[PATCH 11/11] libfile: copy_file: explicitly truncate to final size

[Sascha Hauer <s.hauer@pengutronix.de>]

When possible truncate the destination file to the final size
explicitly. This allows for example ramfs to put the resulting
file contiguously into memory.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 lib/libfile.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/lib/libfile.c b/lib/libfile.c
index 9de938b2d3..863b6833a5 100644
--- a/lib/libfile.c
+++ b/lib/libfile.c
@@ -353,10 +353,6 @@ int copy_file(const char *src, const char *dst, int verbose)
 		goto out;
 	}
 
-	/* Set O_TRUNC only if file exist and is a regular file */
-	if (!s && S_ISREG(dststat.st_mode))
-		mode |= O_TRUNC;
-
 	dstfd = open(dst, mode);
 	if (dstfd < 0) {
 		printf("could not open %s: %s\n", dst, errno_str());
@@ -364,12 +360,22 @@ int copy_file(const char *src, const char *dst, int verbose)
 		goto out;
 	}
 
+	ret = ftruncate(dstfd, 0);
+	if (ret)
+		goto out;
+
 	ret = stat(src, &srcstat);
 	if (ret)
 		goto out;
 
-	if (srcstat.st_size != FILESIZE_MAX)
+	if (srcstat.st_size != FILESIZE_MAX) {
 		discard_range(dstfd, srcstat.st_size, 0);
+		if (S_ISREG(dststat.st_mode)) {
+			ret = ftruncate(dstfd, srcstat.st_size);
+			if (ret)
+				goto out;
+		}
+	}
 
 	if (verbose)
 		init_progression_bar(srcstat.st_size);
-- 
2.27.0


_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox