Foundation attempts to read from /dev/urandom

[MaxDesiatov]

It was discovered by @kateinoigakukun. See this line, which causes exceptions on WASI.

[j-f1]

This can be fixed by implementing a platform-specific version of read_random using random_get. It might be as simple as #define read_random random_get.

[kateinoigakukun]

This is also resolved by swiftwasm/swift-corelibs-foundation#323

[MaxDesiatov]

Is there any substantial difference between getentropy and random_get? Why would we use one over the other?

[kateinoigakukun]

getentropy internally use random_get. https://github.com/WebAssembly/wasi-libc/blob/main/libc-bottom-half/sources/getentropy.c

getentropy is more portable API than wasi specific random_get, so I prefer it.