Merge pull request #1918 from dvdhrm/user3

login: allow re-using users (v3)

5 files changed, 149 insertions, 188 deletions

diff --git a/src/login/logind-core.c b/src/login/logind-core.c
index b3f30c8dc9..38c426c1aa 100644
--- a/src/login/logind-core.c
+++ b/src/login/logind-core.c
@@ -98,15 +98,16 @@ int manager_add_session(Manager *m, const char *id, Session **_session) {
 
 int manager_add_user(Manager *m, uid_t uid, gid_t gid, const char *name, User **_user) {
         User *u;
+        int r;
 
         assert(m);
         assert(name);
 
         u = hashmap_get(m->users, UID_TO_PTR(uid));
         if (!u) {
-                u = user_new(m, uid, gid, name);
-                if (!u)
-                        return -ENOMEM;
+                r = user_new(&u, m, uid, gid, name);
+                if (r < 0)
+                        return r;
         }
 
         if (_user)
diff --git a/src/login/logind-dbus.c b/src/login/logind-dbus.c
index 7cc0044bab..e507a19aef 100644
--- a/src/login/logind-dbus.c
+++ b/src/login/logind-dbus.c
@@ -2620,11 +2620,8 @@ int match_job_removed(sd_bus_message *message, void *userdata, sd_bus_error *err
         }
 
         session = hashmap_get(m->session_units, unit);
-        if (session) {
-
-                if (streq_ptr(path, session->scope_job))
-                        session->scope_job = mfree(session->scope_job);
-
+        if (session && streq_ptr(path, session->scope_job)) {
+                session->scope_job = mfree(session->scope_job);
                 session_jobs_reply(session, unit, result);
 
                 session_save(session);
@@ -2633,7 +2630,9 @@ int match_job_removed(sd_bus_message *message, void *userdata, sd_bus_error *err
         }
 
         user = hashmap_get(m->user_units, unit);
-        if (user) {
+        if (user &&
+            (streq_ptr(path, user->service_job) ||
+             streq_ptr(path, user->slice_job))) {
 
                 if (streq_ptr(path, user->service_job))
                         user->service_job = mfree(user->service_job);
@@ -2964,7 +2963,7 @@ int manager_start_unit(Manager *manager, const char *unit, sd_bus_error *error,
                         "StartUnit",
                         error,
                         &reply,
-                        "ss", unit, "fail");
+                        "ss", unit, "replace");
         if (r < 0)
                 return r;
 
diff --git a/src/login/logind-user.c b/src/login/logind-user.c
index 7bdbe6583c..778f19b50d 100644
--- a/src/login/logind-user.c
+++ b/src/login/logind-user.c
@@ -51,42 +51,62 @@
 #include "user-util.h"
 #include "util.h"
 
-User* user_new(Manager *m, uid_t uid, gid_t gid, const char *name) {
-        User *u;
+int user_new(User **out, Manager *m, uid_t uid, gid_t gid, const char *name) {
+        _cleanup_(user_freep) User *u = NULL;
+        char lu[DECIMAL_STR_MAX(uid_t) + 1];
+        int r;
 
+        assert(out);
         assert(m);
         assert(name);
 
         u = new0(User, 1);
         if (!u)
-                return NULL;
+                return -ENOMEM;
+
+        u->manager = m;
+        u->uid = uid;
+        u->gid = gid;
+        xsprintf(lu, UID_FMT, uid);
 
         u->name = strdup(name);
         if (!u->name)
-                goto fail;
+                return -ENOMEM;
 
         if (asprintf(&u->state_file, "/run/systemd/users/"UID_FMT, uid) < 0)
-                goto fail;
+                return -ENOMEM;
 
-        if (hashmap_put(m->users, UID_TO_PTR(uid), u) < 0)
-                goto fail;
+        if (asprintf(&u->runtime_path, "/run/user/"UID_FMT, uid) < 0)
+                return -ENOMEM;
 
-        u->manager = m;
-        u->uid = uid;
-        u->gid = gid;
+        r = slice_build_subslice(SPECIAL_USER_SLICE, lu, &u->slice);
+        if (r < 0)
+                return r;
 
-        return u;
+        r = unit_name_build("user", lu, ".service", &u->service);
+        if (r < 0)
+                return r;
 
-fail:
-        free(u->state_file);
-        free(u->name);
-        free(u);
+        r = hashmap_put(m->users, UID_TO_PTR(uid), u);
+        if (r < 0)
+                return r;
+
+        r = hashmap_put(m->user_units, u->slice, u);
+        if (r < 0)
+                return r;
 
-        return NULL;
+        r = hashmap_put(m->user_units, u->service, u);
+        if (r < 0)
+                return r;
+
+        *out = u;
+        u = NULL;
+        return 0;
 }
 
-void user_free(User *u) {
-        assert(u);
+User *user_free(User *u) {
+        if (!u)
+                return NULL;
 
         if (u->in_gc_queue)
                 LIST_REMOVE(gc_queue, u->manager->user_gc_queue, u);
@@ -94,26 +114,24 @@ void user_free(User *u) {
         while (u->sessions)
                 session_free(u->sessions);
 
-        if (u->slice) {
-                hashmap_remove(u->manager->user_units, u->slice);
-                free(u->slice);
-        }
+        if (u->service)
+                hashmap_remove_value(u->manager->user_units, u->service, u);
 
-        if (u->service) {
-                hashmap_remove(u->manager->user_units, u->service);
-                free(u->service);
-        }
+        if (u->slice)
+                hashmap_remove_value(u->manager->user_units, u->slice, u);
 
-        free(u->slice_job);
-        free(u->service_job);
+        hashmap_remove_value(u->manager->users, UID_TO_PTR(u->uid), u);
 
-        free(u->runtime_path);
+        u->slice_job = mfree(u->slice_job);
+        u->service_job = mfree(u->service_job);
 
-        hashmap_remove(u->manager->users, UID_TO_PTR(u->uid));
+        u->service = mfree(u->service);
+        u->slice = mfree(u->slice);
+        u->runtime_path = mfree(u->runtime_path);
+        u->state_file = mfree(u->state_file);
+        u->name = mfree(u->name);
 
-        free(u->name);
-        free(u->state_file);
-        free(u);
+        return mfree(u);
 }
 
 static int user_save_internal(User *u) {
@@ -141,16 +159,13 @@ static int user_save_internal(User *u) {
                 u->name,
                 user_state_to_string(user_get_state(u)));
 
+        /* LEGACY: no-one reads RUNTIME= anymore, drop it at some point */
         if (u->runtime_path)
                 fprintf(f, "RUNTIME=%s\n", u->runtime_path);
 
-        if (u->service)
-                fprintf(f, "SERVICE=%s\n", u->service);
         if (u->service_job)
                 fprintf(f, "SERVICE_JOB=%s\n", u->service_job);
 
-        if (u->slice)
-                fprintf(f, "SLICE=%s\n", u->slice);
         if (u->slice_job)
                 fprintf(f, "SLICE_JOB=%s\n", u->slice_job);
 
@@ -288,10 +303,7 @@ int user_load(User *u) {
         assert(u);
 
         r = parse_env_file(u->state_file, NEWLINE,
-                           "RUNTIME",     &u->runtime_path,
-                           "SERVICE",     &u->service,
                            "SERVICE_JOB", &u->service_job,
-                           "SLICE",       &u->slice,
                            "SLICE_JOB",   &u->slice_job,
                            "DISPLAY",     &display,
                            "REALTIME",    &realtime,
@@ -327,7 +339,6 @@ int user_load(User *u) {
 }
 
 static int user_mkdir_runtime_path(User *u) {
-        char *p;
         int r;
 
         assert(u);
@@ -336,16 +347,10 @@ static int user_mkdir_runtime_path(User *u) {
         if (r < 0)
                 return log_error_errno(r, "Failed to create /run/user: %m");
 
-        if (!u->runtime_path) {
-                if (asprintf(&p, "/run/user/" UID_FMT, u->uid) < 0)
-                        return log_oom();
-        } else
-                p = u->runtime_path;
-
-        if (path_is_mount_point(p, 0) <= 0) {
+        if (path_is_mount_point(u->runtime_path, 0) <= 0) {
                 _cleanup_free_ char *t = NULL;
 
-                (void) mkdir_label(p, 0700);
+                (void) mkdir_label(u->runtime_path, 0700);
 
                 if (mac_smack_use())
                         r = asprintf(&t, "mode=0700,smackfsroot=*,uid=" UID_FMT ",gid=" GID_FMT ",size=%zu", u->uid, u->gid, u->manager->runtime_dir_size);
@@ -356,10 +361,10 @@ static int user_mkdir_runtime_path(User *u) {
                         goto fail;
                 }
 
-                r = mount("tmpfs", p, "tmpfs", MS_NODEV|MS_NOSUID, t);
+                r = mount("tmpfs", u->runtime_path, "tmpfs", MS_NODEV|MS_NOSUID, t);
                 if (r < 0) {
                         if (errno != EPERM) {
-                                r = log_error_errno(errno, "Failed to mount per-user tmpfs directory %s: %m", p);
+                                r = log_error_errno(errno, "Failed to mount per-user tmpfs directory %s: %m", u->runtime_path);
                                 goto fail;
                         }
 
@@ -367,79 +372,54 @@ static int user_mkdir_runtime_path(User *u) {
                          * CAP_SYS_ADMIN-less container? In this case,
                          * just use a normal directory. */
 
-                        r = chmod_and_chown(p, 0700, u->uid, u->gid);
+                        r = chmod_and_chown(u->runtime_path, 0700, u->uid, u->gid);
                         if (r < 0) {
                                 log_error_errno(r, "Failed to change runtime directory ownership and mode: %m");
                                 goto fail;
                         }
                 }
 
-                r = label_fix(p, false, false);
+                r = label_fix(u->runtime_path, false, false);
                 if (r < 0)
-                        log_warning_errno(r, "Failed to fix label of '%s', ignoring: %m", p);
+                        log_warning_errno(r, "Failed to fix label of '%s', ignoring: %m", u->runtime_path);
         }
 
-        u->runtime_path = p;
         return 0;
 
 fail:
-        if (p) {
-                /* Try to clean up, but ignore errors */
-                (void) rmdir(p);
-                free(p);
-        }
-
-        u->runtime_path = NULL;
+        /* Try to clean up, but ignore errors */
+        (void) rmdir(u->runtime_path);
         return r;
 }
 
 static int user_start_slice(User *u) {
+        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+        const char *description;
+        char *job;
         int r;
 
         assert(u);
 
-        if (!u->slice) {
-                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
-                char lu[DECIMAL_STR_MAX(uid_t) + 1], *slice, *job;
-                const char *description;
-
-                u->slice_job  = mfree(u->slice_job);
-
-                xsprintf(lu, UID_FMT, u->uid);
-                r = slice_build_subslice(SPECIAL_USER_SLICE, lu, &slice);
-                if (r < 0)
-                        return log_error_errno(r, "Failed to build slice name: %m");
-
-                description = strjoina("User Slice of ", u->name);
-
-                r = manager_start_slice(
-                                u->manager,
-                                slice,
-                                description,
-                                "systemd-logind.service",
-                                "systemd-user-sessions.service",
-                                u->manager->user_tasks_max,
-                                &error,
-                                &job);
-                if (r < 0) {
-
-                        if (sd_bus_error_has_name(&error, BUS_ERROR_UNIT_EXISTS))
-                                /* The slice already exists? If so, that's fine, let's just reuse it */
-                                u->slice = slice;
-                        else {
-                                log_error_errno(r, "Failed to start user slice %s, ignoring: %s (%s)", slice, bus_error_message(&error, r), error.name);
-                                free(slice);
-                                /* we don't fail due to this, let's try to continue */
-                        }
-                } else {
-                        u->slice = slice;
-                        u->slice_job = job;
-                }
+        u->slice_job = mfree(u->slice_job);
+        description = strjoina("User Slice of ", u->name);
+
+        r = manager_start_slice(
+                        u->manager,
+                        u->slice,
+                        description,
+                        "systemd-logind.service",
+                        "systemd-user-sessions.service",
+                        u->manager->user_tasks_max,
+                        &error,
+                        &job);
+        if (r < 0) {
+                /* we don't fail due to this, let's try to continue */
+                if (!sd_bus_error_has_name(&error, BUS_ERROR_UNIT_EXISTS))
+                        log_error_errno(r, "Failed to start user slice %s, ignoring: %s (%s)", u->slice, bus_error_message(&error, r), error.name);
+        } else {
+                u->slice_job = job;
         }
 
-        if (u->slice)
-                (void) hashmap_put(u->manager->user_units, u->slice, u);
-
         return 0;
 }
 
@@ -450,34 +430,20 @@ static int user_start_service(User *u) {
 
         assert(u);
 
-        if (!u->service) {
-                char lu[DECIMAL_STR_MAX(uid_t) + 1], *service;
+        u->service_job = mfree(u->service_job);
 
-                xsprintf(lu, UID_FMT, u->uid);
-                r = unit_name_build("user", lu, ".service", &service);
-                if (r < 0)
-                        return log_error_errno(r, "Failed to build service name: %m");
-
-                r = manager_start_unit(
-                                u->manager,
-                                service,
-                                &error,
-                                &job);
-                if (r < 0) {
-                        log_error_errno(r, "Failed to start user service, ignoring: %s", bus_error_message(&error, r));
-                        free(service);
-                        /* we don't fail due to this, let's try to continue */
-                } else {
-                        u->service = service;
-
-                        free(u->service_job);
-                        u->service_job = job;
-                }
+        r = manager_start_unit(
+                        u->manager,
+                        u->service,
+                        &error,
+                        &job);
+        if (r < 0) {
+                /* we don't fail due to this, let's try to continue */
+                log_error_errno(r, "Failed to start user service, ignoring: %s", bus_error_message(&error, r));
+        } else {
+                u->service_job = job;
         }
 
-        if (u->service)
-                (void) hashmap_put(u->manager->user_units, u->service, u);
-
         return 0;
 }
 
@@ -486,15 +452,32 @@ int user_start(User *u) {
 
         assert(u);
 
-        if (u->started)
+        if (u->started && !u->stopping)
                 return 0;
 
-        log_debug("New user %s logged in.", u->name);
-
-        /* Make XDG_RUNTIME_DIR */
-        r = user_mkdir_runtime_path(u);
-        if (r < 0)
-                return r;
+        /*
+         * If u->stopping is set, the user is marked for removal and the slice
+         * and service stop-jobs are queued. We have to clear that flag before
+         * queing the start-jobs again. If they succeed, the user object can be
+         * re-used just fine (pid1 takes care of job-ordering and proper
+         * restart), but if they fail, we want to force another user_stop() so
+         * possibly pending units are stopped.
+         * Note that we don't clear u->started, as we have no clue what state
+         * the user is in on failure here. Hence, we pretend the user is
+         * running so it will be properly taken down by GC. However, we clearly
+         * return an error from user_start() in that case, so no further
+         * reference to the user is taken.
+         */
+        u->stopping = false;
+
+        if (!u->started) {
+                log_debug("New user %s logged in.", u->name);
+
+                /* Make XDG_RUNTIME_DIR */
+                r = user_mkdir_runtime_path(u);
+                if (r < 0)
+                        return r;
+        }
 
         /* Create cgroup */
         r = user_start_slice(u);
@@ -512,16 +495,16 @@ int user_start(User *u) {
         if (r < 0)
                 return r;
 
-        if (!dual_timestamp_is_set(&u->timestamp))
-                dual_timestamp_get(&u->timestamp);
-
-        u->started = true;
+        if (!u->started) {
+                if (!dual_timestamp_is_set(&u->timestamp))
+                        dual_timestamp_get(&u->timestamp);
+                user_send_signal(u, true);
+                u->started = true;
+        }
 
         /* Save new user data */
         user_save(u);
 
-        user_send_signal(u, true);
-
         return 0;
 }
 
@@ -532,9 +515,6 @@ static int user_stop_slice(User *u) {
 
         assert(u);
 
-        if (!u->slice)
-                return 0;
-
         r = manager_stop_unit(u->manager, u->slice, &error, &job);
         if (r < 0) {
                 log_error("Failed to stop user slice: %s", bus_error_message(&error, r));
@@ -554,9 +534,6 @@ static int user_stop_service(User *u) {
 
         assert(u);
 
-        if (!u->service)
-                return 0;
-
         r = manager_stop_unit(u->manager, u->service, &error, &job);
         if (r < 0) {
                 log_error("Failed to stop user service: %s", bus_error_message(&error, r));
@@ -574,9 +551,6 @@ static int user_remove_runtime_path(User *u) {
 
         assert(u);
 
-        if (!u->runtime_path)
-                return 0;
-
         r = rm_rf(u->runtime_path, 0);
         if (r < 0)
                 log_error_errno(r, "Failed to remove runtime directory %s: %m", u->runtime_path);
@@ -592,8 +566,6 @@ static int user_remove_runtime_path(User *u) {
         if (r < 0)
                 log_error_errno(r, "Failed to remove runtime directory %s: %m", u->runtime_path);
 
-        u->runtime_path = mfree(u->runtime_path);
-
         return r;
 }
 
@@ -785,9 +757,6 @@ UserState user_get_state(User *u) {
 int user_kill(User *u, int signo) {
         assert(u);
 
-        if (!u->slice)
-                return -ESRCH;
-
         return manager_kill_unit(u->manager, u->slice, KILL_ALL, signo, NULL);
 }
 
diff --git a/src/login/logind-user.h b/src/login/logind-user.h
index 722247806b..de99cf47b4 100644
--- a/src/login/logind-user.h
+++ b/src/login/logind-user.h
@@ -39,16 +39,13 @@ typedef enum UserState {
 
 struct User {
         Manager *manager;
-
         uid_t uid;
         gid_t gid;
         char *name;
-
         char *state_file;
         char *runtime_path;
-
-        char *service;
         char *slice;
+        char *service;
 
         char *service_job;
         char *slice_job;
@@ -65,8 +62,11 @@ struct User {
         LIST_FIELDS(User, gc_queue);
 };
 
-User* user_new(Manager *m, uid_t uid, gid_t gid, const char *name);
-void user_free(User *u);
+int user_new(User **out, Manager *m, uid_t uid, gid_t gid, const char *name);
+User *user_free(User *u);
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(User *, user_free);
+
 bool user_check_gc(User *u, bool drop_not_started);
 void user_add_to_gc_queue(User *u);
 int user_start(User *u);
diff --git a/src/login/pam_systemd.c b/src/login/pam_systemd.c
index 0d61f528db..3f7cbb78df 100644
--- a/src/login/pam_systemd.c
+++ b/src/login/pam_systemd.c
@@ -267,29 +267,21 @@ _public_ PAM_EXTERN int pam_sm_open_session(
 
         pam_get_item(handle, PAM_SERVICE, (const void**) &service);
         if (streq_ptr(service, "systemd-user")) {
-                _cleanup_free_ char *p = NULL, *rt = NULL;
+                _cleanup_free_ char *rt = NULL;
 
-                if (asprintf(&p, "/run/systemd/users/"UID_FMT, pw->pw_uid) < 0)
+                if (asprintf(&rt, "/run/user/"UID_FMT, pw->pw_uid) < 0)
                         return PAM_BUF_ERR;
 
-                r = parse_env_file(p, NEWLINE,
-                                   "RUNTIME", &rt,
-                                   NULL);
-                if (r < 0 && r != -ENOENT)
-                        return PAM_SESSION_ERR;
-
-                if (rt)  {
-                        r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", rt, 0);
-                        if (r != PAM_SUCCESS) {
-                                pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
-                                return r;
-                        }
-
-                        r = export_legacy_dbus_address(handle, pw->pw_uid, rt);
-                        if (r != PAM_SUCCESS)
-                                return r;
+                r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", rt, 0);
+                if (r != PAM_SUCCESS) {
+                        pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
+                        return r;
                 }
 
+                r = export_legacy_dbus_address(handle, pw->pw_uid, rt);
+                if (r != PAM_SUCCESS)
+                        return r;
+
                 return PAM_SUCCESS;
         }