Re: [PATCH 1/7] add random_pathstring()

On Mon, Mar 16, 2015 at 01:25:21PM -0700, [email protected] wrote:
 > From: Tyson Smith <[email protected]>
 > 
 > This will generate a path that will likely not exist but may
 > look somewhat valid or totally crazy depending on rand.

We kinda tried this before. It stressed the negative dentry code
a little (perhaps a little too much tbh), but never really found
anything interesting, and just caused trinity to crap garbage
filenames all over the tmp dir.

Not sure it's worth trying this again. If we do, we should
make it a lot less likely to happen, like 1 in a 100 or something.


 > +	switch(rand() % 5) {

Someone recently added a handy ONE_IN macro :)

 > +	case 0:
 > +		// single repeating random ASCII character
 > +		(void) memset(path, (rand() % 95) + 32, rand() % len);
 > +		path[len-1] = '\0';
 > +		break;
 > +	case 1:
 > +		// random ASCII characters 32(space) -> 126(~)
 > +		for (i=0; i < len; i++)
 > +			path[i] = (char) ((rand() % 95) + 32);
 > +		path[len-1] = '\0';
 > +		break;
 > +	case 2:
 > +		// random . or /
 > +		for (i=0; i < len; i++)
 > +			path[i] = RAND_BOOL() ? '.' : '/';
 > +		path[len-1] = '\0';
 > +		break;
 > +	case 3:
 > +		// format strings
 > +		for (i=0; i < (len - 2); i+=2) {
 > +			path[i] = '%';
 > +			path[i+1] = fmts[rand() % 3];
 > +		}
 > +		path[len-1] = '\0';
 > +		break;
 > +	case 4:
 > +		// junk
 > +		for (i=0; i < len; i++)
 > +			path[i] = (char) RAND_BYTE();
 > +		path[len-1] = '\0';
 > +		break;
 > +	}

This should probably just be a generate_rand_bytes() call,
with enhancements to that function if necessary.

	Dave