Question marks in output of command "ls -la" in Ubuntu

linux, logging, ls, nginx, permissions

Solution

This issue is a permission problem. Specifically, it relates to execute bits on directories.

Consider the following example

$ mkdir -p remove_execute/remove_execute_test     
$ touch remove_execute/remove_execute_test/test_file.txt 
$ ls -la remove_execute/remove_execute_test/ 
total 8 
drwxrwxr-x 2 zerodf zerodf 4096 Nov 21 10:51 . 
drwxrwxr-x 3 zerodf zerodf 4096 Nov 21 10:51 ..
-rw-rw-r-- 1 zerodf zerodf    0 Nov 21 10:51 test_file.txt

Now, if we remove execute permission on the directory, we can't get the stats.

$ sudo chmod a-x remove_execute/remove_execute_test/ 
$ ls -la remove_execute/remove_execute_test/ 
ls: cannot access remove_execute/remove_execute_test/..: Permission denied 
ls: cannot access remove_execute/remove_execute_test/test_file.txt: Permission denied 
ls: cannot access remove_execute/remove_execute_test/.: Permission         denied 
total 0 
d????????? ? ? ? ?            ? . 
d????????? ? ? ? ?            ? ..
-????????? ? ? ? ?            ? test_file.txt

Unless we have root permissions.

$ sudo ls -la remove_execute/remove_execute_test/
total 8
drw-rw-r-- 2 zerodf zerodf 4096 Nov 21 10:51 .
drwxrwxr-x 3 zerodf zerodf 4096 Nov 21 10:51 ..
-rw-rw-r-- 1 zerodf zerodf    0 Nov 21 10:51 test_file.txt

Problem

When I write `ls -la` o the command line, I get this output: ``` ls -la /var/log/nginx d????????? ? ? ? ? ? . d????????? ? ? ? ? ? .. -????????? ? ? ? ? ? access.log ``` for all files in this folder. When I do it for another folder: ``` ls -la /var/log/nginx_back/ drwxr-xr-x 2 root root 4096 Апр 25 11:06 . drwxrwxr-x 15 root ssh 4096 Май 1 00:29 .. -rw-r--r-- 1 root root 220793880 Апр 25 11:04 access.log-20170401.gz ``` Everything is ok. Permissions on the directory above: ``` drw-r--r-- 2 nginx adm 69632 Май 1 00:29 nginx drwxr-xr-x 2 root root 4096 Апр 25 11:06 nginx_back ``` I have these question marks only when I'm not root. I've added my user to the group `nginx`, added all permissions, created another user, but the system doesn't want to show the file's attributes for non-superusers in the directory `/var/log/nginx`. Why is that?

Original source