Add support for %include funcionality on torrc #1922

config_get_lines is now split into two functions:
 - config_get_lines which is the same as before we had %include
 - config_get_lines_include which actually processes %include

13 files changed, 908 insertions, 24 deletions

diff --git a/changes/feature1922 b/changes/feature1922
new file mode 100644
index 0000000000..e3c059d4a5
--- /dev/null
+++ b/changes/feature1922
@@ -0,0 +1,11 @@
+  o Minor feature (include on config files):
+    - Allow the use of %include on configuration files to include settings
+      from other files or directories. Using %include with a directory will
+      include all (non-dot) files in that directory in lexically sorted order
+      (non-recursive), closes ticket 1922.
+    - Makes SAVECONF command return error when overwriting a torrc
+      that has includes. Using SAVECONF with the FORCE option will
+      allow it to overwrite torrc even if includes are used, closes ticket
+      1922.
+    - Adds config-can-saveconf to GETINFO command to tell if SAVECONF
+      will work without the FORCE option, closes ticket 1922.
diff --git a/doc/tor.1.txt b/doc/tor.1.txt
index 0af4e5f161..5e0a71ca26 100644
--- a/doc/tor.1.txt
+++ b/doc/tor.1.txt
@@ -153,6 +153,13 @@ values. To split one configuration entry into multiple lines, use a single
 backslash character (\) before the end of the line.  Comments can be used in
 such multiline entries, but they must start at the beginning of a line.
 
+Configuration options can be imported from files or folders using the %include
+option with the value being a path. If the path is a file, the options from the
+file will be parsed as if they were written where the %include option is. If
+the path is a folder, all files on that folder will be parsed following lexical
+order. Files starting with a dot are ignored. Files on subfolders are ignored.
+The %include option can be used recursively.
+
 By default, an option on the command line overrides an option found in the
 configuration file, and an option in a configuration file overrides one in
 the defaults file.
diff --git a/src/common/confline.c b/src/common/confline.c
index d4468f80ea..e078b1da04 100644
--- a/src/common/confline.c
+++ b/src/common/confline.c
@@ -8,6 +8,19 @@
 #include "confline.h"
 #include "torlog.h"
 #include "util.h"
+#include "container.h"
+
+static int config_get_lines_aux(const char *string, config_line_t **result,
+                                int extended, int allow_include,
+                                int *has_include, int recursion_level,
+                                config_line_t **last);
+static smartlist_t *config_get_file_list(const char *path);
+static int config_get_included_list(const char *path, int recursion_level,
+                                    int extended, config_line_t **list,
+                                    config_line_t **list_last);
+static int config_process_include(const char *path, int recursion_level,
+                                  int extended, config_line_t ***next,
+                                  config_line_t **list_last);
 
 /** Helper: allocate a new configuration option mapping 'key' to 'val',
  * append it to *<b>lst</b>. */
@@ -65,19 +78,25 @@ config_line_find(const config_line_t *lines,
   return NULL;
 }
 
-/** Helper: parse the config string and strdup into key/value
- * strings. Set *result to the list, or NULL if parsing the string
- * failed.  Return 0 on success, -1 on failure. Warn and ignore any
- * misformatted lines.
- *
- * If <b>extended</b> is set, then treat keys beginning with / and with + as
- * indicating "clear" and "append" respectively. */
-int
-config_get_lines(const char *string, config_line_t **result, int extended)
+/** Auxiliary function that does all the work of config_get_lines.
+ * <b>recursion_level</b> is the count of how many nested %includes we have.
+ * Returns the a pointer to the last element of the <b>result</b> in
+ * <b>last</b>. */
+static int
+config_get_lines_aux(const char *string, config_line_t **result, int extended,
+                     int allow_include, int *has_include, int recursion_level,
+                     config_line_t **last)
 {
-  config_line_t *list = NULL, **next;
+  config_line_t *list = NULL, **next, *list_last = NULL;
   char *k, *v;
   const char *parse_err;
+  int include_used = 0;
+
+  if (recursion_level > MAX_INCLUDE_RECURSION_LEVEL) {
+    log_warn(LD_CONFIG, "Error while parsing configuration: more than %d "
+             "nested %%includes.", MAX_INCLUDE_RECURSION_LEVEL);
+    return -1;
+  }
 
   next = &list;
   do {
@@ -108,25 +127,179 @@ config_get_lines(const char *string, config_line_t **result, int extended)
           command = CONFIG_LINE_CLEAR;
         }
       }
-      /* This list can get long, so we keep a pointer to the end of it
-       * rather than using config_line_append over and over and getting
-       * n^2 performance. */
-      *next = tor_malloc_zero(sizeof(config_line_t));
-      (*next)->key = k;
-      (*next)->value = v;
-      (*next)->next = NULL;
-      (*next)->command = command;
-      next = &((*next)->next);
+
+      if (allow_include && !strcmp(k, "%include")) {
+        tor_free(k);
+        include_used = 1;
+
+        if (config_process_include(v, recursion_level, extended, &next,
+                                   &list_last) < 0) {
+          log_warn(LD_CONFIG, "Error reading included configuration "
+                   "file or directory: \"%s\".", v);
+          config_free_lines(list);
+          tor_free(v);
+          return -1;
+        }
+        tor_free(v);
+      } else {
+        /* This list can get long, so we keep a pointer to the end of it
+         * rather than using config_line_append over and over and getting
+         * n^2 performance. */
+        *next = tor_malloc_zero(sizeof(**next));
+        (*next)->key = k;
+        (*next)->value = v;
+        (*next)->next = NULL;
+        (*next)->command = command;
+        list_last = *next;
+        next = &((*next)->next);
+      }
     } else {
       tor_free(k);
       tor_free(v);
     }
   } while (*string);
 
+  if (last) {
+    *last = list_last;
+  }
+  if (has_include) {
+    *has_include = include_used;
+  }
   *result = list;
   return 0;
 }
 
+/** Helper: parse the config string and strdup into key/value
+ * strings. Set *result to the list, or NULL if parsing the string
+ * failed. Set *has_include to 1 if <b>result</b> has values from
+ * %included files.  Return 0 on success, -1 on failure. Warn and ignore any
+ * misformatted lines.
+ *
+ * If <b>extended</b> is set, then treat keys beginning with / and with + as
+ * indicating "clear" and "append" respectively. */
+int
+config_get_lines_include(const char *string, config_line_t **result,
+                         int extended, int *has_include)
+{
+  return config_get_lines_aux(string, result, extended, 1, has_include, 1,
+                              NULL);
+}
+
+/** Same as config_get_lines_include but does not allow %include */
+int
+config_get_lines(const char *string, config_line_t **result, int extended)
+{
+  return config_get_lines_aux(string, result, extended, 0, NULL, 1, NULL);
+}
+
+/** Adds a list of configuration files present on <b>path</b> to
+ * <b>file_list</b>. <b>path</b> can be a file or a directory. If it is a file,
+ * only that file will be added to <b>file_list</b>. If it is a directory,
+ * all paths for files on that directory root (no recursion) except for files
+ * whose name starts with a dot will be added to <b>file_list</b>.
+ * Return 0 on success, -1 on failure. Ignores empty files.
+ */
+static smartlist_t *
+config_get_file_list(const char *path)
+{
+  smartlist_t *file_list = smartlist_new();
+  file_status_t file_type = file_status(path);
+  if (file_type == FN_FILE) {
+    smartlist_add_strdup(file_list, path);
+    return file_list;
+  } else if (file_type == FN_DIR) {
+    smartlist_t *all_files = tor_listdir(path);
+    if (!all_files) {
+      smartlist_free(file_list);
+      return NULL;
+    }
+    smartlist_sort_strings(all_files);
+    SMARTLIST_FOREACH_BEGIN(all_files, char *, f) {
+      if (f[0] == '.') {
+        tor_free(f);
+        continue;
+      }
+
+      char *fullname;
+      tor_asprintf(&fullname, "%s"PATH_SEPARATOR"%s", path, f);
+      tor_free(f);
+
+      if (file_status(fullname) != FN_FILE) {
+        tor_free(fullname);
+        continue;
+      }
+      smartlist_add(file_list, fullname);
+    } SMARTLIST_FOREACH_END(f);
+    smartlist_free(all_files);
+    return file_list;
+  } else if (file_type == FN_EMPTY) {
+      return file_list;
+  } else {
+    smartlist_free(file_list);
+    return NULL;
+  }
+}
+
+/** Creates a list of config lines present on included <b>path</b>.
+ * Set <b>list</b> to the list and <b>list_last</b> to the last element of
+ * <b>list</b>. Return 0 on success, -1 on failure. */
+static int
+config_get_included_list(const char *path, int recursion_level, int extended,
+                         config_line_t **list, config_line_t **list_last)
+{
+  char *included_conf = read_file_to_str(path, 0, NULL);
+  if (!included_conf) {
+    return -1;
+  }
+
+  if (config_get_lines_aux(included_conf, list, extended, 1, NULL,
+                           recursion_level+1, list_last) < 0) {
+    tor_free(included_conf);
+    return -1;
+  }
+
+  tor_free(included_conf);
+  return 0;
+}
+
+/** Process an %include <b>path</b> in a config file. Set <b>next</b> to a
+ * pointer to the next pointer of the last element of the config_line_t list
+ * obtained from the config file and <b>list_last</b> to the last element of
+ * the same list. Return 0 on success, -1 on failure. */
+static int
+config_process_include(const char *path, int recursion_level, int extended,
+                       config_line_t ***next, config_line_t **list_last)
+{
+  char *unquoted_path = get_unquoted_path(path);
+  if (!unquoted_path) {
+    return -1;
+  }
+
+  smartlist_t *config_files = config_get_file_list(unquoted_path);
+  if (!config_files) {
+    tor_free(unquoted_path);
+    return -1;
+  }
+  tor_free(unquoted_path);
+
+  SMARTLIST_FOREACH_BEGIN(config_files, char *, config_file) {
+    config_line_t *included_list = NULL;
+    if (config_get_included_list(config_file, recursion_level, extended,
+                                  &included_list, list_last) < 0) {
+      SMARTLIST_FOREACH(config_files, char *, f, tor_free(f));
+      smartlist_free(config_files);
+      return -1;
+    }
+    tor_free(config_file);
+
+    **next = included_list;
+    *next = &(*list_last)->next;
+
+  } SMARTLIST_FOREACH_END(config_file);
+  smartlist_free(config_files);
+  return 0;
+}
+
 /**
  * Free all the configuration lines on the linked list <b>front</b>.
  */
diff --git a/src/common/confline.h b/src/common/confline.h
index 477c6929a2..eb863e8fd8 100644
--- a/src/common/confline.h
+++ b/src/common/confline.h
@@ -15,6 +15,8 @@
 /* Removes all previous configuration for an option. */
 #define CONFIG_LINE_CLEAR 2
 
+#define MAX_INCLUDE_RECURSION_LEVEL 31
+
 /** A linked list of lines in a config file, or elsewhere */
 typedef struct config_line_t {
   char *key;
@@ -41,6 +43,8 @@ const config_line_t *config_line_find(const config_line_t *lines,
 int config_lines_eq(config_line_t *a, config_line_t *b);
 int config_count_key(const config_line_t *a, const char *key);
 int config_get_lines(const char *string, config_line_t **result, int extended);
+int config_get_lines_include(const char *string, config_line_t **result,
+                             int extended, int *has_include);
 void config_free_lines(config_line_t *front);
 const char *parse_config_line_from_str_verbose(const char *line,
                                        char **key_out, char **value_out,
diff --git a/src/common/util.c b/src/common/util.c
index ca2a0c4a9c..5c455585e7 100644
--- a/src/common/util.c
+++ b/src/common/util.c
@@ -3045,6 +3045,41 @@ unescape_string(const char *s, char **result, size_t *size_out)
   }
 }
 
+/** Removes enclosing quotes from <b>path</b> and unescapes quotes between the
+ * enclosing quotes. Backslashes are not unescaped. Return the unquoted
+ * <b>path</b> on sucess or 0 if <b>path</b> is not quoted correctly. */
+char *
+get_unquoted_path(const char *path)
+{
+  int len = strlen(path);
+
+  if (len == 0) {
+    return tor_strdup("");
+  }
+
+  int has_start_quote = (path[0] == '\"');
+  int has_end_quote = (len > 0 && path[len-1] == '\"');
+  if (has_start_quote != has_end_quote || (len == 1 && has_start_quote)) {
+    return NULL;
+  }
+
+  char *unquoted_path = tor_malloc(len - has_start_quote - has_end_quote + 1);
+  char *s = unquoted_path;
+  int i;
+  for (i = has_start_quote; i < len - has_end_quote; i++) {
+    if (path[i] == '\"' && (i > 0 && path[i-1] == '\\')) {
+      *(s-1) = path[i];
+    } else if (path[i] != '\"') {
+      *s++ = path[i];
+    } else {  /* unescaped quote */
+      tor_free(unquoted_path);
+      return NULL;
+    }
+  }
+  *s = '\0';
+  return unquoted_path;
+}
+
 /** Expand any homedir prefix on <b>filename</b>; return a newly allocated
  * string. */
 char *
diff --git a/src/common/util.h b/src/common/util.h
index 18eb57f1bc..d56abcee2e 100644
--- a/src/common/util.h
+++ b/src/common/util.h
@@ -389,6 +389,7 @@ char *read_file_to_str_until_eof(int fd, size_t max_bytes_to_read,
                                  size_t *sz_out)
   ATTR_MALLOC;
 const char *unescape_string(const char *s, char **result, size_t *size_out);
+char *get_unquoted_path(const char *path);
 char *expand_filename(const char *filename);
 MOCK_DECL(struct smartlist_t *, tor_listdir, (const char *dirname));
 int path_is_relative(const char *filename);
diff --git a/src/config/torrc.sample.in b/src/config/torrc.sample.in
index 37777443ac..8f3597f3f6 100644
--- a/src/config/torrc.sample.in
+++ b/src/config/torrc.sample.in
@@ -209,3 +209,12 @@
 ## address manually to your friends, uncomment this line:
 #PublishServerDescriptor 0
 
+## Configuration options can be imported from files or folders using the %include
+## option with the value being a path. If the path is a file, the options from the
+## file will be parsed as if they were written where the %include option is. If
+## the path is a folder, all files on that folder will be parsed following lexical
+## order. Files starting with a dot are ignored. Files on subfolders are ignored.
+## The %include option can be used recursively.
+#%include /etc/torrc.d/
+#%include /etc/torrc.custom
+
diff --git a/src/or/config.c b/src/or/config.c
index 09d558e1b4..a1212cfd3c 100644
--- a/src/or/config.c
+++ b/src/or/config.c
@@ -5056,6 +5056,7 @@ options_init_from_string(const char *cf_defaults, const char *cf,
   config_line_t *cl;
   int retval;
   setopt_err_t err = SETOPT_ERR_MISC;
+  int cf_has_include;
   tor_assert(msg);
 
   oldoptions = global_options; /* get_options unfortunately asserts if
@@ -5072,7 +5073,8 @@ options_init_from_string(const char *cf_defaults, const char *cf,
     if (!body)
       continue;
     /* get config lines, assign them */
-    retval = config_get_lines(body, &cl, 1);
+    retval = config_get_lines_include(body, &cl, 1,
+                                      body == cf ? &cf_has_include : NULL);
     if (retval < 0) {
       err = SETOPT_ERR_PARSE;
       goto err;
@@ -5100,6 +5102,8 @@ options_init_from_string(const char *cf_defaults, const char *cf,
     goto err;
   }
 
+  newoptions->IncludeUsed = cf_has_include;
+
   /* If this is a testing network configuration, change defaults
    * for a list of dependent config options, re-initialize newoptions
    * with the new defaults, and assign all options to it second time. */
@@ -5143,7 +5147,8 @@ options_init_from_string(const char *cf_defaults, const char *cf,
       if (!body)
         continue;
       /* get config lines, assign them */
-      retval = config_get_lines(body, &cl, 1);
+      retval = config_get_lines_include(body, &cl, 1,
+                                        body == cf ? &cf_has_include : NULL);
       if (retval < 0) {
         err = SETOPT_ERR_PARSE;
         goto err;
@@ -5166,6 +5171,8 @@ options_init_from_string(const char *cf_defaults, const char *cf,
     }
   }
 
+  newoptions->IncludeUsed = cf_has_include;
+
   /* Validate newoptions */
   if (options_validate(oldoptions, newoptions, newdefaultoptions,
                        0, msg) < 0) {
diff --git a/src/or/confparse.h b/src/or/confparse.h
index 6f5c681ba8..9c4205d07c 100644
--- a/src/or/confparse.h
+++ b/src/or/confparse.h
@@ -124,7 +124,6 @@ const char *config_find_deprecation(const config_format_t *fmt,
                                      const char *key);
 const config_var_t *config_find_option(const config_format_t *fmt,
                                        const char *key);
-
 const char *config_expand_abbrev(const config_format_t *fmt,
                                  const char *option,
                                  int command_line, int warn_obsolete);
diff --git a/src/or/control.c b/src/or/control.c
index 4e85c38123..083768c3d3 100644
--- a/src/or/control.c
+++ b/src/or/control.c
@@ -1462,8 +1462,10 @@ handle_control_saveconf(control_connection_t *conn, uint32_t len,
                         const char *body)
 {
   (void) len;
-  (void) body;
-  if (options_save_current()<0) {
+
+  int force = !strcmpstart(body, "FORCE");
+  const or_options_t *options = get_options();
+  if ((!force && options->IncludeUsed) || options_save_current() < 0) {
     connection_write_str_to_buf(
       "551 Unable to write configuration to disk.\r\n", conn);
   } else {
@@ -1677,6 +1679,8 @@ getinfo_helper_misc(control_connection_t *conn, const char *question,
       *answer = tor_strdup(a);
   } else if (!strcmp(question, "config-text")) {
     *answer = options_dump(get_options(), OPTIONS_DUMP_MINIMAL);
+  } else if (!strcmp(question, "config-can-saveconf")) {
+    *answer = tor_strdup(get_options()->IncludeUsed ? "0" : "1");
   } else if (!strcmp(question, "info/names")) {
     *answer = list_getinfo_options();
   } else if (!strcmp(question, "dormant")) {
@@ -2931,6 +2935,8 @@ static const getinfo_item_t getinfo_items[] = {
   ITEM("config-defaults-file", misc, "Current location of the defaults file."),
   ITEM("config-text", misc,
        "Return the string that would be written by a saveconf command."),
+  ITEM("config-can-saveconf", misc,
+       "Is it possible to save the configuration to the \"torrc\" file?"),
   ITEM("accounting/bytes", accounting,
        "Number of bytes read/written so far in the accounting interval."),
   ITEM("accounting/bytes-left", accounting,
diff --git a/src/or/or.h b/src/or/or.h
index 297ec47fc1..41d9e8445f 100644
--- a/src/or/or.h
+++ b/src/or/or.h
@@ -4549,6 +4549,9 @@ typedef struct {
    * do we enforce Ed25519 identity match? */
   /* NOTE: remove this option someday. */
   int AuthDirTestEd25519LinkKeys;
+
+  /** Bool (default: 0): Tells if a %include was used on torrc */
+  int IncludeUsed;
 } or_options_t;
 
 /** Persistent state for an onion router, as saved to disk. */
diff --git a/src/test/test_config.c b/src/test/test_config.c
index 98bcbadf7f..983fe88524 100644
--- a/src/test/test_config.c
+++ b/src/test/test_config.c
@@ -4810,6 +4810,542 @@ test_config_parse_log_severity(void *data)
   tor_free(severity);
 }
 
+static void
+test_config_include_limit(void *data)
+{
+  (void)data;
+
+  char *dir = tor_strdup(get_fname("test_include_limit"));
+  tt_ptr_op(dir, OP_NE, NULL);
+
+#ifdef _WIN32
+  tt_int_op(mkdir(dir), OP_EQ, 0);
+#else
+  tt_int_op(mkdir(dir, 0700), OP_EQ, 0);
+#endif
+
+  char torrc_path[PATH_MAX+1];
+  tor_snprintf(torrc_path, sizeof(torrc_path), "%s"PATH_SEPARATOR"torrc", dir);
+  char torrc_contents[1000];
+  tor_snprintf(torrc_contents, sizeof(torrc_contents), "%%include %s",
+               torrc_path);
+  tt_int_op(write_str_to_file(torrc_path, torrc_contents, 0), OP_EQ, 0);
+
+  config_line_t *result = NULL;
+  tt_int_op(config_get_lines_include(torrc_contents, &result, 0, NULL),
+            OP_EQ, -1);
+
+ done:
+  config_free_lines(result);
+  tor_free(dir);
+}
+
+static void
+test_config_include_does_not_exist(void *data)
+{
+  (void)data;
+
+  char *dir = tor_strdup(get_fname("test_include_does_not_exist"));
+  tt_ptr_op(dir, OP_NE, NULL);
+
+#ifdef _WIN32
+  tt_int_op(mkdir(dir), OP_EQ, 0);
+#else
+  tt_int_op(mkdir(dir, 0700), OP_EQ, 0);
+#endif
+
+  char missing_path[PATH_MAX+1];
+  tor_snprintf(missing_path, sizeof(missing_path), "%s"PATH_SEPARATOR"missing",
+               dir);
+  char torrc_contents[1000];
+  tor_snprintf(torrc_contents, sizeof(torrc_contents), "%%include %s",
+               missing_path);
+
+  config_line_t *result = NULL;
+  tt_int_op(config_get_lines_include(torrc_contents, &result, 0, NULL),
+            OP_EQ, -1);
+
+ done:
+  config_free_lines(result);
+  tor_free(dir);
+}
+
+static void
+test_config_include_error_in_included_file(void *data)
+{
+  (void)data;
+
+  char *dir = tor_strdup(get_fname("test_error_in_included_file"));
+  tt_ptr_op(dir, OP_NE, NULL);
+
+#ifdef _WIN32
+  tt_int_op(mkdir(dir), OP_EQ, 0);
+#else
+  tt_int_op(mkdir(dir, 0700), OP_EQ, 0);
+#endif
+
+  char invalid_path[PATH_MAX+1];
+  tor_snprintf(invalid_path, sizeof(invalid_path), "%s"PATH_SEPARATOR"invalid",
+               dir);
+  tt_int_op(write_str_to_file(invalid_path, "unclosed \"", 0), OP_EQ, 0);
+
+  char torrc_contents[1000];
+  tor_snprintf(torrc_contents, sizeof(torrc_contents), "%%include %s",
+               invalid_path);
+
+  config_line_t *result = NULL;
+  tt_int_op(config_get_lines_include(torrc_contents, &result, 0, NULL),
+            OP_EQ, -1);
+
+ done:
+  config_free_lines(result);
+  tor_free(dir);
+}
+
+static void
+test_config_include_empty_file_folder(void *data)
+{
+  (void)data;
+
+  char *dir = tor_strdup(get_fname("test_include_empty_file_folder"));
+  tt_ptr_op(dir, OP_NE, NULL);
+
+#ifdef _WIN32
+  tt_int_op(mkdir(dir), OP_EQ, 0);
+#else
+  tt_int_op(mkdir(dir, 0700), OP_EQ, 0);
+#endif
+
+  char folder_path[PATH_MAX+1];
+  tor_snprintf(folder_path, sizeof(folder_path), "%s"PATH_SEPARATOR"empty_dir",
+               dir);
+#ifdef _WIN32
+  tt_int_op(mkdir(folder_path), OP_EQ, 0);
+#else
+  tt_int_op(mkdir(folder_path, 0700), OP_EQ, 0);
+#endif
+  char file_path[PATH_MAX+1];
+  tor_snprintf(file_path, sizeof(file_path), "%s"PATH_SEPARATOR"empty_file",
+               dir);
+  tt_int_op(write_str_to_file(file_path, "", 0), OP_EQ, 0);
+
+  char torrc_contents[1000];
+  tor_snprintf(torrc_contents, sizeof(torrc_contents),
+               "%%include %s\n"
+               "%%include %s\n",
+               folder_path, file_path);
+
+  config_line_t *result = NULL;
+  int include_used;
+  tt_int_op(config_get_lines_include(torrc_contents, &result, 0,&include_used),
+            OP_EQ, 0);
+  tt_ptr_op(result, OP_EQ, NULL);
+  tt_int_op(include_used, OP_EQ, 1);
+
+ done:
+  config_free_lines(result);
+  tor_free(dir);
+}
+
+static void
+test_config_include_recursion_before_after(void *data)
+{
+  (void)data;
+
+  char *dir = tor_strdup(get_fname("test_include_recursion_before_after"));
+  tt_ptr_op(dir, OP_NE, NULL);
+
+#ifdef _WIN32
+  tt_int_op(mkdir(dir), OP_EQ, 0);
+#else
+  tt_int_op(mkdir(dir, 0700), OP_EQ, 0);
+#endif
+
+  char torrc_path[PATH_MAX+1];
+  tor_snprintf(torrc_path, sizeof(torrc_path), "%s"PATH_SEPARATOR"torrc", dir);
+
+  char file_contents[1000];
+  const int limit = MAX_INCLUDE_RECURSION_LEVEL;
+  int i;
+  // Loop backwards so file_contents has the contents of the first file by the
+  // end of the loop
+  for (i = limit; i > 0; i--) {
+    if (i < limit) {
+      tor_snprintf(file_contents, sizeof(file_contents),
+                   "Test %d\n"
+                   "%%include %s%d\n"
+                   "Test %d\n",
+                   i, torrc_path, i + 1, 2 * limit - i);
+    } else {
+      tor_snprintf(file_contents, sizeof(file_contents), "Test %d\n", i);
+    }
+
+    if (i > 1) {
+      char file_path[PATH_MAX+1];
+      tor_snprintf(file_path, sizeof(file_path), "%s%d", torrc_path, i);
+      tt_int_op(write_str_to_file(file_path, file_contents, 0), OP_EQ, 0);
+    }
+  }
+
+  config_line_t *result = NULL;
+  int include_used;
+  tt_int_op(config_get_lines_include(file_contents, &result, 0, &include_used),
+            OP_EQ, 0);
+  tt_ptr_op(result, OP_NE, NULL);
+  tt_int_op(include_used, OP_EQ, 1);
+
+  int len = 0;
+  config_line_t *next;
+  for (next = result; next != NULL; next = next->next) {
+    char expected[10];
+    tor_snprintf(expected, sizeof(expected), "%d", len + 1);
+    tt_str_op(next->key, OP_EQ, "Test");
+    tt_str_op(next->value, OP_EQ, expected);
+    len++;
+  }
+  tt_int_op(len, OP_EQ, 2 * limit - 1);
+
+ done:
+  config_free_lines(result);
+  tor_free(dir);
+}
+
+static void
+test_config_include_recursion_after_only(void *data)
+{
+  (void)data;
+
+  char *dir = tor_strdup(get_fname("test_include_recursion_after_only"));
+  tt_ptr_op(dir, OP_NE, NULL);
+
+#ifdef _WIN32
+  tt_int_op(mkdir(dir), OP_EQ, 0);
+#else
+  tt_int_op(mkdir(dir, 0700), OP_EQ, 0);
+#endif
+
+  char torrc_path[PATH_MAX+1];
+  tor_snprintf(torrc_path, sizeof(torrc_path), "%s"PATH_SEPARATOR"torrc", dir);
+
+  char file_contents[1000];
+  const int limit = MAX_INCLUDE_RECURSION_LEVEL;
+  int i;
+  // Loop backwards so file_contents has the contents of the first file by the
+  // end of the loop
+  for (i = limit; i > 0; i--) {
+    int n = (i - limit - 1) * -1;
+    if (i < limit) {
+      tor_snprintf(file_contents, sizeof(file_contents),
+                   "%%include %s%d\n"
+                   "Test %d\n",
+                   torrc_path, i + 1, n);
+    } else {
+      tor_snprintf(file_contents, sizeof(file_contents), "Test %d\n", n);
+    }
+
+    if (i > 1) {
+      char file_path[PATH_MAX+1];
+      tor_snprintf(file_path, sizeof(file_path), "%s%d", torrc_path, i);
+      tt_int_op(write_str_to_file(file_path, file_contents, 0), OP_EQ, 0);
+    }
+  }
+
+  config_line_t *result = NULL;
+  int include_used;
+  tt_int_op(config_get_lines_include(file_contents, &result, 0, &include_used),
+            OP_EQ, 0);
+  tt_ptr_op(result, OP_NE, NULL);
+  tt_int_op(include_used, OP_EQ, 1);
+
+  int len = 0;
+  config_line_t *next;
+  for (next = result; next != NULL; next = next->next) {
+    char expected[10];
+    tor_snprintf(expected, sizeof(expected), "%d", len + 1);
+    tt_str_op(next->key, OP_EQ, "Test");
+    tt_str_op(next->value, OP_EQ, expected);
+    len++;
+  }
+  tt_int_op(len, OP_EQ, limit);
+
+ done:
+  config_free_lines(result);
+  tor_free(dir);
+}
+
+static void
+test_config_include_folder_order(void *data)
+{
+  (void)data;
+
+  char *dir = tor_strdup(get_fname("test_include_folder_order"));
+  tt_ptr_op(dir, OP_NE, NULL);
+
+#ifdef _WIN32
+  tt_int_op(mkdir(dir), OP_EQ, 0);
+#else
+  tt_int_op(mkdir(dir, 0700), OP_EQ, 0);
+#endif
+
+  char torrcd[PATH_MAX+1];
+  tor_snprintf(torrcd, sizeof(torrcd), "%s"PATH_SEPARATOR"%s", dir, "torrc.d");
+
+#ifdef _WIN32
+  tt_int_op(mkdir(torrcd), OP_EQ, 0);
+#else
+  tt_int_op(mkdir(torrcd, 0700), OP_EQ, 0);
+#endif
+
+  // test that files in subfolders are ignored
+  char path[PATH_MAX+1];
+  tor_snprintf(path, sizeof(path), "%s"PATH_SEPARATOR"%s", torrcd,
+               "subfolder");
+
+#ifdef _WIN32
+  tt_int_op(mkdir(path), OP_EQ, 0);
+#else
+  tt_int_op(mkdir(path, 0700), OP_EQ, 0);
+#endif
+
+  char path2[PATH_MAX+1];
+  tor_snprintf(path2, sizeof(path2), "%s"PATH_SEPARATOR"%s", path,
+               "01_ignore");
+  tt_int_op(write_str_to_file(path2, "ShouldNotSee 1\n", 0), OP_EQ, 0);
+
+  // test that files starting with . are ignored
+  tor_snprintf(path, sizeof(path), "%s"PATH_SEPARATOR"%s", torrcd, ".dot");
+  tt_int_op(write_str_to_file(path, "ShouldNotSee 2\n", 0), OP_EQ, 0);
+
+  // test file order
+  tor_snprintf(path, sizeof(path), "%s"PATH_SEPARATOR"%s", torrcd, "01_1st");
+  tt_int_op(write_str_to_file(path, "Test 1\n", 0), OP_EQ, 0);
+
+  tor_snprintf(path, sizeof(path), "%s"PATH_SEPARATOR"%s", torrcd, "02_2nd");
+  tt_int_op(write_str_to_file(path, "Test 2\n", 0), OP_EQ, 0);
+
+  tor_snprintf(path, sizeof(path), "%s"PATH_SEPARATOR"%s", torrcd, "aa_3rd");
+  tt_int_op(write_str_to_file(path, "Test 3\n", 0), OP_EQ, 0);
+
+  tor_snprintf(path, sizeof(path), "%s"PATH_SEPARATOR"%s", torrcd, "ab_4th");
+  tt_int_op(write_str_to_file(path, "Test 4\n", 0), OP_EQ, 0);
+
+  char torrc_contents[1000];
+  tor_snprintf(torrc_contents, sizeof(torrc_contents),
+               "%%include %s\n",
+               torrcd);
+
+  config_line_t *result = NULL;
+  int include_used;
+  tt_int_op(config_get_lines_include(torrc_contents, &result, 0,&include_used),
+            OP_EQ, 0);
+  tt_ptr_op(result, OP_NE, NULL);
+  tt_int_op(include_used, OP_EQ, 1);
+
+  int len = 0;
+  config_line_t *next;
+  for (next = result; next != NULL; next = next->next) {
+    char expected[10];
+    tor_snprintf(expected, sizeof(expected), "%d", len + 1);
+    tt_str_op(next->key, OP_EQ, "Test");
+    tt_str_op(next->value, OP_EQ, expected);
+    len++;
+  }
+  tt_int_op(len, OP_EQ, 4);
+
+ done:
+  config_free_lines(result);
+  tor_free(dir);
+}
+
+static void
+test_config_include_path_syntax(void *data)
+{
+  (void)data;
+
+  char *dir = tor_strdup(get_fname("test_include_path_syntax"));
+  tt_ptr_op(dir, OP_NE, NULL);
+
+#ifdef _WIN32
+  tt_int_op(mkdir(dir), OP_EQ, 0);
+#else
+  tt_int_op(mkdir(dir, 0700), OP_EQ, 0);
+#endif
+
+  char torrc_contents[1000];
+  tor_snprintf(torrc_contents, sizeof(torrc_contents),
+               "%%include \"%s\"\n"
+               "%%include %s"PATH_SEPARATOR"\n"
+               "%%include \"%s"PATH_SEPARATOR"\"\n",
+               dir, dir, dir);
+
+  config_line_t *result = NULL;
+  int include_used;
+  tt_int_op(config_get_lines_include(torrc_contents, &result, 0,&include_used),
+            OP_EQ, 0);
+  tt_ptr_op(result, OP_EQ, NULL);
+  tt_int_op(include_used, OP_EQ, 1);
+
+ done:
+  config_free_lines(result);
+  tor_free(dir);
+}
+
+static void
+test_config_include_not_processed(void *data)
+{
+  (void)data;
+
+  char torrc_contents[1000] = "%include does_not_exist\n";
+  config_line_t *result = NULL;
+  tt_int_op(config_get_lines(torrc_contents, &result, 0),OP_EQ, 0);
+  tt_ptr_op(result, OP_NE, NULL);
+
+  int len = 0;
+  config_line_t *next;
+  for (next = result; next != NULL; next = next->next) {
+    tt_str_op(next->key, OP_EQ, "%include");
+    tt_str_op(next->value, OP_EQ, "does_not_exist");
+    len++;
+  }
+  tt_int_op(len, OP_EQ, 1);
+
+ done:
+  config_free_lines(result);
+}
+
+static void
+test_config_include_has_include(void *data)
+{
+  (void)data;
+
+  char *dir = tor_strdup(get_fname("test_include_has_include"));
+  tt_ptr_op(dir, OP_NE, NULL);
+
+#ifdef _WIN32
+  tt_int_op(mkdir(dir), OP_EQ, 0);
+#else
+  tt_int_op(mkdir(dir, 0700), OP_EQ, 0);
+#endif
+
+  char torrc_contents[1000] = "Test 1\n";
+  config_line_t *result = NULL;
+  int include_used;
+
+  tt_int_op(config_get_lines_include(torrc_contents, &result, 0,&include_used),
+            OP_EQ, 0);
+  tt_int_op(include_used, OP_EQ, 0);
+  config_free_lines(result);
+
+  tor_snprintf(torrc_contents, sizeof(torrc_contents), "%%include %s\n", dir);
+  tt_int_op(config_get_lines_include(torrc_contents, &result, 0,&include_used),
+            OP_EQ, 0);
+  tt_int_op(include_used, OP_EQ, 1);
+
+ done:
+  config_free_lines(result);
+  tor_free(dir);
+}
+
+static void
+test_config_include_flag_both_without(void *data)
+{
+  (void)data;
+
+  char *errmsg = NULL;
+  char conf_empty[1000];
+  tor_snprintf(conf_empty, sizeof(conf_empty),
+               "DataDirectory %s\n",
+               get_fname(NULL));
+  // test with defaults-torrc and torrc without include
+  int ret = options_init_from_string(conf_empty, conf_empty, CMD_RUN_UNITTESTS,
+                                     NULL, &errmsg);
+  tt_int_op(ret, OP_EQ, 0);
+
+  const or_options_t *options = get_options();
+  tt_int_op(options->IncludeUsed, OP_EQ, 0);
+
+ done:
+  tor_free(errmsg);
+}
+
+static void
+test_config_include_flag_torrc_only(void *data)
+{
+  (void)data;
+
+  char *errmsg = NULL;
+  char *dir = tor_strdup(get_fname("test_include_flag_torrc_only"));
+  tt_ptr_op(dir, OP_NE, NULL);
+
+#ifdef _WIN32
+  tt_int_op(mkdir(dir), OP_EQ, 0);
+#else
+  tt_int_op(mkdir(dir, 0700), OP_EQ, 0);
+#endif
+
+  char path[PATH_MAX+1];
+  tor_snprintf(path, sizeof(path), "%s"PATH_SEPARATOR"%s", dir, "dummy");
+  tt_int_op(write_str_to_file(path, "\n", 0), OP_EQ, 0);
+
+  char conf_empty[1000];
+  tor_snprintf(conf_empty, sizeof(conf_empty),
+               "DataDirectory %s\n",
+               get_fname(NULL));
+  char conf_include[1000];
+  tor_snprintf(conf_include, sizeof(conf_include), "%%include %s", path);
+
+  // test with defaults-torrc without include and torrc with include
+  int ret = options_init_from_string(conf_empty, conf_include,
+                                     CMD_RUN_UNITTESTS, NULL, &errmsg);
+  tt_int_op(ret, OP_EQ, 0);
+
+  const or_options_t *options = get_options();
+  tt_int_op(options->IncludeUsed, OP_EQ, 1);
+
+ done:
+  tor_free(errmsg);
+  tor_free(dir);
+}
+
+static void
+test_config_include_flag_defaults_only(void *data)
+{
+  (void)data;
+
+  char *errmsg = NULL;
+  char *dir = tor_strdup(get_fname("test_include_flag_defaults_only"));
+  tt_ptr_op(dir, OP_NE, NULL);
+
+#ifdef _WIN32
+  tt_int_op(mkdir(dir), OP_EQ, 0);
+#else
+  tt_int_op(mkdir(dir, 0700), OP_EQ, 0);
+#endif
+
+  char path[PATH_MAX+1];
+  tor_snprintf(path, sizeof(path), "%s"PATH_SEPARATOR"%s", dir, "dummy");
+  tt_int_op(write_str_to_file(path, "\n", 0), OP_EQ, 0);
+
+  char conf_empty[1000];
+  tor_snprintf(conf_empty, sizeof(conf_empty),
+               "DataDirectory %s\n",
+               get_fname(NULL));
+  char conf_include[1000];
+  tor_snprintf(conf_include, sizeof(conf_include), "%%include %s", path);
+
+  // test with defaults-torrc with include and torrc without include
+  int ret = options_init_from_string(conf_include, conf_empty,
+                                     CMD_RUN_UNITTESTS, NULL, &errmsg);
+  tt_int_op(ret, OP_EQ, 0);
+
+  const or_options_t *options = get_options();
+  tt_int_op(options->IncludeUsed, OP_EQ, 0);
+
+ done:
+  tor_free(errmsg);
+  tor_free(dir);
+}
+
 #define CONFIG_TEST(name, flags)                          \
   { #name, test_config_ ## name, flags, NULL, NULL }
 
@@ -4836,6 +5372,19 @@ struct testcase_t config_tests[] = {
   CONFIG_TEST(parse_port_config__ports__server_options, 0),
   CONFIG_TEST(parse_port_config__ports__ports_given, 0),
   CONFIG_TEST(parse_log_severity, 0),
+  CONFIG_TEST(include_limit, 0),
+  CONFIG_TEST(include_does_not_exist, 0),
+  CONFIG_TEST(include_error_in_included_file, 0),
+  CONFIG_TEST(include_empty_file_folder, 0),
+  CONFIG_TEST(include_recursion_before_after, 0),
+  CONFIG_TEST(include_recursion_after_only, 0),
+  CONFIG_TEST(include_folder_order, 0),
+  CONFIG_TEST(include_path_syntax, 0),
+  CONFIG_TEST(include_not_processed, 0),
+  CONFIG_TEST(include_has_include, 0),
+  CONFIG_TEST(include_flag_both_without, TT_FORK),
+  CONFIG_TEST(include_flag_torrc_only, TT_FORK),
+  CONFIG_TEST(include_flag_defaults_only, TT_FORK),
   END_OF_TESTCASES
 };
 
diff --git a/src/test/test_util.c b/src/test/test_util.c
index b3f8ecdf51..a861f15ab1 100644
--- a/src/test/test_util.c
+++ b/src/test/test_util.c
@@ -5731,6 +5731,85 @@ test_util_htonll(void *arg)
   ;
 }
 
+static void
+test_util_get_unquoted_path(void *arg)
+{
+  (void)arg;
+
+  char *r;
+
+  r = get_unquoted_path("\""); // "
+  tt_ptr_op(r, OP_EQ, NULL);
+  tor_free(r);
+
+  r = get_unquoted_path("\"\"\""); // """
+  tt_ptr_op(r, OP_EQ, NULL);
+  tor_free(r);
+
+  r = get_unquoted_path("\\\""); // \"
+  tt_ptr_op(r, OP_EQ, NULL);
+  tor_free(r);
+
+  r = get_unquoted_path("\\\"\\\""); // \"\"
+  tt_ptr_op(r, OP_EQ, NULL);
+  tor_free(r);
+
+  r = get_unquoted_path("A\\B\\C\""); // A\B\C"
+  tt_ptr_op(r, OP_EQ, NULL);
+  tor_free(r);
+
+  r = get_unquoted_path("\"A\\B\\C"); // "A\B\C
+  tt_ptr_op(r, OP_EQ, NULL);
+  tor_free(r);
+
+  r = get_unquoted_path("\"A\\B\"C\""); // "A\B"C"
+  tt_ptr_op(r, OP_EQ, NULL);
+  tor_free(r);
+
+  r = get_unquoted_path("A\\B\"C"); // A\B"C
+  tt_ptr_op(r, OP_EQ, NULL);
+  tor_free(r);
+
+  r = get_unquoted_path("");
+  tt_str_op(r, OP_EQ, "");
+  tor_free(r);
+
+  r = get_unquoted_path("\"\""); // ""
+  tt_str_op(r, OP_EQ, "");
+  tor_free(r);
+
+  r = get_unquoted_path("A\\B\\C"); // A\B\C
+  tt_str_op(r, OP_EQ, "A\\B\\C"); // A\B\C
+  tor_free(r);
+
+  r = get_unquoted_path("\"A\\B\\C\""); // "A\B\C"
+  tt_str_op(r, OP_EQ, "A\\B\\C"); // A\B\C
+  tor_free(r);
+
+  r = get_unquoted_path("\"\\\""); // "\"
+  tt_str_op(r, OP_EQ, "\\"); // \ /* comment to prevent line continuation */
+  tor_free(r);
+
+  r = get_unquoted_path("\"\\\"\""); // "\""
+  tt_str_op(r, OP_EQ, "\""); // "
+  tor_free(r);
+
+  r = get_unquoted_path("\"A\\B\\C\\\"\""); // "A\B\C\""
+  tt_str_op(r, OP_EQ, "A\\B\\C\""); // A\B\C"
+  tor_free(r);
+
+  r = get_unquoted_path("A\\B\\\"C"); // A\B\"C
+  tt_str_op(r, OP_EQ, "A\\B\"C"); // A\B"C
+  tor_free(r);
+
+  r = get_unquoted_path("\"A\\B\\\"C\""); // "A\B\"C"
+  tt_str_op(r, OP_EQ, "A\\B\"C"); // A\B"C
+  tor_free(r);
+
+ done:
+  ;
+}
+
 #define UTIL_LEGACY(name)                                               \
   { #name, test_util_ ## name , 0, NULL, NULL }
 
@@ -5833,6 +5912,7 @@ struct testcase_t util_tests[] = {
   UTIL_TEST(monotonic_time, 0),
   UTIL_TEST(monotonic_time_ratchet, TT_FORK),
   UTIL_TEST(htonll, 0),
+  UTIL_TEST(get_unquoted_path, 0),
   END_OF_TESTCASES
 };