VError: Write to CapeMgr slots failed: EACCES: permission denied, open '/sys/devices/platform/bone_capemgr/slots'

[troywweber7]

I've freshly installed the official BeagleBone Green Wireless image on my BBGW, so I'm running Debian 8.6.

I've fully updated the software on the board multiple times to make sure I am up to date with sudo apt-get update && sudo apt-get -y upgrade.

Also, I created a new user deploy and have sudo permissions. As deploy I've installed Node 7.10 using nvm.

In a test folder, I initialized a simple package.json and npm i -S octalbonescript. It installs fine, so I go into the node interpreter and try to import octalbonescript and havoc ensues:

$ cat package.json 
{
  "name": "test-octalbonescript",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "octalbonescript": "^1.3.1"
  }
}
$ clear

$ node
> obs = require('octalbonescript')
VError: Write to CapeMgr slots failed: EACCES: permission denied, open '/sys/devices/platform/bone_capemgr/slots'
  at onWriteSlots (/home/deploy/code/test-octalbonescript/node_modules/octalbonescript/lib/bone.js:289:23)
  at onReadSlots (/home/deploy/code/test-octalbonescript/node_modules/octalbonescript/lib/bone.js:280:17)
  at readSlots (/home/deploy/code/test-octalbonescript/node_modules/octalbonescript/lib/bone.js:260:13)
  at Object.load_dt_sync (/home/deploy/code/test-octalbonescript/node_modules/octalbonescript/lib/bone.js:251:9)
  at Object.load_universal_cape (/home/deploy/code/test-octalbonescript/node_modules/octalbonescript/lib/bone.js:144:24)
  at Object.<anonymous> (/home/deploy/code/test-octalbonescript/node_modules/octalbonescript/index.js:37:18)
  at Module._compile (module.js:571:32)
  at Object.Module._extensions..js (module.js:580:10)
  at Module.load (module.js:488:32)
  at tryModuleLoad (module.js:447:12)
  at Function.Module._load (module.js:439:3)
  at Module.require (module.js:498:17)
  at require (internal/module.js:20:19)
  at repl:1:7
  at ContextifyScript.Script.runInThisContext (vm.js:23:33)
  at REPLServer.defaultEval (repl.js:339:29)
  at bound (domain.js:280:14)
  at REPLServer.runBound [as eval] (domain.js:293:12)
  at REPLServer.onLine (repl.js:536:10)
  at emitOne (events.js:101:20)
  at REPLServer.emit (events.js:191:7)
  at REPLServer.Interface._onLine (readline.js:241:10)
  at REPLServer.Interface._line (readline.js:590:8)
  at REPLServer.Interface._ttyWrite (readline.js:869:14)
  at REPLServer.self._ttyWrite (repl.js:609:7)
  at ReadStream.onkeypress (readline.js:120:10)
  at emitTwo (events.js:106:13)
  at ReadStream.emit (events.js:194:7)
  at emitKeys (internal/readline.js:402:14)
  at emitKeys.next (<anonymous>:null:null)
  at ReadStream.onData (readline.js:980:36)
  at emitOne (events.js:96:13)
  at ReadStream.emit (events.js:191:7)
  at readableAddChunk (_stream_readable.js:178:18)
  at ReadStream.Readable.push (_stream_readable.js:136:10)
  at TTY.onread (net.js:561:20)

> 
(To exit, press ^C again or type .exit)
> 

[troywweber7]

So if I set the group of the file giving the EACCESS error to gpio, and have myself added to gpio group, and change the mod with chmod g+w then obs loads within Node 7.10 just fine. I can do the same process for the USR0 led. But I need to do this to every pin that might be accessed from octalbonescript in Node 7.10. Can anyone point me to documentation on how to achieve this so it is persistent across restarts?

[albham]

I solved this issue defining the file /etc/udev/rules.d/75-bone_capemgr-noroot.rules, based in 80-gpio-noroot.rules, with content:

# Change group to gpio
SUBSYSTEM=="platform", PROGRAM="/bin/sh -c '/bin/chown -R root:gpio /sys/devices/platform/bone_capemgr'"
# Change user permissions to ensure user and group have read/write permissions
SUBSYSTEM=="platform", PROGRAM="/bin/sh -c '/bin/chmod -R ug+rw /sys/devices/platform/bone_capemgr'"

[adityapatadia]

This library is abandoned. Please check notice in README for further information.