[patch] enhance quoting for command string

[Martin Hunt]

On Thu, 2007-08-16 at 11:48 -0400, Frank Ch. Eigler wrote:

I have committed the patch.

> Let's put it this way.  It is important to pass this data verbatim (or
> at worst, reject questionable inputs).  How about a testsuite addition
> that confirms this from end to end?

Checked in. See systemtap.base/cmd_parse.exp.

> I would be happier if there were stress tests, and if there were fewer
> calls to system().  I'm happy to see that staprun already uses execl
> to run the commands passed from the tapset system() function.

I guess we are not talking about the same thing?  I thought when you
objected to using system() instead of exec() you meant running the
commands directly instead of in a shell, like system() does. Commands
run from the tapset system function are handled in the same way as
commands sent with "-c".  Both use 

Here's one
if (execl("/bin/sh", "sh", "-c", target_cmd, NULL) < 0)
and the other
if (execl("/bin/sh", "sh", "-c", cmd, NULL) < 0)

Internally this is exactly what system() does.  However we could never
use system() because system() waits for the process to complete before
returning.  

Martin