From: Karel Zak <kzak@redhat.com>
Date: Mon, 2 Sep 2019 09:53:10 +0000 (+0200)
Subject: colcrt: make seek to \n more robust
X-Git-Tag: v2.35-rc1~247
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d3565072076f9414e315750862621e83a2be5afb;p=thirdparty%2Futil-linux.git

colcrt: make seek to \n more robust

Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/text-utils/colcrt.c b/text-utils/colcrt.c
index 798f5bd7b8..113e3d0b69 100644
--- a/text-utils/colcrt.c
+++ b/text-utils/colcrt.c
@@ -151,7 +151,7 @@ static int rubchars(struct colcrt_control *ctl, int col, int n)
 static void colcrt(struct colcrt_control *ctl)
 {
 	int col;
-	wint_t c;
+	wint_t c = 0;
 	long old_pos;
 
 	ctl->print_nl = 1;
@@ -163,16 +163,18 @@ static void colcrt(struct colcrt_control *ctl)
 			output_lines(ctl, col);
 			errno = 0;
 			old_pos = ftell(ctl->f);
-			while ((c = getwc(ctl->f)) != L'\n') {
-				long new_pos = ftell(ctl->f);
-				if (old_pos == new_pos)
-					fseek(ctl->f, 1, SEEK_CUR);
-				else
-					old_pos = new_pos;
-				if (errno == 0 && c == WEOF)
+
+			while (getwc(ctl->f) != L'\n') {
+				long new_pos;
+
+				if (ferror(ctl->f) || feof(ctl->f))
 					return;
-				else
-					errno = 0;
+				new_pos = ftell(ctl->f);
+				if (old_pos == new_pos) {
+					if (fseek(ctl->f, 1, SEEK_CUR) < 1)
+						return;
+				} else
+					old_pos = new_pos;
 			}
 			col = -1;
 			continue;