Thanks.

I'm having a hard time believing that the answer is that non-straightforward. I mean, probably it uses /dev/urandom except in some weird circumstances that can be ruled out given certain basic assumptions (e.g., standard Linux on x86 without any special-purpose entropy-producing hardware). But yeah, this is just my intuition, I can't actually give evidence for this.

I guess one way to find out (for my particular instance) would be to do some kind of tracing of the actual binary I have to see what files it opens. Assuming it does use /dev/urandom, do you have any idea of how much entropy actually needs to be accumulated before creating another wallet?

And I don't suppose there is any easy way to guarantee some other process doesn't suck up the entropy right before bitcoin uses it?

Honestly, it seems like /dev/random would be better for my purposes, since it'll block until it gets enough entropy. I wonder if I can symlink /dev/urandom to /dev/random or something crazy like that.