NAME

       /proc/pid/map_files/ - memory-mapped files

DESCRIPTION

       /proc/pid/map_files/ (since Linux 3.3)
              This  subdirectory  contains  entries corresponding to memory-mapped files (see mmap(2)).  Entries
              are named by memory region start and end address pair (expressed as hexadecimal numbers), and  are
              symbolic  links  to  the mapped files themselves.  Here is an example, with the output wrapped and
              reformatted to fit on an 80-column display:

                  # ls -l /proc/self/map_files/
                  lr--------. 1 root root 64 Apr 16 21:31
                              3252e00000-3252e20000 -> /usr/lib64/ld-2.15.so
                  ...

              Although these entries are present for memory regions that were mapped with the MAP_FILE flag, the
              way  anonymous shared memory (regions created with the MAP_ANON | MAP_SHARED flags) is implemented
              in Linux means that such regions also appear on this directory.  Here  is  an  example  where  the
              target file is the deleted /dev/zero one:

                  lrw-------. 1 root root 64 Apr 16 21:33
                              7fc075d2f000-7fc075e6f000 -> /dev/zero (deleted)

              Permission to access this file is governed by a ptrace access mode PTRACE_MODE_READ_FSCREDS check;
              see ptrace(2).

              Until  Linux  4.3,  this  directory  appeared  only  if   the   CONFIG_CHECKPOINT_RESTORE   kernel
              configuration option was enabled.

              Capabilities  are  required  to  read the contents of the symbolic links in this directory: before
              Linux 5.9, the reading process requires CAP_SYS_ADMIN in the initial user namespace;  since  Linux
              5.9,  the  reading process must have either CAP_SYS_ADMIN or CAP_CHECKPOINT_RESTORE in the initial
              (i.e. root) user namespace.

SEE ALSO

       proc(5)