From d5ad47d000635aa69f2016bf641958c89fba26cc Mon Sep 17 00:00:00 2001
From: Elliott Hughes <enh@google.com>
Date: Mon, 4 Feb 2019 17:43:27 -0800
Subject: sort -o: fix behavior when output file is one of the input files.
Bug: http://b/123902291
---
tests/sort.test | 2 ++
toys/posix/sort.c | 7 ++++---
2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/tests/sort.test b/tests/sort.test
index c71012f0..a40d1b0f 100755
--- a/tests/sort.test
+++ b/tests/sort.test
@@ -13,6 +13,8 @@ testing "stdin" "sort" "a\nb\nc\n" "" "b\na\nc\n"
testing "numeric" "sort -n input" "1\n3\n010\n" "3\n1\n010\n" ""
testing "reverse" "sort -r input" "wook\nwalrus\npoint\npabst\naargh\n" \
"point\nwook\npabst\naargh\nwalrus\n" ""
+testing "sort -o" "sort input -o output && cat output" "a\nb\nc\n" "c\na\nb\n" ""
+testing "sort -o same" "sort input -o input && cat input" "a\nb\nc\n" "c\na\nb\n" ""
# Longish chunk of data re-used by the next few tests. The expected output
# varies, but the input (this) is the same.
diff --git a/toys/posix/sort.c b/toys/posix/sort.c
index 6f5467e1..9433aef2 100644
--- a/toys/posix/sort.c
+++ b/toys/posix/sort.c
@@ -304,9 +304,6 @@ void sort_main(void)
{
int idx, fd = 1;
- // Open output file if necessary.
- if (TT.o) fd = xcreate(TT.o, O_CREAT|O_TRUNC|O_WRONLY, 0666);
-
// Parse -k sort keys.
if (TT.k) {
struct arg_list *arg;
@@ -384,6 +381,10 @@ void sort_main(void)
if (TT.linecount) TT.linecount = jdx+1;
}
+ // Open output file if necessary. We can't do this until we've finished
+ // reading in case the output file is one of the input files.
+ if (TT.o) fd = xcreate(TT.o, O_CREAT|O_TRUNC|O_WRONLY, 0666);
+
// Output result
for (idx = 0; idx<TT.linecount; idx++) {
char *s = TT.lines[idx];
--
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