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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 hexadeci‐
              mal numbers), and are symbolic links to the mapped files themselves.  Here is an exam‐
              ple, 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 direc‐
              tory: 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 6.7                          2023-08-15                        proc_pid_map_files(5)