block: Fix backing paths for filenames with colons

path_combine() naturally tries to preserve a protocol prefix. However,
it recognizes such a prefix by scanning for the first colon; which is
different from what path_has_protocol() does: There only is a protocol
prefix if there is a colon before the first slash.

A protocol prefix that is not recognized by path_has_protocol() is none,
and should thus not be taken as one.

Case in point, before this patch:
$ ./qemu-img create -f qcow2 -b backing.qcow2 ./top:image.qcow2
qemu-img: ./top:image.qcow2: Could not open './top:backing.qcow2':
    No such file or directory

Afterwards:
$ ./qemu-img create -f qcow2 -b backing.qcow2 ./top:image.qcow2
qemu-img: ./top:image.qcow2: Could not open './backing.qcow2':
    No such file or directory

Reported-by: yangyang <yangyang@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20170522195217.12991-2-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Max Reitz 2017-05-22 21:52:15 +02:00
parent bcb07dba92
commit 0d54a6fed3

15
block.c
View File

@ -163,11 +163,16 @@ void path_combine(char *dest, int dest_size,
if (path_is_absolute(filename)) {
pstrcpy(dest, dest_size, filename);
} else {
p = strchr(base_path, ':');
if (p)
p++;
else
p = base_path;
const char *protocol_stripped = NULL;
if (path_has_protocol(base_path)) {
protocol_stripped = strchr(base_path, ':');
if (protocol_stripped) {
protocol_stripped++;
}
}
p = protocol_stripped ?: base_path;
p1 = strrchr(base_path, '/');
#ifdef _WIN32
{