chiark / gitweb /
time-util: Rename and fix call of deserialize_timestamp_value()
[elogind.git] / src / login / logind-session.c
index 20161ed..ff2c95c 100644 (file)
@@ -1,5 +1,3 @@
-/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
-
 /***
   This file is part of systemd.
 
 
 #include <errno.h>
 #include <fcntl.h>
-#include <linux/vt.h>
 #include <linux/kd.h>
+#include <linux/vt.h>
 #include <signal.h>
 #include <string.h>
 #include <sys/ioctl.h>
 #include <unistd.h>
 
-#include "sd-id128.h"
 #include "sd-messages.h"
-#include "strv.h"
-#include "util.h"
-#include "mkdir.h"
-#include "path-util.h"
-#include "fileio.h"
-#include "audit.h"
-#include "bus-util.h"
+
+#include "alloc-util.h"
+#include "audit-util.h"
 #include "bus-error.h"
+#include "bus-util.h"
+#include "escape.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "formats-util.h"
+#include "io-util.h"
 #include "logind-session.h"
+#include "mkdir.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "string-table.h"
+#include "terminal-util.h"
+#include "user-util.h"
+#include "util.h"
 
-#define RELEASE_USEC (20*USEC_PER_SEC)
+// #define RELEASE_USEC (20*USEC_PER_SEC)
 
 static void session_remove_fifo(Session *s);
 
@@ -125,7 +131,9 @@ void session_free(Session *s) {
                 free(s->scope);
         }
 
+#if 0 /// elogind does not support systemd scope_jobs
         free(s->scope_job);
+#endif // 0
 
         sd_bus_message_unref(s->create_message);
 
@@ -165,11 +173,11 @@ int session_save(Session *s) {
 
         r = mkdir_safe_label("/run/systemd/sessions", 0755, 0, 0);
         if (r < 0)
-                goto finish;
+                goto fail;
 
         r = fopen_temporary(s->state_file, &f, &temp_path);
         if (r < 0)
-                goto finish;
+                goto fail;
 
         assert(s->user);
 
@@ -196,8 +204,10 @@ int session_save(Session *s) {
 
         if (s->scope)
                 fprintf(f, "SCOPE=%s\n", s->scope);
+#if 0 /// elogind does not support systemd scope_jobs
         if (s->scope_job)
                 fprintf(f, "SCOPE_JOB=%s\n", s->scope_job);
+#endif // 0
 
         if (s->fifo_path)
                 fprintf(f, "FIFO=%s\n", s->fifo_path);
@@ -217,7 +227,7 @@ int session_save(Session *s) {
                 escaped = cescape(s->remote_host);
                 if (!escaped) {
                         r = -ENOMEM;
-                        goto finish;
+                        goto fail;
                 }
 
                 fprintf(f, "REMOTE_HOST=%s\n", escaped);
@@ -229,7 +239,7 @@ int session_save(Session *s) {
                 escaped = cescape(s->remote_user);
                 if (!escaped) {
                         r = -ENOMEM;
-                        goto finish;
+                        goto fail;
                 }
 
                 fprintf(f, "REMOTE_USER=%s\n", escaped);
@@ -241,7 +251,7 @@ int session_save(Session *s) {
                 escaped = cescape(s->service);
                 if (!escaped) {
                         r = -ENOMEM;
-                        goto finish;
+                        goto fail;
                 }
 
                 fprintf(f, "SERVICE=%s\n", escaped);
@@ -254,7 +264,7 @@ int session_save(Session *s) {
                 escaped = cescape(s->desktop);
                 if (!escaped) {
                         r = -ENOMEM;
-                        goto finish;
+                        goto fail;
                 }
 
                 fprintf(f, "DESKTOP=%s\n", escaped);
@@ -264,7 +274,7 @@ int session_save(Session *s) {
                 fprintf(f, "VTNR=%u\n", s->vtnr);
 
         if (!s->vtnr)
-                fprintf(f, "POS=%u\n", s->pos);
+                fprintf(f, "POSITION=%u\n", s->position);
 
         if (s->leader > 0)
                 fprintf(f, "LEADER="PID_FMT"\n", s->leader);
@@ -282,26 +292,33 @@ int session_save(Session *s) {
         if (s->controller)
                 fprintf(f, "CONTROLLER=%s\n", s->controller);
 
-        fflush(f);
+        r = fflush_and_check(f);
+        if (r < 0)
+                goto fail;
 
-        if (ferror(f) || rename(temp_path, s->state_file) < 0) {
+        if (rename(temp_path, s->state_file) < 0) {
                 r = -errno;
-                unlink(s->state_file);
-                unlink(temp_path);
+                goto fail;
         }
 
-finish:
-        if (r < 0)
-                log_error_errno(r, "Failed to save session data %s: %m", s->state_file);
+        return 0;
 
-        return r;
+fail:
+        (void) unlink(s->state_file);
+
+        if (temp_path)
+                (void) unlink(temp_path);
+
+        return log_error_errno(r, "Failed to save session data %s: %m", s->state_file);
 }
 
+
 int session_load(Session *s) {
         _cleanup_free_ char *remote = NULL,
                 *seat = NULL,
                 *vtnr = NULL,
-                *pos = NULL,
+                *state = NULL,
+                *position = NULL,
                 *leader = NULL,
                 *type = NULL,
                 *class = NULL,
@@ -317,7 +334,9 @@ int session_load(Session *s) {
         r = parse_env_file(s->state_file, NEWLINE,
                            "REMOTE",         &remote,
                            "SCOPE",          &s->scope,
+#if 0 /// elogind does not support systemd scope_jobs
                            "SCOPE_JOB",      &s->scope_job,
+#endif // 0
                            "FIFO",           &s->fifo_path,
                            "SEAT",           &seat,
                            "TTY",            &s->tty,
@@ -327,7 +346,8 @@ int session_load(Session *s) {
                            "SERVICE",        &s->service,
                            "DESKTOP",        &s->desktop,
                            "VTNR",           &vtnr,
-                           "POS",            &pos,
+                           "STATE",          &state,
+                           "POSITION",       &position,
                            "LEADER",         &leader,
                            "TYPE",           &type,
                            "CLASS",          &class,
@@ -337,10 +357,8 @@ int session_load(Session *s) {
                            "CONTROLLER",     &controller,
                            NULL);
 
-        if (r < 0) {
-                log_error_errno(r, "Failed to read %s: %m", s->state_file);
-                return r;
-        }
+        if (r < 0)
+                return log_error_errno(r, "Failed to read %s: %m", s->state_file);
 
         if (!s->user) {
                 uid_t u;
@@ -357,7 +375,7 @@ int session_load(Session *s) {
                         return r;
                 }
 
-                user = hashmap_get(s->manager->users, ULONG_TO_PTR((unsigned long) u));
+                user = hashmap_get(s->manager->users, UID_TO_PTR(u));
                 if (!user) {
                         log_error("User of session %s not known.", s->id);
                         return -ENOENT;
@@ -388,10 +406,10 @@ int session_load(Session *s) {
         if (!s->seat || !seat_has_vts(s->seat))
                 s->vtnr = 0;
 
-        if (pos && s->seat) {
+        if (position && s->seat) {
                 unsigned int npos;
 
-                safe_atou(pos, &npos);
+                safe_atou(position, &npos);
                 seat_claim_position(s->seat, s, npos);
         }
 
@@ -417,29 +435,27 @@ int session_load(Session *s) {
                         s->class = c;
         }
 
+        if (state && streq(state, "closing"))
+                s->stopping = true;
+
         if (s->fifo_path) {
                 int fd;
 
                 /* If we open an unopened pipe for reading we will not
                    get an EOF. to trigger an EOF we hence open it for
-                   reading, but close it right-away which then will
-                   trigger the EOF. */
+                   writing, but close it right away which then will
+                   trigger the EOF. This will happen immediately if no
+                   other process has the FIFO open for writing, i. e.
+                   when the session died before logind (re)started. */
 
                 fd = session_create_fifo(s);
                 safe_close(fd);
         }
 
-        if (realtime) {
-                unsigned long long l;
-                if (sscanf(realtime, "%llu", &l) > 0)
-                        s->timestamp.realtime = l;
-        }
-
-        if (monotonic) {
-                unsigned long long l;
-                if (sscanf(monotonic, "%llu", &l) > 0)
-                        s->timestamp.monotonic = l;
-        }
+        if (realtime)
+                timestamp_deserialize(realtime, &s->timestamp.realtime);
+        if (monotonic)
+                timestamp_deserialize(monotonic, &s->timestamp.monotonic);
 
         if (controller) {
                 if (bus_name_has_owner(s->manager->bus, controller, NULL) > 0)
@@ -458,7 +474,7 @@ int session_activate(Session *s) {
         assert(s->user);
 
         if (!s->seat)
-                return -ENOTSUP;
+                return -EOPNOTSUPP;
 
         if (s->seat->active == s)
                 return 0;
@@ -466,7 +482,7 @@ int session_activate(Session *s) {
         /* on seats with VTs, we let VTs manage session-switching */
         if (seat_has_vts(s->seat)) {
                 if (!s->vtnr)
-                        return -ENOTSUP;
+                        return -EOPNOTSUPP;
 
                 return chvt(s->vtnr);
         }
@@ -488,30 +504,37 @@ int session_activate(Session *s) {
         return 0;
 }
 
+#if 0 /// UNNEEDED by elogind
 static int session_start_scope(Session *s) {
         int r;
 
         assert(s);
         assert(s->user);
-        assert(s->user->slice);
 
         if (!s->scope) {
-                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
-                _cleanup_free_ char *description = NULL;
+                _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
                 char *scope, *job = NULL;
-
-                description = strjoin("Session ", s->id, " of user ", s->user->name, NULL);
-                if (!description)
-                        return log_oom();
+                const char *description;
 
                 scope = strjoin("session-", s->id, ".scope", NULL);
                 if (!scope)
                         return log_oom();
 
-                r = manager_start_scope(s->manager, scope, s->leader, s->user->slice, description, "systemd-logind.service", "systemd-user-sessions.service", &error, &job);
+                description = strjoina("Session ", s->id, " of user ", s->user->name, NULL);
+
+                r = manager_start_scope(
+                                s->manager,
+                                scope,
+                                s->leader,
+                                s->user->slice,
+                                description,
+                                "systemd-logind.service",
+                                "systemd-user-sessions.service",
+                                (uint64_t) -1, /* disable TasksMax= for the scope, rely on the slice setting for it */
+                                &error,
+                                &job);
                 if (r < 0) {
-                        log_error("Failed to start session scope %s: %s %s",
-                                  scope, bus_error_message(&error, r), error.name);
+                        log_error_errno(r, "Failed to start session scope %s: %s", scope, bus_error_message(&error, r));
                         free(scope);
                         return r;
                 } else {
@@ -523,11 +546,32 @@ static int session_start_scope(Session *s) {
         }
 
         if (s->scope)
-                hashmap_put(s->manager->session_units, s->scope, s);
+                (void) hashmap_put(s->manager->session_units, s->scope, s);
+
+        return 0;
+}
+#endif // 0
+
+static int session_start_cgroup(Session *s) {
+        int r;
+
+        assert(s);
+        assert(s->user);
+        assert(s->leader > 0);
+
+        /* First, create our own group */
+        r = cg_create(SYSTEMD_CGROUP_CONTROLLER, s->id);
+        if (r < 0)
+                return log_error_errno(r, "Failed to create cgroup %s: %m", s->id);
+
+        r = cg_attach(SYSTEMD_CGROUP_CONTROLLER, s->id, s->leader);
+        if (r < 0)
+                log_warning_errno(r, "Failed to attach PID %d to cgroup %s: %m", s->leader, s->id);
 
         return 0;
 }
 
+
 int session_start(Session *s) {
         int r;
 
@@ -544,7 +588,13 @@ int session_start(Session *s) {
                 return r;
 
         /* Create cgroup */
+/// elogind does its own session management without systemd units,
+/// slices and scopes
+#if 0
         r = session_start_scope(s);
+#else
+        r = session_start_cgroup(s);
+#endif // 0
         if (r < 0)
                 return r;
 
@@ -585,8 +635,9 @@ int session_start(Session *s) {
         return 0;
 }
 
+#if 0 /// UNNEEDED by elogind
 static int session_stop_scope(Session *s, bool force) {
-        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
         char *job = NULL;
         int r;
 
@@ -614,6 +665,22 @@ static int session_stop_scope(Session *s, bool force) {
 
         return 0;
 }
+#endif // 0
+
+static int session_stop_cgroup(Session *s, bool force) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        int r;
+
+        assert(s);
+
+        if (force || manager_shall_kill(s->manager, s->user->name)) {
+                r = session_kill(s, KILL_ALL, SIGTERM);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
 
 int session_stop(Session *s, bool force) {
         int r;
@@ -625,11 +692,18 @@ int session_stop(Session *s, bool force) {
 
         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 
+        if (s->seat)
+                seat_evict_position(s->seat, s);
+
         /* We are going down, don't care about FIFOs anymore */
         session_remove_fifo(s);
 
         /* Kill cgroup */
+#if 0 /// elogind does not start scopes, but sessions
         r = session_stop_scope(s, force);
+#else
+        r = session_stop_cgroup(s, force);
+#endif // 0
 
         s->stopping = true;
 
@@ -642,7 +716,6 @@ int session_stop(Session *s, bool force) {
 }
 
 int session_finalize(Session *s) {
-        int r = 0;
         SessionDevice *sd;
 
         assert(s);
@@ -661,11 +734,14 @@ int session_finalize(Session *s) {
 
         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 
+        if (s->seat)
+                seat_evict_position(s->seat, s);
+
         /* Kill session devices */
         while ((sd = hashmap_first(s->devices)))
                 session_device_free(sd);
 
-        unlink(s->state_file);
+        (void) unlink(s->state_file);
         session_add_to_gc_queue(s);
         user_add_to_gc_queue(s->user);
 
@@ -685,9 +761,10 @@ int session_finalize(Session *s) {
         user_save(s->user);
         user_send_changed(s->user, "Sessions", "Display", NULL);
 
-        return r;
+        return 0;
 }
 
+#if 0 /// UNNEEDED by elogind
 static int release_timeout_callback(sd_event_source *es, uint64_t usec, void *userdata) {
         Session *s = userdata;
 
@@ -697,19 +774,30 @@ static int release_timeout_callback(sd_event_source *es, uint64_t usec, void *us
         session_stop(s, false);
         return 0;
 }
+#endif // 0
 
-void session_release(Session *s) {
+int session_release(Session *s) {
         assert(s);
 
         if (!s->started || s->stopping)
-                return;
+                return 0;
+
+        if (s->timer_event_source)
+                return 0;
 
-        if (!s->timer_event_source)
-                sd_event_add_time(s->manager->event,
-                                  &s->timer_event_source,
-                                  CLOCK_MONOTONIC,
-                                  now(CLOCK_MONOTONIC) + RELEASE_USEC, 0,
-                                  release_timeout_callback, s);
+        /* In systemd, session release is triggered by user jobs
+           dying.  In elogind we don't have that so go ahead and stop
+           now.  */
+#if 0
+        return sd_event_add_time(s->manager->event,
+                                 &s->timer_event_source,
+                                 CLOCK_MONOTONIC,
+                                 now(CLOCK_MONOTONIC) + RELEASE_USEC, 0,
+                                 release_timeout_callback, s);
+
+#else
+        return session_stop(s, false);
+#endif // 0
 }
 
 bool session_is_active(Session *s) {
@@ -895,8 +983,7 @@ static void session_remove_fifo(Session *s) {
 
         if (s->fifo_path) {
                 unlink(s->fifo_path);
-                free(s->fifo_path);
-                s->fifo_path = NULL;
+                s->fifo_path = mfree(s->fifo_path);
         }
 }
 
@@ -914,11 +1001,17 @@ bool session_check_gc(Session *s, bool drop_not_started) {
                         return true;
         }
 
+#if 0 /// elogind supports neither scopes nor jobs
         if (s->scope_job && manager_job_is_active(s->manager, s->scope_job))
                 return true;
 
         if (s->scope && manager_unit_is_active(s->manager, s->scope))
                 return true;
+#endif // 0
+
+        if ( s->user->manager
+          && (cg_is_empty_recursive (SYSTEMD_CGROUP_CONTROLLER, s->user->manager->cgroup_root) > 0) )
+                return true;
 
         return false;
 }
@@ -940,7 +1033,11 @@ SessionState session_get_state(Session *s) {
         if (s->stopping || s->timer_event_source)
                 return SESSION_CLOSING;
 
+#if 0 /// elogind does not support systemd scope_jobs
         if (s->scope_job || s->fifo_fd < 0)
+#else
+        if (s->fifo_fd < 0)
+#endif // 0
                 return SESSION_OPENING;
 
         if (session_is_active(s))
@@ -952,10 +1049,30 @@ SessionState session_get_state(Session *s) {
 int session_kill(Session *s, KillWho who, int signo) {
         assert(s);
 
+#if 0 /// Without direct cgroup support, elogind can not kill sessions
         if (!s->scope)
                 return -ESRCH;
 
         return manager_kill_unit(s->manager, s->scope, who, signo, NULL);
+#else
+        if (who == KILL_LEADER) {
+                if (s->leader <= 0)
+                        return -ESRCH;
+
+                /* FIXME: verify that leader is in cgroup?  */
+
+                if (kill(s->leader, signo) < 0) {
+                        return log_error_errno(errno, "Failed to kill process leader %d for session %s: %m", s->leader, s->id);
+                }
+                return 0;
+        } else {
+                bool sigcont = false;
+                bool ignore_self = true;
+                bool rem = true;
+                return cg_kill_recursive (SYSTEMD_CGROUP_CONTROLLER, s->id, signo,
+                                          sigcont, ignore_self, rem, NULL);
+        }
+#endif // 0
 }
 
 static int session_open_vt(Session *s) {
@@ -968,11 +1085,9 @@ static int session_open_vt(Session *s) {
                 return s->vtfd;
 
         sprintf(path, "/dev/tty%u", s->vtnr);
-        s->vtfd = open(path, O_RDWR | O_CLOEXEC | O_NONBLOCK | O_NOCTTY);
-        if (s->vtfd < 0) {
-                log_error("cannot open VT %s of session %s: %m", path, s->id);
-                return -errno;
-        }
+        s->vtfd = open_terminal(path, O_RDWR | O_CLOEXEC | O_NONBLOCK | O_NOCTTY);
+        if (s->vtfd < 0)
+                return log_error_errno(s->vtfd, "cannot open VT %s of session %s: %m", path, s->id);
 
         return s->vtfd;
 }
@@ -990,22 +1105,25 @@ int session_prepare_vt(Session *s) {
 
         r = fchown(vt, s->user->uid, -1);
         if (r < 0) {
-                r = -errno;
-                log_error("Cannot change owner of /dev/tty%u: %m", s->vtnr);
+                r = log_error_errno(errno,
+                                    "Cannot change owner of /dev/tty%u: %m",
+                                    s->vtnr);
                 goto error;
         }
 
         r = ioctl(vt, KDSKBMODE, K_OFF);
         if (r < 0) {
-                r = -errno;
-                log_error("Cannot set K_OFF on /dev/tty%u: %m", s->vtnr);
+                r = log_error_errno(errno,
+                                    "Cannot set K_OFF on /dev/tty%u: %m",
+                                    s->vtnr);
                 goto error;
         }
 
         r = ioctl(vt, KDSETMODE, KD_GRAPHICS);
         if (r < 0) {
-                r = -errno;
-                log_error("Cannot set KD_GRAPHICS on /dev/tty%u: %m", s->vtnr);
+                r = log_error_errno(errno,
+                                    "Cannot set KD_GRAPHICS on /dev/tty%u: %m",
+                                    s->vtnr);
                 goto error;
         }
 
@@ -1017,8 +1135,9 @@ int session_prepare_vt(Session *s) {
         mode.acqsig = SIGRTMIN + 1;
         r = ioctl(vt, VT_SETMODE, &mode);
         if (r < 0) {
-                r = -errno;
-                log_error("Cannot set VT_PROCESS on /dev/tty%u: %m", s->vtnr);
+                r = log_error_errno(errno,
+                                    "Cannot set VT_PROCESS on /dev/tty%u: %m",
+                                    s->vtnr);
                 goto error;
         }
 
@@ -1030,25 +1149,40 @@ error:
 }
 
 void session_restore_vt(Session *s) {
+
+        static const struct vt_mode mode = {
+                .mode = VT_AUTO,
+        };
+
         _cleanup_free_ char *utf8 = NULL;
-        int vt, kb = K_XLATE;
-        struct vt_mode mode = { 0 };
+        int vt, kb, old_fd;
+
+        /* We need to get a fresh handle to the virtual terminal,
+         * since the old file-descriptor is potentially in a hung-up
+         * state after the controlling process exited; we do a
+         * little dance to avoid having the terminal be available
+         * for reuse before we've cleaned it up.
+         */
+        old_fd = s->vtfd;
+        s->vtfd = -1;
 
         vt = session_open_vt(s);
+        safe_close(old_fd);
+
         if (vt < 0)
                 return;
 
-        ioctl(vt, KDSETMODE, KD_TEXT);
+        (void) ioctl(vt, KDSETMODE, KD_TEXT);
 
         if (read_one_line_file("/sys/module/vt/parameters/default_utf8", &utf8) >= 0 && *utf8 == '1')
                 kb = K_UNICODE;
+        else
+                kb = K_XLATE;
 
-        ioctl(vt, KDSKBMODE, kb);
-
-        mode.mode = VT_AUTO;
-        ioctl(vt, VT_SETMODE, &mode);
+        (void) ioctl(vt, KDSKBMODE, kb);
 
-        fchown(vt, 0, -1);
+        (void) ioctl(vt, VT_SETMODE, &mode);
+        (void) fchown(vt, 0, (gid_t) -1);
 
         s->vtfd = safe_close(s->vtfd);
 }
@@ -1075,7 +1209,7 @@ void session_leave_vt(Session *s) {
         session_device_pause_all(s);
         r = ioctl(s->vtfd, VT_RELDISP, 1);
         if (r < 0)
-                log_debug("Cannot release VT of session %s: %m", s->id);
+                log_debug_errno(errno, "Cannot release VT of session %s: %m", s->id);
 }
 
 bool session_is_controller(Session *s, const char *sender) {
@@ -1103,7 +1237,18 @@ static void session_release_controller(Session *s, bool notify) {
                 session_device_free(sd);
 
         s->controller = NULL;
-        manager_drop_busname(s->manager, name);
+        s->track = sd_bus_track_unref(s->track);
+}
+
+static int on_bus_track(sd_bus_track *track, void *userdata) {
+        Session *s = userdata;
+
+        assert(track);
+        assert(s);
+
+        session_drop_controller(s);
+
+        return 0;
 }
 
 int session_set_controller(Session *s, const char *sender, bool force) {
@@ -1122,8 +1267,13 @@ int session_set_controller(Session *s, const char *sender, bool force) {
         if (!name)
                 return -ENOMEM;
 
-        r = manager_watch_busname(s->manager, name);
-        if (r)
+        s->track = sd_bus_track_unref(s->track);
+        r = sd_bus_track_new(s->manager->bus, &s->track, on_bus_track, s);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_track_add_name(s->track, name);
+        if (r < 0)
                 return r;
 
         /* When setting a session controller, we forcibly mute the VT and set
@@ -1136,7 +1286,7 @@ int session_set_controller(Session *s, const char *sender, bool force) {
          * or reset the VT in case it crashed/exited, too. */
         r = session_prepare_vt(s);
         if (r < 0) {
-                manager_drop_busname(s->manager, name);
+                s->track = sd_bus_track_unref(s->track);
                 return r;
         }
 
@@ -1154,6 +1304,7 @@ void session_drop_controller(Session *s) {
         if (!s->controller)
                 return;
 
+        s->track = sd_bus_track_unref(s->track);
         session_release_controller(s, false);
         session_save(s);
         session_restore_vt(s);