From 90f446f9b04ab820a99b9408e68c01dc6b57056c Mon Sep 17 00:00:00 2001
From: rpm-build <rpm-build>
Date: Mon, 28 Jul 2014 08:10:10 +0200
Subject: [PATCH 2/9] vfat-like FS & sparse (still downstream)

Fix extracting sparse files to a file system like vfat, when
ftruncate may fail to grow the size of a file.  Still downstram,
(do we need this now? ftruncate & vfat works is now OK).

Resolves: #179507

Upstream bugreport:
http://lists.gnu.org/archive/html/bug-tar/2006-02/msg00000.html

---
 src/system.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/system.c b/src/system.c
index 9e273bc..e62edd8 100644
--- a/src/system.c
+++ b/src/system.c
@@ -244,8 +244,25 @@ sys_compare_links (struct stat *link_data, struct stat *stat_data)
 int
 sys_truncate (int fd)
 {
+  struct stat st;
   off_t pos = lseek (fd, (off_t) 0, SEEK_CUR);
-  return pos < 0 ? -1 : ftruncate (fd, pos);
+
+  if ( pos < 0) 
+    return -1;
+
+  if ( ftruncate(fd, pos) && errno == EPERM ) {
+    /* wrapper around ftruncate:
+     * ftruncate may fail to grow the size of a file with some OS and filesystem
+     * combinations. Linux and vfat/fat is one example. If this is the case do
+     * a write to grow the file to the desired length.
+     */
+    if( (fstat( fd, &st ) == -1) || 
+        (st.st_size >= pos)  ||
+        (lseek( fd, pos - 1, SEEK_SET) == (off_t)-1) ||
+        (write( fd, "\0", 1) == -1) )
+	return -1;
+  }
+  return 0;
 }
 
 /* Return nonzero if NAME is the name of a regular file, or if the file
-- 
1.8.3.1