mount_procfs
—
mount the process file system
mount_procfs |
[-o options]
/proc mount_point |
The mount_procfs
command attaches an
instance of the process namespace to the global filesystem namespace. The
conventional mount point is /proc. The directory
specified by mount_point is converted to an absolute
path before use. This command is normally executed by
mount(8) at boot time.
The options are as follows:
-o
nolinux
- Do not support nodes which are not part of the original procfs
implementation but have been added for compatibility with the Linux procfs
namespace. See FILES for more
information.
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' pid. In addition, the special entries
curproc and self reference
the current process. The self symlink appears for
compatibility with the Linux procfs implementation.
Each directory contains several files.
- cmdline
- This file is readonly and returns null-terminated strings corresponding to
the process' command line arguments. For a system or zombie process, this
file contains only a string with the name of the process.
- cwd
- A symbolic link that points to the current working directory of the
process. If the target process's current working directory is not
available or is not at or below the current process's root directory, this
link will point to “/”.
- fd/#
- File descriptors which can be accessed through the file system. See
fd(4) for more information.
- file
- A reference to the vnode 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.
- map
- A map of the process' virtual memory. This file comprises lines describing
the memory regions of the process, where each line contains the following
fields:
- start-address
- The starting address of the region (inclusive).
- end-address
- The ending address of the region (exclusive).
- protection
- The access permissions for the region, represented as a
three-character string using the characters ‘r’,
‘w’ and ‘x’ to denote read, write, and
execute permission respectively. The lack of a permission is
represented by a ‘-’.
- max-protection
- The maximum access permissions for the region represented as a three
character string using the characters ‘r’,
‘w’ and ‘x’ to denote read, write, and
execute permission respectively. The lack of a permission is
represented by a ‘-’.
- copy-on-write
- Whether the region is copy-on-write. One of:
- COW
- A region that is copy-on-write.
- NCOW
- A region that is not copy-on-write.
- needs-copy
- Whether the region needs a copy. One of:
- NC
- The region needs a copy.
- NNC
- The region does not need a copy.
- inheritance
- The inheritance code for the region, as set by
minherit(2).
- wired-count
- The wired count for the region. The region can be paged out if its
wired count is zero.
- advice
- The advice value set by a prior call to
madvise(2) for the
region.
- maps
- A map of the process' virtual memory in a form like the proc filesystem as
implemented in Linux. This file comprises lines describing the memory
regions of the process, where each line contains the following fields:
- start-address
- The starting address of the region (inclusive).
- end-address
- The ending address of the region (exclusive).
- protection
- The access permissions for the region, represented as a
three-character string using the characters ‘r’,
‘w’ and ‘x’ to denote read, write, and
execute permission respectively. The lack of a permission is
represented by a ‘-’.
- copy-on-write
- Whether the region is copy-on-write. One of:
- ‘p’
- The region is copy-on-write.
- ‘s’
- The region is shared.
- offset
- The offset into the file being mapped by the region.
- device-id
- The major and minor number of the device containing the file being
mapped by the region.
- fileid
- The inode for the file associated with the region.
- path
- The pathname to the file associated with the region.
- mem
- The complete virtual memory image of the process. Only those addresses
which exist in the process can be accessed. Writes to this file modify the
process. Writes to the text segment normally remain private to the
process, since the text segment is mapped with MAP_PRIVATE; however, this
is not guaranteed.
- note
- Not implemented.
- notepg
- Not implemented.
- 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.
- 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.
- root
- A symbolic link that points to the root directory of the process. If the
target process's root directory is not available or is not at or below the
current process's root directory, this link will point to
“/”.
- status
- The process status. This file is readonly and returns a single line
containing multiple space-separated fields as follows:
- command name
- process id
- parent process id
- process group id
- session id
- major,minor of the controlling terminal, or
-1,-1
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.
- /proc/#
-
- /proc/#/cmdline
-
- /proc/#/cwd
-
- /proc/#/exe
-
- /proc/#/file
-
- /proc/#/fpregs
-
- /proc/#/map
-
- /proc/#/maps
-
- /proc/#/mem
-
- /proc/#/note
-
- /proc/#/notepg
-
- /proc/#/regs
-
- /proc/#/root
-
- /proc/#/status
-
- /proc/curproc
-
- /proc/self
-
If the linux
mount option is used, the
following files are also available:
- /proc/#/stat
-
- /proc/cpuinfo
-
- /proc/devices
-
- /proc/meminfo
-
- /proc/mounts
-
- /proc/uptime
-
The mount_procfs
utility first appeared in
4.4BSD.
This filesystem may not be NFS-exported since most of the
functionality of procfs
requires that state be
maintained.