• Allow setting both -o posix and -o sh (although only in the same

command; setting one still unsets the other at first)
• Change subst_exstat to be conformant unless -o sh is set and -o posix isn’t
• In lksh, make subst_exstat (newly) conformant if -o posix
• New MKSH_BINSHPOSIX to accompany MKSH_BINSHREDUCED
• Sync lksh manpage precisely

Build.sh

@@ -1,5 +1,5 @@
 #!/bin/sh
-srcversion='$MirOS: src/bin/mksh/Build.sh,v 1.628 2013/04/27 18:12:37 tg Exp $'
+srcversion='$MirOS: src/bin/mksh/Build.sh,v 1.629 2013/05/02 20:21:36 tg Exp $'
 #-
 # Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
 #		2011, 2012, 2013
@@ -1367,8 +1367,8 @@ if ac_ifcpp 'ifdef MKSH_SMALL' isset_MKSH_SMALL '' \
 	check_categories="$check_categories smksh"
 	HAVE_ISSET_MKSH_CONSERVATIVE_FDS=1	# from sh.h
 fi
-ac_ifcpp 'ifdef MKSH_BINSHREDUCED' isset_MKSH_BINSHREDUCED '' \
+ac_ifcpp 'if defined(MKSH_BINSHPOSIX) || defined(MKSH_BINSHREDUCED)' \
-    "if a reduced-feature sh is requested" && \
+    isset_MKSH_BINSH '' 'if invoking as sh should be handled specially' && \
     check_categories="$check_categories binsh"
 ac_ifcpp 'ifdef MKSH_UNEMPLOYED' isset_MKSH_UNEMPLOYED '' \
     "if mksh will be built without job control" && \
@@ -1531,7 +1531,7 @@ else
 		#define EXTERN
 		#define MKSH_INCLUDES_ONLY
 		#include "sh.h"
-		__RCSID("$MirOS: src/bin/mksh/Build.sh,v 1.628 2013/04/27 18:12:37 tg Exp $");
+		__RCSID("$MirOS: src/bin/mksh/Build.sh,v 1.629 2013/05/02 20:21:36 tg Exp $");
 		int main(void) { printf("Hello, World!\n"); return (0); }
 EOF
 	case $cm in
@@ -2315,6 +2315,7 @@ DEBUG_LEAKS			enable freeing resources before exiting
 MKSHRC_PATH			"~/.mkshrc" (do not change)
 MKSH_A4PB			force use of arc4random_pushb
 MKSH_ASSUME_UTF8		(0=disabled, 1=enabled; default: unset)
+MKSH_BINSHPOSIX			if */sh or */-sh, enable set -o posix
 MKSH_BINSHREDUCED		if */sh or */-sh, enable set -o sh
 MKSH_CLRTOEOL_STRING		"\033[K"
 MKSH_CLS_STRING			"\033[;H\033[J"

check.t

@@ -1,4 +1,4 @@
-# $MirOS: src/bin/mksh/check.t,v 1.609 2013/04/27 19:16:23 tg Exp $
+# $MirOS: src/bin/mksh/check.t,v 1.610 2013/05/02 20:21:38 tg Exp $
 # $OpenBSD: bksl-nl.t,v 1.2 2001/01/28 23:04:56 niklas Exp $
 # $OpenBSD: history.t,v 1.5 2001/01/28 23:04:56 niklas Exp $
 # $OpenBSD: read.t,v 1.3 2003/03/10 03:48:16 david Exp $
@@ -4254,7 +4254,7 @@ description:
 	should print 0 according to POSIX (dash, bash, ksh93, posh)
 	but not 0 according to the getopt(1) manual page, ksh88, and
 	Bourne sh (such as /bin/sh on Solaris).
-	In mksh R39b, we honour POSIX except when -o sh is set.
+	We honour POSIX except when -o sh is set.
 category: shell:legacy-no
 stdin:
 	showf() {
@@ -4274,10 +4274,15 @@ stdin:
 	showf
 	set -- `false`
 	echo rv=$?
+	set -o posix -o sh
+	showf
+	set -- `false`
+	echo rv=$?
 expected-stdout:
 	FPOSIX=0 FSH=0 rv=0
 	FPOSIX=0 FSH=1 rv=1
 	FPOSIX=1 FSH=0 rv=0
+	FPOSIX=1 FSH=1 rv=0
 ---
 name: regression-10-legacy
 description:
@@ -4306,10 +4311,15 @@ stdin:
 	showf
 	set -- `false`
 	echo rv=$?
+	set -o posix -o sh
+	showf
+	set -- `false`
+	echo rv=$?
 expected-stdout:
 	FPOSIX=0 FSH=0 rv=1
 	FPOSIX=0 FSH=1 rv=1
-	FPOSIX=1 FSH=0 rv=1
+	FPOSIX=1 FSH=0 rv=0
+	FPOSIX=1 FSH=1 rv=0
 ---
 name: regression-11
 description:
@@ -6187,7 +6197,7 @@ expected-stdout:
 ---
 name: sh-mode-2a
 description:
-	Check that sh mode is *not* automatically turned on
+	Check that posix or sh mode is *not* automatically turned on
 category: !binsh
 stdin:
 	ln -s "$__progname" ksh || cp "$__progname" ksh
@@ -6196,7 +6206,7 @@ stdin:
 	ln -s "$__progname" ./-sh || cp "$__progname" ./-sh
 	for shell in {,-}{,k}sh; do
 		print -- $shell $(./$shell +l -c \
-		    '[[ $(set +o) == *@(-o sh)@(| *) ]] && echo sh || echo nosh')
+		    '[[ $(set +o) == *"-o "@(sh|posix)@(| *) ]] && echo sh || echo nosh')
 	done
 expected-stdout:
 	sh nosh
@@ -6206,7 +6216,7 @@ expected-stdout:
 ---
 name: sh-mode-2b
 description:
-	Check that sh mode *is* automatically turned on
+	Check that posix or sh mode *is* automatically turned on
 category: binsh
 stdin:
 	ln -s "$__progname" ksh || cp "$__progname" ksh
@@ -6215,7 +6225,7 @@ stdin:
 	ln -s "$__progname" ./-sh || cp "$__progname" ./-sh
 	for shell in {,-}{,k}sh; do
 		print -- $shell $(./$shell +l -c \
-		    '[[ $(set +o) == *@(-o sh)@(| *) ]] && echo sh || echo nosh')
+		    '[[ $(set +o) == *"-o "@(sh|posix)@(| *) ]] && echo sh || echo nosh')
 	done
 expected-stdout:
 	sh sh

funcs.c

@@ -38,7 +38,7 @@
 #endif
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/funcs.c,v 1.242 2013/04/26 21:22:45 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/funcs.c,v 1.243 2013/05/02 20:21:41 tg Exp $");
 
 #if HAVE_KILLPG
 /*
@@ -2426,12 +2426,13 @@ c_set(const char **wp)
 	 * which assumes the exit value set will be that of the $()
 	 * (subst_exstat is cleared in execute() so that it will be 0
 	 * if there are no command substitutions).
-	 * Switched ksh (!posix !sh) to POSIX in mksh R39b.
 	 */
 #ifdef MKSH_LEGACY_MODE
-	return (subst_exstat);
+	/* traditional behaviour, unless set -o posix */
+	return (Flag(FPOSIX) ? 0 : subst_exstat);
 #else
-	return (Flag(FSH) ? subst_exstat : 0);
+	/* conformant behaviour, unless set -o sh +o posix */
+	return (Flag(FSH) && !Flag(FPOSIX) ? subst_exstat : 0);
 #endif
 }
 

lksh.1

@@ -1,4 +1,4 @@
-.\" $MirOS: src/bin/mksh/lksh.1,v 1.3 2013/04/27 19:16:25 tg Exp $
+.\" $MirOS: src/bin/mksh/lksh.1,v 1.4 2013/05/02 20:21:43 tg Exp $
 .\"-
 .\" Copyright (c) 2008, 2009, 2010, 2012, 2013
 .\"	Thorsten “mirabilos” Glaser <tg@mirbsd.org>
@@ -72,7 +72,7 @@
 .\" with -mandoc, it might implement .Mx itself, but we want to
 .\" use our own definition. And .Dd must come *first*, always.
 .\"
-.Dd $Mdocdate: April 27 2013 $
+.Dd $Mdocdate: May 2 2013 $
 .\"
 .\" Check which macro package we use, and do other -mdoc setup.
 .\"
@@ -184,7 +184,7 @@ is not suitable for use as
 .Pa /bin/sh .
 .It
 There is no explicit support for interactive use,
-nor any command line editing code.
+nor any command line editing or history code.
 Hence,
 .Nm
 is not suitable as a user's login shell, either; use
@@ -200,19 +200,43 @@ as
 instead of
 .Dq MIRBSD KSH .
 .It
-Some
+.Nm
-.Nm mksh
+only offers the traditional ten file descriptors to scripts.
-specific extensions are missing; specifically, the
-.Fl T
-command-line option.
 .It
-Some extensions from other shells, such as
+.Nm
+uses
+.Tn POSIX
+arithmetics, which has quite a few implications:
+The data type for arithmetics is the host ISO C
+.Vt long
+data type.
+Signed integer wraparound is Undefined Behaviour.
+The sign of the result of a modulo operation with at least one
+negative operand is unspecified.
+Shift operations on negative numbers are unspecified.
+Division of the largest negative number by \-1 is Undefined Behaviour.
+The compiler is permitted to delete all data and crash the system
+if Undefined Behaviour occurs.
+.It
+The rotation arithmetic operators are not available.
+.It
+The shift arithmetic operators take all bits of the second operand into
+account; if they exceed permitted precision, the result is unspecified.
+.It
+The
 .Tn GNU
-.Nm bash ,
+.Nm bash
-which
+extension &\*(Gt to redirect stdout and stderr in one go is not parsed.
-.Nm mksh
-provides, are missing, for increased compatibility with legacy scripts.
 .It
+The
+.Nm mksh
+command line option
+.Fl T
+is not available.
+.It
+Unless
+.Ic set -o posix
+is active,
 .Nm
 always uses traditional mode for constructs like:
 .Bd -literal -offset indent
@@ -230,27 +254,6 @@ unlike
 .At
 .Nm ksh ,
 does not keep file descriptors \*(Gt 2 private.
-.It
-Integers use the host C environment's
-.Vt long
-type, not
-.Vt int32_t .
-Unsigned arithmetic is done using
-.Vt unsigned long ,
-not
-.Vt uint32_t .
-Neither value limits nor wraparound is guaranteed.
-Dividing the largest negative number by \-1 is Undefined Behaviour
-.Po
-but might work on 32-bit and 64-bit
-.Vt long
-types
-.Pc .
-POSIX, by virtue of including ISO C, makes it legal for code triggering
-Undefined Behaviour to remove all your data and crash the system!
-.It
-.Nm
-only offers the traditional ten file descriptors to scripts.
 .El
 .Sh SEE ALSO
 .Xr mksh 1

main.c

@@ -34,7 +34,7 @@
 #include <locale.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/main.c,v 1.263 2013/04/27 18:56:41 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/main.c,v 1.264 2013/05/02 20:21:43 tg Exp $");
 
 extern char **environ;
 
@@ -251,10 +251,19 @@ main_init(int argc, const char *argv[], Source **sp, struct block **lp)
 		if (argi < 0)
 			return (1);
 
+#if defined(MKSH_BINSHPOSIX) || defined(MKSH_BINSHREDUCED)
+		/* are we called as -sh or /bin/sh or so? */
+		if (!strcmp(ccp, "sh")) {
+			/* either also turns off braceexpand */
+#ifdef MKSH_BINSHPOSIX
+			/* enable better POSIX conformance */
+			change_flag(FPOSIX, OF_FIRSTTIME, true);
+#endif
 #ifdef MKSH_BINSHREDUCED
-		/* set FSH if we're called as -sh or /bin/sh or so */
+			/* enable kludge/compat mode */
-		if (!strcmp(ccp, "sh"))
 			change_flag(FSH, OF_FIRSTTIME, true);
+#endif
+		}
 #endif
 	}
 

misc.c

@@ -30,7 +30,7 @@
 #include <grp.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/misc.c,v 1.210 2013/04/27 19:09:13 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/misc.c,v 1.211 2013/05/02 20:21:44 tg Exp $");
 
 #define KSH_CHVT_FLAG
 #ifdef MKSH_SMALL
@@ -277,11 +277,10 @@ change_flag(enum sh_flag f, int what, bool newset)
 		setgid(kshegid);
 #endif
 	} else if ((f == FPOSIX || f == FSH) && newval) {
-		Flag(FPOSIX) = Flag(FSH) = Flag(FBRACEEXPAND) = 0;
+		/* Turning on -o posix or -o sh? */
-		Flag(f) = newval;
+		Flag(FBRACEEXPAND) = 0;
-	}
+	} else if (f == FTALKING) {
 		/* Changing interactive flag? */
-	if (f == FTALKING) {
 		if ((what == OF_CMDLINE || what == OF_SET) && procpid == kshpid)
 			Flag(FTALKING_I) = newval;
 	}
@@ -306,6 +305,7 @@ parse_args(const char **argv,
 	size_t i;
 	int optc, arrayset = 0;
 	bool sortargs = false;
+	bool fcompatseen = false;
 
 	/* First call? Build option strings... */
 	if (cmd_opts[0] == '\0') {
@@ -379,6 +379,17 @@ parse_args(const char **argv,
 				break;
 			}
 			i = option(go.optarg);
+			if ((i == FPOSIX || i == FSH) && set && !fcompatseen) {
+				/*
+				 * If running 'set -o posix' or
+				 * 'set -o sh', turn off the other;
+				 * if running 'set -o posix -o sh'
+				 * allow both to be set though.
+				 */
+				Flag(FPOSIX) = 0;
+				Flag(FSH) = 0;
+				fcompatseen = true;
+			}
 			if ((i != (size_t)-1) && (set ? 1U : 0U) == Flag(i))
 				/*
 				 * Don't check the context if the flag

sh_flags.h

@@ -1,5 +1,5 @@
 #if defined(SHFLAGS_DEFNS)
-__RCSID("$MirOS: src/bin/mksh/sh_flags.h,v 1.12 2012/06/28 20:14:17 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/sh_flags.h,v 1.13 2013/05/02 20:21:45 tg Exp $");
 #define FN(sname,cname,ochar,flags)	/* nothing */
 #elif defined(SHFLAGS_ENUMS)
 #define FN(sname,cname,ochar,flags)	cname,
@@ -88,7 +88,7 @@ FN("nounset", FNOUNSET, 'u', OF_ANY)
 /* ./.	don't do logical cds/pwds (non-standard) */
 FN("physical", FPHYSICAL, 0, OF_ANY)
 
-/* ./.	pdksh compat: somewhat more POSIXish mode (non-standard) */
+/* ./.	adhere more closely to POSIX even when undesirable */
 FN("posix", FPOSIX, 0, OF_ANY)
 
 /* -p	use suid_profile; privileged shell */
@@ -97,7 +97,7 @@ FN("privileged", FPRIVILEGED, 'p', OF_ANY)
 /* -r	restricted shell */
 FN("restricted", FRESTRICTED, 'r', OF_CMDLINE)
 
-/* ./.	pdksh compat: called as sh not mksh; kludge mode (non-standard) */
+/* ./.	kludge mode for better compat with traditional sh (OS-specific) */
 FN("sh", FSH, 0, OF_ANY)
 
 /* -s	(invocation) parse stdin (pseudo non-standard) */