tests/init.sh

   1 # source this file; set up for tests
   2
   3 # Copyright (C) 2009-2020 Free Software Foundation, Inc.
   4
   5 # This program is free software: you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License as published by
   7 # the Free Software Foundation, either version 3 of the License, or
   8 # (at your option) any later version.
   9
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU General Public License for more details.
  14
  15 # You should have received a copy of the GNU General Public License
  16 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
  17
  18 # Using this file in a test
  19 # =========================
  20 #
  21 # The typical skeleton of a test looks like this:
  22 #
  23 #   #!/bin/sh
  24 #   . "${srcdir=.}/init.sh"; path_prepend_ .
  25 #   Execute some commands.
  26 #   Note that these commands are executed in a subdirectory, therefore you
  27 #   need to prepend "../" to relative filenames in the build directory.
  28 #   Note that the "path_prepend_ ." is useful only if the body of your
  29 #   test invokes programs residing in the initial directory.
  30 #   For example, if the programs you want to test are in src/, and this test
  31 #   script is named tests/test-1, then you would use "path_prepend_ ../src",
  32 #   or perhaps export PATH='$(abs_top_builddir)/src$(PATH_SEPARATOR)'"$$PATH"
  33 #   to all tests via automake's TESTS_ENVIRONMENT.
  34 #   Set the exit code 0 for success, 77 for skipped, or 1 or other for failure.
  35 #   Use the skip_ and fail_ functions to print a diagnostic and then exit
  36 #   with the corresponding exit code.
  37 #   Exit $?
  38
  39 # Executing a test that uses this file
  40 # ====================================
  41 #
  42 # Running a single test:
  43 #   $ make check TESTS=test-foo.sh
  44 #
  45 # Running a single test, with verbose output:
  46 #   $ make check TESTS=test-foo.sh VERBOSE=yes
  47 #
  48 # Running a single test, keeping the temporary directory:
  49 #   $ make check TESTS=test-foo.sh KEEP=yes
  50 #
  51 # Running a single test, with single-stepping:
  52 #   1. Go into a sub-shell:
  53 #   $ bash
  54 #   2. Set relevant environment variables from TESTS_ENVIRONMENT in the
  55 #      Makefile:
  56 #   $ export srcdir=../../tests # this is an example
  57 #   3. Execute the commands from the test, copy&pasting them one by one:
  58 #   $ . "$srcdir/init.sh"; path_prepend_ .
  59 #   ...
  60 #   4. Finally
  61 #   $ exit
  62
  63 # =============================================================================
  64 # Elementary diagnostics
  65
  66 ME_=`expr "./$0" : '.*/\(.*\)$'`
  67
  68 # Prepare PATH_SEPARATOR.
  69 # The user is always right.
  70 if test "${PATH_SEPARATOR+set}" != set; then
  71   # Determine PATH_SEPARATOR by trying to find /bin/sh in a PATH which
  72   # contains only /bin. Note that ksh looks also at the FPATH variable,
  73   # so we have to set that as well for the test.
  74   PATH_SEPARATOR=:
  75   (PATH='/bin;/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 \
  76     && { (PATH='/bin:/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 \
  77            || PATH_SEPARATOR=';'
  78        }
  79 fi
  80
  81 # We use a trap below for cleanup.  This requires us to go through
  82 # hoops to get the right exit status transported through the handler.
  83 # So use 'Exit STATUS' instead of 'exit STATUS' inside of the tests.
  84 # Turn off errexit here so that we don't trip the bug with OSF1/Tru64
  85 # sh inside this function.
  86 Exit () { set +e; (exit $1); exit $1; }
  87
  88 # Print warnings (e.g., about skipped and failed tests) to this file number.
  89 # Override by defining to say, 9, in init.cfg, and putting say,
  90 #   export ...ENVVAR_SETTINGS...; $(SHELL) 9>&2
  91 # in the definition of TESTS_ENVIRONMENT in your tests/Makefile.am file.
  92 # This is useful when using automake's parallel tests mode, to print
  93 # the reason for skip/failure to console, rather than to the .log files.
  94 : ${stderr_fileno_=2}
  95
  96 # Note that correct expansion of "$*" depends on IFS starting with ' '.
  97 # Always write the full diagnostic to stderr.
  98 # When stderr_fileno_ is not 2, also emit the first line of the
  99 # diagnostic to that file descriptor.
 100 warn_ ()
 101 {
 102   # If IFS does not start with ' ', set it and emit the warning in a subshell.
 103   case $IFS in
 104     ' '*) printf '%s\n' "$*" >&2
 105           test $stderr_fileno_ = 2 \
 106             || { printf '%s\n' "$*" | sed 1q >&$stderr_fileno_ ; } ;;
 107     *) (IFS=' '; warn_ "$@");;
 108   esac
 109 }
 110 fail_ () { warn_ "$ME_: failed test: $@"; Exit 1; }
 111 skip_ () { warn_ "$ME_: skipped test: $@"; Exit 77; }
 112 fatal_ () { warn_ "$ME_: hard error: $@"; Exit 99; }
 113 framework_failure_ () { warn_ "$ME_: set-up failure: $@"; Exit 99; }
 114
 115 # =============================================================================
 116 # Ensure the shell supports modern syntax.
 117
 118 # Sanitize this shell to POSIX mode, if possible.
 119 DUALCASE=1; export DUALCASE
 120 if test -n "${ZSH_VERSION+set}" && (emulate sh) >/dev/null 2>&1; then
 121   emulate sh
 122   NULLCMD=:
 123   alias -g '${1+"$@"}'='"$@"'
 124   setopt NO_GLOB_SUBST
 125 else
 126   case `(set -o) 2>/dev/null` in
 127     *posix*) set -o posix ;;
 128   esac
 129 fi
 130
 131 # We require $(...) support unconditionally.
 132 # We require that the printf built-in work correctly regarding octal escapes;
 133 # this eliminates /bin/sh on AIX 7.2.
 134 # We require non-surprising "local" semantics (this eliminates dash).
 135 # This takes the admittedly draconian step of eliminating dash, because the
 136 # assignment tab=$(printf '\t') works fine, yet preceding it with "local "
 137 # transforms it into an assignment that sets the variable to the empty string.
 138 # That is too counter-intuitive, and can lead to subtle run-time malfunction.
 139 # The example below is less subtle in that with dash, it evokes the run-time
 140 # exception "dash: 1: local: 1: bad variable name".
 141 # We require a few additional shell features only when $EXEEXT is nonempty,
 142 # in order to support automatic $EXEEXT emulation:
 143 # - hyphen-containing alias names
 144 # - we prefer to use ${var#...} substitution, rather than having
 145 #   to work around lack of support for that feature.
 146 # The following code attempts to find a shell with support for these features.
 147 # If the current shell passes the test, we're done.  Otherwise, test other
 148 # shells until we find one that passes.  If one is found, re-exec it.
 149 # If no acceptable shell is found, skip the current test.
 150 #
 151 # The "...set -x; P=1 true 2>err..." test is to disqualify any shell that
 152 # emits "P=1" into err, as /bin/sh from SunOS 5.11 and OpenBSD 4.7 do.
 153 #
 154 # Use "9" to indicate success (rather than 0), in case some shell acts
 155 # like Solaris 10's /bin/sh but exits successfully instead of with status 2.
 156
 157 # Eval this code in a subshell to determine a shell's suitability.
 158 # 10 - passes all tests; ok to use
 159 #  9 - ok, but enabling "set -x" corrupts app stderr; prefer higher score
 160 #  ? - not ok
 161 gl_shell_test_script_='
 162 test $(echo y) = y || exit 1
 163 LC_ALL=en_US.UTF-8 printf "\\351" 2>/dev/null \
 164   | LC_ALL=C tr "\\351" x | LC_ALL=C grep "^x$" > /dev/null \
 165   || exit 1
 166 printf "\\351" 2>/dev/null \
 167   | LC_ALL=C tr "\\351" x | LC_ALL=C grep "^x$" > /dev/null \
 168   || exit 1
 169 f_local_() { local v=1; }; f_local_ || exit 1
 170 f_dash_local_fail_() { local t=$(printf " 1"); }; f_dash_local_fail_
 171 score_=10
 172 if test "$VERBOSE" = yes; then
 173   test -n "$( (exec 3>&1; set -x; P=1 true 2>&3) 2> /dev/null)" && score_=9
 174 fi
 175 test -z "$EXEEXT" && exit $score_
 176 shopt -s expand_aliases
 177 alias a-b="echo zoo"
 178 v=abx
 179      test ${v%x} = ab \
 180   && test ${v#a} = bx \
 181   && test $(a-b) = zoo \
 182   && exit $score_
 183 '
 184
 185 if test "x$1" = "x--no-reexec"; then
 186   shift
 187 else
 188   # Assume a working shell.  Export to subshells (setup_ needs this).
 189   gl_set_x_corrupts_stderr_=false
 190   export gl_set_x_corrupts_stderr_
 191
 192   # Record the first marginally acceptable shell.
 193   marginal_=
 194
 195   # Search for a shell that meets our requirements.
 196   for re_shell_ in __current__ "${CONFIG_SHELL:-no_shell}" \
 197       /bin/sh bash dash zsh pdksh fail
 198   do
 199     test "$re_shell_" = no_shell && continue
 200
 201     # If we've made it all the way to the sentinel, "fail" without
 202     # finding even a marginal shell, skip this test.
 203     if test "$re_shell_" = fail; then
 204       test -z "$marginal_" && skip_ failed to find an adequate shell
 205       re_shell_=$marginal_
 206       break
 207     fi
 208
 209     # When testing the current shell, simply "eval" the test code.
 210     # Otherwise, run it via $re_shell_ -c ...
 211     if test "$re_shell_" = __current__; then
 212       # 'eval'ing this code makes Solaris 10's /bin/sh exit with
 213       # $? set to 2.  It does not evaluate any of the code after the
 214       # "unexpected" first '('.  Thus, we must run it in a subshell.
 215       ( eval "$gl_shell_test_script_" ) > /dev/null 2>&1
 216     else
 217       "$re_shell_" -c "$gl_shell_test_script_" 2>/dev/null
 218     fi
 219
 220     st_=$?
 221
 222     # $re_shell_ works just fine.  Use it.
 223     if test $st_ = 10; then
 224       gl_set_x_corrupts_stderr_=false
 225       break
 226     fi
 227
 228     # If this is our first marginally acceptable shell, remember it.
 229     if test "$st_:$marginal_" = 9: ; then
 230       marginal_="$re_shell_"
 231       gl_set_x_corrupts_stderr_=true
 232     fi
 233   done
 234
 235   if test "$re_shell_" != __current__; then
 236     # Found a usable shell.  Preserve -v and -x.
 237     case $- in
 238       *v*x* | *x*v*) opts_=-vx ;;
 239       *v*) opts_=-v ;;
 240       *x*) opts_=-x ;;
 241       *) opts_= ;;
 242     esac
 243     re_shell=$re_shell_
 244     export re_shell
 245     exec "$re_shell_" $opts_ "$0" --no-reexec "$@"
 246     echo "$ME_: exec failed" 1>&2
 247     exit 127
 248   fi
 249 fi
 250
 251 # =============================================================================
 252 # Ensure the shell behaves reasonably.
 253
 254 # If this is bash, turn off all aliases.
 255 test -n "$BASH_VERSION" && unalias -a
 256
 257 # Note that when supporting $EXEEXT (transparently mapping from PROG_NAME to
 258 # PROG_NAME.exe), we want to support hyphen-containing names like test-acos.
 259 # That is part of the shell-selection test above.  Why use aliases rather
 260 # than functions?  Because support for hyphen-containing aliases is more
 261 # widespread than that for hyphen-containing function names.
 262 test -n "$EXEEXT" && test -n "$BASH_VERSION" && shopt -s expand_aliases
 263
 264 # =============================================================================
 265 # Creating a temporary directory (needed by the core test framework)
 266
 267 # Create a temporary directory, much like mktemp -d does.
 268 # Written by Jim Meyering.
 269 #
 270 # Usage: mktempd_ /tmp phoey.XXXXXXXXXX
 271 #
 272 # First, try to use the mktemp program.
 273 # Failing that, we'll roll our own mktemp-like function:
 274 #  - try to get random bytes from /dev/urandom
 275 #  - failing that, generate output from a combination of quickly-varying
 276 #      sources and gzip.  Ignore non-varying gzip header, and extract
 277 #      "random" bits from there.
 278 #  - given those bits, map to file-name bytes using tr, and try to create
 279 #      the desired directory.
 280 #  - make only $MAX_TRIES_ attempts
 281
 282 # Helper function.  Print $N pseudo-random bytes from a-zA-Z0-9.
 283 rand_bytes_ ()
 284 {
 285   n_=$1
 286
 287   # Maybe try openssl rand -base64 $n_prime_|tr '+/=\012' abcd first?
 288   # But if they have openssl, they probably have mktemp, too.
 289
 290   chars_=abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789
 291   dev_rand_=/dev/urandom
 292   if test -r "$dev_rand_"; then
 293     # Note: 256-length($chars_) == 194; 3 copies of $chars_ is 186 + 8 = 194.
 294     dd ibs=$n_ count=1 if=$dev_rand_ 2>/dev/null \
 295       | LC_ALL=C tr -c $chars_ 01234567$chars_$chars_$chars_
 296     return
 297   fi
 298
 299   n_plus_50_=`expr $n_ + 50`
 300   cmds_='date; date +%N; free; who -a; w; ps auxww; ps -ef'
 301   data_=` (eval "$cmds_") 2>&1 | gzip `
 302
 303   # Ensure that $data_ has length at least 50+$n_
 304   while :; do
 305     len_=`echo "$data_"|wc -c`
 306     test $n_plus_50_ -le $len_ && break;
 307     data_=` (echo "$data_"; eval "$cmds_") 2>&1 | gzip `
 308   done
 309
 310   echo "$data_" \
 311     | dd bs=1 skip=50 count=$n_ 2>/dev/null \
 312     | LC_ALL=C tr -c $chars_ 01234567$chars_$chars_$chars_
 313 }
 314
 315 mktempd_ ()
 316 {
 317   case $# in
 318   2);;
 319   *) fail_ "Usage: mktempd_ DIR TEMPLATE";;
 320   esac
 321
 322   destdir_=$1
 323   template_=$2
 324
 325   MAX_TRIES_=4
 326
 327   # Disallow any trailing slash on specified destdir:
 328   # it would subvert the post-mktemp "case"-based destdir test.
 329   case $destdir_ in
 330   / | //) destdir_slash_=$destdir;;
 331   */) fail_ "invalid destination dir: remove trailing slash(es)";;
 332   *) destdir_slash_=$destdir_/;;
 333   esac
 334
 335   case $template_ in
 336   *XXXX) ;;
 337   *) fail_ \
 338        "invalid template: $template_ (must have a suffix of at least 4 X's)";;
 339   esac
 340
 341   # First, try to use mktemp.
 342   d=`unset TMPDIR; { mktemp -d -t -p "$destdir_" "$template_"; } 2>/dev/null` &&
 343
 344   # The resulting name must be in the specified directory.
 345   case $d in "$destdir_slash_"*) :;; *) false;; esac &&
 346
 347   # It must have created the directory.
 348   test -d "$d" &&
 349
 350   # It must have 0700 permissions.  Handle sticky "S" bits.
 351   perms=`ls -dgo "$d" 2>/dev/null` &&
 352   case $perms in drwx--[-S]---*) :;; *) false;; esac && {
 353     echo "$d"
 354     return
 355   }
 356
 357   # If we reach this point, we'll have to create a directory manually.
 358
 359   # Get a copy of the template without its suffix of X's.
 360   base_template_=`echo "$template_"|sed 's/XX*$//'`
 361
 362   # Calculate how many X's we've just removed.
 363   template_length_=`echo "$template_" | wc -c`
 364   nx_=`echo "$base_template_" | wc -c`
 365   nx_=`expr $template_length_ - $nx_`
 366
 367   err_=
 368   i_=1
 369   while :; do
 370     X_=`rand_bytes_ $nx_`
 371     candidate_dir_="$destdir_slash_$base_template_$X_"
 372     err_=`mkdir -m 0700 "$candidate_dir_" 2>&1` \
 373       && { echo "$candidate_dir_"; return; }
 374     test $MAX_TRIES_ -le $i_ && break;
 375     i_=`expr $i_ + 1`
 376   done
 377   fail_ "$err_"
 378 }
 379
 380 # =============================================================================
 381 # Core test framework
 382
 383 # An arbitrary prefix to help distinguish test directories.
 384 testdir_prefix_ () { printf gt; }
 385
 386 # Set up the environment for the test to run in.
 387 setup_ ()
 388 {
 389   if test "$VERBOSE" = yes; then
 390     # Test whether set -x may cause the selected shell to corrupt an
 391     # application's stderr.  Many do, including zsh-4.3.10 and the /bin/sh
 392     # from SunOS 5.11, OpenBSD 4.7 and Irix 5.x and 6.5.
 393     # If enabling verbose output this way would cause trouble, simply
 394     # issue a warning and refrain.
 395     if $gl_set_x_corrupts_stderr_; then
 396       warn_ "using SHELL=$SHELL with 'set -x' corrupts stderr"
 397     else
 398       set -x
 399     fi
 400   fi
 401
 402   initial_cwd_=$PWD
 403
 404   # Create and enter the temporary directory.
 405   pfx_=`testdir_prefix_`
 406   test_dir_=`mktempd_ "$initial_cwd_" "$pfx_-$ME_.XXXX"` \
 407     || fail_ "failed to create temporary directory in $initial_cwd_"
 408   cd "$test_dir_" || fail_ "failed to cd to temporary directory"
 409   # Set variables srcdir, builddir, for the convenience of the test.
 410   case $srcdir in
 411     /* | ?:*) ;;
 412     *) srcdir="../$srcdir" ;;
 413   esac
 414   builddir=".."
 415   export srcdir builddir
 416
 417   # As autoconf-generated configure scripts do, ensure that IFS
 418   # is defined initially, so that saving and restoring $IFS works.
 419   gl_init_sh_nl_='
 420 '
 421   IFS=" ""      $gl_init_sh_nl_"
 422
 423   # This trap statement, along with a trap on 0 below, ensure that the
 424   # temporary directory, $test_dir_, is removed upon exit as well as
 425   # upon receipt of any of the listed signals.
 426   for sig_ in 1 2 3 13 15; do
 427     eval "trap 'Exit $(expr $sig_ + 128)' $sig_"
 428   done
 429 }
 430
 431 # This is a stub function that is run upon trap (upon regular exit and
 432 # interrupt).  Override it with a per-test function, e.g., to unmount
 433 # a partition, or to undo any other global state changes.
 434 cleanup_ () { :; }
 435
 436 # Run the user-overridable cleanup_ function, remove the temporary
 437 # directory and exit with the incoming value of $?.
 438 remove_tmp_ ()
 439 {
 440   __st=$?
 441   cleanup_
 442   if test "$KEEP" = yes; then
 443     echo "Not removing temporary directory $test_dir_"
 444   else
 445     # cd out of the directory we're about to remove
 446     cd "$initial_cwd_" || cd / || cd /tmp
 447     chmod -R u+rwx "$test_dir_"
 448     # If removal fails and exit status was to be 0, then change it to 1.
 449     rm -rf "$test_dir_" || { test $__st = 0 && __st=1; }
 450   fi
 451   exit $__st
 452 }
 453
 454 # =============================================================================
 455 # Prepending directories to PATH
 456
 457 # Given a directory name, DIR, if every entry in it that matches *.exe
 458 # contains only the specified bytes (see the case stmt below), then print
 459 # a space-separated list of those names and return 0.  Otherwise, don't
 460 # print anything and return 1.  Naming constraints apply also to DIR.
 461 find_exe_basenames_ ()
 462 {
 463   feb_dir_=$1
 464   feb_fail_=0
 465   feb_result_=
 466   feb_sp_=
 467   for feb_file_ in $feb_dir_/*.exe; do
 468     # If there was no *.exe file, or there existed a file named "*.exe" that
 469     # was deleted between the above glob expansion and the existence test
 470     # below, just skip it.
 471     test "x$feb_file_" = "x$feb_dir_/*.exe" && test ! -f "$feb_file_" \
 472       && continue
 473     # Exempt [.exe, since we can't create a function by that name, yet
 474     # we can't invoke [ by PATH search anyways due to shell builtins.
 475     test "x$feb_file_" = "x$feb_dir_/[.exe" && continue
 476     case $feb_file_ in
 477       *[!-a-zA-Z/0-9_.+]*) feb_fail_=1; break;;
 478       *) # Remove leading file name components as well as the .exe suffix.
 479          feb_file_=${feb_file_##*/}
 480          feb_file_=${feb_file_%.exe}
 481          feb_result_="$feb_result_$feb_sp_$feb_file_";;
 482     esac
 483     feb_sp_=' '
 484   done
 485   test $feb_fail_ = 0 && printf %s "$feb_result_"
 486   return $feb_fail_
 487 }
 488
 489 # Consider the files in directory, $1.
 490 # For each file name of the form PROG.exe, create an alias named
 491 # PROG that simply invokes PROG.exe, then return 0.  If any selected
 492 # file name or the directory name, $1, contains an unexpected character,
 493 # define no alias and return 1.
 494 create_exe_shims_ ()
 495 {
 496   case $EXEEXT in
 497     '') return 0 ;;
 498     .exe) ;;
 499     *) echo "$0: unexpected \$EXEEXT value: $EXEEXT" 1>&2; return 1 ;;
 500   esac
 501
 502   base_names_=`find_exe_basenames_ $1` \
 503     || { echo "$0 (exe_shim): skipping directory: $1" 1>&2; return 0; }
 504
 505   if test -n "$base_names_"; then
 506     for base_ in $base_names_; do
 507       alias "$base_"="$base_$EXEEXT"
 508     done
 509   fi
 510
 511   return 0
 512 }
 513
 514 # Use this function to prepend to PATH an absolute name for each
 515 # specified, possibly-$initial_cwd_-relative, directory.
 516 path_prepend_ ()
 517 {
 518   while test $# != 0; do
 519     path_dir_=$1
 520     case $path_dir_ in
 521       '') fail_ "invalid path dir: '$1'";;
 522       /* | ?:*) abs_path_dir_=$path_dir_;;
 523       *) abs_path_dir_=$initial_cwd_/$path_dir_;;
 524     esac
 525     case $abs_path_dir_ in
 526       *$PATH_SEPARATOR*) fail_ "invalid path dir: '$abs_path_dir_'";;
 527     esac
 528     PATH="$abs_path_dir_$PATH_SEPARATOR$PATH"
 529
 530     # Create an alias, FOO, for each FOO.exe in this directory.
 531     create_exe_shims_ "$abs_path_dir_" \
 532       || fail_ "something failed (above): $abs_path_dir_"
 533     shift
 534   done
 535   export PATH
 536 }
 537
 538 # =============================================================================
 539 # Convenience environment variables for the tests
 540
 541 # -----------------------------------------------------------------------------
 542
 543 # Enable glibc's malloc-perturbing option.
 544 # This is useful for exposing code that depends on the fact that
 545 # malloc-related functions often return memory that is mostly zeroed.
 546 # If you have the time and cycles, use valgrind to do an even better job.
 547 : ${MALLOC_PERTURB_=87}
 548 export MALLOC_PERTURB_
 549
 550 # -----------------------------------------------------------------------------
 551
 552 # The interpreter for Bourne-shell scripts.
 553 # No special standards compatibility requirements.
 554 # Some environments, such as Android, don't have /bin/sh.
 555 if test -f /bin/sh$EXEEXT; then
 556   BOURNE_SHELL=/bin/sh
 557 else
 558   BOURNE_SHELL=sh
 559 fi
 560
 561 # =============================================================================
 562 # Convenience functions for the tests
 563
 564 # -----------------------------------------------------------------------------
 565 # Return value checking
 566
 567 # This is used to simplify checking of the return value
 568 # which is useful when ensuring a command fails as desired.
 569 # I.e., just doing `command ... &&fail=1` will not catch
 570 # a segfault in command for example.  With this helper you
 571 # instead check an explicit exit code like
 572 #   returns_ 1 command ... || fail
 573 returns_ () {
 574   # Disable tracing so it doesn't interfere with stderr of the wrapped command
 575   { set +x; } 2>/dev/null
 576
 577   local exp_exit="$1"
 578   shift
 579   "$@"
 580   test $? -eq $exp_exit && ret_=0 || ret_=1
 581
 582   if test "$VERBOSE" = yes && test "$gl_set_x_corrupts_stderr_" = false; then
 583     set -x
 584   fi
 585   { return $ret_; } 2>/dev/null
 586 }
 587
 588 # -----------------------------------------------------------------------------
 589 # Text file comparison
 590
 591 # Emit a header similar to that from diff -u;  Print the simulated "diff"
 592 # command so that the order of arguments is clear.  Don't bother with @@ lines.
 593 emit_diff_u_header_ ()
 594 {
 595   printf '%s\n' "diff -u $*" \
 596     "--- $1     1970-01-01" \
 597     "+++ $2     1970-01-01"
 598 }
 599
 600 # Arrange not to let diff or cmp operate on /dev/null,
 601 # since on some systems (at least OSF/1 5.1), that doesn't work.
 602 # When there are not two arguments, or no argument is /dev/null, return 2.
 603 # When one argument is /dev/null and the other is not empty,
 604 # cat the nonempty file to stderr and return 1.
 605 # Otherwise, return 0.
 606 compare_dev_null_ ()
 607 {
 608   test $# = 2 || return 2
 609
 610   if test "x$1" = x/dev/null; then
 611     test -s "$2" || return 0
 612     emit_diff_u_header_ "$@"; sed 's/^/+/' "$2"
 613     return 1
 614   fi
 615
 616   if test "x$2" = x/dev/null; then
 617     test -s "$1" || return 0
 618     emit_diff_u_header_ "$@"; sed 's/^/-/' "$1"
 619     return 1
 620   fi
 621
 622   return 2
 623 }
 624
 625 for diff_opt_ in -u -U3 -c '' no; do
 626   test "$diff_opt_" != no &&
 627     diff_out_=`exec 2>/dev/null; diff $diff_opt_ "$0" "$0" < /dev/null` &&
 628     break
 629 done
 630 if test "$diff_opt_" != no; then
 631   if test -z "$diff_out_"; then
 632     compare_ () { diff $diff_opt_ "$@"; }
 633   else
 634     compare_ ()
 635     {
 636       # If no differences were found, AIX and HP-UX 'diff' produce output
 637       # like "No differences encountered".  Hide this output.
 638       diff $diff_opt_ "$@" > diff.out
 639       diff_status_=$?
 640       test $diff_status_ -eq 0 || cat diff.out || diff_status_=2
 641       rm -f diff.out || diff_status_=2
 642       return $diff_status_
 643     }
 644   fi
 645 elif cmp -s /dev/null /dev/null 2>/dev/null; then
 646   compare_ () { cmp -s "$@"; }
 647 else
 648   compare_ () { cmp "$@"; }
 649 fi
 650
 651 # Usage: compare EXPECTED ACTUAL
 652 #
 653 # Given compare_dev_null_'s preprocessing, defer to compare_ if 2 or more.
 654 # Otherwise, propagate $? to caller: any diffs have already been printed.
 655 compare ()
 656 {
 657   # This looks like it can be factored to use a simple "case $?"
 658   # after unchecked compare_dev_null_ invocation, but that would
 659   # fail in a "set -e" environment.
 660   if compare_dev_null_ "$@"; then
 661     return 0
 662   else
 663     case $? in
 664       1) return 1;;
 665       *) compare_ "$@";;
 666     esac
 667   fi
 668 }
 669
 670 # -----------------------------------------------------------------------------
 671
 672 # If you want to override the testdir_prefix_ function,
 673 # or to add more utility functions, use this file.
 674 test -f "$srcdir/init.cfg" \
 675   && . "$srcdir/init.cfg"
 676
 677 # =============================================================================
 678 # Set up the environment for the test to run in.
 679
 680 setup_ "$@"
 681 # This trap is here, rather than in the setup_ function, because some
 682 # shells run the exit trap at shell function exit, rather than script exit.
 683 trap remove_tmp_ 0