From e17e5f40b81447a2af65b0e64a3295d5e2e86753 Mon Sep 17 00:00:00 2001
From: Pádraig Brady <P@draigBrady.com>
Date: Thu, 22 Dec 2016 14:31:44 +0000
Subject: wc: with only --bytes, determine size more efficiently

* src/wc.c (wc): Avoid reading the end of the file
when the size is not a multiple of PAGE_SIZE,
as the special case handling for files in /proc and /sys
is only required when st_size is 0 or a multiple of PAGE_SIZE.
* tests/misc/wc-proc.sh: Add a test case.
---
 tests/misc/wc-proc.sh | 13 +++++++++++++
 1 file changed, 13 insertions(+)

(limited to 'tests/misc')

diff --git a/tests/misc/wc-proc.sh b/tests/misc/wc-proc.sh
index d6a36ba18..c50d7832b 100755
--- a/tests/misc/wc-proc.sh
+++ b/tests/misc/wc-proc.sh
@@ -19,6 +19,7 @@
 . "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
 print_ver_ wc
 
+# Ensure we read() /proc files to determine content length
 for file in /proc/version /sys/kernel/profiling; do
   if test -r $file; then
     cp -f $file copy &&
@@ -29,4 +30,16 @@ for file in /proc/version /sys/kernel/profiling; do
   fi
 done
 
+# Ensure we handle cases where we don't read()
+truncate -s 2 no_read || framework_failure_
+# read() used when multiple of page size
+truncate -s 1048576 do_read || framework_failure_
+wc -c no_read do_read > out || fail=1
+cat <<\EOF > exp
+      2 no_read
+1048576 do_read
+1048578 total
+EOF
+compare exp out || fail=1
+
 Exit $fail
-- 
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