scripts: recordmcount: break hardlinks

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@arm.linux.org.uk>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index 650ecc83d7d72f89b012ec2f1ee41ef895aa398f..26f0cd2c8e9a92e0f79f84639da81295f07bffd8 100644 (file)
--- a/scripts/recordmcount.c
+++ b/scripts/recordmcount.c
@@ -194,6 +194,20 @@ 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;
 }