contrib/reghunt/reg_search

   1 #! /bin/bash
   2
   3 ########################################################################
   4 #
   5 # File:    reg_search
   6 # Author:  Janis Johnson <janis187@us.ibm.com>
   7 # Date:    2002/12/15
   8 #
   9 # Search for a small time interval within a range of dates in which
  10 # results for a test changed, using a binary search.  The functionality
  11 # for getting sources, building the component to test, and running the
  12 # test are in other scripts that are run from here.  Before the search
  13 # begins, we verify that we get the expected behavior for the first and
  14 # last dates.
  15 #
  16 # Define these in a file whose name is the argument to this script:
  17 #   LOW_DATE:   Date string recognized by the date command (local time).
  18 #   HIGH_DATE:  Date string recognized by the date command (local time).
  19 #   REG_UPDATE: Pathname of script to update your source tree; returns
  20 #               zero for success, nonzero for failure.
  21 #   REG_BUILD:  Pathname of script to build enough of the product to run
  22 #               the test; returns zero for success, nonzero for failure.
  23 #   REG_TEST:   Pathname of script to run the test; returns 1 if we
  24 #               should search later dates, 0 if we should search earlier
  25 #               dates.
  26 # Optional:
  27 #   DELTA:      Search to an interval within this many seconds; default
  28 #               is one hour (although 300 works well).
  29 #   REG_FINISH  Pathname of script to call at the end with the two final
  30 #               dates as arguments.
  31 #   SKIP_LOW    If 1, skip verifying the low date of the range;
  32 #               define this only if you're restarting and have already
  33 #               tested the low date.
  34 #   SKIP_HIGH   If 1, skip verifying the high date of the range;
  35 #               define this only if you're restarting and have already
  36 #               tested the high date.
  37 #   FIRST_MID   Use this as the first midpoint, to avoid a midpoint that
  38 #               is known not to build.
  39 #   HAS_CHANGES Pathname of script to report whether the current date has
  40 #               no differences from one of the ends of the current range
  41 #               to skip unnecessary build and testing; default is "true".
  42 #   VERBOSITY   Default is 0, to print only errors and final message.
  43 #   DATE_IN_MSG If set to anything but 0, include the time and date in
  44 #               messages.
  45 #
  46 #
  47 #
  48 # Copyright (c) 2002, 2003, 2005 Free Software Foundation, Inc.
  49 #
  50 # This file is free software; you can redistribute it and/or modify
  51 # it under the terms of the GNU General Public License as published by
  52 # the Free Software Foundation; either version 2 of the License, or
  53 # (at your option) any later version.
  54 #
  55 # This program is distributed in the hope that it will be useful,
  56 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  57 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  58 # GNU General Public License for more details.
  59 #
  60 # For a copy of the GNU General Public License, write the the
  61 # Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  62 # Boston, MA 02111-1307, USA.
  63 #
  64 ########################################################################
  65
  66 ########################################################################
  67 # Functions
  68 ########################################################################
  69
  70 # Issue a message if its verbosity level is high enough.
  71
  72 msg() {
  73   test ${1} -gt ${VERBOSITY}  && return
  74
  75   if [ "x${DATE_IN_MSG}" = "x" ]; then
  76     echo "${2}"
  77   else
  78     echo "`${DATE}`  ${2}"
  79   fi
  80 }
  81
  82 # Issue an error message and exit with a non-zero status.  If there
  83 # is a valid current range whose end points have been tested, report
  84 # it so the user can start again from there.
  85
  86 error() {
  87   msg 0 "error: ${1}"
  88   test ${VALID_RANGE} -eq 1 && \
  89     echo "current range:"
  90     echo "LOW_DATE=\"${LATER_THAN}\""
  91     echo "HIGH_DATE=\"${EARLIER_THAN}\""
  92   exit 1
  93 }
  94
  95 # Turn seconds since the epoch into a date we can use with source
  96 # control tools and report to the user.
  97
  98 make_date() {
  99   MADE_DATE="`${DATE} -u +\"%Y-%m-%d %H:%M %Z\" --date \"1970-01-01 ${1} seconds\"`" \
 100     || error "make_date: date command failed"
 101 }
 102
 103 # Build the components to test using sources as of a particular date and
 104 # run a test case.  Pass each of the scripts the date that we're
 105 # testing; the first one needs it, the others can ignore it if they want.
 106
 107 process_date() {
 108   TEST_DATE="${1}"
 109
 110   ${REG_UPDATE} "${TEST_DATE}" || error "source update failed for ${TEST_DATE}"
 111
 112   # If we're already in a valid range, skip this date if there are no
 113   # differences from either end of the range and adjust LATER.
 114
 115   if [ ${VALID_RANGE} = 1 ]; then
 116     ${HAS_CHANGES} "${TEST_DATE}" "${LATER_THAN}" "${EARLIER_THAN}"
 117     RET=$?
 118     case ${RET} in
 119     0) ;;
 120     1) LATER=1; return;;
 121     2) LATER=0; return;;
 122     *) error "process_date: unexpected return value from ${HAS_CHANGES}";;
 123     esac
 124   fi
 125
 126   ${REG_BUILD} "${TEST_DATE}"  || error "build failed for ${TEST_DATE}"
 127   ${REG_TEST} "${TEST_DATE}"
 128   LATER=$?
 129 }
 130
 131 # Perform a binary search on dates within the range specified by
 132 # the arguments, bounded by the number of seconds in DELTA.
 133
 134 search_dates() {
 135   let LOW=$1
 136   let HIGH=$2
 137   let DIFF=HIGH-LOW
 138
 139   # Get the date in the middle of the range; MID is in seconds since
 140   # the epoch, DATE is readable by humans and tools.  The user can
 141   # override the initial mid date if it is known to have problems,
 142   # e.g., if a build fails for that date.
 143
 144   if [ ${FIRST_MID} -ne 0 ]; then
 145     let MID=${FIRST_MID}
 146   else
 147     let MID=LOW/2+HIGH/2
 148   fi
 149
 150   while [ ${DIFF} -ge ${DELTA} ]; do
 151     make_date ${MID}
 152     TEST_DATE="${MADE_DATE}"
 153
 154     # Test it.
 155
 156     process_date "${TEST_DATE}"
 157
 158     # Narrow the search based on the outcome of testing DATE.
 159
 160     if [ ${LATER} -eq 1 ]; then
 161       msg 1 "search dates later than \"${TEST_DATE}\""
 162       LATER_THAN="${TEST_DATE}"
 163       let LOW=MID
 164     else
 165       msg 1 "search dates earlier than \"${TEST_DATE}\""
 166       EARLIER_THAN="${TEST_DATE}"
 167       let HIGH=MID
 168     fi
 169
 170     let DIFF=HIGH-LOW
 171     let MID=LOW/2+HIGH/2
 172   done
 173 }
 174
 175 ########################################################################
 176 # Main program (so to speak)
 177 ########################################################################
 178
 179 # If DATE isn't defined, use the default date command; the configuration
 180 # file can override this.
 181
 182 if [ "x${DATE}" = "x" ]; then
 183   DATE=date
 184 fi
 185
 186 # The error function uses this.
 187
 188 VALID_RANGE=0
 189
 190 # Process the configuration file.
 191
 192 if [ $# != 1 ]; then
 193   echo Usage: $0 config_file
 194   exit 1
 195 fi
 196
 197 CONFIG=${1}
 198 if [ ! -f ${CONFIG} ]; then
 199   error "configuration file ${CONFIG} does not exist"
 200 fi
 201
 202 # OK, the config file exists.  Source it, make sure required parameters
 203 # are defined and their files exist, and give default values to optional
 204 # parameters.
 205
 206 . ${CONFIG}
 207
 208 test "x${REG_UPDATE}" = "x" && error "REG_UPDATE is not defined"
 209 test "x${REG_BUILD}" = "x" && error "REG_BUILD is not defined"
 210 test "x${REG_TEST}" = "x" && error "REG_TEST is not defined"
 211 test -x ${REG_TEST} || error "REG_TEST is not an executable file"
 212 test "x${SKIP_LOW}" = "x" && SKIP_LOW=0
 213 test "x${SKIP_HIGH}" = "x" && SKIP_HIGH=0
 214 test "x${DELTA}" = "x" && DELTA=3600
 215 test "x${VERBOSITY}" = "x" && VERBOSITY=0
 216 test "x${HAS_CHANGES}" = "x" && HAS_CHANGES=true
 217 test "x${REG_FINISH}" = "x" && REG_FINISH=true
 218
 219 msg 2 "LOW_DATE   = ${LOW_DATE}"
 220 msg 2 "HIGH_DATE  = ${HIGH_DATE}"
 221 msg 2 "REG_UPDATE = ${REG_UPDATE}"
 222 msg 2 "REG_BUILD  = ${REG_BUILD}"
 223 msg 2 "REG_TEST   = ${REG_TEST}"
 224 msg 2 "SKIP_LOW   = ${SKIP_LOW}"
 225 msg 2 "SKIP_HIGH  = ${SKIP_HIGH}"
 226 msg 2 "FIRST_MID  = ${FIRST_MID}"
 227 msg 2 "VERBOSITY  = ${VERBOSITY}"
 228 msg 2 "DELTA      = ${DELTA}"
 229
 230 # Verify that DELTA is at least two minutes.
 231
 232 test ${DELTA} -lt 120 && \
 233   error "DELTA is ${DELTA}, must be at least 120 (two minutes)"
 234
 235 # Change the dates into seconds since the epoch.  This uses an extension
 236 # in GNU date.
 237
 238 LOW_DATE=`${DATE} +%s --date "${LOW_DATE}"` || \
 239   error "date command failed for \"${LOW_DATE}\""
 240 HIGH_DATE=`${DATE} +%s --date "${HIGH_DATE}"` || \
 241   error "date command failed for \"${LOW_DATE}\""
 242
 243 # If FIRST_MID was defined, convert it and make sure it's in the range.
 244
 245 if [ "x${FIRST_MID}" != "x" ]; then
 246   FIRST_MID=`${DATE} +%s --date "${FIRST_MID}"` || \
 247     error "date command failed for \"${FIRST_MID}\""
 248   test ${FIRST_MID} -le ${LOW_DATE}  && \
 249     error "FIRST_MID date is earlier than LOW_DATE"
 250   test ${FIRST_MID} -ge ${HIGH_DATE} && \
 251     error "FIRST_MID is later than HIGH_DATE"
 252 else
 253   FIRST_MID=0
 254 fi
 255
 256 # Keep track of the bounds of the range where the test behavior changes,
 257 # using a human-readable version of each date.
 258
 259 make_date ${LOW_DATE}
 260 LATER_THAN="${MADE_DATE}"
 261 make_date ${HIGH_DATE}
 262 EARLIER_THAN="${MADE_DATE}"
 263
 264 msg 2 "LATER_THAN   = ${LATER_THAN}"
 265 msg 2 "EARLIER_THAN = ${EARLIER_THAN}"
 266
 267 # Verify that the range isn't backwards.
 268
 269 test ${LOW_DATE} -lt ${HIGH_DATE} || error "date range is backwards"
 270
 271 # Verify that the first and last date in the range get the results we
 272 # expect.  If not, quit, because any of several things could be wrong.
 273
 274 if [ ${SKIP_LOW} -eq 0 ]; then
 275   process_date "${LATER_THAN}"
 276   test ${LATER} -ne 1 && \
 277     error "unexpected result for low date ${LATER_THAN}"
 278   msg 1 "result for low date is as expected"
 279 fi
 280
 281 if [ ${SKIP_HIGH} -eq 0 ]; then
 282   process_date "${EARLIER_THAN}"
 283   test ${LATER} -ne 0 && \
 284     error "unexpected result for high date ${EARLIER_THAN}"
 285   msg 1 "result for high date is as expected"
 286 fi
 287
 288 # Search within the range, now that we know that the end points are valid.
 289
 290 VALID_RANGE=1
 291 search_dates ${LOW_DATE} ${HIGH_DATE}
 292
 293 # Report the range that's left to investigate.
 294
 295 echo "Continue search between ${LATER_THAN} and ${EARLIER_THAN}"
 296
 297 # Invoke the optional script to report additional information about
 298 # changes between the two dates.
 299
 300 ${REG_FINISH} "${LATER_THAN}" "${EARLIER_THAN}"