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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <sys/mount.h>
#include <errno.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <string.h>
#include <libgen.h>
#include <assert.h>
#include <unistd.h>
#include <ftw.h>
#include "mount-setup.h"
#include "log.h"
#include "macro.h"
#include "util.h"
#include "label.h"
typedef struct MountPoint {
const char *what;
const char *where;
const char *type;
const char *options;
unsigned long flags;
bool fatal;
} MountPoint;
static const MountPoint mount_table[] = {
{ "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, true },
{ "sysfs", "/sys", "sysfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, true },
{ "devtmpfs", "/dev", "devtmpfs", "mode=755", MS_NOSUID, true },
{ "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID|MS_NOEXEC|MS_NODEV, true },
{ "devpts", "/dev/pts", "devpts", NULL, MS_NOSUID|MS_NOEXEC, false },
{ "tmpfs", "/sys/fs/cgroup", "tmpfs", "mode=755", MS_NOSUID|MS_NOEXEC|MS_NODEV, true },
{ "cgroup", "/sys/fs/cgroup/systemd", "cgroup", "none,name=systemd", MS_NOSUID|MS_NOEXEC|MS_NODEV, true },
};
/* These are API file systems that might be mounted by other software,
* we just list them here so that we know that we should ignore them */
static const char * const ignore_paths[] = {
"/selinux",
"/proc/bus/usb",
"/var/lib/nfs/rpc_pipefs",
"/proc/fs/nfsd"
};
bool mount_point_is_api(const char *path) {
unsigned i;
/* Checks if this mount point is considered "API", and hence
* should be ignored */
for (i = 0; i < ELEMENTSOF(mount_table); i ++)
if (path_equal(path, mount_table[i].where))
return true;
return path_startswith(path, "/sys/fs/cgroup/");
}
bool mount_point_ignore(const char *path) {
unsigned i;
for (i = 0; i < ELEMENTSOF(ignore_paths); i++)
if (path_equal(path, ignore_paths[i]))
return true;
return false;
}
static int mount_one(const MountPoint *p) {
int r;
assert(p);
if ((r = path_is_mount_point(p->where)) < 0)
return r;
if (r > 0)
return 0;
/* The access mode here doesn't really matter too much, since
* the mounted file system will take precedence anyway. */
mkdir_p(p->where, 0755);
log_debug("Mounting %s to %s of type %s with options %s.",
p->what,
p->where,
p->type,
strna(p->options));
if (mount(p->what,
p->where,
p->type,
p->flags,
p->options) < 0) {
log_error("Failed to mount %s: %s", p->where, strerror(errno));
return p->fatal ? -errno : 0;
}
label_fix(p->where);
return 0;
}
static int mount_cgroup_controllers(void) {
int r;
FILE *f;
char buf [256];
/* Mount all available cgroup controllers that are built into the kernel. */
if (!(f = fopen("/proc/cgroups", "re")))
return -ENOENT;
/* Ignore the header line */
(void) fgets(buf, sizeof(buf), f);
for (;;) {
MountPoint p;
char *controller, *where;
int enabled = false;
if (fscanf(f, "%ms %*i %*i %i", &controller, &enabled) != 2) {
if (feof(f))
break;
log_error("Failed to parse /proc/cgroups.");
r = -EIO;
goto finish;
}
if (!enabled) {
free(controller);
continue;
}
if (asprintf(&where, "/sys/fs/cgroup/%s", controller) < 0) {
free(controller);
r = -ENOMEM;
goto finish;
}
zero(p);
p.what = "cgroup";
p.where = where;
p.type = "cgroup";
p.options = controller;
p.flags = MS_NOSUID|MS_NOEXEC|MS_NODEV;
p.fatal = false;
r = mount_one(&p);
free(controller);
free(where);
if (r < 0)
goto finish;
}
r = 0;
finish:
fclose(f);
return r;
}
static int symlink_and_label(const char *old_path, const char *new_path) {
int r;
assert(old_path);
assert(new_path);
if ((r = label_symlinkfile_set(new_path)) < 0)
return r;
if (symlink(old_path, new_path) < 0)
r = -errno;
label_file_clear();
return r;
}
static int nftw_cb(
const char *fpath,
const struct stat *sb,
int tflag,
struct FTW *ftwbuf) {
/* No need to label /dev twice in a row... */
if (ftwbuf->level == 0)
return 0;
label_fix(fpath);
return 0;
};
int mount_setup(void) {
const char symlinks[] =
"/proc/kcore\0" "/dev/core\0"
"/proc/self/fd\0" "/dev/fd\0"
"/proc/self/fd/0\0" "/dev/stdin\0"
"/proc/self/fd/1\0" "/dev/stdout\0"
"/proc/self/fd/2\0" "/dev/stderr\0"
"\0";
int r;
unsigned i;
const char *j, *k;
for (i = 0; i < ELEMENTSOF(mount_table); i ++)
if ((r = mount_one(mount_table+i)) < 0)
return r;
/* Nodes in devtmpfs need to be manually updated for the
* appropriate labels, after mounting. The other virtual API
* file systems do not need. */
if (unlink("/dev/.systemd/relabel-devtmpfs") >= 0)
nftw("/dev", nftw_cb, 64, FTW_MOUNT|FTW_PHYS);
/* Create a few default symlinks, which are normally created
* bei udevd, but some scripts might need them before we start
* udevd. */
NULSTR_FOREACH_PAIR(j, k, symlinks)
symlink_and_label(j, k);
return mount_cgroup_controllers();
}
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