util-linux/mount.c : lstat / stat ?

[Denis Vlasenko]

On Thursday 17 May 2007 12:05, Yann Le Doaré wrote:
> Hi,
> 
> I had to replace lstat with stat in util-linux/mount.c (Busybox 1.4.2) 
> to make mount works with symbolics links.

Can you elaborate a bit more. I see only one lstat(), here:


        // Look at the file.  (Not found isn't a failure for remount, or for
        // a synthetic filesystem like proc or sysfs.)

        if (!lstat(mp->mnt_fsname, &st)
         && !(vfsflags & (MS_REMOUNT | MS_BIND | MS_MOVE))
        ) {
                // Do we need to allocate a loopback device for it?

                if (ENABLE_FEATURE_MOUNT_LOOP && S_ISREG(st.st_mode)) {
                        loopFile = bb_simplify_path(mp->mnt_fsname);
                        mp->mnt_fsname = 0;
                        switch (set_loop(&(mp->mnt_fsname), loopFile, 0)) {
                        case 0:
                        case 1:
                                break;
                        default:
                                bb_error_msg( errno == EPERM || errno == EACCES
                                        ? bb_msg_perm_denied_are_you_root
                                        : "cannot setup loop device");
                                return errno;
                        }

                // Autodetect bind mounts

                } else if (S_ISDIR(st.st_mode) && !mp->mnt_type)
                        vfsflags |= MS_BIND;
        }

> (The patch svn-15788.patch was used to fix it in busybox 1.2.1)

adding/removing/adding of fixes happens when some not obvious
code lacks good comment. In this piece of code, for example,
I wouldn't see immediately whether we need stat or lstat.
--
vda