[PATCH] treewide: replace `which` with `command -v`

Paul Spooren mail at aparcar.org
Fri Aug 7 23:24:23 EDT 2020


On 07.08.20 16:48, Rosen Penev wrote:
> On Fri, Aug 7, 2020 at 5:42 PM Paul Spooren <mail at aparcar.org> wrote:
>>
>> On 07.08.20 14:18, Rosen Penev wrote:
>>> On Fri, Aug 7, 2020 at 3:57 PM Paul Spooren <mail at aparcar.org> wrote:
>>>> Fix shellcheck SC2230
>>>>> which is non-standard. Use builtin 'command -v' instead.
>>>> Once applied to everything concerning OpenWrt we can disable the busybox
>>>> feature `which` and save 3.8kB.
>>> which and command -v seem to not be the same. See
>>> https://github.com/openwrt/openwrt/commit/8242c6de29951fbb549355770cd685ffe3ac9c54
>> Afaik ldir uses a Mac which may has a different build in implementation
>> of `command`.
>>
>> Testing it locally on a Linux machine they behave very much the same.
>>
>> user at dawn:~/src/openwrt/openwrt$ command -v git
>> /usr/bin/git
>> user at dawn:~/src/openwrt/openwrt$ which git
>> /usr/bin/git
>> user at dawn:~/src/openwrt/openwrt$ command -v git-nope
>> user at dawn:~/src/openwrt/openwrt$ echo $?
>> 1
>> user at dawn:~/src/openwrt/openwrt$ which git-nope
>> user at dawn:~/src/openwrt/openwrt$ echo $?
>> 1
>>
>> I'd image the *command* `command` doesn't exist on a Mac and it would
>> actually execute the *command* `git` there, which obviously pollutes the
>> output.
> command is a shell builtin. macOS used bash and now zsh. I doubt
> that's the problem.

All right, I found the issue. The problem is the following commit:

https://github.com/openwrt/openwrt/commit/56f813674a912490df327304033bf667b285930a

It replaces the function without migrating the 2>/dev/null. It's 
therefore neither the fault of MacOS nor command.

I therefore assume my proposed patch is fine.

>> Seems like a problem of Mac and not the bash/sh included `command`.
>> Thinking about that, it seems fairly dangerous: If you'd run `command -v
>> nuke_harddrive > /dev/null` it would actually run whatever command silently.
>>
>> There is a wrapper called `./scripts/md5sum` which calls `md5`, the Mac
>> tool to get a MD5 checksum.
>>
>> I guess we could create a wrapper like ./scripts/command which contains
>> the following line:
>>
>> which $2 # skipping the -v arg of command
>>
>> Ultimately it's about freeing up busybox-which, which is independent of
>> any Mac ideas. For that rootfs.mk and ipkg-build could be left untouched.
>>
>>>> Signed-off-by: Paul Spooren <mail at aparcar.org>
>>>> ---
>>>>    include/rootfs.mk                                    |  6 +++---
>>>>    package/base-files/files/lib/upgrade/stage2          |  2 +-
>>>>    .../kernel/broadcom-wl/files/lib/wifi/broadcom.sh    |  2 +-
>>>>    scripts/ipkg-build                                   | 12 ++++++------
>>>>    4 files changed, 11 insertions(+), 11 deletions(-)
>>>>
>>>> diff --git a/include/rootfs.mk b/include/rootfs.mk
>>>> index b6775c7e15..18ada3cd43 100644
>>>> --- a/include/rootfs.mk
>>>> +++ b/include/rootfs.mk
>>>> @@ -69,7 +69,7 @@ define prepare_rootfs
>>>>           @( \
>>>>                   cd $(1); \
>>>>                   for script in ./usr/lib/opkg/info/*.postinst; do \
>>>> -                       IPKG_INSTROOT=$(1) $$(which bash) $$script; \
>>>> +                       IPKG_INSTROOT=$(1) $$(command -v bash) $$script; \
>>>>                           ret=$$?; \
>>>>                           if [ $$ret -ne 0 ]; then \
>>>>                                   echo "postinst script $$script has failed with exit code $$ret" >&2; \
>>>> @@ -79,10 +79,10 @@ define prepare_rootfs
>>>>                   for script in ./etc/init.d/*; do \
>>>>                           grep '#!/bin/sh /etc/rc.common' $$script >/dev/null || continue; \
>>>>                           if ! echo " $(3) " | grep -q " $$(basename $$script) "; then \
>>>> -                               IPKG_INSTROOT=$(1) $$(which bash) ./etc/rc.common $$script enable; \
>>>> +                               IPKG_INSTROOT=$(1) $$(command -v bash) ./etc/rc.common $$script enable; \
>>>>                                   echo "Enabling" $$(basename $$script); \
>>>>                           else \
>>>> -                               IPKG_INSTROOT=$(1) $$(which bash) ./etc/rc.common $$script disable; \
>>>> +                               IPKG_INSTROOT=$(1) $$(command -v bash) ./etc/rc.common $$script disable; \
>>>>                                   echo "Disabling" $$(basename $$script); \
>>>>                           fi; \
>>>>                   done || true \
>>>> diff --git a/package/base-files/files/lib/upgrade/stage2 b/package/base-files/files/lib/upgrade/stage2
>>>> index dbb33e8958..a4fef42134 100755
>>>> --- a/package/base-files/files/lib/upgrade/stage2
>>>> +++ b/package/base-files/files/lib/upgrade/stage2
>>>> @@ -45,7 +45,7 @@ switch_to_ramfs() {
>>>>                   snapshot snapshot_tool                                  \
>>>>                   $RAMFS_COPY_BIN
>>>>           do
>>>> -               local file="$(which "$binary" 2>/dev/null)"
>>>> +               local file="$(command -v "$binary" 2>/dev/null)"
>>>>                   [ -n "$file" ] && install_bin "$file"
>>>>           done
>>>>           install_file /etc/resolv.conf /lib/*.sh /lib/functions/*.sh /lib/upgrade/*.sh /lib/upgrade/do_stage2 /usr/share/libubox/jshn.sh $RAMFS_COPY_DATA
>>>> diff --git a/package/kernel/broadcom-wl/files/lib/wifi/broadcom.sh b/package/kernel/broadcom-wl/files/lib/wifi/broadcom.sh
>>>> index 33447341b2..352c365f27 100644
>>>> --- a/package/kernel/broadcom-wl/files/lib/wifi/broadcom.sh
>>>> +++ b/package/kernel/broadcom-wl/files/lib/wifi/broadcom.sh
>>>> @@ -223,7 +223,7 @@ enable_broadcom() {
>>>>           }
>>>>
>>>>           local _c=0
>>>> -       local nas="$(which nas)"
>>>> +       local nas="$(command -v nas)"
>>>>           local if_pre_up if_up nas_cmd
>>>>           local vif vif_pre_up vif_post_up vif_do_up vif_txpower
>>>>           local bssmax=$(wlc ifname "$device" bssmax)
>>>> diff --git a/scripts/ipkg-build b/scripts/ipkg-build
>>>> index 21127f3391..6e027bc546 100755
>>>> --- a/scripts/ipkg-build
>>>> +++ b/scripts/ipkg-build
>>>> @@ -10,10 +10,10 @@
>>>>    set -e
>>>>
>>>>    version=1.0
>>>> -FIND="$(which find)"
>>>> -FIND="${FIND:-$(which gfind)}"
>>>> -TAR="${TAR:-$(which tar)}"
>>>> -GZIP="$(which gzip)"
>>>> +FIND="$(command -v find)"
>>>> +FIND="${FIND:-$(command -v gfind)}"
>>>> +TAR="${TAR:-$(command -v tar)}"
>>>> +GZIP="$(command -v gzip)"
>>>>
>>>>    # try to use fixed source epoch
>>>>    if [ -n "$SOURCE_DATE_EPOCH" ]; then
>>>> @@ -21,10 +21,10 @@ if [ -n "$SOURCE_DATE_EPOCH" ]; then
>>>>
>>>>    # look up date of last commit
>>>>    elif [ -d "$TOPDIR/.git" ]; then
>>>> -       GIT="$(which git)"
>>>> +       GIT="$(command -v git)"
>>>>           TIMESTAMP=$(cd $TOPDIR; $GIT log -1 -s --format=%ci)
>>>>    elif [ -d "$TOPDIR/.svn" ]; then
>>>> -       SVN="$(which svn)"
>>>> +       SVN="$(command -v svn)"
>>>>           TIMESTAMP=$($SVN info "$TOPDIR" | sed -n "s/^Last Changed Date: \(.*\)/\1/p")
>>>>    else
>>>>           TIMESTAMP=$(date)
>>>> --
>>>> 2.25.1
>>>>
>>>>
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>>>> openwrt-devel at lists.openwrt.org
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