I'm assuming we are not talking about recording the eclipse using pro-photographic equipment (which is amply documented elsewhere), but using security cameras, a subject which under-represented in the press.
First off, while it may not normally be good to "point your camera directly at the sun", security cameras withstand such abuses daily, so I wouldnt worry about the camera.
Though you should worry about the picture for sure, because you are likely to get an overexposed, no detail image.
My suggestion would be to invest in one of the newer cameras from Sony/Hik/Dahua that claim > 120db of dynamic range using multiple exposures. Though dynamic range claims can vary greatly, its unlikely that a camera thats *not* at least *claiming* a high number has a chance.
That plus a lens with p-iris control. P-iris should let you have precise electronic control of the iris opening, which will be key as well.
If you are looking to use existing cameras, I would suggest a triply nested tinted dome setup such as
I would get hold of a sheet of Baader AstroSolar Visual Safety film... it's commonly used by telescope boffins (like me) to do solar imaging It's not cheap: a sheet the size of a notebook page is over $20, but it gives a nice neutral white image of the sun, while rejecting something like 99.9998% of the energy. With one sheet you could make a bunch of solar filters for common video cameras.
There are cheaper alternatives to Baader but these get you a rather unsatisfying orange ball vs. the Baader's blue-white... and you'll see more detail with Baader if you have magnification.
I don't work for Baader or anyone connected with Baader... I just like telescopes. My largest is an old timey Celestron 8" Schmidt-Cassegrain: enough light-gathering capability to see the rings of Saturn, small enough to carry around without killing your back.
Please post back on August 22 and let us know how the eclipse went? I'll be here in the far fringe of NY wishing I was in Tennesee. Check out "eclipse2017.org" for details (again - just some fellow geeks: no connection).
Use it at the very front of the lens or optical assembly. You want to keep as much of the energy out of the camera as possible. An open reflector doesn't heat up as much as a closed SCT like my Celestron or in between the lens elements in a typical long camera refractor lens.
You don't need to make a fancy holder : a cardboard sleeve or even duct tape will do. And make sure there aren't any pinholes in it. I'd have to sound like every adult in the Christmas Story movie: "Kid, you'll shoot your eye out!"
Welder's goggle glass is another possibly cheaper filter - use the highest rated one.
Perhaps events like these will encourage others to point their cameras upwards to the heavens.
I just got on B&H to find something and they had a banner on the front page for solar photography. They have a whole section dedicated to how to here.