bug#37702: Suggestion for 'df' utility

[Bernhard Voelker]

On 2020-05-31 01:07, Paul Eggert wrote:
> On 5/30/20 4:49 AM, Erik Auerswald wrote:
>> I concur that a command line option to override config file (or env var)
>> settings seems useful if a config file and/or env var approach is used.

Just to mention another alternative to control the behavior besides env 
variables or
config files: it would theoretically also be possible to add a './configure' 
option
to add more file system types to the list of pseudofilesystems at build time.
Obviously, such idea moves the responsibility to the packager - which is not
nice either.

> In other utilities we've been moving away from environment variables and/or
> config files for the usual security and other-hassle reasons. So I'd prefer
> having 'df' just do the "right" thing by default, and to have an option to
> override that. The "right" thing should be to ignore all these 
> pseudofilesystems
> that hardly anybody cares about.

+1

What about to start with this?

  $ GIT_PAGER= git -C gnulib diff
  diff --git a/lib/mountlist.c b/lib/mountlist.c
  index 7abe0248e..5f6249dec 100644
  --- a/lib/mountlist.c
  +++ b/lib/mountlist.c
  @@ -164,6 +164,9 @@

   #define ME_DUMMY_0(Fs_name, Fs_type)            \
     (strcmp (Fs_type, "autofs") == 0              \
  +   || strcmp (Fs_type, "tmpfs") == 0            \
  +   || strcmp (Fs_type, "devtmpfs") == 0         \
  +   || strcmp (Fs_type, "squashfs") == 0         \
      || strcmp (Fs_type, "proc") == 0             \
      || strcmp (Fs_type, "subfs") == 0            \
      /* for Linux 2.6/3.x */                      \

Example output (here on openSUSE:Tumbleweed):

  $ src/df -Th
  Filesystem     Type  Size  Used Avail Use% Mounted on
  /dev/sda2      ext4   20G   14G  5.1G  73% /
  /dev/sda5      ext4  591G  278G  313G  48% /media/big_data
  /dev/loop0     ext2   31M   31M     0 100% /FULL_PARTITION_TMPDIR
  /dev/sda3      ext3  109G   90G   14G  87% /home

... thus omitting those mounts:

  $ diff -wu0 <(/usr/bin/df -Th) <(src/df -Th)
  --- /dev/fd/63        2020-05-31 11:30:29.991664999 +0200
  +++ /dev/fd/62        2020-05-31 11:30:29.987664947 +0200
  @@ -2,4 +1,0 @@
  -devtmpfs       devtmpfs  9.8G  8.0K  9.8G   1% /dev
  -tmpfs          tmpfs     9.8G  640K  9.8G   1% /dev/shm
  -tmpfs          tmpfs     9.8G   18M  9.8G   1% /run
  -tmpfs          tmpfs     9.8G     0  9.8G   0% /sys/fs/cgroup
  @@ -10 +5,0 @@
  -tmpfs          tmpfs     2.0G   44K  2.0G   1% /run/user/1000

Have a nice day,
Berny