From 4d62bdd636e7dff1f9a72c794ef20fe0f5514772 Mon Sep 17 00:00:00 2001
From: Pavel Tvrdik <pawel.tvrdik@gmail.com>
Date: Fri, 11 Nov 2016 18:40:03 +0100
Subject: [PATCH] Parser: Display token where parser fell down

For example I misspelled device protocol
  bird: bird.conf, line 11 (nearby 'demice'): syntax error

It would be better to display whole err line. We can read it from
config->err_file_name again and display the line at config->err_lino.
---
 conf/conf.c        | 3 +++
 conf/conf.h        | 1 +
 nest/cli.c         | 2 +-
 sysdep/unix/main.c | 6 +++---
 4 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/conf/conf.c b/conf/conf.c
index 885e2e7e..80bf6b8b 100644
--- a/conf/conf.c
+++ b/conf/conf.c
@@ -61,6 +61,8 @@ static jmp_buf conf_jmpbuf;
 
 struct config *config, *new_config;
 
+char *cf_text;				/* Actual position from parser */
+
 static struct config *old_config;	/* Old configuration */
 static struct config *future_config;	/* New config held here if recon requested during recon */
 static int old_cftype;			/* Type of transition old_config -> config (RECONFIG_SOFT/HARD) */
@@ -511,6 +513,7 @@ cf_error(const char *msg, ...)
     strcpy(buf, "<bug: error message too long>");
   va_end(args);
   new_config->err_msg = cfg_strdup(buf);
+  new_config->err_token = cfg_strdup(cf_text);
   new_config->err_lino = ifs->lino;
   new_config->err_file_name = ifs->file_name;
   cf_lex_unwind();
diff --git a/conf/conf.h b/conf/conf.h
index f174d352..ab940033 100644
--- a/conf/conf.h
+++ b/conf/conf.h
@@ -49,6 +49,7 @@ struct config {
   int err_lino;				/* Line containing error */
   char *err_file_name;			/* File name containing error */
   char *file_name;			/* Name of main configuration file */
+  char *err_token;			/* Token where parser fell down */
   int file_fd;				/* File descriptor of main configuration file */
   HASH(struct symbol) sym_hash;		/* Lexer: symbol hash table */
   struct config *fallback;		/* Link to regular config for CLI parsing */
diff --git a/nest/cli.c b/nest/cli.c
index c421cc7e..148a626c 100644
--- a/nest/cli.c
+++ b/nest/cli.c
@@ -270,7 +270,7 @@ cli_command(struct cli *c)
   lp_flush(c->parser_pool);
   res = cli_parse(&f);
   if (!res)
-    cli_printf(c, 9001, f.err_msg);
+    cli_printf(c, 9001, "Bad command (nearby '%s'): %s", f.err_token, f.err_msg);
 
   config_free(&f);
 }
diff --git a/sysdep/unix/main.c b/sysdep/unix/main.c
index ea1476e7..dcfb9b4b 100644
--- a/sysdep/unix/main.c
+++ b/sysdep/unix/main.c
@@ -213,7 +213,7 @@ read_config(void)
   if (!unix_read_config(&conf, config_name))
     {
       if (conf->err_msg)
-	die("%s, line %d: %s", conf->err_file_name, conf->err_lino, conf->err_msg);
+	die("%s, line %d (nearby '%s'): %s", conf->err_file_name, conf->err_lino, conf->err_token, conf->err_msg);
       else
 	die("Unable to open configuration file %s: %m", config_name);
     }
@@ -230,7 +230,7 @@ async_config(void)
   if (!unix_read_config(&conf, config_name))
     {
       if (conf->err_msg)
-	log(L_ERR "%s, line %d: %s", conf->err_file_name, conf->err_lino, conf->err_msg);
+	log(L_ERR "%s, line %d (nearby '%s'): %s", conf->err_file_name, conf->err_lino, conf->err_token, conf->err_msg);
       else
 	log(L_ERR "Unable to open configuration file %s: %m", config_name);
       config_free(conf);
@@ -251,7 +251,7 @@ cmd_read_config(char *name)
   if (!unix_read_config(&conf, name))
     {
       if (conf->err_msg)
-	cli_msg(8002, "%s, line %d: %s", conf->err_file_name, conf->err_lino, conf->err_msg);
+	cli_msg(8002, "%s, line %d (nearby '%s'): %s", conf->err_file_name, conf->err_lino, conf->err_token, conf->err_msg);
       else
 	cli_msg(8002, "%s: %m", name);
       config_free(conf);