[src/trunk]: src/usr.bin/cmp add a flag to avoid mmap...

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/cce423b5970a
branches:  trunk
changeset: 348615:cce423b5970a
user:      christos <christos%NetBSD.org@localhost>
date:      Sun Oct 30 19:13:36 2016 +0000

description:
add a flag to avoid mmap...

diffstat:

 usr.bin/cmp/cmp.1 |  15 ++++++++++++---
 usr.bin/cmp/cmp.c |  13 ++++++++-----
 2 files changed, 20 insertions(+), 8 deletions(-)

diffs (91 lines):

diff -r 484dd0231786 -r cce423b5970a usr.bin/cmp/cmp.1
--- a/usr.bin/cmp/cmp.1 Sun Oct 30 16:17:16 2016 +0000
+++ b/usr.bin/cmp/cmp.1 Sun Oct 30 19:13:36 2016 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: cmp.1,v 1.9 2003/08/07 11:13:21 agc Exp $
+.\"    $NetBSD: cmp.1,v 1.10 2016/10/30 19:13:36 christos Exp $
 .\"
 .\" Copyright (c) 1987, 1990, 1993
 .\"    The Regents of the University of California.  All rights reserved.
@@ -32,7 +32,7 @@
 .\"
 .\"     @(#)cmp.1      8.1 (Berkeley) 6/6/93
 .\"
-.Dd June 6, 1993
+.Dd October 30, 2016
 .Dt CMP 1
 .Os
 .Sh NAME
@@ -40,7 +40,7 @@
 .Nd compare two files
 .Sh SYNOPSIS
 .Nm
-.Op Fl l | Fl s
+.Op Fl c | Fl l | Fl s
 .Ar file1 file2
 .Op Ar skip1 Op Ar skip2
 .Sh DESCRIPTION
@@ -55,6 +55,15 @@
 .Pp
 The following options are available:
 .Bl -tag -width flag
+.It Fl c
+Do the compare using
+.Xr getc 3
+rather than
+.Xr mmap 2 .
+Combined with the
+.Fl l
+flag, this can be helpful in locating an I/O error in the underlying
+device.
 .It Fl l
 Print the byte number (decimal) and the differing
 byte values (octal) for each difference.
diff -r 484dd0231786 -r cce423b5970a usr.bin/cmp/cmp.c
--- a/usr.bin/cmp/cmp.c Sun Oct 30 16:17:16 2016 +0000
+++ b/usr.bin/cmp/cmp.c Sun Oct 30 19:13:36 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cmp.c,v 1.18 2011/08/29 14:14:11 joerg Exp $   */
+/*     $NetBSD: cmp.c,v 1.19 2016/10/30 19:13:36 christos Exp $        */
 
 /*
  * Copyright (c) 1987, 1990, 1993, 1994
@@ -39,7 +39,7 @@
 #if 0
 static char sccsid[] = "@(#)cmp.c      8.3 (Berkeley) 4/2/94";
 #else
-__RCSID("$NetBSD: cmp.c,v 1.18 2011/08/29 14:14:11 joerg Exp $");
+__RCSID("$NetBSD: cmp.c,v 1.19 2016/10/30 19:13:36 christos Exp $");
 #endif
 #endif /* not lint */
 
@@ -71,8 +71,12 @@
 
        setlocale(LC_ALL, "");
 
-       while ((ch = getopt(argc, argv, "ls")) != -1)
+       special = 0;
+       while ((ch = getopt(argc, argv, "cls")) != -1)
                switch (ch) {
+               case 'c':
+                       special = 1;    /* careful!  Don't use mmap() */
+                       break;
                case 'l':               /* print all differences */
                        lflag = 1;
                        break;
@@ -93,7 +97,6 @@
                usage();
 
        /* Backward compatibility -- handle "-" meaning stdin. */
-       special = 0;
        if (strcmp(file1 = argv[0], "-") == 0) {
                special = 1;
                fd1 = 0;
@@ -159,6 +162,6 @@
 {
 
        (void)fprintf(stderr,
-           "usage: cmp [-l | -s] file1 file2 [skip1 [skip2]]\n");
+           "usage: cmp [-c | -l | -s] file1 file2 [skip1 [skip2]]\n");
        exit(ERR_EXIT);
 }