From domU read the xenstore (ec2, linode etc)

In case you wonder what is the dom0 running for your instance/vps this will give you information from xenstore. Taken from a FreeBSD receipe and adapted to linux.

Building & installation
-----------------------

Prerequisites: make, XENHVM or XEN kernel (GENERIC will not work) - all this is already there if you run as pv.

1. wget http://bits.xensource.com/oss-xen/release/4.1.1/xen-4.1.1.tar.gz

2. tar xvfz xen-4.1.1.tar.gz

3. cd xen-4.1.1/tools

4. make -C include

5. cd misc

6. make xen-detect

7. install xen-detect /usr/local/bin

8. cd ../xenstore

9. Build client library and programs:
  make clients

10. Install client library and programs:
  install libxenstore.so.3.0 /usr/local/lib
  install xenstore xenstore-control /usr/local/bin
  cd /usr/local/bin
  ln xenstore xenstore-chmod
  ln xenstore xenstore-exists
  ln xenstore xenstore-list
  ln xenstore xenstore-ls
  ln xenstore xenstore-read
  ln xenstore xenstore-rm
  ln xenstore xenstore-write

(in case that your ld loader doesn't look into /usr/local/lib do this
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib)


Usage
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1. Set required environment variable:
  export XENSTORED_PATH=/dev/xen/xenstore -- FreeBSD
  export XENSTORED_PATH=/proc/xen/xenbus -- Linux

2. Now you can do things such as:
  xen-detect
  xenstore-ls device
  xenstore-ls -f /local/domain/0/backend/vif/11/0
  xenstore-read name