xref: /src/usr.bin/make/parse.c

/*	$NetBSD: parse.c,v 1.365 2020/10/05 16:45:03 rillig Exp $	*/

/*
 * Copyright (c) 1988, 1989, 1990, 1993
 *	The Regents of the University of California.  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. 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.
 */

/*
 * 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.
 */

/*-
 * parse.c --
 *	Functions to parse a makefile.
 *
 *	One function, Parse_Init, must be called before any functions
 *	in this module are used. After that, the function Parse_File is the
 *	main entry point and controls most of the other functions in this
 *	module.
 *
 *	Most important structures are kept in Lsts. Directories for
 *	the .include "..." function are kept in the 'parseIncPath' Lst, while
 *	those for the .include <...> are kept in the 'sysIncPath' Lst. The
 *	targets currently being defined are kept in the 'targets' Lst.
 *
 *	The variables 'fname' and 'lineno' are used to track the name
 *	of the current file and the line number in that file so that error
 *	messages can be more meaningful.
 *
 * Interface:
 *	Parse_Init	Initialization function which must be
 *			called before anything else in this module
 *			is used.
 *
 *	Parse_End	Cleanup the module
 *
 *	Parse_File	Function used to parse a makefile. It must
 *			be given the name of the file, which should
 *			already have been opened, and a function
 *			to call to read a character from the file.
 *
 *	Parse_IsVar	Returns TRUE if the given line is a
 *			variable assignment. Used by MainParseArgs
 *			to determine if an argument is a target
 *			or a variable assignment. Used internally
 *			for pretty much the same thing...
 *
 *	Parse_Error	Function called when an error occurs in
 *			parsing. Used by the variable and
 *			conditional modules.
 *
 *	Parse_MainName	Returns a Lst of the main target to create.
 */

#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <errno.h>
#include <stdarg.h>
#include <stdint.h>

#ifndef MAP_FILE
#define MAP_FILE 0
#endif
#ifndef MAP_COPY
#define MAP_COPY MAP_PRIVATE
#endif

#include "make.h"
#include "dir.h"
#include "job.h"
#include "pathnames.h"

/*	"@(#)parse.c	8.3 (Berkeley) 3/19/94"	*/
MAKE_RCSID("$NetBSD: parse.c,v 1.365 2020/10/05 16:45:03 rillig Exp $");

/* types and constants */

/*
 * Structure for a file being read ("included file")
 */
typedef struct IFile {
    char *fname;		/* name of file */
    Boolean fromForLoop;	/* simulated .include by the .for loop */
    int lineno;			/* current line number in file */
    int first_lineno;		/* line number of start of text */
    int cond_depth;		/* 'if' nesting when file opened */
    Boolean depending;		/* state of doing_depend on EOF */
    char *P_str;		/* point to base of string buffer */
    char *P_ptr;		/* point to next char of string buffer */
    char *P_end;		/* point to the end of string buffer */
    char *(*nextbuf)(void *, size_t *); /* Function to get more data */
    void *nextbuf_arg;		/* Opaque arg for nextbuf() */
    struct loadedfile *lf;	/* loadedfile object, if any */
} IFile;


/*
 * These values are returned by ParseEOF to tell Parse_File whether to
 * CONTINUE parsing, i.e. it had only reached the end of an include file,
 * or if it's DONE.
 */
#define CONTINUE	1
#define DONE		0

/*
 * Tokens for target attributes
 */
typedef enum {
    Begin,		/* .BEGIN */
    Default,		/* .DEFAULT */
    DeleteOnError,	/* .DELETE_ON_ERROR */
    End,		/* .END */
    dotError,		/* .ERROR */
    Ignore,		/* .IGNORE */
    Includes,		/* .INCLUDES */
    Interrupt,		/* .INTERRUPT */
    Libs,		/* .LIBS */
    Meta,		/* .META */
    MFlags,		/* .MFLAGS or .MAKEFLAGS */
    Main,		/* .MAIN and we don't have anything user-specified to
			 * make */
    NoExport,		/* .NOEXPORT */
    NoMeta,		/* .NOMETA */
    NoMetaCmp,		/* .NOMETA_CMP */
    NoPath,		/* .NOPATH */
    Not,		/* Not special */
    NotParallel,	/* .NOTPARALLEL */
    Null,		/* .NULL */
    ExObjdir,		/* .OBJDIR */
    Order,		/* .ORDER */
    Parallel,		/* .PARALLEL */
    ExPath,		/* .PATH */
    Phony,		/* .PHONY */
#ifdef POSIX
    Posix,		/* .POSIX */
#endif
    Precious,		/* .PRECIOUS */
    ExShell,		/* .SHELL */
    Silent,		/* .SILENT */
    SingleShell,	/* .SINGLESHELL */
    Stale,		/* .STALE */
    Suffixes,		/* .SUFFIXES */
    Wait,		/* .WAIT */
    Attribute		/* Generic attribute */
} ParseSpecial;

typedef List SearchPathList;

/* result data */

/*
 * The main target to create. This is the first target on the first
 * dependency line in the first makefile.
 */
static GNode *mainNode;

/* eval state */

/* During parsing, the targets from the currently active dependency line,
 * or NULL if the current line does not belong to a dependency line, for
 * example because it is a variable assignment.
 *
 * See unit-tests/deptgt.mk, keyword "parse.c:targets". */
static GNodeList *targets;

#ifdef CLEANUP
/* command lines for targets */
static StringList *targCmds;
#endif

/*
 * Predecessor node for handling .ORDER. Initialized to NULL when .ORDER
 * seen, then set to each successive source on the line.
 */
static GNode	*predecessor;

/* parser state */

/* number of fatal errors */
static int fatals = 0;

/*
 * Variables for doing includes
 */

/* current file being read */
static IFile *curFile;

/* The include chain of makefiles that leads to curFile.  At the bottom of
 * the stack is the top-level makefile from the command line, and on top of
 * this file, there are the included files or .for loops, up to but excluding
 * curFile.
 *
 * This data could be used to print stack traces on parse errors.  As of
 * 2020-09-14, this is not done though.  It seems quite simple to print the
 * tuples (fname:lineno:fromForLoop), from top to bottom.  This simple idea is
 * made complicated by the fact that the .for loops also use this stack for
 * storing information.
 *
 * The lineno fields of the IFiles with fromForLoop == TRUE look confusing,
 * which is demonstrated by the test 'include-main.mk'.  They seem sorted
 * backwards since they tell the number of completely parsed lines, which for
 * a .for loop is right after the terminating .endfor.  To compensate for this
 * confusion, there is another field first_lineno pointing at the start of the
 * .for loop, 1-based for human consumption.
 *
 * To make the stack trace intuitive, the entry below the first .for loop must
 * be ignored completely since neither its lineno nor its first_lineno is
 * useful.  Instead, the topmost .for loop needs to be printed twice, once
 * with its first_lineno and once with its lineno.
 *
 * As of 2020-09-15, using the above rules, the stack trace for the .info line
 * in include-subsub.mk would be:
 *
 *	curFile:	include-subsub.mk:4
 *			(lineno, from an .include)
 *	includes[4]:	include-sub.mk:32
 *			(lineno, from a .for loop below an .include)
 *	includes[4]:	include-sub.mk:31
 *			(first_lineno, from a .for loop, lineno == 32)
 *	includes[3]:	include-sub.mk:30
 *			(first_lineno, from a .for loop, lineno == 33)
 *	includes[2]:	include-sub.mk:29
 *			(first_lineno, from a .for loop, lineno == 34)
 *	includes[1]:	include-sub.mk:35
 *			(not printed since it is below a .for loop)
 *	includes[0]:	include-main.mk:27
 */
static Stack /* of *IFile */ includes;

/* include paths (lists of directories) */
SearchPath *parseIncPath;	/* dirs for "..." includes */
SearchPath *sysIncPath;		/* dirs for <...> includes */
SearchPath *defIncPath;		/* default for sysIncPath */

/* parser tables */

/*
 * The parseKeywords table is searched using binary search when deciding
 * if a target or source is special. The 'spec' field is the ParseSpecial
 * type of the keyword ("Not" if the keyword isn't special as a target) while
 * the 'op' field is the operator to apply to the list of targets if the
 * keyword is used as a source ("0" if the keyword isn't special as a source)
 */
static const struct {
    const char   *name;		/* Name of keyword */
    ParseSpecial  spec;		/* Type when used as a target */
    GNodeType	  op;		/* Operator when used as a source */
} parseKeywords[] = {
    { ".BEGIN",		Begin,		0 },
    { ".DEFAULT",	Default,	0 },
    { ".DELETE_ON_ERROR", DeleteOnError, 0 },
    { ".END",		End,		0 },
    { ".ERROR",		dotError,	0 },
    { ".EXEC",		Attribute,	OP_EXEC },
    { ".IGNORE",	Ignore,		OP_IGNORE },
    { ".INCLUDES",	Includes,	0 },
    { ".INTERRUPT",	Interrupt,	0 },
    { ".INVISIBLE",	Attribute,	OP_INVISIBLE },
    { ".JOIN",		Attribute,	OP_JOIN },
    { ".LIBS",		Libs,		0 },
    { ".MADE",		Attribute,	OP_MADE },
    { ".MAIN",		Main,		0 },
    { ".MAKE",		Attribute,	OP_MAKE },
    { ".MAKEFLAGS",	MFlags,		0 },
    { ".META",		Meta,		OP_META },
    { ".MFLAGS",	MFlags,		0 },
    { ".NOMETA",	NoMeta,		OP_NOMETA },
    { ".NOMETA_CMP",	NoMetaCmp,	OP_NOMETA_CMP },
    { ".NOPATH",	NoPath,		OP_NOPATH },
    { ".NOTMAIN",	Attribute,	OP_NOTMAIN },
    { ".NOTPARALLEL",	NotParallel,	0 },
    { ".NO_PARALLEL",	NotParallel,	0 },
    { ".NULL",		Null,		0 },
    { ".OBJDIR",	ExObjdir,	0 },
    { ".OPTIONAL",	Attribute,	OP_OPTIONAL },
    { ".ORDER",		Order,		0 },
    { ".PARALLEL",	Parallel,	0 },
    { ".PATH",		ExPath,		0 },
    { ".PHONY",		Phony,		OP_PHONY },
#ifdef POSIX
    { ".POSIX",		Posix,		0 },
#endif
    { ".PRECIOUS",	Precious,	OP_PRECIOUS },
    { ".RECURSIVE",	Attribute,	OP_MAKE },
    { ".SHELL",		ExShell,	0 },
    { ".SILENT",	Silent,		OP_SILENT },
    { ".SINGLESHELL",	SingleShell,	0 },
    { ".STALE",		Stale,		0 },
    { ".SUFFIXES",	Suffixes,	0 },
    { ".USE",		Attribute,	OP_USE },
    { ".USEBEFORE",	Attribute,	OP_USEBEFORE },
    { ".WAIT",		Wait,		0 },
};

/* file loader */

struct loadedfile {
	const char *path;		/* name, for error reports */
	char *buf;			/* contents buffer */
	size_t len;			/* length of contents */
	size_t maplen;			/* length of mmap area, or 0 */
	Boolean used;			/* XXX: have we used the data yet */
};

static struct loadedfile *
loadedfile_create(const char *path)
{
	struct loadedfile *lf;

	lf = bmake_malloc(sizeof(*lf));
	lf->path = path == NULL ? "(stdin)" : path;
	lf->buf = NULL;
	lf->len = 0;
	lf->maplen = 0;
	lf->used = FALSE;
	return lf;
}

static void
loadedfile_destroy(struct loadedfile *lf)
{
	if (lf->buf != NULL) {
		if (lf->maplen > 0) {
			munmap(lf->buf, lf->maplen);
		} else {
			free(lf->buf);
		}
	}
	free(lf);
}

/*
 * nextbuf() operation for loadedfile, as needed by the weird and twisted
 * logic below. Once that's cleaned up, we can get rid of lf->used...
 */
static char *
loadedfile_nextbuf(void *x, size_t *len)
{
	struct loadedfile *lf = x;

	if (lf->used) {
		return NULL;
	}
	lf->used = TRUE;
	*len = lf->len;
	return lf->buf;
}

/*
 * Try to get the size of a file.
 */
static Boolean
load_getsize(int fd, size_t *ret)
{
	struct stat st;

	if (fstat(fd, &st) < 0) {
		return FALSE;
	}

	if (!S_ISREG(st.st_mode)) {
		return FALSE;
	}

	/*
	 * st_size is an off_t, which is 64 bits signed; *ret is
	 * size_t, which might be 32 bits unsigned or 64 bits
	 * unsigned. Rather than being elaborate, just punt on
	 * files that are more than 2^31 bytes. We should never
	 * see a makefile that size in practice...
	 *
	 * While we're at it reject negative sizes too, just in case.
	 */
	if (st.st_size < 0 || st.st_size > 0x7fffffff) {
		return FALSE;
	}

	*ret = (size_t) st.st_size;
	return TRUE;
}

/*
 * Read in a file.
 *
 * Until the path search logic can be moved under here instead of
 * being in the caller in another source file, we need to have the fd
 * passed in already open. Bleh.
 *
 * If the path is NULL use stdin and (to insure against fd leaks)
 * assert that the caller passed in -1.
 */
static struct loadedfile *
loadfile(const char *path, int fd)
{
	struct loadedfile *lf;
	static long pagesize = 0;
	ssize_t result;
	size_t bufpos;

	lf = loadedfile_create(path);

	if (path == NULL) {
		assert(fd == -1);
		fd = STDIN_FILENO;
	} else {
#if 0 /* notyet */
		fd = open(path, O_RDONLY);
		if (fd < 0) {
			...
			Error("%s: %s", path, strerror(errno));
			exit(1);
		}
#endif
	}

	if (load_getsize(fd, &lf->len)) {
		/* found a size, try mmap */
		if (pagesize == 0)
			pagesize = sysconf(_SC_PAGESIZE);
		if (pagesize <= 0) {
			pagesize = 0x1000;
		}
		/* round size up to a page */
		lf->maplen = pagesize * ((lf->len + pagesize - 1)/pagesize);

		/*
		 * XXX hack for dealing with empty files; remove when
		 * we're no longer limited by interfacing to the old
		 * logic elsewhere in this file.
		 */
		if (lf->maplen == 0) {
			lf->maplen = pagesize;
		}

		/*
		 * FUTURE: remove PROT_WRITE when the parser no longer
		 * needs to scribble on the input.
		 */
		lf->buf = mmap(NULL, lf->maplen, PROT_READ|PROT_WRITE,
			       MAP_FILE|MAP_COPY, fd, 0);
		if (lf->buf != MAP_FAILED) {
			/* succeeded */
			if (lf->len == lf->maplen && lf->buf[lf->len - 1] != '\n') {
				char *b = bmake_malloc(lf->len + 1);
				b[lf->len] = '\n';
				memcpy(b, lf->buf, lf->len++);
				munmap(lf->buf, lf->maplen);
				lf->maplen = 0;
				lf->buf = b;
			}
			goto done;
		}
	}

	/* cannot mmap; load the traditional way */

	lf->maplen = 0;
	lf->len = 1024;
	lf->buf = bmake_malloc(lf->len);

	bufpos = 0;
	while (1) {
		assert(bufpos <= lf->len);
		if (bufpos == lf->len) {
			if (lf->len > SIZE_MAX/2) {
				errno = EFBIG;
				Error("%s: file too large", path);
				exit(1);
			}
			lf->len *= 2;
			lf->buf = bmake_realloc(lf->buf, lf->len);
		}
		assert(bufpos < lf->len);
		result = read(fd, lf->buf + bufpos, lf->len - bufpos);
		if (result < 0) {
			Error("%s: read error: %s", path, strerror(errno));
			exit(1);
		}
		if (result == 0) {
			break;
		}
		bufpos += result;
	}
	assert(bufpos <= lf->len);
	lf->len = bufpos;

	/* truncate malloc region to actual length (maybe not useful) */
	if (lf->len > 0) {
		/* as for mmap case, ensure trailing \n */
		if (lf->buf[lf->len - 1] != '\n')
			lf->len++;
		lf->buf = bmake_realloc(lf->buf, lf->len);
		lf->buf[lf->len - 1] = '\n';
	}

done:
	if (path != NULL) {
		close(fd);
	}
	return lf;
}

/* old code */

/* Check if the current character is escaped on the current line. */
static Boolean
ParseIsEscaped(const char *line, const char *c)
{
    Boolean active = FALSE;
    for (;;) {
	if (line == c)
	    return active;
	if (*--c != '\\')
	    return active;
	active = !active;
    }
}

/* Add the filename and lineno to the GNode so that we remember where it
 * was first defined. */
static void
ParseMark(GNode *gn)
{
    gn->fname = curFile->fname;
    gn->lineno = curFile->lineno;
}

/* Look in the table of keywords for one matching the given string.
 * Return the index of the keyword, or -1 if it isn't there. */
static int
ParseFindKeyword(const char *str)
{
    int    start, end, cur;
    int    diff;

    start = 0;
    end = (sizeof(parseKeywords)/sizeof(parseKeywords[0])) - 1;

    do {
	cur = start + ((end - start) / 2);
	diff = strcmp(str, parseKeywords[cur].name);

	if (diff == 0) {
	    return cur;
	} else if (diff < 0) {
	    end = cur - 1;
	} else {
	    start = cur + 1;
	}
    } while (start <= end);
    return -1;
}

static void
PrintLocation(FILE *f, const char *filename, size_t lineno)
{
	char dirbuf[MAXPATHLEN+1];
	const char *dir, *base;
	char *dir_freeIt, *base_freeIt;

	if (*filename == '/' || strcmp(filename, "(stdin)") == 0) {
		(void)fprintf(f, "\"%s\" line %zu: ", filename, lineno);
		return;
	}

	/* Find out which makefile is the culprit.
	 * We try ${.PARSEDIR} and apply realpath(3) if not absolute. */

	dir = Var_Value(".PARSEDIR", VAR_GLOBAL, &dir_freeIt);
	if (dir == NULL)
		dir = ".";
	if (*dir != '/')
		dir = realpath(dir, dirbuf);

	base = Var_Value(".PARSEFILE", VAR_GLOBAL, &base_freeIt);
	if (base == NULL) {
		const char *slash = strrchr(filename, '/');
		base = slash != NULL ? slash + 1 : filename;
	}

	(void)fprintf(f, "\"%s/%s\" line %zu: ", dir, base, lineno);
	bmake_free(base_freeIt);
	bmake_free(dir_freeIt);
}

/* Print a parse error message, including location information.
 *
 * Increment "fatals" if the level is PARSE_FATAL, and continue parsing
 * until the end of the current top-level makefile, then exit (see
 * Parse_File). */
static void
ParseVErrorInternal(FILE *f, const char *cfname, size_t clineno, int type,
    const char *fmt, va_list ap)
{
	static Boolean fatal_warning_error_printed = FALSE;

	(void)fprintf(f, "%s: ", progname);

	if (cfname != NULL)
		PrintLocation(f, cfname, clineno);
	if (type == PARSE_WARNING)
		(void)fprintf(f, "warning: ");
	(void)vfprintf(f, fmt, ap);
	(void)fprintf(f, "\n");
	(void)fflush(f);

	if (type == PARSE_INFO)
		return;
	if (type == PARSE_FATAL || parseWarnFatal)
		fatals++;
	if (parseWarnFatal && !fatal_warning_error_printed) {
		Error("parsing warnings being treated as errors");
		fatal_warning_error_printed = TRUE;
	}
}

static void
ParseErrorInternal(const char *cfname, size_t clineno, int type,
    const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	(void)fflush(stdout);
	ParseVErrorInternal(stderr, cfname, clineno, type, fmt, ap);
	va_end(ap);

	if (debug_file != stderr && debug_file != stdout) {
		va_start(ap, fmt);
		ParseVErrorInternal(debug_file, cfname, clineno, type, fmt, ap);
		va_end(ap);
	}
}

/* External interface to ParseErrorInternal; uses the default filename and
 * line number.
 *
 * Fmt is given without a trailing newline. */
void
Parse_Error(int type, const char *fmt, ...)
{
	va_list ap;
	const char *fname;
	size_t lineno;

	if (curFile == NULL) {
		fname = NULL;
		lineno = 0;
	} else {
		fname = curFile->fname;
		lineno = curFile->lineno;
	}

	va_start(ap, fmt);
	(void)fflush(stdout);
	ParseVErrorInternal(stderr, fname, lineno, type, fmt, ap);
	va_end(ap);

	if (debug_file != stderr && debug_file != stdout) {
		va_start(ap, fmt);
		ParseVErrorInternal(debug_file, fname, lineno, type, fmt, ap);
		va_end(ap);
	}
}


/* Parse a .info .warning or .error directive.
 *
 * The input is the line minus the ".".  We substitute variables, print the
 * message and exit(1) (for .error) or just print a warning if the directive
 * is malformed.
 */
static Boolean
ParseMessage(char *line)
{
    int mtype;

    switch(*line) {
    case 'i':
	mtype = PARSE_INFO;
	break;
    case 'w':
	mtype = PARSE_WARNING;
	break;
    case 'e':
	mtype = PARSE_FATAL;
	break;
    default:
	Parse_Error(PARSE_WARNING, "invalid syntax: \".%s\"", line);
	return FALSE;
    }

    while (ch_isalpha(*line))
	line++;
    if (!ch_isspace(*line))
	return FALSE;			/* not for us */
    pp_skip_whitespace(&line);

    (void)Var_Subst(line, VAR_CMD, VARE_WANTRES, &line);
    /* TODO: handle errors */
    Parse_Error(mtype, "%s", line);
    free(line);

    if (mtype == PARSE_FATAL) {
	/* Terminate almost immediately. */
	PrintOnError(NULL, NULL);
	exit(1);
    }
    return TRUE;
}

struct ParseLinkSrcArgs {
    GNode *cgn;

    /* The special target of the current dependency line. */
    /* Example: for ".END: action", it is 'End'. */
    ParseSpecial specType;
};

/* Add the child to the parent's children.
 *
 * Add the parent to the child's parents, but only if the target is not
 * special.  An example for such a special target is .END, which does not
 * need to be informed once the child target has been made. */
static void
ParseLinkSrc(void *pgnp, void *data)
{
    const struct ParseLinkSrcArgs *args = data;
    GNode *pgn = pgnp;
    GNode *cgn = args->cgn;

    if ((pgn->type & OP_DOUBLEDEP) && !Lst_IsEmpty(pgn->cohorts))
	pgn = LstNode_Datum(Lst_Last(pgn->cohorts));

    Lst_Append(pgn->children, cgn);
    pgn->unmade++;

    if (args->specType == Not)
	Lst_Append(cgn->parents, pgn);

    if (DEBUG(PARSE)) {
	debug_printf("# %s: added child %s - %s\n",
		     __func__, pgn->name, cgn->name);
	Targ_PrintNode(pgn, 0);
	Targ_PrintNode(cgn, 0);
    }
}

static Boolean
TryApplyDependencyOperator(GNode *gn, GNodeType op)
{
    /*
     * If the dependency mask of the operator and the node don't match and
     * the node has actually had an operator applied to it before, and
     * the operator actually has some dependency information in it, complain.
     */
    if (((op & OP_OPMASK) != (gn->type & OP_OPMASK)) &&
	!OP_NOP(gn->type) && !OP_NOP(op))
    {
	Parse_Error(PARSE_FATAL, "Inconsistent operator for %s", gn->name);
	return FALSE;
    }

    if (op == OP_DOUBLEDEP && (gn->type & OP_OPMASK) == OP_DOUBLEDEP) {
	/*
	 * If the node was the object of a :: operator, we need to create a
	 * new instance of it for the children and commands on this dependency
	 * line. The new instance is placed on the 'cohorts' list of the
	 * initial one (note the initial one is not on its own cohorts list)
	 * and the new instance is linked to all parents of the initial
	 * instance.
	 */
	GNode	*cohort;

	/*
	 * Propagate copied bits to the initial node.  They'll be propagated
	 * back to the rest of the cohorts later.
	 */
	gn->type |= op & ~OP_OPMASK;

	cohort = Targ_NewInternalNode(gn->name);
	if (doing_depend)
	    ParseMark(cohort);
	/*
	 * Make the cohort invisible as well to avoid duplicating it into
	 * other variables. True, parents of this target won't tend to do
	 * anything with their local variables, but better safe than
	 * sorry. (I think this is pointless now, since the relevant list
	 * traversals will no longer see this node anyway. -mycroft)
	 */
	cohort->type = op | OP_INVISIBLE;
	Lst_Append(gn->cohorts, cohort);
	cohort->centurion = gn;
	gn->unmade_cohorts++;
	snprintf(cohort->cohort_num, sizeof cohort->cohort_num, "#%d",
		gn->unmade_cohorts);
    } else {
	/*
	 * We don't want to nuke any previous flags (whatever they were) so we
	 * just OR the new operator into the old
	 */
	gn->type |= op;
    }

    return TRUE;
}

static void
ApplyDependencyOperator(GNodeType op)
{
    GNodeListNode *ln;
    for (ln = targets->first; ln != NULL; ln = ln->next)
        if (!TryApplyDependencyOperator(ln->datum, op))
	    break;
}

static Boolean
ParseDoSrcKeyword(const char *src, ParseSpecial specType)
{
    static int wait_number = 0;
    char wait_src[16];
    GNode *gn;

    if (*src == '.' && ch_isupper(src[1])) {
	int keywd = ParseFindKeyword(src);
	if (keywd != -1) {
	    int op = parseKeywords[keywd].op;
	    if (op != 0) {
		ApplyDependencyOperator(op);
		return TRUE;
	    }
	    if (parseKeywords[keywd].spec == Wait) {
		/*
		 * We add a .WAIT node in the dependency list.
		 * After any dynamic dependencies (and filename globbing)
		 * have happened, it is given a dependency on the each
		 * previous child back to and previous .WAIT node.
		 * The next child won't be scheduled until the .WAIT node
		 * is built.
		 * We give each .WAIT node a unique name (mainly for diag).
		 */
		snprintf(wait_src, sizeof wait_src, ".WAIT_%u", ++wait_number);
		gn = Targ_NewInternalNode(wait_src);
		if (doing_depend)
		    ParseMark(gn);
		gn->type = OP_WAIT | OP_PHONY | OP_DEPENDS | OP_NOTMAIN;
		{
		    struct ParseLinkSrcArgs args = { gn, specType };
		    Lst_ForEach(targets, ParseLinkSrc, &args);
		}
		return TRUE;
	    }
	}
    }
    return FALSE;
}

static void
ParseDoSrcMain(const char *src)
{
    /*
     * If we have noted the existence of a .MAIN, it means we need
     * to add the sources of said target to the list of things
     * to create. The string 'src' is likely to be free, so we
     * must make a new copy of it. Note that this will only be
     * invoked if the user didn't specify a target on the command
     * line. This is to allow #ifmake's to succeed, or something...
     */
    Lst_Append(create, bmake_strdup(src));
    /*
     * Add the name to the .TARGETS variable as well, so the user can
     * employ that, if desired.
     */
    Var_Append(".TARGETS", src, VAR_GLOBAL);
}

static void
ParseDoSrcOrder(const char *src)
{
    GNode *gn;
    /*
     * Create proper predecessor/successor links between the previous
     * source and the current one.
     */
    gn = Targ_GetNode(src);
    if (doing_depend)
	ParseMark(gn);
    if (predecessor != NULL) {
	Lst_Append(predecessor->order_succ, gn);
	Lst_Append(gn->order_pred, predecessor);
	if (DEBUG(PARSE)) {
	    debug_printf("# %s: added Order dependency %s - %s\n",
			 __func__, predecessor->name, gn->name);
	    Targ_PrintNode(predecessor, 0);
	    Targ_PrintNode(gn, 0);
	}
    }
    /*
     * The current source now becomes the predecessor for the next one.
     */
    predecessor = gn;
}

static void
ParseDoSrcOther(const char *src, GNodeType tOp, ParseSpecial specType)
{
    GNode *gn;

    /*
     * If the source is not an attribute, we need to find/create
     * a node for it. After that we can apply any operator to it
     * from a special target or link it to its parents, as
     * appropriate.
     *
     * In the case of a source that was the object of a :: operator,
     * the attribute is applied to all of its instances (as kept in
     * the 'cohorts' list of the node) or all the cohorts are linked
     * to all the targets.
     */

    /* Find/create the 'src' node and attach to all targets */
    gn = Targ_GetNode(src);
    if (doing_depend)
	ParseMark(gn);
    if (tOp) {
	gn->type |= tOp;
    } else {
	{
	    struct ParseLinkSrcArgs args = { gn, specType };
	    Lst_ForEach(targets, ParseLinkSrc, &args);
	}
    }
}

/* Given the name of a source in a dependency line, figure out if it is an
 * attribute (such as .SILENT) and apply it to the targets if it is. Else
 * decide if there is some attribute which should be applied *to* the source
 * because of some special target (such as .PHONY) and apply it if so.
 * Otherwise, make the source a child of the targets in the list 'targets'.
 *
 * Input:
 *	tOp		operator (if any) from special targets
 *	src		name of the source to handle
 */
static void
ParseDoSrc(GNodeType tOp, const char *src, ParseSpecial specType)
{
    if (ParseDoSrcKeyword(src, specType))
        return;

    if (specType == Main)
        ParseDoSrcMain(src);
    else if (specType == Order)
        ParseDoSrcOrder(src);
    else
        ParseDoSrcOther(src, tOp, specType);
}

/* If we have yet to decide on a main target to make, in the absence of any
 * user input, we want the first target on the first dependency line that is
 * actually a real target (i.e. isn't a .USE or .EXEC rule) to be made. */
static void
FindMainTarget(void)
{
    GNodeListNode *ln;

    if (mainNode != NULL)
        return;

    for (ln = targets->first; ln != NULL; ln = ln->next) {
	GNode *gn = ln->datum;
	if (!(gn->type & OP_NOTARGET)) {
	    mainNode = gn;
	    Targ_SetMain(gn);
	    return;
	}
    }
}

static void
ParseAddDir(void *path, void *name)
{
    (void)Dir_AddDir(path, name);
}

static void
ParseClearPath(void *path, void *unused MAKE_ATTR_UNUSED)
{
    Dir_ClearPath(path);
}

/*
 * We got to the end of the line while we were still looking at targets.
 *
 * Ending a dependency line without an operator is a Bozo no-no.  As a
 * heuristic, this is also often triggered by undetected conflicts from
 * cvs/rcs merges.
 */
static void
ParseErrorNoDependency(const char *lstart, const char *line)
{
    if ((strncmp(line, "<<<<<<", 6) == 0) ||
	(strncmp(line, "======", 6) == 0) ||
	(strncmp(line, ">>>>>>", 6) == 0))
	Parse_Error(PARSE_FATAL,
		    "Makefile appears to contain unresolved cvs/rcs/??? merge conflicts");
    else if (lstart[0] == '.') {
	const char *dirstart = lstart + 1;
	const char *dirend;
	cpp_skip_whitespace(&dirstart);
	dirend = dirstart;
	while (ch_isalnum(*dirend) || *dirend == '-')
	    dirend++;
	Parse_Error(PARSE_FATAL, "Unknown directive \"%.*s\"",
		    (int)(dirend - dirstart), dirstart);
    } else
	Parse_Error(PARSE_FATAL, "Need an operator");
}

static void
ParseDependencyTargetWord(/*const*/ char **pp, const char *lstart)
{
    /*const*/ char *cp = *pp;

    while (*cp != '\0') {
	if ((ch_isspace(*cp) || *cp == '!' || *cp == ':' || *cp == '(') &&
	    !ParseIsEscaped(lstart, cp))
	    break;

	if (*cp == '$') {
	    /*
	     * Must be a dynamic source (would have been expanded
	     * otherwise), so call the Var module to parse the puppy
	     * so we can safely advance beyond it...There should be
	     * no errors in this, as they would have been discovered
	     * in the initial Var_Subst and we wouldn't be here.
	     */
	    const char *nested_p = cp;
	    const char *nested_val;
	    void    *freeIt;

	    (void)Var_Parse(&nested_p, VAR_CMD, VARE_UNDEFERR|VARE_WANTRES,
			    &nested_val, &freeIt);
	    /* TODO: handle errors */
	    free(freeIt);
	    cp += nested_p - cp;
	} else
	    cp++;
    }

    *pp = cp;
}

/*
 * Certain special targets have special semantics:
 *	.PATH		Have to set the dirSearchPath
 *			variable too
 *	.MAIN		Its sources are only used if
 *			nothing has been specified to
 *			create.
 *	.DEFAULT	Need to create a node to hang
 *			commands on, but we don't want
 *			it in the graph, nor do we want
 *			it to be the Main Target, so we
 *			create it, set OP_NOTMAIN and
 *			add it to the list, setting
 *			DEFAULT to the new node for
 *			later use. We claim the node is
 *			A transformation rule to make
 *			life easier later, when we'll
 *			use Make_HandleUse to actually
 *			apply the .DEFAULT commands.
 *	.PHONY		The list of targets
 *	.NOPATH		Don't search for file in the path
 *	.STALE
 *	.BEGIN
 *	.END
 *	.ERROR
 *	.DELETE_ON_ERROR
 *	.INTERRUPT	Are not to be considered the
 *			main target.
 *	.NOTPARALLEL	Make only one target at a time.
 *	.SINGLESHELL	Create a shell for each command.
 *	.ORDER		Must set initial predecessor to NULL
 */
static void
ParseDoDependencyTargetSpecial(ParseSpecial *const inout_specType,
			       const char *const line,
			       SearchPathList **const inout_paths)
{
    switch (*inout_specType) {
    case ExPath:
	if (*inout_paths == NULL) {
	    *inout_paths = Lst_Init();
	}
	Lst_Append(*inout_paths, dirSearchPath);
	break;
    case Main:
	if (!Lst_IsEmpty(create)) {
	    *inout_specType = Not;
	}
	break;
    case Begin:
    case End:
    case Stale:
    case dotError:
    case Interrupt: {
	GNode *gn = Targ_GetNode(line);
	if (doing_depend)
	    ParseMark(gn);
	gn->type |= OP_NOTMAIN|OP_SPECIAL;
	Lst_Append(targets, gn);
	break;
    }
    case Default: {
	GNode *gn = Targ_NewGN(".DEFAULT");
	gn->type |= OP_NOTMAIN|OP_TRANSFORM;
	Lst_Append(targets, gn);
	DEFAULT = gn;
	break;
    }
    case DeleteOnError:
	deleteOnError = TRUE;
	break;
    case NotParallel:
	maxJobs = 1;
	break;
    case SingleShell:
	compatMake = TRUE;
	break;
    case Order:
	predecessor = NULL;
	break;
    default:
	break;
    }
}

/*
 * .PATH<suffix> has to be handled specially.
 * Call on the suffix module to give us a path to modify.
 */
static Boolean
ParseDoDependencyTargetPath(const char *const line,
			    SearchPathList **const inout_paths)
{
    SearchPath *path;

    path = Suff_GetPath(&line[5]);
    if (path == NULL) {
	Parse_Error(PARSE_FATAL,
		    "Suffix '%s' not defined (yet)",
		    &line[5]);
	return FALSE;
    } else {
	if (*inout_paths == NULL) {
	    *inout_paths = Lst_Init();
	}
	Lst_Append(*inout_paths, path);
    }
    return TRUE;
}

/*
 * See if it's a special target and if so set specType to match it.
 */
static Boolean
ParseDoDependencyTarget(const char *const line,
			ParseSpecial *const inout_specType,
			GNodeType *out_tOp,
			SearchPathList **inout_paths)
{
    int keywd;

    if (!(*line == '.' && ch_isupper(line[1])))
	return TRUE;

    /*
     * See if the target is a special target that must have it
     * or its sources handled specially.
     */
    keywd = ParseFindKeyword(line);
    if (keywd != -1) {
	if (*inout_specType == ExPath && parseKeywords[keywd].spec != ExPath) {
	    Parse_Error(PARSE_FATAL, "Mismatched special targets");
	    return FALSE;
	}

	*inout_specType = parseKeywords[keywd].spec;
	*out_tOp = parseKeywords[keywd].op;

	ParseDoDependencyTargetSpecial(inout_specType, line, inout_paths);

    } else if (strncmp(line, ".PATH", 5) == 0) {
	*inout_specType = ExPath;
	if (!ParseDoDependencyTargetPath(line, inout_paths))
	    return FALSE;
    }
    return TRUE;
}

static void
ParseDoDependencyTargetMundane(char *const line,
			       StringList *const curTargs)
{
    if (Dir_HasWildcards(line)) {
	/*
	 * Targets are to be sought only in the current directory,
	 * so create an empty path for the thing. Note we need to
	 * use Dir_Destroy in the destruction of the path as the
	 * Dir module could have added a directory to the path...
	 */
	SearchPath *emptyPath = Lst_Init();

	Dir_Expand(line, emptyPath, curTargs);

	Lst_Destroy(emptyPath, Dir_Destroy);
    } else {
	/*
	 * No wildcards, but we want to avoid code duplication,
	 * so create a list with the word on it.
	 */
	Lst_Append(curTargs, line);
    }

    /* Apply the targets. */

    while(!Lst_IsEmpty(curTargs)) {
	char *targName = Lst_Dequeue(curTargs);
	GNode *gn = Suff_IsTransform(targName)
		    ? Suff_AddTransform(targName)
		    : Targ_GetNode(targName);
	if (doing_depend)
	    ParseMark(gn);

	Lst_Append(targets, gn);
    }
}

static void
ParseDoDependencyTargetExtraWarn(char **pp, const char *lstart)
{
    Boolean warning = FALSE;
    char *cp = *pp;

    while (*cp && (ParseIsEscaped(lstart, cp) ||
		   (*cp != '!' && *cp != ':'))) {
	if (ParseIsEscaped(lstart, cp) ||
	    (*cp != ' ' && *cp != '\t')) {
	    warning = TRUE;
	}
	cp++;
    }
    if (warning) {
	Parse_Error(PARSE_WARNING, "Extra target ignored");
    }
    *pp = cp;
}

static void
ParseDoDependencyCheckSpec(ParseSpecial const specType)
{
    switch(specType) {
    default:
	Parse_Error(PARSE_WARNING,
		    "Special and mundane targets don't mix. Mundane ones ignored");
	break;
    case Default:
    case Stale:
    case Begin:
    case End:
    case dotError:
    case Interrupt:
	/*
	 * These four create nodes on which to hang commands, so
	 * targets shouldn't be empty...
	 */
    case Not:
	/*
	 * Nothing special here -- targets can be empty if it wants.
	 */
	break;
    }
}

static Boolean
ParseDoDependencyParseOp(char **const pp, const char *const lstart,
			 GNodeType *const out_op)
{
    const char *cp = *pp;

    if (*cp == '!') {
	*out_op = OP_FORCE;
	(*pp)++;
	return TRUE;
    }

    if (*cp == ':') {
	if (cp[1] == ':') {
	    *out_op = OP_DOUBLEDEP;
	    (*pp) += 2;
	} else {
	    *out_op = OP_DEPENDS;
	    (*pp)++;
	}
	return TRUE;
    }

    {
	const char *msg = lstart[0] == '.' ? "Unknown directive"
					   : "Missing dependency operator";
	Parse_Error(PARSE_FATAL, "%s", msg);
	return FALSE;
    }
}

static void
ParseDoDependencySourcesEmpty(ParseSpecial const specType,
			      SearchPathList *const paths)
{
    switch (specType) {
    case Suffixes:
	Suff_ClearSuffixes();
	break;
    case Precious:
	allPrecious = TRUE;
	break;
    case Ignore:
	ignoreErrors = TRUE;
	break;
    case Silent:
	beSilent = TRUE;
	break;
    case ExPath:
	if (paths != NULL)
	    Lst_ForEach(paths, ParseClearPath, NULL);
	Dir_SetPATH();
	break;
#ifdef POSIX
    case Posix:
	Var_Set("%POSIX", "1003.2", VAR_GLOBAL);
	break;
#endif
    default:
	break;
    }
}

/*
 * If the target was one that doesn't take files as its sources
 * but takes something like suffixes, we take each
 * space-separated word on the line as a something and deal
 * with it accordingly.
 *
 * If the target was .SUFFIXES, we take each source as a
 * suffix and add it to the list of suffixes maintained by the
 * Suff module.
 *
 * If the target was a .PATH, we add the source as a directory
 * to search on the search path.
 *
 * If it was .INCLUDES, the source is taken to be the suffix of
 * files which will be #included and whose search path should
 * be present in the .INCLUDES variable.
 *
 * If it was .LIBS, the source is taken to be the suffix of
 * files which are considered libraries and whose search path
 * should be present in the .LIBS variable.
 *
 * If it was .NULL, the source is the suffix to use when a file
 * has no valid suffix.
 *
 * If it was .OBJDIR, the source is a new definition for .OBJDIR,
 * and will cause make to do a new chdir to that path.
 */
static void
ParseDoDependencySourceSpecial(ParseSpecial const specType, char *const line,
			       SearchPathList *const paths)
{
    switch (specType) {
    case Suffixes:
	Suff_AddSuffix(line, &mainNode);
	break;
    case ExPath:
	if (paths != NULL)
	    Lst_ForEach(paths, ParseAddDir, line);
	break;
    case Includes:
	Suff_AddInclude(line);
	break;
    case Libs:
	Suff_AddLib(line);
	break;
    case Null:
	Suff_SetNull(line);
	break;
    case ExObjdir:
	Main_SetObjdir("%s", line);
	break;
    default:
	break;
    }
}

static Boolean
ParseDoDependencyTargets(char **const inout_cp,
			 char **const inout_line,
			 const char *const lstart,
			 ParseSpecial *const inout_specType,
			 GNodeType *const inout_tOp,
			 SearchPathList **const inout_paths,
			 StringList *const curTargs)
{
    char *cp = *inout_cp;
    char *line = *inout_line;
    char savec;

    for (;;) {
	/*
	 * Here LINE points to the beginning of the next word, and
	 * LSTART points to the actual beginning of the line.
	 */

	/* Find the end of the next word. */
	cp = line;
	ParseDependencyTargetWord(&cp, lstart);

	/*
	 * If the word is followed by a left parenthesis, it's the
	 * name of an object file inside an archive (ar file).
	 */
	if (!ParseIsEscaped(lstart, cp) && *cp == '(') {
	    /*
	     * Archives must be handled specially to make sure the OP_ARCHV
	     * flag is set in their 'type' field, for one thing, and because
	     * things like "archive(file1.o file2.o file3.o)" are permissible.
	     * Arch_ParseArchive will set 'line' to be the first non-blank
	     * after the archive-spec. It creates/finds nodes for the members
	     * and places them on the given list, returning TRUE if all
	     * went well and FALSE if there was an error in the
	     * specification. On error, line should remain untouched.
	     */
	    if (!Arch_ParseArchive(&line, targets, VAR_CMD)) {
		Parse_Error(PARSE_FATAL,
			    "Error in archive specification: \"%s\"", line);
		return FALSE;
	    } else {
		/* Done with this word; on to the next. */
		cp = line;
		continue;
	    }
	}

	if (!*cp) {
	    ParseErrorNoDependency(lstart, line);
	    return FALSE;
	}

	/* Insert a null terminator. */
	savec = *cp;
	*cp = '\0';

	if (!ParseDoDependencyTarget(line, inout_specType, inout_tOp,
				     inout_paths))
	    return FALSE;

	/*
	 * Have word in line. Get or create its node and stick it at
	 * the end of the targets list
	 */
	if (*inout_specType == Not && *line != '\0') {
	    ParseDoDependencyTargetMundane(line, curTargs);
	} else if (*inout_specType == ExPath && *line != '.' && *line != '\0') {
	    Parse_Error(PARSE_WARNING, "Extra target (%s) ignored", line);
	}

	/* Don't need the inserted null terminator any more. */
	*cp = savec;

	/*
	 * If it is a special type and not .PATH, it's the only target we
	 * allow on this line...
	 */
	if (*inout_specType != Not && *inout_specType != ExPath) {
	    ParseDoDependencyTargetExtraWarn(&cp, lstart);
	} else {
	    pp_skip_whitespace(&cp);
	}
	line = cp;
	if (*line == '\0')
	    break;
	if ((*line == '!' || *line == ':') && !ParseIsEscaped(lstart, line))
	    break;
    }

    *inout_cp = cp;
    *inout_line = line;
    return TRUE;
}

/* Parse a dependency line consisting of targets, followed by a dependency
 * operator, optionally followed by sources.
 *
 * The nodes of the sources are linked as children to the nodes of the
 * targets. Nodes are created as necessary.
 *
 * The operator is applied to each node in the global 'targets' list,
 * which is where the nodes found for the targets are kept, by means of
 * the ParseDoOp function.
 *
 * The sources are parsed in much the same way as the targets, except
 * that they are expanded using the wildcarding scheme of the C-Shell,
 * and all instances of the resulting words in the list of all targets
 * are found. Each of the resulting nodes is then linked to each of the
 * targets as one of its children.
 *
 * Certain targets and sources such as .PHONY or .PRECIOUS are handled
 * specially. These are the ones detailed by the specType variable.
 *
 * The storing of transformation rules such as '.c.o' is also taken care of
 * here. A target is recognized as a transformation rule by calling
 * Suff_IsTransform. If it is a transformation rule, its node is gotten
 * from the suffix module via Suff_AddTransform rather than the standard
 * Targ_FindNode in the target module.
 */
static void
ParseDoDependency(char *line)
{
    char *cp;			/* our current position */
    GNodeType op;		/* the operator on the line */
    char            savec;	/* a place to save a character */
    SearchPathList *paths;	/* search paths to alter when parsing
				 * a list of .PATH targets */
    int tOp;			/* operator from special target */
    GNodeList *sources;		/* archive sources after expansion */
    StringList *curTargs;	/* target names to be found and added
				 * to the targets list */
    char	   *lstart = line;

    /*
     * specType contains the SPECial TYPE of the current target. It is Not
     * if the target is unspecial. If it *is* special, however, the children
     * are linked as children of the parent but not vice versa.
     */
    ParseSpecial specType = Not;

    DEBUG1(PARSE, "ParseDoDependency(%s)\n", line);
    tOp = 0;

    paths = NULL;

    curTargs = Lst_Init();

    /*
     * First, grind through the targets.
     */
    if (!ParseDoDependencyTargets(&cp, &line, lstart, &specType, &tOp, &paths,
				  curTargs))
	goto out;

    /*
     * Don't need the list of target names anymore...
     */
    Lst_Free(curTargs);
    curTargs = NULL;

    if (!Lst_IsEmpty(targets))
        ParseDoDependencyCheckSpec(specType);

    /*
     * Have now parsed all the target names. Must parse the operator next.
     */
    if (!ParseDoDependencyParseOp(&cp, lstart, &op))
        goto out;

    /*
     * Apply the operator to the target. This is how we remember which
     * operator a target was defined with. It fails if the operator
     * used isn't consistent across all references.
     */
    ApplyDependencyOperator(op);

    /*
     * Onward to the sources.
     *
     * LINE will now point to the first source word, if any, or the
     * end of the string if not.
     */
    pp_skip_whitespace(&cp);
    line = cp;

    /*
     * Several special targets take different actions if present with no
     * sources:
     *	a .SUFFIXES line with no sources clears out all old suffixes
     *	a .PRECIOUS line makes all targets precious
     *	a .IGNORE line ignores errors for all targets
     *	a .SILENT line creates silence when making all targets
     *	a .PATH removes all directories from the search path(s).
     */
    if (!*line) {
        ParseDoDependencySourcesEmpty(specType, paths);
    } else if (specType == MFlags) {
	/*
	 * Call on functions in main.c to deal with these arguments and
	 * set the initial character to a null-character so the loop to
	 * get sources won't get anything
	 */
	Main_ParseArgLine(line);
	*line = '\0';
    } else if (specType == ExShell) {
	if (!Job_ParseShell(line)) {
	    Parse_Error(PARSE_FATAL, "improper shell specification");
	    goto out;
	}
	*line = '\0';
    } else if (specType == NotParallel || specType == SingleShell ||
	    specType == DeleteOnError) {
	*line = '\0';
    }

    /*
     * NOW GO FOR THE SOURCES
     */
    if (specType == Suffixes || specType == ExPath ||
	specType == Includes || specType == Libs ||
	specType == Null || specType == ExObjdir)
    {
	while (*line) {
	    while (*cp && !ch_isspace(*cp)) {
		cp++;
	    }
	    savec = *cp;
	    *cp = '\0';
	    ParseDoDependencySourceSpecial(specType, line, paths);
	    *cp = savec;
	    if (savec != '\0') {
		cp++;
	    }
	    pp_skip_whitespace(&cp);
	    line = cp;
	}
	if (paths) {
	    Lst_Free(paths);
	    paths = NULL;
	}
	if (specType == ExPath)
	    Dir_SetPATH();
    } else {
	assert(paths == NULL);
	while (*line) {
	    /*
	     * The targets take real sources, so we must beware of archive
	     * specifications (i.e. things with left parentheses in them)
	     * and handle them accordingly.
	     */
	    for (; *cp && !ch_isspace(*cp); cp++) {
		if (*cp == '(' && cp > line && cp[-1] != '$') {
		    /*
		     * Only stop for a left parenthesis if it isn't at the
		     * start of a word (that'll be for variable changes
		     * later) and isn't preceded by a dollar sign (a dynamic
		     * source).
		     */
		    break;
		}
	    }

	    if (*cp == '(') {
		sources = Lst_Init();
		if (!Arch_ParseArchive(&line, sources, VAR_CMD)) {
		    Parse_Error(PARSE_FATAL,
				 "Error in source archive spec \"%s\"", line);
		    goto out;
		}

		while (!Lst_IsEmpty(sources)) {
		    GNode *gn = Lst_Dequeue(sources);
		    ParseDoSrc(tOp, gn->name, specType);
		}
		Lst_Free(sources);
		cp = line;
	    } else {
		if (*cp) {
		    *cp = '\0';
		    cp++;
		}

		ParseDoSrc(tOp, line, specType);
	    }
	    pp_skip_whitespace(&cp);
	    line = cp;
	}
    }

    FindMainTarget();

out:
    if (paths != NULL)
	Lst_Free(paths);
    if (curTargs != NULL)
	Lst_Free(curTargs);
}

/* Parse a variable assignment, consisting of a single-word variable name,
 * optional whitespace, an assignment operator, optional whitespace and the
 * variable value.
 *
 * Used for both lines in a file and command line arguments. */
Boolean
Parse_IsVar(const char *p, VarAssign *out_var)
{
    const char *firstSpace = NULL;
    char ch;
    int level = 0;

    /* Skip to variable name */
    while (*p == ' ' || *p == '\t')
	p++;

    /* During parsing, the '+' of the '+=' operator is initially parsed
     * as part of the variable name.  It is later corrected, as is the ':sh'
     * modifier. Of these two (nameEnd and op), the earlier one determines the
     * actual end of the variable name. */
    out_var->nameStart = p;
#ifdef CLEANUP
    out_var->nameEndDraft = NULL;
    out_var->varname = NULL;
    out_var->eq = NULL;
    out_var->op = VAR_NORMAL;
    out_var->value = NULL;
#endif

    /* Scan for one of the assignment operators outside a variable expansion */
    while ((ch = *p++) != 0) {
	if (ch == '(' || ch == '{') {
	    level++;
	    continue;
	}
	if (ch == ')' || ch == '}') {
	    level--;
	    continue;
	}

	if (level != 0)
	    continue;

	if (ch == ' ' || ch == '\t')
	    if (firstSpace == NULL)
	        firstSpace = p - 1;
	while (ch == ' ' || ch == '\t')
	    ch = *p++;

#ifdef SUNSHCMD
	if (ch == ':' && strncmp(p, "sh", 2) == 0) {
	    p += 2;
	    continue;
	}
#endif
	if (ch == '=') {
	    out_var->eq = p - 1;
	    out_var->nameEndDraft = firstSpace != NULL ? firstSpace : p - 1;
	    out_var->op = VAR_NORMAL;
	    cpp_skip_whitespace(&p);
	    out_var->value = p;
	    return TRUE;
	}
	if (*p == '=' && (ch == '+' || ch == ':' || ch == '?' || ch == '!')) {
	    out_var->eq = p;
	    out_var->nameEndDraft = firstSpace != NULL ? firstSpace : p;
	    out_var->op = ch == '+' ? VAR_APPEND :
			  ch == ':' ? VAR_SUBST :
			  ch == '?' ? VAR_DEFAULT : VAR_SHELL;
	    p++;
	    cpp_skip_whitespace(&p);
	    out_var->value = p;
	    return TRUE;
	}
	if (firstSpace != NULL)
	    return FALSE;
    }

    return FALSE;
}

/* Determine the assignment operator and adjust the end of the variable
 * name accordingly. */
static void
ParseVarassignOp(VarAssign *var)
{
    const char *op = var->eq;
    const char * const name = var->nameStart;
    VarAssignOp type;

    if (op > name && op[-1] == '+') {
	type = VAR_APPEND;
	op--;

    } else if (op > name && op[-1] == '?') {
        op--;
        type = VAR_DEFAULT;

    } else if (op > name && op[-1] == ':') {
	op--;
	type = VAR_SUBST;

    } else if (op > name && op[-1] == '!') {
	op--;
	type = VAR_SHELL;

    } else {
	type = VAR_NORMAL;
#ifdef SUNSHCMD
	while (op > name && ch_isspace(op[-1]))
	    op--;

	if (op >= name + 3 && op[-3] == ':' && op[-2] == 's' && op[-1] == 'h') {
	    type = VAR_SHELL;
	    op -= 3;
	}
#endif
    }

    {
	const char *nameEnd = var->nameEndDraft < op ? var->nameEndDraft : op;
	var->varname = bmake_strsedup(var->nameStart, nameEnd);
	var->op = type;
    }
}

static void
VarCheckSyntax(VarAssignOp type, const char *uvalue, GNode *ctxt)
{
    if (DEBUG(LINT)) {
	if (type != VAR_SUBST && strchr(uvalue, '$') != NULL) {
	    /* Check for syntax errors such as unclosed expressions or
	     * unknown modifiers. */
	    char *expandedValue;

	    (void)Var_Subst(uvalue, ctxt, VARE_NONE, &expandedValue);
	    /* TODO: handle errors */
	    free(expandedValue);
	}
    }
}

static Boolean
VarAssign_Eval(VarAssign *var, GNode *ctxt,
	       const char **out_avalue, void **out_avalue_freeIt)
{
    const char *uvalue = var->value;
    const char *name = var->varname;
    const VarAssignOp type = var->op;
    const char *avalue = uvalue;
    void *avalue_freeIt = NULL;

    if (type == VAR_APPEND) {
	Var_Append(name, uvalue, ctxt);
    } else if (type == VAR_SUBST) {
        char *evalue;
	/*
	 * Allow variables in the old value to be undefined, but leave their
	 * expressions alone -- this is done by forcing oldVars to be false.
	 * XXX: This can cause recursive variables, but that's not hard to do,
	 * and this allows someone to do something like
	 *
	 *  CFLAGS = $(.INCLUDES)
	 *  CFLAGS := -I.. $(CFLAGS)
	 *
	 * And not get an error.
	 */
	Boolean	  oldOldVars = oldVars;

	oldVars = FALSE;

	/*
	 * make sure that we set the variable the first time to nothing
	 * so that it gets substituted!
	 */
	if (!Var_Exists(name, ctxt))
	    Var_Set(name, "", ctxt);

	(void)Var_Subst(uvalue, ctxt, VARE_WANTRES|VARE_ASSIGN, &evalue);
	/* TODO: handle errors */
	oldVars = oldOldVars;
	avalue = evalue;
	avalue_freeIt = evalue;

	Var_Set(name, avalue, ctxt);
    } else if (type == VAR_SHELL) {
        const char *cmd, *errfmt;
        char *cmdOut;
        void *cmd_freeIt = NULL;

	cmd = uvalue;
	if (strchr(cmd, '$') != NULL) {
	    char *ecmd;
	    (void)Var_Subst(cmd, VAR_CMD, VARE_UNDEFERR|VARE_WANTRES, &ecmd);
	    /* TODO: handle errors */
	    cmd = cmd_freeIt = ecmd;
	}

	cmdOut = Cmd_Exec(cmd, &errfmt);
	Var_Set(name, cmdOut, ctxt);
	avalue = avalue_freeIt = cmdOut;

	if (errfmt)
	    Parse_Error(PARSE_WARNING, errfmt, cmd);

	free(cmd_freeIt);
    } else {
	if (type == VAR_DEFAULT && Var_Exists(var->varname, ctxt)) {
	    *out_avalue_freeIt = NULL;
	    return FALSE;
	}

	/* Normal assignment -- just do it. */
	Var_Set(name, uvalue, ctxt);
    }

    *out_avalue = avalue;
    *out_avalue_freeIt = avalue_freeIt;
    return TRUE;
}

static void
VarAssignSpecial(const char *name, const char *avalue)
{
    if (strcmp(name, MAKEOVERRIDES) == 0)
	Main_ExportMAKEFLAGS(FALSE);	/* re-export MAKEFLAGS */
    else if (strcmp(name, ".CURDIR") == 0) {
	/*
	 * Someone is being (too?) clever...
	 * Let's pretend they know what they are doing and
	 * re-initialize the 'cur' CachedDir.
	 */
	Dir_InitCur(avalue);
	Dir_SetPATH();
    } else if (strcmp(name, MAKE_JOB_PREFIX) == 0) {
	Job_SetPrefix();
    } else if (strcmp(name, MAKE_EXPORTED) == 0) {
	Var_Export(avalue, FALSE);
    }
}

/* Take the variable assignment in the passed line and execute it.
 *
 * Note: There is a lexical ambiguity with assignment modifier characters
 * in variable names. This routine interprets the character before the =
 * as a modifier. Therefore, an assignment like
 *	C++=/usr/bin/CC
 * is interpreted as "C+ +=" instead of "C++ =".
 *
 * Input:
 *	p		A line guaranteed to be a variable assignment
 *			(see Parse_IsVar).
 *	ctxt		Context in which to do the assignment
 */
void
Parse_DoVar(VarAssign *var, GNode *ctxt)
{
    const char *avalue;		/* actual value (maybe expanded) */
    void *avalue_freeIt;

    ParseVarassignOp(var);

    VarCheckSyntax(var->op, var->value, ctxt);
    if (VarAssign_Eval(var, ctxt, &avalue, &avalue_freeIt))
	VarAssignSpecial(var->varname, avalue);

    free(avalue_freeIt);
    free(var->varname);
}


/*
 * ParseMaybeSubMake --
 *	Scan the command string to see if it a possible submake node
 * Input:
 *	cmd		the command to scan
 * Results:
 *	TRUE if the command is possibly a submake, FALSE if not.
 */
static Boolean
ParseMaybeSubMake(const char *cmd)
{
    size_t i;
    static struct {
	const char *name;
	size_t len;
    } vals[] = {
#define MKV(A)	{	A, sizeof(A) - 1	}
	MKV("${MAKE}"),
	MKV("${.MAKE}"),
	MKV("$(MAKE)"),
	MKV("$(.MAKE)"),
	MKV("make"),
    };
    for (i = 0; i < sizeof(vals)/sizeof(vals[0]); i++) {
	char *ptr;
	if ((ptr = strstr(cmd, vals[i].name)) == NULL)
	    continue;
	if ((ptr == cmd || !ch_isalnum(ptr[-1]))
	    && !ch_isalnum(ptr[vals[i].len]))
	    return TRUE;
    }
    return FALSE;
}

/* Append the command to the target node.
 *
 * The node may be marked as a submake node if the command is determined to
 * be that. */
static void
ParseAddCmd(GNode *gn, char *cmd)
{
    /* Add to last (ie current) cohort for :: targets */
    if ((gn->type & OP_DOUBLEDEP) && gn->cohorts->last != NULL)
	gn = gn->cohorts->last->datum;

    /* if target already supplied, ignore commands */
    if (!(gn->type & OP_HAS_COMMANDS)) {
	Lst_Append(gn->commands, cmd);
	if (ParseMaybeSubMake(cmd))
	    gn->type |= OP_SUBMAKE;
	ParseMark(gn);
    } else {
#if 0
	/* XXX: We cannot do this until we fix the tree */
	Lst_Append(gn->commands, cmd);
	Parse_Error(PARSE_WARNING,
		     "overriding commands for target \"%s\"; "
		     "previous commands defined at %s: %d ignored",
		     gn->name, gn->fname, gn->lineno);
#else
	Parse_Error(PARSE_WARNING,
		     "duplicate script for target \"%s\" ignored",
		     gn->name);
	ParseErrorInternal(gn->fname, gn->lineno, PARSE_WARNING,
			    "using previous script for \"%s\" defined here",
			    gn->name);
#endif
    }
}

/* Callback procedure for Parse_File when destroying the list of targets on
 * the last dependency line. Marks a target as already having commands if it
 * does, to keep from having shell commands on multiple dependency lines. */
static void
ParseHasCommands(void *gnp)
{
    GNode *gn = (GNode *)gnp;
    if (!Lst_IsEmpty(gn->commands)) {
	gn->type |= OP_HAS_COMMANDS;
    }
}

/* Add a directory to the path searched for included makefiles bracketed
 * by double-quotes. */
void
Parse_AddIncludeDir(const char *dir)
{
    (void)Dir_AddDir(parseIncPath, dir);
}

/* Push to another file.
 *
 * The input is the line minus the '.'. A file spec is a string enclosed in
 * <> or "". The <> file is looked for only in sysIncPath. The "" file is
 * first searched in the parsedir and then in the directories specified by
 * the -I command line options.
 */
static void
Parse_include_file(char *file, Boolean isSystem, Boolean depinc, int silent)
{
    struct loadedfile *lf;
    char          *fullname;	/* full pathname of file */
    char          *newName;
    char          *prefEnd, *incdir;
    int           fd;
    int           i;

    /*
     * Now we know the file's name and its search path, we attempt to
     * find the durn thing. A return of NULL indicates the file don't
     * exist.
     */
    fullname = file[0] == '/' ? bmake_strdup(file) : NULL;

    if (fullname == NULL && !isSystem) {
	/*
	 * Include files contained in double-quotes are first searched for
	 * relative to the including file's location. We don't want to
	 * cd there, of course, so we just tack on the old file's
	 * leading path components and call Dir_FindFile to see if
	 * we can locate the beast.
	 */

	incdir = bmake_strdup(curFile->fname);
	prefEnd = strrchr(incdir, '/');
	if (prefEnd != NULL) {
	    *prefEnd = '\0';
	    /* Now do lexical processing of leading "../" on the filename */
	    for (i = 0; strncmp(file + i, "../", 3) == 0; i += 3) {
		prefEnd = strrchr(incdir + 1, '/');
		if (prefEnd == NULL || strcmp(prefEnd, "/..") == 0)
		    break;
		*prefEnd = '\0';
	    }
	    newName = str_concat3(incdir, "/", file + i);
	    fullname = Dir_FindFile(newName, parseIncPath);
	    if (fullname == NULL)
		fullname = Dir_FindFile(newName, dirSearchPath);
	    free(newName);
	}
	free(incdir);

	if (fullname == NULL) {
	    /*
	     * Makefile wasn't found in same directory as included makefile.
	     * Search for it first on the -I search path,
	     * then on the .PATH search path, if not found in a -I directory.
	     * If we have a suffix specific path we should use that.
	     */
	    char *suff;
	    SearchPath *suffPath = NULL;

	    if ((suff = strrchr(file, '.'))) {
		suffPath = Suff_GetPath(suff);
		if (suffPath != NULL) {
		    fullname = Dir_FindFile(file, suffPath);
		}
	    }
	    if (fullname == NULL) {
		fullname = Dir_FindFile(file, parseIncPath);
		if (fullname == NULL) {
		    fullname = Dir_FindFile(file, dirSearchPath);
		}
	    }
	}
    }

    /* Looking for a system file or file still not found */
    if (fullname == NULL) {
	/*
	 * Look for it on the system path
	 */
	fullname = Dir_FindFile(file,
		    Lst_IsEmpty(sysIncPath) ? defIncPath : sysIncPath);
    }

    if (fullname == NULL) {
	if (!silent)
	    Parse_Error(PARSE_FATAL, "Could not find %s", file);
	return;
    }

    /* Actually open the file... */
    fd = open(fullname, O_RDONLY);
    if (fd == -1) {
	if (!silent)
	    Parse_Error(PARSE_FATAL, "Cannot open %s", fullname);
	free(fullname);
	return;
    }

    /* load it */
    lf = loadfile(fullname, fd);

    /* Start reading from this file next */
    Parse_SetInput(fullname, 0, -1, loadedfile_nextbuf, lf);
    curFile->lf = lf;
    if (depinc)
	doing_depend = depinc;		/* only turn it on */
}

static void
ParseDoInclude(char *line)
{
    char          endc;		/* the character which ends the file spec */
    char          *cp;		/* current position in file spec */
    int		  silent = *line != 'i';
    char	  *file = &line[7 + silent];

    /* Skip to delimiter character so we know where to look */
    while (*file == ' ' || *file == '\t')
	file++;

    if (*file != '"' && *file != '<') {
	Parse_Error(PARSE_FATAL,
	    ".include filename must be delimited by '\"' or '<'");
	return;
    }

    /*
     * Set the search path on which to find the include file based on the
     * characters which bracket its name. Angle-brackets imply it's
     * a system Makefile while double-quotes imply it's a user makefile
     */
    if (*file == '<') {
	endc = '>';
    } else {
	endc = '"';
    }

    /* Skip to matching delimiter */
    for (cp = ++file; *cp && *cp != endc; cp++)
	continue;

    if (*cp != endc) {
	Parse_Error(PARSE_FATAL,
		     "Unclosed %cinclude filename. '%c' expected",
		     '.', endc);
	return;
    }
    *cp = '\0';

    /*
     * Substitute for any variables in the file name before trying to
     * find the thing.
     */
    (void)Var_Subst(file, VAR_CMD, VARE_WANTRES, &file);
    /* TODO: handle errors */

    Parse_include_file(file, endc == '>', *line == 'd', silent);
    free(file);
}

/* Split filename into dirname + basename, then assign these to the
 * given variables. */
static void
SetFilenameVars(const char *filename, const char *dirvar, const char *filevar)
{
    const char *slash, *dirname, *basename;
    void *freeIt;

    slash = strrchr(filename, '/');
    if (slash == NULL) {
	dirname = curdir;
	basename = filename;
	freeIt = NULL;
    } else {
	dirname = freeIt = bmake_strsedup(filename, slash);
	basename = slash + 1;
    }

    Var_Set(dirvar, dirname, VAR_GLOBAL);
    Var_Set(filevar, basename, VAR_GLOBAL);

    DEBUG5(PARSE, "%s: ${%s} = `%s' ${%s} = `%s'\n",
	   __func__, dirvar, dirname, filevar, basename);
    free(freeIt);
}

/* Return the immediately including file.
 *
 * This is made complicated since the .for loop is implemented as a special
 * kind of .include; see For_Run. */
static const char *
GetActuallyIncludingFile(void)
{
    size_t i;

    /* XXX: Stack was supposed to be an opaque data structure. */
    for (i = includes.len; i > 0; i--) {
	IFile *parent = includes.items[i - 1];
	IFile *child = i < includes.len ? includes.items[i] : curFile;
	if (!child->fromForLoop)
	    return parent->fname;
    }
    return NULL;
}

/* Set .PARSEDIR, .PARSEFILE, .INCLUDEDFROMDIR and .INCLUDEDFROMFILE. */
static void
ParseSetParseFile(const char *filename)
{
    const char *including;

    SetFilenameVars(filename, ".PARSEDIR", ".PARSEFILE");

    including = GetActuallyIncludingFile();
    if (including != NULL) {
	SetFilenameVars(including,
			".INCLUDEDFROMDIR", ".INCLUDEDFROMFILE");
    } else {
	Var_Delete(".INCLUDEDFROMDIR", VAR_GLOBAL);
	Var_Delete(".INCLUDEDFROMFILE", VAR_GLOBAL);
    }
}

/* Track the makefiles we read - so makefiles can set dependencies on them.
 * Avoid adding anything more than once. */
static void
ParseTrackInput(const char *name)
{
    char *fp = NULL;

    const char *old = Var_Value(MAKE_MAKEFILES, VAR_GLOBAL, &fp);
    if (old) {
	size_t name_len = strlen(name);
	const char *ep = old + strlen(old) - name_len;
	/* does it contain name? */
	for (; old != NULL; old = strchr(old, ' ')) {
	    if (*old == ' ')
		old++;
	    if (old >= ep)
		break;			/* cannot contain name */
	    if (memcmp(old, name, name_len) == 0
		    && (old[name_len] == 0 || old[name_len] == ' '))
		goto cleanup;
	}
    }
    Var_Append (MAKE_MAKEFILES, name, VAR_GLOBAL);
 cleanup:
    bmake_free(fp);
}


/* Start Parsing from the given source.
 *
 * The given file is added to the includes stack. */
void
Parse_SetInput(const char *name, int line, int fd,
	char *(*nextbuf)(void *, size_t *), void *arg)
{
    char *buf;
    size_t len;
    Boolean fromForLoop = name == NULL;

    if (fromForLoop)
	name = curFile->fname;
    else
	ParseTrackInput(name);

    if (DEBUG(PARSE))
	debug_printf("%s: file %s, line %d, fd %d, nextbuf %s, arg %p\n",
		     __func__, name, line, fd,
		     nextbuf == loadedfile_nextbuf ? "loadedfile" : "other",
		     arg);

    if (fd == -1 && nextbuf == NULL)
	/* sanity */
	return;

    if (curFile != NULL)
	/* Save existing file info */
	Stack_Push(&includes, curFile);

    /* Allocate and fill in new structure */
    curFile = bmake_malloc(sizeof *curFile);

    /*
     * Once the previous state has been saved, we can get down to reading
     * the new file. We set up the name of the file to be the absolute
     * name of the include file so error messages refer to the right
     * place.
     */
    curFile->fname = bmake_strdup(name);
    curFile->fromForLoop = fromForLoop;
    curFile->lineno = line;
    curFile->first_lineno = line;
    curFile->nextbuf = nextbuf;
    curFile->nextbuf_arg = arg;
    curFile->lf = NULL;
    curFile->depending = doing_depend;	/* restore this on EOF */

    assert(nextbuf != NULL);

    /* Get first block of input data */
    buf = curFile->nextbuf(curFile->nextbuf_arg, &len);
    if (buf == NULL) {
	/* Was all a waste of time ... */
	if (curFile->fname)
	    free(curFile->fname);
	free(curFile);
	return;
    }
    curFile->P_str = buf;
    curFile->P_ptr = buf;
    curFile->P_end = buf+len;

    curFile->cond_depth = Cond_save_depth();
    ParseSetParseFile(name);
}

/* Check if the line is an include directive. */
static Boolean
IsInclude(const char *dir, Boolean sysv)
{
	if (dir[0] == 's' || dir[0] == '-' || (dir[0] == 'd' && !sysv))
		dir++;

	if (strncmp(dir, "include", 7) != 0)
		return FALSE;

	/* Space is not mandatory for BSD .include */
	return !sysv || ch_isspace(dir[7]);
}


#ifdef SYSVINCLUDE
/* Check if the line is a SYSV include directive. */
static Boolean
IsSysVInclude(const char *line)
{
	const char *p;

	if (!IsInclude(line, TRUE))
		return FALSE;

	/* Avoid interpeting a dependency line as an include */
	for (p = line; (p = strchr(p, ':')) != NULL;) {
		if (*++p == '\0') {
			/* end of line -> dependency */
			return FALSE;
		}
		if (*p == ':' || ch_isspace(*p)) {
			/* :: operator or ': ' -> dependency */
			return FALSE;
		}
	}
	return TRUE;
}

/* Push to another file.  The line points to the word "include". */
static void
ParseTraditionalInclude(char *line)
{
    char          *cp;		/* current position in file spec */
    int		   done = 0;
    int		   silent = line[0] != 'i';
    char	  *file = &line[silent + 7];
    char	  *all_files;

    DEBUG2(PARSE, "%s: %s\n", __func__, file);

    pp_skip_whitespace(&file);

    /*
     * Substitute for any variables in the file name before trying to
     * find the thing.
     */
    (void)Var_Subst(file, VAR_CMD, VARE_WANTRES, &all_files);
    /* TODO: handle errors */

    if (*file == '\0') {
	Parse_Error(PARSE_FATAL,
		     "Filename missing from \"include\"");
	goto out;
    }

    for (file = all_files; !done; file = cp + 1) {
	/* Skip to end of line or next whitespace */
	for (cp = file; *cp && !ch_isspace(*cp); cp++)
	    continue;

	if (*cp)
	    *cp = '\0';
	else
	    done = 1;

	Parse_include_file(file, FALSE, FALSE, silent);
    }
out:
    free(all_files);
}
#endif

#ifdef GMAKEEXPORT
/* Parse export <variable>=<value>, and actually export it. */
static void
ParseGmakeExport(char *line)
{
    char	  *variable = &line[6];
    char	  *value;

    DEBUG2(PARSE, "%s: %s\n", __func__, variable);

    pp_skip_whitespace(&variable);

    for (value = variable; *value && *value != '='; value++)
	continue;

    if (*value != '=') {
	Parse_Error(PARSE_FATAL,
		    "Variable/Value missing from \"export\"");
	return;
    }
    *value++ = '\0';			/* terminate variable */

    /*
     * Expand the value before putting it in the environment.
     */
    (void)Var_Subst(value, VAR_CMD, VARE_WANTRES, &value);
    /* TODO: handle errors */

    setenv(variable, value, 1);
    free(value);
}
#endif

/* Called when EOF is reached in the current file. If we were reading an
 * include file, the includes stack is popped and things set up to go back
 * to reading the previous file at the previous location.
 *
 * Results:
 *	CONTINUE if there's more to do. DONE if not.
 */
static int
ParseEOF(void)
{
    char *ptr;
    size_t len;

    assert(curFile->nextbuf != NULL);

    doing_depend = curFile->depending;	/* restore this */
    /* get next input buffer, if any */
    ptr = curFile->nextbuf(curFile->nextbuf_arg, &len);
    curFile->P_ptr = ptr;
    curFile->P_str = ptr;
    curFile->P_end = ptr + len;
    curFile->lineno = curFile->first_lineno;
    if (ptr != NULL) {
	/* Iterate again */
	return CONTINUE;
    }

    /* Ensure the makefile (or loop) didn't have mismatched conditionals */
    Cond_restore_depth(curFile->cond_depth);

    if (curFile->lf != NULL) {
	    loadedfile_destroy(curFile->lf);
	    curFile->lf = NULL;
    }

    /* Dispose of curFile info */
    /* Leak curFile->fname because all the gnodes have pointers to it */
    free(curFile->P_str);
    free(curFile);

    if (Stack_IsEmpty(&includes)) {
	curFile = NULL;
	/* We've run out of input */
	Var_Delete(".PARSEDIR", VAR_GLOBAL);
	Var_Delete(".PARSEFILE", VAR_GLOBAL);
	Var_Delete(".INCLUDEDFROMDIR", VAR_GLOBAL);
	Var_Delete(".INCLUDEDFROMFILE", VAR_GLOBAL);
	return DONE;
    }

    curFile = Stack_Pop(&includes);
    DEBUG2(PARSE, "ParseEOF: returning to file %s, line %d\n",
	   curFile->fname, curFile->lineno);

    ParseSetParseFile(curFile->fname);
    return CONTINUE;
}

#define PARSE_RAW 1
#define PARSE_SKIP 2

static char *
ParseGetLine(int flags)
{
    IFile *cf = curFile;
    char *ptr;
    char ch;
    char *line;
    char *line_end;
    char *escaped;
    char *comment;
    char *tp;

    /* Loop through blank lines and comment lines */
    for (;;) {
	cf->lineno++;
	line = cf->P_ptr;
	ptr = line;
	line_end = line;
	escaped = NULL;
	comment = NULL;
	for (;;) {
	    if (cf->P_end != NULL && ptr == cf->P_end) {
		/* end of buffer */
		ch = 0;
		break;
	    }
	    ch = *ptr;
	    if (ch == 0 || (ch == '\\' && ptr[1] == 0)) {
		if (cf->P_end == NULL)
		    /* End of string (aka for loop) data */
		    break;
		/* see if there is more we can parse */
		while (ptr++ < cf->P_end) {
		    if ((ch = *ptr) == '\n') {
			if (ptr > line && ptr[-1] == '\\')
			    continue;
			Parse_Error(PARSE_WARNING,
			    "Zero byte read from file, skipping rest of line.");
			break;
		    }
		}
		if (cf->nextbuf != NULL) {
		    /*
		     * End of this buffer; return EOF and outer logic
		     * will get the next one. (eww)
		     */
		    break;
		}
		Parse_Error(PARSE_FATAL, "Zero byte read from file");
		return NULL;
	    }

	    if (ch == '\\') {
		/* Don't treat next character as special, remember first one */
		if (escaped == NULL)
		    escaped = ptr;
		if (ptr[1] == '\n')
		    cf->lineno++;
		ptr += 2;
		line_end = ptr;
		continue;
	    }
	    if (ch == '#' && comment == NULL) {
		/* Remember first '#' for comment stripping */
		/* Unless previous char was '[', as in modifier :[#] */
		if (!(ptr > line && ptr[-1] == '['))
		    comment = line_end;
	    }
	    ptr++;
	    if (ch == '\n')
		break;
	    if (!ch_isspace(ch))
		/* We are not interested in trailing whitespace */
		line_end = ptr;
	}

	/* Save next 'to be processed' location */
	cf->P_ptr = ptr;

	/* Check we have a non-comment, non-blank line */
	if (line_end == line || comment == line) {
	    if (ch == 0)
		/* At end of file */
		return NULL;
	    /* Parse another line */
	    continue;
	}

	/* We now have a line of data */
	*line_end = 0;

	if (flags & PARSE_RAW) {
	    /* Leave '\' (etc) in line buffer (eg 'for' lines) */
	    return line;
	}

	if (flags & PARSE_SKIP) {
	    /* Completely ignore non-directives */
	    if (line[0] != '.')
		continue;
	    /* We could do more of the .else/.elif/.endif checks here */
	}
	break;
    }

    /* Brutally ignore anything after a non-escaped '#' in non-commands */
    if (comment != NULL && line[0] != '\t') {
	line_end = comment;
	*line_end = 0;
    }

    /* If we didn't see a '\\' then the in-situ data is fine */
    if (escaped == NULL)
	return line;

    /* Remove escapes from '\n' and '#' */
    tp = ptr = escaped;
    escaped = line;
    for (; ; *tp++ = ch) {
	ch = *ptr++;
	if (ch != '\\') {
	    if (ch == 0)
		break;
	    continue;
	}

	ch = *ptr++;
	if (ch == 0) {
	    /* Delete '\\' at end of buffer */
	    tp--;
	    break;
	}

	if (ch == '#' && line[0] != '\t')
	    /* Delete '\\' from before '#' on non-command lines */
	    continue;

	if (ch != '\n') {
	    /* Leave '\\' in buffer for later */
	    *tp++ = '\\';
	    /* Make sure we don't delete an escaped ' ' from the line end */
	    escaped = tp + 1;
	    continue;
	}

	/* Escaped '\n' replace following whitespace with a single ' ' */
	while (ptr[0] == ' ' || ptr[0] == '\t')
	    ptr++;
	ch = ' ';
    }

    /* Delete any trailing spaces - eg from empty continuations */
    while (tp > escaped && ch_isspace(tp[-1]))
	tp--;

    *tp = 0;
    return line;
}

/* Read an entire line from the input file. Called only by Parse_File.
 *
 * Results:
 *	A line without its newline.
 *
 * Side Effects:
 *	Only those associated with reading a character
 */
static char *
ParseReadLine(void)
{
    char *line;			/* Result */
    int lineno;			/* Saved line # */
    int rval;

    for (;;) {
	line = ParseGetLine(0);
	if (line == NULL)
	    return NULL;

	if (line[0] != '.')
	    return line;

	/*
	 * The line might be a conditional. Ask the conditional module
	 * about it and act accordingly
	 */
	switch (Cond_EvalLine(line)) {
	case COND_SKIP:
	    /* Skip to next conditional that evaluates to COND_PARSE.  */
	    do {
		line = ParseGetLine(PARSE_SKIP);
	    } while (line && Cond_EvalLine(line) != COND_PARSE);
	    if (line == NULL)
		break;
	    continue;
	case COND_PARSE:
	    continue;
	case COND_INVALID:    /* Not a conditional line */
	    /* Check for .for loops */
	    rval = For_Eval(line);
	    if (rval == 0)
		/* Not a .for line */
		break;
	    if (rval < 0)
		/* Syntax error - error printed, ignore line */
		continue;
	    /* Start of a .for loop */
	    lineno = curFile->lineno;
	    /* Accumulate loop lines until matching .endfor */
	    do {
		line = ParseGetLine(PARSE_RAW);
		if (line == NULL) {
		    Parse_Error(PARSE_FATAL,
			     "Unexpected end of file in for loop.");
		    break;
		}
	    } while (For_Accum(line));
	    /* Stash each iteration as a new 'input file' */
	    For_Run(lineno);
	    /* Read next line from for-loop buffer */
	    continue;
	}
	return line;
    }
}

static void
SuffEndTransform(void *target, void *unused MAKE_ATTR_UNUSED)
{
    Suff_EndTransform(target);
}

static void
FinishDependencyGroup(void)
{
    if (targets != NULL) {
	Lst_ForEach(targets, SuffEndTransform, NULL);
	Lst_Destroy(targets, ParseHasCommands);
	targets = NULL;
    }
}

/* Add the command to each target from the current dependency spec. */
static void
ParseLine_ShellCommand(char *cp)
{
    pp_skip_whitespace(&cp);
    if (*cp == '\0')
	return;			/* skip empty commands */

    if (targets == NULL) {
	Parse_Error(PARSE_FATAL, "Unassociated shell command \"%s\"", cp);
	return;
    }

    {
	char *cmd = bmake_strdup(cp);
	GNodeListNode *ln;

	for (ln = targets->first; ln != NULL; ln = ln->next) {
	    GNode *gn = ln->datum;
	    ParseAddCmd(gn, cmd);
	}
#ifdef CLEANUP
	Lst_Append(targCmds, cmd);
#endif
    }
}

/* Parse a top-level makefile into its component parts, incorporating them
 * into the global dependency graph.
 *
 * Input:
 *	name		The name of the file being read
 *	fd		The open file to parse; will be closed at the end
 */
void
Parse_File(const char *name, int fd)
{
    char	  *cp;		/* pointer into the line */
    char          *line;	/* the line we're working on */
    struct loadedfile *lf;

    lf = loadfile(name, fd);

    assert(targets == NULL);
    fatals = 0;

    if (name == NULL)
	name = "(stdin)";

    Parse_SetInput(name, 0, -1, loadedfile_nextbuf, lf);
    curFile->lf = lf;

    do {
	for (; (line = ParseReadLine()) != NULL; ) {
	    DEBUG2(PARSE, "ParseReadLine (%d): '%s'\n", curFile->lineno, line);
	    if (*line == '.') {
		/*
		 * Lines that begin with the special character may be
		 * include or undef directives.
		 * On the other hand they can be suffix rules (.c.o: ...)
		 * or just dependencies for filenames that start '.'.
		 */
		cp = line + 1;
		pp_skip_whitespace(&cp);
		if (IsInclude(cp, FALSE)) {
		    ParseDoInclude(cp);
		    continue;
		}
		if (strncmp(cp, "undef", 5) == 0) {
		    const char *varname;
		    cp += 5;
		    pp_skip_whitespace(&cp);
		    varname = cp;
		    for (; !ch_isspace(*cp) && *cp != '\0'; cp++)
			continue;
		    *cp = '\0';
		    Var_Delete(varname, VAR_GLOBAL);
		    /* TODO: undefine all variables, not only the first */
		    /* TODO: use Str_Words, like everywhere else */
		    continue;
		} else if (strncmp(cp, "export", 6) == 0) {
		    cp += 6;
		    pp_skip_whitespace(&cp);
		    Var_Export(cp, TRUE);
		    continue;
		} else if (strncmp(cp, "unexport", 8) == 0) {
		    Var_UnExport(cp);
		    continue;
		} else if (strncmp(cp, "info", 4) == 0 ||
			   strncmp(cp, "error", 5) == 0 ||
			   strncmp(cp, "warning", 7) == 0) {
		    if (ParseMessage(cp))
			continue;
		}
	    }

	    if (*line == '\t') {
		/*
		 * If a line starts with a tab, it can only hope to be
		 * a creation command.
		 */
		cp = line + 1;
	      shellCommand:
	        ParseLine_ShellCommand(cp);
		continue;
	    }

#ifdef SYSVINCLUDE
	    if (IsSysVInclude(line)) {
		/*
		 * It's an S3/S5-style "include".
		 */
		ParseTraditionalInclude(line);
		continue;
	    }
#endif
#ifdef GMAKEEXPORT
	    if (strncmp(line, "export", 6) == 0 && ch_isspace(line[6]) &&
		strchr(line, ':') == NULL) {
		/*
		 * It's a Gmake "export".
		 */
		ParseGmakeExport(line);
		continue;
	    }
#endif
	    {
	        VarAssign var;
		if (Parse_IsVar(line, &var)) {
		    FinishDependencyGroup();
		    Parse_DoVar(&var, VAR_GLOBAL);
		    continue;
		}
	    }

#ifndef POSIX
	    /*
	     * To make life easier on novices, if the line is indented we
	     * first make sure the line has a dependency operator in it.
	     * If it doesn't have an operator and we're in a dependency
	     * line's script, we assume it's actually a shell command
	     * and add it to the current list of targets.
	     */
	    cp = line;
	    if (ch_isspace(line[0])) {
		pp_skip_whitespace(&cp);
		while (*cp && (ParseIsEscaped(line, cp) ||
			*cp != ':' && *cp != '!')) {
		    cp++;
		}
		if (*cp == '\0') {
		    if (targets == NULL) {
			Parse_Error(PARSE_WARNING,
				     "Shell command needs a leading tab");
			goto shellCommand;
		    }
		}
	    }
#endif
	    FinishDependencyGroup();

	    /*
	     * For some reason - probably to make the parser impossible -
	     * a ';' can be used to separate commands from dependencies.
	     * Attempt to avoid ';' inside substitution patterns.
	     */
	    {
		int level = 0;

		for (cp = line; *cp != 0; cp++) {
		    if (*cp == '\\' && cp[1] != 0) {
			cp++;
			continue;
		    }
		    if (*cp == '$' &&
			(cp[1] == '(' || cp[1] == '{')) {
			level++;
			continue;
		    }
		    if (level > 0) {
			if (*cp == ')' || *cp == '}') {
			    level--;
			    continue;
			}
		    } else if (*cp == ';') {
			break;
		    }
		}
	    }
	    if (*cp != 0)
		/* Terminate the dependency list at the ';' */
		*cp++ = 0;
	    else
		cp = NULL;

	    /*
	     * We now know it's a dependency line so it needs to have all
	     * variables expanded before being parsed.
	     *
	     * XXX: Ideally the dependency line would first be split into
	     * its left-hand side, dependency operator and right-hand side,
	     * and then each side would be expanded on its own.  This would
	     * allow for the left-hand side to allow only defined variables
	     * and to allow variables on the right-hand side to be undefined
	     * as well.
	     *
	     * Parsing the line first would also prevent that targets
	     * generated from variable expressions are interpreted as the
	     * dependency operator, such as in "target${:U:} middle: source",
	     * in which the middle is interpreted as a source, not a target.
	     */
	    {
	        /* In lint mode, allow undefined variables to appear in
	         * dependency lines.
	         *
	         * Ideally, only the right-hand side would allow undefined
	         * variables since it is common to have no dependencies.
	         * Having undefined variables on the left-hand side is more
	         * unusual though.  Since both sides are expanded in a single
	         * pass, there is not much choice what to do here.
	         *
	         * In normal mode, it does not matter whether undefined
	         * variables are allowed or not since as of 2020-09-14,
	         * Var_Parse does not print any parse errors in such a case.
	         * It simply returns the special empty string var_Error,
	         * which cannot be detected in the result of Var_Subst. */
		VarEvalFlags eflags = DEBUG(LINT)
				      ? VARE_WANTRES
				      : VARE_UNDEFERR|VARE_WANTRES;
		(void)Var_Subst(line, VAR_CMD, eflags, &line);
		/* TODO: handle errors */
	    }

	    /* Need a fresh list for the target nodes */
	    if (targets != NULL)
		Lst_Free(targets);
	    targets = Lst_Init();

	    ParseDoDependency(line);
	    free(line);

	    /* If there were commands after a ';', add them now */
	    if (cp != NULL) {
		goto shellCommand;
	    }
	}
	/*
	 * Reached EOF, but it may be just EOF of an include file...
	 */
    } while (ParseEOF() == CONTINUE);

    FinishDependencyGroup();

    if (fatals) {
	(void)fflush(stdout);
	(void)fprintf(stderr,
	    "%s: Fatal errors encountered -- cannot continue",
	    progname);
	PrintOnError(NULL, NULL);
	exit(1);
    }
}

/*-
 *---------------------------------------------------------------------
 * Parse_Init --
 *	initialize the parsing module
 *
 * Results:
 *	none
 *
 * Side Effects:
 *	the parseIncPath list is initialized...
 *---------------------------------------------------------------------
 */
void
Parse_Init(void)
{
    mainNode = NULL;
    parseIncPath = Lst_Init();
    sysIncPath = Lst_Init();
    defIncPath = Lst_Init();
    Stack_Init(&includes);
#ifdef CLEANUP
    targCmds = Lst_Init();
#endif
}

void
Parse_End(void)
{
#ifdef CLEANUP
    Lst_Destroy(targCmds, free);
    assert(targets == NULL);
    Lst_Destroy(defIncPath, Dir_Destroy);
    Lst_Destroy(sysIncPath, Dir_Destroy);
    Lst_Destroy(parseIncPath, Dir_Destroy);
    assert(Stack_IsEmpty(&includes));
    Stack_Done(&includes);
#endif
}


/*-
 *-----------------------------------------------------------------------
 * Parse_MainName --
 *	Return a Lst of the main target to create for main()'s sake. If
 *	no such target exists, we Punt with an obnoxious error message.
 *
 * Results:
 *	A Lst of the single node to create.
 *
 * Side Effects:
 *	None.
 *
 *-----------------------------------------------------------------------
 */
GNodeList *
Parse_MainName(void)
{
    GNodeList *mainList;

    mainList = Lst_Init();

    if (mainNode == NULL) {
	Punt("no target to make.");
	/*NOTREACHED*/
    } else if (mainNode->type & OP_DOUBLEDEP) {
	Lst_Append(mainList, mainNode);
	Lst_AppendAll(mainList, mainNode->cohorts);
    }
    else
	Lst_Append(mainList, mainNode);
    Var_Append(".TARGETS", mainNode->name, VAR_GLOBAL);
    return mainList;
}