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/* SPDX-License-Identifier: LGPL-2.1+ */
#include <stdint.h>
#include <sys/mount.h>
#include "sd-bus.h"
#include "bus-error.h"
#include "dev-setup.h"
#include "fs-util.h"
#include "format-util.h"
#include "label.h"
#include "main-func.h"
#include "mkdir.h"
#include "mountpoint-util.h"
#include "path-util.h"
#include "rm-rf.h"
#include "selinux-util.h"
#include "smack-util.h"
#include "stdio-util.h"
#include "string-util.h"
#include "strv.h"
#include "user-util.h"
static int acquire_runtime_dir_size(uint64_t *ret) {
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
int r;
r = sd_bus_default_system(&bus);
if (r < 0)
return log_error_errno(r, "Failed to connect to system bus: %m");
r = sd_bus_get_property_trivial(bus, "org.freedesktop.login1", "/org/freedesktop/login1", "org.freedesktop.login1.Manager", "RuntimeDirectorySize", &error, 't', ret);
if (r < 0)
return log_error_errno(r, "Failed to acquire runtime directory size: %s", bus_error_message(&error, r));
return 0;
}
static int user_mkdir_runtime_path(
const char *runtime_path,
uid_t uid,
gid_t gid,
uint64_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(uint64_t)];
xsprintf(options,
"mode=0700,uid=" UID_FMT ",gid=" GID_FMT ",size=%" PRIu64 "%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);
}
/* Set up inaccessible nodes now so they're available if we decide to use them with user namespaces. */
(void) make_inaccessible_nodes(runtime_path, uid, gid);
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_debug_errno(r, "Failed to remove runtime directory %s (before unmounting), ignoring: %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_debug_errno(errno, "Failed to unmount user runtime directory %s, ignoring: %m", runtime_path);
r = rm_rf(runtime_path, REMOVE_ROOT);
if (r < 0 && r != -ENOENT)
return log_error_errno(r, "Failed to remove runtime directory %s (after unmounting): %m", runtime_path);
return 0;
}
static int do_mount(const char *user) {
char runtime_path[sizeof("/run/user") + DECIMAL_STR_MAX(uid_t)];
uint64_t runtime_dir_size;
uid_t uid;
gid_t gid;
int r;
r = get_user_creds(&user, &uid, &gid, NULL, NULL, 0);
if (r < 0)
return 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);
r = acquire_runtime_dir_size(&runtime_dir_size);
if (r < 0)
return r;
xsprintf(runtime_path, "/run/user/" UID_FMT, uid);
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 *user) {
char runtime_path[sizeof("/run/user") + DECIMAL_STR_MAX(uid_t)];
uid_t uid;
int r;
/* The user may be already removed. So, first try to parse the string by parse_uid(),
* and if it fails, fallback to get_user_creds().*/
if (parse_uid(user, &uid) < 0) {
r = get_user_creds(&user, &uid, NULL, NULL, NULL, 0);
if (r < 0)
return 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);
}
xsprintf(runtime_path, "/run/user/" UID_FMT, uid);
log_debug("Will remove %s", runtime_path);
return user_remove_runtime_path(runtime_path);
}
static int run(int argc, char *argv[]) {
int r;
log_parse_environment();
log_open();
if (argc != 3)
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"This program takes two arguments.");
if (!STR_IN_SET(argv[1], "start", "stop"))
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"First argument must be either \"start\" or \"stop\".");
r = mac_selinux_init();
if (r < 0)
return log_error_errno(r, "Could not initialize labelling: %m\n");
umask(0022);
if (streq(argv[1], "start"))
return do_mount(argv[2]);
if (streq(argv[1], "stop"))
return do_umount(argv[2]);
assert_not_reached("Unknown verb!");
}
DEFINE_MAIN_FUNCTION(run);
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