diff options
Diffstat (limited to 'src/core/swap.c')
| -rw-r--r-- | src/core/swap.c | 1555 |
1 files changed, 1555 insertions, 0 deletions
diff --git a/src/core/swap.c b/src/core/swap.c new file mode 100644 index 0000000..2d8463b --- /dev/null +++ b/src/core/swap.c @@ -0,0 +1,1555 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include <errno.h> +#include <sys/epoll.h> +#include <sys/stat.h> +#include <unistd.h> + +#include "sd-device.h" + +#include "alloc-util.h" +#include "dbus-swap.h" +#include "dbus-unit.h" +#include "device-private.h" +#include "device-util.h" +#include "device.h" +#include "escape.h" +#include "exit-status.h" +#include "fd-util.h" +#include "format-util.h" +#include "fstab-util.h" +#include "parse-util.h" +#include "path-util.h" +#include "process-util.h" +#include "serialize.h" +#include "special.h" +#include "string-table.h" +#include "string-util.h" +#include "swap.h" +#include "unit-name.h" +#include "unit.h" +#include "virt.h" + +static const UnitActiveState state_translation_table[_SWAP_STATE_MAX] = { + [SWAP_DEAD] = UNIT_INACTIVE, + [SWAP_ACTIVATING] = UNIT_ACTIVATING, + [SWAP_ACTIVATING_DONE] = UNIT_ACTIVE, + [SWAP_ACTIVE] = UNIT_ACTIVE, + [SWAP_DEACTIVATING] = UNIT_DEACTIVATING, + [SWAP_DEACTIVATING_SIGTERM] = UNIT_DEACTIVATING, + [SWAP_DEACTIVATING_SIGKILL] = UNIT_DEACTIVATING, + [SWAP_FAILED] = UNIT_FAILED +}; + +static int swap_dispatch_timer(sd_event_source *source, usec_t usec, void *userdata); +static int swap_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata); + +static bool SWAP_STATE_WITH_PROCESS(SwapState state) { + return IN_SET(state, + SWAP_ACTIVATING, + SWAP_ACTIVATING_DONE, + SWAP_DEACTIVATING, + SWAP_DEACTIVATING_SIGTERM, + SWAP_DEACTIVATING_SIGKILL); +} + +static void swap_unset_proc_swaps(Swap *s) { + assert(s); + + if (!s->from_proc_swaps) + return; + + s->parameters_proc_swaps.what = mfree(s->parameters_proc_swaps.what); + + s->from_proc_swaps = false; +} + +static int swap_set_devnode(Swap *s, const char *devnode) { + Hashmap *swaps; + Swap *first; + int r; + + assert(s); + + r = hashmap_ensure_allocated(&UNIT(s)->manager->swaps_by_devnode, &path_hash_ops); + if (r < 0) + return r; + + swaps = UNIT(s)->manager->swaps_by_devnode; + + if (s->devnode) { + first = hashmap_get(swaps, s->devnode); + + LIST_REMOVE(same_devnode, first, s); + if (first) + hashmap_replace(swaps, first->devnode, first); + else + hashmap_remove(swaps, s->devnode); + + s->devnode = mfree(s->devnode); + } + + if (devnode) { + s->devnode = strdup(devnode); + if (!s->devnode) + return -ENOMEM; + + first = hashmap_get(swaps, s->devnode); + LIST_PREPEND(same_devnode, first, s); + + return hashmap_replace(swaps, first->devnode, first); + } + + return 0; +} + +static void swap_init(Unit *u) { + Swap *s = SWAP(u); + + assert(s); + assert(UNIT(s)->load_state == UNIT_STUB); + + s->timeout_usec = u->manager->default_timeout_start_usec; + + s->exec_context.std_output = u->manager->default_std_output; + s->exec_context.std_error = u->manager->default_std_error; + + s->parameters_proc_swaps.priority = s->parameters_fragment.priority = -1; + + s->control_command_id = _SWAP_EXEC_COMMAND_INVALID; + + u->ignore_on_isolate = true; +} + +static void swap_unwatch_control_pid(Swap *s) { + assert(s); + + if (s->control_pid <= 0) + return; + + unit_unwatch_pid(UNIT(s), s->control_pid); + s->control_pid = 0; +} + +static void swap_done(Unit *u) { + Swap *s = SWAP(u); + + assert(s); + + swap_unset_proc_swaps(s); + swap_set_devnode(s, NULL); + + s->what = mfree(s->what); + s->parameters_fragment.what = mfree(s->parameters_fragment.what); + s->parameters_fragment.options = mfree(s->parameters_fragment.options); + + s->exec_runtime = exec_runtime_unref(s->exec_runtime, false); + exec_command_done_array(s->exec_command, _SWAP_EXEC_COMMAND_MAX); + s->control_command = NULL; + + dynamic_creds_unref(&s->dynamic_creds); + + swap_unwatch_control_pid(s); + + s->timer_event_source = sd_event_source_unref(s->timer_event_source); +} + +static int swap_arm_timer(Swap *s, usec_t usec) { + int r; + + assert(s); + + if (s->timer_event_source) { + r = sd_event_source_set_time(s->timer_event_source, usec); + if (r < 0) + return r; + + return sd_event_source_set_enabled(s->timer_event_source, SD_EVENT_ONESHOT); + } + + if (usec == USEC_INFINITY) + return 0; + + r = sd_event_add_time( + UNIT(s)->manager->event, + &s->timer_event_source, + CLOCK_MONOTONIC, + usec, 0, + swap_dispatch_timer, s); + if (r < 0) + return r; + + (void) sd_event_source_set_description(s->timer_event_source, "swap-timer"); + + return 0; +} + +static int swap_add_device_dependencies(Swap *s) { + assert(s); + + if (!s->what) + return 0; + + if (!s->from_fragment) + return 0; + + if (is_device_path(s->what)) + return unit_add_node_dependency(UNIT(s), s->what, MANAGER_IS_SYSTEM(UNIT(s)->manager), UNIT_BINDS_TO, UNIT_DEPENDENCY_FILE); + else + /* File based swap devices need to be ordered after + * systemd-remount-fs.service, since they might need a + * writable file system. */ + return unit_add_dependency_by_name(UNIT(s), UNIT_AFTER, SPECIAL_REMOUNT_FS_SERVICE, true, UNIT_DEPENDENCY_FILE); +} + +static int swap_add_default_dependencies(Swap *s) { + int r; + + assert(s); + + if (!UNIT(s)->default_dependencies) + return 0; + + if (!MANAGER_IS_SYSTEM(UNIT(s)->manager)) + return 0; + + if (detect_container() > 0) + return 0; + + /* swap units generated for the swap dev links are missing the + * ordering dep against the swap target. */ + r = unit_add_dependency_by_name(UNIT(s), UNIT_BEFORE, SPECIAL_SWAP_TARGET, true, UNIT_DEPENDENCY_DEFAULT); + if (r < 0) + return r; + + return unit_add_two_dependencies_by_name(UNIT(s), UNIT_BEFORE, UNIT_CONFLICTS, SPECIAL_UMOUNT_TARGET, true, UNIT_DEPENDENCY_DEFAULT); +} + +static int swap_verify(Swap *s) { + _cleanup_free_ char *e = NULL; + int r; + + if (UNIT(s)->load_state != UNIT_LOADED) + return 0; + + r = unit_name_from_path(s->what, ".swap", &e); + if (r < 0) + return log_unit_error_errno(UNIT(s), r, "Failed to generate unit name from path: %m"); + + if (!unit_has_name(UNIT(s), e)) { + log_unit_error(UNIT(s), "Value of What= and unit name do not match, not loading."); + return -ENOEXEC; + } + + if (s->exec_context.pam_name && s->kill_context.kill_mode != KILL_CONTROL_GROUP) { + log_unit_error(UNIT(s), "Unit has PAM enabled. Kill mode must be set to 'control-group'. Refusing to load."); + return -ENOEXEC; + } + + return 0; +} + +static int swap_load_devnode(Swap *s) { + _cleanup_(sd_device_unrefp) sd_device *d = NULL; + struct stat st; + const char *p; + int r; + + assert(s); + + if (stat(s->what, &st) < 0 || !S_ISBLK(st.st_mode)) + return 0; + + r = device_new_from_stat_rdev(&d, &st); + if (r < 0) { + log_unit_full(UNIT(s), r == -ENOENT ? LOG_DEBUG : LOG_WARNING, r, + "Failed to allocate device for swap %s: %m", s->what); + return 0; + } + + if (sd_device_get_devname(d, &p) < 0) + return 0; + + return swap_set_devnode(s, p); +} + +static int swap_add_extras(Swap *s) { + int r; + + assert(s); + + if (UNIT(s)->fragment_path) + s->from_fragment = true; + + if (!s->what) { + if (s->parameters_fragment.what) + s->what = strdup(s->parameters_fragment.what); + else if (s->parameters_proc_swaps.what) + s->what = strdup(s->parameters_proc_swaps.what); + else { + r = unit_name_to_path(UNIT(s)->id, &s->what); + if (r < 0) + return r; + } + + if (!s->what) + return -ENOMEM; + } + + path_simplify(s->what, false); + + if (!UNIT(s)->description) { + r = unit_set_description(UNIT(s), s->what); + if (r < 0) + return r; + } + + r = unit_require_mounts_for(UNIT(s), s->what, UNIT_DEPENDENCY_IMPLICIT); + if (r < 0) + return r; + + r = swap_add_device_dependencies(s); + if (r < 0) + return r; + + r = swap_load_devnode(s); + if (r < 0) + return r; + + r = unit_patch_contexts(UNIT(s)); + if (r < 0) + return r; + + r = unit_add_exec_dependencies(UNIT(s), &s->exec_context); + if (r < 0) + return r; + + r = unit_set_default_slice(UNIT(s)); + if (r < 0) + return r; + + r = swap_add_default_dependencies(s); + if (r < 0) + return r; + + return 0; +} + +static int swap_load(Unit *u) { + Swap *s = SWAP(u); + int r, q; + + assert(s); + assert(u->load_state == UNIT_STUB); + + /* Load a .swap file */ + if (SWAP(u)->from_proc_swaps) + r = unit_load_fragment_and_dropin_optional(u); + else + r = unit_load_fragment_and_dropin(u); + + /* Add in some extras, and do so either when we successfully loaded something or when /proc/swaps is already + * active. */ + if (u->load_state == UNIT_LOADED || s->from_proc_swaps) + q = swap_add_extras(s); + else + q = 0; + + if (r < 0) + return r; + if (q < 0) + return q; + + return swap_verify(s); +} + +static int swap_setup_unit( + Manager *m, + const char *what, + const char *what_proc_swaps, + int priority, + bool set_flags) { + + _cleanup_free_ char *e = NULL; + bool delete = false; + Unit *u = NULL; + int r; + SwapParameters *p; + + assert(m); + assert(what); + assert(what_proc_swaps); + + r = unit_name_from_path(what, ".swap", &e); + if (r < 0) + return log_unit_error_errno(u, r, "Failed to generate unit name from path: %m"); + + u = manager_get_unit(m, e); + if (u && + SWAP(u)->from_proc_swaps && + !path_equal(SWAP(u)->parameters_proc_swaps.what, what_proc_swaps)) + return log_error_errno(SYNTHETIC_ERRNO(EEXIST), + "Swap %s appeared twice with different device paths %s and %s", + e, SWAP(u)->parameters_proc_swaps.what, what_proc_swaps); + + if (!u) { + delete = true; + + r = unit_new_for_name(m, sizeof(Swap), e, &u); + if (r < 0) + goto fail; + + SWAP(u)->what = strdup(what); + if (!SWAP(u)->what) { + r = -ENOMEM; + goto fail; + } + + unit_add_to_load_queue(u); + } else + delete = false; + + p = &SWAP(u)->parameters_proc_swaps; + + if (!p->what) { + p->what = strdup(what_proc_swaps); + if (!p->what) { + r = -ENOMEM; + goto fail; + } + } + + /* The unit is definitely around now, mark it as loaded if it was previously referenced but could not be + * loaded. After all we can load it now, from the data in /proc/swaps. */ + if (IN_SET(u->load_state, UNIT_NOT_FOUND, UNIT_BAD_SETTING, UNIT_ERROR)) { + u->load_state = UNIT_LOADED; + u->load_error = 0; + } + + if (set_flags) { + SWAP(u)->is_active = true; + SWAP(u)->just_activated = !SWAP(u)->from_proc_swaps; + } + + SWAP(u)->from_proc_swaps = true; + + p->priority = priority; + + unit_add_to_dbus_queue(u); + return 0; + +fail: + log_unit_warning_errno(u, r, "Failed to load swap unit: %m"); + + if (delete) + unit_free(u); + + return r; +} + +static int swap_process_new(Manager *m, const char *device, int prio, bool set_flags) { + _cleanup_(sd_device_unrefp) sd_device *d = NULL; + const char *dn, *devlink; + struct stat st, st_link; + int r; + + assert(m); + + r = swap_setup_unit(m, device, device, prio, set_flags); + if (r < 0) + return r; + + /* If this is a block device, then let's add duplicates for + * all other names of this block device */ + if (stat(device, &st) < 0 || !S_ISBLK(st.st_mode)) + return 0; + + r = device_new_from_stat_rdev(&d, &st); + if (r < 0) { + log_full_errno(r == -ENOENT ? LOG_DEBUG : LOG_WARNING, r, + "Failed to allocate device for swap %s: %m", device); + return 0; + } + + /* Add the main device node */ + if (sd_device_get_devname(d, &dn) >= 0 && !streq(dn, device)) + swap_setup_unit(m, dn, device, prio, set_flags); + + /* Add additional units for all symlinks */ + FOREACH_DEVICE_DEVLINK(d, devlink) { + + /* Don't bother with the /dev/block links */ + if (streq(devlink, device)) + continue; + + if (path_startswith(devlink, "/dev/block/")) + continue; + + if (stat(devlink, &st_link) >= 0 && + (!S_ISBLK(st_link.st_mode) || + st_link.st_rdev != st.st_rdev)) + continue; + + swap_setup_unit(m, devlink, device, prio, set_flags); + } + + return 0; +} + +static void swap_set_state(Swap *s, SwapState state) { + SwapState old_state; + Swap *other; + + assert(s); + + if (s->state != state) + bus_unit_send_pending_change_signal(UNIT(s), false); + + old_state = s->state; + s->state = state; + + if (!SWAP_STATE_WITH_PROCESS(state)) { + s->timer_event_source = sd_event_source_unref(s->timer_event_source); + swap_unwatch_control_pid(s); + s->control_command = NULL; + s->control_command_id = _SWAP_EXEC_COMMAND_INVALID; + } + + if (state != old_state) + log_unit_debug(UNIT(s), "Changed %s -> %s", swap_state_to_string(old_state), swap_state_to_string(state)); + + unit_notify(UNIT(s), state_translation_table[old_state], state_translation_table[state], 0); + + /* If there other units for the same device node have a job + queued it might be worth checking again if it is runnable + now. This is necessary, since swap_start() refuses + operation with EAGAIN if there's already another job for + the same device node queued. */ + LIST_FOREACH_OTHERS(same_devnode, other, s) + if (UNIT(other)->job) + job_add_to_run_queue(UNIT(other)->job); +} + +static int swap_coldplug(Unit *u) { + Swap *s = SWAP(u); + SwapState new_state = SWAP_DEAD; + int r; + + assert(s); + assert(s->state == SWAP_DEAD); + + if (s->deserialized_state != s->state) + new_state = s->deserialized_state; + else if (s->from_proc_swaps) + new_state = SWAP_ACTIVE; + + if (new_state == s->state) + return 0; + + if (s->control_pid > 0 && + pid_is_unwaited(s->control_pid) && + SWAP_STATE_WITH_PROCESS(new_state)) { + + r = unit_watch_pid(UNIT(s), s->control_pid); + if (r < 0) + return r; + + r = swap_arm_timer(s, usec_add(u->state_change_timestamp.monotonic, s->timeout_usec)); + if (r < 0) + return r; + } + + if (!IN_SET(new_state, SWAP_DEAD, SWAP_FAILED)) { + (void) unit_setup_dynamic_creds(u); + (void) unit_setup_exec_runtime(u); + } + + swap_set_state(s, new_state); + return 0; +} + +static void swap_dump(Unit *u, FILE *f, const char *prefix) { + char buf[FORMAT_TIMESPAN_MAX]; + Swap *s = SWAP(u); + SwapParameters *p; + + assert(s); + assert(f); + + if (s->from_proc_swaps) + p = &s->parameters_proc_swaps; + else if (s->from_fragment) + p = &s->parameters_fragment; + else + p = NULL; + + fprintf(f, + "%sSwap State: %s\n" + "%sResult: %s\n" + "%sWhat: %s\n" + "%sFrom /proc/swaps: %s\n" + "%sFrom fragment: %s\n", + prefix, swap_state_to_string(s->state), + prefix, swap_result_to_string(s->result), + prefix, s->what, + prefix, yes_no(s->from_proc_swaps), + prefix, yes_no(s->from_fragment)); + + if (s->devnode) + fprintf(f, "%sDevice Node: %s\n", prefix, s->devnode); + + if (p) + fprintf(f, + "%sPriority: %i\n" + "%sOptions: %s\n", + prefix, p->priority, + prefix, strempty(p->options)); + + fprintf(f, + "%sTimeoutSec: %s\n", + prefix, format_timespan(buf, sizeof(buf), s->timeout_usec, USEC_PER_SEC)); + + if (s->control_pid > 0) + fprintf(f, + "%sControl PID: "PID_FMT"\n", + prefix, s->control_pid); + + exec_context_dump(&s->exec_context, f, prefix); + kill_context_dump(&s->kill_context, f, prefix); + cgroup_context_dump(&s->cgroup_context, f, prefix); +} + +static int swap_spawn(Swap *s, ExecCommand *c, pid_t *_pid) { + + _cleanup_(exec_params_clear) ExecParameters exec_params = { + .flags = EXEC_APPLY_SANDBOXING|EXEC_APPLY_CHROOT|EXEC_APPLY_TTY_STDIN, + .stdin_fd = -1, + .stdout_fd = -1, + .stderr_fd = -1, + .exec_fd = -1, + }; + pid_t pid; + int r; + + assert(s); + assert(c); + assert(_pid); + + r = unit_prepare_exec(UNIT(s)); + if (r < 0) + return r; + + r = swap_arm_timer(s, usec_add(now(CLOCK_MONOTONIC), s->timeout_usec)); + if (r < 0) + goto fail; + + r = unit_set_exec_params(UNIT(s), &exec_params); + if (r < 0) + goto fail; + + r = exec_spawn(UNIT(s), + c, + &s->exec_context, + &exec_params, + s->exec_runtime, + &s->dynamic_creds, + &pid); + if (r < 0) + goto fail; + + r = unit_watch_pid(UNIT(s), pid); + if (r < 0) + /* FIXME: we need to do something here */ + goto fail; + + *_pid = pid; + + return 0; + +fail: + s->timer_event_source = sd_event_source_unref(s->timer_event_source); + + return r; +} + +static void swap_enter_dead(Swap *s, SwapResult f) { + assert(s); + + if (s->result == SWAP_SUCCESS) + s->result = f; + + unit_log_result(UNIT(s), s->result == SWAP_SUCCESS, swap_result_to_string(s->result)); + swap_set_state(s, s->result != SWAP_SUCCESS ? SWAP_FAILED : SWAP_DEAD); + + s->exec_runtime = exec_runtime_unref(s->exec_runtime, true); + + exec_context_destroy_runtime_directory(&s->exec_context, UNIT(s)->manager->prefix[EXEC_DIRECTORY_RUNTIME]); + + unit_unref_uid_gid(UNIT(s), true); + + dynamic_creds_destroy(&s->dynamic_creds); +} + +static void swap_enter_active(Swap *s, SwapResult f) { + assert(s); + + if (s->result == SWAP_SUCCESS) + s->result = f; + + swap_set_state(s, SWAP_ACTIVE); +} + +static void swap_enter_dead_or_active(Swap *s, SwapResult f) { + assert(s); + + if (s->from_proc_swaps) + swap_enter_active(s, f); + else + swap_enter_dead(s, f); +} + +static void swap_enter_signal(Swap *s, SwapState state, SwapResult f) { + int r; + KillOperation kop; + + assert(s); + + if (s->result == SWAP_SUCCESS) + s->result = f; + + if (state == SWAP_DEACTIVATING_SIGTERM) + kop = KILL_TERMINATE; + else + kop = KILL_KILL; + + r = unit_kill_context(UNIT(s), &s->kill_context, kop, -1, s->control_pid, false); + if (r < 0) + goto fail; + + if (r > 0) { + r = swap_arm_timer(s, usec_add(now(CLOCK_MONOTONIC), s->timeout_usec)); + if (r < 0) + goto fail; + + swap_set_state(s, state); + } else if (state == SWAP_DEACTIVATING_SIGTERM && s->kill_context.send_sigkill) + swap_enter_signal(s, SWAP_DEACTIVATING_SIGKILL, SWAP_SUCCESS); + else + swap_enter_dead_or_active(s, SWAP_SUCCESS); + + return; + +fail: + log_unit_warning_errno(UNIT(s), r, "Failed to kill processes: %m"); + swap_enter_dead_or_active(s, SWAP_FAILURE_RESOURCES); +} + +static void swap_enter_activating(Swap *s) { + _cleanup_free_ char *opts = NULL; + int r; + + assert(s); + + unit_warn_leftover_processes(UNIT(s)); + + s->control_command_id = SWAP_EXEC_ACTIVATE; + s->control_command = s->exec_command + SWAP_EXEC_ACTIVATE; + + if (s->from_fragment) { + int priority = -1; + + r = fstab_find_pri(s->parameters_fragment.options, &priority); + if (r < 0) + log_warning_errno(r, "Failed to parse swap priority \"%s\", ignoring: %m", s->parameters_fragment.options); + else if (r == 1 && s->parameters_fragment.priority >= 0) + log_warning("Duplicate swap priority configuration by Priority and Options fields."); + + if (r <= 0 && s->parameters_fragment.priority >= 0) { + if (s->parameters_fragment.options) + r = asprintf(&opts, "%s,pri=%i", s->parameters_fragment.options, s->parameters_fragment.priority); + else + r = asprintf(&opts, "pri=%i", s->parameters_fragment.priority); + if (r < 0) + goto fail; + } + } + + r = exec_command_set(s->control_command, "/sbin/swapon", NULL); + if (r < 0) + goto fail; + + if (s->parameters_fragment.options || opts) { + r = exec_command_append(s->control_command, "-o", + opts ? : s->parameters_fragment.options, NULL); + if (r < 0) + goto fail; + } + + r = exec_command_append(s->control_command, s->what, NULL); + if (r < 0) + goto fail; + + swap_unwatch_control_pid(s); + + r = swap_spawn(s, s->control_command, &s->control_pid); + if (r < 0) + goto fail; + + swap_set_state(s, SWAP_ACTIVATING); + + return; + +fail: + log_unit_warning_errno(UNIT(s), r, "Failed to run 'swapon' task: %m"); + swap_enter_dead_or_active(s, SWAP_FAILURE_RESOURCES); +} + +static void swap_enter_deactivating(Swap *s) { + int r; + + assert(s); + + s->control_command_id = SWAP_EXEC_DEACTIVATE; + s->control_command = s->exec_command + SWAP_EXEC_DEACTIVATE; + + r = exec_command_set(s->control_command, + "/sbin/swapoff", + s->what, + NULL); + if (r < 0) + goto fail; + + swap_unwatch_control_pid(s); + + r = swap_spawn(s, s->control_command, &s->control_pid); + if (r < 0) + goto fail; + + swap_set_state(s, SWAP_DEACTIVATING); + + return; + +fail: + log_unit_warning_errno(UNIT(s), r, "Failed to run 'swapoff' task: %m"); + swap_enter_dead_or_active(s, SWAP_FAILURE_RESOURCES); +} + +static void swap_cycle_clear(Swap *s) { + assert(s); + + s->result = SWAP_SUCCESS; + exec_command_reset_status_array(s->exec_command, _SWAP_EXEC_COMMAND_MAX); + UNIT(s)->reset_accounting = true; +} + +static int swap_start(Unit *u) { + Swap *s = SWAP(u), *other; + int r; + + assert(s); + + /* We cannot fulfill this request right now, try again later please! */ + if (IN_SET(s->state, + SWAP_DEACTIVATING, + SWAP_DEACTIVATING_SIGTERM, + SWAP_DEACTIVATING_SIGKILL)) + return -EAGAIN; + + /* Already on it! */ + if (s->state == SWAP_ACTIVATING) + return 0; + + assert(IN_SET(s->state, SWAP_DEAD, SWAP_FAILED)); + + if (detect_container() > 0) + return -EPERM; + + /* If there's a job for another swap unit for the same node + * running, then let's not dispatch this one for now, and wait + * until that other job has finished. */ + LIST_FOREACH_OTHERS(same_devnode, other, s) + if (UNIT(other)->job && UNIT(other)->job->state == JOB_RUNNING) + return -EAGAIN; + + r = unit_start_limit_test(u); + if (r < 0) { + swap_enter_dead(s, SWAP_FAILURE_START_LIMIT_HIT); + return r; + } + + r = unit_acquire_invocation_id(u); + if (r < 0) + return r; + + swap_cycle_clear(s); + swap_enter_activating(s); + return 1; +} + +static int swap_stop(Unit *u) { + Swap *s = SWAP(u); + + assert(s); + + switch (s->state) { + + case SWAP_DEACTIVATING: + case SWAP_DEACTIVATING_SIGTERM: + case SWAP_DEACTIVATING_SIGKILL: + /* Already on it */ + return 0; + + case SWAP_ACTIVATING: + case SWAP_ACTIVATING_DONE: + /* There's a control process pending, directly enter kill mode */ + swap_enter_signal(s, SWAP_DEACTIVATING_SIGTERM, SWAP_SUCCESS); + return 0; + + case SWAP_ACTIVE: + if (detect_container() > 0) + return -EPERM; + + swap_enter_deactivating(s); + return 1; + + default: + assert_not_reached("Unexpected state."); + } +} + +static int swap_serialize(Unit *u, FILE *f, FDSet *fds) { + Swap *s = SWAP(u); + + assert(s); + assert(f); + assert(fds); + + (void) serialize_item(f, "state", swap_state_to_string(s->state)); + (void) serialize_item(f, "result", swap_result_to_string(s->result)); + + if (s->control_pid > 0) + (void) serialize_item_format(f, "control-pid", PID_FMT, s->control_pid); + + if (s->control_command_id >= 0) + (void) serialize_item(f, "control-command", swap_exec_command_to_string(s->control_command_id)); + + return 0; +} + +static int swap_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) { + Swap *s = SWAP(u); + + assert(s); + assert(fds); + + if (streq(key, "state")) { + SwapState state; + + state = swap_state_from_string(value); + if (state < 0) + log_unit_debug(u, "Failed to parse state value: %s", value); + else + s->deserialized_state = state; + } else if (streq(key, "result")) { + SwapResult f; + + f = swap_result_from_string(value); + if (f < 0) + log_unit_debug(u, "Failed to parse result value: %s", value); + else if (f != SWAP_SUCCESS) + s->result = f; + } else if (streq(key, "control-pid")) { + pid_t pid; + + if (parse_pid(value, &pid) < 0) + log_unit_debug(u, "Failed to parse control-pid value: %s", value); + else + s->control_pid = pid; + + } else if (streq(key, "control-command")) { + SwapExecCommand id; + + id = swap_exec_command_from_string(value); + if (id < 0) + log_unit_debug(u, "Failed to parse exec-command value: %s", value); + else { + s->control_command_id = id; + s->control_command = s->exec_command + id; + } + } else + log_unit_debug(u, "Unknown serialization key: %s", key); + + return 0; +} + +_pure_ static UnitActiveState swap_active_state(Unit *u) { + assert(u); + + return state_translation_table[SWAP(u)->state]; +} + +_pure_ static const char *swap_sub_state_to_string(Unit *u) { + assert(u); + + return swap_state_to_string(SWAP(u)->state); +} + +_pure_ static bool swap_may_gc(Unit *u) { + Swap *s = SWAP(u); + + assert(s); + + if (s->from_proc_swaps) + return false; + + return true; +} + +static void swap_sigchld_event(Unit *u, pid_t pid, int code, int status) { + Swap *s = SWAP(u); + SwapResult f; + + assert(s); + assert(pid >= 0); + + if (pid != s->control_pid) + return; + + s->control_pid = 0; + + if (is_clean_exit(code, status, EXIT_CLEAN_COMMAND, NULL)) + f = SWAP_SUCCESS; + else if (code == CLD_EXITED) + f = SWAP_FAILURE_EXIT_CODE; + else if (code == CLD_KILLED) + f = SWAP_FAILURE_SIGNAL; + else if (code == CLD_DUMPED) + f = SWAP_FAILURE_CORE_DUMP; + else + assert_not_reached("Unknown code"); + + if (s->result == SWAP_SUCCESS) + s->result = f; + + if (s->control_command) { + exec_status_exit(&s->control_command->exec_status, &s->exec_context, pid, code, status); + + s->control_command = NULL; + s->control_command_id = _SWAP_EXEC_COMMAND_INVALID; + } + + unit_log_process_exit( + u, f == SWAP_SUCCESS ? LOG_DEBUG : LOG_NOTICE, + "Swap process", + swap_exec_command_to_string(s->control_command_id), + code, status); + + switch (s->state) { + + case SWAP_ACTIVATING: + case SWAP_ACTIVATING_DONE: + + if (f == SWAP_SUCCESS || s->from_proc_swaps) + swap_enter_active(s, f); + else + swap_enter_dead(s, f); + break; + + case SWAP_DEACTIVATING: + case SWAP_DEACTIVATING_SIGKILL: + case SWAP_DEACTIVATING_SIGTERM: + + swap_enter_dead_or_active(s, f); + break; + + default: + assert_not_reached("Uh, control process died at wrong time."); + } + + /* Notify clients about changed exit status */ + unit_add_to_dbus_queue(u); +} + +static int swap_dispatch_timer(sd_event_source *source, usec_t usec, void *userdata) { + Swap *s = SWAP(userdata); + + assert(s); + assert(s->timer_event_source == source); + + switch (s->state) { + + case SWAP_ACTIVATING: + case SWAP_ACTIVATING_DONE: + log_unit_warning(UNIT(s), "Activation timed out. Stopping."); + swap_enter_signal(s, SWAP_DEACTIVATING_SIGTERM, SWAP_FAILURE_TIMEOUT); + break; + + case SWAP_DEACTIVATING: + log_unit_warning(UNIT(s), "Deactivation timed out. Stopping."); + swap_enter_signal(s, SWAP_DEACTIVATING_SIGTERM, SWAP_FAILURE_TIMEOUT); + break; + + case SWAP_DEACTIVATING_SIGTERM: + if (s->kill_context.send_sigkill) { + log_unit_warning(UNIT(s), "Swap process timed out. Killing."); + swap_enter_signal(s, SWAP_DEACTIVATING_SIGKILL, SWAP_FAILURE_TIMEOUT); + } else { + log_unit_warning(UNIT(s), "Swap process timed out. Skipping SIGKILL. Ignoring."); + swap_enter_dead_or_active(s, SWAP_FAILURE_TIMEOUT); + } + break; + + case SWAP_DEACTIVATING_SIGKILL: + log_unit_warning(UNIT(s), "Swap process still around after SIGKILL. Ignoring."); + swap_enter_dead_or_active(s, SWAP_FAILURE_TIMEOUT); + break; + + default: + assert_not_reached("Timeout at wrong time."); + } + + return 0; +} + +static int swap_load_proc_swaps(Manager *m, bool set_flags) { + unsigned i; + + assert(m); + + rewind(m->proc_swaps); + + (void) fscanf(m->proc_swaps, "%*s %*s %*s %*s %*s\n"); + + for (i = 1;; i++) { + _cleanup_free_ char *dev = NULL, *d = NULL; + int prio = 0, k; + + k = fscanf(m->proc_swaps, + "%ms " /* device/file */ + "%*s " /* type of swap */ + "%*s " /* swap size */ + "%*s " /* used */ + "%i\n", /* priority */ + &dev, &prio); + if (k != 2) { + if (k == EOF) + break; + + log_warning("Failed to parse /proc/swaps:%u.", i); + continue; + } + + if (cunescape(dev, UNESCAPE_RELAX, &d) < 0) + return log_oom(); + + device_found_node(m, d, DEVICE_FOUND_SWAP, DEVICE_FOUND_SWAP); + + (void) swap_process_new(m, d, prio, set_flags); + } + + return 0; +} + +static int swap_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata) { + Manager *m = userdata; + Unit *u; + int r; + + assert(m); + assert(revents & EPOLLPRI); + + r = swap_load_proc_swaps(m, true); + if (r < 0) { + log_error_errno(r, "Failed to reread /proc/swaps: %m"); + + /* Reset flags, just in case, for late calls */ + LIST_FOREACH(units_by_type, u, m->units_by_type[UNIT_SWAP]) { + Swap *swap = SWAP(u); + + swap->is_active = swap->just_activated = false; + } + + return 0; + } + + manager_dispatch_load_queue(m); + + LIST_FOREACH(units_by_type, u, m->units_by_type[UNIT_SWAP]) { + Swap *swap = SWAP(u); + + if (!swap->is_active) { + + swap_unset_proc_swaps(swap); + + switch (swap->state) { + + case SWAP_ACTIVE: + /* This has just been deactivated */ + swap_enter_dead(swap, SWAP_SUCCESS); + break; + + default: + /* Fire again */ + swap_set_state(swap, swap->state); + break; + } + + if (swap->what) + device_found_node(m, swap->what, 0, DEVICE_FOUND_SWAP); + + } else if (swap->just_activated) { + + /* New swap entry */ + + switch (swap->state) { + + case SWAP_DEAD: + case SWAP_FAILED: + (void) unit_acquire_invocation_id(u); + swap_cycle_clear(swap); + swap_enter_active(swap, SWAP_SUCCESS); + break; + + case SWAP_ACTIVATING: + swap_set_state(swap, SWAP_ACTIVATING_DONE); + break; + + default: + /* Nothing really changed, but let's + * issue an notification call + * nonetheless, in case somebody is + * waiting for this. */ + swap_set_state(swap, swap->state); + break; + } + } + + /* Reset the flags for later calls */ + swap->is_active = swap->just_activated = false; + } + + return 1; +} + +static Unit *swap_following(Unit *u) { + Swap *s = SWAP(u); + Swap *other, *first = NULL; + + assert(s); + + /* If the user configured the swap through /etc/fstab or + * a device unit, follow that. */ + + if (s->from_fragment) + return NULL; + + LIST_FOREACH_OTHERS(same_devnode, other, s) + if (other->from_fragment) + return UNIT(other); + + /* Otherwise, make everybody follow the unit that's named after + * the swap device in the kernel */ + + if (streq_ptr(s->what, s->devnode)) + return NULL; + + LIST_FOREACH_AFTER(same_devnode, other, s) + if (streq_ptr(other->what, other->devnode)) + return UNIT(other); + + LIST_FOREACH_BEFORE(same_devnode, other, s) { + if (streq_ptr(other->what, other->devnode)) + return UNIT(other); + + first = other; + } + + /* Fall back to the first on the list */ + return UNIT(first); +} + +static int swap_following_set(Unit *u, Set **_set) { + Swap *s = SWAP(u), *other; + _cleanup_set_free_ Set *set = NULL; + int r; + + assert(s); + assert(_set); + + if (LIST_JUST_US(same_devnode, s)) { + *_set = NULL; + return 0; + } + + set = set_new(NULL); + if (!set) + return -ENOMEM; + + LIST_FOREACH_OTHERS(same_devnode, other, s) { + r = set_put(set, other); + if (r < 0) + return r; + } + + *_set = TAKE_PTR(set); + return 1; +} + +static void swap_shutdown(Manager *m) { + assert(m); + + m->swap_event_source = sd_event_source_unref(m->swap_event_source); + m->proc_swaps = safe_fclose(m->proc_swaps); + m->swaps_by_devnode = hashmap_free(m->swaps_by_devnode); +} + +static void swap_enumerate(Manager *m) { + int r; + + assert(m); + + if (!m->proc_swaps) { + m->proc_swaps = fopen("/proc/swaps", "re"); + if (!m->proc_swaps) { + if (errno == ENOENT) + log_debug_errno(errno, "Not swap enabled, skipping enumeration."); + else + log_warning_errno(errno, "Failed to open /proc/swaps, ignoring: %m"); + + return; + } + + r = sd_event_add_io(m->event, &m->swap_event_source, fileno(m->proc_swaps), EPOLLPRI, swap_dispatch_io, m); + if (r < 0) { + log_error_errno(r, "Failed to watch /proc/swaps: %m"); + goto fail; + } + + /* Dispatch this before we dispatch SIGCHLD, so that + * we always get the events from /proc/swaps before + * the SIGCHLD of /sbin/swapon. */ + r = sd_event_source_set_priority(m->swap_event_source, SD_EVENT_PRIORITY_NORMAL-10); + if (r < 0) { + log_error_errno(r, "Failed to change /proc/swaps priority: %m"); + goto fail; + } + + (void) sd_event_source_set_description(m->swap_event_source, "swap-proc"); + } + + r = swap_load_proc_swaps(m, false); + if (r < 0) + goto fail; + + return; + +fail: + swap_shutdown(m); +} + +int swap_process_device_new(Manager *m, sd_device *dev) { + _cleanup_free_ char *e = NULL; + const char *dn, *devlink; + Unit *u; + int r = 0; + + assert(m); + assert(dev); + + r = sd_device_get_devname(dev, &dn); + if (r < 0) + return 0; + + r = unit_name_from_path(dn, ".swap", &e); + if (r < 0) + return r; + + u = manager_get_unit(m, e); + if (u) + r = swap_set_devnode(SWAP(u), dn); + + FOREACH_DEVICE_DEVLINK(dev, devlink) { + _cleanup_free_ char *n = NULL; + int q; + + q = unit_name_from_path(devlink, ".swap", &n); + if (q < 0) + return q; + + u = manager_get_unit(m, n); + if (u) { + q = swap_set_devnode(SWAP(u), dn); + if (q < 0) + r = q; + } + } + + return r; +} + +int swap_process_device_remove(Manager *m, sd_device *dev) { + const char *dn; + int r = 0; + Swap *s; + + r = sd_device_get_devname(dev, &dn); + if (r < 0) + return 0; + + while ((s = hashmap_get(m->swaps_by_devnode, dn))) { + int q; + + q = swap_set_devnode(s, NULL); + if (q < 0) + r = q; + } + + return r; +} + +static void swap_reset_failed(Unit *u) { + Swap *s = SWAP(u); + + assert(s); + + if (s->state == SWAP_FAILED) + swap_set_state(s, SWAP_DEAD); + + s->result = SWAP_SUCCESS; +} + +static int swap_kill(Unit *u, KillWho who, int signo, sd_bus_error *error) { + return unit_kill_common(u, who, signo, -1, SWAP(u)->control_pid, error); +} + +static int swap_get_timeout(Unit *u, usec_t *timeout) { + Swap *s = SWAP(u); + usec_t t; + int r; + + if (!s->timer_event_source) + return 0; + + r = sd_event_source_get_time(s->timer_event_source, &t); + if (r < 0) + return r; + if (t == USEC_INFINITY) + return 0; + + *timeout = t; + return 1; +} + +static bool swap_supported(void) { + static int supported = -1; + + /* If swap support is not available in the kernel, or we are + * running in a container we don't support swap units, and any + * attempts to starting one should fail immediately. */ + + if (supported < 0) + supported = + access("/proc/swaps", F_OK) >= 0 && + detect_container() <= 0; + + return supported; +} + +static int swap_control_pid(Unit *u) { + Swap *s = SWAP(u); + + assert(s); + + return s->control_pid; +} + +static const char* const swap_exec_command_table[_SWAP_EXEC_COMMAND_MAX] = { + [SWAP_EXEC_ACTIVATE] = "ExecActivate", + [SWAP_EXEC_DEACTIVATE] = "ExecDeactivate", +}; + +DEFINE_STRING_TABLE_LOOKUP(swap_exec_command, SwapExecCommand); + +static const char* const swap_result_table[_SWAP_RESULT_MAX] = { + [SWAP_SUCCESS] = "success", + [SWAP_FAILURE_RESOURCES] = "resources", + [SWAP_FAILURE_TIMEOUT] = "timeout", + [SWAP_FAILURE_EXIT_CODE] = "exit-code", + [SWAP_FAILURE_SIGNAL] = "signal", + [SWAP_FAILURE_CORE_DUMP] = "core-dump", + [SWAP_FAILURE_START_LIMIT_HIT] = "start-limit-hit", +}; + +DEFINE_STRING_TABLE_LOOKUP(swap_result, SwapResult); + +const UnitVTable swap_vtable = { + .object_size = sizeof(Swap), + .exec_context_offset = offsetof(Swap, exec_context), + .cgroup_context_offset = offsetof(Swap, cgroup_context), + .kill_context_offset = offsetof(Swap, kill_context), + .exec_runtime_offset = offsetof(Swap, exec_runtime), + .dynamic_creds_offset = offsetof(Swap, dynamic_creds), + + .sections = + "Unit\0" + "Swap\0" + "Install\0", + .private_section = "Swap", + + .init = swap_init, + .load = swap_load, + .done = swap_done, + + .coldplug = swap_coldplug, + + .dump = swap_dump, + + .start = swap_start, + .stop = swap_stop, + + .kill = swap_kill, + + .get_timeout = swap_get_timeout, + + .serialize = swap_serialize, + .deserialize_item = swap_deserialize_item, + + .active_state = swap_active_state, + .sub_state_to_string = swap_sub_state_to_string, + + .may_gc = swap_may_gc, + + .sigchld_event = swap_sigchld_event, + + .reset_failed = swap_reset_failed, + + .control_pid = swap_control_pid, + + .bus_vtable = bus_swap_vtable, + .bus_set_property = bus_swap_set_property, + .bus_commit_properties = bus_swap_commit_properties, + + .following = swap_following, + .following_set = swap_following_set, + + .enumerate = swap_enumerate, + .shutdown = swap_shutdown, + .supported = swap_supported, + + .status_message_formats = { + .starting_stopping = { + [0] = "Activating swap %s...", + [1] = "Deactivating swap %s...", + }, + .finished_start_job = { + [JOB_DONE] = "Activated swap %s.", + [JOB_FAILED] = "Failed to activate swap %s.", + [JOB_TIMEOUT] = "Timed out activating swap %s.", + }, + .finished_stop_job = { + [JOB_DONE] = "Deactivated swap %s.", + [JOB_FAILED] = "Failed deactivating swap %s.", + [JOB_TIMEOUT] = "Timed out deactivating swap %s.", + }, + }, +}; |