mirror_zfs/contrib/dracut/90zfs/zfs-generator.sh.in
Graham Christensen dda702fd16
bash scripts: use /usr/bin/env for bash shebangs
Not all systems / distros have a `/bin/bash`, and these scripts are
more difficult to run at development time.

For example, my system is NixOS which doesn't have a /bin/bash. This
is not a problem for NixOS building ZFS as a package: the build
environment automatically replaces these shebangs with corrected
paths.

The problem is much more annoying at development time: either the
scripts don't run, or I correct them for my local machine and deal with
a perpetually dirty work tree.

Before committing this patch I confirmed there are existing scripts
which use `/usr/bin/env` to locate bash, so I am thinking this is a
safe transformation.

There are a handful of other shebangs in this repository which don't
work on my system. This patch is useful on its own specifically for
`commitcheck.sh`, otherwise I can't validate my commits before
submission.

Here are the remaining shebangs which NixOS systems won't have:

       1274 #!/bin/ksh -p
         91 #!/bin/ksh
         89 #! /bin/ksh -p
          2 #!/bin/sed -f
          1 #!/usr/bin/perl -w
          1 #!/usr/bin/ksh
          1 #!/bin/nawk -f

plus this which will create an invalid shebang in
`tests/zfs-tests/tests/functional/mv_files/mv_files_common.kshlib`:

        echo "#!/bin/ksh" > $TEST_BASE_DIR/exitsZero.ksh

I chose to leave those alone for now, and gauge the interest in this
much smaller patch first.

The fixes for these are easy enough by simply using `/usr/bin/env ksh`:

         91 #!/bin/ksh
          1 #!/usr/bin/ksh

The fix for the other set is much trickier. Quoting the GNU coreutils
manual:

    Most operating systems (e.g. GNU/Linux, BSDs) treat all text after
    the first space as a single argument. When using env in a script it
    is thus not possible to specify multiple arguments.

and not all `env`'s support arguments.

Mine (GNU Coreutils 8.31) does, though this feature is new since
April 2018, GNU Coreutils 8.30:
https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=668306ed86c8c79b0af0db8b9c882654ebb66db2

and worse, requires the -S argument:

    -S, --split-string=S  process and split S into separate arguments;
                          used to pass multiple arguments on shebang
                          lines

Example:

    $ seq 1 2 | $(nix-build '<nixpkgs>' -A coreutils)/bin/env "sort -nr"
    /nix/[...]-coreutils-8.31/bin/env: ‘sort -nr’: No such file or directory
    /nix/[...]-coreutils-8.31/bin/env: use -[v]S to pass options in shebang lines

    $ seq 1 2 | $(nix-build '<nixpkgs>' -A coreutils)/bin/env "-S sort -nr"
    2
    1

GNU Coreutils says FreeBSD's `env` does, though I wonder if FreeBSD's
would be unhappy with the `-S`:
https://www.gnu.org/software/coreutils/manual/html_node/env-invocation.html#env-invocation

BusyBox v1.30.1 does not, and does not have a `-S`-like option:

    $ seq 1 2 | $(nix-build '<nixpkgs>' -A busybox)/bin/env "sort -nr"
    env: can't execute 'sort -nr': No such file or directory

Toybox 0.8.1 also does not, and also does not have a `-S` option:

    $ seq 1 2 | $(nix-build '<nixpkgs>' -A toybox)/bin/env "sort -nr"
    env: exec sort -nr: No such file or directory

---

At any rate, if this patch merges and the remaining ~1,500 are updated,
the much larger patch should probably include a checkstyle-like test
asserting all new shebangs use `/usr/bin/env`. I also don't mind
dealing with NixOS weirdness if the project would prefer that.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Graham Christensen <graham@grahamc.com>
Closes #9893
2020-02-10 13:13:46 -08:00

61 lines
2.0 KiB
Bash
Executable File

#!/usr/bin/env bash
echo "zfs-generator: starting" >> /dev/kmsg
GENERATOR_DIR="$1"
[ -n "$GENERATOR_DIR" ] || {
echo "zfs-generator: no generator directory specified, exiting" >> /dev/kmsg
exit 1
}
[ -f /lib/dracut-lib.sh ] && dracutlib=/lib/dracut-lib.sh
[ -f /usr/lib/dracut/modules.d/99base/dracut-lib.sh ] && dracutlib=/usr/lib/dracut/modules.d/99base/dracut-lib.sh
type getarg >/dev/null 2>&1 || {
echo "zfs-generator: loading Dracut library from $dracutlib" >> /dev/kmsg
. "$dracutlib"
}
[ -z "$root" ] && root=$(getarg root=)
[ -z "$rootfstype" ] && rootfstype=$(getarg rootfstype=)
[ -z "$rootflags" ] && rootflags=$(getarg rootflags=)
# If root is not ZFS= or zfs: or rootfstype is not zfs
# then we are not supposed to handle it.
[ "${root##zfs:}" = "${root}" -a "${root##ZFS=}" = "${root}" -a "$rootfstype" != "zfs" ] && exit 0
rootfstype=zfs
if echo "${rootflags}" | grep -Eq '^zfsutil$|^zfsutil,|,zfsutil$|,zfsutil,' ; then
true
elif test -n "${rootflags}" ; then
rootflags="zfsutil,${rootflags}"
else
rootflags=zfsutil
fi
echo "zfs-generator: writing extension for sysroot.mount to $GENERATOR_DIR"/sysroot.mount.d/zfs-enhancement.conf >> /dev/kmsg
[ -d "$GENERATOR_DIR" ] || mkdir "$GENERATOR_DIR"
[ -d "$GENERATOR_DIR"/sysroot.mount.d ] || mkdir "$GENERATOR_DIR"/sysroot.mount.d
{
echo "[Unit]"
echo "Before=initrd-root-fs.target"
echo "After=zfs-import.target"
echo "[Mount]"
if [ "${root}" = "zfs:AUTO" ] ; then
echo "PassEnvironment=BOOTFS"
echo 'What=${BOOTFS}'
else
root="${root##zfs:}"
root="${root##ZFS=}"
echo "What=${root}"
fi
echo "Type=${rootfstype}"
echo "Options=${rootflags}"
} > "$GENERATOR_DIR"/sysroot.mount.d/zfs-enhancement.conf
[ -d "$GENERATOR_DIR"/initrd-root-fs.target.requires ] || mkdir -p "$GENERATOR_DIR"/initrd-root-fs.target.requires
ln -s ../sysroot.mount "$GENERATOR_DIR"/initrd-root-fs.target.requires/sysroot.mount
echo "zfs-generator: finished" >> /dev/kmsg