build system: modernise shell compatibility checks

All changed files:
- Put the shell in POSIX mode if it has an '-o posix' option.
- Remove nonsense disabling 'set -x' on bash. It's not broken.

bin/package, src/cmd/INIT/package.sh:
- Add check blocking native zsh mode (e.g., "$path" conflicts).
  Using a 'sh -> zsh' symlink works, so recommend that.
- Remove old ksh93 version check for a supposed conflict with
  libcmd. It was broken; it would revert to /bin/sh, but on illumos
  distributions, /bin/sh is a ksh93 of a version that is supposedly
  affected. It builds fine anyway.
- Rewrite checksh() to incorporate the shell compatibility checks
  that were previously in two different places in 'package'.

bin/ignore, src/cmd/INIT/ignore.sh,
bin/silent, src/cmd/INIT/silent.sh:
- Change bad check for a full POSIX 'export' command (no, $RANDOM
  has nothing to do with that) with a proper feature test.

bin/ignore

@@ -20,18 +20,17 @@
 # non-ksh script for the nmake ignore prefix
 # @(#)ignore (AT&T Research) 1992-08-11
 
-case $-:$BASH_VERSION in
+(set -o posix) 2>/dev/null && set -o posix
-*x*:[0123456789]*)	: bash set -x is broken :; set +ex ;;
+modern_export=`v=; export v=ok 2>/dev/null; echo "$v"`
-esac
 
 while	:
 do	case $# in
 	0)	exit 0 ;;
 	esac
 	case $1 in
-	*=*)	case $RANDOM in
+	*=*)	case $modern_export in
-		$RANDOM)`echo $1 | sed "s/\\([^=]*\\)=\\(.*\\)/eval \\1='\\2'; export \\1/"` ;;
+		ok)	export "$1" ;;
-		*)	export "$1" ;;
+		*)	`echo $1 | sed "s/\\([^=]*\\)=\\(.*\\)/eval \\1='\\2'; export \\1/"` ;;
 		esac
 		shift
 		;;

bin/mamprobe

@@ -21,9 +21,7 @@
 # mamprobe - generate MAM cc probe info
 # Glenn Fowler <gsf@research.att.com>
 
-case $-:$BASH_VERSION in
+(set -o posix) 2>/dev/null && set -o posix
-*x*:[0123456789]*)	: bash set -x is broken :; set +ex ;;
-esac
 
 command=mamprobe
 

bin/package

@@ -24,37 +24,33 @@ USAGE_LICENSE="[-author?Glenn Fowler <gsf@research.att.com>][-copyright?Copyrigh
 
 command=package
 
-case $-:$BASH_VERSION in
+(set -o posix) 2>/dev/null && set -o posix
-*x*:[0123456789]*)	: bash set -x is broken :; set +ex ;;
+path=Bad
+case $PATH in
+Bad*)	echo "Cannot be run by zsh in native mode; use a sh symlink to zsh" >&2
+	exit 1 ;;
 esac
 
-# ksh checks -- ksh between 2007-11-05 and 2011-11-11 conflict with new -lcmd -- wea culpa
+# shell checks
 checksh()
 {
-	egrep 'Version.*(88|1993)' $1 >/dev/null 2>&1 ||
+	"$1" -ec '
-	PATH=/dev/null $1 -c '(( 2 + 2 ))' >/dev/null 2>&1 &&
+		# reject csh
-	$1 -c '(( .sh.version >= 20111111 ))' >/dev/null 2>&1
+		case 1 in
-}
+		1)	;;
-
-case $_AST_BIN_PACKAGE_:$SHELL:$0 in
-1:*:*|*:/bin/sh:*)
-	;;
-*:*/*:*/*)
-	_AST_BIN_PACKAGE_=1 # prevent non-interactive sh .rc referencing bin/package recursion #
-	export _AST_BIN_PACKAGE_
-	if	checksh $SHELL
-	then	: no -lcmd conflict :
-	else	case " $* " in
-		*" debug "*|*" DEBUG "*|*" show "*)
-			echo $command: $SHELL: warning: possible -lcmd conflict -- falling back to /bin/sh >&2
-			;;
 		esac
-		SHELL=/bin/sh
+		# reject special use of $path (to use zsh, use a "sh -> zsh" symlink, which disables this)
-		export SHELL
+		path=Bad
-		exec $SHELL "$0" "$@"
+		case $PATH in
-	fi
+		Bad*)	exit 1 ;;
-	;;
+		esac
-esac
+		# catch (our own) pipe/socket configuration mismatches
+		date | "$1" -c "read x" || exit 1
+		# check Bourne/POSIX compatible trap exit status (should exit with status 0)
+		trap "exit 0" 0
+		exit 1
+	' x "$1" 2>/dev/null || return 1
+}
 
 LC_ALL=C
 export LC_ALL
@@ -3103,26 +3099,7 @@ cat $INITROOT/$i.sh
 			;;
 		esac
 		;;
-	esac
+	*)	checksh $SHELL || SHELL=/bin/sh
-
-	# $SHELL must be /bin/sh compatible
-
-	case $SHELL in
-	/bin/sh);;
-	'')	SHELL=/bin/sh
-		;;
-	*)	$SHELL -c 'trap "exit 0" 0; exit 1' 2>/dev/null
-		case $? in
-		1)	SHELL=/bin/sh
-			;;
-		*)	# catch (our own) pipe/socket configuration mismatches
-			$SHELL -c "date | $SHELL -c 'read x'"
-			case $? in
-			0)	;;
-			*)	SHELL=/bin/sh ;;
-			esac
-			;;
-		esac
 		;;
 	esac
 	export SHELL

bin/silent

@@ -20,18 +20,17 @@
 # non-ksh stub for the nmake silent prefix
 # @(#)silent (AT&T Research) 1992-08-11
 
-case $-:$BASH_VERSION in
+(set -o posix) 2>/dev/null && set -o posix
-*x*:[01234567899]*)	: bash set -x is broken :; set +ex ;;
+modern_export=`v=; export v=ok 2>/dev/null; echo "$v"`
-esac
 
 while	:
 do	case $# in
 	0)	exit 0 ;;
 	esac
 	case $1 in
-	*=*)	case $RANDOM in
+	*=*)	case $modern_export in
-		$RANDOM)`echo $1 | sed "s/\\([^=]*\\)=\\(.*\\)/eval \\1='\\2'; export \\1/"` ;;
+		ok)	export "$1" ;;
-		*)	export "$1" ;;
+		*)	`echo $1 | sed "s/\\([^=]*\\)=\\(.*\\)/eval \\1='\\2'; export \\1/"` ;;
 		esac
 		shift
 		;;

src/cmd/INIT/crossexec.sh

@@ -19,6 +19,8 @@
 ########################################################################
 : cross compiler a.out execution
 
+(set -o posix) 2>/dev/null && set -o posix
+
 command=crossexec
 
 tmp=/tmp/cross$$

src/cmd/INIT/execrate.sh

@@ -19,6 +19,8 @@
 ########################################################################
 : wrapper for .exe challenged win32 systems/commands
 
+(set -o posix) 2>/dev/null && set -o posix
+
 command=execrate
 
 bins=`

src/cmd/INIT/filter.sh

@@ -19,6 +19,8 @@
 ########################################################################
 : convert command that operates on file args to pipeline filter
 
+(set -o posix) 2>/dev/null && set -o posix
+
 command=filter
 
 TMPDIR=${TMPDIR:-/tmp}

src/cmd/INIT/hurl.sh

@@ -19,6 +19,8 @@
 ########################################################################
 : copy http url data
 
+(set -o posix) 2>/dev/null && set -o posix
+
 command=hurl
 agent="$command/2009-01-20 (AT&T Research)"
 authorize=

src/cmd/INIT/iffe.sh

@@ -25,9 +25,7 @@
 #
 # NOTE: .exe a.out suffix and [\\/] in path patterns for dos/nt
 
-case $-:$BASH_VERSION in
+(set -o posix) 2>/dev/null && set -o posix
-*x*:[0123456789]*)	: bash set -x is broken :; set +ex ;;
-esac
 
 command=iffe
 version=2012-07-17 # update in USAGE too #

src/cmd/INIT/ignore.sh

@@ -20,18 +20,17 @@
 # non-ksh script for the nmake ignore prefix
 # @(#)ignore (AT&T Research) 1992-08-11
 
-case $-:$BASH_VERSION in
+(set -o posix) 2>/dev/null && set -o posix
-*x*:[0123456789]*)	: bash set -x is broken :; set +ex ;;
+modern_export=`v=; export v=ok 2>/dev/null; echo "$v"`
-esac
 
 while	:
 do	case $# in
 	0)	exit 0 ;;
 	esac
 	case $1 in
-	*=*)	case $RANDOM in
+	*=*)	case $modern_export in
-		$RANDOM)`echo $1 | sed "s/\\([^=]*\\)=\\(.*\\)/eval \\1='\\2'; export \\1/"` ;;
+		ok)	export "$1" ;;
-		*)	export "$1" ;;
+		*)	`echo $1 | sed "s/\\([^=]*\\)=\\(.*\\)/eval \\1='\\2'; export \\1/"` ;;
 		esac
 		shift
 		;;

src/cmd/INIT/mamprobe.sh

@@ -21,9 +21,7 @@
 # mamprobe - generate MAM cc probe info
 # Glenn Fowler <gsf@research.att.com>
 
-case $-:$BASH_VERSION in
+(set -o posix) 2>/dev/null && set -o posix
-*x*:[0123456789]*)	: bash set -x is broken :; set +ex ;;
-esac
 
 command=mamprobe
 

src/cmd/INIT/mkdir.sh

@@ -19,7 +19,10 @@
 #                                                                      #
 ########################################################################
 : mkdir for systems that do not support -p : 2002-09-01 :
-MKDIR=/bin/mkdir
+
+(set -o posix) 2>/dev/null && set -o posix
+
+MKDIR=mkdir
 CHMOD=chmod
 mode=
 parents=

src/cmd/INIT/package.sh

@@ -23,37 +23,33 @@
 
 command=package
 
-case $-:$BASH_VERSION in
+(set -o posix) 2>/dev/null && set -o posix
-*x*:[0123456789]*)	: bash set -x is broken :; set +ex ;;
+path=Bad
+case $PATH in
+Bad*)	echo "Cannot be run by zsh in native mode; use a sh symlink to zsh" >&2
+	exit 1 ;;
 esac
 
-# ksh checks -- ksh between 2007-11-05 and 2011-11-11 conflict with new -lcmd -- wea culpa
+# shell checks
 checksh()
 {
-	egrep 'Version.*(88|1993)' $1 >/dev/null 2>&1 ||
+	"$1" -ec '
-	PATH=/dev/null $1 -c '(( 2 + 2 ))' >/dev/null 2>&1 &&
+		# reject csh
-	$1 -c '(( .sh.version >= 20111111 ))' >/dev/null 2>&1
+		case 1 in
-}
+		1)	;;
-
-case $_AST_BIN_PACKAGE_:$SHELL:$0 in
-1:*:*|*:/bin/sh:*)
-	;;
-*:*/*:*/*)
-	_AST_BIN_PACKAGE_=1 # prevent non-interactive sh .rc referencing bin/package recursion #
-	export _AST_BIN_PACKAGE_
-	if	checksh $SHELL
-	then	: no -lcmd conflict :
-	else	case " $* " in
-		*" debug "*|*" DEBUG "*|*" show "*)
-			echo $command: $SHELL: warning: possible -lcmd conflict -- falling back to /bin/sh >&2
-			;;
 		esac
-		SHELL=/bin/sh
+		# reject special use of $path (to use zsh, use a "sh -> zsh" symlink, which disables this)
-		export SHELL
+		path=Bad
-		exec $SHELL "$0" "$@"
+		case $PATH in
-	fi
+		Bad*)	exit 1 ;;
-	;;
+		esac
-esac
+		# catch (our own) pipe/socket configuration mismatches
+		date | "$1" -c "read x" || exit 1
+		# check Bourne/POSIX compatible trap exit status (should exit with status 0)
+		trap "exit 0" 0
+		exit 1
+	' x "$1" 2>/dev/null || return 1
+}
 
 LC_ALL=C
 export LC_ALL
@@ -3102,26 +3098,7 @@ cat $INITROOT/$i.sh
 			;;
 		esac
 		;;
-	esac
+	*)	checksh $SHELL || SHELL=/bin/sh
-
-	# $SHELL must be /bin/sh compatible
-
-	case $SHELL in
-	/bin/sh);;
-	'')	SHELL=/bin/sh
-		;;
-	*)	$SHELL -c 'trap "exit 0" 0; exit 1' 2>/dev/null
-		case $? in
-		1)	SHELL=/bin/sh
-			;;
-		*)	# catch (our own) pipe/socket configuration mismatches
-			$SHELL -c "date | $SHELL -c 'read x'"
-			case $? in
-			0)	;;
-			*)	SHELL=/bin/sh ;;
-			esac
-			;;
-		esac
 		;;
 	esac
 	export SHELL

src/cmd/INIT/silent.sh

@@ -20,18 +20,17 @@
 # non-ksh stub for the nmake silent prefix
 # @(#)silent (AT&T Research) 1992-08-11
 
-case $-:$BASH_VERSION in
+(set -o posix) 2>/dev/null && set -o posix
-*x*:[01234567899]*)	: bash set -x is broken :; set +ex ;;
+modern_export=`v=; export v=ok 2>/dev/null; echo "$v"`
-esac
 
 while	:
 do	case $# in
 	0)	exit 0 ;;
 	esac
 	case $1 in
-	*=*)	case $RANDOM in
+	*=*)	case $modern_export in
-		$RANDOM)`echo $1 | sed "s/\\([^=]*\\)=\\(.*\\)/eval \\1='\\2'; export \\1/"` ;;
+		ok)	export "$1" ;;
-		*)	export "$1" ;;
+		*)	`echo $1 | sed "s/\\([^=]*\\)=\\(.*\\)/eval \\1='\\2'; export \\1/"` ;;
 		esac
 		shift
 		;;

src/cmd/ksh93/features/math.sh

@@ -22,6 +22,11 @@
 
 # @(#)math.sh (AT&T Research) 2012-06-13
 
+case $ZSH_VERSION in
+?*)	emulate ksh ;;
+*)	(set -o posix) 2>/dev/null && set -o posix ;;
+esac
+
 command=$0
 iffeflags="-n -v"
 iffehdrs="math.h"

src/lib/libast/comp/conf.sh

@@ -34,8 +34,9 @@
 # but you shall be confused anyway
 #
 
-case $-:$BASH_VERSION in
+case $ZSH_VERSION in
-*x*:[0123456789]*)	: bash set -x is broken :; set +ex ;;
+?*)	emulate ksh ;;
+*)	(set -o posix) 2>/dev/null && set -o posix ;;
 esac
 
 LC_ALL=C

src/lib/libast/features/libpath.sh

@@ -19,6 +19,12 @@
 #                   Phong Vo <kpv@research.att.com>                    #
 #                                                                      #
 ########################################################################
+
+case $ZSH_VERSION in
+?*)	emulate ksh ;;
+*)	(set -o posix) 2>/dev/null && set -o posix ;;
+esac
+
 ok=0
 for i in \
 	-x /lib/ld.so /lib/ld-*.so /usr/lib/ld.so /lib/rld \

src/lib/libast/features/param.sh

@@ -20,6 +20,12 @@
 #                                                                      #
 ########################################################################
 : generate "<sys/param.h> + <sys/types.h> + <sys/stat.h>" include sequence
+
+case $ZSH_VERSION in
+?*)	emulate ksh ;;
+*)	(set -o posix) 2>/dev/null && set -o posix ;;
+esac
+
 case $# in
 0)	;;
 *)	eval $1

src/lib/libast/features/preroot.sh

@@ -20,6 +20,12 @@
 #                                                                      #
 ########################################################################
 : generate preroot features
+
+case $ZSH_VERSION in
+?*)	emulate ksh ;;
+*)	(set -o posix) 2>/dev/null && set -o posix ;;
+esac
+
 case $# in
 0)	;;
 *)	eval $1

src/lib/libast/features/sig.sh

@@ -20,6 +20,12 @@
 #                                                                      #
 ########################################################################
 : generate sig features
+
+case $ZSH_VERSION in
+?*)	emulate ksh ;;
+*)	(set -o posix) 2>/dev/null && set -o posix ;;
+esac
+
 case $# in
 0)	;;
 *)	eval $1