mirror of
https://github.com/systemd/systemd.git
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870 lines
28 KiB
C
870 lines
28 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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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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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 "util.h"
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#include "rm-rf.h"
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#include "strv.h"
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#include "path-util.h"
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#include "mkdir.h"
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#include "label.h"
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#include "set.h"
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#include "cgroup-util.h"
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#include "nspawn-mount.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 = realloc(*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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strv_free(m->lower);
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}
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free(l);
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}
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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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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);
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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 (!path_is_absolute(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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m = custom_mount_add(l, n, CUSTOM_MOUNT_BIND);
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if (!m)
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return log_oom();
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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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static int tmpfs_patch_options(
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const char *options,
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bool userns, uid_t uid_shift, uid_t uid_range,
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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 (userns && uid_shift != 0) {
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assert(uid_shift != UID_INVALID);
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if (options)
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(void) asprintf(&buf, "%s,uid=" UID_FMT ",gid=" UID_FMT, options, uid_shift, uid_shift);
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else
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(void) asprintf(&buf, "uid=" UID_FMT ",gid=" UID_FMT, uid_shift, uid_shift);
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if (!buf)
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return -ENOMEM;
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options = buf;
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}
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#ifdef HAVE_SELINUX
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if (selinux_apifs_context) {
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char *t;
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if (options)
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t = strjoin(options, ",context=\"", selinux_apifs_context, "\"", NULL);
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else
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t = strjoin("context=\"", selinux_apifs_context, "\"", NULL);
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if (!t) {
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free(buf);
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return -ENOMEM;
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}
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free(buf);
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buf = t;
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}
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#endif
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*ret = buf;
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return !!buf;
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}
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int mount_all(const char *dest,
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bool userns, uid_t uid_shift, uid_t uid_range,
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const char *selinux_apifs_context) {
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typedef struct MountPoint {
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const char *what;
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const char *where;
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const char *type;
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const char *options;
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unsigned long flags;
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bool fatal;
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bool userns;
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} MountPoint;
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static const MountPoint mount_table[] = {
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{ "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, true, true },
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{ "/proc/sys", "/proc/sys", NULL, NULL, MS_BIND, true, true }, /* Bind mount first */
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{ NULL, "/proc/sys", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, true, true }, /* Then, make it r/o */
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{ "sysfs", "/sys", "sysfs", NULL, MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV, true, false },
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{ "tmpfs", "/dev", "tmpfs", "mode=755", MS_NOSUID|MS_STRICTATIME, true, false },
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{ "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV|MS_STRICTATIME, true, false },
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{ "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID|MS_NODEV|MS_STRICTATIME, true, false },
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{ "tmpfs", "/tmp", "tmpfs", "mode=1777", MS_STRICTATIME, true, false },
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#ifdef HAVE_SELINUX
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{ "/sys/fs/selinux", "/sys/fs/selinux", NULL, NULL, MS_BIND, false, false }, /* Bind mount first */
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{ NULL, "/sys/fs/selinux", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, false, false }, /* Then, make it r/o */
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#endif
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};
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unsigned k;
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int r;
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for (k = 0; k < ELEMENTSOF(mount_table); k++) {
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_cleanup_free_ char *where = NULL, *options = NULL;
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const char *o;
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if (userns != mount_table[k].userns)
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continue;
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where = prefix_root(dest, mount_table[k].where);
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if (!where)
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return log_oom();
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r = path_is_mount_point(where, AT_SYMLINK_FOLLOW);
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if (r < 0 && r != -ENOENT)
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return log_error_errno(r, "Failed to detect whether %s is a mount point: %m", where);
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/* Skip this entry if it is not a remount. */
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if (mount_table[k].what && r > 0)
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continue;
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r = mkdir_p(where, 0755);
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if (r < 0) {
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if (mount_table[k].fatal)
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return log_error_errno(r, "Failed to create directory %s: %m", where);
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log_warning_errno(r, "Failed to create directory %s: %m", where);
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continue;
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}
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o = mount_table[k].options;
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if (streq_ptr(mount_table[k].type, "tmpfs")) {
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r = tmpfs_patch_options(o, userns, uid_shift, uid_range, selinux_apifs_context, &options);
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if (r < 0)
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return log_oom();
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if (r > 0)
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o = options;
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}
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if (mount(mount_table[k].what,
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where,
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mount_table[k].type,
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mount_table[k].flags,
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o) < 0) {
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if (mount_table[k].fatal)
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return log_error_errno(errno, "mount(%s) failed: %m", where);
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log_warning_errno(errno, "mount(%s) failed, ignoring: %m", where);
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}
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}
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return 0;
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}
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static int parse_mount_bind_options(const char *options, unsigned long *mount_flags, char **mount_opts) {
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const char *p = options;
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unsigned long flags = *mount_flags;
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char *opts = NULL;
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assert(options);
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for (;;) {
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_cleanup_free_ char *word = NULL;
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int r = extract_first_word(&p, &word, ",", 0);
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if (r < 0)
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return log_error_errno(r, "Failed to extract mount option: %m");
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if (r == 0)
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break;
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if (streq(word, "rbind"))
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flags |= MS_REC;
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else if (streq(word, "norbind"))
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flags &= ~MS_REC;
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else {
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log_error("Invalid bind mount option: %s", word);
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return -EINVAL;
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}
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}
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*mount_flags = flags;
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/* in the future mount_opts will hold string options for mount(2) */
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*mount_opts = opts;
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return 0;
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}
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static int mount_bind(const char *dest, CustomMount *m) {
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struct stat source_st, dest_st;
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const char *where;
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unsigned long mount_flags = MS_BIND | MS_REC;
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_cleanup_free_ char *mount_opts = NULL;
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int r;
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assert(m);
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if (m->options) {
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r = parse_mount_bind_options(m->options, &mount_flags, &mount_opts);
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if (r < 0)
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return r;
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}
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if (stat(m->source, &source_st) < 0)
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return log_error_errno(errno, "Failed to stat %s: %m", m->source);
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where = prefix_roota(dest, m->destination);
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if (stat(where, &dest_st) >= 0) {
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if (S_ISDIR(source_st.st_mode) && !S_ISDIR(dest_st.st_mode)) {
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log_error("Cannot bind mount directory %s on file %s.", m->source, where);
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return -EINVAL;
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}
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if (!S_ISDIR(source_st.st_mode) && S_ISDIR(dest_st.st_mode)) {
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log_error("Cannot bind mount file %s on directory %s.", m->source, where);
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return -EINVAL;
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}
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} else if (errno == ENOENT) {
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r = mkdir_parents_label(where, 0755);
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if (r < 0)
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return log_error_errno(r, "Failed to make parents of %s: %m", where);
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} else {
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log_error_errno(errno, "Failed to stat %s: %m", where);
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return -errno;
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}
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/* Create the mount point. Any non-directory file can be
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* mounted on any non-directory file (regular, fifo, socket,
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* char, block).
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*/
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if (S_ISDIR(source_st.st_mode))
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r = mkdir_label(where, 0755);
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else
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r = touch(where);
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if (r < 0 && r != -EEXIST)
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return log_error_errno(r, "Failed to create mount point %s: %m", where);
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if (mount(m->source, where, NULL, mount_flags, mount_opts) < 0)
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return log_error_errno(errno, "mount(%s) failed: %m", where);
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if (m->read_only) {
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r = bind_remount_recursive(where, true);
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if (r < 0)
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return log_error_errno(r, "Read-only bind mount failed: %m");
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}
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return 0;
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}
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static int mount_tmpfs(
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const char *dest,
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CustomMount *m,
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bool userns, uid_t uid_shift, uid_t uid_range,
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const char *selinux_apifs_context) {
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const char *where, *options;
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_cleanup_free_ char *buf = NULL;
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int r;
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assert(dest);
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assert(m);
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where = prefix_roota(dest, m->destination);
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r = mkdir_p_label(where, 0755);
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if (r < 0 && r != -EEXIST)
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return log_error_errno(r, "Creating mount point for tmpfs %s failed: %m", where);
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r = tmpfs_patch_options(m->options, userns, uid_shift, uid_range, selinux_apifs_context, &buf);
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if (r < 0)
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return log_oom();
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options = r > 0 ? buf : m->options;
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if (mount("tmpfs", where, "tmpfs", MS_NODEV|MS_STRICTATIME, options) < 0)
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return log_error_errno(errno, "tmpfs mount to %s failed: %m", where);
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return 0;
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}
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static char *joined_and_escaped_lower_dirs(char * const *lower) {
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_cleanup_strv_free_ char **sv = NULL;
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sv = strv_copy(lower);
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if (!sv)
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return NULL;
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strv_reverse(sv);
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if (!strv_shell_escape(sv, ",:"))
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return NULL;
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return strv_join(sv, ":");
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}
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static int mount_overlay(const char *dest, CustomMount *m) {
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_cleanup_free_ char *lower = NULL;
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const char *where, *options;
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int r;
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assert(dest);
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assert(m);
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where = prefix_roota(dest, m->destination);
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r = mkdir_label(where, 0755);
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if (r < 0 && r != -EEXIST)
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return log_error_errno(r, "Creating mount point for overlay %s failed: %m", where);
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(void) mkdir_p_label(m->source, 0755);
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lower = joined_and_escaped_lower_dirs(m->lower);
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if (!lower)
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return log_oom();
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if (m->read_only) {
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_cleanup_free_ char *escaped_source = NULL;
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escaped_source = shell_escape(m->source, ",:");
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if (!escaped_source)
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return log_oom();
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options = strjoina("lowerdir=", escaped_source, ":", lower);
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} else {
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_cleanup_free_ char *escaped_source = NULL, *escaped_work_dir = NULL;
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assert(m->work_dir);
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(void) mkdir_label(m->work_dir, 0700);
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escaped_source = shell_escape(m->source, ",:");
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if (!escaped_source)
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return log_oom();
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escaped_work_dir = shell_escape(m->work_dir, ",:");
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if (!escaped_work_dir)
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return log_oom();
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options = strjoina("lowerdir=", lower, ",upperdir=", escaped_source, ",workdir=", escaped_work_dir);
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}
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if (mount("overlay", where, "overlay", m->read_only ? MS_RDONLY : 0, options) < 0)
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return log_error_errno(errno, "overlay mount to %s failed: %m", where);
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return 0;
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}
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int mount_custom(
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const char *dest,
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CustomMount *mounts, unsigned n,
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bool userns, uid_t uid_shift, uid_t uid_range,
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const char *selinux_apifs_context) {
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unsigned i;
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int r;
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assert(dest);
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for (i = 0; i < n; i++) {
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CustomMount *m = mounts + i;
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switch (m->type) {
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case CUSTOM_MOUNT_BIND:
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r = mount_bind(dest, m);
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break;
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case CUSTOM_MOUNT_TMPFS:
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r = mount_tmpfs(dest, m, userns, uid_shift, uid_range, selinux_apifs_context);
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break;
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case CUSTOM_MOUNT_OVERLAY:
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r = mount_overlay(dest, m);
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break;
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default:
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assert_not_reached("Unknown custom mount type");
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}
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if (r < 0)
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return r;
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}
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return 0;
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}
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static int mount_legacy_cgroup_hierarchy(const char *dest, const char *controller, const char *hierarchy, bool read_only) {
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char *to;
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|
int r;
|
|
|
|
to = strjoina(dest, "/sys/fs/cgroup/", hierarchy);
|
|
|
|
r = path_is_mount_point(to, 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 (mount("cgroup", to, "cgroup", MS_NOSUID|MS_NOEXEC|MS_NODEV, controller) < 0)
|
|
return log_error_errno(errno, "Failed to mount to %s: %m", to);
|
|
|
|
/* ... hence let's only make the bind mount read-only, not the
|
|
* superblock. */
|
|
if (read_only) {
|
|
if (mount(NULL, to, NULL, MS_BIND|MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, NULL) < 0)
|
|
return log_error_errno(errno, "Failed to remount %s read-only: %m", to);
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
static int mount_legacy_cgroups(
|
|
const char *dest,
|
|
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");
|
|
|
|
/* Mount a tmpfs to /sys/fs/cgroup if it's not mounted there yet. */
|
|
r = path_is_mount_point(cgroup_root, 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, selinux_apifs_context, &options);
|
|
if (r < 0)
|
|
return log_oom();
|
|
|
|
if (mount("tmpfs", cgroup_root, "tmpfs", MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME, options) < 0)
|
|
return log_error_errno(errno, "Failed to mount /sys/fs/cgroup: %m");
|
|
}
|
|
|
|
if (cg_unified() > 0)
|
|
goto skip_controllers;
|
|
|
|
controllers = set_new(&string_hash_ops);
|
|
if (!controllers)
|
|
return log_oom();
|
|
|
|
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) {
|
|
log_error("Invalid existing symlink for combined hierarchy");
|
|
return r;
|
|
}
|
|
if (r < 0)
|
|
return log_error_errno(r, "Failed to create symlink for combined hierarchy: %m");
|
|
}
|
|
}
|
|
|
|
skip_controllers:
|
|
r = mount_legacy_cgroup_hierarchy(dest, "none,name=systemd,xattr", "systemd", false);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
if (mount(NULL, cgroup_root, NULL, MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME|MS_RDONLY, "mode=755") < 0)
|
|
return log_error_errno(errno, "Failed to remount %s read-only: %m", cgroup_root);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int mount_unified_cgroups(const char *dest) {
|
|
const char *p;
|
|
int r;
|
|
|
|
assert(dest);
|
|
|
|
p = strjoina(dest, "/sys/fs/cgroup");
|
|
|
|
r = path_is_mount_point(p, 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 = strjoina(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;
|
|
}
|
|
|
|
if (mount("cgroup", p, "cgroup", MS_NOSUID|MS_NOEXEC|MS_NODEV, "__DEVEL__sane_behavior") < 0)
|
|
return log_error_errno(errno, "Failed to mount unified cgroup hierarchy to %s: %m", p);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int mount_cgroups(
|
|
const char *dest,
|
|
bool unified_requested,
|
|
bool userns, uid_t uid_shift, uid_t uid_range,
|
|
const char *selinux_apifs_context) {
|
|
|
|
if (unified_requested)
|
|
return mount_unified_cgroups(dest);
|
|
else
|
|
return mount_legacy_cgroups(dest, userns, uid_shift, uid_range, selinux_apifs_context);
|
|
}
|
|
|
|
int mount_systemd_cgroup_writable(
|
|
const char *dest,
|
|
bool unified_requested) {
|
|
|
|
_cleanup_free_ char *own_cgroup_path = NULL;
|
|
const char *systemd_root, *systemd_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) {
|
|
systemd_own = strjoina(dest, "/sys/fs/cgroup", own_cgroup_path);
|
|
systemd_root = prefix_roota(dest, "/sys/fs/cgroup");
|
|
} else {
|
|
systemd_own = strjoina(dest, "/sys/fs/cgroup/systemd", own_cgroup_path);
|
|
systemd_root = prefix_roota(dest, "/sys/fs/cgroup/systemd");
|
|
}
|
|
|
|
/* Make our own cgroup a (writable) bind mount */
|
|
if (mount(systemd_own, systemd_own, NULL, MS_BIND, NULL) < 0)
|
|
return log_error_errno(errno, "Failed to turn %s into a bind mount: %m", own_cgroup_path);
|
|
|
|
/* And then remount the systemd cgroup root read-only */
|
|
if (mount(NULL, systemd_root, NULL, MS_BIND|MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, NULL) < 0)
|
|
return log_error_errno(errno, "Failed to mount cgroup root read-only: %m");
|
|
|
|
return 0;
|
|
}
|
|
|
|
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);
|
|
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, selinux_apifs_context, &buf);
|
|
if (r < 0)
|
|
return log_oom();
|
|
if (r > 0)
|
|
options = buf;
|
|
|
|
if (mount("tmpfs", p, "tmpfs", MS_STRICTATIME, options) < 0)
|
|
return log_error_errno(errno, "Failed to mount tmpfs to /var: %m");
|
|
|
|
return 0;
|
|
}
|
|
|
|
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, selinux_apifs_context, &buf);
|
|
if (r < 0)
|
|
return log_oom();
|
|
if (r > 0)
|
|
options = buf;
|
|
|
|
if (mount("tmpfs", template, "tmpfs", MS_STRICTATIME, options) < 0) {
|
|
r = log_error_errno(errno, "Failed to mount tmpfs for root directory: %m");
|
|
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;
|
|
}
|
|
|
|
if (mount(f, t, NULL, MS_BIND|MS_REC, NULL) < 0) {
|
|
r = log_error_errno(errno, "Failed to create /usr bind mount: %m");
|
|
goto fail;
|
|
}
|
|
|
|
bind_mounted = true;
|
|
|
|
r = bind_remount_recursive(t, true);
|
|
if (r < 0) {
|
|
log_error_errno(r, "Failed to remount %s read-only: %m", t);
|
|
goto fail;
|
|
}
|
|
|
|
if (mount(template, directory, NULL, MS_MOVE, NULL) < 0) {
|
|
r = log_error_errno(errno, "Failed to move root mount: %m");
|
|
goto fail;
|
|
}
|
|
|
|
(void) rmdir(template);
|
|
|
|
return 0;
|
|
|
|
fail:
|
|
if (bind_mounted)
|
|
(void) umount(t);
|
|
|
|
if (tmpfs_mounted)
|
|
(void) umount(template);
|
|
(void) rmdir(template);
|
|
return r;
|
|
}
|
|
|
|
VolatileMode volatile_mode_from_string(const char *s) {
|
|
int b;
|
|
|
|
if (isempty(s))
|
|
return _VOLATILE_MODE_INVALID;
|
|
|
|
b = parse_boolean(s);
|
|
if (b > 0)
|
|
return VOLATILE_YES;
|
|
if (b == 0)
|
|
return VOLATILE_NO;
|
|
|
|
if (streq(s, "state"))
|
|
return VOLATILE_STATE;
|
|
|
|
return _VOLATILE_MODE_INVALID;
|
|
}
|