1461 lines
50 KiB
C
1461 lines
50 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
|
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/***
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||
This file is part of systemd.
|
||
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Copyright 2015 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
|
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under the terms of the GNU Lesser General Public License as published by
|
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the Free Software Foundation; either version 2.1 of the License, or
|
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(at your option) any later version.
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||
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systemd is distributed in the hope that it will be useful, but
|
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WITHOUT ANY WARRANTY; without even the implied warranty of
|
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <sys/mount.h>
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#include <linux/magic.h>
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||
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#include "alloc-util.h"
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#include "escape.h"
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||
#include "fd-util.h"
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#include "fileio.h"
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#include "fs-util.h"
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#include "label.h"
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#include "mkdir.h"
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#include "mount-util.h"
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#include "nspawn-mount.h"
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#include "parse-util.h"
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#include "path-util.h"
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#include "rm-rf.h"
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#include "set.h"
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#include "stat-util.h"
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#include "string-util.h"
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#include "strv.h"
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#include "user-util.h"
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#include "util.h"
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CustomMount* custom_mount_add(CustomMount **l, unsigned *n, CustomMountType t) {
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CustomMount *c, *ret;
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assert(l);
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assert(n);
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assert(t >= 0);
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assert(t < _CUSTOM_MOUNT_TYPE_MAX);
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c = reallocarray(*l, *n + 1, sizeof(CustomMount));
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if (!c)
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return NULL;
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*l = c;
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ret = *l + *n;
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(*n)++;
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*ret = (CustomMount) { .type = t };
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return ret;
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}
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void custom_mount_free_all(CustomMount *l, unsigned n) {
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unsigned i;
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for (i = 0; i < n; i++) {
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CustomMount *m = l + i;
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free(m->source);
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free(m->destination);
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free(m->options);
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if (m->work_dir) {
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(void) rm_rf(m->work_dir, REMOVE_ROOT|REMOVE_PHYSICAL);
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free(m->work_dir);
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}
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if (m->rm_rf_tmpdir) {
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(void) rm_rf(m->rm_rf_tmpdir, REMOVE_ROOT|REMOVE_PHYSICAL);
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free(m->rm_rf_tmpdir);
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}
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strv_free(m->lower);
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}
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free(l);
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}
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static int custom_mount_compare(const void *a, const void *b) {
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const CustomMount *x = a, *y = b;
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int r;
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r = path_compare(x->destination, y->destination);
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if (r != 0)
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return r;
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if (x->type < y->type)
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return -1;
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if (x->type > y->type)
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return 1;
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return 0;
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}
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static bool source_path_is_valid(const char *p) {
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assert(p);
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if (*p == '+')
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p++;
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return path_is_absolute(p);
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}
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static char *resolve_source_path(const char *dest, const char *source) {
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if (!source)
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return NULL;
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if (source[0] == '+')
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return prefix_root(dest, source + 1);
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return strdup(source);
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}
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int custom_mount_prepare_all(const char *dest, CustomMount *l, unsigned n) {
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unsigned i;
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int r;
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/* Prepare all custom mounts. This will make source we know all temporary directories. This is called in the
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* parent process, so that we know the temporary directories to remove on exit before we fork off the
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* children. */
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assert(l || n == 0);
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/* Order the custom mounts, and make sure we have a working directory */
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qsort_safe(l, n, sizeof(CustomMount), custom_mount_compare);
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for (i = 0; i < n; i++) {
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CustomMount *m = l + i;
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if (m->source) {
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char *s;
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s = resolve_source_path(dest, m->source);
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if (!s)
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return log_oom();
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free(m->source);
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m->source = s;
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} else {
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/* No source specified? In that case, use a throw-away temporary directory in /var/tmp */
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m->rm_rf_tmpdir = strdup("/var/tmp/nspawn-temp-XXXXXX");
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if (!m->rm_rf_tmpdir)
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return log_oom();
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if (!mkdtemp(m->rm_rf_tmpdir)) {
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m->rm_rf_tmpdir = mfree(m->rm_rf_tmpdir);
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return log_error_errno(errno, "Failed to acquire temporary directory: %m");
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}
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m->source = strjoin(m->rm_rf_tmpdir, "/src");
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if (!m->source)
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return log_oom();
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if (mkdir(m->source, 0755) < 0)
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return log_error_errno(errno, "Failed to create %s: %m", m->source);
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}
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if (m->type == CUSTOM_MOUNT_OVERLAY) {
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char **j;
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||
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STRV_FOREACH(j, m->lower) {
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char *s;
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||
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s = resolve_source_path(dest, *j);
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if (!s)
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return log_oom();
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free(*j);
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*j = s;
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}
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if (m->work_dir) {
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char *s;
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s = resolve_source_path(dest, m->work_dir);
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if (!s)
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return log_oom();
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free(m->work_dir);
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m->work_dir = s;
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} else {
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assert(m->source);
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r = tempfn_random(m->source, NULL, &m->work_dir);
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if (r < 0)
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return log_error_errno(r, "Failed to acquire working directory: %m");
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}
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(void) mkdir_label(m->work_dir, 0700);
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}
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}
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return 0;
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}
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int bind_mount_parse(CustomMount **l, unsigned *n, const char *s, bool read_only) {
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_cleanup_free_ char *source = NULL, *destination = NULL, *opts = NULL;
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const char *p = s;
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CustomMount *m;
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int r;
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assert(l);
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assert(n);
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r = extract_many_words(&p, ":", EXTRACT_DONT_COALESCE_SEPARATORS, &source, &destination, NULL);
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if (r < 0)
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return r;
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if (r == 0)
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return -EINVAL;
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if (r == 1) {
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destination = strdup(source[0] == '+' ? source+1 : source);
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if (!destination)
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return -ENOMEM;
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||
}
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||
if (r == 2 && !isempty(p)) {
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||
opts = strdup(p);
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if (!opts)
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return -ENOMEM;
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||
}
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||
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if (isempty(source))
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source = NULL;
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else if (!source_path_is_valid(source))
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return -EINVAL;
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||
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if (!path_is_absolute(destination))
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return -EINVAL;
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||
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m = custom_mount_add(l, n, CUSTOM_MOUNT_BIND);
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if (!m)
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return -ENOMEM;
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m->source = source;
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m->destination = destination;
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m->read_only = read_only;
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m->options = opts;
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source = destination = opts = NULL;
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return 0;
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}
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int tmpfs_mount_parse(CustomMount **l, unsigned *n, const char *s) {
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_cleanup_free_ char *path = NULL, *opts = NULL;
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const char *p = s;
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CustomMount *m;
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int r;
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assert(l);
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assert(n);
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assert(s);
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r = extract_first_word(&p, &path, ":", EXTRACT_DONT_COALESCE_SEPARATORS);
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if (r < 0)
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return r;
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if (r == 0)
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return -EINVAL;
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if (isempty(p))
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opts = strdup("mode=0755");
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else
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opts = strdup(p);
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if (!opts)
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return -ENOMEM;
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if (!path_is_absolute(path))
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return -EINVAL;
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m = custom_mount_add(l, n, CUSTOM_MOUNT_TMPFS);
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if (!m)
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return -ENOMEM;
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m->destination = path;
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m->options = opts;
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path = opts = NULL;
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return 0;
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}
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int overlay_mount_parse(CustomMount **l, unsigned *n, const char *s, bool read_only) {
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_cleanup_free_ char *upper = NULL, *destination = NULL;
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_cleanup_strv_free_ char **lower = NULL;
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CustomMount *m;
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int k;
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k = strv_split_extract(&lower, s, ":", EXTRACT_DONT_COALESCE_SEPARATORS);
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if (k < 0)
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return k;
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if (k < 2)
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return -EADDRNOTAVAIL;
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if (k == 2) {
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/* If two parameters are specified, the first one is the lower, the second one the upper directory. And
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* we'll also define the destination mount point the same as the upper. */
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if (!source_path_is_valid(lower[0]) ||
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!source_path_is_valid(lower[1]))
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return -EINVAL;
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upper = TAKE_PTR(lower[1]);
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destination = strdup(upper[0] == '+' ? upper+1 : upper); /* take the destination without "+" prefix */
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if (!destination)
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return -ENOMEM;
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} else {
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char **i;
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/* If more than two parameters are specified, the last one is the destination, the second to last one
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* the "upper", and all before that the "lower" directories. */
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destination = lower[k - 1];
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upper = TAKE_PTR(lower[k - 2]);
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STRV_FOREACH(i, lower)
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if (!source_path_is_valid(*i))
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return -EINVAL;
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/* If the upper directory is unspecified, then let's create it automatically as a throw-away directory
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* in /var/tmp */
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if (isempty(upper))
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upper = NULL;
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else if (!source_path_is_valid(upper))
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return -EINVAL;
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if (!path_is_absolute(destination))
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return -EINVAL;
|
||
}
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||
|
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m = custom_mount_add(l, n, CUSTOM_MOUNT_OVERLAY);
|
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if (!m)
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return -ENOMEM;
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||
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m->destination = destination;
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m->source = upper;
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m->lower = lower;
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m->read_only = read_only;
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upper = destination = NULL;
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lower = NULL;
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||
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return 0;
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||
}
|
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static int tmpfs_patch_options(
|
||
const char *options,
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bool userns,
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uid_t uid_shift, uid_t uid_range,
|
||
bool patch_ids,
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const char *selinux_apifs_context,
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char **ret) {
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||
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char *buf = NULL;
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||
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if ((userns && uid_shift != 0) || patch_ids) {
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assert(uid_shift != UID_INVALID);
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|
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if (asprintf(&buf, "%s%suid=" UID_FMT ",gid=" UID_FMT,
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strempty(options), options ? "," : "",
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uid_shift, uid_shift) < 0)
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return -ENOMEM;
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||
|
||
options = buf;
|
||
}
|
||
|
||
#if HAVE_SELINUX
|
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if (selinux_apifs_context) {
|
||
char *t;
|
||
|
||
t = strjoin(strempty(options), options ? "," : "",
|
||
"context=\"", selinux_apifs_context, "\"");
|
||
free(buf);
|
||
if (!t)
|
||
return -ENOMEM;
|
||
|
||
buf = t;
|
||
}
|
||
#endif
|
||
|
||
if (!buf && options) {
|
||
buf = strdup(options);
|
||
if (!buf)
|
||
return -ENOMEM;
|
||
}
|
||
*ret = buf;
|
||
|
||
return !!buf;
|
||
}
|
||
|
||
int mount_sysfs(const char *dest, MountSettingsMask mount_settings) {
|
||
const char *full, *top, *x;
|
||
int r;
|
||
unsigned long extra_flags = 0;
|
||
|
||
top = prefix_roota(dest, "/sys");
|
||
r = path_is_fs_type(top, SYSFS_MAGIC);
|
||
if (r < 0)
|
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return log_error_errno(r, "Failed to determine filesystem type of %s: %m", top);
|
||
/* /sys might already be mounted as sysfs by the outer child in the
|
||
* !netns case. In this case, it's all good. Don't touch it because we
|
||
* don't have the right to do so, see https://github.com/systemd/systemd/issues/1555.
|
||
*/
|
||
if (r > 0)
|
||
return 0;
|
||
|
||
full = prefix_roota(top, "/full");
|
||
|
||
(void) mkdir(full, 0755);
|
||
|
||
if (mount_settings & MOUNT_APPLY_APIVFS_RO)
|
||
extra_flags |= MS_RDONLY;
|
||
|
||
r = mount_verbose(LOG_ERR, "sysfs", full, "sysfs",
|
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MS_NOSUID|MS_NOEXEC|MS_NODEV|extra_flags, NULL);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
FOREACH_STRING(x, "block", "bus", "class", "dev", "devices", "kernel") {
|
||
_cleanup_free_ char *from = NULL, *to = NULL;
|
||
|
||
from = prefix_root(full, x);
|
||
if (!from)
|
||
return log_oom();
|
||
|
||
to = prefix_root(top, x);
|
||
if (!to)
|
||
return log_oom();
|
||
|
||
(void) mkdir(to, 0755);
|
||
|
||
r = mount_verbose(LOG_ERR, from, to, NULL, MS_BIND, NULL);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
r = mount_verbose(LOG_ERR, NULL, to, NULL,
|
||
MS_BIND|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT|extra_flags, NULL);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
r = umount_verbose(full);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
if (rmdir(full) < 0)
|
||
return log_error_errno(errno, "Failed to remove %s: %m", full);
|
||
|
||
/* Create mountpoint for cgroups. Otherwise we are not allowed since we
|
||
* remount /sys read-only.
|
||
*/
|
||
if (cg_ns_supported()) {
|
||
x = prefix_roota(top, "/fs/cgroup");
|
||
(void) mkdir_p(x, 0755);
|
||
}
|
||
|
||
return mount_verbose(LOG_ERR, NULL, top, NULL,
|
||
MS_BIND|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT|extra_flags, NULL);
|
||
}
|
||
|
||
static int mkdir_userns(const char *path, mode_t mode, MountSettingsMask mask, uid_t uid_shift) {
|
||
int r;
|
||
|
||
assert(path);
|
||
|
||
r = mkdir_errno_wrapper(path, mode);
|
||
if (r < 0 && r != -EEXIST)
|
||
return r;
|
||
|
||
if ((mask & MOUNT_USE_USERNS) == 0)
|
||
return 0;
|
||
|
||
if (mask & MOUNT_IN_USERNS)
|
||
return 0;
|
||
|
||
if (lchown(path, uid_shift, uid_shift) < 0)
|
||
return -errno;
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int mkdir_userns_p(const char *prefix, const char *path, mode_t mode, MountSettingsMask mask, uid_t uid_shift) {
|
||
const char *p, *e;
|
||
int r;
|
||
|
||
assert(path);
|
||
|
||
if (prefix && !path_startswith(path, prefix))
|
||
return -ENOTDIR;
|
||
|
||
/* create every parent directory in the path, except the last component */
|
||
p = path + strspn(path, "/");
|
||
for (;;) {
|
||
char t[strlen(path) + 1];
|
||
|
||
e = p + strcspn(p, "/");
|
||
p = e + strspn(e, "/");
|
||
|
||
/* Is this the last component? If so, then we're done */
|
||
if (*p == 0)
|
||
break;
|
||
|
||
memcpy(t, path, e - path);
|
||
t[e-path] = 0;
|
||
|
||
if (prefix && path_startswith(prefix, t))
|
||
continue;
|
||
|
||
r = mkdir_userns(t, mode, mask, uid_shift);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
return mkdir_userns(path, mode, mask, uid_shift);
|
||
}
|
||
|
||
int mount_all(const char *dest,
|
||
MountSettingsMask mount_settings,
|
||
uid_t uid_shift, uid_t uid_range,
|
||
const char *selinux_apifs_context) {
|
||
|
||
typedef struct MountPoint {
|
||
const char *what;
|
||
const char *where;
|
||
const char *type;
|
||
const char *options;
|
||
unsigned long flags;
|
||
MountSettingsMask mount_settings;
|
||
} MountPoint;
|
||
|
||
static const MountPoint mount_table[] = {
|
||
/* inner child mounts */
|
||
{ "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, MOUNT_FATAL|MOUNT_IN_USERNS },
|
||
{ "/proc/sys", "/proc/sys", NULL, NULL, MS_BIND, MOUNT_FATAL|MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* Bind mount first ... */
|
||
{ "/proc/sys/net", "/proc/sys/net", NULL, NULL, MS_BIND, MOUNT_FATAL|MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO|MOUNT_APPLY_APIVFS_NETNS }, /* (except for this) */
|
||
{ NULL, "/proc/sys", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, MOUNT_FATAL|MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* ... then, make it r/o */
|
||
{ "/proc/sysrq-trigger", "/proc/sysrq-trigger", NULL, NULL, MS_BIND, MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* Bind mount first ... */
|
||
{ NULL, "/proc/sysrq-trigger", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* ... then, make it r/o */
|
||
|
||
/* outer child mounts */
|
||
{ "tmpfs", "/tmp", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV|MS_STRICTATIME, MOUNT_FATAL },
|
||
{ "tmpfs", "/sys", "tmpfs", "mode=755", MS_NOSUID|MS_NOEXEC|MS_NODEV, MOUNT_FATAL|MOUNT_APPLY_APIVFS_NETNS },
|
||
{ "sysfs", "/sys", "sysfs", NULL, MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV, MOUNT_FATAL|MOUNT_APPLY_APIVFS_RO }, /* skipped if above was mounted */
|
||
{ "sysfs", "/sys", "sysfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, MOUNT_FATAL }, /* skipped if above was mounted */
|
||
|
||
{ "tmpfs", "/dev", "tmpfs", "mode=755", MS_NOSUID|MS_STRICTATIME, MOUNT_FATAL },
|
||
{ "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV|MS_STRICTATIME, MOUNT_FATAL },
|
||
{ "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID|MS_NODEV|MS_STRICTATIME, MOUNT_FATAL },
|
||
#if HAVE_SELINUX
|
||
{ "/sys/fs/selinux", "/sys/fs/selinux", NULL, NULL, MS_BIND, 0 }, /* Bind mount first */
|
||
{ NULL, "/sys/fs/selinux", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, 0 }, /* Then, make it r/o */
|
||
#endif
|
||
};
|
||
|
||
unsigned k;
|
||
int r;
|
||
bool use_userns = (mount_settings & MOUNT_USE_USERNS);
|
||
bool netns = (mount_settings & MOUNT_APPLY_APIVFS_NETNS);
|
||
bool ro = (mount_settings & MOUNT_APPLY_APIVFS_RO);
|
||
bool in_userns = (mount_settings & MOUNT_IN_USERNS);
|
||
|
||
for (k = 0; k < ELEMENTSOF(mount_table); k++) {
|
||
_cleanup_free_ char *where = NULL, *options = NULL;
|
||
const char *o;
|
||
bool fatal = (mount_table[k].mount_settings & MOUNT_FATAL);
|
||
|
||
if (in_userns != (bool)(mount_table[k].mount_settings & MOUNT_IN_USERNS))
|
||
continue;
|
||
|
||
if (!netns && (bool)(mount_table[k].mount_settings & MOUNT_APPLY_APIVFS_NETNS))
|
||
continue;
|
||
|
||
if (!ro && (bool)(mount_table[k].mount_settings & MOUNT_APPLY_APIVFS_RO))
|
||
continue;
|
||
|
||
r = chase_symlinks(mount_table[k].where, dest, CHASE_NONEXISTENT|CHASE_PREFIX_ROOT, &where);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, mount_table[k].where);
|
||
|
||
r = path_is_mount_point(where, NULL, 0);
|
||
if (r < 0 && r != -ENOENT)
|
||
return log_error_errno(r, "Failed to detect whether %s is a mount point: %m", where);
|
||
|
||
/* Skip this entry if it is not a remount. */
|
||
if (mount_table[k].what && r > 0)
|
||
continue;
|
||
|
||
r = mkdir_userns_p(dest, where, 0755, mount_settings, uid_shift);
|
||
if (r < 0 && r != -EEXIST) {
|
||
if (fatal && r != -EROFS)
|
||
return log_error_errno(r, "Failed to create directory %s: %m", where);
|
||
|
||
log_debug_errno(r, "Failed to create directory %s: %m", where);
|
||
/* If we failed mkdir() or chown() due to the root
|
||
* directory being read only, attempt to mount this fs
|
||
* anyway and let mount_verbose log any errors */
|
||
if (r != -EROFS)
|
||
continue;
|
||
}
|
||
|
||
o = mount_table[k].options;
|
||
if (streq_ptr(mount_table[k].type, "tmpfs")) {
|
||
if (in_userns)
|
||
r = tmpfs_patch_options(o, use_userns, 0, uid_range, true, selinux_apifs_context, &options);
|
||
else
|
||
r = tmpfs_patch_options(o, use_userns, uid_shift, uid_range, false, selinux_apifs_context, &options);
|
||
if (r < 0)
|
||
return log_oom();
|
||
if (r > 0)
|
||
o = options;
|
||
}
|
||
|
||
r = mount_verbose(fatal ? LOG_ERR : LOG_DEBUG,
|
||
mount_table[k].what,
|
||
where,
|
||
mount_table[k].type,
|
||
mount_table[k].flags,
|
||
o);
|
||
if (r < 0 && fatal)
|
||
return r;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int mount_bind(const char *dest, CustomMount *m) {
|
||
|
||
_cleanup_free_ char *where = NULL;
|
||
struct stat source_st, dest_st;
|
||
int r;
|
||
|
||
assert(dest);
|
||
assert(m);
|
||
|
||
if (stat(m->source, &source_st) < 0)
|
||
return log_error_errno(errno, "Failed to stat %s: %m", m->source);
|
||
|
||
r = chase_symlinks(m->destination, dest, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &where);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, m->destination);
|
||
if (r > 0) { /* Path exists already? */
|
||
|
||
if (stat(where, &dest_st) < 0)
|
||
return log_error_errno(errno, "Failed to stat %s: %m", where);
|
||
|
||
if (S_ISDIR(source_st.st_mode) && !S_ISDIR(dest_st.st_mode)) {
|
||
log_error("Cannot bind mount directory %s on file %s.", m->source, where);
|
||
return -EINVAL;
|
||
}
|
||
|
||
if (!S_ISDIR(source_st.st_mode) && S_ISDIR(dest_st.st_mode)) {
|
||
log_error("Cannot bind mount file %s on directory %s.", m->source, where);
|
||
return -EINVAL;
|
||
}
|
||
|
||
} else { /* Path doesn't exist yet? */
|
||
r = mkdir_parents_label(where, 0755);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to make parents of %s: %m", where);
|
||
|
||
/* Create the mount point. Any non-directory file can be
|
||
* mounted on any non-directory file (regular, fifo, socket,
|
||
* char, block).
|
||
*/
|
||
if (S_ISDIR(source_st.st_mode))
|
||
r = mkdir_label(where, 0755);
|
||
else
|
||
r = touch(where);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to create mount point %s: %m", where);
|
||
|
||
}
|
||
|
||
r = mount_verbose(LOG_ERR, m->source, where, NULL, MS_BIND | MS_REC, m->options);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
if (m->read_only) {
|
||
r = bind_remount_recursive(where, true, NULL);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Read-only bind mount failed: %m");
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int mount_tmpfs(
|
||
const char *dest,
|
||
CustomMount *m,
|
||
bool userns, uid_t uid_shift, uid_t uid_range,
|
||
const char *selinux_apifs_context) {
|
||
|
||
const char *options;
|
||
_cleanup_free_ char *buf = NULL, *where = NULL;
|
||
int r;
|
||
|
||
assert(dest);
|
||
assert(m);
|
||
|
||
r = chase_symlinks(m->destination, dest, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &where);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, m->destination);
|
||
if (r == 0) { /* Doesn't exist yet? */
|
||
r = mkdir_p_label(where, 0755);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Creating mount point for tmpfs %s failed: %m", where);
|
||
}
|
||
|
||
r = tmpfs_patch_options(m->options, userns, uid_shift, uid_range, false, selinux_apifs_context, &buf);
|
||
if (r < 0)
|
||
return log_oom();
|
||
options = r > 0 ? buf : m->options;
|
||
|
||
return mount_verbose(LOG_ERR, "tmpfs", where, "tmpfs", MS_NODEV|MS_STRICTATIME, options);
|
||
}
|
||
|
||
static char *joined_and_escaped_lower_dirs(char **lower) {
|
||
_cleanup_strv_free_ char **sv = NULL;
|
||
|
||
sv = strv_copy(lower);
|
||
if (!sv)
|
||
return NULL;
|
||
|
||
strv_reverse(sv);
|
||
|
||
if (!strv_shell_escape(sv, ",:"))
|
||
return NULL;
|
||
|
||
return strv_join(sv, ":");
|
||
}
|
||
|
||
static int mount_overlay(const char *dest, CustomMount *m) {
|
||
|
||
_cleanup_free_ char *lower = NULL, *where = NULL, *escaped_source = NULL;
|
||
const char *options;
|
||
int r;
|
||
|
||
assert(dest);
|
||
assert(m);
|
||
|
||
r = chase_symlinks(m->destination, dest, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &where);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, m->destination);
|
||
if (r == 0) { /* Doesn't exist yet? */
|
||
r = mkdir_label(where, 0755);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Creating mount point for overlay %s failed: %m", where);
|
||
}
|
||
|
||
(void) mkdir_p_label(m->source, 0755);
|
||
|
||
lower = joined_and_escaped_lower_dirs(m->lower);
|
||
if (!lower)
|
||
return log_oom();
|
||
|
||
escaped_source = shell_escape(m->source, ",:");
|
||
if (!escaped_source)
|
||
return log_oom();
|
||
|
||
if (m->read_only)
|
||
options = strjoina("lowerdir=", escaped_source, ":", lower);
|
||
else {
|
||
_cleanup_free_ char *escaped_work_dir = NULL;
|
||
|
||
escaped_work_dir = shell_escape(m->work_dir, ",:");
|
||
if (!escaped_work_dir)
|
||
return log_oom();
|
||
|
||
options = strjoina("lowerdir=", lower, ",upperdir=", escaped_source, ",workdir=", escaped_work_dir);
|
||
}
|
||
|
||
return mount_verbose(LOG_ERR, "overlay", where, "overlay", m->read_only ? MS_RDONLY : 0, options);
|
||
}
|
||
|
||
int mount_custom(
|
||
const char *dest,
|
||
CustomMount *mounts, unsigned n,
|
||
bool userns, uid_t uid_shift, uid_t uid_range,
|
||
const char *selinux_apifs_context) {
|
||
|
||
unsigned i;
|
||
int r;
|
||
|
||
assert(dest);
|
||
|
||
for (i = 0; i < n; i++) {
|
||
CustomMount *m = mounts + i;
|
||
|
||
switch (m->type) {
|
||
|
||
case CUSTOM_MOUNT_BIND:
|
||
r = mount_bind(dest, m);
|
||
break;
|
||
|
||
case CUSTOM_MOUNT_TMPFS:
|
||
r = mount_tmpfs(dest, m, userns, uid_shift, uid_range, selinux_apifs_context);
|
||
break;
|
||
|
||
case CUSTOM_MOUNT_OVERLAY:
|
||
r = mount_overlay(dest, m);
|
||
break;
|
||
|
||
default:
|
||
assert_not_reached("Unknown custom mount type");
|
||
}
|
||
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Retrieve existing subsystems. This function is called in a new cgroup
|
||
* namespace.
|
||
*/
|
||
static int get_process_controllers(Set **ret) {
|
||
_cleanup_set_free_free_ Set *controllers = NULL;
|
||
_cleanup_fclose_ FILE *f = NULL;
|
||
int r;
|
||
|
||
assert(ret);
|
||
|
||
controllers = set_new(&string_hash_ops);
|
||
if (!controllers)
|
||
return -ENOMEM;
|
||
|
||
f = fopen("/proc/self/cgroup", "re");
|
||
if (!f)
|
||
return errno == ENOENT ? -ESRCH : -errno;
|
||
|
||
for (;;) {
|
||
_cleanup_free_ char *line = NULL;
|
||
char *e, *l;
|
||
|
||
r = read_line(f, LONG_LINE_MAX, &line);
|
||
if (r < 0)
|
||
return r;
|
||
if (r == 0)
|
||
break;
|
||
|
||
l = strchr(line, ':');
|
||
if (!l)
|
||
continue;
|
||
|
||
l++;
|
||
e = strchr(l, ':');
|
||
if (!e)
|
||
continue;
|
||
|
||
*e = 0;
|
||
|
||
if (STR_IN_SET(l, "", "name=systemd", "name=unified"))
|
||
continue;
|
||
|
||
r = set_put_strdup(controllers, l);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
*ret = controllers;
|
||
controllers = NULL;
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int mount_legacy_cgroup_hierarchy(
|
||
const char *dest,
|
||
const char *controller,
|
||
const char *hierarchy,
|
||
bool read_only) {
|
||
|
||
const char *to, *fstype, *opts;
|
||
int r;
|
||
|
||
to = strjoina(strempty(dest), "/sys/fs/cgroup/", hierarchy);
|
||
|
||
r = path_is_mount_point(to, dest, 0);
|
||
if (r < 0 && r != -ENOENT)
|
||
return log_error_errno(r, "Failed to determine if %s is mounted already: %m", to);
|
||
if (r > 0)
|
||
return 0;
|
||
|
||
mkdir_p(to, 0755);
|
||
|
||
/* The superblock mount options of the mount point need to be
|
||
* identical to the hosts', and hence writable... */
|
||
if (streq(controller, SYSTEMD_CGROUP_CONTROLLER_HYBRID)) {
|
||
fstype = "cgroup2";
|
||
opts = NULL;
|
||
} else if (streq(controller, SYSTEMD_CGROUP_CONTROLLER_LEGACY)) {
|
||
fstype = "cgroup";
|
||
opts = "none,name=systemd,xattr";
|
||
} else {
|
||
fstype = "cgroup";
|
||
opts = controller;
|
||
}
|
||
|
||
r = mount_verbose(LOG_ERR, "cgroup", to, fstype, MS_NOSUID|MS_NOEXEC|MS_NODEV, opts);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
/* ... hence let's only make the bind mount read-only, not the superblock. */
|
||
if (read_only) {
|
||
r = mount_verbose(LOG_ERR, NULL, to, NULL,
|
||
MS_BIND|MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, NULL);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Mount a legacy cgroup hierarchy when cgroup namespaces are supported. */
|
||
static int mount_legacy_cgns_supported(
|
||
const char *dest,
|
||
CGroupUnified unified_requested,
|
||
bool userns,
|
||
uid_t uid_shift,
|
||
uid_t uid_range,
|
||
const char *selinux_apifs_context) {
|
||
|
||
_cleanup_set_free_free_ Set *controllers = NULL;
|
||
const char *cgroup_root = "/sys/fs/cgroup", *c;
|
||
int r;
|
||
|
||
(void) mkdir_p(cgroup_root, 0755);
|
||
|
||
/* Mount a tmpfs to /sys/fs/cgroup if it's not mounted there yet. */
|
||
r = path_is_mount_point(cgroup_root, dest, AT_SYMLINK_FOLLOW);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to determine if /sys/fs/cgroup is already mounted: %m");
|
||
if (r == 0) {
|
||
_cleanup_free_ char *options = NULL;
|
||
|
||
/* When cgroup namespaces are enabled and user namespaces are
|
||
* used then the mount of the cgroupfs is done *inside* the new
|
||
* user namespace. We're root in the new user namespace and the
|
||
* kernel will happily translate our uid/gid to the correct
|
||
* uid/gid as seen from e.g. /proc/1/mountinfo. So we simply
|
||
* pass uid 0 and not uid_shift to tmpfs_patch_options().
|
||
*/
|
||
r = tmpfs_patch_options("mode=755", userns, 0, uid_range, true, selinux_apifs_context, &options);
|
||
if (r < 0)
|
||
return log_oom();
|
||
|
||
r = mount_verbose(LOG_ERR, "tmpfs", cgroup_root, "tmpfs",
|
||
MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME, options);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
r = cg_all_unified();
|
||
if (r < 0)
|
||
return r;
|
||
if (r > 0)
|
||
goto skip_controllers;
|
||
|
||
r = get_process_controllers(&controllers);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to determine cgroup controllers: %m");
|
||
|
||
for (;;) {
|
||
_cleanup_free_ const char *controller = NULL;
|
||
|
||
controller = set_steal_first(controllers);
|
||
if (!controller)
|
||
break;
|
||
|
||
r = mount_legacy_cgroup_hierarchy("", controller, controller, !userns);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
/* When multiple hierarchies are co-mounted, make their
|
||
* constituting individual hierarchies a symlink to the
|
||
* co-mount.
|
||
*/
|
||
c = controller;
|
||
for (;;) {
|
||
_cleanup_free_ char *target = NULL, *tok = NULL;
|
||
|
||
r = extract_first_word(&c, &tok, ",", 0);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to extract co-mounted cgroup controller: %m");
|
||
if (r == 0)
|
||
break;
|
||
|
||
if (streq(controller, tok))
|
||
break;
|
||
|
||
target = prefix_root("/sys/fs/cgroup/", tok);
|
||
if (!target)
|
||
return log_oom();
|
||
|
||
r = symlink_idempotent(controller, target);
|
||
if (r == -EINVAL)
|
||
return log_error_errno(r, "Invalid existing symlink for combined hierarchy: %m");
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to create symlink for combined hierarchy: %m");
|
||
}
|
||
}
|
||
|
||
skip_controllers:
|
||
if (unified_requested >= CGROUP_UNIFIED_SYSTEMD) {
|
||
r = mount_legacy_cgroup_hierarchy("", SYSTEMD_CGROUP_CONTROLLER_HYBRID, "unified", false);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
r = mount_legacy_cgroup_hierarchy("", SYSTEMD_CGROUP_CONTROLLER_LEGACY, "systemd", false);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
if (!userns)
|
||
return mount_verbose(LOG_ERR, NULL, cgroup_root, NULL,
|
||
MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME|MS_RDONLY, "mode=755");
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Mount legacy cgroup hierarchy when cgroup namespaces are unsupported. */
|
||
static int mount_legacy_cgns_unsupported(
|
||
const char *dest,
|
||
CGroupUnified unified_requested,
|
||
bool userns,
|
||
uid_t uid_shift,
|
||
uid_t uid_range,
|
||
const char *selinux_apifs_context) {
|
||
|
||
_cleanup_set_free_free_ Set *controllers = NULL;
|
||
const char *cgroup_root;
|
||
int r;
|
||
|
||
cgroup_root = prefix_roota(dest, "/sys/fs/cgroup");
|
||
|
||
(void) mkdir_p(cgroup_root, 0755);
|
||
|
||
/* Mount a tmpfs to /sys/fs/cgroup if it's not mounted there yet. */
|
||
r = path_is_mount_point(cgroup_root, dest, AT_SYMLINK_FOLLOW);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to determine if /sys/fs/cgroup is already mounted: %m");
|
||
if (r == 0) {
|
||
_cleanup_free_ char *options = NULL;
|
||
|
||
r = tmpfs_patch_options("mode=755", userns, uid_shift, uid_range, false, selinux_apifs_context, &options);
|
||
if (r < 0)
|
||
return log_oom();
|
||
|
||
r = mount_verbose(LOG_ERR, "tmpfs", cgroup_root, "tmpfs",
|
||
MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME, options);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
r = cg_all_unified();
|
||
if (r < 0)
|
||
return r;
|
||
if (r > 0)
|
||
goto skip_controllers;
|
||
|
||
r = cg_kernel_controllers(&controllers);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to determine cgroup controllers: %m");
|
||
|
||
for (;;) {
|
||
_cleanup_free_ char *controller = NULL, *origin = NULL, *combined = NULL;
|
||
|
||
controller = set_steal_first(controllers);
|
||
if (!controller)
|
||
break;
|
||
|
||
origin = prefix_root("/sys/fs/cgroup/", controller);
|
||
if (!origin)
|
||
return log_oom();
|
||
|
||
r = readlink_malloc(origin, &combined);
|
||
if (r == -EINVAL) {
|
||
/* Not a symbolic link, but directly a single cgroup hierarchy */
|
||
|
||
r = mount_legacy_cgroup_hierarchy(dest, controller, controller, true);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
} else if (r < 0)
|
||
return log_error_errno(r, "Failed to read link %s: %m", origin);
|
||
else {
|
||
_cleanup_free_ char *target = NULL;
|
||
|
||
target = prefix_root(dest, origin);
|
||
if (!target)
|
||
return log_oom();
|
||
|
||
/* A symbolic link, a combination of controllers in one hierarchy */
|
||
|
||
if (!filename_is_valid(combined)) {
|
||
log_warning("Ignoring invalid combined hierarchy %s.", combined);
|
||
continue;
|
||
}
|
||
|
||
r = mount_legacy_cgroup_hierarchy(dest, combined, combined, true);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
r = symlink_idempotent(combined, target);
|
||
if (r == -EINVAL)
|
||
return log_error_errno(r, "Invalid existing symlink for combined hierarchy: %m");
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to create symlink for combined hierarchy: %m");
|
||
}
|
||
}
|
||
|
||
skip_controllers:
|
||
if (unified_requested >= CGROUP_UNIFIED_SYSTEMD) {
|
||
r = mount_legacy_cgroup_hierarchy(dest, SYSTEMD_CGROUP_CONTROLLER_HYBRID, "unified", false);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
r = mount_legacy_cgroup_hierarchy(dest, SYSTEMD_CGROUP_CONTROLLER_LEGACY, "systemd", false);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
return mount_verbose(LOG_ERR, NULL, cgroup_root, NULL,
|
||
MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME|MS_RDONLY, "mode=755");
|
||
}
|
||
|
||
static int mount_unified_cgroups(const char *dest) {
|
||
const char *p;
|
||
int r;
|
||
|
||
assert(dest);
|
||
|
||
p = prefix_roota(dest, "/sys/fs/cgroup");
|
||
|
||
(void) mkdir_p(p, 0755);
|
||
|
||
r = path_is_mount_point(p, dest, AT_SYMLINK_FOLLOW);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to determine if %s is mounted already: %m", p);
|
||
if (r > 0) {
|
||
p = prefix_roota(dest, "/sys/fs/cgroup/cgroup.procs");
|
||
if (access(p, F_OK) >= 0)
|
||
return 0;
|
||
if (errno != ENOENT)
|
||
return log_error_errno(errno, "Failed to determine if mount point %s contains the unified cgroup hierarchy: %m", p);
|
||
|
||
log_error("%s is already mounted but not a unified cgroup hierarchy. Refusing.", p);
|
||
return -EINVAL;
|
||
}
|
||
|
||
return mount_verbose(LOG_ERR, "cgroup", p, "cgroup2", MS_NOSUID|MS_NOEXEC|MS_NODEV, NULL);
|
||
}
|
||
|
||
int mount_cgroups(
|
||
const char *dest,
|
||
CGroupUnified unified_requested,
|
||
bool userns,
|
||
uid_t uid_shift,
|
||
uid_t uid_range,
|
||
const char *selinux_apifs_context,
|
||
bool use_cgns) {
|
||
|
||
if (unified_requested >= CGROUP_UNIFIED_ALL)
|
||
return mount_unified_cgroups(dest);
|
||
if (use_cgns)
|
||
return mount_legacy_cgns_supported(dest, unified_requested, userns, uid_shift, uid_range, selinux_apifs_context);
|
||
|
||
return mount_legacy_cgns_unsupported(dest, unified_requested, userns, uid_shift, uid_range, selinux_apifs_context);
|
||
}
|
||
|
||
static int mount_systemd_cgroup_writable_one(const char *root, const char *own) {
|
||
int r;
|
||
|
||
assert(root);
|
||
assert(own);
|
||
|
||
/* Make our own cgroup a (writable) bind mount */
|
||
r = mount_verbose(LOG_ERR, own, own, NULL, MS_BIND, NULL);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
/* And then remount the systemd cgroup root read-only */
|
||
return mount_verbose(LOG_ERR, NULL, root, NULL,
|
||
MS_BIND|MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, NULL);
|
||
}
|
||
|
||
int mount_systemd_cgroup_writable(
|
||
const char *dest,
|
||
CGroupUnified unified_requested) {
|
||
|
||
_cleanup_free_ char *own_cgroup_path = NULL;
|
||
const char *root, *own;
|
||
int r;
|
||
|
||
assert(dest);
|
||
|
||
r = cg_pid_get_path(NULL, 0, &own_cgroup_path);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to determine our own cgroup path: %m");
|
||
|
||
/* If we are living in the top-level, then there's nothing to do... */
|
||
if (path_equal(own_cgroup_path, "/"))
|
||
return 0;
|
||
|
||
if (unified_requested >= CGROUP_UNIFIED_ALL) {
|
||
|
||
root = prefix_roota(dest, "/sys/fs/cgroup");
|
||
own = strjoina(root, own_cgroup_path);
|
||
|
||
} else {
|
||
|
||
if (unified_requested >= CGROUP_UNIFIED_SYSTEMD) {
|
||
root = prefix_roota(dest, "/sys/fs/cgroup/unified");
|
||
own = strjoina(root, own_cgroup_path);
|
||
|
||
r = mount_systemd_cgroup_writable_one(root, own);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
root = prefix_roota(dest, "/sys/fs/cgroup/systemd");
|
||
own = strjoina(root, own_cgroup_path);
|
||
}
|
||
|
||
return mount_systemd_cgroup_writable_one(root, own);
|
||
}
|
||
|
||
int setup_volatile_state(
|
||
const char *directory,
|
||
VolatileMode mode,
|
||
bool userns, uid_t uid_shift, uid_t uid_range,
|
||
const char *selinux_apifs_context) {
|
||
|
||
_cleanup_free_ char *buf = NULL;
|
||
const char *p, *options;
|
||
int r;
|
||
|
||
assert(directory);
|
||
|
||
if (mode != VOLATILE_STATE)
|
||
return 0;
|
||
|
||
/* --volatile=state means we simply overmount /var
|
||
with a tmpfs, and the rest read-only. */
|
||
|
||
r = bind_remount_recursive(directory, true, NULL);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to remount %s read-only: %m", directory);
|
||
|
||
p = prefix_roota(directory, "/var");
|
||
r = mkdir(p, 0755);
|
||
if (r < 0 && errno != EEXIST)
|
||
return log_error_errno(errno, "Failed to create %s: %m", directory);
|
||
|
||
options = "mode=755";
|
||
r = tmpfs_patch_options(options, userns, uid_shift, uid_range, false, selinux_apifs_context, &buf);
|
||
if (r < 0)
|
||
return log_oom();
|
||
if (r > 0)
|
||
options = buf;
|
||
|
||
return mount_verbose(LOG_ERR, "tmpfs", p, "tmpfs", MS_STRICTATIME, options);
|
||
}
|
||
|
||
int setup_volatile(
|
||
const char *directory,
|
||
VolatileMode mode,
|
||
bool userns, uid_t uid_shift, uid_t uid_range,
|
||
const char *selinux_apifs_context) {
|
||
|
||
bool tmpfs_mounted = false, bind_mounted = false;
|
||
char template[] = "/tmp/nspawn-volatile-XXXXXX";
|
||
_cleanup_free_ char *buf = NULL;
|
||
const char *f, *t, *options;
|
||
int r;
|
||
|
||
assert(directory);
|
||
|
||
if (mode != VOLATILE_YES)
|
||
return 0;
|
||
|
||
/* --volatile=yes means we mount a tmpfs to the root dir, and
|
||
the original /usr to use inside it, and that read-only. */
|
||
|
||
if (!mkdtemp(template))
|
||
return log_error_errno(errno, "Failed to create temporary directory: %m");
|
||
|
||
options = "mode=755";
|
||
r = tmpfs_patch_options(options, userns, uid_shift, uid_range, false, selinux_apifs_context, &buf);
|
||
if (r < 0)
|
||
return log_oom();
|
||
if (r > 0)
|
||
options = buf;
|
||
|
||
r = mount_verbose(LOG_ERR, "tmpfs", template, "tmpfs", MS_STRICTATIME, options);
|
||
if (r < 0)
|
||
goto fail;
|
||
|
||
tmpfs_mounted = true;
|
||
|
||
f = prefix_roota(directory, "/usr");
|
||
t = prefix_roota(template, "/usr");
|
||
|
||
r = mkdir(t, 0755);
|
||
if (r < 0 && errno != EEXIST) {
|
||
r = log_error_errno(errno, "Failed to create %s: %m", t);
|
||
goto fail;
|
||
}
|
||
|
||
r = mount_verbose(LOG_ERR, f, t, NULL, MS_BIND|MS_REC, NULL);
|
||
if (r < 0)
|
||
goto fail;
|
||
|
||
bind_mounted = true;
|
||
|
||
r = bind_remount_recursive(t, true, NULL);
|
||
if (r < 0) {
|
||
log_error_errno(r, "Failed to remount %s read-only: %m", t);
|
||
goto fail;
|
||
}
|
||
|
||
r = mount_verbose(LOG_ERR, template, directory, NULL, MS_MOVE, NULL);
|
||
if (r < 0)
|
||
goto fail;
|
||
|
||
(void) rmdir(template);
|
||
|
||
return 0;
|
||
|
||
fail:
|
||
if (bind_mounted)
|
||
(void) umount_verbose(t);
|
||
|
||
if (tmpfs_mounted)
|
||
(void) umount_verbose(template);
|
||
(void) rmdir(template);
|
||
return r;
|
||
}
|
||
|
||
/* Expects *pivot_root_new and *pivot_root_old to be initialised to allocated memory or NULL. */
|
||
int pivot_root_parse(char **pivot_root_new, char **pivot_root_old, const char *s) {
|
||
_cleanup_free_ char *root_new = NULL, *root_old = NULL;
|
||
const char *p = s;
|
||
int r;
|
||
|
||
assert(pivot_root_new);
|
||
assert(pivot_root_old);
|
||
|
||
r = extract_first_word(&p, &root_new, ":", EXTRACT_DONT_COALESCE_SEPARATORS);
|
||
if (r < 0)
|
||
return r;
|
||
if (r == 0)
|
||
return -EINVAL;
|
||
|
||
if (isempty(p))
|
||
root_old = NULL;
|
||
else {
|
||
root_old = strdup(p);
|
||
if (!root_old)
|
||
return -ENOMEM;
|
||
}
|
||
|
||
if (!path_is_absolute(root_new))
|
||
return -EINVAL;
|
||
if (root_old && !path_is_absolute(root_old))
|
||
return -EINVAL;
|
||
|
||
free_and_replace(*pivot_root_new, root_new);
|
||
free_and_replace(*pivot_root_old, root_old);
|
||
|
||
return 0;
|
||
}
|
||
|
||
int setup_pivot_root(const char *directory, const char *pivot_root_new, const char *pivot_root_old) {
|
||
_cleanup_free_ char *directory_pivot_root_new = NULL;
|
||
_cleanup_free_ char *pivot_tmp_pivot_root_old = NULL;
|
||
char pivot_tmp[] = "/tmp/nspawn-pivot-XXXXXX";
|
||
bool remove_pivot_tmp = false;
|
||
int r;
|
||
|
||
assert(directory);
|
||
|
||
if (!pivot_root_new)
|
||
return 0;
|
||
|
||
/* Pivot pivot_root_new to / and the existing / to pivot_root_old.
|
||
* If pivot_root_old is NULL, the existing / disappears.
|
||
* This requires a temporary directory, pivot_tmp, which is
|
||
* not a child of either.
|
||
*
|
||
* This is typically used for OSTree-style containers, where
|
||
* the root partition contains several sysroots which could be
|
||
* run. Normally, one would be chosen by the bootloader and
|
||
* pivoted to / by initramfs.
|
||
*
|
||
* For example, for an OSTree deployment, pivot_root_new
|
||
* would be: /ostree/deploy/$os/deploy/$checksum. Note that this
|
||
* code doesn’t do the /var mount which OSTree expects: use
|
||
* --bind +/sysroot/ostree/deploy/$os/var:/var for that.
|
||
*
|
||
* So in the OSTree case, we’ll end up with something like:
|
||
* - directory = /tmp/nspawn-root-123456
|
||
* - pivot_root_new = /ostree/deploy/os/deploy/123abc
|
||
* - pivot_root_old = /sysroot
|
||
* - directory_pivot_root_new =
|
||
* /tmp/nspawn-root-123456/ostree/deploy/os/deploy/123abc
|
||
* - pivot_tmp = /tmp/nspawn-pivot-123456
|
||
* - pivot_tmp_pivot_root_old = /tmp/nspawn-pivot-123456/sysroot
|
||
*
|
||
* Requires all file systems at directory and below to be mounted
|
||
* MS_PRIVATE or MS_SLAVE so they can be moved.
|
||
*/
|
||
directory_pivot_root_new = prefix_root(directory, pivot_root_new);
|
||
|
||
/* Remount directory_pivot_root_new to make it movable. */
|
||
r = mount_verbose(LOG_ERR, directory_pivot_root_new, directory_pivot_root_new, NULL, MS_BIND, NULL);
|
||
if (r < 0)
|
||
goto done;
|
||
|
||
if (pivot_root_old) {
|
||
if (!mkdtemp(pivot_tmp)) {
|
||
r = log_error_errno(errno, "Failed to create temporary directory: %m");
|
||
goto done;
|
||
}
|
||
|
||
remove_pivot_tmp = true;
|
||
pivot_tmp_pivot_root_old = prefix_root(pivot_tmp, pivot_root_old);
|
||
|
||
r = mount_verbose(LOG_ERR, directory_pivot_root_new, pivot_tmp, NULL, MS_MOVE, NULL);
|
||
if (r < 0)
|
||
goto done;
|
||
|
||
r = mount_verbose(LOG_ERR, directory, pivot_tmp_pivot_root_old, NULL, MS_MOVE, NULL);
|
||
if (r < 0)
|
||
goto done;
|
||
|
||
r = mount_verbose(LOG_ERR, pivot_tmp, directory, NULL, MS_MOVE, NULL);
|
||
if (r < 0)
|
||
goto done;
|
||
} else {
|
||
r = mount_verbose(LOG_ERR, directory_pivot_root_new, directory, NULL, MS_MOVE, NULL);
|
||
if (r < 0)
|
||
goto done;
|
||
}
|
||
|
||
done:
|
||
if (remove_pivot_tmp)
|
||
(void) rmdir(pivot_tmp);
|
||
|
||
return r;
|
||
}
|