update mktemp to mkdtemp to supress warning mktemp is dangerous

[akoserwal]

warning: the use of mktemp' is dangerous, better use mkstemp' or `mkdtemp'
#11

[highfive]

Thanks for the pull request, and welcome! The Servo team is excited to review your changes, and you should hear from @emilio (or someone else) soon.

[dlrobertson]

mkdtemp creates a directory right? Wouldn't that cause problems with the subsequent new_sockaddr_un call?

[akoserwal]

@dlrobertson: right, it should be mkstemp ?

[dlrobertson]

We're using mkstemp to basically generate a random path. I'm not sure that mkstemp will work either since it actually opens the file. I think we have a few options.

1. Create the path some other way (e.g. with a UUID).
2. use mkdtemp and then use some path on top of that.

[akoserwal]

@dlrobertson : I think, even with option 1 or 2. problem will be with creating the file. As If we using https://doc.rust-lang.org/std/fs/struct.File.html#method.create. it will be in open mode as mkstemp. I am new to rust/system programming. So, I might be having not clear understanding about the entire scenario.

[akoserwal]

@dlrobertson : https://github.com/akoserwal/ipc-channel/blob/feat-mktemp-replacement/src/platform/unix/mod.rs#L603
I tried using uuid & creating a file using File:create & removed mktemp.

[akoserwal]

@dlrobertson :https://github.com/akoserwal/ipc-channel/tree/fix-tempdir-repace-mktemp

[akoserwal]

@dlrobertson : #198 got it working. all test are passing.

[antrik]

@dlrobertson you are evil: first you proposed two different valid approaches, but when he implemented one of them, you suddenly ask why he didn't do it another way... ;-)

[antrik]

@akoserwal you may have figured it out in the meantime; but just to be sure: the issue here is that we do not want to actually create a regular file. Rather, the bind() system call creates a socket special file -- but we need to find a safe location for bind() to put it.

One way to do this is creating a unique and unguessable name up front. (mktemp() is problematic, because the names it creates are not sufficiently unique/unguessable. Your approach using uuid OTOH should have been fine.)

The other way is to safely create a directory for exclusive use (using mkdtemp() or tempfile::TempDir), and then use any name inside that directory for the socket. That's what you are doing in the newer code.

[dlrobertson]

@dlrobertson you are evil: first you proposed two different valid approaches, but when he implemented one of them, you suddenly ask why he didn't do it another way... ;-)

lol yeah. I didn't think of using tempfile early enough. Thought it might make the implementation easier.