===================================================================
RCS file: /cvs/docbook2mdoc/parse.c,v
retrieving revision 1.23
retrieving revision 1.24
diff -u -p -r1.23 -r1.24
--- docbook2mdoc/parse.c	2019/04/08 14:37:31	1.23
+++ docbook2mdoc/parse.c	2019/04/08 22:47:34	1.24
@@ -1,4 +1,4 @@
-/* $Id: parse.c,v 1.23 2019/04/08 14:37:31 schwarze Exp $ */
+/* $Id: parse.c,v 1.24 2019/04/08 22:47:34 schwarze Exp $ */
 /*
  * Copyright (c) 2014 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2019 Ingo Schwarze <schwarze@openbsd.org>
@@ -17,6 +17,9 @@
  */
 #include <assert.h>
 #include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <libgen.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -273,6 +276,7 @@ static	const struct entity entities[] = {
 
 static size_t	 parse_string(struct parse *, char *, size_t,
 			 enum pstate *, int);
+static void	 parse_fd(struct parse *, int);
 
 
 static void
@@ -957,8 +961,18 @@ parse_string(struct parse *p, char *b, size_t rlen,
 	return poff;
 }
 
-struct ptree *
-parse_file(struct parse *p, int fd, const char *fname)
+
+/*
+ * The read loop.
+ * If the previous token was incomplete and asked for more input,
+ * we have to enter the read loop once more even on EOF.
+ * Once rsz is 0, incomplete tokens will no longer ask for more input
+ * but instead use whatever there is, and then exit the read loop.
+ * The minus one on the size limit for read(2) is needed such that
+ * advance() can set b[rlen] to NUL when needed.
+ */
+static void
+parse_fd(struct parse *p, int fd)
 {
 	char		 b[4096];
 	ssize_t		 rsz;	/* Return value from read(2). */
@@ -966,24 +980,8 @@ parse_file(struct parse *p, int fd, const char *fname)
 	size_t		 poff;  /* Parse offset in b[]. */
 	enum pstate	 pstate;
 
-	p->fname = fname;
-	p->nline = 1;
-	p->ncol = 1;
-	pstate = PARSE_ELEM;
 	rlen = 0;
-
-	/*
-	 * Read loop.
-	 *
-         * If the previous token was incomplete and asked for more
-         * input, we have to enter the read loop once more even on EOF.
-	 * Once rsz is 0, incomplete tokens will no longer ask
-	 * for more input but instead use whatever there is,
-	 * and then exit the read loop.
-	 * The minus one on the size limit for read(2) is needed
-	 * such that advance() can set b[rlen] to NUL when needed.
-	 */
-
+	pstate = PARSE_ELEM;
 	while ((rsz = read(fd, b + rlen, sizeof(b) - rlen - 1)) >= 0 &&
 	    (rlen += rsz) > 0) {
 		poff = parse_string(p, b, rlen, &pstate, rsz > 0);
@@ -992,13 +990,70 @@ parse_file(struct parse *p, int fd, const char *fname)
 		rlen -= poff;
 		memmove(b, b + poff, rlen);
 	}
-	if (rsz < 0) {
-		perror(fname);
-		p->tree->flags |= TREE_FAIL;
+	if (rsz < 0)
+		error_msg(p, "read: %s", strerror(errno));
+}
+
+/*
+ * Open and parse a file.
+ */
+struct ptree *
+parse_file(struct parse *p, int fd, const char *fname)
+{
+	const char	*save_fname;
+	int		 save_line, save_col;
+
+	/* Save and initialize reporting data. */
+
+	save_fname = p->fname;
+	save_line = p->nline;
+	save_col = p->ncol;
+	p->fname = fname;
+	p->line = 0;
+	p->col = 0;
+
+	/* Open the file, unless it is already open. */
+
+	if (fd == -1 && (fd = open(fname, O_RDONLY, 0)) == -1) {
+		error_msg(p, "open: %s", strerror(errno));
+		p->fname = save_fname;
+		return p->tree;
 	}
-	pnode_closetext(p);
-	if ((p->tree->flags & TREE_CLOSED) == 0)
-		warn_msg(p, "document not closed");
-	pnode_unlink(p->doctype);
+
+	/*
+	 * After opening the starting file, change to the directory it
+	 * is located in, in case it wants to include any further files,
+	 * which are typically given with relative paths in DocBook.
+	 * Do this on a best-effort basis; don't complain about failure.
+	 */
+
+	if (save_fname == NULL && (fname = dirname(fname)) != NULL &&
+	    strcmp(fname, ".") != 0)
+		(void)chdir(fname);
+
+	/* Run the read loop. */
+
+	p->nline = 1;
+	p->ncol = 1;
+	parse_fd(p, fd);
+
+	/* On the top level, finalize the parse tree. */
+
+	if (save_fname == NULL) {
+		pnode_closetext(p);
+		if (p->tree->root == NULL)
+			error_msg(p, "empty document");
+		else if ((p->tree->flags & TREE_CLOSED) == 0)
+			warn_msg(p, "document not closed");
+		pnode_unlink(p->doctype);
+	}
+
+	/* Clean up. */
+
+	if (fd != STDIN_FILENO)
+		close(fd);
+	p->fname = save_fname;
+	p->nline = save_line;
+	p->ncol = save_col;
 	return p->tree;
 }