1159 lines
40 KiB
C
1159 lines
40 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#include <sys/mount.h>
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#include <linux/magic.h>
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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 "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 "mountpoint-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 "sort-util.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 "tmpfile-util.h"
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#include "user-util.h"
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CustomMount* custom_mount_add(CustomMount **l, size_t *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, size_t n) {
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size_t 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 CustomMount *a, const CustomMount *b) {
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int r;
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r = path_compare(a->destination, b->destination);
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if (r != 0)
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return r;
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return CMP(a->type, b->type);
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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, size_t n) {
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size_t 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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typesafe_qsort(l, n, 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_and_replace(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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STRV_FOREACH(j, m->lower) {
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char *s;
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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_and_replace(*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_and_replace(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, size_t *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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if (isempty(source))
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source = mfree(source);
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else if (!source_path_is_valid(source))
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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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if (empty_or_root(destination))
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return -EINVAL;
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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 = TAKE_PTR(source);
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m->destination = TAKE_PTR(destination);
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m->read_only = read_only;
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m->options = TAKE_PTR(opts);
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return 0;
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}
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int tmpfs_mount_parse(CustomMount **l, size_t *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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if (empty_or_root(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 = TAKE_PTR(path);
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m->options = TAKE_PTR(opts);
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return 0;
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}
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int overlay_mount_parse(CustomMount **l, size_t *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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if (empty_or_root(destination))
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return -EINVAL;
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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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m->destination = TAKE_PTR(destination);
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m->source = TAKE_PTR(upper);
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m->lower = TAKE_PTR(lower);
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m->read_only = read_only;
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return 0;
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}
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int tmpfs_patch_options(
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const char *options,
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uid_t uid_shift,
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const char *selinux_apifs_context,
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char **ret) {
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char *buf = NULL;
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if (uid_shift != UID_INVALID) {
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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;
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}
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#if HAVE_SELINUX
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if (selinux_apifs_context) {
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char *t;
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t = strjoin(strempty(options), options ? "," : "",
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"context=\"", selinux_apifs_context, "\"");
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free(buf);
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if (!t)
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return -ENOMEM;
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buf = t;
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}
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#endif
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if (!buf && options) {
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buf = strdup(options);
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if (!buf)
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return -ENOMEM;
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}
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*ret = buf;
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return !!buf;
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}
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int mount_sysfs(const char *dest, MountSettingsMask mount_settings) {
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const char *full, *top, *x;
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int r;
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unsigned long extra_flags = 0;
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top = prefix_roota(dest, "/sys");
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r = path_is_fs_type(top, SYSFS_MAGIC);
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if (r < 0)
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return log_error_errno(r, "Failed to determine filesystem type of %s: %m", top);
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/* /sys might already be mounted as sysfs by the outer child in the
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* !netns case. In this case, it's all good. Don't touch it because we
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* don't have the right to do so, see https://github.com/systemd/systemd/issues/1555.
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*/
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if (r > 0)
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return 0;
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full = prefix_roota(top, "/full");
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(void) mkdir(full, 0755);
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if (mount_settings & MOUNT_APPLY_APIVFS_RO)
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extra_flags |= MS_RDONLY;
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r = mount_verbose(LOG_ERR, "sysfs", full, "sysfs",
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MS_NOSUID|MS_NOEXEC|MS_NODEV|extra_flags, NULL);
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if (r < 0)
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return r;
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FOREACH_STRING(x, "block", "bus", "class", "dev", "devices", "kernel") {
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_cleanup_free_ char *from = NULL, *to = NULL;
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from = prefix_root(full, x);
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if (!from)
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return log_oom();
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to = prefix_root(top, x);
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if (!to)
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return log_oom();
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(void) mkdir(to, 0755);
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r = mount_verbose(LOG_ERR, from, to, NULL, MS_BIND, NULL);
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if (r < 0)
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return r;
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r = mount_verbose(LOG_ERR, NULL, to, NULL,
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MS_BIND|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT|extra_flags, NULL);
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if (r < 0)
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return r;
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}
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r = umount_verbose(full);
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if (r < 0)
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return r;
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if (rmdir(full) < 0)
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return log_error_errno(errno, "Failed to remove %s: %m", full);
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/* Create mountpoint for cgroups. Otherwise we are not allowed since we
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* remount /sys read-only.
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*/
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x = prefix_roota(top, "/fs/cgroup");
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(void) mkdir_p(x, 0755);
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return mount_verbose(LOG_ERR, NULL, top, NULL,
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MS_BIND|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT|extra_flags, NULL);
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}
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static int mkdir_userns(const char *path, mode_t mode, uid_t uid_shift) {
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int r;
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assert(path);
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r = mkdir_errno_wrapper(path, mode);
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if (r < 0 && r != -EEXIST)
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return r;
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if (uid_shift == UID_INVALID)
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return 0;
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|
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if (lchown(path, uid_shift, uid_shift) < 0)
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return -errno;
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return 0;
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}
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static int mkdir_userns_p(const char *prefix, const char *path, mode_t mode, uid_t uid_shift) {
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const char *p, *e;
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int r;
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||
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assert(path);
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||
|
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if (prefix && !path_startswith(path, prefix))
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return -ENOTDIR;
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|
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/* create every parent directory in the path, except the last component */
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p = path + strspn(path, "/");
|
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for (;;) {
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char t[strlen(path) + 1];
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||
|
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e = p + strcspn(p, "/");
|
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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, uid_shift);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
return mkdir_userns(path, mode, uid_shift);
|
||
}
|
||
|
||
int mount_all(const char *dest,
|
||
MountSettingsMask mount_settings,
|
||
uid_t uid_shift,
|
||
const char *selinux_apifs_context) {
|
||
|
||
#define PROC_INACCESSIBLE(path) \
|
||
{ NULL, (path), NULL, NULL, MS_BIND, \
|
||
MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO|MOUNT_INACCESSIBLE_REG }, /* Bind mount first ... */ \
|
||
{ NULL, (path), 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 */
|
||
|
||
#define PROC_READ_ONLY(path) \
|
||
{ (path), (path), NULL, NULL, MS_BIND, \
|
||
MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* Bind mount first ... */ \
|
||
{ NULL, (path), NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, \
|
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MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO } /* Then, make it r/o */
|
||
|
||
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[] = {
|
||
/* First we list inner child mounts (i.e. mounts applied *after* entering user namespacing) */
|
||
{ "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 */
|
||
|
||
/* Make these files inaccessible to container payloads: they potentially leak information about kernel
|
||
* internals or the host's execution environment to the container */
|
||
PROC_INACCESSIBLE("/proc/kallsyms"),
|
||
PROC_INACCESSIBLE("/proc/kcore"),
|
||
PROC_INACCESSIBLE("/proc/keys"),
|
||
PROC_INACCESSIBLE("/proc/sysrq-trigger"),
|
||
PROC_INACCESSIBLE("/proc/timer_list"),
|
||
|
||
/* Make these directories read-only to container payloads: they show hardware information, and in some
|
||
* cases contain tunables the container really shouldn't have access to. */
|
||
PROC_READ_ONLY("/proc/acpi"),
|
||
PROC_READ_ONLY("/proc/apm"),
|
||
PROC_READ_ONLY("/proc/asound"),
|
||
PROC_READ_ONLY("/proc/bus"),
|
||
PROC_READ_ONLY("/proc/fs"),
|
||
PROC_READ_ONLY("/proc/irq"),
|
||
PROC_READ_ONLY("/proc/scsi"),
|
||
|
||
/* Then we list outer child mounts (i.e. mounts applied *before* entering user namespacing) */
|
||
{ "tmpfs", "/tmp", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV|MS_STRICTATIME,
|
||
MOUNT_FATAL|MOUNT_APPLY_TMPFS_TMP },
|
||
{ "tmpfs", "/sys", "tmpfs", "mode=555", 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 },
|
||
{ "mqueue", "/dev/mqueue", "mqueue", NULL, 0,
|
||
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
|
||
};
|
||
|
||
_cleanup_(unlink_and_freep) char *inaccessible = NULL;
|
||
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);
|
||
bool tmpfs_tmp = (mount_settings & MOUNT_APPLY_TMPFS_TMP);
|
||
size_t k;
|
||
int r;
|
||
|
||
for (k = 0; k < ELEMENTSOF(mount_table); k++) {
|
||
_cleanup_free_ char *where = NULL, *options = NULL;
|
||
const char *o, *what;
|
||
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;
|
||
|
||
if (!tmpfs_tmp && (bool)(mount_table[k].mount_settings & MOUNT_APPLY_TMPFS_TMP))
|
||
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);
|
||
|
||
if (mount_table[k].mount_settings & MOUNT_INACCESSIBLE_REG) {
|
||
|
||
if (!inaccessible) {
|
||
_cleanup_free_ char *np = NULL;
|
||
|
||
r = tempfn_random_child(NULL, "inaccessible", &np);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to generate inaccessible file node path: %m");
|
||
|
||
r = touch_file(np, false, USEC_INFINITY, UID_INVALID, GID_INVALID, 0000);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to create inaccessible file node '%s': %m", np);
|
||
|
||
inaccessible = TAKE_PTR(np);
|
||
}
|
||
|
||
what = inaccessible;
|
||
} else
|
||
what = mount_table[k].what;
|
||
|
||
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 (what && r > 0)
|
||
continue;
|
||
|
||
r = mkdir_userns_p(dest, where, 0755, (use_userns && !in_userns) ? uid_shift : UID_INVALID);
|
||
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")) {
|
||
r = tmpfs_patch_options(o, in_userns ? 0 : uid_shift, selinux_apifs_context, &options);
|
||
if (r < 0)
|
||
return log_oom();
|
||
if (r > 0)
|
||
o = options;
|
||
}
|
||
|
||
r = mount_verbose(fatal ? LOG_ERR : LOG_DEBUG,
|
||
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))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
|
||
"Cannot bind mount directory %s on file %s.",
|
||
m->source, where);
|
||
|
||
if (!S_ISDIR(source_st.st_mode) && S_ISDIR(dest_st.st_mode))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
|
||
"Cannot bind mount file %s on directory %s.",
|
||
m->source, where);
|
||
|
||
} 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, uid_shift == 0 ? UID_INVALID : uid_shift, 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, size_t n,
|
||
bool userns, uid_t uid_shift, uid_t uid_range,
|
||
const char *selinux_apifs_context) {
|
||
|
||
size_t 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;
|
||
}
|
||
|
||
static int setup_volatile_state(
|
||
const char *directory,
|
||
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);
|
||
|
||
/* --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, uid_shift == 0 ? UID_INVALID : uid_shift, 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);
|
||
}
|
||
|
||
static int setup_volatile_yes(
|
||
const char *directory,
|
||
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);
|
||
|
||
/* --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, uid_shift == 0 ? UID_INVALID : uid_shift, selinux_apifs_context, &buf);
|
||
if (r < 0)
|
||
goto fail;
|
||
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;
|
||
}
|
||
|
||
static int setup_volatile_overlay(
|
||
const char *directory,
|
||
bool userns, uid_t uid_shift, uid_t uid_range,
|
||
const char *selinux_apifs_context) {
|
||
|
||
_cleanup_free_ char *buf = NULL, *escaped_directory = NULL, *escaped_upper = NULL, *escaped_work = NULL;
|
||
char template[] = "/tmp/nspawn-volatile-XXXXXX";
|
||
const char *upper, *work, *options;
|
||
bool tmpfs_mounted = false;
|
||
int r;
|
||
|
||
assert(directory);
|
||
|
||
/* --volatile=overlay means we mount an overlayfs to the root dir. */
|
||
|
||
if (!mkdtemp(template))
|
||
return log_error_errno(errno, "Failed to create temporary directory: %m");
|
||
|
||
options = "mode=755";
|
||
r = tmpfs_patch_options(options, uid_shift == 0 ? UID_INVALID : uid_shift, selinux_apifs_context, &buf);
|
||
if (r < 0)
|
||
goto finish;
|
||
if (r > 0)
|
||
options = buf;
|
||
|
||
r = mount_verbose(LOG_ERR, "tmpfs", template, "tmpfs", MS_STRICTATIME, options);
|
||
if (r < 0)
|
||
goto finish;
|
||
|
||
tmpfs_mounted = true;
|
||
|
||
upper = strjoina(template, "/upper");
|
||
work = strjoina(template, "/work");
|
||
|
||
if (mkdir(upper, 0755) < 0) {
|
||
r = log_error_errno(errno, "Failed to create %s: %m", upper);
|
||
goto finish;
|
||
}
|
||
if (mkdir(work, 0755) < 0) {
|
||
r = log_error_errno(errno, "Failed to create %s: %m", work);
|
||
goto finish;
|
||
}
|
||
|
||
/* And now, let's overmount the root dir with an overlayfs that uses the root dir as lower dir. It's kinda nice
|
||
* that the kernel allows us to do that without going through some mount point rearrangements. */
|
||
|
||
escaped_directory = shell_escape(directory, ",:");
|
||
escaped_upper = shell_escape(upper, ",:");
|
||
escaped_work = shell_escape(work, ",:");
|
||
if (!escaped_directory || !escaped_upper || !escaped_work) {
|
||
r = -ENOMEM;
|
||
goto finish;
|
||
}
|
||
|
||
options = strjoina("lowerdir=", escaped_directory, ",upperdir=", escaped_upper, ",workdir=", escaped_work);
|
||
r = mount_verbose(LOG_ERR, "overlay", directory, "overlay", 0, options);
|
||
|
||
finish:
|
||
if (tmpfs_mounted)
|
||
(void) umount_verbose(template);
|
||
|
||
(void) rmdir(template);
|
||
return r;
|
||
}
|
||
|
||
int setup_volatile_mode(
|
||
const char *directory,
|
||
VolatileMode mode,
|
||
bool userns, uid_t uid_shift, uid_t uid_range,
|
||
const char *selinux_apifs_context) {
|
||
|
||
switch (mode) {
|
||
|
||
case VOLATILE_YES:
|
||
return setup_volatile_yes(directory, userns, uid_shift, uid_range, selinux_apifs_context);
|
||
|
||
case VOLATILE_STATE:
|
||
return setup_volatile_state(directory, userns, uid_shift, uid_range, selinux_apifs_context);
|
||
|
||
case VOLATILE_OVERLAY:
|
||
return setup_volatile_overlay(directory, userns, uid_shift, uid_range, selinux_apifs_context);
|
||
|
||
default:
|
||
return 0;
|
||
}
|
||
}
|
||
|
||
/* 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;
|
||
}
|