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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index 9c22317778e..ee625e3a56b 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;
 }