
+                        return r;
+        }
+
+        termination_action = IN_SET(a,
+                                    ACTION_HALT,
+                                    ACTION_POWEROFF,
+                                    ACTION_REBOOT);
+        if (termination_action && arg_force >= 2)
+                return halt_now(a);
+
+        if (arg_force >= 1 &&
+            (termination_action || IN_SET(a, ACTION_KEXEC, ACTION_EXIT)))
+                r = trivial_method(argc, argv, userdata);
+        else {
+                /* First try logind, to allow authentication with polkit */
+                if (IN_SET(a,
+                           ACTION_POWEROFF,
+                           ACTION_REBOOT,
+                           ACTION_HALT,
+                           ACTION_SUSPEND,
+                           ACTION_HIBERNATE,
+                           ACTION_HYBRID_SLEEP,
+                           ACTION_SUSPEND_THEN_HIBERNATE)) {
+
+                        r = logind_reboot(a);
+                        if (r >= 0)
+                                return r;
+                        if (IN_SET(r, -EOPNOTSUPP, -EINPROGRESS))
+                                /* Requested operation is not supported or already in progress */
+                                return r;
+
+                        /* On all other errors, try low-level operation. In order to minimize the difference
+                         * between operation with and without logind, we explicitly enable non-blocking mode
+                         * for this, as logind's shutdown operations are always non-blocking. */
+
+                        arg_no_block = true;
+
+                } else if (IN_SET(a, ACTION_EXIT, ACTION_KEXEC))
+                        /* Since exit/kexec are so close in behaviour to power-off/reboot, let's also make
+                         * them asynchronous, in order to not confuse the user needlessly with unexpected
+                         * behaviour. */
+                        arg_no_block = true;
+
+                r = start_unit(argc, argv, userdata);
+        }
+
+        if (termination_action && arg_force < 2 &&
+            IN_SET(r, -ENOENT, -ETIMEDOUT))
+                log_notice("It is possible to perform action directly, see discussion of --force --force in man:systemctl(1).");
+
+        return r;
+}
+
+int start_system_special(int argc, char *argv[], void *userdata) {
+        /* Like start_special above, but raises an error when running in user mode */
+
+        if (arg_scope != UNIT_FILE_SYSTEM)
+                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "Bad action for %s mode.",
+                                       arg_scope == UNIT_FILE_GLOBAL ? "--global" : "--user");
+
+        return start_special(argc, argv, userdata);
+}