PROCFS(5)                 FreeBSD File Formats Manual                PROCFS(5)

NAME
     procfs - process file system

SYNOPSIS
     proc            /proc   procfs  rw 0 0

DESCRIPTION
     This functionality is deprecated.  Users are advised to use
     libprocstat(3) and kvm(3) instead.

     The process file system, or procfs, implements a view of the system
     process table inside the file system.  It is normally mounted on /proc.

     The procfs provides a two-level view of process space, unlike the
     previous FreeBSD 1.1 procfs implementation.  At the highest level,
     processes themselves are named, according to their process ids in
     decimal, with no leading zeros.  There is also a special node called
     curproc which always refers to the process making the lookup request.

     Each node is a directory which contains the following entries:

     dbregs  The debug registers as defined by struct dbregs in
             <machine/reg.h>.  dbregs is currently only implemented on the
             i386 architecture.

     etype   The type of the executable referenced by the file entry.

     file    A symbolic link to the file from which the process text was read.
             This can be used to gain access to the process' symbol table, or
             to start another copy of the process.  If the file cannot be
             found, the link target is `unknown'.

     fpregs  The floating point registers as defined by struct fpregs in
             <machine/reg.h>.  fpregs is only implemented on machines which
             have distinct general purpose and floating point register sets.

     map     A map of the process' virtual memory.

     mem     The complete virtual memory image of the process.  Only those
             address which exist in the process can be accessed.  Reads and
             writes to this file modify the process.  Writes to the text
             segment remain private to the process.

     note    Used for sending signals to the process.  Not implemented.

     notepg  Used for sending signal to the process group.  Not implemented.

     osrel   Allows read and write of the kernel osrel value assigned to the
             process.  It affects the compatibility shims that are turned on
             and off depending on the value.  Initial process value is read
             from the ABI note tag in the executed ELF image, and is zero if
             the tag not supported by binary format or was not found.

     regs    Allows read and write access to the process' register set.  This
             file contains a binary data structure struct regs defined in
             <machine/reg.h>.  regs can only be written when the process is
             stopped.

     rlimit  This is a read-only file containing the process current and
             maximum limits.  Each line is of the format rlimit current max,
             with -1 indicating infinity.

     status  The process status.  This file is read-only and returns a single
             line containing multiple space-separated fields as follows:

             •   command name
             •   process id
             •   parent process id
             •   process group id
             •   session id
             •   device name of the controlling terminal, or a minus sign
                 ("-") if there is no controlling terminal.
             •   a list of process flags: ctty if there is a controlling
                 terminal, sldr if the process is a session leader, noflags if
                 neither of the other two flags are set.
             •   the process start time in seconds and microseconds, comma
                 separated.
             •   the user time in seconds and microseconds, comma separated.
             •   the system time in seconds and microseconds, comma separated.
             •   the wait channel message
             •   the process credentials consisting of the effective user id
                 and the list of groups (whose first member is the effective
                 group id) all comma separated.
             •   the hostname of the jail in which the process runs, or `-' to
                 indicate that the process is not running within a jail.

     Each node is owned by the process's user, and belongs to that user's
     primary group.

FILES
     /proc                  normal mount point for the procfs.
     /proc/pid              directory containing process information for
                            process pid.
     /proc/curproc          directory containing process information for the
                            current process
     /proc/curproc/cmdline  the process executable name
     /proc/curproc/etype    executable type
     /proc/curproc/file     executable image
     /proc/curproc/fpregs   the process floating point register set
     /proc/curproc/map      virtual memory map of the process
     /proc/curproc/mem      the complete virtual address space of the process
     /proc/curproc/note     used for signaling the process
     /proc/curproc/notepg   used for signaling the process group
     /proc/curproc/osrel    the process osrel value
     /proc/curproc/regs     the process register set
     /proc/curproc/rlimit   the process current and maximum rlimit
     /proc/curproc/status   the process' current status

EXAMPLES
     To mount a procfs file system on /proc:

           mount -t procfs proc /proc

SEE ALSO
     procstat(1), mount(2), sigaction(2), unmount(2), pseudofs(9)

AUTHORS
     This manual page written by Garrett Wollman, based on the description
     provided by Jan-Simon Pendry, and revamped later by Mike Pritchard.

FreeBSD 13.1-RELEASE-p6        October 17, 2021        FreeBSD 13.1-RELEASE-p6