chiark / gitweb /
logind: split %t directory creation to a helper unit
authorZbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Sat, 9 Dec 2017 18:30:17 +0000 (19:30 +0100)
committerSven Eden <yamakuzure@gmx.net>
Fri, 24 Aug 2018 14:47:08 +0000 (16:47 +0200)
Unfortunately this needs a new binary to do the mount because there's just
too many special steps to outsource this to systemd-mount:
- EPERM needs to be treated specially
- UserRuntimeDir= setting must be obeyed
- SELinux label must be adjusted

This allows user@.service to be started independently of logind.
So 'systemctl start user@nnn' will start the user manager for user nnn.
Logind will start it too when the user logs in, and will stop it (unless
lingering is enabled) when the user logs out.

Fixes #7339.

meson.build
src/login/logind-user.c
src/login/meson.build
src/login/user-runtime-dir.c [new file with mode: 0644]

index 44076e185745ad421fb69030964fc3faa664da5c..242ff92fa50332a50edc0aa16b8432ca37156b60 100644 (file)
@@ -444,7 +444,8 @@ if cc.get_id() == 'clang'
         foreach arg : ['-Wno-typedef-redefinition',
                        '-Wno-gnu-variable-sized-type-not-at-end',
                       ]
-                if cc.has_argument(arg)
+                if cc.has_argument(arg,
+                                   name : '@0@ is supported'.format(arg))
                         add_project_arguments(arg, language : 'c')
                 endif
         endforeach
@@ -1916,6 +1917,13 @@ exe = executable('elogind-inhibit',
                         install : true,
                         install_dir : rootbindir)
 public_programs += [exe]
+executable('elogind-user-runtime-dir',
+           user_runtime_dir_sources,
+           include_directories : includes,
+           link_with : [libshared, liblogind_core],
+           install_rpath : rootlibexecdir,
+           install : true,
+           install_dir : rootlibexecdir)
 
 if conf.get('HAVE_PAM') == 1
         version_script_arg = join_paths(meson.current_source_dir(), pam_elogind_sym)
index 69ff15f390134df4d93a1c81319fed768677b85e..2b9dce162cd4625140a62f34301d1bb6770d6bb5 100644 (file)
@@ -325,54 +325,6 @@ int user_load(User *u) {
         return r;
 }
 
-static int user_mkdir_runtime_path(User *u) {
-        int r;
-
-        assert(u);
-
-        r = mkdir_safe_label("/run/user", 0755, 0, 0, MKDIR_WARN_MODE);
-        if (r < 0)
-                return log_error_errno(r, "Failed to create /run/user: %m");
-
-        if (path_is_mount_point(u->runtime_path, NULL, 0) <= 0) {
-                _cleanup_free_ char *t = NULL;
-
-                r = asprintf(&t, "mode=0700,uid=" UID_FMT ",gid=" GID_FMT ",size=%zu%s",
-                             u->uid, u->gid, u->manager->runtime_dir_size,
-                             mac_smack_use() ? ",smackfsroot=*" : "");
-                if (r < 0)
-                        return log_oom();
-
-                (void) mkdir_label(u->runtime_path, 0700);
-
-                r = mount("tmpfs", u->runtime_path, "tmpfs", MS_NODEV|MS_NOSUID, t);
-                if (r < 0) {
-                        if (!IN_SET(errno, EPERM, EACCES)) {
-                                r = log_error_errno(errno, "Failed to mount per-user tmpfs directory %s: %m", u->runtime_path);
-                                goto fail;
-                        }
-
-                        log_debug_errno(errno, "Failed to mount per-user tmpfs directory %s, assuming containerized execution, ignoring: %m", u->runtime_path);
-
-                        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(u->runtime_path, 0);
-                if (r < 0)
-                        log_warning_errno(r, "Failed to fix label of '%s', ignoring: %m", u->runtime_path);
-        }
-
-        return 0;
-
-fail:
-        /* Try to clean up, but ignore errors */
-        (void) rmdir(u->runtime_path);
-        return r;
-}
 
 #if 0 /// elogind can not ask systemd via dbus to start user services
 #else
@@ -432,15 +384,9 @@ int user_start(User *u) {
          */
         u->stopping = false;
 
-        if (!u->started) {
+        if (!u->started)
                 log_debug("Starting services for new user %s.", u->name);
 
-                /* Make XDG_RUNTIME_DIR */
-                r = user_mkdir_runtime_path(u);
-                if (r < 0)
-                        return r;
-        }
-
         /* Save the user data so far, because pam_systemd will read the
          * XDG_RUNTIME_DIR out of it while starting up systemd --user.
          * We need to do user_save_internal() because we have not
@@ -503,29 +449,6 @@ static int user_stop_service(User *u) {
 }
 #endif // 0
 
-static int user_remove_runtime_path(User *u) {
-        int r;
-
-        assert(u);
-
-        r = rm_rf(u->runtime_path, 0);
-        if (r < 0)
-                log_error_errno(r, "Failed to remove runtime directory %s (before unmounting): %m", u->runtime_path);
-
-        /* Ignore cases where the directory isn't mounted, as that's
-         * quite possible, if we lacked the permissions to mount
-         * something */
-        r = umount2(u->runtime_path, MNT_DETACH);
-        if (r < 0 && !IN_SET(errno, EINVAL, ENOENT))
-                log_error_errno(errno, "Failed to unmount user runtime directory %s: %m", u->runtime_path);
-
-        r = rm_rf(u->runtime_path, REMOVE_ROOT);
-        if (r < 0)
-                log_error_errno(r, "Failed to remove runtime directory %s (after unmounting): %m", u->runtime_path);
-
-        return r;
-}
-
 int user_stop(User *u, bool force) {
         Session *s;
         int r = 0, k;
@@ -580,11 +503,6 @@ int user_finalize(User *u) {
                         r = k;
         }
 
-        /* Kill XDG_RUNTIME_DIR */
-        k = user_remove_runtime_path(u);
-        if (k < 0)
-                r = k;
-
         /* Clean SysV + POSIX IPC objects, but only if this is not a system user. Background: in many setups cronjobs
          * are run in full PAM and thus logind sessions, even if the code run doesn't belong to actual users but to
          * system components. Since enable RemoveIPC= globally for all users, we need to be a bit careful with such
index 2bd5016cf97fab9fe31ddd9439c609e3bd34f2f2..af58bb11a565ad3cbbc19ac43a6d73897d6cd412 100644 (file)
@@ -89,8 +89,12 @@ loginctl_sources = files('''
 loginctl_sources += files('''
         eloginctl.c
         eloginctl.h
+user_runtime_dir_sources = files('''
+        user-runtime-dir.c
+        logind.h
 '''.split())
 #endif // 1
+
 #if 0 /// elogind builds itself unconditionally and with some adaptations
 # if conf.get('ENABLE_LOGIND') == 1
 #         logind_conf = configure_file(
diff --git a/src/login/user-runtime-dir.c b/src/login/user-runtime-dir.c
new file mode 100644 (file)
index 0000000..8f38e58
--- /dev/null
@@ -0,0 +1,170 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+//#include <stdint.h>
+//#include <sys/mount.h>
+
+//#include "fs-util.h"
+//#include "label.h"
+//#include "logind.h"
+//#include "mkdir.h"
+//#include "mount-util.h"
+//#include "path-util.h"
+//#include "rm-rf.h"
+//#include "smack-util.h"
+//#include "stdio-util.h"
+//#include "string-util.h"
+//#include "strv.h"
+//#include "user-util.h"
+
+static int gather_configuration(size_t *runtime_dir_size) {
+        Manager m = {};
+        int r;
+
+        manager_reset_config(&m);
+
+        r = manager_parse_config_file(&m);
+        if (r < 0)
+                log_warning_errno(r, "Failed to parse logind.conf: %m");
+
+        *runtime_dir_size = m.runtime_dir_size;
+        return 0;
+}
+
+static int user_mkdir_runtime_path(const char *runtime_path, uid_t uid, gid_t gid, size_t runtime_dir_size) {
+        int r;
+
+        assert(runtime_path);
+        assert(path_is_absolute(runtime_path));
+        assert(uid_is_valid(uid));
+        assert(gid_is_valid(gid));
+
+        r = mkdir_safe_label("/run/user", 0755, 0, 0, MKDIR_WARN_MODE);
+        if (r < 0)
+                return log_error_errno(r, "Failed to create /run/user: %m");
+
+        if (path_is_mount_point(runtime_path, NULL, 0) >= 0)
+                log_debug("%s is already a mount point", runtime_path);
+        else {
+                char options[sizeof("mode=0700,uid=,gid=,size=,smackfsroot=*")
+                             + DECIMAL_STR_MAX(uid_t)
+                             + DECIMAL_STR_MAX(gid_t)
+                             + DECIMAL_STR_MAX(size_t)];
+
+                xsprintf(options,
+                         "mode=0700,uid=" UID_FMT ",gid=" GID_FMT ",size=%zu%s",
+                         uid, gid, runtime_dir_size,
+                         mac_smack_use() ? ",smackfsroot=*" : "");
+
+                (void) mkdir_label(runtime_path, 0700);
+
+                r = mount("tmpfs", runtime_path, "tmpfs", MS_NODEV|MS_NOSUID, options);
+                if (r < 0) {
+                        if (!IN_SET(errno, EPERM, EACCES)) {
+                                r = log_error_errno(errno, "Failed to mount per-user tmpfs directory %s: %m", runtime_path);
+                                goto fail;
+                        }
+
+                        log_debug_errno(errno, "Failed to mount per-user tmpfs directory %s.\n"
+                                        "Assuming containerized execution, ignoring: %m", runtime_path);
+
+                        r = chmod_and_chown(runtime_path, 0700, uid, gid);
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to change ownership and mode of \"%s\": %m", runtime_path);
+                                goto fail;
+                        }
+                }
+
+                r = label_fix(runtime_path, 0);
+                if (r < 0)
+                        log_warning_errno(r, "Failed to fix label of \"%s\", ignoring: %m", runtime_path);
+        }
+
+        return 0;
+
+fail:
+        /* Try to clean up, but ignore errors */
+        (void) rmdir(runtime_path);
+        return r;
+}
+
+static int user_remove_runtime_path(const char *runtime_path) {
+        int r;
+
+        assert(runtime_path);
+        assert(path_is_absolute(runtime_path));
+
+        r = rm_rf(runtime_path, 0);
+        if (r < 0)
+                log_error_errno(r, "Failed to remove runtime directory %s (before unmounting): %m", runtime_path);
+
+        /* Ignore cases where the directory isn't mounted, as that's
+         * quite possible, if we lacked the permissions to mount
+         * something */
+        r = umount2(runtime_path, MNT_DETACH);
+        if (r < 0 && !IN_SET(errno, EINVAL, ENOENT))
+                log_error_errno(errno, "Failed to unmount user runtime directory %s: %m", runtime_path);
+
+        r = rm_rf(runtime_path, REMOVE_ROOT);
+        if (r < 0)
+                log_error_errno(r, "Failed to remove runtime directory %s (after unmounting): %m", runtime_path);
+
+        return r;
+}
+
+static int do_mount(const char *runtime_path, uid_t uid, gid_t gid) {
+        size_t runtime_dir_size;
+
+        assert_se(gather_configuration(&runtime_dir_size) == 0);
+
+        log_debug("Will mount %s owned by "UID_FMT":"GID_FMT, runtime_path, uid, gid);
+        return user_mkdir_runtime_path(runtime_path, uid, gid, runtime_dir_size);
+}
+
+static int do_umount(const char *runtime_path) {
+        log_debug("Will remove %s", runtime_path);
+        return user_remove_runtime_path(runtime_path);
+}
+
+int main(int argc, char *argv[]) {
+        const char *user;
+        uid_t uid;
+        gid_t gid;
+        char runtime_path[sizeof("/run/user") + DECIMAL_STR_MAX(uid_t)];
+        int r;
+
+        log_parse_environment();
+        log_open();
+
+        if (argc != 3) {
+                log_error("This program takes two arguments.");
+                return EXIT_FAILURE;
+        }
+        if (!STR_IN_SET(argv[1], "start", "stop")) {
+                log_error("First argument must be either \"start\" or \"stop\".");
+                return EXIT_FAILURE;
+        }
+
+        umask(0022);
+
+        user = argv[2];
+        r = get_user_creds(&user, &uid, &gid, NULL, NULL);
+        if (r < 0) {
+                log_error_errno(r,
+                                r == -ESRCH ? "No such user \"%s\"" :
+                                r == -ENOMSG ? "UID \"%s\" is invalid or has an invalid main group"
+                                             : "Failed to look up user \"%s\": %m",
+                                user);
+                return EXIT_FAILURE;
+        }
+
+        xsprintf(runtime_path, "/run/user/" UID_FMT, uid);
+
+        if (streq(argv[1], "start"))
+                r = do_mount(runtime_path, uid, gid);
+        else if (streq(argv[1], "stop"))
+                r = do_umount(runtime_path);
+        else
+                assert_not_reached("Unknown verb!");
+
+        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
+}