diff options
Diffstat (limited to 'swap.c')
| -rw-r--r-- | swap.c | 424 |
1 files changed, 424 insertions, 0 deletions
diff --git a/swap.c b/swap.c new file mode 100644 index 0000000000..aacf0e8d55 --- /dev/null +++ b/swap.c @@ -0,0 +1,424 @@ +/*-*- Mode: C; c-basic-offset: 8 -*-*/ + +/*** + This file is part of systemd. + + Copyright 2010 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <errno.h> +#include <limits.h> +#include <unistd.h> +#include <fcntl.h> +#include <sys/epoll.h> +#include <sys/stat.h> +#include <sys/swap.h> + +#include "unit.h" +#include "swap.h" +#include "load-fragment.h" +#include "load-dropin.h" +#include "unit-name.h" +#include "dbus-swap.h" + +static const UnitActiveState state_translation_table[_SWAP_STATE_MAX] = { + [SWAP_DEAD] = UNIT_INACTIVE, + [SWAP_ACTIVE] = UNIT_ACTIVE, + [SWAP_MAINTAINANCE] = UNIT_INACTIVE +}; + +static int swap_verify(Swap *s) { + bool b; + char *e; + + if (UNIT(s)->meta.load_state != UNIT_LOADED) + return 0; + + if (!(e = unit_name_from_path(s->what, ".swap"))) + return -ENOMEM; + + b = unit_has_name(UNIT(s), e); + free(e); + + if (!b) { + log_error("%s: Value of \"What\" and unit name do not match, not loading.\n", UNIT(s)->meta.id); + return -EINVAL; + } + return 0; +} + +static int swap_add_target_links(Swap *s) { + Manager *m = s->meta.manager; + Unit *tu; + int r; + + r = manager_load_unit(m, SPECIAL_SWAP_TARGET, NULL, &tu); + if (r < 0) + return r; + + if (!s->no_auto && (r = unit_add_dependency(tu, UNIT_WANTS, UNIT(s), true)) < 0) + return r; + + return unit_add_dependency(UNIT(s), UNIT_BEFORE, tu, true); +} + +static int swap_load(Unit *u) { + int r; + Swap *s = SWAP(u); + + assert(s); + assert(u->meta.load_state == UNIT_STUB); + + /* Load a .swap file */ + if ((r = unit_load_fragment_and_dropin_optional(u)) < 0) + return r; + + if (u->meta.load_state == UNIT_LOADED) { + if (!s->what) + if (!(s->what = unit_name_to_path(u->meta.id))) + return -ENOMEM; + + path_kill_slashes(s->what); + + if ((r = mount_add_node_links(u, s->what)) < 0) + return r; + + if (!path_startswith(s->what, "/dev/")) + if ((r = mount_add_path_links(u, s->what, true)) < 0) + return r; + + if ((r = swap_add_target_links(s)) < 0) + return r; + } + + return swap_verify(s); +} + +int swap_add_one(Manager *m, const char *what, bool no_auto, int prio, bool from_proc_swaps) { + Unit *u; + char *e; + bool delete; + int r; + + if (!(e = unit_name_from_path(what, ".swap"))) + return -ENOMEM; + + if (!(u = manager_get_unit(m, e))) { + delete = true; + + if (!(u = unit_new(m))) { + free(e); + return -ENOMEM; + } + + r = unit_add_name(u, e); + free(e); + + if (r < 0) + goto fail; + + if (!(SWAP(u)->what = strdup(what))) { + r = -ENOMEM; + goto fail; + } + + if ((r = unit_set_description(u, what)) < 0) + goto fail; + + unit_add_to_load_queue(u); + + SWAP(u)->from_proc_swaps_only = from_proc_swaps; + } else { + if (SWAP(u)->from_proc_swaps_only && !from_proc_swaps) + SWAP(u)->from_proc_swaps_only = false; + + delete = false; + free(e); + } + + if (!from_proc_swaps) + SWAP(u)->no_auto = no_auto; + else + SWAP(u)->found_in_proc_swaps = true; + + SWAP(u)->priority = prio; + + return 0; + +fail: + if (delete) + unit_free(u); + + return 0; +} + +static void swap_set_state(Swap *s, SwapState state) { + SwapState old_state; + assert(s); + + old_state = s->state; + s->state = state; + + if (state != old_state) + log_debug("%s changed %s -> %s", + UNIT(s)->meta.id, + swap_state_to_string(old_state), + swap_state_to_string(state)); + + unit_notify(UNIT(s), state_translation_table[old_state], state_translation_table[state]); +} + +static int swap_coldplug(Unit *u) { + Swap *s = SWAP(u); + SwapState new_state = SWAP_DEAD; + + assert(s); + assert(s->state == SWAP_DEAD); + + if (s->deserialized_state != s->state) + new_state = s->deserialized_state; + else if (s->found_in_proc_swaps) + new_state = SWAP_ACTIVE; + + if (new_state != s->state) + swap_set_state(s, s->deserialized_state); + + return 0; +} + +static void swap_dump(Unit *u, FILE *f, const char *prefix) { + Swap *s = SWAP(u); + + assert(s); + + fprintf(f, + "%sAutomount State: %s\n" + "%sWhat: %s\n" + "%sPriority: %i\n" + "%sNoAuto: %s\n", + prefix, swap_state_to_string(s->state), + prefix, s->what, + prefix, s->priority, + prefix, yes_no(s->no_auto)); +} + +static void swap_enter_dead(Swap *s, bool success) { + assert(s); + + swap_set_state(s, success ? SWAP_MAINTAINANCE : SWAP_DEAD); +} + +static int swap_start(Unit *u) { + Swap *s = SWAP(u); + int r; + + assert(s); + + assert(s->state == SWAP_DEAD || s->state == SWAP_MAINTAINANCE); + + r = swapon(s->what, (s->priority << SWAP_FLAG_PRIO_SHIFT) & SWAP_FLAG_PRIO_MASK); + + if (r < 0 && errno != EBUSY) { + r = -errno; + swap_enter_dead(s, false); + return r; + } + + swap_set_state(s, SWAP_ACTIVE); + return 0; +} + +static int swap_stop(Unit *u) { + Swap *s = SWAP(u); + int r; + + assert(s); + + assert(s->state == SWAP_ACTIVE); + + r = swapoff(s->what); + swap_enter_dead(s, r >= 0 || errno == EINVAL); + + return 0; +} + +static int swap_serialize(Unit *u, FILE *f, FDSet *fds) { + Swap *s = SWAP(u); + + assert(s); + assert(f); + assert(fds); + + unit_serialize_item(u, f, "state", swap_state_to_string(s->state)); + + 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; + + if ((state = swap_state_from_string(value)) < 0) + log_debug("Failed to parse state value %s", value); + else + s->deserialized_state = state; + } else + log_debug("Unknown serialization key '%s'", key); + + return 0; +} + +static UnitActiveState swap_active_state(Unit *u) { + assert(u); + + return state_translation_table[SWAP(u)->state]; +} + +static const char *swap_sub_state_to_string(Unit *u) { + assert(u); + + return swap_state_to_string(SWAP(u)->state); +} + +static bool swap_check_gc(Unit *u) { + Swap *s = SWAP(u); + + assert(s); + + return !s->from_proc_swaps_only || s->found_in_proc_swaps; +} + +static int swap_load_proc_swaps(Manager *m) { + Meta *meta; + + rewind(m->proc_swaps); + fscanf(m->proc_self_mountinfo, "%*s %*s %*s %*s %*s\n"); + + for (;;) { + char *dev = NULL, *d; + int prio = 0, k; + + k = fscanf(m->proc_self_mountinfo, + "%ms " /* device/file */ + "%*s " /* type of swap */ + "%*s " /* swap size */ + "%*s " /* used */ + "%d\n", /* priority */ + &dev, &prio); + + if (k != 2) { + if (k == EOF) + k = 0; + + free(dev); + return -EBADMSG; + } + if (!(d = cunescape(dev))) { + free(dev); + k = -ENOMEM; + return k; + } + + k = swap_add_one(m, d, false, prio, true); + free(dev); + free(d); + + if (k < 0) + return k; + } + + LIST_FOREACH(units_per_type, meta, m->units_per_type[UNIT_SWAP]) { + Swap *s = (Swap*) meta; + + if (s->state != SWAP_DEAD && s->state != SWAP_ACTIVE) + continue; + + if ((s->state == SWAP_DEAD && !s->found_in_proc_swaps) || + (s->state == SWAP_ACTIVE && s->found_in_proc_swaps)) + continue; + + swap_set_state(s, s->found_in_proc_swaps ? SWAP_ACTIVE : SWAP_DEAD); + + /* Reset the flags for later calls */ + s->found_in_proc_swaps = false; + } +} + +static void swap_shutdown(Manager *m) { + assert(m); + + if (m->proc_swaps) { + fclose(m->proc_swaps); + m->proc_swaps = NULL; + } +} + +static const char* const swap_state_table[_SWAP_STATE_MAX] = { + [SWAP_DEAD] = "dead", + [SWAP_ACTIVE] = "active", + [SWAP_MAINTAINANCE] = "maintainance" +}; + +DEFINE_STRING_TABLE_LOOKUP(swap_state, SwapState); + +static int swap_enumerate(Manager *m) { + int r; + assert(m); + + if (!m->proc_swaps && + !(m->proc_swaps = fopen("/proc/swaps", "er"))) + return -errno; + + if ((r = swap_load_proc_swaps(m)) < 0) + swap_shutdown(m); + + return r; +} + +const UnitVTable swap_vtable = { + .suffix = ".swap", + + .no_alias = true, + .no_instances = true, + + .load = swap_load, + + .coldplug = swap_coldplug, + + .dump = swap_dump, + + .start = swap_start, + .stop = swap_stop, + + .serialize = swap_serialize, + .deserialize_item = swap_deserialize_item, + + .active_state = swap_active_state, + .sub_state_to_string = swap_sub_state_to_string, + + .check_gc = swap_check_gc, + + .bus_message_handler = bus_swap_message_handler, + + .shutdown = swap_shutdown, + + .enumerate = swap_enumerate +}; |