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| author | Niko Tyni <ntyni@debian.org> | 2012-10-24 21:04:53 +0200 |
|---|---|---|
| committer | Tobias Oetiker <tobi@oetiker.ch> | 2012-10-24 21:04:53 +0200 |
| commit | ef24bb21f91c066129d1fbb4fb72493029a17c6a (patch) | |
| tree | 7a41372896f023cb55bb3486b65648d10a6d198d | |
| parent | 49572f3da6f0e62adbcb3d326c698fad941164f4 (diff) | |
| download | smokeping-ef24bb21f91c066129d1fbb4fb72493029a17c6a.tar.gz smokeping-ef24bb21f91c066129d1fbb4fb72493029a17c6a.tar.xz | |
As spotted by Gert Doering, rand() gives the same results in each
pinger subprocess. This is because they all inherit the same RNG state
from their parent.
Fix this undesired behaviour by reseeding the RNG with the current time
and the process ID.
The argument of srand() shouldn't really matter much on modern Perls,
but we're not very concerned about the quality of the random numbers
either, and time()+$$ should make sure it's different for each process.
| -rw-r--r-- | lib/Smokeping/probes/basefork.pm | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/lib/Smokeping/probes/basefork.pm b/lib/Smokeping/probes/basefork.pm index 0de7b6d..ed8fda8 100644 --- a/lib/Smokeping/probes/basefork.pm +++ b/lib/Smokeping/probes/basefork.pm @@ -201,6 +201,9 @@ sub ping { # we detach from the parent's process group setpgrp(0, $$); + # re-initialize the RNG for each subprocess + srand(time()+$$); + my @times = $self->pingone($t); print join(" ", @times), "\n"; exit; |