#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"

#ifndef TTY_GID

#define TTY_GID 5

#endif

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_NODEV, true },

{ "devpts", "/dev/pts", "devpts", "mode=620,gid=" STRINGIFY(TTY_GID), 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 },

};

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

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

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

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

NULSTR_FOREACH_PAIR(j, k, symlinks)

symlink_and_label(j, k);

return mount_cgroup_controllers();

}