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-rw-r--r--ChangeLog8
-rwxr-xr-xtests/misc/printf-surprise55
-rw-r--r--tests/test-lib.sh15
3 files changed, 66 insertions, 12 deletions
diff --git a/ChangeLog b/ChangeLog
index 397fc1123..2aece3d40 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,13 @@
2007-11-01 Jim Meyering <meyering@redhat.com>
+ Make the new printf-surprise test more precise.
+ * tests/test-lib.sh (require_ulimit_): New function.
+ * tests/misc/printf-surprise: Use ulimit -v to trigger the fixed bug,
+ and rather than checking printf's exit status (which would go wrong
+ on FreeBSD 6.1, since their printf(3) function doesn't require
+ lots of memory in this case) simply test whether it outputs
+ the first 10 bytes.
+
Accommodate FreeBSD 6.1 hard-link-to-symlink differences.
* tests/cp/same-file: Detect when linking to a symlink links to
the target of the symlink (FreeBSD 6.1 does this, Linux does not),
diff --git a/tests/misc/printf-surprise b/tests/misc/printf-surprise
index 03bc73a41..4e125864a 100755
--- a/tests/misc/printf-surprise
+++ b/tests/misc/printf-surprise
@@ -24,20 +24,51 @@ if test "$VERBOSE" = yes; then
fi
. $srcdir/../test-lib.sh
+require_ulimit_
fail=0
-# The literal width below is 2^31-1.
-# I expect this usage of the printf program to fail.
-# However, it depends on the C library printf function.
-# It could conceivably output "1." and 2GB worth of '0's.
-# You can provoke misbehavior with a much smaller width if you limit
-# virtual memory via, e.g., ulimit -v 10000, but using ulimit would
-# be tricky, since it's not portable.
-"$prog" %.2147483647f 1 > /dev/null 2> err && fail=1
-echo "$prog: cannot perform formatted output: Cannot allocate memory" \
- > exp || framework_failure
-
-compare err exp || fail=1
+# Up to coreutils-6.9, "printf %.Nf 0" would encounter an ENOMEM internal
+# error from glibc's printf(3) function whenever N was large relative to
+# the size of available memory. As of Oct 2007, that internal stream-
+# related failure was not reflected (for any libc I know of) in the usual
+# stream error indicator that is tested by ferror. The result was that
+# while the printf command obviously failed (generated no output),
+# it mistakenly exited successfully (exit status of 0).
+
+# Testing it is tricky, because there is so much variance
+# in quality for this corner of printf(3) implementations.
+# Most implementations do attempt to allocate N bytes of storage.
+# Using the maximum value for N (2^31-1) causes glibc to try to
+# allocate almost 2^64 bytes, while freeBSD 6.1's implementation
+# correctly outputs almost 2GB worth of 0's, which takes too long.
+# We want to test implementations that allocate N bytes, but without
+# triggering the above extremes.
+
+# The compromise is to limit virtual memory to something reasonable,
+# and to make an N-byte-allocating-printf require more than that, thus
+# triggering the printf(3) misbehavior -- which, btw, is required by ISO C99.
+
+( ulimit -v 10000
+ "$prog" %20000000f 0 2>err | head -c 10 >out )
+
+# Map this longer, and rarer, diagnostic to the common one.
+# printf: cannot perform formatted output: Cannot allocate memory" \
+sed 's/cannot perform/write error/' err > k && mv k err
+case $(cat err) in
+ "$prog: write error") diagnostic=y ;;
+ '') diagnostic=n ;;
+ *) diagnostic=unexpected ;;
+esac
+n_out=$(wc -c < out)
+
+case $n_out:$diagnostic in
+ 10:n) ;; # ok, succeeds w/no diagnostic: FreeBSD 6.1
+ 0:y) ;; # ok, glibc, when printf(3) fails with ENOMEM
+
+ # 10:y) ;; # Fail: doesn't happen: nobody succeeds with a diagnostic
+ # 0:n) ;; # Fail pre-patch: no output, no diag
+ *) fail=1;
+esac
(exit $fail); exit $fail
diff --git a/tests/test-lib.sh b/tests/test-lib.sh
index 66fbc1dc4..495fd2a05 100644
--- a/tests/test-lib.sh
+++ b/tests/test-lib.sh
@@ -14,6 +14,21 @@ skip_test_()
(exit 77); exit 77
}
+require_ulimit_()
+{
+ ulimit_works=yes
+ # Expect to be able to exec a program in 10MB of virtual memory,
+ # but not in 20KB. I chose "date". It must not be a shell built-in
+ # function, so you can't use echo, printf, true, etc.
+ # Of course, in coreutils, I could use $top_builddir/src/true,
+ # but this should be able to work for other projects, too.
+ ( ulimit -v 10000; date ) > /dev/null 2>&1 || ulimit_works=no
+ ( ulimit -v 20; date ) > /dev/null 2>&1 && ulimit_works=no
+
+ test $ulimit_works = no \
+ && skip_test_ "this shell lacks ulimit support"
+}
+
uid_is_privileged_()
{
# Make sure id -u succeeds.