linux-kernel - [PATCH 3.12 073/116] scripts: recordmcount: break hardlinks

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Message-Id: <40c0155d68140a36d52cc7f94cce5fa1f289509f.1457082108.git.jslaby@suse.cz>
Date:	Fri,  4 Mar 2016 10:01:58 +0100
From:	Jiri Slaby <jslaby@...e.cz>
To:	stable@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org,
	Russell King <rmk+kernel@....linux.org.uk>,
	Steven Rostedt <rostedt@...dmis.org>,
	Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 3.12 073/116] scripts: recordmcount: break hardlinks

From: Russell King <rmk+kernel@....linux.org.uk>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit dd39a26538e37f6c6131e829a4a510787e43c783 upstream.

recordmcount edits the file in-place, which can cause problems when
using ccache in hardlink mode.  Arrange for recordmcount to break a
hardlinked object.

Link: http://lkml.kernel.org/r/E1a7MVT-0000et-62@rmk-PC.arm.linux.org.uk

Signed-off-by: Russell King <rmk+kernel@....linux.org.uk>
Signed-off-by: Steven Rostedt <rostedt@...dmis.org>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
---
 scripts/recordmcount.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index 9c22317778eb..ee625e3a56ba 100644
--- a/scripts/recordmcount.c
+++ b/scripts/recordmcount.c
@@ -189,6 +189,20 @@ static void *mmap_file(char const *fname)
 		addr = umalloc(sb.st_size);
 		uread(fd_map, addr, sb.st_size);
 	}
+	if (sb.st_nlink != 1) {
+		/* file is hard-linked, break the hard link */
+		close(fd_map);
+		if (unlink(fname) < 0) {
+			perror(fname);
+			fail_file();
+		}
+		fd_map = open(fname, O_RDWR | O_CREAT, sb.st_mode);
+		if (fd_map < 0) {
+			perror(fname);
+			fail_file();
+		}
+		uwrite(fd_map, addr, sb.st_size);
+	}
 	return addr;
 }
 
-- 
2.7.2