Hi,
$ dd of=sparsefile seek=4096 bs=1M count=0
$ tar -c --sparse --format=gnu -f sparsefile.gtar sparsefile
$ tar -x -f sparsefile.gtar -O sparsefile | cat >/dev/null
tar: sparsefile: Cannot seek to 4294967296: Invalid argument
tar: Error exit delayed from previous errors
$ tar -c --sparse --format=posix -f sparsefile.ptar sparsefile
$ tar -t -v -f sparsefile.ptar
-rw-rw-r-- eswierk/eswierk 4294967296 2006-03-14 13:22:30 sparsefile
tar: Unexpected EOF in archive
tar: Error is not recoverable: exiting now
$ tar -x -f sparsefile.ptar -O sparsefile | cat >/dev/null
tar: Unexpected EOF in archive
tar: Unexpected EOF in archive
tar: Error is not recoverable: exiting now
If you repeat the above procedure with a smaller sparse file (1 MB
instead of 4096 MB), all the tar operations succeed.
Attached patch fix the first problem with gnu format.
--- tar-1.15.1/src/sparse.c.extractHugeSparse 2006-03-21 14:22:05.000000000 -0500
+++ tar-1.15.1/src/sparse.c 2006-03-21 14:23:27.000000000 -0500
@@ -47,7 +47,7 @@
{
int fd; /* File descriptor */
bool seekable; /* Is fd seekable? */
- size_t offset; /* Current offset in fd if seekable==false.
+ off_t offset; /* Current offset in fd if seekable==false.
Otherwise unused */
size_t dumped_size; /* Number of bytes actually written
to the archive */
@@ -59,7 +59,7 @@
/* Dump zeros to file->fd until offset is reached. It is used instead of
lseek if the output file is not seekable */
-static long
+static off_t
dump_zeros (struct tar_sparse_file *file, off_t offset)
{
char buf[BLOCKSIZE];
@@ -76,8 +76,11 @@
size_t size = offset - file->offset;
size_t wrbytes;
- if (size > sizeof buf)
- size = sizeof buf;
+ if ( (offset - file->offset) > sizeof buf)
+ size = sizeof buf;
+ else
+ size = offset - file->offset;
+
wrbytes = write (file->fd, buf, size);
if (wrbytes <= 0)
{
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