Factor out all the .SHELL parsing related stuff into its own file and

rename the function to be consistent with the naming scheme in the rest
of make. No functional changes.

Obtained from:	DragonFlyBSD (idea and most of shell.h)

7 files changed, 588 insertions, 477 deletions

diff --git a/usr.bin/make/Makefile b/usr.bin/make/Makefile
index 3cb53693..7252a25 100644
--- a/usr.bin/make/Makefile
+++ b/usr.bin/make/Makefile
@@ -5,7 +5,8 @@
 PROG=	make
 CFLAGS+=-I${.CURDIR}
 SRCS=	arch.c buf.c cond.c dir.c for.c hash.c hash_tables.c job.c	\
-	lst.c main.c make.c parse.c str.c suff.c targ.c util.c var.c
+	lst.c main.c make.c parse.c shell.c str.c suff.c targ.c util.c	\
+	var.c
 
 NO_WERROR=
 WARNS?=	3
diff --git a/usr.bin/make/job.c b/usr.bin/make/job.c
index 6567afd..e4e04e5 100644
--- a/usr.bin/make/job.c
+++ b/usr.bin/make/job.c
@@ -76,10 +76,6 @@ __FBSDID("$FreeBSD$");
  *
  *	Job_Empty	Return TRUE if the job table is completely empty.
  *
- *	Job_ParseShell	Given the line following a .SHELL target, parse the
- *			line as a shell specification. Returns FALSE if the
- *			spec was incorrect.
- *
  *	Job_Finish	Perform any final processing which needs doing. This
  *			includes the execution of any commands which have
  *			been/were attached to the .END target. It should only
@@ -138,6 +134,7 @@ __FBSDID("$FreeBSD$");
 #include "make.h"
 #include "parse.h"
 #include "pathnames.h"
+#include "shell.h"
 #include "str.h"
 #include "suff.h"
 #include "targ.h"
@@ -268,60 +265,6 @@ typedef struct Job {
 TAILQ_HEAD(JobList, Job);
 
 /*
- * Shell Specifications:
- *
- * Some special stuff goes on if a shell doesn't have error control. In such
- * a case, errCheck becomes a printf template for echoing the command,
- * should echoing be on and ignErr becomes another printf template for
- * executing the command while ignoring the return status. If either of these
- * strings is empty when hasErrCtl is FALSE, the command will be executed
- * anyway as is and if it causes an error, so be it.
- */
-struct Shell {
-	TAILQ_ENTRY(Shell) link;	/* link all shell descriptions */
-
-	/*
-	 * the name of the shell. For Bourne and C shells, this is used
-	 * only to find the shell description when used as the single
-	 * source of a .SHELL target. For user-defined shells, this is
-	 * the full path of the shell.
-	 */
-	char	*name;
-	char	*path;
-
-	/* True if both echoOff and echoOn defined */
-	Boolean	hasEchoCtl;
-
-	char	*echoOff;	/* command to turn off echo */
-	char	*echoOn;	/* command to turn it back on */
-
-	/*
-	 * What the shell prints, when given the echo-off command.
-	 * This line will not be printed when received from the shell.
-	 * This is usually the command which was executed to turn off echoing.
-	 */
-	char	*noPrint;
-
-	/* set if can control error checking for individual commands */
-	Boolean	hasErrCtl;
-
-	/* string to turn error checking on */
-	char	*errCheck;
-
-	/* string to turn off error checking */
-	char	*ignErr;
-
-	char	*echo;	/* command line flag: echo commands */
-	char	*exit;	/* command line flag: exit on error */
-
-	ArgArray builtins;
-	char	*meta;
-
-	Boolean	unsetenv;	/* unsetenv("ENV") before exec */
-};
-TAILQ_HEAD(Shells, Shell);
-
-/*
  * error handling variables
  */
 static int	errors = 0;	/* number of errors reported */
@@ -358,76 +301,6 @@ static int	numCommands;
 #define	JOB_STOPPED	3	/* The job is stopped */
 
 /*
- * Descriptions for various shells. What the list of builtins should contain
- * is debatable: either all builtins or only those which may specified on
- * a single line without use of meta-characters. For correct makefiles that
- * contain only correct command lines there is no difference. But if a command
- * line, for example, is: 'if -foo bar' and there is an executable named 'if'
- * in the path, the first possibility would execute that 'if' while in the
- * second case the shell would give an error. Histerically only a small
- * subset of the builtins and no reserved words where given in the list which
- * corresponds roughly to the first variant. So go with this but add missing
- * words.
- */
-#define	CSH_BUILTINS						\
-	"alias cd eval exec exit read set ulimit unalias "	\
-	"umask unset wait"
-
-#define	SH_BUILTINS						\
-	"alias cd eval exec exit read set ulimit unalias "	\
-	"umask unset wait"
-
-#define	CSH_META	"#=|^(){};&<>*?[]:$`\\@\n"
-#define	SH_META		"#=|^(){};&<>*?[]:$`\\\n"
-
-static const char *const shells_init[] = {
-	/*
-	 * CSH description. The csh can do echo control by playing
-	 * with the setting of the 'echo' shell variable. Sadly,
-	 * however, it is unable to do error control nicely.
-	 */
-	"name=csh path='" PATH_DEFSHELLDIR "/csh' "
-	"quiet='unset verbose' echo='set verbose' filter='unset verbose' "
-	"hasErrCtl=N check='echo \"%s\"\n' ignore='csh -c \"%s || exit 0\"' "
-	"echoFlag=v errFlag=e "
-	"meta='" CSH_META "' builtins='" CSH_BUILTINS "'",
-
-	/*
-	 * SH description. Echo control is also possible and, under
-	 * sun UNIX anyway, one can even control error checking.
-	 */
-	"name=sh path='" PATH_DEFSHELLDIR "/sh' "
-	"quiet='set -' echo='set -v' filter='set -' "
-	"hasErrCtl=Y check='set -e' ignore='set +e' "
-	"echoFlag=v errFlag=e "
-	"meta='" SH_META "' builtins='" SH_BUILTINS "'",
-
-	/*
-	 * KSH description. The Korn shell has a superset of
-	 * the Bourne shell's functionality. There are probably builtins
-	 * missing here.
-	 */
-	"name=ksh path='" PATH_DEFSHELLDIR "/ksh' "
-	"quiet='set -' echo='set -v' filter='set -' "
-	"hasErrCtl=Y check='set -e' ignore='set +e' "
-	"echoFlag=v errFlag=e "
-	"meta='" SH_META "' builtins='" SH_BUILTINS "' unsetenv=T",
-
-	NULL
-};
-
-/*
- * This is the shell to which we pass all commands in the Makefile.
- * It is set by the Job_ParseShell function.
- */
-static struct Shell *commandShell = NULL;
-
-/*
- * This is the list of all known shells.
- */
-static struct Shells shells = TAILQ_HEAD_INITIALIZER(shells);
-
-/*
  * The maximum number of jobs that may run. This is initialize from the
  * -j argument for the leading make and from the FIFO for sub-makes.
  */
@@ -527,12 +400,10 @@ typedef struct ProcStuff {
 static void JobRestart(Job *);
 static int JobStart(GNode *, int, Job *);
 static void JobDoOutput(Job *, Boolean);
-static struct Shell *JobMatchShell(const char *);
 static void JobInterrupt(int, int);
 static void JobRestartJobs(void);
 static void ProcExec(const ProcStuff *) __dead2;
 static int Compat_RunCommand(char *, struct GNode *);
-static void JobShellDump(const struct Shell *) __unused;
 
 static GNode	    *curTarg = NULL;
 static GNode	    *ENDNode;
@@ -2531,199 +2402,6 @@ Job_Make(GNode *gn)
 	JobStart(gn, 0, NULL);
 }
 
-static int
-sort_builtins(const void *p1, const void *p2)
-{
-
-	return (strcmp(*(const char* const*)p1, *(const char* const*)p2));
-}
-
-/**
- * JobFreeShell
- *	Free a shell structure and all associated strings.
- */
-static void
-JobFreeShell(struct Shell *sh)
-{
-
-	if (sh != NULL) {
-		free(sh->name);
-		free(sh->path);
-		free(sh->echoOff);
-		free(sh->echoOn);
-		free(sh->noPrint);
-		free(sh->errCheck);
-		free(sh->ignErr);
-		free(sh->echo);
-		free(sh->exit);
-		ArgArray_Done(&sh->builtins);
-		free(sh->meta);
-		free(sh);
-	}
-}
-
-/**
- * Dump a shell specification to stderr.
- */
-static void
-JobShellDump(const struct Shell *sh)
-{
-	int i;
-
-	fprintf(stderr, "Shell %p:\n", sh);
-	fprintf(stderr, "  name='%s' path='%s'\n", sh->name, sh->path);
-	fprintf(stderr, "  hasEchoCtl=%d echoOff='%s' echoOn='%s'\n",
-	    sh->hasEchoCtl, sh->echoOff, sh->echoOn);
-	fprintf(stderr, "  noPrint='%s'\n", sh->noPrint);
-	fprintf(stderr, "  hasErrCtl=%d errCheck='%s' ignErr='%s'\n",
-	    sh->hasErrCtl, sh->errCheck, sh->ignErr);
-	fprintf(stderr, "  echo='%s' exit='%s'\n", sh->echo, sh->exit);
-	fprintf(stderr, "  builtins=%d\n", sh->builtins.argc - 1);
-	for (i = 1; i < sh->builtins.argc; i++)
-		fprintf(stderr, " '%s'", sh->builtins.argv[i]);
-	fprintf(stderr, "\n  meta='%s'\n", sh->meta);
-	fprintf(stderr, "  unsetenv=%d\n", sh->unsetenv);
-}
-
-/**
- * Parse a shell specification line and return the new Shell structure.
- * In case of an error a message is printed and NULL is returned.
- */
-static struct Shell *
-JobParseShellSpec(const char *spec, Boolean *fullSpec)
-{
-	ArgArray	aa;
-	struct Shell	*sh;
-	char		*eq;
-	char		*keyw;
-	int		arg;
-
-	*fullSpec = FALSE;
-
-	sh = emalloc(sizeof(*sh));
-	memset(sh, 0, sizeof(*sh));
-	ArgArray_Init(&sh->builtins);
-
-	/*
-	 * Parse the specification by keyword but skip the first word
-	 */
-	brk_string(&aa, spec, TRUE);
-
-	for (arg = 1; arg < aa.argc; arg++) {
-		/*
-		 * Split keyword and value
-		 */
-		keyw = aa.argv[arg];
-		if ((eq = strchr(keyw, '=')) == NULL) {
-			Parse_Error(PARSE_FATAL, "missing '=' in shell "
-			    "specification keyword '%s'", keyw);
-			ArgArray_Done(&aa);
-			JobFreeShell(sh);
-			return (NULL);
-		}
-		*eq++ = '\0';
-
-		if (strcmp(keyw, "path") == 0) {
-			free(sh->path);
-			sh->path = estrdup(eq);
-		} else if (strcmp(keyw, "name") == 0) {
-			free(sh->name);
-			sh->name = estrdup(eq);
-		} else if (strcmp(keyw, "quiet") == 0) {
-			free(sh->echoOff);
-			sh->echoOff = estrdup(eq);
-			*fullSpec = TRUE;
-		} else if (strcmp(keyw, "echo") == 0) {
-			free(sh->echoOn);
-			sh->echoOn = estrdup(eq);
-			*fullSpec = TRUE;
-		} else if (strcmp(keyw, "filter") == 0) {
-			free(sh->noPrint);
-			sh->noPrint = estrdup(eq);
-			*fullSpec = TRUE;
-		} else if (strcmp(keyw, "echoFlag") == 0) {
-			free(sh->echo);
-			sh->echo = estrdup(eq);
-			*fullSpec = TRUE;
-		} else if (strcmp(keyw, "errFlag") == 0) {
-			free(sh->exit);
-			sh->exit = estrdup(eq);
-			*fullSpec = TRUE;
-		} else if (strcmp(keyw, "hasErrCtl") == 0) {
-			sh->hasErrCtl = (*eq == 'Y' || *eq == 'y' ||
-			    *eq == 'T' || *eq == 't');
-			*fullSpec = TRUE;
-		} else if (strcmp(keyw, "check") == 0) {
-			free(sh->errCheck);
-			sh->errCheck = estrdup(eq);
-			*fullSpec = TRUE;
-		} else if (strcmp(keyw, "ignore") == 0) {
-			free(sh->ignErr);
-			sh->ignErr = estrdup(eq);
-			*fullSpec = TRUE;
-		} else if (strcmp(keyw, "builtins") == 0) {
-			ArgArray_Done(&sh->builtins);
-			brk_string(&sh->builtins, eq, TRUE);
-			qsort(sh->builtins.argv + 1, sh->builtins.argc - 1,
-			    sizeof(char *), sort_builtins);
-			*fullSpec = TRUE;
-		} else if (strcmp(keyw, "meta") == 0) {
-			free(sh->meta);
-			sh->meta = estrdup(eq);
-			*fullSpec = TRUE;
-		} else if (strcmp(keyw, "unsetenv") == 0) {
-			sh->unsetenv = (*eq == 'Y' || *eq == 'y' ||
-			    *eq == 'T' || *eq == 't');
-			*fullSpec = TRUE;
-		} else {
-			Parse_Error(PARSE_FATAL, "unknown keyword in shell "
-			    "specification '%s'", keyw);
-			ArgArray_Done(&aa);
-			JobFreeShell(sh);
-			return (NULL);
-		}
-	}
-	ArgArray_Done(&aa);
-
-	/*
-	 * Some checks (could be more)
-	 */
-	if (*fullSpec) {
-		if ((sh->echoOn != NULL) ^ (sh->echoOff != NULL)) {
-			Parse_Error(PARSE_FATAL, "Shell must have either both "
-			    "echoOff and echoOn or none of them");
-			JobFreeShell(sh);
-			return (NULL);
-		}
-
-		if (sh->echoOn != NULL && sh->echoOff != NULL)
-			sh->hasEchoCtl = TRUE;
-	}
-
-	return (sh);
-}
-
-/**
- * Parse the builtin shell specifications and put them into the shell
- * list. Then select the default shell to be the current shell. This
- * is called from main() before any parsing (including MAKEFLAGS and
- * command line) is done.
- */
-void
-Shell_Init(void)
-{
-	int i;
-	struct Shell *sh;
-	Boolean fullSpec;
-
-	for (i = 0; shells_init[i] != NULL; i++) {
-		sh = JobParseShellSpec(shells_init[i], &fullSpec);
-		TAILQ_INSERT_TAIL(&shells, sh, link);
-		if (strcmp(sh->name, DEFSHELLNAME) == 0)
-			commandShell = sh;
-	}
-}
-
 /**
  * Job_Init
  *	Initialize the process module, given a maximum number of jobs.
@@ -2920,155 +2598,6 @@ Job_Empty(void)
 }
 
 /**
- * Find a matching shell in 'shells' given its final component.
- *
- * Results:
- *	A pointer to a freshly allocated Shell structure with the contents
- *	from static description or NULL if no shell with the given name
- *	is found.
- */
-static struct Shell *
-JobMatchShell(const char *name)
-{
-	struct Shell	*sh;
-
-	TAILQ_FOREACH(sh, &shells, link)
-		if (strcmp(sh->name, name) == 0)
-			return (sh);
-
-	return (NULL);
-}
-
-/**
- * Job_ParseShell
- *	Parse a shell specification and set up commandShell appropriately.
- *
- * Results:
- *	TRUE if the specification was correct. FALSE otherwise.
- *
- * Side Effects:
- *	commandShell points to a Shell structure (either predefined or
- *	created from the shell spec).
- *
- * Notes:
- *	A shell specification consists of a .SHELL target, with dependency
- *	operator, followed by a series of blank-separated words. Double
- *	quotes can be used to use blanks in words. A backslash escapes
- *	anything (most notably a double-quote and a space) and
- *	provides the functionality it does in C. Each word consists of
- *	keyword and value separated by an equal sign. There should be no
- *	unnecessary spaces in the word. The keywords are as follows:
- *	    name	    Name of shell.
- *	    path	    Location of shell. Overrides "name" if given
- *	    quiet	    Command to turn off echoing.
- *	    echo	    Command to turn echoing on
- *	    filter	    Result of turning off echoing that shouldn't be
- *			    printed.
- *	    echoFlag	    Flag to turn echoing on at the start
- *	    errFlag	    Flag to turn error checking on at the start
- *	    hasErrCtl	    True if shell has error checking control
- *	    check	    Command to turn on error checking if hasErrCtl
- *			    is TRUE or template of command to echo a command
- *			    for which error checking is off if hasErrCtl is
- *			    FALSE.
- *	    ignore	    Command to turn off error checking if hasErrCtl
- *			    is TRUE or template of command to execute a
- *			    command so as to ignore any errors it returns if
- *			    hasErrCtl is FALSE.
- *	    builtins	    A space separated list of builtins. If one
- *			    of these builtins is detected when make wants
- *			    to execute a command line, the command line is
- *			    handed to the shell. Otherwise make may try to
- *			    execute the command directly. If this list is empty
- *			    it is assumed, that the command must always be
- *			    handed over to the shell.
- *	    meta	    The shell meta characters. If this is not specified
- *			    or empty, commands are alway passed to the shell.
- *			    Otherwise they are not passed when they contain
- *			    neither a meta character nor a builtin command.
- */
-Boolean
-Job_ParseShell(const char line[])
-{
-	Boolean		fullSpec;
-	struct Shell	*sh;
-	struct Shell	*match;
-
-	/* parse the specification */
-	if ((sh = JobParseShellSpec(line, &fullSpec)) == NULL)
-		return (FALSE);
-
-	if (sh->path == NULL) {
-		/*
-		 * If no path was given, the user wants one of the pre-defined
-		 * shells, yes? So we find the one s/he wants with the help of
-		 * JobMatchShell and set things up the right way.
-		 */
-		if (sh->name == NULL) {
-			Parse_Error(PARSE_FATAL,
-			    "Neither path nor name specified");
-			JobFreeShell(sh);
-			return (FALSE);
-		}
-		if (fullSpec) {
-			Parse_Error(PARSE_FATAL, "No path specified");
-			JobFreeShell(sh);
-			return (FALSE);
-		}
-		if ((match = JobMatchShell(sh->name)) == NULL) {
-			Parse_Error(PARSE_FATAL, "%s: no matching shell",
-			    sh->name);
-			JobFreeShell(sh);
-			return (FALSE);
-		}
-		JobFreeShell(sh);
-		commandShell = match;
-
-		return (TRUE);
-	}
-
-	/*
-	 * The user provided a path. If s/he gave nothing else
-	 * (fullSpec is FALSE), try and find a matching shell in the
-	 * ones we know of. Else we just take the specification at its
-	 * word and copy it to a new location. In either case, we need
-	 * to record the path the user gave for the shell.
-	 */
-	if (sh->name == NULL) {
-		/* get the base name as the name */
-		if ((sh->name = strrchr(sh->path, '/')) == NULL) {
-			sh->name = estrdup(sh->path);
-		} else {
-			sh->name = estrdup(sh->name + 1);
-		}
-	}
-
-	if (!fullSpec) {
-		if ((match = JobMatchShell(sh->name)) == NULL) {
-			Parse_Error(PARSE_FATAL,
-			    "%s: no matching shell", sh->name);
-			JobFreeShell(sh);
-			return (FALSE);
-		}
-
-		/* set the patch on the matching shell */
-		free(match->path);
-		match->path = sh->path;
-		sh->path = NULL;
-
-		JobFreeShell(sh);
-		commandShell = match;
-		return (TRUE);
-	}
-
-	TAILQ_INSERT_HEAD(&shells, sh, link);
-
-	/* set the new shell */
-	commandShell = sh;
-	return (TRUE);
-}
-
-/**
  * JobInterrupt
  *	Handle the receipt of an interrupt.
  *
diff --git a/usr.bin/make/job.h b/usr.bin/make/job.h
index d479211..1ef4b66 100644
--- a/usr.bin/make/job.h
+++ b/usr.bin/make/job.h
@@ -64,15 +64,12 @@ void Job_Make(struct GNode *);
 void Job_Init(int);
 Boolean Job_Full(void);
 Boolean Job_Empty(void);
-Boolean Job_ParseShell(const char []);
 int Job_Finish(void);
 void Job_Wait(void);
 void Job_AbortAll(void);
 
 void Proc_Init(void);
 
-void Shell_Init(void);
-
 struct Buffer *Cmd_Exec(const char *, const char **);
 
 void Compat_Run(struct Lst *);
diff --git a/usr.bin/make/main.c b/usr.bin/make/main.c
index cbc2a30..f2eb77c 100644
--- a/usr.bin/make/main.c
+++ b/usr.bin/make/main.c
@@ -86,6 +86,7 @@ __FBSDID("$FreeBSD$");
 #include "make.h"
 #include "parse.h"
 #include "pathnames.h"
+#include "shell.h"
 #include "str.h"
 #include "suff.h"
 #include "targ.h"
diff --git a/usr.bin/make/parse.c b/usr.bin/make/parse.c
index 2f0a425..4d66103 100644
--- a/usr.bin/make/parse.c
+++ b/usr.bin/make/parse.c
@@ -90,6 +90,7 @@ __FBSDID("$FreeBSD$");
 #include "make.h"
 #include "parse.h"
 #include "pathnames.h"
+#include "shell.h"
 #include "str.h"
 #include "suff.h"
 #include "targ.h"
@@ -1087,7 +1088,7 @@ ParseDoDependency(char *line)
 		*line = '\0';
 
 	} else if (specType == ExShell) {
-		if (!Job_ParseShell(line)) {
+		if (!Shell_Parse(line)) {
 			Parse_Error(PARSE_FATAL,
 			    "improper shell specification");
 			return;
diff --git a/usr.bin/make/shell.c b/usr.bin/make/shell.c
new file mode 100644
index 0000000..c1f82d1
--- /dev/null
+++ b/usr.bin/make/shell.c
@@ -0,0 +1,472 @@
+/*-
+ * Copyright (c) 1988, 1989, 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 1988, 1989 by Adam de Boor
+ * Copyright (c) 1989 by Berkeley Softworks
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Adam de Boor.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/queue.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "parse.h"
+#include "pathnames.h"
+#include "shell.h"
+#include "util.h"
+
+/*
+ * Descriptions for various shells. What the list of builtins should contain
+ * is debatable: either all builtins or only those which may specified on
+ * a single line without use of meta-characters. For correct makefiles that
+ * contain only correct command lines there is no difference. But if a command
+ * line, for example, is: 'if -foo bar' and there is an executable named 'if'
+ * in the path, the first possibility would execute that 'if' while in the
+ * second case the shell would give an error. Histerically only a small
+ * subset of the builtins and no reserved words where given in the list which
+ * corresponds roughly to the first variant. So go with this but add missing
+ * words.
+ */
+#define	CSH_BUILTINS						\
+	"alias cd eval exec exit read set ulimit unalias "	\
+	"umask unset wait"
+
+#define	SH_BUILTINS						\
+	"alias cd eval exec exit read set ulimit unalias "	\
+	"umask unset wait"
+
+#define	CSH_META	"#=|^(){};&<>*?[]:$`\\@\n"
+#define	SH_META		"#=|^(){};&<>*?[]:$`\\\n"
+
+static const char *const shells_init[] = {
+	/*
+	 * CSH description. The csh can do echo control by playing
+	 * with the setting of the 'echo' shell variable. Sadly,
+	 * however, it is unable to do error control nicely.
+	 */
+	"name=csh path='" PATH_DEFSHELLDIR "/csh' "
+	"quiet='unset verbose' echo='set verbose' filter='unset verbose' "
+	"hasErrCtl=N check='echo \"%s\"\n' ignore='csh -c \"%s || exit 0\"' "
+	"echoFlag=v errFlag=e "
+	"meta='" CSH_META "' builtins='" CSH_BUILTINS "'",
+
+	/*
+	 * SH description. Echo control is also possible and, under
+	 * sun UNIX anyway, one can even control error checking.
+	 */
+	"name=sh path='" PATH_DEFSHELLDIR "/sh' "
+	"quiet='set -' echo='set -v' filter='set -' "
+	"hasErrCtl=Y check='set -e' ignore='set +e' "
+	"echoFlag=v errFlag=e "
+	"meta='" SH_META "' builtins='" SH_BUILTINS "'",
+
+	/*
+	 * KSH description. The Korn shell has a superset of
+	 * the Bourne shell's functionality. There are probably builtins
+	 * missing here.
+	 */
+	"name=ksh path='" PATH_DEFSHELLDIR "/ksh' "
+	"quiet='set -' echo='set -v' filter='set -' "
+	"hasErrCtl=Y check='set -e' ignore='set +e' "
+	"echoFlag=v errFlag=e "
+	"meta='" SH_META "' builtins='" SH_BUILTINS "' unsetenv=T",
+
+	NULL
+};
+
+/*
+ * This is the shell to which we pass all commands in the Makefile.
+ * It is set by the Job_ParseShell function.
+ */
+struct Shell *commandShell;
+
+/*
+ * This is the list of all known shells.
+ */
+static struct Shells shells = TAILQ_HEAD_INITIALIZER(shells);
+
+void ShellDump(const struct Shell *) __unused;
+
+/**
+ * Helper function for sorting the builtin list alphabetically.
+ */
+static int
+sort_builtins(const void *p1, const void *p2)
+{
+
+	return (strcmp(*(const char* const*)p1, *(const char* const*)p2));
+}
+
+/**
+ * Free a shell structure and all associated strings.
+ */
+static void
+ShellFree(struct Shell *sh)
+{
+
+	if (sh != NULL) {
+		free(sh->name);
+		free(sh->path);
+		free(sh->echoOff);
+		free(sh->echoOn);
+		free(sh->noPrint);
+		free(sh->errCheck);
+		free(sh->ignErr);
+		free(sh->echo);
+		free(sh->exit);
+		ArgArray_Done(&sh->builtins);
+		free(sh->meta);
+		free(sh);
+	}
+}
+
+/**
+ * Dump a shell specification to stderr.
+ */
+void
+ShellDump(const struct Shell *sh)
+{
+	int i;
+
+	fprintf(stderr, "Shell %p:\n", sh);
+	fprintf(stderr, "  name='%s' path='%s'\n", sh->name, sh->path);
+	fprintf(stderr, "  hasEchoCtl=%d echoOff='%s' echoOn='%s'\n",
+	    sh->hasEchoCtl, sh->echoOff, sh->echoOn);
+	fprintf(stderr, "  noPrint='%s'\n", sh->noPrint);
+	fprintf(stderr, "  hasErrCtl=%d errCheck='%s' ignErr='%s'\n",
+	    sh->hasErrCtl, sh->errCheck, sh->ignErr);
+	fprintf(stderr, "  echo='%s' exit='%s'\n", sh->echo, sh->exit);
+	fprintf(stderr, "  builtins=%d\n", sh->builtins.argc - 1);
+	for (i = 1; i < sh->builtins.argc; i++)
+		fprintf(stderr, " '%s'", sh->builtins.argv[i]);
+	fprintf(stderr, "\n  meta='%s'\n", sh->meta);
+	fprintf(stderr, "  unsetenv=%d\n", sh->unsetenv);
+}
+
+/**
+ * Parse a shell specification line and return the new Shell structure.
+ * In case of an error a message is printed and NULL is returned.
+ */
+static struct Shell *
+ShellParseSpec(const char *spec, Boolean *fullSpec)
+{
+	ArgArray	aa;
+	struct Shell	*sh;
+	char		*eq;
+	char		*keyw;
+	int		arg;
+
+	*fullSpec = FALSE;
+
+	sh = emalloc(sizeof(*sh));
+	memset(sh, 0, sizeof(*sh));
+	ArgArray_Init(&sh->builtins);
+
+	/*
+	 * Parse the specification by keyword but skip the first word
+	 */
+	brk_string(&aa, spec, TRUE);
+
+	for (arg = 1; arg < aa.argc; arg++) {
+		/*
+		 * Split keyword and value
+		 */
+		keyw = aa.argv[arg];
+		if ((eq = strchr(keyw, '=')) == NULL) {
+			Parse_Error(PARSE_FATAL, "missing '=' in shell "
+			    "specification keyword '%s'", keyw);
+			ArgArray_Done(&aa);
+			ShellFree(sh);
+			return (NULL);
+		}
+		*eq++ = '\0';
+
+		if (strcmp(keyw, "path") == 0) {
+			free(sh->path);
+			sh->path = estrdup(eq);
+		} else if (strcmp(keyw, "name") == 0) {
+			free(sh->name);
+			sh->name = estrdup(eq);
+		} else if (strcmp(keyw, "quiet") == 0) {
+			free(sh->echoOff);
+			sh->echoOff = estrdup(eq);
+			*fullSpec = TRUE;
+		} else if (strcmp(keyw, "echo") == 0) {
+			free(sh->echoOn);
+			sh->echoOn = estrdup(eq);
+			*fullSpec = TRUE;
+		} else if (strcmp(keyw, "filter") == 0) {
+			free(sh->noPrint);
+			sh->noPrint = estrdup(eq);
+			*fullSpec = TRUE;
+		} else if (strcmp(keyw, "echoFlag") == 0) {
+			free(sh->echo);
+			sh->echo = estrdup(eq);
+			*fullSpec = TRUE;
+		} else if (strcmp(keyw, "errFlag") == 0) {
+			free(sh->exit);
+			sh->exit = estrdup(eq);
+			*fullSpec = TRUE;
+		} else if (strcmp(keyw, "hasErrCtl") == 0) {
+			sh->hasErrCtl = (*eq == 'Y' || *eq == 'y' ||
+			    *eq == 'T' || *eq == 't');
+			*fullSpec = TRUE;
+		} else if (strcmp(keyw, "check") == 0) {
+			free(sh->errCheck);
+			sh->errCheck = estrdup(eq);
+			*fullSpec = TRUE;
+		} else if (strcmp(keyw, "ignore") == 0) {
+			free(sh->ignErr);
+			sh->ignErr = estrdup(eq);
+			*fullSpec = TRUE;
+		} else if (strcmp(keyw, "builtins") == 0) {
+			ArgArray_Done(&sh->builtins);
+			brk_string(&sh->builtins, eq, TRUE);
+			qsort(sh->builtins.argv + 1, sh->builtins.argc - 1,
+			    sizeof(char *), sort_builtins);
+			*fullSpec = TRUE;
+		} else if (strcmp(keyw, "meta") == 0) {
+			free(sh->meta);
+			sh->meta = estrdup(eq);
+			*fullSpec = TRUE;
+		} else if (strcmp(keyw, "unsetenv") == 0) {
+			sh->unsetenv = (*eq == 'Y' || *eq == 'y' ||
+			    *eq == 'T' || *eq == 't');
+			*fullSpec = TRUE;
+		} else {
+			Parse_Error(PARSE_FATAL, "unknown keyword in shell "
+			    "specification '%s'", keyw);
+			ArgArray_Done(&aa);
+			ShellFree(sh);
+			return (NULL);
+		}
+	}
+	ArgArray_Done(&aa);
+
+	/*
+	 * Some checks (could be more)
+	 */
+	if (*fullSpec) {
+		if ((sh->echoOn != NULL) ^ (sh->echoOff != NULL)) {
+			Parse_Error(PARSE_FATAL, "Shell must have either both "
+			    "echoOff and echoOn or none of them");
+			ShellFree(sh);
+			return (NULL);
+		}
+
+		if (sh->echoOn != NULL && sh->echoOff != NULL)
+			sh->hasEchoCtl = TRUE;
+	}
+
+	return (sh);
+}
+
+/**
+ * Parse the builtin shell specifications and put them into the shell
+ * list. Then select the default shell to be the current shell. This
+ * is called from main() before any parsing (including MAKEFLAGS and
+ * command line) is done.
+ */
+void
+Shell_Init(void)
+{
+	int i;
+	struct Shell *sh;
+	Boolean fullSpec;
+
+	for (i = 0; shells_init[i] != NULL; i++) {
+		sh = ShellParseSpec(shells_init[i], &fullSpec);
+		TAILQ_INSERT_TAIL(&shells, sh, link);
+		if (strcmp(sh->name, DEFSHELLNAME) == 0)
+			commandShell = sh;
+	}
+}
+
+/**
+ * Find a matching shell in 'shells' given its final component.
+ *
+ * Results:
+ *	A pointer to a freshly allocated Shell structure with the contents
+ *	from static description or NULL if no shell with the given name
+ *	is found.
+ */
+static struct Shell *
+ShellMatch(const char *name)
+{
+	struct Shell	*sh;
+
+	TAILQ_FOREACH(sh, &shells, link)
+		if (strcmp(sh->name, name) == 0)
+			return (sh);
+
+	return (NULL);
+}
+
+/**
+ * Parse a shell specification and set up commandShell appropriately.
+ *
+ * Results:
+ *	TRUE if the specification was correct. FALSE otherwise.
+ *
+ * Side Effects:
+ *	commandShell points to a Shell structure.
+ *	created from the shell spec).
+ *
+ * Notes:
+ *	A shell specification consists of a .SHELL target, with dependency
+ *	operator, followed by a series of blank-separated words. Double
+ *	quotes can be used to use blanks in words. A backslash escapes
+ *	anything (most notably a double-quote and a space) and
+ *	provides the functionality it does in C. Each word consists of
+ *	keyword and value separated by an equal sign. There should be no
+ *	unnecessary spaces in the word. The keywords are as follows:
+ *	    name	    Name of shell.
+ *	    path	    Location of shell. Overrides "name" if given
+ *	    quiet	    Command to turn off echoing.
+ *	    echo	    Command to turn echoing on
+ *	    filter	    Result of turning off echoing that shouldn't be
+ *			    printed.
+ *	    echoFlag	    Flag to turn echoing on at the start
+ *	    errFlag	    Flag to turn error checking on at the start
+ *	    hasErrCtl	    True if shell has error checking control
+ *	    check	    Command to turn on error checking if hasErrCtl
+ *			    is TRUE or template of command to echo a command
+ *			    for which error checking is off if hasErrCtl is
+ *			    FALSE.
+ *	    ignore	    Command to turn off error checking if hasErrCtl
+ *			    is TRUE or template of command to execute a
+ *			    command so as to ignore any errors it returns if
+ *			    hasErrCtl is FALSE.
+ *	    builtins	    A space separated list of builtins. If one
+ *			    of these builtins is detected when make wants
+ *			    to execute a command line, the command line is
+ *			    handed to the shell. Otherwise make may try to
+ *			    execute the command directly. If this list is empty
+ *			    it is assumed, that the command must always be
+ *			    handed over to the shell.
+ *	    meta	    The shell meta characters. If this is not specified
+ *			    or empty, commands are alway passed to the shell.
+ *			    Otherwise they are not passed when they contain
+ *			    neither a meta character nor a builtin command.
+ *	    unsetenv	    Unsetenv("ENV") before executing anything.
+ */
+Boolean
+Shell_Parse(const char line[])
+{
+	Boolean		fullSpec;
+	struct Shell	*sh;
+	struct Shell	*match;
+
+	/* parse the specification */
+	if ((sh = ShellParseSpec(line, &fullSpec)) == NULL)
+		return (FALSE);
+
+	if (sh->path == NULL) {
+		/*
+		 * If no path was given, the user wants one of the pre-defined
+		 * shells, yes? So we find the one s/he wants with the help of
+		 * JobMatchShell and set things up the right way.
+		 */
+		if (sh->name == NULL) {
+			Parse_Error(PARSE_FATAL,
+			    "Neither path nor name specified");
+			ShellFree(sh);
+			return (FALSE);
+		}
+		if (fullSpec) {
+			/*
+			 * XXX May want to merge sh into match. But this
+			 * require ShellParseSpec to return information
+			 * which attributes actuall have been specified.
+			 */
+			Parse_Error(PARSE_FATAL, "No path specified");
+			ShellFree(sh);
+			return (FALSE);
+		}
+		if ((match = ShellMatch(sh->name)) == NULL) {
+			Parse_Error(PARSE_FATAL, "%s: no matching shell",
+			    sh->name);
+			ShellFree(sh);
+			return (FALSE);
+		}
+		ShellFree(sh);
+		commandShell = match;
+
+		return (TRUE);
+	}
+
+	/*
+	 * The user provided a path. If s/he gave nothing else
+	 * (fullSpec is FALSE), try and find a matching shell in the
+	 * ones we know of. Else we just take the specification at its
+	 * word and copy it to a new location. In either case, we need
+	 * to record the path the user gave for the shell.
+	 */
+	if (sh->name == NULL) {
+		/* get the base name as the name */
+		if ((sh->name = strrchr(sh->path, '/')) == NULL) {
+			sh->name = estrdup(sh->path);
+		} else {
+			sh->name = estrdup(sh->name + 1);
+		}
+	}
+
+	if (!fullSpec) {
+		if ((match = ShellMatch(sh->name)) == NULL) {
+			Parse_Error(PARSE_FATAL,
+			    "%s: no matching shell", sh->name);
+			ShellFree(sh);
+			return (FALSE);
+		}
+
+		/* set the patch on the matching shell */
+		free(match->path);
+		match->path = sh->path;
+		sh->path = NULL;
+
+		ShellFree(sh);
+		commandShell = match;
+		return (TRUE);
+	}
+
+	TAILQ_INSERT_HEAD(&shells, sh, link);
+
+	/* set the new shell */
+	commandShell = sh;
+	return (TRUE);
+}
diff --git a/usr.bin/make/shell.h b/usr.bin/make/shell.h
new file mode 100644
index 0000000..a317058
--- /dev/null
+++ b/usr.bin/make/shell.h
@@ -0,0 +1,110 @@
+/*-
+ * Copyright (c) 1988, 1989, 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 1988, 1989 by Adam de Boor
+ * Copyright (c) 1989 by Berkeley Softworks
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Adam de Boor.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef shell_h_6002e3b8
+#define	shell_h_6002e3b8
+
+#include <sys/queue.h>
+
+#include "str.h"
+#include "util.h"
+
+/**
+ * Shell Specifications:
+ *
+ * Some special stuff goes on if a shell doesn't have error control. In such
+ * a case, errCheck becomes a printf template for echoing the command,
+ * should echoing be on and ignErr becomes another printf template for
+ * executing the command while ignoring the return status. If either of these
+ * strings is empty when hasErrCtl is FALSE, the command will be executed
+ * anyway as is and if it causes an error, so be it.
+ */
+struct Shell {
+	TAILQ_ENTRY(Shell) link;	/* link all shell descriptions */
+
+	/*
+	 * the name of the shell. For Bourne and C shells, this is used
+	 * only to find the shell description when used as the single
+	 * source of a .SHELL target.
+	 */
+	char	*name;
+
+	char	*path;		/* full path to the shell */
+
+	/* True if both echoOff and echoOn defined */
+	Boolean	hasEchoCtl;
+
+	char	*echoOff;	/* command to turn off echo */
+	char	*echoOn;	/* command to turn it back on */
+
+	/*
+	 * What the shell prints, and its length, when given the
+	 * echo-off command. This line will not be printed when
+	 * received from the shell. This is usually the command which
+	 * was executed to turn off echoing
+	 */
+	char	*noPrint;
+
+	/* set if can control error checking for individual commands */
+	Boolean	hasErrCtl;
+
+	/* string to turn error checking on */
+	char	*errCheck;
+
+	/* string to turn off error checking */
+	char	*ignErr;
+
+	char	*echo;	/* command line flag: echo commands */
+	char	*exit;	/* command line flag: exit on error */
+
+	ArgArray builtins;	/* ordered list of shell builtins */
+	char	*meta;		/* shell meta characters */
+
+	Boolean	unsetenv;	/* unsetenv("ENV") before exec */
+};
+TAILQ_HEAD(Shells, Shell);
+
+extern struct Shell		*commandShell;
+
+void				Shell_Init(void);
+Boolean				Shell_Parse(const char []);
+
+#endif /* shell_h_6002e3b8 */