Files
nixpkgs/pkgs/tools/misc/coreutils/tail.patch
T

51 lines
2.0 KiB
Diff

(NB: we omit the new test, in order to avoid rerunning autoconf.)
From 914972e80dbf82aac9ffe3ff1f67f1028e1a788b Mon Sep 17 00:00:00 2001
From: Hannes Braun <hannes@hannesbraun.net>
Date: Wed, 24 Sep 2025 21:20:49 +0200
Subject: [PATCH] tail: fix tailing larger number of lines in regular files
* src/tail.c (file_lines): Seek to the previous block instead of the
beginning (or a little before) of the block that was just scanned.
Otherwise, the same block is read and scanned (at least partially)
again. This bug was introduced by commit v9.7-219-g976f8abc1.
* tests/tail/basic-seek.sh: Add a new test.
* tests/local.mk: Reference the new test.
* NEWS: mention the bug fix.
---
NEWS | 4 ++++
src/tail.c | 2 +-
tests/local.mk | 1 +
tests/tail/basic-seek.sh | 28 ++++++++++++++++++++++++++++
4 files changed, 34 insertions(+), 1 deletion(-)
create mode 100755 tests/tail/basic-seek.sh
diff --git a/NEWS b/NEWS
index 7a1a73113e839f010aa6c734e6f07da68827b953..dc1d26879327761d35499815776477771758edd4 100644
--- a/NEWS
+++ b/NEWS
@@ -7,6 +7,10 @@ GNU coreutils NEWS -*- outline -*-
`basenc --base58` would not operate correctly with input > 15561475 bytes.
[bug introduced with --base58 in coreutils-9.8]
+ 'tail' outputs the correct number of lines again for non-small -n values.
+ Previously it may have output too few lines.
+ [bug introduced in coreutils-9.8]
+
* Noteworthy changes in release 9.8 (2025-09-22) [stable]
diff --git a/src/tail.c b/src/tail.c
index b8bef1d91cdb6cde2b666b6c1575376e075eaeb8..c7779c77dfe4cf5a672a265b6e796c7153590170 100644
--- a/src/tail.c
+++ b/src/tail.c
@@ -596,7 +596,7 @@ file_lines (char const *prettyname, int fd, struct stat const *sb,
goto free_buffer;
}
- pos = xlseek (fd, -bufsize, SEEK_CUR, prettyname);
+ pos = xlseek (fd, -(bufsize + bytes_read), SEEK_CUR, prettyname);
bytes_read = read (fd, buffer, bufsize);
if (bytes_read < 0)
{