From 8d567588cad053f79abe603ab113e1b85a92f1da Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Fri, 16 Apr 2010 23:24:39 +0200 Subject: automount: implement automount unit type --- automount.c | 507 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 499 insertions(+), 8 deletions(-) (limited to 'automount.c') diff --git a/automount.c b/automount.c index 1192949d83..5d79131afc 100644 --- a/automount.c +++ b/automount.c @@ -20,11 +20,20 @@ ***/ #include +#include +#include +#include +#include +#include +#include +#include +#include #include "unit.h" #include "automount.h" #include "load-fragment.h" #include "load-dropin.h" +#include "unit-name.h" static const UnitActiveState state_translation_table[_AUTOMOUNT_STATE_MAX] = { [AUTOMOUNT_DEAD] = UNIT_INACTIVE, @@ -40,11 +49,95 @@ static const char* const state_string_table[_AUTOMOUNT_STATE_MAX] = { [AUTOMOUNT_MAINTAINANCE] = "maintainance" }; +static char *automount_name_from_where(const char *where) { + assert(where); + + if (streq(where, "/")) + return strdup("-.automount"); + + return unit_name_build_escape(where+1, NULL, ".automount"); +} + static void automount_init(Unit *u) { Automount *a = AUTOMOUNT(u); - a->state = 0; + assert(u); + assert(u->meta.load_state == UNIT_STUB); + + a->pipe_watch.fd = a->pipe_fd = -1; +} + +static void repeat_unmout(const char *path) { + assert(path); + + for (;;) { + + if (umount2(path, MNT_DETACH) >= 0) + continue; + + if (errno != EINVAL) + log_error("Failed to unmount: %m"); + + break; + } +} + +static void unmount_autofs(Automount *a) { + assert(a); + + if (a->pipe_fd < 0) + return; + + automount_send_ready(a, -EHOSTDOWN); + + unit_unwatch_fd(UNIT(a), &a->pipe_watch); + close_nointr_nofail(a->pipe_fd); + a->pipe_fd = -1; + + repeat_unmout(a->where); +} + +static void automount_done(Unit *u) { + Automount *a = AUTOMOUNT(u); + + assert(a); + + unmount_autofs(a); a->mount = NULL; + + if (a->tokens) { + set_free(a->tokens); + a->tokens = NULL; + } +} + +static int automount_verify(Automount *a) { + bool b; + char *e; + assert(a); + + if (UNIT(a)->meta.load_state != UNIT_LOADED) + return 0; + + if (!a->where) { + log_error("%s lacks Where setting. Refusing.", UNIT(a)->meta.id); + return -EINVAL; + } + + path_kill_slashes(a->where); + + if (!(e = automount_name_from_where(a->where))) + return -ENOMEM; + + b = unit_has_name(UNIT(a), e); + free(e); + + if (!b) { + log_error("%s's Where setting doesn't match unit name. Refusing.", UNIT(a)->meta.id); + return -EINVAL; + } + + return 0; } static int automount_load(Unit *u) { @@ -67,15 +160,24 @@ static int automount_load(Unit *u) { return r; } - return 0; + return automount_verify(a); } -static void automount_done(Unit *u) { - Automount *a = AUTOMOUNT(u); - +static void automount_set_state(Automount *a, AutomountState state) { + AutomountState old_state; assert(a); - a->mount = NULL; + old_state = a->state; + a->state = state; + + if (state != AUTOMOUNT_WAITING && + state != AUTOMOUNT_RUNNING) + unmount_autofs(a); + + if (state != old_state) + log_debug("%s changed %s → %s", UNIT(a)->meta.id, state_string_table[old_state], state_string_table[state]); + + unit_notify(UNIT(a), state_translation_table[old_state], state_translation_table[state]); } static void automount_dump(Unit *u, FILE *f, const char *prefix) { @@ -88,6 +190,336 @@ static void automount_dump(Unit *u, FILE *f, const char *prefix) { prefix, state_string_table[s->state]); } +static void automount_enter_dead(Automount *a, bool success) { + assert(a); + + if (!success) + a->failure = true; + + automount_set_state(a, a->failure ? AUTOMOUNT_MAINTAINANCE : AUTOMOUNT_DEAD); +} + +static int open_dev_autofs(Manager *m) { + struct autofs_dev_ioctl param; + + assert(m); + + if (m->dev_autofs_fd >= 0) + return m->dev_autofs_fd; + + if ((m->dev_autofs_fd = open("/dev/autofs", O_RDONLY)) < 0) { + log_error("Failed to open /dev/autofs: %s", strerror(errno)); + return -errno; + } + + init_autofs_dev_ioctl(¶m); + if (ioctl(m->dev_autofs_fd, AUTOFS_DEV_IOCTL_VERSION, ¶m) < 0) { + close_nointr_nofail(m->dev_autofs_fd); + m->dev_autofs_fd = -1; + return -errno; + } + + log_debug("Autofs kernel version %i.%i", param.ver_major, param.ver_minor); + + return m->dev_autofs_fd; +} + +static int open_ioctl_fd(int dev_autofs_fd, const char *where, dev_t devid) { + struct autofs_dev_ioctl *param; + size_t l; + int r; + + assert(dev_autofs_fd >= 0); + assert(where); + + l = sizeof(struct autofs_dev_ioctl) + strlen(where) + 1; + + if (!(param = malloc(l))) + return -ENOMEM; + + init_autofs_dev_ioctl(param); + param->size = l; + param->ioctlfd = -1; + param->openmount.devid = devid; + strcpy(param->path, where); + + if (ioctl(dev_autofs_fd, AUTOFS_DEV_IOCTL_OPENMOUNT, param) < 0) { + r = -errno; + goto finish; + } + + if (param->ioctlfd < 0) { + r = -EIO; + goto finish; + } + + r = param->ioctlfd; + +finish: + free(param); + return r; +} + +static int autofs_protocol(int dev_autofs_fd, int ioctl_fd) { + uint32_t major, minor; + struct autofs_dev_ioctl param; + + assert(dev_autofs_fd >= 0); + assert(ioctl_fd >= 0); + + init_autofs_dev_ioctl(¶m); + param.ioctlfd = ioctl_fd; + + if (ioctl(dev_autofs_fd, AUTOFS_DEV_IOCTL_PROTOVER, ¶m) < 0) + return -errno; + + major = param.protover.version; + + init_autofs_dev_ioctl(¶m); + param.ioctlfd = ioctl_fd; + + if (ioctl(dev_autofs_fd, AUTOFS_DEV_IOCTL_PROTOSUBVER, ¶m) < 0) + return -errno; + + minor = param.protosubver.sub_version; + + log_debug("Autofs protocol version %i.%i", major, minor); + return 0; +} + +static int autofs_set_timeout(int dev_autofs_fd, int ioctl_fd, time_t sec) { + struct autofs_dev_ioctl param; + + assert(dev_autofs_fd >= 0); + assert(ioctl_fd >= 0); + + init_autofs_dev_ioctl(¶m); + param.ioctlfd = ioctl_fd; + param.timeout.timeout = sec; + + if (ioctl(dev_autofs_fd, AUTOFS_DEV_IOCTL_TIMEOUT, ¶m) < 0) + return -errno; + + return 0; +} + +static int autofs_send_ready(int dev_autofs_fd, int ioctl_fd, uint32_t token, int status) { + struct autofs_dev_ioctl param; + + assert(dev_autofs_fd >= 0); + assert(ioctl_fd >= 0); + + init_autofs_dev_ioctl(¶m); + param.ioctlfd = ioctl_fd; + + if (status) { + param.fail.token = token; + param.fail.status = status; + } else + param.ready.token = token; + + if (ioctl(dev_autofs_fd, status ? AUTOFS_DEV_IOCTL_FAIL : AUTOFS_DEV_IOCTL_READY, ¶m) < 0) + return -errno; + + return 0; +} + +int automount_send_ready(Automount *a, int status) { + int ioctl_fd, r; + unsigned token; + + assert(a); + assert(status <= 0); + + if (set_isempty(a->tokens)) + return 0; + + if ((ioctl_fd = open_ioctl_fd(UNIT(a)->meta.manager->dev_autofs_fd, a->where, a->dev_id)) < 0) { + r = ioctl_fd; + goto fail; + } + + if (status) + log_debug("Sending failure: %s", strerror(-status)); + else + log_debug("Sending success."); + + /* Autofs thankfully does not hand out 0 as a token */ + while ((token = PTR_TO_UINT(set_steal_first(a->tokens)))) { + int k; + + /* Autofs fun fact II: + * + * if you pass a positive status code here, the kernel will + * freeze! Yay! */ + + if ((k = autofs_send_ready(UNIT(a)->meta.manager->dev_autofs_fd, + ioctl_fd, + token, + status)) < 0) + r = k; + } + + r = 0; + +fail: + if (ioctl_fd >= 0) + close_nointr_nofail(ioctl_fd); + + return r; +} + +static void automount_enter_waiting(Automount *a) { + int p[2] = { -1, -1 }; + char name[32], options[128]; + bool mounted = false; + int r, ioctl_fd = -1, dev_autofs_fd; + struct stat st; + + assert(a); + assert(a->pipe_fd < 0); + assert(a->where); + + if (a->tokens) + set_clear(a->tokens); + else if (!(a->tokens = set_new(trivial_hash_func, trivial_compare_func))) { + r = -ENOMEM; + goto fail; + } + + if ((dev_autofs_fd = open_dev_autofs(UNIT(a)->meta.manager)) < 0) { + r = dev_autofs_fd; + goto fail; + } + + /* We knowingly ignore the results of this call */ + mkdir_p(a->where, 0555); + + if (pipe2(p, O_NONBLOCK) < 0) { + r = -errno; + goto fail; + } + + snprintf(options, sizeof(options), "fd=%i,pgrp=%u,minproto=5,maxproto=5,direct", p[1], (unsigned) getpgrp()); + char_array_0(options); + + snprintf(name, sizeof(name), "systemd-%u", (unsigned) getpid()); + char_array_0(name); + + if (mount(name, a->where, "autofs", 0, options) < 0) { + r = -errno; + goto fail; + } + + mounted = true; + + close_nointr_nofail(p[1]); + p[1] = -1; + + if (stat(a->where, &st) < 0) { + r = -errno; + goto fail; + } + + if ((ioctl_fd = open_ioctl_fd(dev_autofs_fd, a->where, st.st_dev)) < 0) { + r = ioctl_fd; + goto fail; + } + + if ((r = autofs_protocol(dev_autofs_fd, ioctl_fd)) < 0) + goto fail; + + if ((r = autofs_set_timeout(dev_autofs_fd, ioctl_fd, 300)) < 0) + goto fail; + + /* Autofs fun fact: + * + * Unless we close the ioctl fd here, for some weird reason + * the direct mount will not receive events from the + * kernel. */ + + close_nointr_nofail(ioctl_fd); + ioctl_fd = -1; + + if ((r = unit_watch_fd(UNIT(a), p[0], EPOLLIN, &a->pipe_watch)) < 0) + goto fail; + + a->pipe_fd = p[0]; + a->dev_id = st.st_dev; + + automount_set_state(a, AUTOMOUNT_WAITING); + + return; + +fail: + assert_se(close_pipe(p) == 0); + + if (ioctl_fd >= 0) + close_nointr_nofail(ioctl_fd); + + if (mounted) + repeat_unmout(a->where); + + log_error("Failed to initialize automounter: %s", strerror(-r)); + automount_enter_dead(a, false); +} + +static void automount_enter_runnning(Automount *a) { + int r; + struct stat st; + + assert(a); + assert(a->mount); + + /* Before we do anything, let's see if somebody is playing games with us? */ + + if (stat(a->where, &st) < 0) { + log_warning("%s failed stat automount point: %m", a->meta.id); + goto fail; + } + + if (!S_ISDIR(st.st_mode) || st.st_dev != a->dev_id) + log_info("%s's automount point already active?", a->meta.id); + else if ((r = manager_add_job(UNIT(a)->meta.manager, JOB_START, UNIT(a->mount), JOB_REPLACE, true, NULL)) < 0) { + log_warning("%s failed to queue mount startup job: %s", a->meta.id, strerror(-r)); + goto fail; + } + + automount_set_state(a, AUTOMOUNT_RUNNING); + return; + +fail: + automount_enter_dead(a, false); +} + +static int automount_start(Unit *u) { + Automount *a = AUTOMOUNT(u); + + assert(a); + + if (path_is_mount_point(a->where)) { + log_error("Path %s is already a mount point, refusing start for %s", a->where, u->meta.id); + return -EEXIST; + } + + assert(a->state == AUTOMOUNT_DEAD || a->state == AUTOMOUNT_MAINTAINANCE); + + a->failure = false; + automount_enter_waiting(a); + return 0; +} + +static int automount_stop(Unit *u) { + Automount *a = AUTOMOUNT(u); + + assert(a); + + assert(a->state == AUTOMOUNT_WAITING || a->state == AUTOMOUNT_RUNNING); + + automount_enter_dead(a, true); + return 0; +} + static UnitActiveState automount_active_state(Unit *u) { return state_translation_table[AUTOMOUNT(u)->state]; @@ -99,10 +531,62 @@ static const char *automount_sub_state_to_string(Unit *u) { return state_string_table[AUTOMOUNT(u)->state]; } +static void automount_fd_event(Unit *u, int fd, uint32_t events, Watch *w) { + union autofs_v5_packet_union packet; + ssize_t l; + int r; + + Automount *a = AUTOMOUNT(u); + + assert(a); + assert(fd == a->pipe_fd); + + if (events != EPOLLIN) { + log_error("Got invalid poll event on pipe."); + goto fail; + } + + if ((l = loop_read(a->pipe_fd, &packet, sizeof(packet))) != sizeof(packet)) { + log_error("Invalid read from pipe: %s", l < 0 ? strerror(-l) : "short read"); + goto fail; + } + + switch (packet.hdr.type) { + + case autofs_ptype_missing_direct: + log_debug("Got direct mount request for %s", packet.v5_packet.name); + + if ((r = set_put(a->tokens, UINT_TO_PTR(packet.v5_packet.wait_queue_token))) < 0) { + log_error("Failed to remember token: %s", strerror(-r)); + goto fail; + } + + automount_enter_runnning(a); + break; + + default: + log_error("Received unknown automount request %i", packet.hdr.type); + break; + } + + return; + +fail: + automount_enter_dead(a, false); +} + +static void automount_shutdown(Manager *m) { + assert(m); + + if (m->dev_autofs_fd >= 0) + close_nointr_nofail(m->dev_autofs_fd); +} + const UnitVTable automount_vtable = { - .suffix = ".mount", + .suffix = ".automount", .no_alias = true, + .no_instances = true, .init = automount_init, .load = automount_load, @@ -110,6 +594,13 @@ const UnitVTable automount_vtable = { .dump = automount_dump, + .start = automount_start, + .stop = automount_stop, + .active_state = automount_active_state, - .sub_state_to_string = automount_sub_state_to_string + .sub_state_to_string = automount_sub_state_to_string, + + .fd_event = automount_fd_event, + + .shutdown = automount_shutdown }; -- cgit v1.2.3-54-g00ecf