From 849d265d53a721b9bfb8bd5a5e204c026436316d Mon Sep 17 00:00:00 2001
From: Jaakko Heinonen <jh@FreeBSD.org>
Date: Sun, 9 Jun 2013 08:06:26 +0000
Subject: [PATCH] Print file names without stdio buffering to avoid mixing
 buffered and unbuffered ouput.

PR:		bin/176886
Reviewed by:	mjg
---
 usr.bin/tail/extern.h  |  1 +
 usr.bin/tail/forward.c |  4 ++--
 usr.bin/tail/misc.c    | 14 ++++++++++++++
 usr.bin/tail/tail.c    |  4 +---
 4 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/usr.bin/tail/extern.h b/usr.bin/tail/extern.h
index 16a3e19a4406..dfc63d07424e 100644
--- a/usr.bin/tail/extern.h
+++ b/usr.bin/tail/extern.h
@@ -67,5 +67,6 @@ void ierr(const char *);
 void oerr(void);
 int mapprint(struct mapinfo *, off_t, off_t);
 int maparound(struct mapinfo *, off_t);
+void printfn(const char *, int);
 
 extern int Fflag, fflag, qflag, rflag, rval, no_files;
diff --git a/usr.bin/tail/forward.c b/usr.bin/tail/forward.c
index 3c605bf37bca..5eaae9828647 100644
--- a/usr.bin/tail/forward.c
+++ b/usr.bin/tail/forward.c
@@ -243,7 +243,7 @@ show(file_info_t *file)
 	while ((ch = getc(file->fp)) != EOF) {
 		if (last != file && no_files > 1) {
 			if (!qflag)
-				(void)printf("\n==> %s <==\n", file->file_name);
+				printfn(file->file_name, 1);
 			last = file;
 		}
 		if (putchar(ch) == EOF)
@@ -320,7 +320,7 @@ follow(file_info_t *files, enum STYLE style, off_t off)
 			active = 1;
 			n++;
 			if (no_files > 1 && !qflag)
-				(void)printf("\n==> %s <==\n", file->file_name);
+				printfn(file->file_name, 1);
 			forward(file->fp, file->file_name, style, off, &file->st);
 			if (Fflag && fileno(file->fp) != STDIN_FILENO)
 				n++;
diff --git a/usr.bin/tail/misc.c b/usr.bin/tail/misc.c
index 3b21e4e3f34d..69443257f9c7 100644
--- a/usr.bin/tail/misc.c
+++ b/usr.bin/tail/misc.c
@@ -113,3 +113,17 @@ maparound(struct mapinfo *mip, off_t offset)
 
 	return (0);
 }
+
+/*
+ * Print the file name without stdio buffering.
+ */
+void
+printfn(const char *fn, int print_nl)
+{
+
+	if (print_nl)
+		WR("\n", 1);
+	WR("==> ", 4);
+	WR(fn, strlen(fn));
+	WR(" <==\n", 5);
+}
diff --git a/usr.bin/tail/tail.c b/usr.bin/tail/tail.c
index a53a56809838..e5566cb0a703 100644
--- a/usr.bin/tail/tail.c
+++ b/usr.bin/tail/tail.c
@@ -203,10 +203,8 @@ main(int argc, char *argv[])
 				continue;
 			}
 			if (argc > 1 && !qflag) {
-				(void)printf("%s==> %s <==\n",
-				    first ? "" : "\n", fn);
+				printfn(fn, !first);
 				first = 0;
-				(void)fflush(stdout);
 			}
 
 			if (rflag)