Issue about Error: ENOENT: no such file or directory, uv_resident_set_memory

[蔡仲明]

I frequently encounter this error message:

 Error: ENOENT: no such file or directory, uv_resident_set_memory

I guess this is some system call or file invisible in the sandbox, but can it just returns some false value so the app won't crash and I need to read and fix?

Thanks.

[Ian Denhardt]

Looks like that function is part of libuv, node's async-io library. I
did a bit of digging, my guess is it's chocking on trying to open
/proc/self/stat:

https://github.com/libuv/libuv/blob/f43c66343316878da09949daf49b515249f71bdf/src/unix/linux-core.c#L459

It should be possible for you to work around this by inserting a dummy
file in your package; the format is documented in proc(5) and it looks
to me like the function is interested in the 'rss' value. I don't know
enough about what's calling that function and how the result is used to
be able to say what the impact of specific values would be though.

I don't think it's a good idea for sandstorm itself to try to spoof
this; we don't have enough visibility into how the information is being
used, and I worry anything we try to do centrally will introduce weird
resource usage bugs elsewhere.

Looks like the cygwin implementation just returns ENOSYS from this
function:

https://github.com/libuv/libuv/blob/e4087dedf837f415056a45a838f639a3d9dc3ced/src/unix/cygwin.c#L38-L41

So presumably libuv has some kind of fallback encoded in it somewhere.

It might be a good idea to open an issue with the libuv project about
running without access to stuff in /proc.

Quoting 蔡仲明 (2018-09-06 04:23:43)

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[Romulus Urakagi Ts'ai 仲明]

Thank you, I'll try if it will work.

Ian Denhardt <i...@zenhack.net> 於 2018年9月7日 週五 上午2:40寫道：

--

Romulus Urakagi Ts'ai