summaryrefslogtreecommitdiffstats
path: root/tests/dd/no-allocate.sh
diff options
context:
space:
mode:
Diffstat (limited to 'tests/dd/no-allocate.sh')
-rwxr-xr-xtests/dd/no-allocate.sh76
1 files changed, 76 insertions, 0 deletions
diff --git a/tests/dd/no-allocate.sh b/tests/dd/no-allocate.sh
new file mode 100755
index 0000000..f8b7a91
--- /dev/null
+++ b/tests/dd/no-allocate.sh
@@ -0,0 +1,76 @@
+#!/bin/sh
+# make sure that dd doesn't allocate memory unnecessarily
+
+# Copyright (C) 2013-2018 Free Software Foundation, Inc.
+
+# This program 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 3 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.
+
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
+print_ver_ dd
+
+# Determine basic amount of memory needed.
+echo . > f || framework_failure_
+vm=$(get_min_ulimit_v_ timeout 10 dd if=f of=f2 status=none) \
+ || skip_ "this shell lacks ulimit support"
+rm f f2 || framework_failure_
+
+# count and skip are zero, we don't need to allocate memory
+(ulimit -v $vm && dd bs=30M count=0) || fail=1
+(ulimit -v $vm && dd ibs=30M count=0) || fail=1
+(ulimit -v $vm && dd obs=30M count=0) || fail=1
+
+check_dd_seek_alloc() {
+ local file="$1"
+ local buf="$2"
+ test "$file" = 'in' && { dd_file=if; dd_op=skip; }
+ test "$file" = 'out' && { dd_file=of; dd_op=seek; }
+ test "$buf" = 'in' && { dd_buf=ibs; }
+ test "$buf" = 'out' && { dd_buf=obs; }
+ test "$buf" = 'both' && { dd_buf=bs; }
+
+ # Provide input to the "tape"
+ timeout 10 dd count=1 if=/dev/zero of=tape&
+
+ # Allocate buffer and read from the "tape"
+ (ulimit -v $vm \
+ && timeout 10 dd $dd_buf=30M $dd_op=1 count=0 $dd_file=tape)
+ local ret=$?
+
+ # Be defensive in case the tape reader is blocked for some reason
+ test $ret = 124 && framework_failure_
+
+ # This should happen without delay,
+ # and is used to ensure we've not multiple writers to the "tape"
+ wait
+
+ # We want the "tape" reader to fail iff allocating
+ # a large buffer corresponding to the file being read
+ case "$file$buf" in
+ inout|outin) test $ret = 0;;
+ *) test $ret != 0;;
+ esac
+}
+
+# Use a fifo for which seek fails, but read does not.
+# For non seekable output we need to allocate a buffer
+# when simulating seeking with a read.
+if mkfifo tape; then
+ for file in 'in' 'out'; do
+ for buf in 'both' 'in' 'out'; do
+ check_dd_seek_alloc "$file" "$buf" || fail=1
+ done
+ done
+fi
+
+Exit $fail