Re: [PATCH v2 1/3] kernel-shark: Provide parsing for quotation marks in Record command line

["Yordan Karadzhov (VMware)" <y.karadz@gmail.com>]

On 20.09.19 г. 2:20 ч., Steven Rostedt wrote:
> On Wed, 18 Sep 2019 17:23:17 +0300
> "Yordan Karadzhov (VMware)" <y.karadz@gmail.com> wrote:
> 
>> +/**
>> + * Separate the command line arguments inside the string taking into account
>> + * possible shell quoting and new lines.
>> + */
>> +QStringList splitArguments(QString cmd)
>> +{
>> +	QString::SplitBehavior opt = QString::SkipEmptyParts;
>> +	int i, progress = 0, size;
>> +	QStringList argv;
>> +	QChar quote = 0;
>> +
>> +	/* Remove all new lines. */
>> +	cmd.replace("\\\n", " ");
>> +
>> +	size = cmd.count();
>> +	auto lamMid = [&] () {return cmd.mid(progress, i - progress);};
>> +	for (i = 0; i < size; ++i) {
>> +		if (cmd[i] == '\\') {
>> +			cmd.remove(i, 1);
>> +			size --;
>> +			continue;
>> +		}
>> +
>> +		if (cmd[i] == '\'' || cmd[i] == '"') {
>> +			if (quote.isNull()) {
>> +				argv << lamMid().split(" ", opt);
>> +				quote = cmd[i++];
>> +				progress = i;
>> +			} else if (quote == cmd[i]) {
>> +				argv << lamMid();
>> +				quote = 0;
>> +				progress = ++i;
>> +			}
>> +		}
>> +	}
>> +
>> +	argv << cmd.right(size - progress).split(" ", opt);
>> +
>> +	return argv;
>> +}
> 
> I still find the above hard to read, but so be it ;-)
> 
> Anyway, not quite yet. I just noticed that if I do:
> 
>    echo "this \" is \" a \"test"
> 
> The output has:
> 
> ("echo", "this \" is \" a \"test")
> 

Hi Steven,

This is a Qt printing artifact. The printout is trying to show clearly 
that this list contain only 2 strings. That is why it adds those 
backslashes. In the code of the example, try adding this:

                 if (ok) {
                         argList = KsUtils::splitArguments(text);
                         qInfo() << argList;
+                       for (auto a: argList)
+                               cout << a.toStdString() << endl;

                         proc.setProgram(argList.takeFirst());
                         proc.setArguments(argList);


and you will see what I mean.

Thanks a lot for being a tester!!!
Yordan

> 
> We don't want to keep the backslash here. We want to remove it before
> passing it as an argument.
> 
> The above should be:
> 
> ("echo", "this " is " a "test")
> 
> (thinking that you put in the outside quotes. In other words, if I have:
> 
>   echo "hello \"there\""
> 
> We should break that up into:
>    arg0=echo
>    arg1=hello "there"
> 
> -- Steve
>