NAME
mount_procfs
—
mount the process file
system
SYNOPSIS
mount_procfs |
[-o options]
/proc mount_point |
DESCRIPTION
Themount_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.
- maps
- A map of the process' virtual memory in a form like the proc filesystem as implemented in Linux. Note that the paths corresponding to file backed mappings will not be present unless the kernel was built with the NAMECACHE_ENTER_REVERSE option.
- 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.
FILES
- /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
SEE ALSO
HISTORY
The mount_procfs
utility first appeared in
4.4BSD.
BUGS
This filesystem may not be NFS-exported since most of the
functionality of procfs
requires that state be
maintained.