server/tests.at (WITH_STRACE): Factor out the strace(1) machinery.

There's very little noticeable difference in the behaviour: the (usually
empty) directory created for strace(1) to scribble its corefile has a
different name.  The new macro takes care of running the caller's
command in the correct directory, so the (only, currently) call site
doesn't need to worry about that any more.

diff --git a/server/tests.at b/server/tests.at
index 5fcf060..af94847 100644 (file)
--- a/server/tests.at
+++ b/server/tests.at
@@ -42,6 +42,27 @@ m4_define([PKSTREAM],
   [$abs_top_builddir/pkstream/pkstream -b127.0.0.1 -p127.0.0.1])
 m4_define([MITM], [$abs_top_builddir/proxy/tripe-mitm])
 
+## WITH_STRACE(tag, cmd)
+##
+## There's an awful hack here.  If a process running under strace exits with
+## a signal, then strace will kill itself with the same signal -- and
+## therefore clobber the original process's core file.  So we arrange to run
+## strace in one directory and have the child process run in another.
+m4_define([WITH_STRACE],
+[case "${TRIPE_TEST_STRACE-nil}" in
+  nil)
+    $2
+    ;;
+  *)
+    mkdir -p strace-hack.$1/
+    (ulimit -c hard >/dev/null 2>&1
+     sh -c 'cd strace-hack.$1; exec "$[]@"' - \
+       strace -f -o../$1.trace \
+       sh -c 'cd ..; exec "$[]@"' - \
+       $2)
+    ;;
+ esac])
+
 ## Sequences.  (These are used for testing the replay protection machinery.)
 m4_define([R32], [ 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15   dnl
                  16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31])
@@ -84,26 +105,11 @@ mv stdout $1/port
 ## Test body...
 $3
 
-## End of the test, now run the server.  There's an awful hack here.  If a
-## process running under strace exits with a signal, then strace will kill
-## itself with the same signal -- and therefore clobber the original
-## process's core file.  So we arrange to run strace in one directory and
-## have the child process run in another.
+## End of the test, now run the server.
 ) && :; } | {
   cd $1
   echo TRIPE $2 >&2
-  case "${TRIPE_TEST_STRACE-nil}" in
-    nil)
-      TRIPE -d. $2 >server-output.full 2>server-errors
-      ;;
-    *)
-      mkdir -p strace-hack/
-      (cd strace-hack/
-       ulimit -c hard >/dev/null 2>&1
-       strace -f -o ../tripe.trace \
-        TRIPE -d.. $2 >../server-output.full 2>../server-errors)
-      ;;
-  esac
+  WITH_STRACE([tripe], [TRIPE $2 >server-output.full 2>server-errors])
   stat=$?
   echo $stat >server-status
   if test $stat -ne 0; then