Re: Using /proc/mounts in mountlist.c for linux

[James Youngman]

2011/5/31 Pádraig Brady <address@hidden>:
> On 31/05/11 01:14, James Youngman wrote:
>> On Tue, Apr 5, 2011 at 1:36 PM, Philipp Thomas <address@hidden> wrote:
>>> GNU find will not recognize file systems of type autofs on newer Linux
>>> kernels as autofs entries are only listed in /proc/mounts and mountlist.c
>>> includes glibc mntent.h which takes the _PATH_MOUNTED from paths.h and that
>>> is /etc/mtab.
>>>
>>> After a longer discussion, we (SUSE) chose to patch mountlist.c in findutils
>>> to use proc/mounts instead of /etc/mtab which fixed ou problem.
>>>
>>> Would gnulib accept the attached patch to mountlist.c?
>>
>> I don't know if this patch was accepted, but it shouldn't be.   The
>> problem is that /proc/mounts has incomplete data for /.   This will
>> break gnulib's mountlist, at least with the current form of the patch,
>> because mountlist will have an incorrect idea of the type of the root
>> filesystem.   Here's an example showing the problem:
>>
>> ~$ cat tryit.sh
>> #! /bin/sh
>> f() {
>>     echo "$1"
>>     ( ls -l /etc/mtab; find / -maxdepth 0 -printf '%p %F\n' ) |
>>     sed -e 's_^_    _'
>> }
>>
>> set -e
>> cd /etc
>> f "regular /etc/mtab"
>>
>> mv mtab mtab.old; ln -s ../proc/mounts mtab
>> f "with /proc/mounts"
>> rm mtab; mv mtab.old mtab
>> ~$ sudo sh tryit.sh
>> regular /etc/mtab
>>     -rw-r--r-- 1 root root 1869 May 30 23:53 /etc/mtab
>>     / ext3
>> with /proc/mounts
>>     lrwxrwxrwx 1 root root 14 May 31 01:12 /etc/mtab -> ../proc/mounts
>>     / rootfs
>
> Well I didn't merge it, but for more generic reasons.
> It seemed like a bit of a layering violation to me,
> and I was unsure that other users of gnulib may need
> access to /etc/mtab specific stuff (on older systems).
>
> Here is related output on my Fedora 15 system
> which does link /etc/mtab -> /proc/mounts
>
> $ df /
> Filesystem           1K-blocks      Used Available Use% Mounted on
> /dev/sdb2             13102208   3210896   9758244  25% /
> $ df -t rootfs
> Filesystem           1K-blocks      Used Available Use% Mounted on
> rootfs                13102208   3210896   9758244  25% /
> $ find / -maxdepth 0 -printf "%p %F\n"
> / rootfs

Thanks for the additional info.   I think that would be a bug in
Fedora 15, then.

James.