- prefer using `which` over hard coded paths
- it is redundant to check that the bin pointed to the return of
`which` exists and is executable, `which` already gives us
assurance of that if it returns true!
- the redirection of output (`2>/dev/null`) seems to be
unnecessary from my testing.
the instances relatnig to fdisk and losetup in functions/defaults.sh have
been left as they are since they get executed by `lb config` which can run
without sudo elevation unlike `lb build` and in that case `which` would
fail to find these binaries resulting in error.
this also fixes a bug showing an error for missing debootstrap - this tool
requires sudo privileges to run and thus is not found via a none elevated
which search.
Gbp-Dch: Short
Closes: #952927
Recent versions of Linux, parted or some other bit of software cause
partition devices, like /dev/loop0p1 to be created when running parted
mkpart. However, these devices are not cleaned up when running
losetup -d to remove /dev/loop0 later, so they linger around and confuse
mkfs (which refuses to make a filesystem, thinking there are partitions):
mkfs.fat 4.1 (2017-01-24)
mkfs.vfat: Partitions or virtual mappings on device '/dev/loop0', not making filesystem (use -I to override)
To prevent this behaviour, pass --partscan to losetup when adding a new
partition, to clean up any lingering partitions. It seems losetup does not
accept --partscan when deleting a loop device, to clean up at that point, but
since binary_hdd mounts the partition last, there should not be any lingering
partition devices after live-build is done.
The --partscan option is available since util-linux 2.21 (released in 2012), so
it should be fairly safe to pass it unconditionally.