static int
path_is_on_readonly_fs (char *path)
{
struct statvfs stvfsbuf;
if (statvfs (path, &stvfsbuf) == -1)
{
perrorv ("statvfs(%s): ", path);
exit (1);
}
return (stvfsbuf.f_flag & ST_RDONLY) != 0;
}
int
main(int argc, char *argv[])
{
const char *remounts[] = { "/sysroot", "/etc", "/home", "/root", "/tmp", "/var", NULL };
struct stat stbuf;
int i;
if (path_is_on_readonly_fs ("/"))
{
/* If / isn't writable, don't do any remounts; we don't want
* to clear the readonly flag in that case.
*/
maybe_mount_tmpfs_on_var ();
exit (0);
}
for (i = 0; remounts[i] != NULL; i++)
{
const char *target = remounts[i];
if (lstat (target, &stbuf) < 0)
continue;
/* Silently ignore symbolic links; we expect these to point to
* /sysroot, and thus there isn't a bind mount there.
*/
if (S_ISLNK (stbuf.st_mode))
continue;
if (mount (target, target, NULL, MS_REMOUNT | MS_SILENT, NULL) < 0)
{
/* Also ignore ENINVAL - if the target isn't a mountpoint
* already, then assume things are OK.
*/
if (errno != EINVAL)
{
perrorv ("failed to remount %s", target);
exit (1);
}
}
}
maybe_mount_tmpfs_on_var ();
exit (0);
}
int
main(int argc, char *argv[])
{
const char *readonly_bind_mounts[] = { "/usr", NULL };
const char *root_mountpoint = NULL;
char *ostree_target = NULL;
char *deploy_path = NULL;
char srcpath[PATH_MAX];
char destpath[PATH_MAX];
struct stat stbuf;
int i;
if (argc < 2)
{
fprintf (stderr, "usage: ostree-prepare-root SYSROOT\n");
exit (1);
}
root_mountpoint = argv[1];
ostree_target = parse_ostree_cmdline ();
if (!ostree_target)
{
fprintf (stderr, "No OSTree target; expected ostree=/ostree/boot.N/...\n");
exit (1);
}
snprintf (destpath, sizeof(destpath), "%s/%s", root_mountpoint, ostree_target);
fprintf (stderr, "Examining %s\n", destpath);
if (lstat (destpath, &stbuf) < 0)
{
perrorv ("Couldn't find specified OSTree root '%s': ", destpath);
exit (1);
}
if (!S_ISLNK (stbuf.st_mode))
{
fprintf (stderr, "OSTree target is not a symbolic link: %s\n", destpath);
exit (1);
}
deploy_path = realpath (destpath, NULL);
if (deploy_path == NULL)
{
perrorv ("realpath(%s) failed: ", destpath);
exit (1);
}
fprintf (stderr, "Resolved OSTree target to: %s\n", deploy_path);
/* Work-around for a kernel bug: for some reason the kernel
* refuses switching root if any file systems are mounted
* MS_SHARED. Hence remount them MS_PRIVATE here as a
* work-around.
*
* https://bugzilla.redhat.com/show_bug.cgi?id=847418 */
if (mount (NULL, "/", NULL, MS_REC|MS_PRIVATE, NULL) < 0)
{
perrorv ("Failed to make \"/\" private mount: %m");
exit (1);
}
/* Make deploy_path a bind mount, so we can move it later */
if (mount (deploy_path, deploy_path, NULL, MS_BIND, NULL) < 0)
{
perrorv ("failed to initial bind mount %s", deploy_path);
exit (1);
}
snprintf (destpath, sizeof(destpath), "%s/sysroot", deploy_path);
if (mount (root_mountpoint, destpath, NULL, MS_BIND, NULL) < 0)
{
perrorv ("Failed to bind mount %s to '%s'", root_mountpoint, destpath);
exit (1);
}
snprintf (srcpath, sizeof(srcpath), "%s/../../var", deploy_path);
snprintf (destpath, sizeof(destpath), "%s/var", deploy_path);
if (mount (srcpath, destpath, NULL, MS_MGC_VAL|MS_BIND, NULL) < 0)
{
perrorv ("failed to bind mount %s to %s", srcpath, destpath);
exit (1);
}
for (i = 0; readonly_bind_mounts[i] != NULL; i++)
{
snprintf (destpath, sizeof(destpath), "%s%s", deploy_path, readonly_bind_mounts[i]);
if (mount (destpath, destpath, NULL, MS_BIND, NULL) < 0)
{
perrorv ("failed to bind mount (class:readonly) %s", destpath);
exit (1);
}
if (mount (destpath, destpath, NULL, MS_BIND | MS_REMOUNT | MS_RDONLY, NULL) < 0)
{
perrorv ("failed to bind mount (class:readonly) %s", destpath);
exit (1);
}
}
/* This is a bit hacky - move our deployment to /sysroot, since
* systemd's initrd-switch-root target hardcodes looking for it
* there.
*/
if (mount (deploy_path, root_mountpoint, NULL, MS_MOVE, NULL) < 0)
{
perrorv ("failed to MS_MOVE %s to %s", deploy_path, root_mountpoint);
exit (1);
}
exit (0);
}
