diff -rupN b/lib/package/ast-base.pkg a/lib/package/ast-base.pkg

--- b/lib/package/ast-base.pkg	2009-09-21 20:35:51.000000000 +0000

+++ a/lib/package/ast-base.pkg	2011-11-10 16:24:52.515495613 +0000

@@ -3,7 +3,7 @@ ast-base :PACKAGE: \

 		libdll libexpr libodelta librecsort libsum libuu libvdelta \

 		libbz libz tests 3d coshell cpp cs mam msgcc nmake probe ss \

 		libcoshell libcs libmam libpp libcodex paxlib codexlib \

 :COVERS: ast-make ast-ksh ast-ast

diff -rupN b/src/cmd/alias/alias.c a/src/cmd/alias/alias.c

--- b/src/cmd/alias/alias.c	1970-01-01 00:00:00.000000000 +0000

+++ a/src/cmd/alias/alias.c	2011-11-10 16:24:28.356925339 +0000

+/*

+ * CDDL HEADER START

+ *

+ * The contents of this file are subject to the terms of the

+ * Common Development and Distribution License (the "License").

+ * You may not use this file except in compliance with the License.

+ *

+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE

+ * or http://www.opensolaris.org/os/licensing.

+ * See the License for the specific language governing permissions

+ * and limitations under the License.

+ *

+ * When distributing Covered Code, include this CDDL HEADER in each

+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.

+ * If applicable, add the following below this CDDL HEADER, with the

+ * fields enclosed by brackets "[]" replaced with your own identifying

+ * information: Portions Copyright [yyyy] [name of copyright owner]

+ *

+ * CDDL HEADER END

+ */

+

+/*

+ */

+

+/*

+ * alias.c is a C version of the alias.sh wrapper (which links ksh

+ * builtins to commands in /usr/bin/, e.g. calling this wrapper as

+ * /usr/bin/alias will call the ksh "alias" builtin, running it as

+ * /usr/bin/cut will call the ksh "cut" builtin etc.

+ */

+

+#include <shell.h>

+#include <nval.h>

+#include <stdio.h>

+#include <alias.h>

+

+typedef struct {

+	const char *name;

+} bfastpathrec;

+

+/*

+ * We've disabled the "fastpath" codepath for some commands below

+ * because it causes a paradoxon for large input files (as used by

+ * ON PerfPIT for testing). For /usr/bin/rev (where the issue was

+ * first discovered) it looks like this:

+ * - for small files like /etc/profile the fastpath is faster in a loop

+ *   with 1000 iterations (8 seconds with fastpath, 14 seconds without

+ *   fastpath)

+ * - for large files (/usr/pub/UTF-8 replicated until the test file

+ *   reaches 24884706 bytes) the benchmark reverses: The fastpath now

+ *   needs 40 seconds and without fastpath it needs 30 seconds (for 100

+ *   iterations).

+ */

+#if 0

+#define	ENABLE_PERFORMANCE_PARADOXON 1

+#endif

+

+/*

+ * List of libcmd builtins which do not require a |Shell_t| context.

+ * This list was automatically generated from <ast/cmdext.h>

+ */

+static const

+bfastpathrec fastpath_builtins[] =

+{

+	/* This list must be alphabetically sorted for |strcmp()| usage */

+	{ "basename",	b_basename	},

+	{ "cat",	b_cat		},

+	{ "chgrp",	b_chgrp		},

+	{ "chmod",	b_chmod		},

+	{ "chown",	b_chown		},

+#ifdef ENABLE_PERFORMANCE_PARADOXON

+	{ "cksum",	b_cksum		},

+#endif /* ENABLE_PERFORMANCE_PARADOXON */

+	{ "cmp",	b_cmp		},

+	{ "comm",	b_comm		},

+	{ "cp",		b_cp		},

+	{ "cut",	b_cut		},

+	{ "date",	b_date		},

+	{ "dirname",	b_dirname	},

+	{ "expr",	b_expr		},

+	{ "fds",	b_fds		},

+	{ "fmt",	b_fmt		},

+	{ "fold",	b_fold		},

+	{ "getconf",	b_getconf	},

+	{ "head",	b_head		},

+	{ "id",		b_id		},

+	{ "join",	b_join		},

+	{ "ln",		b_ln		},

+	{ "logname",	b_logname	},

+	{ "md5sum",	b_md5sum	},

+	{ "mkdir",	b_mkdir		},

+	{ "mkfifo",	b_mkfifo	},

+	{ "mktemp",	b_mktemp	},

+	{ "mv",		b_mv		},

+	{ "paste",	b_paste 	},

+	{ "pathchk",	b_pathchk	},

+	{ "pids",	b_pids		},

+#ifdef ENABLE_PERFORMANCE_PARADOXON

+	{ "rev",	b_rev		},

+#endif /* ENABLE_PERFORMANCE_PARADOXON */

+	{ "rm",		b_rm		},

+	{ "rmdir",	b_rmdir		},

+	{ "stty",	b_stty		},

+#ifdef ENABLE_PERFORMANCE_PARADOXON

+	{ "sum",	b_sum		},

+#endif /* ENABLE_PERFORMANCE_PARADOXON */

+	{ "sync",	b_sync		},

+	{ "tail",	b_tail		},

+	{ "tee",	b_tee		},

+	{ "tty",	b_tty		},

+	{ "uname",	b_uname		},

+	{ "uniq",	b_uniq		},

+	{ "wc",		b_wc		},

+};

+

+static inline

+const bfastpathrec *

+find_bfastpathrec(const char *name)

+{

+	unsigned int i;

+	signed int cmpres;

+	for (i = 0; fastpath_builtins[i].name != NULL; i++) {

+		cmpres = strcmp(fastpath_builtins[i].name, name);

+		if (cmpres == 0)

+			return (&fastpath_builtins[i]);

+		else if (cmpres > 0)

+			return (NULL);

+

+	}

+	return (NULL);

+}

+

+static inline

+int

+fastpath_builtin_main(const bfastpathrec *brec, int argc, char *argv[])

+{

+	setlocale(LC_ALL, ""); /* calls |_ast_setlocale()| */

+

+	return ((*brec->func)(argc, argv, NULL));

+}

+

+

+/* Builtin script, original derived from alias.sh */

+static const char *script = "\n"

+/* Get name of builtin */

+"typeset cmd=\"${0##*/}\"\n"

+/*

+ * If the requested command is not an alias load it explicitly

+ * to make sure it is not bound to a path (those built-ins which

+ * are mapped via shell aliases point to commands which are

+ * "special shell built-ins" which cannot be bound to a specific

+ * PATH element) - otherwise we may execute the wrong command

+ * if an executable with the same name sits in a PATH element

+ * before /usr/bin (e.g. /usr/xpg4/bin/ls would be executed

+ * before /usr/bin/ls if the path was something like

+ * PATH=/usr/xpg4/bin:/usr/bin).

+ */

+"if [[ \"${cmd}\" != ~(Elr)(alias|unalias|command) ]] && "

+	"! alias \"${cmd}\" >/dev/null 2>&1 ; then\n"

+	"PATH='' builtin \"${cmd}\"\n"

+"fi\n"

+/* command is a keyword and needs to be handled separately */

+"if [[ \"${cmd}\" == \"command\" ]] ; then\n"

+	"command \"$@\"\n"

+"else\n"

+#ifdef WORKAROUND_FOR_ALIAS_CRASH

+/*

+ * Work around a crash in /usr/bin/alias when invalid options are

+ * passed (e.g. $ /usr/bin/alias -c #). The shell code will call

+ * an error handler which does a |longjmp()| but somehow the code

+ * failed to do the |setjmp()| before this point.

+ * Putting the "alias" command in a subshell avoids the crash.

+ * Real cause of the issue is under investigation and a fix be

+ * delivered with the next ast-ksh update.

+ */

+	"( \"${cmd}\" \"$@\" )\n"

+#else

+	"\"${cmd}\" \"$@\"\n"

+#endif /* WORKAROUND_FOR_ALIAS_CRASH */

+"fi\n"

+"exitval=$?";

+

+

+static inline

+int

+script_builtin_main(int argc, char *argv[])

+{

+	int i;

+	Shell_t *shp;

+	Namval_t *np;

+	int exitval;

+

+	/*

+	 * Create copy of |argv| array shifted by one position to

+	 * emulate $ /usr/bin/sh <scriptname> <args1> <arg2> ... #.

+	 * First position is set to "/usr/bin/sh" since other

+	 * values may trigger special shell modes (e.g. *rsh* will

+	 * trigger "restricted" shell mode etc.).

+	 */

+	char *xargv[argc+2];

+	xargv[0] = "/usr/bin/sh";

+	xargv[1] = "scriptname";

+	for (i = 0; i < argc; i++) {

+		xargv[i+1] = argv[i];

+	}

+	xargv[i+1] = NULL;

+

+	shp = sh_init(argc+1, xargv, 0);

+	if (!shp)

+		error(ERROR_exit(1), "shell initialisation failed.");

+	(void) sh_trap(script, 0);

+

+	np = nv_open("exitval", shp->var_tree, 0);

+	if (!np)

+		error(ERROR_exit(1), "variable %s not found.", "exitval");

+	exitval = (int)nv_getnum(np);

+	nv_close(np);

+

+	return (exitval);

+}

+

+int

+main(int argc, char *argv[])

+{

+	const char *progname;

+	const bfastpathrec *brec;

+	char execnamebuff[PATH_MAX+1];

+

+	/* Get program name */

+	if (pathprog(argv[0], execnamebuff, sizeof (execnamebuff)) <= 0)

+		error(ERROR_exit(1), "could not determinate exec name.");

+

+	progname = (const char *)strrchr(execnamebuff, '/');

+	if (progname != NULL) {

+		progname++;

+	}

+	else

+	{

+		progname = execnamebuff;

+	}

+

+	/* Execute command... */

+	if (brec = find_bfastpathrec(progname)) {

+		/* ... either via a fast path (calling the code directly) ... */

+		return (fastpath_builtin_main(brec, argc, argv));

+	}

+	else

+	{

+		/* ... or from within a full shell. */

+		return (script_builtin_main(argc, argv));

+	}

+}

diff -rupN b/src/cmd/alias/alias.h a/src/cmd/alias/alias.h

--- b/src/cmd/alias/alias.h	1970-01-01 00:00:00.000000000 +0000

+++ a/src/cmd/alias/alias.h	2011-11-10 16:24:28.357387725 +0000

+/***********************************************************************

+*                                                                      *

+*               This software is part of the ast package               *

+*                      and is licensed under the                       *

+*                    by AT&T Intellectual Property                     *

+*                                                                      *

+*                A copy of the License is available at                 *

+*                                                                      *

+*              Information and Software Systems Research               *

+*                            AT&T Research                             *

+*                           Florham Park NJ                            *

+*                                                                      *

+*                  David Korn <[email protected]>                   *

+*                                                                      *

+***********************************************************************/

+

diff -rupN b/src/cmd/alias/Makefile a/src/cmd/alias/Makefile

--- b/src/cmd/alias/Makefile	1970-01-01 00:00:00.000000000 +0000

+++ a/src/cmd/alias/Makefile	2011-11-10 16:24:28.357746164 +0000

@@ -0,0 +1,5 @@

+:PACKAGE: ast:static

+

+LICENSE = cddl

+libtype = :static

+alias :: RELEASE alias.c +lshell