proc_pid_map_files(5)         File Formats Manual        proc_pid_map_files(5)

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)

Linux man-pages 6.9.1             2024-05-02             proc_pid_map_files(5)