Created attachment 292157 [details]
Demo program

Shells must read in single-byte reads, and that procfs violates the normal filesystem expectations, and that the C sample program demonstrates that behavior.

My use case is with the mksh shell, for example:

IFS= read -r < /proc/sys/kernel/random/poolsize size; echo $size

Gives:
4

Then it returns with 1 (exit status).

The default value at the poolsize is: 4096