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)