From 1fd6e0f27a1b79aefcbc7bda5f618c8c59842dce Mon Sep 17 00:00:00 2001
From: op <op@openbsd.org>
Date: Sun, 26 Jun 2022 10:57:36 +0000
Subject: [PATCH] grep: add --null flag

makes grep print an ASCII NUL byte after the file name to make the
output unambiguous even in the presence of file names with funny
characters.

A previous iteration of this diff was improved by benno@ and tedu@ and
discussed also with sthen@ and deraadt@.  deraadt@ also improved the
manpage changes in this version of the diff.

OK deraadt@
---
 usr.bin/grep/grep.1 | 14 ++++++++++++--
 usr.bin/grep/grep.c |  8 +++++++-
 usr.bin/grep/grep.h |  4 ++--
 usr.bin/grep/util.c | 21 +++++++++++++--------
 4 files changed, 34 insertions(+), 13 deletions(-)

diff --git a/usr.bin/grep/grep.1 b/usr.bin/grep/grep.1
index 5cc228df222..8701df169f6 100644
--- a/usr.bin/grep/grep.1
+++ b/usr.bin/grep/grep.1
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: grep.1,v 1.50 2019/12/03 08:48:49 kn Exp $
+.\"	$OpenBSD: grep.1,v 1.51 2022/06/26 10:57:36 op Exp $
 .\" Copyright (c) 1980, 1990, 1993
 .\"	The Regents of the University of California.  All rights reserved.
 .\"
@@ -28,7 +28,7 @@
 .\"
 .\"	@(#)grep.1	8.3 (Berkeley) 4/18/94
 .\"
-.Dd $Mdocdate: December 3 2019 $
+.Dd $Mdocdate: June 26 2022 $
 .Dt GREP 1
 .Os
 .Sh NAME
@@ -49,6 +49,7 @@
 .Op Fl -context Ns Op = Ns Ar num
 .Op Fl -label Ns = Ns Ar name
 .Op Fl -line-buffered
+.Op Fl -null
 .Op Ar pattern
 .Op Ar
 .Ek
@@ -297,6 +298,15 @@ instead of the filename before lines.
 Force output to be line buffered.
 By default, output is line buffered when standard output is a terminal
 and block buffered otherwise.
+.It Fl -null
+Output a zero byte instead of the character that normally follows a
+file name.
+This option makes the output unambiguous, even in the presence of file
+names containing unusual characters like newlines.
+This is similar to the
+.Ar -print0
+option in
+.Xr find 1 .
 .El
 .Sh EXIT STATUS
 The
diff --git a/usr.bin/grep/grep.c b/usr.bin/grep/grep.c
index f41b5e20ca6..181af7f6ada 100644
--- a/usr.bin/grep/grep.c
+++ b/usr.bin/grep/grep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: grep.c,v 1.65 2020/07/23 20:19:27 martijn Exp $	*/
+/*	$OpenBSD: grep.c,v 1.66 2022/06/26 10:57:36 op Exp $	*/
 
 /*-
  * Copyright (c) 1999 James Howard and Dag-Erling Coïdan Smørgrav
@@ -80,6 +80,7 @@ int	 vflag;		/* -v: only show non-matching lines */
 int	 wflag;		/* -w: pattern must start and end on word boundaries */
 int	 xflag;		/* -x: pattern must match entire line */
 int	 lbflag;	/* --line-buffered */
+int	 nullflag;	/* --null */
 const char *labelname;	/* --label=name */
 
 int binbehave = BIN_FILE_BIN;
@@ -89,6 +90,7 @@ enum {
 	HELP_OPT,
 	MMAP_OPT,
 	LINEBUF_OPT,
+	NULL_OPT,
 	LABEL_OPT,
 };
 
@@ -134,6 +136,7 @@ static const struct option long_options[] =
 	{"mmap",		no_argument,		NULL, MMAP_OPT},
 	{"label",		required_argument,	NULL, LABEL_OPT},
 	{"line-buffered",	no_argument,		NULL, LINEBUF_OPT},
+	{"null",		no_argument,		NULL, NULL_OPT},
 	{"after-context",	required_argument,	NULL, 'A'},
 	{"before-context",	required_argument,	NULL, 'B'},
 	{"context",		optional_argument,	NULL, 'C'},
@@ -436,6 +439,9 @@ main(int argc, char *argv[])
 		case LINEBUF_OPT:
 			lbflag = 1;
 			break;
+		case NULL_OPT:
+			nullflag = 1;
+			break;
 		case HELP_OPT:
 		default:
 			usage();
diff --git a/usr.bin/grep/grep.h b/usr.bin/grep/grep.h
index 731bbcc35af..07c8069d5aa 100644
--- a/usr.bin/grep/grep.h
+++ b/usr.bin/grep/grep.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: grep.h,v 1.28 2021/03/10 21:55:22 millert Exp $	*/
+/*	$OpenBSD: grep.h,v 1.29 2022/06/26 10:57:36 op Exp $	*/
 
 /*-
  * Copyright (c) 1999 James Howard and Dag-Erling Coïdan Smørgrav
@@ -68,7 +68,7 @@ extern int	 cflags, eflags;
 extern int	 Aflag, Bflag, Eflag, Fflag, Hflag, Lflag,
 		 Rflag, Zflag,
 		 bflag, cflag, hflag, iflag, lflag, mflag, nflag, oflag, qflag,
-		 sflag, vflag, wflag, xflag;
+		 sflag, vflag, wflag, xflag, nullflag;
 extern int	 binbehave;
 extern const char *labelname;
 
diff --git a/usr.bin/grep/util.c b/usr.bin/grep/util.c
index 33b10946590..d1840b96513 100644
--- a/usr.bin/grep/util.c
+++ b/usr.bin/grep/util.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: util.c,v 1.65 2022/05/30 16:07:28 dv Exp $	*/
+/*	$OpenBSD: util.c,v 1.66 2022/06/26 10:57:36 op Exp $	*/
 
 /*-
  * Copyright (c) 1999 James Howard and Dag-Erling Coïdan Smørgrav
@@ -172,13 +172,13 @@ procfile(char *fn)
 
 	if (cflag) {
 		if (!hflag)
-			printf("%s:", ln.file);
+			printf("%s%c", ln.file, nullflag ? '\0' : ':');
 		printf("%llu%s\n", c, overflow ? "+" : "");
 	}
 	if (lflag && c != 0)
-		printf("%s\n", fn);
+		printf("%s%c", fn, nullflag ? '\0' : '\n');
 	if (Lflag && c == 0)
-		printf("%s\n", fn);
+		printf("%s%c", fn, nullflag ? '\0' : '\n');
 	if (c && !cflag && !lflag && !Lflag &&
 	    binbehave == BIN_FILE_BIN && nottext && !qflag)
 		printf("Binary file %s matches\n", fn);
@@ -653,27 +653,32 @@ grep_revstr(unsigned char *str, int len)
 void
 printline(str_t *line, int sep, regmatch_t *pmatch)
 {
-	int n;
+	int n, printsep;
 
 	n = 0;
+	printsep = !nullflag;
 	if (!hflag) {
 		fputs(line->file, stdout);
+		if (nullflag)
+			putchar(0);
 		++n;
 	}
 	if (nflag) {
-		if (n)
+		if (n && printsep)
 			putchar(sep);
 		printf("%lld", line->line_no);
+		printsep = 1;
 		++n;
 	}
 	if (bflag) {
-		if (n)
+		if (n && printsep)
 			putchar(sep);
 		printf("%lld", (long long)line->off +
 		    (pmatch ? pmatch->rm_so : 0));
+		printsep = 1;
 		++n;
 	}
-	if (n)
+	if (n && printsep)
 		putchar(sep);
 	if (pmatch)
 		fwrite(line->dat + pmatch->rm_so,
-- 
2.20.1