Gregory Nutt a64869aa67 CONFIG_NFILE_DESCRIPTORS=0 can no longer be used to disable the file system. NuttX with no file system does not make sense.
Squashed commit of the following:

    configs/:  The few configurations that formerly set CONFIG_NFILE_DESCRIPTORS=0 should not default, rather they should set the number of descriptors to 3.
    fs/:  Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0
    tools/:  Tools updates for changes to usage of CONFIG_NFILE_DESCRIPTORS.
    syscall/:  Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0
    libs/:  Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0
    include/:  Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0
    drivers/:  Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0
    Documentation/:  Remove all references to CONFIG_NFILE_DESCRIPTORS == 0
    binfmt/:  Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0
    arch/:  Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0
    net/:  Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0
    sched/:  Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0
    sched/Kconfig:  CONFIG_NFILE_DESCRIPTORS may no longer to set to a value less than 3
    configs/:  Remove all settings for CONFIG_NFILE_DESCRIPTORS < 3
2019-02-11 12:09:26 -06:00
..

fs/procfs README
================

  This is a tiny procfs file system that allows read-only access to a few
  attributes of a task or thread.  This tiny procfs fs file system can be
  built into the system by enabling:

    CONFIG_FS_PROCFS=y

  It can then be mounted from the NSH command like like:

    nsh> mount -t procfs /proc

Example
=======

  NuttShell (NSH) NuttX-6.31
  nsh> mount -t procfs /proc

  nsh> ls /proc
  /proc:
   0/
   1/

  nsh> ls /proc/1
  /proc/1:
   status
   cmdline

  nsh> cat /proc/1/status
  Name:       init
  Type:       Task
  State:      Running
  Priority:   100
  Scheduler:  SCHED_FIFO
  SigMask:    00000000

  nsh> cat /proc/1/cmdline
  init

  nsh> sleep 100 &
  sleep [2:100]
  nsh> ls /proc
  ls /proc
  /proc:
   0/
   1/
   2/

  nsh> cat /proc/2/cmdline
  <pthread> 0x527420