Improve error messages from configuration parser.

babeld.c

@@ -260,11 +260,13 @@ main(int argc, char **argv)
             config_file = "/etc/babeld.conf";
     }
     if(config_file) {
-        rc = parse_config_from_file(config_file);
+        int line;
+        rc = parse_config_from_file(config_file, &line);
         if(rc < 0) {
             fprintf(stderr,
-                    "Couldn't parse configuration from file %s.\n",
-                    config_file);
+                    "Couldn't parse configuration from file %s "
+                    "(error at line %d).\n",
+                    config_file, line);
             exit(1);
         }
     } else {

configuration.c

@@ -594,17 +594,37 @@ parse_config(gnc_t gnc, void *closure)
     return 1;
 }
 
+struct file_state {
+    FILE *f;
+    int line;
+};
+
+static int
+gnc_file(struct file_state *s)
+{
+    int c;
+    c = fgetc(s->f);
+    if(c == '\n')
+       s->line++;
+    return c;
+}
+
 int
-parse_config_from_file(char *filename)
+parse_config_from_file(const char *filename, int *line_return)
 {
-    FILE *f;
+    struct file_state s = { NULL, 1 };
     int rc;
 
-    f = fopen(filename, "r");
-    if(f == NULL)
+    s.f = fopen(filename, "r");
+    if(s.f == NULL) {
+        *line_return = 0;
         return -1;
-    rc = parse_config((gnc_t)fgetc, f);
-    fclose(f);
+    }
+
+    rc = parse_config((gnc_t)gnc_file, &s);
+    fclose(s.f);
+
+    *line_return = s.line;
     return rc;
 }
 

configuration.h

@@ -34,7 +34,7 @@ struct filter {
     struct filter *next;
 };
 
-int parse_config_from_file(char *filename);
+int parse_config_from_file(const char *filename, int *line_return);
 int parse_config_from_string(char *string);
 void renumber_filters(void);