Re: [Libguestfs] [PATCH] Correctly detect the size of a block device over SSH

When fetching a storage volume over SSH, we were detecting its size with a simple 'stat -c %s'. While this works fine for files, it won't return the correct size of a block device. This patch uses the output of 'blockdev --getsize64' for block devices, and stat as before for regular files. Fixes RHBZ#620698 --- lib/Sys/VirtV2V/Transfer/SSH.pm | 16 +++++++++++++++- 1 files changed, 15 insertions(+), 1 deletions(-) diff --git a/lib/Sys/VirtV2V/Transfer/SSH.pm b/lib/Sys/VirtV2V/Transfer/SSH.pm index 66ec294..5f54f0e 100644 --- a/lib/Sys/VirtV2V/Transfer/SSH.pm +++ b/lib/Sys/VirtV2V/Transfer/SSH.pm @@ -138,7 +138,21 @@ sub _connect push(@command, 'ssh'); push(@command, '-l', $username) if (defined($username)); push(@command, $host); - push(@command, "stat -c %s $path; cat $path"); + + # Return the size of the remote path on the first line, followed by its + # contents. + # The bit arithmetic with the output of stat is a translation into shell + # of the S_ISBLK macro. If the remote device is a block device, stat + # will simply return the size of the block device inode. In this case, + # we use the output of blockdev --getsize64 instead. + push(@command, + "dev=$path; ". + 'if [[ $(((0x$(stat -L -c %f $dev)&0170000)>>12)) == 6 ]]; then '. + 'blockdev --getsize64 $dev; '. + 'else '. + 'stat -L -c %s $dev; '. + 'fi; '. + 'cat $dev'); # Close the ends of the pipes we don't need close($stdin_write);