crash_reporter: Ensure crash_sender spread time is not negative

}

# Generate a uniform random number in 0..max-1.

# POSIX arithmetic expansion requires support of at least signed long integers.

# On 32-bit systems, that may mean 32-bit signed integers, in which case the

# 32-bit random number read from /dev/urandom may be interpreted as negative

# when used inside an arithmetic expansion (since the high bit might be set).

# mksh at least is known to behave this way.

# For this case, simply take the absolute value, which will still give a

# roughly uniform random distribution for the modulo (as we are merely ignoring

# the high/sign bit).

# See corresponding Arithmetic Expansion and Arithmetic Expression sections:

# POSIX: http://pubs.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_04

# mksh: http://linux.die.net/man/1/mksh

generate_uniform_random() {

  local max=$1

  local random="$(od -An -N4 -tu /dev/urandom)"

  echo $((random % max))

  echo $(((random < 0 ? -random : random) % max))

}

# Check if sending a crash now does not exceed the maximum 24hr rate and