[Bug-tar] tar fails to extract large sparse archive member

[Peter Vrabec]

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-extractHugeSparse.patch
Description: Text Data