278 lines
6.7 KiB
Groff
278 lines
6.7 KiB
Groff
.\" $FreeBSD$
|
|
.\" Written by Garrett Wollman
|
|
.\" This file is in the public domain.
|
|
.\"
|
|
.Dd September 22, 2009
|
|
.Dt PROCFS 5
|
|
.Os
|
|
.Sh NAME
|
|
.Nm procfs
|
|
.Nd process file system
|
|
.Sh SYNOPSIS
|
|
.Bd -literal
|
|
proc /proc procfs rw 0 0
|
|
.Ed
|
|
.Sh DESCRIPTION
|
|
The process file system, or
|
|
.Nm ,
|
|
implements a view of the system process table inside the file system.
|
|
It is normally mounted on
|
|
.Pa /proc ,
|
|
and is required for the complete operation of programs such as
|
|
.Xr ps 1
|
|
and
|
|
.Xr w 1 .
|
|
.Pp
|
|
The
|
|
.Nm
|
|
provides a two-level view of process space, unlike the previous
|
|
.Fx 1.1
|
|
.Nm
|
|
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
|
|
.Pa curproc
|
|
which always refers to the process making the lookup request.
|
|
.Pp
|
|
Each node is a directory which contains the following entries:
|
|
.Pp
|
|
Each directory contains several files:
|
|
.Bl -tag -width status
|
|
.It Pa ctl
|
|
a write-only file which supports a variety
|
|
of control operations.
|
|
Control commands are written as strings to the
|
|
.Pa ctl
|
|
file.
|
|
The control commands are:
|
|
.Bl -tag -width detach -compact
|
|
.It attach
|
|
stops the target process and arranges for the sending
|
|
process to become the debug control process.
|
|
.It detach
|
|
continue execution of the target process and
|
|
remove it from control by the debug process (which
|
|
need not be the sending process).
|
|
.It run
|
|
continue running the target process until
|
|
a signal is delivered, a breakpoint is hit, or the
|
|
target process exits.
|
|
.It step
|
|
single step the target process, with no signal delivery.
|
|
.It wait
|
|
wait 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.
|
|
.El
|
|
.Pp
|
|
The string can also be the name of a signal, lower case
|
|
and without the
|
|
.Dv SIG
|
|
prefix,
|
|
in which case that signal is delivered to the process
|
|
(see
|
|
.Xr sigaction 2 ) .
|
|
.Pp
|
|
The
|
|
.Xr procctl 8
|
|
utility can be used to clear tracepoints in a stuck process.
|
|
.It Pa dbregs
|
|
The debug registers as defined by
|
|
.Dv "struct dbregs"
|
|
in
|
|
.In machine/reg.h .
|
|
.Pa dbregs
|
|
is currently only implemented on the i386 architecture.
|
|
.It Pa etype
|
|
The type of the executable referenced by the
|
|
.Pa file
|
|
entry.
|
|
.It Pa 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
|
|
.Ql unknown .
|
|
.It Pa fpregs
|
|
The floating point registers as defined by
|
|
.Dv "struct fpregs"
|
|
in
|
|
.In machine/reg.h .
|
|
.Pa fpregs
|
|
is only implemented on machines which have distinct general
|
|
purpose and floating point register sets.
|
|
.It Pa map
|
|
A map of the process' virtual memory.
|
|
.It Pa 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.
|
|
.It Pa note
|
|
Used for sending signals to the process.
|
|
Not implemented.
|
|
.It Pa notepg
|
|
Used for sending signal to the process group.
|
|
Not implemented.
|
|
.It Pa 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.
|
|
.It Pa regs
|
|
Allows read and write access to the process' register set.
|
|
This file contains a binary data structure
|
|
.Dv "struct regs"
|
|
defined in
|
|
.In machine/reg.h .
|
|
.Pa regs
|
|
can only be written when the process is stopped.
|
|
.It Pa rlimit
|
|
This is a read-only file containing the process current and maximum
|
|
limits.
|
|
Each line is of the format
|
|
.Ar rlimit current max ,
|
|
with -1
|
|
indicating infinity.
|
|
.It Pa status
|
|
The process status.
|
|
This file is read-only and returns a single line containing
|
|
multiple space-separated fields as follows:
|
|
.Pp
|
|
.Bl -bullet -compact
|
|
.It
|
|
command name
|
|
.It
|
|
process id
|
|
.It
|
|
parent process id
|
|
.It
|
|
process group id
|
|
.It
|
|
session id
|
|
.It
|
|
.Ar major , Ns Ar minor
|
|
of the controlling terminal, or
|
|
.Dv -1,-1
|
|
if there is no controlling terminal.
|
|
.It
|
|
a list of process flags:
|
|
.Dv ctty
|
|
if there is a controlling terminal,
|
|
.Dv sldr
|
|
if the process is a session leader,
|
|
.Dv noflags
|
|
if neither of the other two flags are set.
|
|
.It
|
|
the process start time in seconds and microseconds,
|
|
comma separated.
|
|
.It
|
|
the user time in seconds and microseconds,
|
|
comma separated.
|
|
.It
|
|
the system time in seconds and microseconds,
|
|
comma separated.
|
|
.It
|
|
the wait channel message
|
|
.It
|
|
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.
|
|
.It
|
|
the hostname of the jail in which the process runs, or
|
|
.Ql -
|
|
to indicate that the process is not running within a jail.
|
|
.El
|
|
.El
|
|
.Pp
|
|
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
|
|
.Dv SIGSTOP
|
|
for example).
|
|
The parent should issue a
|
|
.Dv wait
|
|
and then an
|
|
.Dv attach
|
|
command via the appropriate
|
|
.Pa ctl
|
|
file.
|
|
The child process will receive a
|
|
.Dv SIGTRAP
|
|
immediately after the call to exec (see
|
|
.Xr execve 2 ) .
|
|
.Pp
|
|
Each node is owned by the process's user, and belongs to that user's
|
|
primary group, except for the
|
|
.Pa mem
|
|
node, which belongs to the
|
|
.Li kmem
|
|
group.
|
|
.Sh FILES
|
|
.Bl -tag -width /proc/curproc/XXXXXXX -compact
|
|
.It Pa /proc
|
|
normal mount point for the
|
|
.Nm .
|
|
.It Pa /proc/pid
|
|
directory containing process information for process
|
|
.Pa pid .
|
|
.It Pa /proc/curproc
|
|
directory containing process information for the current process
|
|
.It Pa /proc/curproc/cmdline
|
|
the process executable name
|
|
.It Pa /proc/curproc/ctl
|
|
used to send control messages to the process
|
|
.It Pa /proc/curproc/etype
|
|
executable type
|
|
.It Pa /proc/curproc/file
|
|
executable image
|
|
.It Pa /proc/curproc/fpregs
|
|
the process floating point register set
|
|
.It Pa /proc/curproc/map
|
|
virtual memory map of the process
|
|
.It Pa /proc/curproc/mem
|
|
the complete virtual address space of the process
|
|
.It Pa /proc/curproc/note
|
|
used for signaling the process
|
|
.It Pa /proc/curproc/notepg
|
|
used for signaling the process group
|
|
.It Pa /proc/curproc/osrel
|
|
the process osrel value
|
|
.It Pa /proc/curproc/regs
|
|
the process register set
|
|
.It Pa /proc/curproc/rlimit
|
|
the process current and maximum rlimit
|
|
.It Pa /proc/curproc/status
|
|
the process' current status
|
|
.El
|
|
.Sh EXAMPLES
|
|
To mount a
|
|
.Nm
|
|
file system on
|
|
.Pa /proc :
|
|
.Pp
|
|
.Dl "mount -t procfs proc /proc"
|
|
.Sh SEE ALSO
|
|
.Xr procstat 1 ,
|
|
.Xr mount 2 ,
|
|
.Xr sigaction 2 ,
|
|
.Xr unmount 2 ,
|
|
.Xr procctl 8 ,
|
|
.Xr pseudofs 9
|
|
.Sh AUTHORS
|
|
.An -nosplit
|
|
This manual page written by
|
|
.An Garrett Wollman ,
|
|
based on the description
|
|
provided by
|
|
.An Jan-Simon Pendry ,
|
|
and revamped later by
|
|
.An Mike Pritchard .
|