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#! /bin/bash
########################################################################
#
# File: reg_search
# Author: Janis Johnson <janis187@us.ibm.com>
# Date: 2002/12/15
#
# Search for a small time interval within a range of dates in which
# results for a test changed, using a binary search. The functionality
# for getting sources, building the component to test, and running the
# test are in other scripts that are run from here. Before the search
# begins, we verify that we get the expected behavior for the first and
# last dates.
#
# Define these in a file whose name is the argument to this script:
# LOW_DATE: Date string recognized by the date command (local time).
# HIGH_DATE: Date string recognized by the date command (local time).
# REG_UPDATE: Pathname of script to update your source tree; returns
# zero for success, nonzero for failure.
# REG_BUILD: Pathname of script to build enough of the product to run
# the test; returns zero for success, nonzero for failure.
# REG_TEST: Pathname of script to run the test; returns 1 if we
# should search later dates, 0 if we should search earlier
# dates.
# Optional:
# DELTA: Search to an interval within this many seconds; default
# is one hour (although 300 works well).
# REG_FINISH Pathname of script to call at the end with the two final
# dates as arguments.
# SKIP_LOW If 1, skip verifying the low date of the range;
# define this only if you're restarting and have already
# tested the low date.
# SKIP_HIGH If 1, skip verifying the high date of the range;
# define this only if you're restarting and have already
# tested the high date.
# FIRST_MID Use this as the first midpoint, to avoid a midpoint that
# is known not to build.
# HAS_CHANGES Pathname of script to report whether the current date has
# no differences from one of the ends of the current range
# to skip unnecessary build and testing; default is "true".
# VERBOSITY Default is 0, to print only errors and final message.
# DATE_IN_MSG If set to anything but 0, include the time and date in
# messages.
#
#
#
# Copyright (c) 2002, 2003, 2005 Free Software Foundation, Inc.
#
# This file is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# For a copy of the GNU General Public License, write the the
# Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
# Boston, MA 02110-1301, USA.
#
########################################################################
########################################################################
# Functions
########################################################################
# Issue a message if its verbosity level is high enough.
msg() {
test ${1} -gt ${VERBOSITY} && return
if [ "x${DATE_IN_MSG}" = "x" ]; then
echo "${2}"
else
echo "`${DATE}` ${2}"
fi
}
# Issue an error message and exit with a non-zero status. If there
# is a valid current range whose end points have been tested, report
# it so the user can start again from there.
error() {
msg 0 "error: ${1}"
test ${VALID_RANGE} -eq 1 && \
echo "current range:"
echo "LOW_DATE=\"${LATER_THAN}\""
echo "HIGH_DATE=\"${EARLIER_THAN}\""
exit 1
}
# Turn seconds since the epoch into a date we can use with source
# control tools and report to the user.
make_date() {
MADE_DATE="`${DATE} -u +\"%Y-%m-%d %H:%M %Z\" --date \"1970-01-01 ${1} seconds\"`" \
|| error "make_date: date command failed"
}
# Build the components to test using sources as of a particular date and
# run a test case. Pass each of the scripts the date that we're
# testing; the first one needs it, the others can ignore it if they want.
process_date() {
TEST_DATE="${1}"
${REG_UPDATE} "${TEST_DATE}" || error "source update failed for ${TEST_DATE}"
# If we're already in a valid range, skip this date if there are no
# differences from either end of the range and adjust LATER.
if [ ${VALID_RANGE} = 1 ]; then
${HAS_CHANGES} "${TEST_DATE}" "${LATER_THAN}" "${EARLIER_THAN}"
RET=$?
case ${RET} in
0) ;;
1) LATER=1; return;;
2) LATER=0; return;;
*) error "process_date: unexpected return value from ${HAS_CHANGES}";;
esac
fi
${REG_BUILD} "${TEST_DATE}" || error "build failed for ${TEST_DATE}"
${REG_TEST} "${TEST_DATE}"
LATER=$?
}
# Perform a binary search on dates within the range specified by
# the arguments, bounded by the number of seconds in DELTA.
search_dates() {
let LOW=$1
let HIGH=$2
let DIFF=HIGH-LOW
# Get the date in the middle of the range; MID is in seconds since
# the epoch, DATE is readable by humans and tools. The user can
# override the initial mid date if it is known to have problems,
# e.g., if a build fails for that date.
if [ ${FIRST_MID} -ne 0 ]; then
let MID=${FIRST_MID}
else
let MID=LOW/2+HIGH/2
fi
while [ ${DIFF} -ge ${DELTA} ]; do
make_date ${MID}
TEST_DATE="${MADE_DATE}"
# Test it.
process_date "${TEST_DATE}"
# Narrow the search based on the outcome of testing DATE.
if [ ${LATER} -eq 1 ]; then
msg 1 "search dates later than \"${TEST_DATE}\""
LATER_THAN="${TEST_DATE}"
let LOW=MID
else
msg 1 "search dates earlier than \"${TEST_DATE}\""
EARLIER_THAN="${TEST_DATE}"
let HIGH=MID
fi
let DIFF=HIGH-LOW
let MID=LOW/2+HIGH/2
done
}
########################################################################
# Main program (so to speak)
########################################################################
# If DATE isn't defined, use the default date command; the configuration
# file can override this.
if [ "x${DATE}" = "x" ]; then
DATE=date
fi
# The error function uses this.
VALID_RANGE=0
# Process the configuration file.
if [ $# != 1 ]; then
echo Usage: $0 config_file
exit 1
fi
CONFIG=${1}
if [ ! -f ${CONFIG} ]; then
error "configuration file ${CONFIG} does not exist"
fi
# OK, the config file exists. Source it, make sure required parameters
# are defined and their files exist, and give default values to optional
# parameters.
. ${CONFIG}
test "x${REG_UPDATE}" = "x" && error "REG_UPDATE is not defined"
test "x${REG_BUILD}" = "x" && error "REG_BUILD is not defined"
test "x${REG_TEST}" = "x" && error "REG_TEST is not defined"
test -x ${REG_TEST} || error "REG_TEST is not an executable file"
test "x${SKIP_LOW}" = "x" && SKIP_LOW=0
test "x${SKIP_HIGH}" = "x" && SKIP_HIGH=0
test "x${DELTA}" = "x" && DELTA=3600
test "x${VERBOSITY}" = "x" && VERBOSITY=0
test "x${HAS_CHANGES}" = "x" && HAS_CHANGES=true
test "x${REG_FINISH}" = "x" && REG_FINISH=true
msg 2 "LOW_DATE = ${LOW_DATE}"
msg 2 "HIGH_DATE = ${HIGH_DATE}"
msg 2 "REG_UPDATE = ${REG_UPDATE}"
msg 2 "REG_BUILD = ${REG_BUILD}"
msg 2 "REG_TEST = ${REG_TEST}"
msg 2 "SKIP_LOW = ${SKIP_LOW}"
msg 2 "SKIP_HIGH = ${SKIP_HIGH}"
msg 2 "FIRST_MID = ${FIRST_MID}"
msg 2 "VERBOSITY = ${VERBOSITY}"
msg 2 "DELTA = ${DELTA}"
# Verify that DELTA is at least two minutes.
test ${DELTA} -lt 120 && \
error "DELTA is ${DELTA}, must be at least 120 (two minutes)"
# Change the dates into seconds since the epoch. This uses an extension
# in GNU date.
LOW_DATE=`${DATE} +%s --date "${LOW_DATE}"` || \
error "date command failed for \"${LOW_DATE}\""
HIGH_DATE=`${DATE} +%s --date "${HIGH_DATE}"` || \
error "date command failed for \"${LOW_DATE}\""
# If FIRST_MID was defined, convert it and make sure it's in the range.
if [ "x${FIRST_MID}" != "x" ]; then
FIRST_MID=`${DATE} +%s --date "${FIRST_MID}"` || \
error "date command failed for \"${FIRST_MID}\""
test ${FIRST_MID} -le ${LOW_DATE} && \
error "FIRST_MID date is earlier than LOW_DATE"
test ${FIRST_MID} -ge ${HIGH_DATE} && \
error "FIRST_MID is later than HIGH_DATE"
else
FIRST_MID=0
fi
# Keep track of the bounds of the range where the test behavior changes,
# using a human-readable version of each date.
make_date ${LOW_DATE}
LATER_THAN="${MADE_DATE}"
make_date ${HIGH_DATE}
EARLIER_THAN="${MADE_DATE}"
msg 2 "LATER_THAN = ${LATER_THAN}"
msg 2 "EARLIER_THAN = ${EARLIER_THAN}"
# Verify that the range isn't backwards.
test ${LOW_DATE} -lt ${HIGH_DATE} || error "date range is backwards"
# Verify that the first and last date in the range get the results we
# expect. If not, quit, because any of several things could be wrong.
if [ ${SKIP_LOW} -eq 0 ]; then
process_date "${LATER_THAN}"
test ${LATER} -ne 1 && \
error "unexpected result for low date ${LATER_THAN}"
msg 1 "result for low date is as expected"
fi
if [ ${SKIP_HIGH} -eq 0 ]; then
process_date "${EARLIER_THAN}"
test ${LATER} -ne 0 && \
error "unexpected result for high date ${EARLIER_THAN}"
msg 1 "result for high date is as expected"
fi
# Search within the range, now that we know that the end points are valid.
VALID_RANGE=1
search_dates ${LOW_DATE} ${HIGH_DATE}
# Report the range that's left to investigate.
echo "Continue search between ${LATER_THAN} and ${EARLIER_THAN}"
# Invoke the optional script to report additional information about
# changes between the two dates.
${REG_FINISH} "${LATER_THAN}" "${EARLIER_THAN}"