Running arbitrary commands in AWS::CloudFormation::Init is broken

[Zane Bitter]

In heat-cfntools 1.4.0, the fix for bug 1312246 breaks the "commands" section in of AWS::CloudFormation::Init. These commands should be arbitrary shell commands, as seen in the AWS docs at http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-init.html where the examples are e.g. redirecting output to a file. The new implementation simply splits that commands on whitespace and passes the result to execvp(), rather than allowing the shell to interpret.

[Zane Bitter (zaneb)]

Note that when the command is supplied by the user as a list rather than a string, we *should* to pass it directly to execvp(). Currently we are doing some (bad) escaping, converting it to a string, then splitting it on whitespace and passing it to execvp(). Previously we were doing the bad escaping and passing it to the shell, which was not much better.

[Anant Patil (ananta)]

This should be fixed now after the offending patch was reverted.

In another fix to bug 1312246, I have taken care of this.