130 lines
5.3 KiB
Bash
130 lines
5.3 KiB
Bash
# shellcheck shell=bash
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#
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# Copyright (C) 2017 Canonical Ltd
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License version 3 as
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# published by the Free Software Foundation.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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# _complete_from_snap performs the tab completion request by calling the
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# appropriate 'snap run --command=complete' with serialized args, and
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# deserializes the response into the usual tab completion result.
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#
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# How snap command completion works is:
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# 1. snapd's complete.sh is sourced into the user's shell environment
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# 2. user performs '<command> <tab>'. If '<command>' is a snap command,
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# proceed to step '3', otherwise perform normal bash completion
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# 3. run 'snap run --command=complete ...', converting bash completion
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# environment into serialized command line arguments
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# 4. 'snap run --command=complete ...' exec()s 'etelpmoc.sh' within the snap's
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# runtime environment and confinement
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# 5. 'etelpmoc.sh' takes the serialized command line arguments from step '3'
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# and puts them back into the bash completion environment variables
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# 6. 'etelpmoc.sh' sources the snap's 'completer' script, performs the bash
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# completion and serializes the resulting completion environment variables
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# by printing to stdout the results in a format that snapd's complete.sh
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# will understand, then exits
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# 7. control returns to snapd's 'complete.sh' and it deserializes the output
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# from 'etelpmoc.sh', validates the results and puts the validated results
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# into the bash completion environment variables
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# 8. bash displays the results to the user
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type -t _complete_from_snap > /dev/null ||
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_complete_from_snap() {
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{
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# De-serialize the output of 'snap run --command=complete ...' into the format
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# bash expects:
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read -r -a opts
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# opts is expected to be a series of compopt options
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if [[ ${#opts[@]} -gt 0 ]]; then
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if [[ "${opts[0]}" == "cannot" ]]; then
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# older snap-execs sent errors over stdout :-(
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return 1
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fi
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for i in "${opts[@]}"; do
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if ! [[ "$i" =~ ^[a-z]+$ ]]; then
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# only lowercase alpha characters allowed
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return 2
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fi
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done
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fi
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read -r bounced
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case "$bounced" in
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""|"alias"|"export"|"job"|"variable")
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# OK
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;;
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*)
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# unrecognised bounce
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return 2
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;;
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esac
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read -r sep
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if [ -n "$sep" ]; then
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# non-blank separator? madness!
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return 2
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fi
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local oldIFS="$IFS"
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if [ ! "$bounced" ]; then
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local IFS=$'\n'
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# Ignore any suspicious results that are uncommon in filenames and that
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# might be used to trick the user. A whitelist approach would be better
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# but is impractical with UTF-8 and common characters like quotes.
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COMPREPLY=( $( command grep -v '[[:cntrl:];&?*{}]' ) )
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IFS="$oldIFS"
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fi
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if [[ ${#opts[@]} -gt 0 ]]; then
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# shellcheck disable=SC2046
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# (we *want* word splitting to happen here)
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compopt $(printf " -o %s" "${opts[@]}")
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fi
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if [ "$bounced" ]; then
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# We validated '$bounced' above and '${COMP_WORDS[$COMP_CWORD]}' is
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# coming from the user's session, not the snap so skip input
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# validation: we aren't trying to protect the user from themselves.
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COMPREPLY+=(compgen -A "$bounced" -- "${COMP_WORDS[$COMP_CWORD]}")
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fi
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} < <(
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snap run --command=complete "$1" "$COMP_TYPE" "$COMP_KEY" "$COMP_POINT" "$COMP_CWORD" "$COMP_WORDBREAKS" "$COMP_LINE" "${COMP_WORDS[@]}" 2>/dev/null || return 1
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)
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}
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# this file can be sourced directly as e.g. /usr/lib/snapd/complete.sh, or via
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# a symlink from /var/lib/snapd/desktop/bash-completion/completions/. In the first case we
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# want to load the default loader; in the second, the specific one.
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#
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if [[ "${BASH_SOURCE[0]}" =~ ^(/var/lib/snapd/desktop|/usr/share)/bash-completion/completions/ ]]; then
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complete -F _complete_from_snap "$1"
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else
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# _complete_from_snap_maybe calls _complete_from_snap if the command is in
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# bin/snap, and otherwise does bash-completion's _completion_loader (which is
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# what -D would've done before).
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type -t _complete_from_snap_maybe > /dev/null ||
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_complete_from_snap_maybe() {
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local etel=snap/core/current/usr/lib/snapd/etelpmoc.sh
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# catch /snap/bin and /var/lib/snapd/snap/bin
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if [[ "$(command -v "$1")" =~ ^(/var/lib/snapd)?/snap/bin/ && ( -e "/var/lib/snapd/$etel" || -e "/$etel" ) ]]; then
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complete -F _complete_from_snap "$1"
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return 124
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fi
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# fallback to the old -D
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_completion_loader "$1"
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}
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complete -D -F _complete_from_snap_maybe
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fi
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