NAME    [Toc]    [Back]

     mount_procfs - mount the process file system

SYNOPSIS    [Toc]    [Back]

     mount_procfs [-o options] /proc mount_point

DESCRIPTION    [Toc]    [Back]

     The mount_procfs command attaches an instance of the process
namespace to
     the  global  filesystem  namespace.   The conventional mount
point is /proc.
     This command is normally executed by mount(8) at boot  time.

     The options are as follows:

     -o options
             Options  are  specified with a -o flag followed by a
comma separated
 string of options.  See the mount(8) man page for
possible options
 and their meanings.  The following procfs specific option
             is also available:

             linux   Add Linux compatibility links and  nodes  to
procfs.

     The  root  of  the  process filesystem contains an entry for
each active process.
  These processes are visible as a directory whose name
is the process's
  PID.   In addition, the special entry curproc references the current
 process.

     Each directory contains several files.

     cmdline
             Process command line parameters, separated by  NULs.

     ctl      A  write-only file which supports a variety of control operations.
             Control commands are written as strings to  the  ctl
file.  The
             control commands are:

             attach   Stops  the  target process and arranges for
the sending
                     process to become the debug control process.
             detach   Continues  execution  of the target process
and removes it
                     from control by  the  debug  process  (which
need not be the
                     sending process).
             run     Continues running the target process until a
signal is
                     delivered, a breakpoint is hit, or the  target process exits.

             step     Single  steps  the  target process, with no
signal delivery.
             wait    Waits for the target process to  come  to  a
steady state
                     ready  for  debugging.   The  target process
must be in this
                     state before any of the other  commands  are
allowed.

             The  string  can also be the name of a signal, lower
case and without
 the SIG prefix, in which case that signal is delivered to the
             process (see sigaction(2)).

     file    A reference to the vnode from which the process text
was read.
             This can be used to gain  access  to  the  process's
symbol table, or
             to start another copy of the process.

     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.

     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    Not implemented.

     notepg  Not implemented.

     regs    Allows read and write access to the process's 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.

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

             +o   Command name.
             +o   Process ID.
             +o   Parent process ID.
             +o   Process group ID.
             +o   Session ID.
             +o   major,minor  of  the  controlling  terminal,  or
-1,-1 if there is
                 no controlling terminal.
             +o    List  of process flags: ctty if there is a controlling terminal,
 sldr if the process is a session leader, or
noflags if
                 neither of the other two flags are set.
             +o    Process start time in seconds and microseconds,
comma separated.

             +o   User time in  seconds  and  microseconds,  comma
separated.
             +o    System  time in seconds and microseconds, comma
separated.
             +o   Wait channel message.
             +o   Process credentials consisting of the  effective
user ID and
                 the  list  of  groups (whose first member is the
effective group
                 ID), all comma separated.

     In a normal  debugging  environment,  where  the  target  is
fork/exec'd by the
     debugger, the debugger should fork and the child should stop
itself (with
     a self-inflicted SIGSTOP for example).   The  parent  should
issue a wait
     and  then  an  attach  command via the appropriate ctl file.
The child process
 will receive a SIGTRAP immediately after  the  call  to
exec (see
     execve(2)).

     Statistics reported by df(1) on a procfs filesystem will indicate virtual
     memory used/available instead of `disk space', and the  number of process
     slots used/allocated instead of `inodes'.  The block size of
the filesystem
 is the system page size.

FILES    [Toc]    [Back]

     /proc/#
     /proc/curproc
     /proc/curproc/cmdline
     /proc/curproc/ctl
     /proc/curproc/file
     /proc/curproc/fpregs
     /proc/curproc/mem
     /proc/curproc/note
     /proc/curproc/notepg
     /proc/curproc/regs
     /proc/curproc/status

SEE ALSO    [Toc]    [Back]

     mount(2), sigaction(2), fstab(5), mount(8), umount(8)

HISTORY    [Toc]    [Back]

     The mount_procfs utility first appeared in 4.4BSD.

CAVEATS    [Toc]    [Back]

     This filesystem may not be NFS-exported since  most  of  the
functionality
     of procfs requires that state be maintained.

OpenBSD      3.6                          March      27,     1994