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-rw-r--r--src/login/logind-seat.c664
1 files changed, 664 insertions, 0 deletions
diff --git a/src/login/logind-seat.c b/src/login/logind-seat.c
new file mode 100644
index 0000000..10cc7d9
--- /dev/null
+++ b/src/login/logind-seat.c
@@ -0,0 +1,664 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "sd-messages.h"
+
+#include "alloc-util.h"
+#include "errno-util.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "format-util.h"
+#include "logind-acl.h"
+#include "logind-seat-dbus.h"
+#include "logind-seat.h"
+#include "logind-session-dbus.h"
+#include "mkdir.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "stdio-util.h"
+#include "string-util.h"
+#include "terminal-util.h"
+#include "tmpfile-util.h"
+#include "util.h"
+
+int seat_new(Seat** ret, Manager *m, const char *id) {
+ _cleanup_(seat_freep) Seat *s = NULL;
+ int r;
+
+ assert(ret);
+ assert(m);
+ assert(id);
+
+ if (!seat_name_is_valid(id))
+ return -EINVAL;
+
+ s = new(Seat, 1);
+ if (!s)
+ return -ENOMEM;
+
+ *s = (Seat) {
+ .manager = m,
+ };
+
+ s->state_file = path_join("/run/systemd/seats", id);
+ if (!s->state_file)
+ return -ENOMEM;
+
+ s->id = basename(s->state_file);
+
+ r = hashmap_put(m->seats, s->id, s);
+ if (r < 0)
+ return r;
+
+ *ret = TAKE_PTR(s);
+ return 0;
+}
+
+Seat* seat_free(Seat *s) {
+ if (!s)
+ return NULL;
+
+ if (s->in_gc_queue)
+ LIST_REMOVE(gc_queue, s->manager->seat_gc_queue, s);
+
+ while (s->sessions)
+ session_free(s->sessions);
+
+ assert(!s->active);
+
+ while (s->devices)
+ device_free(s->devices);
+
+ hashmap_remove(s->manager->seats, s->id);
+
+ free(s->positions);
+ free(s->state_file);
+
+ return mfree(s);
+}
+
+int seat_save(Seat *s) {
+ _cleanup_free_ char *temp_path = NULL;
+ _cleanup_fclose_ FILE *f = NULL;
+ int r;
+
+ assert(s);
+
+ if (!s->started)
+ return 0;
+
+ r = mkdir_safe_label("/run/systemd/seats", 0755, 0, 0, MKDIR_WARN_MODE);
+ if (r < 0)
+ goto fail;
+
+ r = fopen_temporary(s->state_file, &f, &temp_path);
+ if (r < 0)
+ goto fail;
+
+ (void) fchmod(fileno(f), 0644);
+
+ fprintf(f,
+ "# This is private data. Do not parse.\n"
+ "IS_SEAT0=%i\n"
+ "CAN_MULTI_SESSION=1\n"
+ "CAN_TTY=%i\n"
+ "CAN_GRAPHICAL=%i\n",
+ seat_is_seat0(s),
+ seat_can_tty(s),
+ seat_can_graphical(s));
+
+ if (s->active) {
+ assert(s->active->user);
+
+ fprintf(f,
+ "ACTIVE=%s\n"
+ "ACTIVE_UID="UID_FMT"\n",
+ s->active->id,
+ s->active->user->user_record->uid);
+ }
+
+ if (s->sessions) {
+ Session *i;
+
+ fputs("SESSIONS=", f);
+ LIST_FOREACH(sessions_by_seat, i, s->sessions) {
+ fprintf(f,
+ "%s%c",
+ i->id,
+ i->sessions_by_seat_next ? ' ' : '\n');
+ }
+
+ fputs("UIDS=", f);
+ LIST_FOREACH(sessions_by_seat, i, s->sessions)
+ fprintf(f,
+ UID_FMT"%c",
+ i->user->user_record->uid,
+ i->sessions_by_seat_next ? ' ' : '\n');
+ }
+
+ r = fflush_and_check(f);
+ if (r < 0)
+ goto fail;
+
+ if (rename(temp_path, s->state_file) < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ return 0;
+
+fail:
+ (void) unlink(s->state_file);
+
+ if (temp_path)
+ (void) unlink(temp_path);
+
+ return log_error_errno(r, "Failed to save seat data %s: %m", s->state_file);
+}
+
+int seat_load(Seat *s) {
+ assert(s);
+
+ /* There isn't actually anything to read here ... */
+
+ return 0;
+}
+
+static int vt_allocate(unsigned vtnr) {
+ char p[sizeof("/dev/tty") + DECIMAL_STR_MAX(unsigned)];
+ _cleanup_close_ int fd = -1;
+
+ assert(vtnr >= 1);
+
+ xsprintf(p, "/dev/tty%u", vtnr);
+ fd = open_terminal(p, O_RDWR|O_NOCTTY|O_CLOEXEC);
+ if (fd < 0)
+ return fd;
+
+ return 0;
+}
+
+int seat_preallocate_vts(Seat *s) {
+ int r = 0;
+ unsigned i;
+
+ assert(s);
+ assert(s->manager);
+
+ if (s->manager->n_autovts <= 0)
+ return 0;
+
+ if (!seat_has_vts(s))
+ return 0;
+
+ log_debug("Preallocating VTs...");
+
+ for (i = 1; i <= s->manager->n_autovts; i++) {
+ int q;
+
+ q = vt_allocate(i);
+ if (q < 0)
+ r = log_error_errno(q, "Failed to preallocate VT %u: %m", i);
+ }
+
+ return r;
+}
+
+int seat_apply_acls(Seat *s, Session *old_active) {
+ int r;
+
+ assert(s);
+
+ r = devnode_acl_all(s->id,
+ false,
+ !!old_active, old_active ? old_active->user->user_record->uid : 0,
+ !!s->active, s->active ? s->active->user->user_record->uid : 0);
+
+ if (r < 0)
+ return log_error_errno(r, "Failed to apply ACLs: %m");
+
+ return 0;
+}
+
+int seat_set_active(Seat *s, Session *session) {
+ Session *old_active;
+
+ assert(s);
+ assert(!session || session->seat == s);
+
+ if (session == s->active)
+ return 0;
+
+ old_active = s->active;
+ s->active = session;
+
+ if (old_active) {
+ session_device_pause_all(old_active);
+ session_send_changed(old_active, "Active", NULL);
+ }
+
+ (void) seat_apply_acls(s, old_active);
+
+ if (session && session->started) {
+ session_send_changed(session, "Active", NULL);
+ session_device_resume_all(session);
+ }
+
+ if (!session || session->started)
+ seat_send_changed(s, "ActiveSession", NULL);
+
+ seat_save(s);
+
+ if (session) {
+ session_save(session);
+ user_save(session->user);
+ }
+
+ if (old_active) {
+ session_save(old_active);
+ if (!session || session->user != old_active->user)
+ user_save(old_active->user);
+ }
+
+ return 0;
+}
+
+int seat_switch_to(Seat *s, unsigned num) {
+ /* Public session positions skip 0 (there is only F1-F12). Maybe it
+ * will get reassigned in the future, so return error for now. */
+ if (num == 0)
+ return -EINVAL;
+
+ if (num >= s->position_count || !s->positions[num]) {
+ /* allow switching to unused VTs to trigger auto-activate */
+ if (seat_has_vts(s) && num < 64)
+ return chvt(num);
+
+ return -EINVAL;
+ }
+
+ return session_activate(s->positions[num]);
+}
+
+int seat_switch_to_next(Seat *s) {
+ unsigned start, i;
+
+ if (s->position_count == 0)
+ return -EINVAL;
+
+ start = 1;
+ if (s->active && s->active->position > 0)
+ start = s->active->position;
+
+ for (i = start + 1; i < s->position_count; ++i)
+ if (s->positions[i])
+ return session_activate(s->positions[i]);
+
+ for (i = 1; i < start; ++i)
+ if (s->positions[i])
+ return session_activate(s->positions[i]);
+
+ return -EINVAL;
+}
+
+int seat_switch_to_previous(Seat *s) {
+ unsigned start, i;
+
+ if (s->position_count == 0)
+ return -EINVAL;
+
+ start = 1;
+ if (s->active && s->active->position > 0)
+ start = s->active->position;
+
+ for (i = start - 1; i > 0; --i)
+ if (s->positions[i])
+ return session_activate(s->positions[i]);
+
+ for (i = s->position_count - 1; i > start; --i)
+ if (s->positions[i])
+ return session_activate(s->positions[i]);
+
+ return -EINVAL;
+}
+
+int seat_active_vt_changed(Seat *s, unsigned vtnr) {
+ Session *i, *new_active = NULL;
+ int r;
+
+ assert(s);
+ assert(vtnr >= 1);
+
+ if (!seat_has_vts(s))
+ return -EINVAL;
+
+ log_debug("VT changed to %u", vtnr);
+
+ /* we might have earlier closing sessions on the same VT, so try to
+ * find a running one first */
+ LIST_FOREACH(sessions_by_seat, i, s->sessions)
+ if (i->vtnr == vtnr && !i->stopping) {
+ new_active = i;
+ break;
+ }
+
+ if (!new_active) {
+ /* no running one? then we can't decide which one is the
+ * active one, let the first one win */
+ LIST_FOREACH(sessions_by_seat, i, s->sessions)
+ if (i->vtnr == vtnr) {
+ new_active = i;
+ break;
+ }
+ }
+
+ r = seat_set_active(s, new_active);
+ manager_spawn_autovt(s->manager, vtnr);
+
+ return r;
+}
+
+int seat_read_active_vt(Seat *s) {
+ char t[64];
+ ssize_t k;
+ int vtnr;
+
+ assert(s);
+
+ if (!seat_has_vts(s))
+ return 0;
+
+ if (lseek(s->manager->console_active_fd, SEEK_SET, 0) < 0)
+ return log_error_errno(errno, "lseek on console_active_fd failed: %m");
+
+ k = read(s->manager->console_active_fd, t, sizeof(t)-1);
+ if (k <= 0) {
+ log_error("Failed to read current console: %s", k < 0 ? strerror_safe(errno) : "EOF");
+ return k < 0 ? -errno : -EIO;
+ }
+
+ t[k] = 0;
+ truncate_nl(t);
+
+ vtnr = vtnr_from_tty(t);
+ if (vtnr < 0) {
+ log_error_errno(vtnr, "Hm, /sys/class/tty/tty0/active is badly formatted: %m");
+ return -EIO;
+ }
+
+ return seat_active_vt_changed(s, vtnr);
+}
+
+int seat_start(Seat *s) {
+ assert(s);
+
+ if (s->started)
+ return 0;
+
+ log_struct(LOG_INFO,
+ "MESSAGE_ID=" SD_MESSAGE_SEAT_START_STR,
+ "SEAT_ID=%s", s->id,
+ LOG_MESSAGE("New seat %s.", s->id));
+
+ /* Initialize VT magic stuff */
+ seat_preallocate_vts(s);
+
+ /* Read current VT */
+ seat_read_active_vt(s);
+
+ s->started = true;
+
+ /* Save seat data */
+ seat_save(s);
+
+ seat_send_signal(s, true);
+
+ return 0;
+}
+
+int seat_stop(Seat *s, bool force) {
+ int r;
+
+ assert(s);
+
+ if (s->started)
+ log_struct(LOG_INFO,
+ "MESSAGE_ID=" SD_MESSAGE_SEAT_STOP_STR,
+ "SEAT_ID=%s", s->id,
+ LOG_MESSAGE("Removed seat %s.", s->id));
+
+ r = seat_stop_sessions(s, force);
+
+ (void) unlink(s->state_file);
+ seat_add_to_gc_queue(s);
+
+ if (s->started)
+ seat_send_signal(s, false);
+
+ s->started = false;
+
+ return r;
+}
+
+int seat_stop_sessions(Seat *s, bool force) {
+ Session *session;
+ int r = 0, k;
+
+ assert(s);
+
+ LIST_FOREACH(sessions_by_seat, session, s->sessions) {
+ k = session_stop(session, force);
+ if (k < 0)
+ r = k;
+ }
+
+ return r;
+}
+
+void seat_evict_position(Seat *s, Session *session) {
+ Session *iter;
+ unsigned pos = session->position;
+
+ session->position = 0;
+
+ if (pos == 0)
+ return;
+
+ if (pos < s->position_count && s->positions[pos] == session) {
+ s->positions[pos] = NULL;
+
+ /* There might be another session claiming the same
+ * position (eg., during gdm->session transition), so let's look
+ * for it and set it on the free slot. */
+ LIST_FOREACH(sessions_by_seat, iter, s->sessions) {
+ if (iter->position == pos && session_get_state(iter) != SESSION_CLOSING) {
+ s->positions[pos] = iter;
+ break;
+ }
+ }
+ }
+}
+
+void seat_claim_position(Seat *s, Session *session, unsigned pos) {
+ /* with VTs, the position is always the same as the VTnr */
+ if (seat_has_vts(s))
+ pos = session->vtnr;
+
+ if (!GREEDY_REALLOC0(s->positions, s->position_count, pos + 1))
+ return;
+
+ seat_evict_position(s, session);
+
+ session->position = pos;
+ if (pos > 0)
+ s->positions[pos] = session;
+}
+
+static void seat_assign_position(Seat *s, Session *session) {
+ unsigned pos;
+
+ if (session->position > 0)
+ return;
+
+ for (pos = 1; pos < s->position_count; ++pos)
+ if (!s->positions[pos])
+ break;
+
+ seat_claim_position(s, session, pos);
+}
+
+int seat_attach_session(Seat *s, Session *session) {
+ assert(s);
+ assert(session);
+ assert(!session->seat);
+
+ if (!seat_has_vts(s) != !session->vtnr)
+ return -EINVAL;
+
+ session->seat = s;
+ LIST_PREPEND(sessions_by_seat, s->sessions, session);
+ seat_assign_position(s, session);
+
+ /* On seats with VTs, the VT logic defines which session is active. On
+ * seats without VTs, we automatically activate new sessions. */
+ if (!seat_has_vts(s))
+ seat_set_active(s, session);
+
+ return 0;
+}
+
+void seat_complete_switch(Seat *s) {
+ Session *session;
+
+ assert(s);
+
+ /* if no session-switch is pending or if it got canceled, do nothing */
+ if (!s->pending_switch)
+ return;
+
+ session = TAKE_PTR(s->pending_switch);
+
+ seat_set_active(s, session);
+}
+
+bool seat_has_vts(Seat *s) {
+ assert(s);
+
+ return seat_is_seat0(s) && s->manager->console_active_fd >= 0;
+}
+
+bool seat_is_seat0(Seat *s) {
+ assert(s);
+
+ return s->manager->seat0 == s;
+}
+
+bool seat_can_tty(Seat *s) {
+ assert(s);
+
+ return seat_has_vts(s);
+}
+
+bool seat_has_master_device(Seat *s) {
+ assert(s);
+
+ /* device list is ordered by "master" flag */
+ return !!s->devices && s->devices->master;
+}
+
+bool seat_can_graphical(Seat *s) {
+ assert(s);
+
+ return seat_has_master_device(s);
+}
+
+int seat_get_idle_hint(Seat *s, dual_timestamp *t) {
+ Session *session;
+ bool idle_hint = true;
+ dual_timestamp ts = DUAL_TIMESTAMP_NULL;
+
+ assert(s);
+
+ LIST_FOREACH(sessions_by_seat, session, s->sessions) {
+ dual_timestamp k;
+ int ih;
+
+ ih = session_get_idle_hint(session, &k);
+ if (ih < 0)
+ return ih;
+
+ if (!ih) {
+ if (!idle_hint) {
+ if (k.monotonic > ts.monotonic)
+ ts = k;
+ } else {
+ idle_hint = false;
+ ts = k;
+ }
+ } else if (idle_hint) {
+
+ if (k.monotonic > ts.monotonic)
+ ts = k;
+ }
+ }
+
+ if (t)
+ *t = ts;
+
+ return idle_hint;
+}
+
+bool seat_may_gc(Seat *s, bool drop_not_started) {
+ assert(s);
+
+ if (drop_not_started && !s->started)
+ return true;
+
+ if (seat_is_seat0(s))
+ return false;
+
+ return !seat_has_master_device(s);
+}
+
+void seat_add_to_gc_queue(Seat *s) {
+ assert(s);
+
+ if (s->in_gc_queue)
+ return;
+
+ LIST_PREPEND(gc_queue, s->manager->seat_gc_queue, s);
+ s->in_gc_queue = true;
+}
+
+static bool seat_name_valid_char(char c) {
+ return
+ (c >= 'a' && c <= 'z') ||
+ (c >= 'A' && c <= 'Z') ||
+ (c >= '0' && c <= '9') ||
+ IN_SET(c, '-', '_');
+}
+
+bool seat_name_is_valid(const char *name) {
+ const char *p;
+
+ assert(name);
+
+ if (!startswith(name, "seat"))
+ return false;
+
+ if (!name[4])
+ return false;
+
+ for (p = name; *p; p++)
+ if (!seat_name_valid_char(*p))
+ return false;
+
+ if (strlen(name) > 255)
+ return false;
+
+ return true;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-20 08:18:44 +0000