# proc_self - process information - man(5) - [phpMan]

[_proc_pid_(5)](https://www.chedong.com/phpMan.php/man/procpid/5/markdown)                              File Formats Manual                             [_proc_pid_(5)](https://www.chedong.com/phpMan.php/man/procpid/5/markdown)

## NAME
       /proc/pid/, /proc/self/ - process information

## DESCRIPTION
       _/proc/_pid_/_
              There  is a numerical subdirectory for each running process; the subdirectory is named
              by the process ID.  Each _/proc/_pid subdirectory contains the pseudo-files and directo‐
              ries described below.

              The files inside each _/proc/_pid directory are normally owned by the effective user and
              effective group ID of the process.  However, as a security measure, the  ownership  is
              made _root:root_ if the process's "dumpable" attribute is set to a value other than 1.

              Before Linux 4.11, _root:root_ meant the "global" root user ID and group ID (i.e., UID 0
              and  GID  0  in the initial user namespace).  Since Linux 4.11, if the process is in a
              noninitial user namespace that has a valid mapping for user (group) ID  0  inside  the
              namespace,  then  the  user  (group) ownership of the files under _/proc/_pid is instead
              made the same as the root user (group) ID of the namespace.  This means that inside  a
              container, things work as expected for the container "root" user.

              The process's "dumpable" attribute may change for the following reasons:

              •  The attribute was explicitly set via the [**prctl**(2)](https://www.chedong.com/phpMan.php/man/prctl/2/markdown) **PR_SET_DUMPABLE **operation.

              •  The  attribute  was  reset to the value in the file _/proc/sys/fs/suid_dumpable_ (de‐
                 scribed below), for the reasons described in [**prctl**(2)](https://www.chedong.com/phpMan.php/man/prctl/2/markdown).

              Resetting the "dumpable" attribute to 1 reverts the ownership of the _/proc/_pid_/*_ files
              to the process's effective UID and GID.  Note, however, that if the effective  UID  or
              GID is subsequently modified, then the "dumpable" attribute may be reset, as described
              in  [**prctl**(2)](https://www.chedong.com/phpMan.php/man/prctl/2/markdown).   Therefore, it may be desirable to reset the "dumpable" attribute _after_
              making any desired changes to the process's effective UID or GID.

       _/proc/self/_
              This directory refers to the process accessing the _/proc_ filesystem, and is  identical
              to the _/proc_ directory named by the process ID of the same process.

## SEE ALSO
       [**proc**(5)](https://www.chedong.com/phpMan.php/man/proc/5/markdown)

Linux man-pages 6.7                          2023-08-15                                  [_proc_pid_(5)](https://www.chedong.com/phpMan.php/man/procpid/5/markdown)