pmempool info: different outputs when run on unaccessible parts (in sense of permissions)

[dsciebu]

Let's consider the following poolset file:

PMEMPOOLSET
AUTO /dev/dax0.0
AUTO /dev/dax1.0
OPTION SINGLEHDR

Existence of poolset option is optional :) (with or without it the result is the same).

After creating the poolset file you:

1. (as root) create poolset with pmempool create obj/blk/log (no difference) e.g.
   pmempool create blk 512 /home/nuser/pool.set
2. change access permissions of a single part (to 662 or 664) e.g.
   chmod 662 /dev/dax0.0
3. as another user, run pmempool info on the poolset file e.g.
   runuser -l nuser -c "pmempool info /home/nuser/pool.set"

The sample course:

linux:~/test # chmod 664 /dev/dax1.0
linux:~/test # ll /dev | grep dax
crw-rw-rw- 1 root root    250,   0 Feb  8 11:40 dax0.0
crw-rw-r-- 1 root root    250,   1 Feb  8 11:40 dax1.0
linux:~/test # runuser -l nuser -c "pmempool info /home/nuser/pool.set"
error: opening poolset failed
/home/nuser/pool.set: Permission denied

linux:~/test # chmod 662 /dev/dax1.0
linux:~/test # ll /dev | grep dax
crw-rw-rw- 1 root root    250,   0 Feb  8 11:40 dax0.0
crw-rw--w- 1 root root    250,   1 Feb  8 11:40 dax1.0
linux:~/test # runuser -l nuser -c "pmempool info /home/nuser/pool.set"
error: parsing poolset file failed
/home/nuser/pool.set: Invalid argument

As you can see, depending on part's access rights, you get different return messages from pmempool info:

• "Permission denied" if the part is read-only for "nuser" and
• "Invalid argument" if it is write-only.

Found on: pmempool 1.3+b2-919-gaac995ff0

[dsciebu]

After pulling the latest version I checked results of performing pmempool info in conditions described in issue and this is what I got:

linux:~/test # ll /dev | grep dax
crw-rw-rw- 1 root root    250,   0 Feb  8 11:40 dax0.0
crw-rw--w- 1 root root    250,   1 Feb  8 11:40 dax1.0
crw------- 1 root root    250,   3 Feb  8 11:40 dax2.0
crw------- 1 root root    250,   2 Feb  8 11:40 dax3.0
linux:~/test # runuser -l nuser -c "pmempool info /home/nuser/pool1.set"
error: parsing poolset file failed
error: /home/nuser/pool1.set: cannot determine type of pool
linux:~/test # chmod 664 /dev/dax1.0
linux:~/test # ll /dev | grep dax
crw-rw-rw- 1 root root    250,   0 Feb  8 11:40 dax0.0
crw-rw-r-- 1 root root    250,   1 Feb  8 11:40 dax1.0
crw------- 1 root root    250,   3 Feb  8 11:40 dax2.0
crw------- 1 root root    250,   2 Feb  8 11:40 dax3.0
linux:~/test # runuser -l nuser -c "pmempool info /home/nuser/pool1.set"
error: opening poolset failed
/home/nuser/pool1.set: Permission denied

Now the result is even stranger; instead of "Invalid argument" I got "cannot determine type of pool".

Checked on: pmempool 1.4-rc1-44-g82a8572f4

[kkajrewicz]

Verified on 1.4-rc4-1020-gde2c9dc7a