A few months ago I used someone's code on Github and it had this code in it: def build(root) + FileUtils.rm_rf root + self.each do |current| + FileUtils.mkdir_p root + '/' + current[:path] + end + end Link to full code: https://github.com/Bahanix/aMazing/commit/94ae581f... Unfortunately, I didn't properly research what it did and it wiped out my harddrive. I contacted the author and his reason for having rm_rf is: "I built it in mind to replace the target directory in order to be able rerun the script multiple times if the maze was not good." So i asked whether he tested his own program and he said: "I always used it specifying the root of the maze (and not the root of the filesystem), so it has never been a problem to me." Is he telling the truth or is he just trying to placate me because he's scared that i tracked down his email address? What made me suspicious was the fact that in the usage example he used the root directory which made me think he was trying to wipe out my whole harddrive as it wouldn't make sense to have a maze there. Also, when i used it, i set the destination as my desktop. I know this is a stupid thread, but i just want to know whether he really didn't mean any harm or not so that i may be able to forgive him and let this go. And yes, I know I'm an idiot.
on 2017-03-01 10:43
on 2017-03-02 14:35
It is not uncommen to have a rm -rf, or the equivalent in the respective language, in one's program. Needless to say that this **is** very dangerous, but sometimes it is the right thing to do. Of course, with inappropriate parameters, you can wipe out things you want to keep. To erase the whole drive is rare (it means that you would run this code with root permissions, which you certainly won't do unless you have really good reason for it), but it is bad enough if it erases your home directory. There is no general way to safeguard it. If it is an interactive application, it might makes sense to ask for confirmation before doing so, but this isn't always practical either.
on 2017-03-02 14:58
Oh ok, so how was i meant to use the program correctly? I put in my desktop directory as the place to put the maze and it ended up wiping out my desktop and then making the maze. Unfortunately for me, i put pretty much everything on my desktop for convenience sake so I got screwed bad.
on 2017-03-02 15:54
I don't know, what a "Desktop directory" is, but how can it delete everything, unless you run it as root? Actually, if I try out a program which is supposed to create a lot of files/directories, I run it in some temp directory to observe the behaviour, and I actually cd to this directory. In particular in this case, the README - that part which says "Result" - would already suggest that probably nothing is left in the root directory except what maze had put into it. I would see this danger, simply because the documentation doesn't say otherwise: If a program is supposed to create a whole directory structure, and the docs don't say explicitly that nothing is touched of what is already there, I would at least consider the possibility that everything else will be removed. Of course in this case, the program could have checked before, if a non-empty root directory exists, and stop running, unless a special --force flag is supplied on the command line. I would do this if I would write such a program, simply because I could also accidently invoke with a directory which I don't want to erase. But this is just something on Github, and only the first commit (after this, the project seemed to have been abandoned). I wouldn't run such a program without at least having a quick look at the code what it is doing....
on 2017-03-02 16:26
By desktop directory I mean I put my desktop as the destination to create the maze. I don't think i typed in root in the CMD prompt. Also yeah, I realized i should've researched the code before i ran it, i let my guard down and now i've been punished.
on 2017-03-04 00:20
I do not know what the code does, but I remember some years ago when I wrote a ruby app, my supervisor asked me if it is dangerous to run the code. He was quite scared of a problem because he was running as superuser usually, and he was in charge of the local bioinformatics cluster of the company - at that point I also got a bit nervous, so I looked through the code I wrote and I did not see anything where it could screw up. But rm_rf actions CAN be scary - always pay good attention to them! They scare me more than simply file-delete actions. And I also realized that, when it comes to delete actions, in particular removing directories, things can be really, really scary. While it was mentioned to "do not run as superuser", it being a valid comment, let's face it - people may be lazy or also do mistakes. It happens. Ronald F. already gave one example how proper code could handle it - e. g. ask interactively whether you are sure to delete a directory like that. In my own code, I also make sure that '/' can never become a target. (I have no code that would ever warrant getting rid of '/' but I do actually remember that I once, many years ago, also wiped out my hdd; but this was via bash, when I was hitting tab complete but was too swift with the space-character and then hitting enter, I ended up having something like "rm /foo / bar" or something like that. Since that day I usually do backups regularly. :D) Anyway, I think that the code at: https://github.com/Bahanix/aMazing/commit/94ae581f... is bad in general. Or perhaps it is just so very different from how I would write this. I would always use a generic delete/remove method, and inside of that method, handle any additional checks. Such as querying for file permissions and doing any other safeguards. I found that this is usually a lot better than just directly calling FileUtils.rm_rf() which sounds scary. Last but not least, I would recommend you to also look at how many issues a project has; sometimes the more issues that are CLOSED the better, more people to look at a project AND also have a look at rubygems.org - if a project has had lots of releases, it may be that it is of quite good quality. By the way, since you contacted the dude, this actually gave him the possibility to also learn. I am sorry for the loss of your data but I think this also shows that making backups is really important. I don't even trust myself or my own code fully, even though I try to make it as good as possible. :D One day we will be replaced by computers and they will write much better code. Until then, we will write disaster code!
on 2017-03-04 10:11
Robert H. wrote in post #1185641: > In my own code, I also make sure that '/' can never become a target. Of course this doesn't protect agains, for instance, someone using /home or a /home/user/I/think/I/am/safe, which happens to be symlinked to /home .... There is no foolproof safeguard. We just have to be as careful as possible. Of course, taking the viewpoint of a devil's advocate, we can say that wiping out important data is a good test case to measure the quality of our backup-policy. After all, a disk crash could erase the data too. > Anyway, I think that the code at: > > https://github.com/Bahanix/aMazing/commit/94ae581f... > > is bad in general. I would say that the programmer hasn't yet much experience. You can see this also by the lack of comments. And, it is the first version. Maybe the programmer lost interest in maintaining the code. I don't think he would produce such code in a production quality environment, so it was maybe intended as an exercise to program in Ruby. > I would always use a generic delete/remove method, and inside of > that method, handle any additional checks. Such as querying for > file permissions and doing any other safeguards. I found that > this is usually a lot better than just directly calling > FileUtils.rm_rf() which sounds scary. Yes and no. Seeing it from the viewpoint of a Ruby application, this certainly makes sense. I think the majority of rmrf in this world are buried in shell script applications (at least this is the case for my projects), and, while possible, it is much less common to use a generic removal function when doing scripting. Ronald
on 2017-04-04 07:02
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