tail: fix fallout from tail -c optimization

3 files changed, 17 insertions, 21 deletions

diff --git a/coreutils/tail.c b/coreutils/tail.c
index 35b25a416..2f997a9f6 100644
--- a/coreutils/tail.c
+++ b/coreutils/tail.c
@@ -163,8 +163,6 @@ int tail_main(int argc, char **argv)
         fmt = header_fmt + 1;   /* Skip header leading newline on first output. */
         i = 0;
         do {
-                off_t current;
-
                 if (nfiles > header_threshhold) {
                         tail_xprint_header(fmt, argv[i]);
                         fmt = header_fmt;
@@ -173,19 +171,17 @@ int tail_main(int argc, char **argv)
                 /* Optimizing count-bytes case if the file is seekable.
                  * Beware of backing up too far.
                  * Also we exclude files with size 0 (because of /proc/xxx) */
-                current = lseek(fds[i], 0, SEEK_END);
-                if (current > 0) {
-                        if (!from_top) {
+                if (COUNT_BYTES && !from_top) {
+                        off_t current = lseek(fds[i], 0, SEEK_END);
+                        if (current > 0) {
                                 if (count == 0)
                                         continue; /* showing zero lines is easy :) */
-                                if (COUNT_BYTES) {
-                                        current -= count;
-                                        if (current < 0)
-                                                current = 0;
-                                        xlseek(fds[i], current, SEEK_SET);
-                                        bb_copyfd_size(fds[i], STDOUT_FILENO, count);
-                                        continue;
-                                }
+                                current -= count;
+                                if (current < 0)
+                                        current = 0;
+                                xlseek(fds[i], current, SEEK_SET);
+                                bb_copyfd_size(fds[i], STDOUT_FILENO, count);
+                                continue;
                         }
                 }
 
diff --git a/testsuite/tail/tail-n-works b/testsuite/tail/tail-n-works
index 27a905f88..e5b260caf 100644
--- a/testsuite/tail/tail-n-works
+++ b/testsuite/tail/tail-n-works
@@ -1,4 +1,4 @@
-[ -n "$d" ] || d=..
-tail -n 2 "$d/README" > logfile.gnu
-busybox tail -n 2 "$d/README" > logfile.bb
-cmp logfile.gnu logfile.bb
+echo -ne "abc\ndef\n123\n" >input
+echo -ne "def\n123\n" >logfile.ok
+busybox tail -n 2 input > logfile.bb
+cmp logfile.ok logfile.bb
diff --git a/testsuite/tail/tail-works b/testsuite/tail/tail-works
index 27a905f88..64e6d88ab 100644
--- a/testsuite/tail/tail-works
+++ b/testsuite/tail/tail-works
@@ -1,4 +1,4 @@
-[ -n "$d" ] || d=..
-tail -n 2 "$d/README" > logfile.gnu
-busybox tail -n 2 "$d/README" > logfile.bb
-cmp logfile.gnu logfile.bb
+echo -ne "abc\ndef\n123\n" >input
+echo -ne "def\n123\n" >logfile.ok
+busybox tail -2 input > logfile.bb
+cmp logfile.ok logfile.bb