Re: [Buildroot] [RFC PATCH 1/3] make: support: use `command -v' instead of `which'

["Yann E. MORIN" <yann.morin.1998@free.fr>]

Petr, All,

On 2021-10-12 00:00 +0200, Petr Vorel spake thusly:
> `which' has been discontinued after 2.21 release in 2015 due this (git
> repository is empty [1]) and version shipped in Debian produces warning
> [2]:
> 
> /usr/bin/which: this version of `which' is deprecated; use `command -v' in scripts instead.

In the meantime, this is supposed to have been overrdien by the
technical committee:

    https://lwn.net/ml/debian-ctte/handler.994275.D994275.163536015027825.ackdone@bugs.debian.org/

Excerpt:

 --8<---
 1. The debianutils package must continue to provide the which(1) program
    until a compatible utility is available in a package that is at least
    transitively essential in Debian 12.

    For the Debian 12 release, we expect which(1) to be in either an
    Essential package or a transitively Essential package (that is, a
    package that is depended on by an Essential package).

 2. The which(1) program must not print any deprecation warnings.
 --8<---

As such, the situation is a calmer for now and is less urgent, and we
can address it for after 2021.11 (given that Debian 11 was released only
3 months ago, we have a bit of time ahead of us before Debian 12 finally
ships! ;-] )

Regards,
Yann E. MORIN.

> `command is POSIX [3] and supported on all common shells (bash, zsh,
> dash, busybox sh, mksh).
> 
> NOTE: originally merged as ca6a2907c2, but it had to be reverted due
> errors [4] (originally reported [5]). Problems were:
> 
> 1) Main problem was that make sometimes expected `command' as a
>    binary/script and run it with execve() (or any other exec*()
>    wrapper), instead of running it through a shell via system() [4]:
> 
>     $ make defconfig
>     [...]
>     $ make help
>     make[1]: command: Command not found
>     [...]
> 
>    Fixed by not relying to $(shell command -v ...) but shell with:
>    $(shell $(SHELL) -c "command -v ...").
> 
> 2) `command -v' handles only first parameter (unlike `which') [4].
>    Hopefully fixed with quoting variables. Quoting variables is also
>    needed, because both `command -v' without args and `type -p' exit 0.
> 
> Patch tested on both bash and dash as /bin/sh on various distros with
> having different make versions, including these previously affected
> (4.2.1, 4.0, 3.81).
> 
> [1] https://git.savannah.gnu.org/cgit/which.git
> [2] https://salsa.debian.org/debian/debianutils/-/commit/3a8dd10b4502f7bae8fc6973c13ce23fc9da7efb
> [3] https://pubs.opengroup.org/onlinepubs/9699919799/utilities/command.html
> [4] https://lore.kernel.org/buildroot/20210930200402.GO1504958@scaer/
> [5] https://lore.kernel.org/buildroot/YVTIghzHs82uFBIe@pevik/T/#m95c17eb8374e4e3dd6eee700d397aa12cca0739e
> 
> Signed-off-by: Petr Vorel <petr.vorel@gmail.com>
> ---
>  Makefile                                      | 22 +++++++++----------
>  package/Makefile.in                           |  8 +++----
>  support/dependencies/check-host-bison-flex.mk |  4 ++--
>  support/dependencies/check-host-cmake.sh      |  2 +-
>  support/dependencies/check-host-gzip.sh       |  2 +-
>  support/dependencies/check-host-lzip.sh       |  4 ++--
>  support/dependencies/check-host-python3.sh    |  2 +-
>  support/dependencies/check-host-tar.sh        |  4 ++--
>  support/dependencies/check-host-xzcat.sh      |  4 ++--
>  support/dependencies/dependencies.sh          | 16 +++++++-------
>  .../pkg-toolchain-external.mk                 |  2 +-
>  11 files changed, 35 insertions(+), 35 deletions(-)
> 
> diff --git a/Makefile b/Makefile
> index c960b53a6d..2317655272 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -284,12 +284,12 @@ HOSTAS := as
>  endif
>  ifndef HOSTCC
>  HOSTCC := gcc
> -HOSTCC := $(shell which $(HOSTCC) || type -p $(HOSTCC) || echo gcc)
> +HOSTCC := $(shell $(SHELL) -c "command -v '$(HOSTCC)' || type -p '$(HOSTCC)' || echo gcc")
>  endif
>  HOSTCC_NOCCACHE := $(HOSTCC)
>  ifndef HOSTCXX
>  HOSTCXX := g++
> -HOSTCXX := $(shell which $(HOSTCXX) || type -p $(HOSTCXX) || echo g++)
> +HOSTCXX := $(shell $(SHELL) -c "command -v '$(HOSTCXX)' || type -p '$(HOSTCXX)' || echo g++")
>  endif
>  HOSTCXX_NOCCACHE := $(HOSTCXX)
>  ifndef HOSTCPP
> @@ -310,15 +310,15 @@ endif
>  ifndef HOSTRANLIB
>  HOSTRANLIB := ranlib
>  endif
> -HOSTAR := $(shell which $(HOSTAR) || type -p $(HOSTAR) || echo ar)
> -HOSTAS := $(shell which $(HOSTAS) || type -p $(HOSTAS) || echo as)
> -HOSTCPP := $(shell which $(HOSTCPP) || type -p $(HOSTCPP) || echo cpp)
> -HOSTLD := $(shell which $(HOSTLD) || type -p $(HOSTLD) || echo ld)
> -HOSTLN := $(shell which $(HOSTLN) || type -p $(HOSTLN) || echo ln)
> -HOSTNM := $(shell which $(HOSTNM) || type -p $(HOSTNM) || echo nm)
> -HOSTOBJCOPY := $(shell which $(HOSTOBJCOPY) || type -p $(HOSTOBJCOPY) || echo objcopy)
> -HOSTRANLIB := $(shell which $(HOSTRANLIB) || type -p $(HOSTRANLIB) || echo ranlib)
> -SED := $(shell which sed || type -p sed) -i -e
> +HOSTAR := $(shell '$(SHELL)' -c "command -v '$(HOSTAR)' || type -p '$(HOSTAR)' || echo ar")
> +HOSTAS := $(shell '$(SHELL)' -c "command -v '$(HOSTAS)' || type -p '$(HOSTAS)' || echo as")
> +HOSTCPP := $(shell '$(SHELL)' -c "command -v '$(HOSTCPP)' || type -p '$(HOSTCPP)' || echo cpp")
> +HOSTLD := $(shell '$(SHELL)' -c "command -v '$(HOSTLD)' || type -p '$(HOSTLD)' || echo ld")
> +HOSTLN := $(shell '$(SHELL)' -c "command -v '$(HOSTLN)' || type -p '$(HOSTLN)' || echo ln")
> +HOSTNM := $(shell '$(SHELL)' -c "command -v '$(HOSTNM)' || type -p '$(HOSTNM)' || echo nm")
> +HOSTOBJCOPY := $(shell '$(SHELL)' -c "command -v '$(HOSTOBJCOPY)' || type -p '$(HOSTOBJCOPY)' || echo objcopy")
> +HOSTRANLIB := $(shell '$(SHELL)' -c "command -v '$(HOSTRANLIB)' || type -p '$(HOSTRANLIB)' || echo ranlib")
> +SED := $(shell $(SHELL) -c "command -v sed || type -p sed") -i -e
>  
>  export HOSTAR HOSTAS HOSTCC HOSTCXX HOSTLD
>  export HOSTCC_NOCCACHE HOSTCXX_NOCCACHE
> diff --git a/package/Makefile.in b/package/Makefile.in
> index 86db62ba5b..2ba4d8b381 100644
> --- a/package/Makefile.in
> +++ b/package/Makefile.in
> @@ -4,7 +4,7 @@ endif
>  ifndef HOSTMAKE
>  HOSTMAKE = $(MAKE)
>  endif
> -HOSTMAKE := $(shell which $(HOSTMAKE) || type -p $(HOSTMAKE) || echo make)
> +HOSTMAKE := $(shell $(SHELL) -c "command -v '$(HOSTMAKE)' || type -p '$(HOSTMAKE)' || echo make")
>  
>  # If BR2_JLEVEL is 0, scale the maximum concurrency with the number of
>  # CPUs. An additional job is used in order to keep processors busy
> @@ -222,8 +222,8 @@ else
>  TARGET_STRIP = /bin/true
>  STRIPCMD = $(TARGET_STRIP)
>  endif
> -INSTALL := $(shell which install || type -p install)
> -UNZIP := $(shell which unzip || type -p unzip) -q
> +INSTALL := $(shell $(SHELL) -c "command -v install || type -p install")
> +UNZIP := $(shell $(SHELL) -c "command -v unzip || type -p unzip") -q
>  
>  APPLY_PATCHES = PATH=$(HOST_DIR)/bin:$$PATH support/scripts/apply-patches.sh $(if $(QUIET),-s)
>  
> @@ -237,7 +237,7 @@ HOST_LDFLAGS  += -L$(HOST_DIR)/lib -Wl,-rpath,$(HOST_DIR)/lib
>  # the path to the system perl, before a host-perl built by Buildroot
>  # might get installed into $(HOST_DIR)/bin and therefore appears
>  # in our PATH. This system perl will be used as INTLTOOL_PERL.
> -export PERL=$(shell which perl)
> +export PERL=$(shell $(SHELL) -c "command -v perl")
>  
>  # host-intltool needs libxml-parser-perl, which Buildroot installs in
>  # $(HOST_DIR)/lib/perl, so we must make sure that the system perl
> diff --git a/support/dependencies/check-host-bison-flex.mk b/support/dependencies/check-host-bison-flex.mk
> index 14a232fd44..b6cec369f1 100644
> --- a/support/dependencies/check-host-bison-flex.mk
> +++ b/support/dependencies/check-host-bison-flex.mk
> @@ -5,10 +5,10 @@
>  # that runs on host, e.g. Kconfig. To build code for target use plain
>  # host-{bison,flex}.
>  
> -ifeq ($(shell which bison 2>/dev/null),)
> +ifeq ($(shell $(SHELL) -c "command -v bison 2>/dev/null"),)
>  BR2_BISON_HOST_DEPENDENCY = host-bison
>  endif
>  
> -ifeq ($(shell which flex 2>/dev/null),)
> +ifeq ($(shell $(SHELL) -c "command -v flex 2>/dev/null"),)
>  BR2_FLEX_HOST_DEPENDENCY = host-flex
>  endif
> diff --git a/support/dependencies/check-host-cmake.sh b/support/dependencies/check-host-cmake.sh
> index fadeae9f6b..f202d72a98 100755
> --- a/support/dependencies/check-host-cmake.sh
> +++ b/support/dependencies/check-host-cmake.sh
> @@ -11,7 +11,7 @@ shift
>  for candidate; do
>  
>      # Try to locate the candidate. Discard it if not located.
> -    cmake=`which "${candidate}" 2>/dev/null`
> +    cmake=`command -v "${candidate}" 2>/dev/null`
>      [ -n "${cmake}" ] || continue
>  
>      # Extract version X.Y from versions in the form X.Y or X.Y.Z
> diff --git a/support/dependencies/check-host-gzip.sh b/support/dependencies/check-host-gzip.sh
> index 5f344c5f9b..4dbce72676 100755
> --- a/support/dependencies/check-host-gzip.sh
> +++ b/support/dependencies/check-host-gzip.sh
> @@ -2,7 +2,7 @@
>  
>  candidate="$1" # ignored
>  
> -gzip="$(which gzip)"
> +gzip="$(command -v gzip)"
>  if [ ! -x "${gzip}" ]; then
>      # echo nothing: no suitable gzip found
>      exit 1
> diff --git a/support/dependencies/check-host-lzip.sh b/support/dependencies/check-host-lzip.sh
> index 4f8a2ba3de..5cdfb8252a 100755
> --- a/support/dependencies/check-host-lzip.sh
> +++ b/support/dependencies/check-host-lzip.sh
> @@ -2,9 +2,9 @@
>  
>  candidate="$1"
>  
> -lzip=`which $candidate 2>/dev/null`
> +lzip=`command -v "$candidate" 2>/dev/null`
>  if [ ! -x "$lzip" ]; then
> -	lzip=`which lzip 2>/dev/null`
> +	lzip=`command -v lzip 2>/dev/null`
>  	if [ ! -x "$lzip" ]; then
>  		# echo nothing: no suitable lzip found
>  		exit 1
> diff --git a/support/dependencies/check-host-python3.sh b/support/dependencies/check-host-python3.sh
> index 17cafd2883..ca504da6ac 100755
> --- a/support/dependencies/check-host-python3.sh
> +++ b/support/dependencies/check-host-python3.sh
> @@ -14,7 +14,7 @@ shift
>  # a more recent version.
>  
>  for candidate in "${@}" ; do
> -	python3=`which $candidate 2>/dev/null`
> +	python3=`command -v "$candidate" 2>/dev/null`
>  	if [ ! -x "$python3" ]; then
>  		continue
>  	fi
> diff --git a/support/dependencies/check-host-tar.sh b/support/dependencies/check-host-tar.sh
> index b7d607a47a..0f0f80038d 100755
> --- a/support/dependencies/check-host-tar.sh
> +++ b/support/dependencies/check-host-tar.sh
> @@ -2,9 +2,9 @@
>  
>  candidate="$1"
>  
> -tar=`which $candidate`
> +tar=`command -v "$candidate"`
>  if [ ! -x "$tar" ]; then
> -	tar=`which tar`
> +	tar=`command -v tar`
>  	if [ ! -x "$tar" ]; then
>  		# echo nothing: no suitable tar found
>  		exit 1
> diff --git a/support/dependencies/check-host-xzcat.sh b/support/dependencies/check-host-xzcat.sh
> index 10f1c4562a..a022c64faf 100755
> --- a/support/dependencies/check-host-xzcat.sh
> +++ b/support/dependencies/check-host-xzcat.sh
> @@ -2,9 +2,9 @@
>  
>  candidate="$1"
>  
> -xzcat=`which $candidate 2>/dev/null`
> +xzcat=`command -v "$candidate" 2>/dev/null`
>  if [ ! -x "$xzcat" ]; then
> -	xzcat=`which xzcat 2>/dev/null`
> +	xzcat=`command -v xzcat 2>/dev/null`
>  	if [ ! -x "$xzcat" ]; then
>  		# echo nothing: no suitable xzcat found
>  		exit 1
> diff --git a/support/dependencies/dependencies.sh b/support/dependencies/dependencies.sh
> index c604a9efcc..e720e9372e 100755
> --- a/support/dependencies/dependencies.sh
> +++ b/support/dependencies/dependencies.sh
> @@ -58,7 +58,7 @@ fi
>  check_prog_host()
>  {
>  	prog="$1"
> -	if ! which $prog > /dev/null ; then
> +	if ! command -v "$prog" > /dev/null ; then
>  		echo >&2
>  		echo "You must install '$prog' on your build machine" >&2
>  		exit 1
> @@ -75,7 +75,7 @@ check_prog_host "sed"
>  check_prog_host "/usr/bin/file"
>  
>  # Check make
> -MAKE=$(which make 2> /dev/null)
> +MAKE=$(command -v make 2> /dev/null)
>  if [ -z "$MAKE" ] ; then
>  	echo
>  	echo "You must install 'make' on your build machine";
> @@ -96,9 +96,9 @@ if [ $MAKE_MAJOR -lt 3 ] || [ $MAKE_MAJOR -eq 3 -a $MAKE_MINOR -lt 81 ] ; then
>  fi;
>  
>  # Check host gcc
> -COMPILER=$(which $HOSTCC_NOCCACHE 2> /dev/null)
> +COMPILER=$(command -v "$HOSTCC_NOCCACHE" 2> /dev/null)
>  if [ -z "$COMPILER" ] ; then
> -	COMPILER=$(which cc 2> /dev/null)
> +	COMPILER=$(command -v cc 2> /dev/null)
>  fi;
>  if [ -z "$COMPILER" ] ; then
>  	echo
> @@ -122,9 +122,9 @@ if [ $COMPILER_MAJOR -lt 4 -o $COMPILER_MAJOR -eq 4 -a $COMPILER_MINOR -lt 8 ] ;
>  fi;
>  
>  # check for host CXX
> -CXXCOMPILER=$(which $HOSTCXX_NOCCACHE 2> /dev/null)
> +CXXCOMPILER=$(command -v "$HOSTCXX_NOCCACHE" 2> /dev/null)
>  if [ -z "$CXXCOMPILER" ] ; then
> -	CXXCOMPILER=$(which c++ 2> /dev/null)
> +	CXXCOMPILER=$(command -v c++ 2> /dev/null)
>  fi
>  
>  if [ -z "$CXXCOMPILER" ] ; then
> @@ -164,7 +164,7 @@ fi
>  # Check that a few mandatory programs are installed
>  missing_progs="no"
>  for prog in perl tar wget cpio unzip rsync bc ${DL_TOOLS} ; do
> -	if ! which $prog > /dev/null ; then
> +	if ! command -v "$prog" > /dev/null ; then
>  		echo "You must install '$prog' on your build machine";
>  		missing_progs="yes"
>  		if test $prog = "svn" ; then
> @@ -198,7 +198,7 @@ if [ "${PATCH_MAJOR}" -lt 2 ] || [ "${PATCH_MAJOR}" -eq 2 -a "${PATCH_MINOR}" -l
>  fi
>  
>  if grep ^BR2_NEEDS_HOST_UTF8_LOCALE=y $BR2_CONFIG > /dev/null; then
> -	if ! which locale > /dev/null ; then
> +	if ! command -v locale > /dev/null ; then
>  		echo
>  		echo "You need locale support on your build machine to build a toolchain supporting locales"
>  		exit 1 ;
> diff --git a/toolchain/toolchain-external/pkg-toolchain-external.mk b/toolchain/toolchain-external/pkg-toolchain-external.mk
> index 68d7a3fe21..2d9d9a5d49 100644
> --- a/toolchain/toolchain-external/pkg-toolchain-external.mk
> +++ b/toolchain/toolchain-external/pkg-toolchain-external.mk
> @@ -74,7 +74,7 @@ endif
>  ifeq ($(TOOLCHAIN_EXTERNAL_INSTALL_DIR),)
>  ifneq ($(TOOLCHAIN_EXTERNAL_PREFIX),)
>  # if no path set, figure it out from path
> -TOOLCHAIN_EXTERNAL_BIN := $(dir $(shell which $(TOOLCHAIN_EXTERNAL_PREFIX)-gcc))
> +TOOLCHAIN_EXTERNAL_BIN := $(dir $(shell $(SHELL) -c "command -v '$(TOOLCHAIN_EXTERNAL_PREFIX)-gcc)'")
>  endif
>  else
>  TOOLCHAIN_EXTERNAL_REL_BIN_PATH = $(call qstrip,$(BR2_TOOLCHAIN_EXTERNAL_REL_BIN_PATH))
> -- 
> 2.33.0
> 
> _______________________________________________
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> buildroot@buildroot.org
> https://lists.buildroot.org/mailman/listinfo/buildroot

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