[crac] RFR: List open FDs through reading /proc/self/fd [v2]

[Radim Vansa]

> Previously the code was iterating through all possible FD values, up to highest allowed FD number, and required allocation of possibly huge array. Reading /proc/self/fd into a compact array is both more memory efficient and does not require excessive syscalls.

Radim Vansa has updated the pull request incrementally with one additional commit since the last revision:

  Last touches

-------------

Changes:
  - all: https://git.openjdk.org/crac/pull/67/files
  - new: https://git.openjdk.org/crac/pull/67/files/019650b6..e547cc64

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=crac&pr=67&range=01
 - incr: https://webrevs.openjdk.org/?repo=crac&pr=67&range=00-01

  Stats: 7 lines in 1 file changed: 3 ins; 2 del; 2 mod
  Patch: https://git.openjdk.org/crac/pull/67.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/67/head:pull/67

PR: https://git.openjdk.org/crac/pull/67