[jira] [Commented] (CASSANDRA-13211) cassandra shell script uses bad approach to write "Unable to find java" error to stderr, causing real issue to be masked by a permission error if user has changed user since logging in

["Nate McCall (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-13211?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15863162#comment-15863162 ] 

Nate McCall commented on CASSANDRA-13211:
-----------------------------------------

I have a vague recollection of dealing with pseudoterminal ownership issues when doing {{su}}, so I could see this. [~brandon.williams] probably has a lot better bash foo than me. 

> cassandra shell script uses bad approach to write "Unable to find java" error to stderr, causing real issue to be masked by a permission error if user has changed user since logging in
> ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: CASSANDRA-13211
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-13211
>             Project: Cassandra
>          Issue Type: Bug
>            Reporter: Max Bowsher
>
> The cassandra startup shell script contains this line:
>     echo Unable to find java executable. Check JAVA_HOME and PATH environment variables. > /dev/stderr
> The problem here is the construct "> /dev/stderr". If the user invoking Cassandra has changed user (for example, by SSHing in as a personal user, and then sudo-ing to an application user responsible for executing the Cassandra daemon), then the attempt to open /dev/stderr will fail, because it will point to a PTY node under /dev/pts/ owned by the original user.
> Ultimately this leads to the real problem being masked by the confusing error message "bash: /dev/stderr: Permission denied".
> The correct technique is to replace "> /dev/stderr" with ">&2" which will write to the already open stderr file descriptor, instead of resolving the chain of symlinks starting at /dev/stderr, and attempting to reopen the target by name.



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