proc

README

This document tracks what is implemented in procfs. Refer to Documentation/filesystems/proc.txt in the Linux project for information about procfs generally.

NOTE: This document is not guaranteed to be up to date. If you find an inconsistency, please file a bug.

[TOC]

Kernel data

The following files are implemented:

File /proc/	Content
cpuinfo	Info about the CPU
filesystem	Supported filesystems
loadavg	Load average of last 1, 5 & 15 minutes
meminfo	Overall memory info
stat	Overall kernel statistics
sys	Change parameters within the kernel
uptime	Wall clock since boot, combined idle time of all
: : cpus :
version	Kernel version

cpuinfo

$ cat /proc/cpuinfo
processor   : 0
vendor_id   : GenuineIntel
cpu family  : 6
model       : 45
model name  : unknown
stepping    : unknown
cpu MHz     : 1234.588
fpu     : yes
fpu_exception   : yes
cpuid level : 13
wp      : yes
flags       : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx xsaveopt
bogomips    : 1234.59
clflush size    : 64
cache_alignment : 64
address sizes   : 46 bits physical, 48 bits virtual
power management:

...

Notable divergences:

Field name	Notes
model name	Always unknown
stepping	Always unknown
fpu	Always yes
fpu_exception	Always yes
wp	Always yes
bogomips	Bogus value (matches cpu MHz)
clflush size	Always 64
cache_alignment	Always 64
address sizes	Always 46 bits physical, 48 bits virtual
power management	Always blank

Otherwise fields are derived from the SentryCPUIDSpec proto config.

filesystem

$ cat /proc/filesystem
nodev   9p
nodev   devtmpfs
nodev   proc
nodev   ramdiskfs
nodev   sysfs
nodev   tmpfs

Notable divergences:

Filesystem	Notes
ramdiskfs	No Linux equivalent, see the SentryRamdiskFS proto config

loadavg

$ cat /proc/loadavg
0.00 0.00 0.00 0/0 0

Column	Notes
CPU.IO utilization in last 1 minute	Always zero
CPU.IO utilization in last 5 minutes	Always zero
CPU.IO utilization in last 10 minutes	Always zero
Num currently running processes	Always zero
Total num processes	Always zero

TODO: Populate the columns with accurate statistics.

meminfo

$ cat /proc/meminfo
MemTotal:        2097152 kB
MemFree:         2083540 kB
MemAvailable:    2083540 kB
Buffers:               0 kB
Cached:             4428 kB
SwapCache:             0 kB
Active:            10812 kB
Inactive:           2216 kB
Active(anon):       8600 kB
Inactive(anon):        0 kB
Active(file):       2212 kB
Inactive(file):     2216 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:             0 kB
SwapFree:              0 kB
Dirty:                 0 kB
Writeback:             0 kB
AnonPages:          8600 kB
Mapped:             4428 kB
Shmem:                 0 kB

Notable divergences:

Field name	Notes
Buffers	Always zero, no block devices
SwapCache	Always zero, no swap
Inactive(anon)	Always zero, see SwapCache
Unevictable	Always zero TODO
Mlocked	Always zero TODO
SwapTotal	Always zero, no swap
SwapFree	Always zero, no swap
Dirty	Always zero TODO
Writeback	Always zero TODO
MemAvailable	Uses the same value as MemFree since there is no swap.
Slab	Missing
SReclaimable	Missing
SUnreclaim	Missing
KernelStack	Missing
PageTables	Missing
NFS_Unstable	Missing
Bounce	Missing
WritebackTmp	Missing
CommitLimit	Missing
Committed_AS	Missing
VmallocTotal	Missing
VmallocUsed	Missing
VmallocChunk	Missing
HardwareCorrupted	Missing
AnonHugePages	Missing
ShmemHugePages	Missing
ShmemPmdMapped	Missing
HugePages_Total	Missing
HugePages_Free	Missing
HugePages_Rsvd	Missing
HugePages_Surp	Missing
Hugepagesize	Missing
DirectMap4k	Missing
DirectMap2M	Missing
DirectMap1G	Missing

See Memory Accounting for general caveats.

stat

$ cat /proc/stat
cpu  0 0 0 0 0 0 0 0 0 0
cpu0 0 0 0 0 0 0 0 0 0 0
cpu1 0 0 0 0 0 0 0 0 0 0
cpu2 0 0 0 0 0 0 0 0 0 0
cpu3 0 0 0 0 0 0 0 0 0 0
cpu4 0 0 0 0 0 0 0 0 0 0
cpu5 0 0 0 0 0 0 0 0 0 0
cpu6 0 0 0 0 0 0 0 0 0 0
cpu7 0 0 0 0 0 0 0 0 0 0
intr 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
ctxt 0
btime 1504040968
processes 0
procs_running 0
procs_blokkcked 0
softirq 0 0 0 0 0 0 0 0 0 0 0

All fields except for btime are always zero. TODO: Populate with accurate fields.

sys

$ ls /proc/sys
kernel vm

Directory	Notes
abi	Missing
debug	Missing
dev	Missing
fs	Missing
kernel	Contains hostname (only)
net	Missing
user	Missing
vm	Contains mmap_min_addr (only)

uptime

$ cat /proc/uptime
3204.62 0.00

Column	Notes
Total num seconds system running	Time since procfs was mounted
Number of seconds idle	Always zero

version

$ cat /proc/version
Linux version 3.11.10 #1 SMP Fri Nov 29 10:47:50 PST 2013

Process-specific data

The following files are implemented:

File /proc/PID	Content
auxv	Copy of auxiliary vector for the process
cmdline	Command line arguments
comm	Command name associated with the process
exe	Symlink to the process's executable
fd	Directory containing links to open file descriptors
fdinfo	Information associated with open file descriptors
gid_map	Mappings for group IDs inside the user namespace
io	IO statistics
maps	Memory mappings (anon, executables, library files)
ns	Directory containing info about supported namespaces
stat	Process statistics
status	Process status in human readable format
task	Directory containing info about running threads
uid_map	Mappings for user IDs inside the user namespace

auxv

TODO

cmdline

TODO

comm

TODO

exe

TODO

fd

TODO

fdinfo

TODO

gid_map

TODO

io

Only has data for rchar, wchar, syscr, and syscw.

TODO: add more detail.

maps

TODO

ns

TODO

stat

Only has data for pid, comm, state, ppid, utime, stime, cutime, cstime, num_threads, and exit_signal.

TODO: add more detail.

status

Statically created, most of the fields have no data.

TODO: add more detail.

task

TODO

uid_map

TODO

Documentation

Overview

Package proc implements a partial in-memory file system for profs.

Index

• Constants
• func New(ctx context.Context, msrc *fs.MountSource) (*fs.Inode, error)

Constants

const FilesystemName = "proc"

FilesystemName is the name underwhich the filesystem is registered. Name matches fs/proc/root.c:proc_fs_type.name.

Functions

func New

func New(ctx context.Context, msrc *fs.MountSource) (*fs.Inode, error)

New returns the root node of a partial simple procfs.