bpftool: Address minor issues in bash completion

This commit contains a series of clean-ups and fixes for bpftool's bash
completion file:

- Make sure all local variables are declared as such.
- Make sure variables are initialised before being read.
- Update ELF section ("maps" -> ".maps") for looking up map names in
  object files.
- Fix call to _init_completion.
- Move definition for MAP_TYPE and PROG_TYPE higher up in the scope to
  avoid defining them multiple times, reuse MAP_TYPE where relevant.
- Simplify completion for "duration" keyword in "bpftool prog profile".
- Fix completion for "bpftool struct_ops register" and "bpftool link
  (pin|detach)" where we would repeatedly suggest file names instead of
  suggesting just one name.
- Fix completion for "bpftool iter pin ... map MAP" to account for the
  "map" keyword.
- Add missing "detach" suggestion for "bpftool link".

Signed-off-by: Quentin Monnet <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

tools/bpf/bpftool/bash-completion/bpftool

@@ -106,19 +106,19 @@ _bpftool_get_link_ids()
 
 _bpftool_get_obj_map_names()
 {
- local obj
+ local obj maps
 
  obj=$1
 
- maps=$(objdump -j maps -t $obj 2>/dev/null | \
- command awk '/g . maps/ {print $NF}')
+ maps=$(objdump -j .maps -t $obj 2>/dev/null | \
+ command awk '/g . .maps/ {print $NF}')
 
  COMPREPLY+=( $( compgen -W "$maps" -- "$cur" ) )
 }
 
 _bpftool_get_obj_map_idxs()
 {
- local obj
+ local obj nmaps
 
  obj=$1
 
@@ -136,7 +136,7 @@ _sysfs_get_netdevs()
 # Retrieve type of the map that we are operating on.
 _bpftool_map_guess_map_type()
 {
- local keyword ref
+ local keyword idx ref=""
  for (( idx=3; idx < ${#words[@]}-1; idx++ )); do
  case "${words[$((idx-2))]}" in
  lookup|update)
@@ -255,8 +255,9 @@ _bpftool_map_update_get_name()
 
 _bpftool()
 {
- local cur prev words objword json=0
- _init_completion || return
+ local cur prev words cword comp_args
+ local json=0
+ _init_completion -- "$@" || return
 
  # Deal with options
  if [[ ${words[cword]} == -* ]]; then
@@ -293,7 +294,7 @@ _bpftool()
  esac
 
  # Remove all options so completions don't have to deal with them.
- local i
+ local i pprev
  for (( i=1; i < ${#words[@]}; )); do
  if [[ ${words[i]::1} == - ]] &&
  [[ ${words[i]} != "-B" ]] && [[ ${words[i]} != "--base-btf" ]]; then
@@ -307,7 +308,7 @@ _bpftool()
  prev=${words[cword - 1]}
  pprev=${words[cword - 2]}
 
- local object=${words[1]} command=${words[2]}
+ local object=${words[1]}
 
  if [[ -z $object || $cword -eq 1 ]]; then
  case $cur in
@@ -324,8 +325,12 @@ _bpftool()
  esac
  fi
 
+ local command=${words[2]}
  [[ $command == help ]] && return 0
 
+ local MAP_TYPE='id pinned name'
+ local PROG_TYPE='id pinned tag name'
+
  # Completion depends on object and command in use
  case $object in
  prog)
@@ -346,8 +351,6 @@ _bpftool()
  ;;
  esac
 
- local PROG_TYPE='id pinned tag name'
- local MAP_TYPE='id pinned name'
  local METRIC_TYPE='cycles instructions l1d_loads llc_misses \
  itlb_misses dtlb_misses'
  case $command in
@@ -457,7 +460,7 @@ _bpftool()
  obj=${words[3]}
 
  if [[ ${words[-4]} == "map" ]]; then
- COMPREPLY=( $( compgen -W "id pinned" -- "$cur" ) )
+ COMPREPLY=( $( compgen -W "$MAP_TYPE" -- "$cur" ) )
  return 0
  fi
  if [[ ${words[-3]} == "map" ]]; then
@@ -541,20 +544,9 @@ _bpftool()
  COMPREPLY=( $( compgen -W "$METRIC_TYPE duration" -- "$cur" ) )
  return 0
  ;;
- 6)
- case $prev in
- duration)
- return 0
- ;;
- *)
- COMPREPLY=( $( compgen -W "$METRIC_TYPE" -- "$cur" ) )
- return 0
- ;;
- esac
- return 0
- ;;
  *)
- COMPREPLY=( $( compgen -W "$METRIC_TYPE" -- "$cur" ) )
+ [[ $prev == duration ]] && return 0
+ _bpftool_once_attr "$METRIC_TYPE"
  return 0
  ;;
  esac
@@ -612,7 +604,7 @@ _bpftool()
  return 0
  ;;
  register)
- _filedir
+ [[ $prev == $command ]] && _filedir
  return 0
  ;;
  *)
@@ -638,9 +630,12 @@ _bpftool()
  pinned)
  _filedir
  ;;
- *)
+ map)
  _bpftool_one_of_list $MAP_TYPE
  ;;
+ *)
+ _bpftool_once_attr 'map'
+ ;;
  esac
  return 0
  ;;
@@ -652,7 +647,6 @@ _bpftool()
  esac
  ;;
  map)
- local MAP_TYPE='id pinned name'
  case $command in
  show|list|dump|peek|pop|dequeue|freeze)
  case $prev in
@@ -793,13 +787,11 @@ _bpftool()
  # map, depending on the type of the map to update.
  case "$(_bpftool_map_guess_map_type)" in
  array_of_maps|hash_of_maps)
- local MAP_TYPE='id pinned name'
  COMPREPLY+=( $( compgen -W "$MAP_TYPE" \
  -- "$cur" ) )
  return 0
  ;;
  prog_array)
- local PROG_TYPE='id pinned tag name'
  COMPREPLY+=( $( compgen -W "$PROG_TYPE" \
  -- "$cur" ) )
  return 0
@@ -821,7 +813,7 @@ _bpftool()
  esac
 
  _bpftool_once_attr 'key'
- local UPDATE_FLAGS='any exist noexist'
+ local UPDATE_FLAGS='any exist noexist' idx
  for (( idx=3; idx < ${#words[@]}-1; idx++ )); do
  if [[ ${words[idx]} == 'value' ]]; then
  # 'value' is present, but is not the last
@@ -893,7 +885,6 @@ _bpftool()
  esac
  ;;
  btf)
- local PROG_TYPE='id pinned tag name'
  local MAP_TYPE='id pinned name'
  case $command in
  dump)
@@ -1033,7 +1024,6 @@ _bpftool()
  local BPFTOOL_CGROUP_ATTACH_TYPES="$(bpftool feature list_builtins attach_types 2>/dev/null | \
  grep '^cgroup_')"
  local ATTACH_FLAGS='multi override'
- local PROG_TYPE='id pinned tag name'
  # Check for $prev = $command first
  if [ $prev = $command ]; then
  _filedir
@@ -1086,7 +1076,6 @@ _bpftool()
  esac
  ;;
  net)
- local PROG_TYPE='id pinned tag name'
  local ATTACH_TYPES='xdp xdpgeneric xdpdrv xdpoffload'
  case $command in
  show|list)
@@ -1193,14 +1182,14 @@ _bpftool()
  pin|detach)
  if [[ $prev == "$command" ]]; then
  COMPREPLY=( $( compgen -W "$LINK_TYPE" -- "$cur" ) )
- else
+ elif [[ $pprev == "$command" ]]; then
  _filedir
  fi
  return 0
  ;;
  *)
  [[ $prev == $object ]] && \
- COMPREPLY=( $( compgen -W 'help pin show list' -- "$cur" ) )
+ COMPREPLY=( $( compgen -W 'help pin detach show list' -- "$cur" ) )
  ;;
  esac
  ;;