linux-kernel - Re: [PATCH v2 1/2] scripts: Add a recorduidiv program

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Date:	Wed, 2 Dec 2015 10:23:39 +0000
From:	Russell King - ARM Linux <linux@....linux.org.uk>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	Michal Marek <mmarek@...e.cz>,
	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
	Måns Rullgård <mans@...sr.com>,
	Arnd Bergmann <arnd@...db.de>, linux-kbuild@...r.kernel.org,
	linux-arm-msm@...r.kernel.org, Nicolas Pitre <nico@...xnic.net>,
	Stephen Boyd <sboyd@...eaurora.org>,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 1/2] scripts: Add a recorduidiv program

On Tue, Dec 01, 2015 at 06:16:43PM +0000, Russell King - ARM Linux wrote:
> On Tue, Dec 01, 2015 at 12:22:12PM -0500, Steven Rostedt wrote:
> > I guess another solution is to do a copy instead of modifying in place
> > if it detects the multiple hard link?
> 
> That would be the "transparent" solution.  If you think it's worth
> persuing, I'll have a go at fixing recordmcount to do that.

Well, copying the file is easy - I've tested this and the linker
appears happy with the result:

 scripts/recordmcount.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index 698768bdc581..91705ef30402 100644
--- a/scripts/recordmcount.c
+++ b/scripts/recordmcount.c
@@ -211,6 +211,20 @@ 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;
 }
 

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