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init: code cleanup

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illiliti 2021-05-10 14:35:34 +03:00
parent 654a787074
commit 1d8b2ca1e9
1 changed files with 41 additions and 29 deletions
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70
init
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@ -1,8 +1,8 @@
#!/bin/sh #!/bin/sh
# #
# tiny init # Tiny init
# #
# false positive # https://www.shellcheck.net/wiki/SC2154
# shellcheck disable=2154 # shellcheck disable=2154
print() print()
@ -13,8 +13,10 @@ print()
panic() panic()
{ {
print "${1:-unexpected error occurred}" \ print "${1:-unexpected error occurred}" \
"\033[1;31m!!\033[m" >&2; sh "\033[1;31m!!\033[m"
}
sh
} >&2
resolve_device() resolve_device()
{ {
@ -28,12 +30,16 @@ resolve_device()
*) return 0 ;; *) return 0 ;;
esac esac
# prevent race condition # Race condition may occur if device manager is not yet initialized device.
while [ ! -b "$device" ]; do sleep 1 # To fix this, we simply waiting until device is available. If device
[ "$((count += 1))" = "${rootdelay:=30}" ] && { # didn't appear in specified time, we panic.
while [ ! -b "$device" ]; do
if [ "$((count += 1))" = "${rootdelay:=30}" ]; then
panic "failed to lookup partition" panic "failed to lookup partition"
break break
} else
sleep 1
fi
done || : done || :
} }
@ -41,8 +47,9 @@ run_hook()
{ {
type="$1" type="$1"
# run hooks if any # Run hooks if any exist.
# false positive #
# https://www.shellcheck.net/wiki/SC1090
# shellcheck disable=1090 # shellcheck disable=1090
for hook in $hooks; do for hook in $hooks; do
[ -f "/usr/share/tinyramfs/hooks/${hook}/${hook}.${type}" ] || continue [ -f "/usr/share/tinyramfs/hooks/${hook}/${hook}.${type}" ] || continue
@ -52,7 +59,7 @@ run_hook()
prepare_environment() prepare_environment()
{ {
# false positive # https://www.shellcheck.net/wiki/SC1091
# shellcheck disable=1091 # shellcheck disable=1091
. /etc/tinyramfs/config . /etc/tinyramfs/config
@ -92,13 +99,11 @@ mount_root()
resolve_device "$root" resolve_device "$root"
set -- \ # https://www.shellcheck.net/wiki/SC2086
"${rorw:--o ro}${root_opts:+,$root_opts}" \ # shellcheck disable=2086
"${root_type:+-t $root_type}" "$device" "/mnt/root" mount \
${rorw:--o ro}${root_opts:+,$root_opts} ${root_type:+-t $root_type} \
# word splitting is safe by design -- "$device" /mnt/root || panic "failed to mount root"
# shellcheck disable=2068
mount $@ || panic "failed to mount root"
} }
boot_system() boot_system()
@ -109,19 +114,26 @@ boot_system()
mount -o move "$dir" "/mnt/root/${dir}" mount -o move "$dir" "/mnt/root/${dir}"
done done
set -- "/mnt/root" "${init:-/sbin/init}" "$init_args" # POSIX 'exec' has no '-c' flag to execute command with empty environment.
# Using 'env -i' instead to prevent leaking exported variables.
# POSIX exec has no -c flag to execute command with empty environment #
# use 'env -i' to prevent leaking exported variables # Some implementations of 'switch_root' doesn't conform to POSIX utility
# word splitting is safe by design # guidelines and doesn't support '--'. This means that we can't guarantee
# shellcheck disable=2068 # safety of init_args.
exec env -i TERM=linux PATH=/bin:/sbin:/usr/bin:/usr/sbin \ # shellcheck disable=2086
switch_root $@ || panic "failed to boot system" exec \
env -i TERM=linux PATH=/bin:/sbin:/usr/bin:/usr/sbin \
switch_root /mnt/root "${init-/sbin/init}" $init_args ||
panic "failed to boot system"
} }
# enable exit on error and disable globbing # Exit if command fails and disable globbing.
# trap EXIT signal set -ef
set -ef; trap panic EXIT
# Run emergency shell if init unexpectedly exiting due to error.
trap panic EXIT
# TODO display fancy colored status info
prepare_environment prepare_environment
parse_cmdline parse_cmdline