initial import of NetBSD tree

1 files changed, 811 insertions, 0 deletions

diff --git a/usr.bin/sed/compile.c b/usr.bin/sed/compile.c
new file mode 100644
index 00000000000..79d40173266
--- /dev/null
+++ b/usr.bin/sed/compile.c
@@ -0,0 +1,811 @@
+/*-
+ * Copyright (c) 1992 Diomidis Spinellis.
+ * Copyright (c) 1992, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Diomidis Spinellis of Imperial College, University of London.
+ *
+ * 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.
+ */
+
+#ifndef lint
+/* from: static char sccsid[] = "@(#)compile.c	8.1 (Berkeley) 6/6/93"; */
+static char *rcsid = "$Id: compile.c,v 1.1 1995/10/18 08:46:05 deraadt Exp $";
+#endif /* not lint */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <regex.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "defs.h"
+#include "extern.h"
+
+#define LHSZ	128
+#define	LHMASK	(LHSZ - 1)
+static struct labhash {
+	struct	labhash *lh_next;
+	u_int	lh_hash;
+	struct	s_command *lh_cmd;
+	int	lh_ref;
+} *labels[LHSZ];
+
+static char	 *compile_addr __P((char *, struct s_addr *));
+static char	 *compile_ccl __P((char **, char *));
+static char	 *compile_delimited __P((char *, char *));
+static char	 *compile_flags __P((char *, struct s_subst *));
+static char	 *compile_re __P((char *, regex_t **));
+static char	 *compile_subst __P((char *, struct s_subst *));
+static char	 *compile_text __P((void));
+static char	 *compile_tr __P((char *, char **));
+static struct s_command
+		**compile_stream __P((struct s_command **));
+static char	 *duptoeol __P((char *, char *));
+static void	  enterlabel __P((struct s_command *));
+static struct s_command
+		 *findlabel __P((char *));
+static void	  fixuplabel __P((struct s_command *, struct s_command *));
+static void	  uselabel __P((void));
+
+/*
+ * Command specification.  This is used to drive the command parser.
+ */
+struct s_format {
+	char code;				/* Command code */
+	int naddr;				/* Number of address args */
+	enum e_args args;			/* Argument type */
+};
+
+static struct s_format cmd_fmts[] = {
+	{'{', 2, GROUP},
+	{'}', 0, ENDGROUP},
+	{'a', 1, TEXT},
+	{'b', 2, BRANCH},
+	{'c', 2, TEXT},
+	{'d', 2, EMPTY},
+	{'D', 2, EMPTY},
+	{'g', 2, EMPTY},
+	{'G', 2, EMPTY},
+	{'h', 2, EMPTY},
+	{'H', 2, EMPTY},
+	{'i', 1, TEXT},
+	{'l', 2, EMPTY},
+	{'n', 2, EMPTY},
+	{'N', 2, EMPTY},
+	{'p', 2, EMPTY},
+	{'P', 2, EMPTY},
+	{'q', 1, EMPTY},
+	{'r', 1, RFILE},
+	{'s', 2, SUBST},
+	{'t', 2, BRANCH},
+	{'w', 2, WFILE},
+	{'x', 2, EMPTY},
+	{'y', 2, TR},
+	{'!', 2, NONSEL},
+	{':', 0, LABEL},
+	{'#', 0, COMMENT},
+	{'=', 1, EMPTY},
+	{'\0', 0, COMMENT},
+};
+
+/* The compiled program. */
+struct s_command *prog;
+
+/*
+ * Compile the program into prog.
+ * Initialise appends.
+ */
+void
+compile()
+{
+	*compile_stream(&prog) = NULL;
+	fixuplabel(prog, NULL);
+	uselabel();
+	appends = xmalloc(sizeof(struct s_appends) * appendnum);
+	match = xmalloc((maxnsub + 1) * sizeof(regmatch_t));
+}
+
+#define EATSPACE() do {							\
+	if (p)								\
+		while (*p && isascii(*p) && isspace(*p))		\
+			p++;						\
+	} while (0)
+
+static struct s_command **
+compile_stream(link)
+	struct s_command **link;
+{
+	register char *p;
+	static char lbuf[_POSIX2_LINE_MAX + 1];	/* To save stack */
+	struct s_command *cmd, *cmd2, *stack;
+	struct s_format *fp;
+	int naddr;				/* Number of addresses */
+
+	stack = 0;
+	for (;;) {
+		if ((p = cu_fgets(lbuf, sizeof(lbuf))) == NULL) {
+			if (stack != 0)
+				err(COMPILE, "unexpected EOF (pending }'s)");
+			return (link);
+		}
+
+semicolon:	EATSPACE();
+		if (p && (*p == '#' || *p == '\0'))
+			continue;
+		*link = cmd = xmalloc(sizeof(struct s_command));
+		link = &cmd->next;
+		cmd->nonsel = cmd->inrange = 0;
+		/* First parse the addresses */
+		naddr = 0;
+
+/* Valid characters to start an address */
+#define	addrchar(c)	(strchr("0123456789/\\$", (c)))
+		if (addrchar(*p)) {
+			naddr++;
+			cmd->a1 = xmalloc(sizeof(struct s_addr));
+			p = compile_addr(p, cmd->a1);
+			EATSPACE();				/* EXTENSION */
+			if (*p == ',') {
+				p++;
+				EATSPACE();			/* EXTENSION */
+				naddr++;
+				cmd->a2 = xmalloc(sizeof(struct s_addr));
+				p = compile_addr(p, cmd->a2);
+				EATSPACE();
+			} else
+				cmd->a2 = 0;
+		} else
+			cmd->a1 = cmd->a2 = 0;
+
+nonsel:		/* Now parse the command */
+		if (!*p)
+			err(COMPILE, "command expected");
+		cmd->code = *p;
+		for (fp = cmd_fmts; fp->code; fp++)
+			if (fp->code == *p)
+				break;
+		if (!fp->code)
+			err(COMPILE, "invalid command code %c", *p);
+		if (naddr > fp->naddr)
+			err(COMPILE,
+"command %c expects up to %d address(es), found %d", *p, fp->naddr, naddr);
+		switch (fp->args) {
+		case NONSEL:			/* ! */
+			p++;
+			EATSPACE();
+			cmd->nonsel = ! cmd->nonsel;
+			goto nonsel;
+		case GROUP:			/* { */
+			p++;
+			EATSPACE();
+			cmd->next = stack;
+			stack = cmd;
+			link = &cmd->u.c;
+			if (*p)
+				goto semicolon;
+			break;
+		case ENDGROUP:
+			/*
+			 * Short-circuit command processing, since end of
+			 * group is really just a noop.
+			 */
+			cmd->nonsel = 1;
+			if (stack == 0)
+				err(COMPILE, "unexpected }");
+			cmd2 = stack;
+			stack = cmd2->next;
+			cmd2->next = cmd;
+			/*FALLTHROUGH*/
+		case EMPTY:		/* d D g G h H l n N p P q x = \0 */
+			p++;
+			EATSPACE();
+			if (*p == ';') {
+				p++;
+				link = &cmd->next;
+				goto semicolon;
+			}
+			if (*p)
+				err(COMPILE,
+"extra characters at the end of %c command", cmd->code);
+			break;
+		case TEXT:			/* a c i */
+			p++;
+			EATSPACE();
+			if (*p != '\\')
+				err(COMPILE,
+"command %c expects \\ followed by text", cmd->code);
+			p++;
+			EATSPACE();
+			if (*p)
+				err(COMPILE,
+"extra characters after \\ at the end of %c command", cmd->code);
+			cmd->t = compile_text();
+			break;
+		case COMMENT:			/* \0 # */
+			break;
+		case WFILE:			/* w */
+			p++;
+			EATSPACE();
+			if (*p == '\0')
+				err(COMPILE, "filename expected");
+			cmd->t = duptoeol(p, "w command");
+			if (aflag)
+				cmd->u.fd = -1;
+			else if ((cmd->u.fd = open(p, 
+			    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC,
+			    DEFFILEMODE)) == -1)
+				err(FATAL, "%s: %s\n", p, strerror(errno));
+			break;
+		case RFILE:			/* r */
+			p++;
+			EATSPACE();
+			if (*p == '\0')
+				err(COMPILE, "filename expected");
+			else
+				cmd->t = duptoeol(p, "read command");
+			break;
+		case BRANCH:			/* b t */
+			p++;
+			EATSPACE();
+			if (*p == '\0')
+				cmd->t = NULL;
+			else
+				cmd->t = duptoeol(p, "branch");
+			break;
+		case LABEL:			/* : */
+			p++;
+			EATSPACE();
+			cmd->t = duptoeol(p, "label");
+			if (strlen(p) == 0)
+				err(COMPILE, "empty label");
+			enterlabel(cmd);
+			break;
+		case SUBST:			/* s */
+			p++;
+			if (*p == '\0' || *p == '\\')
+				err(COMPILE,
+"substitute pattern can not be delimited by newline or backslash");
+			cmd->u.s = xmalloc(sizeof(struct s_subst));
+			p = compile_re(p, &cmd->u.s->re);
+			if (p == NULL)
+				err(COMPILE, "unterminated substitute pattern");
+			--p;
+			p = compile_subst(p, cmd->u.s);
+			p = compile_flags(p, cmd->u.s);
+			EATSPACE();
+			if (*p == ';') {
+				p++;
+				link = &cmd->next;
+				goto semicolon;
+			}
+			break;
+		case TR:			/* y */
+			p++;
+			p = compile_tr(p, (char **)&cmd->u.y);
+			EATSPACE();
+			if (*p == ';') {
+				p++;
+				link = &cmd->next;
+				goto semicolon;
+			}
+			if (*p)
+				err(COMPILE,
+"extra text at the end of a transform command");
+			break;
+		}
+	}
+}
+
+/*
+ * Get a delimited string.  P points to the delimeter of the string; d points
+ * to a buffer area.  Newline and delimiter escapes are processed; other
+ * escapes are ignored.
+ *
+ * Returns a pointer to the first character after the final delimiter or NULL
+ * in the case of a non-terminated string.  The character array d is filled
+ * with the processed string.
+ */
+static char *
+compile_delimited(p, d)
+	char *p, *d;
+{
+	char c;
+
+	c = *p++;
+	if (c == '\0')
+		return (NULL);
+	else if (c == '\\')
+		err(COMPILE, "\\ can not be used as a string delimiter");
+	else if (c == '\n')
+		err(COMPILE, "newline can not be used as a string delimiter");
+	while (*p) {
+		if (*p == '[') {
+			if ((d = compile_ccl(&p, d)) == NULL)
+				err(COMPILE, "unbalanced brackets ([])");
+			continue;
+		} else if (*p == '\\' && p[1] == '[') {
+			*d++ = *p++;
+		} else if (*p == '\\' && p[1] == c)
+			p++;
+		else if (*p == '\\' && p[1] == 'n') {
+			*d++ = '\n';
+			p += 2;
+			continue;
+		} else if (*p == '\\' && p[1] == '\\')
+			*d++ = *p++;
+		else if (*p == c) {
+			*d = '\0';
+			return (p + 1);
+		}
+		*d++ = *p++;
+	}
+	return (NULL);
+}
+
+
+/* compile_ccl: expand a POSIX character class */
+static char *
+compile_ccl(sp, t)
+	char **sp;
+	char *t;
+{
+	int c, d;
+	char *s = *sp;
+
+	*t++ = *s++;
+	if (*s == '^')
+		*t++ = *s++;
+	if (*s == ']')
+		*t++ = *s++;
+	for (; *s && (*t = *s) != ']'; s++, t++)
+		if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '=')) {
+			*++t = *++s, t++, s++;
+			for (c = *s; (*t = *s) != ']' || c != d; s++, t++)
+				if ((c = *s) == '\0')
+					return NULL;
+		} else if (*s == '\\' && s[1] == 'n')
+			    *t = '\n', s++;
+	return (*s == ']') ? *sp = ++s, ++t : NULL;
+}
+
+/*
+ * Get a regular expression.  P points to the delimiter of the regular
+ * expression; repp points to the address of a regexp pointer.  Newline
+ * and delimiter escapes are processed; other escapes are ignored.
+ * Returns a pointer to the first character after the final delimiter
+ * or NULL in the case of a non terminated regular expression.  The regexp
+ * pointer is set to the compiled regular expression.
+ * Cflags are passed to regcomp.
+ */
+static char *
+compile_re(p, repp)
+	char *p;
+	regex_t **repp;
+{
+	int eval;
+	char re[_POSIX2_LINE_MAX + 1];
+
+	p = compile_delimited(p, re);
+	if (p && strlen(re) == 0) {
+		*repp = NULL;
+		return (p);
+	}
+	*repp = xmalloc(sizeof(regex_t));
+	if (p && (eval = regcomp(*repp, re, 0)) != 0)
+		err(COMPILE, "RE error: %s", strregerror(eval, *repp));
+	if (maxnsub < (*repp)->re_nsub)
+		maxnsub = (*repp)->re_nsub;
+	return (p);
+}
+
+/*
+ * Compile the substitution string of a regular expression and set res to
+ * point to a saved copy of it.  Nsub is the number of parenthesized regular
+ * expressions.
+ */
+static char *
+compile_subst(p, s)
+	char *p;
+	struct s_subst *s;
+{
+	static char lbuf[_POSIX2_LINE_MAX + 1];
+	int asize, ref, size;
+	char c, *text, *op, *sp;
+
+	c = *p++;			/* Terminator character */
+	if (c == '\0')
+		return (NULL);
+
+	s->maxbref = 0;
+	s->linenum = linenum;
+	asize = 2 * _POSIX2_LINE_MAX + 1;
+	text = xmalloc(asize);
+	size = 0;
+	do {
+		op = sp = text + size;
+		for (; *p; p++) {
+			if (*p == '\\') {
+				p++;
+				if (strchr("123456789", *p) != NULL) {
+					*sp++ = '\\';
+					ref = *p - '0';
+					if (s->re != NULL &&
+					    ref > s->re->re_nsub)
+						err(COMPILE,
+"\\%c not defined in the RE", *p);
+					if (s->maxbref < ref)
+						s->maxbref = ref;
+				} else if (*p == '&' || *p == '\\')
+					*sp++ = '\\';
+			} else if (*p == c) {
+				p++;
+				*sp++ = '\0';
+				size += sp - op;
+				s->new = xrealloc(text, size);
+				return (p);
+			} else if (*p == '\n') {
+				err(COMPILE,
+"unescaped newline inside substitute pattern");
+				/* NOTREACHED */
+			}
+			*sp++ = *p;
+		}
+		size += sp - op;
+		if (asize - size < _POSIX2_LINE_MAX + 1) {
+			asize *= 2;
+			text = xmalloc(asize);
+		}
+	} while (cu_fgets(p = lbuf, sizeof(lbuf)));
+	err(COMPILE, "unterminated substitute in regular expression");
+	/* NOTREACHED */
+}
+
+/*
+ * Compile the flags of the s command
+ */
+static char *
+compile_flags(p, s)
+	char *p;
+	struct s_subst *s;
+{
+	int gn;			/* True if we have seen g or n */
+	char wfile[_POSIX2_LINE_MAX + 1], *q;
+
+	s->n = 1;				/* Default */
+	s->p = 0;
+	s->wfile = NULL;
+	s->wfd = -1;
+	for (gn = 0;;) {
+		EATSPACE();			/* EXTENSION */
+		switch (*p) {
+		case 'g':
+			if (gn)
+				err(COMPILE,
+"more than one number or 'g' in substitute flags");
+			gn = 1;
+			s->n = 0;
+			break;
+		case '\0':
+		case '\n':
+		case ';':
+			return (p);
+		case 'p':
+			s->p = 1;
+			break;
+		case '1': case '2': case '3':
+		case '4': case '5': case '6':
+		case '7': case '8': case '9':
+			if (gn)
+				err(COMPILE,
+"more than one number or 'g' in substitute flags");
+			gn = 1;
+			/* XXX Check for overflow */
+			s->n = (int)strtol(p, &p, 10);
+			break;
+		case 'w':
+			p++;
+#ifdef HISTORIC_PRACTICE
+			if (*p != ' ') {
+				err(WARNING, "space missing before w wfile");
+				return (p);
+			}
+#endif
+			EATSPACE();
+			q = wfile;
+			while (*p) {
+				if (*p == '\n')
+					break;
+				*q++ = *p++;
+			}
+			*q = '\0';
+			if (q == wfile)
+				err(COMPILE, "no wfile specified");
+			s->wfile = strdup(wfile);
+			if (!aflag && (s->wfd = open(wfile,
+			    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC,
+			    DEFFILEMODE)) == -1)
+				err(FATAL, "%s: %s\n", wfile, strerror(errno));
+			return (p);
+		default:
+			err(COMPILE,
+			    "bad flag in substitute command: '%c'", *p);
+			break;
+		}
+		p++;
+	}
+}
+
+/*
+ * Compile a translation set of strings into a lookup table.
+ */
+static char *
+compile_tr(p, transtab)
+	char *p;
+	char **transtab;
+{
+	int i;
+	char *lt, *op, *np;
+	char old[_POSIX2_LINE_MAX + 1];
+	char new[_POSIX2_LINE_MAX + 1];
+
+	if (*p == '\0' || *p == '\\')
+		err(COMPILE,
+"transform pattern can not be delimited by newline or backslash");
+	p = compile_delimited(p, old);
+	if (p == NULL) {
+		err(COMPILE, "unterminated transform source string");
+		return (NULL);
+	}
+	p = compile_delimited(--p, new);
+	if (p == NULL) {
+		err(COMPILE, "unterminated transform target string");
+		return (NULL);
+	}
+	EATSPACE();
+	if (strlen(new) != strlen(old)) {
+		err(COMPILE, "transform strings are not the same length");
+		return (NULL);
+	}
+	/* We assume characters are 8 bits */
+	lt = xmalloc(UCHAR_MAX);
+	for (i = 0; i <= UCHAR_MAX; i++)
+		lt[i] = (char)i;
+	for (op = old, np = new; *op; op++, np++)
+		lt[(u_char)*op] = *np;
+	*transtab = lt;
+	return (p);
+}
+
+/*
+ * Compile the text following an a or i command.
+ */
+static char *
+compile_text()
+{
+	int asize, size;
+	char *text, *p, *op, *s;
+	char lbuf[_POSIX2_LINE_MAX + 1];
+
+	asize = 2 * _POSIX2_LINE_MAX + 1;
+	text = xmalloc(asize);
+	size = 0;
+	while (cu_fgets(lbuf, sizeof(lbuf))) {
+		op = s = text + size;
+		p = lbuf;
+		EATSPACE();
+		for (; *p; p++) {
+			if (*p == '\\')
+				p++;
+			*s++ = *p;
+		}
+		size += s - op;
+		if (p[-2] != '\\') {
+			*s = '\0';
+			break;
+		}
+		if (asize - size < _POSIX2_LINE_MAX + 1) {
+			asize *= 2;
+			text = xmalloc(asize);
+		}
+	}
+	return (xrealloc(text, size + 1));
+}
+
+/*
+ * Get an address and return a pointer to the first character after
+ * it.  Fill the structure pointed to according to the address.
+ */
+static char *
+compile_addr(p, a)
+	char *p;
+	struct s_addr *a;
+{
+	char *end;
+
+	switch (*p) {
+	case '\\':				/* Context address */
+		++p;
+		/* FALLTHROUGH */
+	case '/':				/* Context address */
+		p = compile_re(p, &a->u.r);
+		if (p == NULL)
+			err(COMPILE, "unterminated regular expression");
+		a->type = AT_RE;
+		return (p);
+
+	case '$':				/* Last line */
+		a->type = AT_LAST;
+		return (p + 1);
+						/* Line number */
+	case '0': case '1': case '2': case '3': case '4': 
+	case '5': case '6': case '7': case '8': case '9':
+		a->type = AT_LINE;
+		a->u.l = strtol(p, &end, 10);
+		return (end);
+	default:
+		err(COMPILE, "expected context address");
+		return (NULL);
+	}
+}
+
+/*
+ * duptoeol --
+ *	Return a copy of all the characters up to \n or \0.
+ */
+static char *
+duptoeol(s, ctype)
+	register char *s;
+	char *ctype;
+{
+	size_t len;
+	int ws;
+	char *start;
+
+	ws = 0;
+	for (start = s; *s != '\0' && *s != '\n'; ++s)
+		ws = isspace(*s);
+	*s = '\0';
+	if (ws)
+		err(WARNING, "whitespace after %s", ctype);
+	len = s - start + 1;
+	return (memmove(xmalloc(len), start, len));
+}
+
+/*
+ * Convert goto label names to addresses, and count a and r commands, in
+ * the given subset of the script.  Free the memory used by labels in b
+ * and t commands (but not by :).
+ *
+ * TODO: Remove } nodes
+ */
+static void
+fixuplabel(cp, end)
+	struct s_command *cp, *end;
+{
+
+	for (; cp != end; cp = cp->next)
+		switch (cp->code) {
+		case 'a':
+		case 'r':
+			appendnum++;
+			break;
+		case 'b':
+		case 't':
+			/* Resolve branch target. */
+			if (cp->t == NULL) {
+				cp->u.c = NULL;
+				break;
+			}
+			if ((cp->u.c = findlabel(cp->t)) == NULL)
+				err(COMPILE2, "undefined label '%s'", cp->t);
+			free(cp->t);
+			break;
+		case '{':
+			/* Do interior commands. */
+			fixuplabel(cp->u.c, cp->next);
+			break;
+		}
+}
+
+/*
+ * Associate the given command label for later lookup.
+ */
+static void
+enterlabel(cp)
+	struct s_command *cp;
+{
+	register struct labhash **lhp, *lh;
+	register u_char *p;
+	register u_int h, c;
+
+	for (h = 0, p = (u_char *)cp->t; (c = *p) != 0; p++)
+		h = (h << 5) + h + c;
+	lhp = &labels[h & LHMASK];
+	for (lh = *lhp; lh != NULL; lh = lh->lh_next)
+		if (lh->lh_hash == h && strcmp(cp->t, lh->lh_cmd->t) == 0)
+			err(COMPILE2, "duplicate label '%s'", cp->t);
+	lh = xmalloc(sizeof *lh);
+	lh->lh_next = *lhp;
+	lh->lh_hash = h;
+	lh->lh_cmd = cp;
+	lh->lh_ref = 0;
+	*lhp = lh;
+}
+
+/*
+ * Find the label contained in the command l in the command linked
+ * list cp.  L is excluded from the search.  Return NULL if not found.
+ */
+static struct s_command *
+findlabel(name)
+	char *name;
+{
+	register struct labhash *lh;
+	register u_char *p;
+	register u_int h, c;
+
+	for (h = 0, p = (u_char *)name; (c = *p) != 0; p++)
+		h = (h << 5) + h + c;
+	for (lh = labels[h & LHMASK]; lh != NULL; lh = lh->lh_next) {
+		if (lh->lh_hash == h && strcmp(name, lh->lh_cmd->t) == 0) {
+			lh->lh_ref = 1;
+			return (lh->lh_cmd);
+		}
+	}
+	return (NULL);
+}
+
+/* 
+ * Warn about any unused labels.  As a side effect, release the label hash
+ * table space.
+ */
+static void
+uselabel()
+{
+	register struct labhash *lh, *next;
+	register int i;
+
+	for (i = 0; i < LHSZ; i++) {
+		for (lh = labels[i]; lh != NULL; lh = next) {
+			next = lh->lh_next;
+			if (!lh->lh_ref)
+				err(WARNING, "unused label '%s'",
+				    lh->lh_cmd->t);
+			free(lh);
+		}
+	}
+}