From 42ad13ca342ae47b39d9a825ef4cd4341a438fd6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niels=20M=C3=B6ller?= <nisse@lysator.liu.se>
Date: Mon, 4 Mar 2002 21:39:57 +0100
Subject: [PATCH] New files. A lexer and a recursive-descent parser for config
files.
Rev: src/parse_config.c:1.1
Rev: src/parse_config.h:1.1
---
src/parse_config.c | 356 +++++++++++++++++++++++++++++++++++++++++++++
src/parse_config.h | 55 +++++++
2 files changed, 411 insertions(+)
create mode 100644 src/parse_config.c
create mode 100644 src/parse_config.h
diff --git a/src/parse_config.c b/src/parse_config.c
new file mode 100644
index 000000000..ee17f7640
--- /dev/null
+++ b/src/parse_config.c
@@ -0,0 +1,356 @@
+/* parse_config.c
+ *
+ * $id$
+ *
+ * Parsing of configuration files. */
+
+#include "parse_config.h"
+
+#include "format.h"
+#include "parse.h"
+#include "werror.h"
+#include "xalloc.h"
+
+#include <assert.h>
+#include <string.h>
+
+#define BUFFER (&(self->buffer))
+
+#include "parse_macros.h"
+
+#include "parse_config.c.x"
+
+/* GABA:
+ (class
+ (name config_setting)
+ (vars
+ (next object config_setting)
+ (type . "enum config_type")
+ (value string)))
+*/
+
+/* GABA:
+ (class
+ (name config_host)
+ (vars
+ (next object config_host)
+ (name string)
+ (settings object config_setting)))
+*/
+
+/* GABA:
+ (class
+ (name config_group)
+ (vars
+ (next object config_group)
+ (name string)
+ ; Group settings
+ (settings object config_setting)
+ (hosts object config_host)))
+*/
+
+enum token_type
+ { TOK_EOF, TOK_BEGIN_GROUP, TOK_END_GROUP, TOK_STRING, TOK_ERROR };
+
+/* FIXME: Keep track of linenumber */
+struct tokenizer
+{
+ struct simple_buffer buffer;
+ enum token_type type;
+ unsigned token_length;
+ const char *token;
+};
+
+static void
+tokenizer_init(struct tokenizer *self,
+ unsigned length, const unsigned char *data)
+{
+ simple_buffer_init(&self->buffer, length, data);
+}
+
+static enum token_type
+next_token(struct tokenizer *self)
+{
+ /* FIXME: Share a char-class table with sexp_parser.c. */
+ static const char char_class[0x100] =
+ {
+ /* HT, LF, VT, FF, CR */
+ 0,0,0,0,0,0,0,0,0,1,1,1,1,1,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+ /* SPACE */
+ 1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+ /* '{', '}' */
+ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,2,0,2,0,0,
+
+ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+ };
+#define IS_SPACE(c) (char_class[c] & 1)
+#define IS_SEPARATOR(c) (char_class[c] & 3)
+ while (LEFT && IS_SPACE(*HERE))
+ ADVANCE(1);
+
+ if (!LEFT)
+ self->type = TOK_EOF;
+ else switch(*HERE)
+ {
+ case '{':
+ self->type = TOK_BEGIN_GROUP;
+ ADVANCE(1);
+ break;
+ case '}':
+ self->type = TOK_END_GROUP;
+ ADVANCE(1);
+ break;
+ default:
+ {
+ unsigned i;
+ self->token = HERE;
+
+ for (i = 0; i<LEFT && !IS_SEPARATOR(HERE[i]); i++)
+ ;
+ self->token_length = i;
+ ADVANCE(i);
+ }
+ }
+ return self->type;
+}
+
+/* Can only be called if self->type == TOK_STRING */
+static int
+looking_at(struct tokenizer *self, const char *word)
+{
+ unsigned length = strlen(word);
+
+ return (length == self->token_length
+ && !memcmp(self->token, word, length));
+}
+
+static struct lsh_string *
+parse_word(struct tokenizer *self)
+{
+ struct lsh_string *s;
+ if (self->type != TOK_STRING)
+ return NULL;
+
+ s = ssh_format("%ls", self->token_length, self->token);
+ next_token(self);
+ return s;
+}
+
+static struct config_setting *
+parse_setting(struct tokenizer *self, struct config_setting *settings)
+{
+ struct lsh_string *s;
+ enum config_type type;
+ if (looking_at(self, "address"))
+ type = CONFIG_ADDRESS;
+ else if (looking_at(self, "user"))
+ type = CONFIG_USER;
+ else
+ return NULL;
+
+ next_token(self);
+ s = parse_word(self);
+ if (!s)
+ return NULL;
+
+ {
+ /* Push new object on the list */
+ NEW(config_setting, n);
+ n->next = settings;
+ settings = n;
+ }
+
+ settings->type = type;
+ settings->value = s;
+
+ return settings;
+}
+
+static struct config_setting *
+parse_host_settings(struct tokenizer *self)
+{
+ struct config_setting *settings = NULL;
+
+ while (self->type == TOK_STRING)
+ {
+ settings = parse_setting(self, settings);
+ if (!settings)
+ return NULL;
+ }
+ return settings;
+}
+
+static int
+parse_token(struct tokenizer *self, enum token_type type)
+{
+ if (self->type == type)
+ {
+ next_token(self);
+ return 1;
+ }
+ else
+ return 0;
+}
+
+static struct config_host *
+parse_hosts(struct tokenizer *self, struct config_host *hosts)
+{
+ while (self->type == TOK_STRING)
+ {
+ {
+ /* Push new object on the list */
+ NEW(config_host, n);
+ n->next = hosts;
+ hosts = n;
+ }
+ hosts->name = parse_word(self);
+ assert(hosts->name);
+ if (self->type == TOK_BEGIN_GROUP)
+ {
+ hosts->settings = parse_host_settings(self);
+ if (!parse_token(self, TOK_END_GROUP))
+ return NULL;
+ }
+ }
+ return hosts;
+}
+
+#if 0
+static struct config_setting *
+parse_group(struct tokenizer *self)
+{
+ struct config_setting *settings = NULL;
+
+ while (self->type == TOK_STRING)
+ {
+ struct lsh_string *s;
+ {
+ /* Push new object on the list */
+ NEW(config_setting, n);
+ n->next = settings;
+ settings = n;
+ }
+ if (looking_at(self, "address"))
+ settings->type = CONFIG_ADDRESS;
+ else if (looking_at(self, "user"))
+ settings->type = CONFIG_USER;
+ else if (looking_at(self, "hosts"))
+
+ else
+ return NULL;
+
+ next_token(self);
+ if (self->type != TOK_STRING)
+ return NULL;
+
+ s = parse_word(self);
+ if (!s)
+ return NULL;
+ settings->value = s;
+ }
+ return settings;
+}
+#endif
+
+static struct config_group *
+parse_groups(struct tokenizer *self)
+{
+ struct config_group *groups = NULL;
+ while (self->type != TOK_EOF)
+ {
+ {
+ /* Push new object on the list */
+ NEW(config_group, n);
+ n->next = groups;
+ groups = n;
+ }
+ /* Name is optional */
+ groups->name = parse_word(self);
+ groups->settings = NULL;
+ groups->hosts = NULL;
+
+ if (!parse_token(self, TOK_BEGIN_GROUP))
+ return NULL;
+
+ while (self->type != TOK_END_GROUP)
+ {
+ if (looking_at(self, "hosts"))
+ {
+ groups->hosts = parse_hosts(self, groups->hosts);
+ if (!groups->hosts)
+ return NULL;
+ }
+ else
+ {
+ groups->settings = parse_setting(self, groups->settings);
+ if (!groups->settings)
+ return NULL;
+ }
+ }
+ if (!parse_token(self, TOK_END_GROUP))
+ return NULL;
+ }
+ return groups;
+}
+
+struct config_group *
+config_parse_string(const struct lsh_string *s)
+{
+ struct tokenizer t;
+ tokenizer_init(&t, s->length, s->data);
+ next_token(&t);
+
+ return parse_groups(&t);
+}
+
+
+int
+config_lookup_host(const struct config_group *groups,
+ const char *host,
+ struct config_match *match)
+{
+ unsigned length = strlen(host);
+ int found = 0;
+
+ for (; groups; groups = groups->next)
+ {
+ const struct config_host *hosts;
+ for (hosts = groups->hosts; hosts; hosts = hosts->next)
+ if (lsh_string_eq_l(hosts->name, length, host))
+ {
+ if (found)
+ {
+ werror("Ambigous host name `%z' in configuration.\n");
+ return 1;
+ }
+ else
+ {
+ found = 1;
+ match->group = groups->settings;
+ match->host = hosts->settings;
+ }
+ }
+ }
+ return found;
+}
+
+const struct lsh_string *
+config_get_setting(enum config_type type,
+ const struct config_match *match)
+{
+ const struct config_setting *p;
+
+ for (p = match->host; p; p = p->next)
+ if (p->type == type)
+ return p->value;
+
+ for (p = match->group; p; p = p->next)
+ if (p->type == type)
+ return p->value;
+
+ return NULL;
+}
diff --git a/src/parse_config.h b/src/parse_config.h
new file mode 100644
index 000000000..07aef6e39
--- /dev/null
+++ b/src/parse_config.h
@@ -0,0 +1,55 @@
+/* parse_config.h
+ *
+ * $id$
+ *
+ * Parsing of configuration files. */
+
+/* lsh, an implementation of the ssh protocol
+ *
+ * Copyright (C) 2002 Niels M�ller
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef LSH_PARSE_CONFIG_H_INCLUDED
+#define LSH_PARSE_CONFIG_H_INCLUDED
+
+#include "lsh.h"
+
+enum config_type
+ { CONFIG_ADDRESS, CONFIG_USER };
+
+struct config_setting;
+struct config_group;
+
+struct config_group *
+config_parse_string(const struct lsh_string *s);
+
+struct config_match
+{
+ const struct config_setting *group;
+ const struct config_setting *host;
+};
+
+int
+config_lookup_host(const struct config_group *config,
+ const char *host,
+ struct config_match *match);
+
+const struct lsh_string *
+config_get_setting(enum config_type type,
+ const struct config_match *match);
+
+#endif /* LSH_PARSE_CONFIG_H_INCLUDED */
--
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