Split the generic config_fmt_t code into a new confparse.c file

This helps us split up one of our larger files, and sets the stage
for refactoring the configuration backend a little

9 files changed, 1375 insertions, 1333 deletions

diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c
index 4384e291f..ae44de0e8 100644
--- a/src/or/circuitbuild.c
+++ b/src/or/circuitbuild.c
@@ -16,6 +16,7 @@
 #include "circuitlist.h"
 #include "circuituse.h"
 #include "config.h"
+#include "confparse.h"
 #include "connection.h"
 #include "connection_edge.h"
 #include "connection_or.h"
diff --git a/src/or/config.c b/src/or/config.c
index 8f79c44cc..ce495f325 100644
--- a/src/or/config.c
+++ b/src/or/config.c
@@ -19,6 +19,7 @@
 #include "connection_edge.h"
 #include "connection_or.h"
 #include "control.h"
+#include "confparse.h"
 #include "cpuworker.h"
 #include "dirserv.h"
 #include "dirvote.h"
@@ -45,48 +46,6 @@
 /* From main.c */
 extern int quiet_level;
 
-/** Enumeration of types which option values can take */
-typedef enum config_type_t {
-  CONFIG_TYPE_STRING = 0,   /**< An arbitrary string. */
-  CONFIG_TYPE_FILENAME,     /**< A filename: some prefixes get expanded. */
-  CONFIG_TYPE_UINT,         /**< A non-negative integer less than MAX_INT */
-  CONFIG_TYPE_INT,          /**< Any integer. */
-  CONFIG_TYPE_PORT,         /**< A port from 1...65535, 0 for "not set", or
-                             * "auto".  */
-  CONFIG_TYPE_INTERVAL,     /**< A number of seconds, with optional units*/
-  CONFIG_TYPE_MSEC_INTERVAL,/**< A number of milliseconds, with optional
-                              * units */
-  CONFIG_TYPE_MEMUNIT,      /**< A number of bytes, with optional units*/
-  CONFIG_TYPE_DOUBLE,       /**< A floating-point value */
-  CONFIG_TYPE_BOOL,         /**< A boolean value, expressed as 0 or 1. */
-  CONFIG_TYPE_AUTOBOOL,     /**< A boolean+auto value, expressed 0 for false,
-                             * 1 for true, and -1 for auto  */
-  CONFIG_TYPE_ISOTIME,      /**< An ISO-formatted time relative to GMT. */
-  CONFIG_TYPE_CSV,          /**< A list of strings, separated by commas and
-                              * optional whitespace. */
-  CONFIG_TYPE_LINELIST,     /**< Uninterpreted config lines */
-  CONFIG_TYPE_LINELIST_S,   /**< Uninterpreted, context-sensitive config lines,
-                             * mixed with other keywords. */
-  CONFIG_TYPE_LINELIST_V,   /**< Catch-all "virtual" option to summarize
-                             * context-sensitive config lines when fetching.
-                             */
-  CONFIG_TYPE_ROUTERSET,    /**< A list of router names, addrs, and fps,
-                             * parsed into a routerset_t. */
-  CONFIG_TYPE_OBSOLETE,     /**< Obsolete (ignored) option. */
-} config_type_t;
-
-/** An abbreviation for a configuration option allowed on the command line. */
-typedef struct config_abbrev_t {
-  const char *abbreviated;
-  const char *full;
-  int commandline_only;
-  int warn;
-} config_abbrev_t;
-
-/* Handy macro for declaring "In the config file or on the command line,
- * you can abbreviate <b>tok</b>s as <b>tok</b>". */
-#define PLURAL(tok) { #tok, #tok "s", 0, 0 }
-
 /** A list of abbreviations and aliases to map command-line options, obsolete
  * option names, or alternative option names, to their current values. */
 static config_abbrev_t _option_abbrevs[] = {
@@ -145,16 +104,6 @@ static config_abbrev_t _state_abbrevs[] = {
   { "EntryNodeUnlistedSince", "EntryGuardUnlistedSince", 0, 0 },
   { NULL, NULL, 0, 0},
 };
-#undef PLURAL
-
-/** A variable allowed in the configuration file or on the command line. */
-typedef struct config_var_t {
-  const char *name; /**< The full keyword (case insensitive). */
-  config_type_t type; /**< How to interpret the type and turn it into a
-                       * value. */
-  off_t var_offset; /**< Offset of the corresponding member of or_options_t. */
-  const char *initvalue; /**< String (or null) describing initial value. */
-} config_var_t;
 
 /** An entry for config_vars: "The option <b>name</b> has type
  * CONFIG_TYPE_<b>conftype</b>, and corresponds to
@@ -554,61 +503,9 @@ static config_var_t _state_vars[] = {
 #undef V
 #undef OBSOLETE
 
-/** Represents an English description of a configuration variable; used when
- * generating configuration file comments. */
-typedef struct config_var_description_t {
-  const char *name;
-  const char *description;
-} config_var_description_t;
-
-/** Type of a callback to validate whether a given configuration is
- * well-formed and consistent. See options_trial_assign() for documentation
- * of arguments. */
-typedef int (*validate_fn_t)(void*,void*,int,char**);
-
-/** Information on the keys, value types, key-to-struct-member mappings,
- * variable descriptions, validation functions, and abbreviations for a
- * configuration or storage format. */
-typedef struct {
-  size_t size; /**< Size of the struct that everything gets parsed into. */
-  uint32_t magic; /**< Required 'magic value' to make sure we have a struct
-                   * of the right type. */
-  off_t magic_offset; /**< Offset of the magic value within the struct. */
-  config_abbrev_t *abbrevs; /**< List of abbreviations that we expand when
-                             * parsing this format. */
-  config_var_t *vars; /**< List of variables we recognize, their default
-                       * values, and where we stick them in the structure. */
-  validate_fn_t validate_fn; /**< Function to validate config. */
-  /** If present, extra is a LINELIST variable for unrecognized
-   * lines.  Otherwise, unrecognized lines are an error. */
-  config_var_t *extra;
-} config_format_t;
-
-/** Macro: assert that <b>cfg</b> has the right magic field for format
- * <b>fmt</b>. */
-#define CHECK(fmt, cfg) STMT_BEGIN                                      \
-    tor_assert(fmt && cfg);                                             \
-    tor_assert((fmt)->magic ==                                          \
-               *(uint32_t*)STRUCT_VAR_P(cfg,fmt->magic_offset));        \
-  STMT_END
-
 #ifdef _WIN32
 static char *get_windows_conf_root(void);
 #endif
-static void config_line_append(config_line_t **lst,
-                               const char *key, const char *val);
-static void option_clear(const config_format_t *fmt, or_options_t *options,
-                         const config_var_t *var);
-static void option_reset(const config_format_t *fmt, or_options_t *options,
-                         const config_var_t *var, int use_defaults);
-static void config_free(const config_format_t *fmt, void *options);
-static int config_lines_eq(config_line_t *a, config_line_t *b);
-static int config_count_key(const config_line_t *a, const char *key);
-static int option_is_same(const config_format_t *fmt,
-                          const or_options_t *o1, const or_options_t *o2,
-                          const char *name);
-static or_options_t *options_dup(const config_format_t *fmt,
-                                 const or_options_t *old);
 static int options_validate(or_options_t *old_options,
                             or_options_t *options,
                             int from_setconf, char **msg);
@@ -639,18 +536,11 @@ static int check_server_ports(const smartlist_t *ports,
 static int validate_data_directory(or_options_t *options);
 static int write_configuration_file(const char *fname,
                                     const or_options_t *options);
-static config_line_t *get_assigned_option(const config_format_t *fmt,
-                                        const void *options, const char *key,
-                                        int escape_val);
-static void config_init(const config_format_t *fmt, void *options);
 static int or_state_validate(or_state_t *old_options, or_state_t *options,
                              int from_setconf, char **msg);
 static int or_state_load(void);
 static int options_init_logs(or_options_t *options, int validate_only);
 
-static uint64_t config_parse_memunit(const char *s, int *ok);
-static int config_parse_msec_interval(const char *s, int *ok);
-static int config_parse_interval(const char *s, int *ok);
 static void init_libevent(const or_options_t *options);
 static int opt_streq(const char *s1, const char *s2);
 
@@ -717,16 +607,6 @@ get_dirportfrontpage(void)
   return global_dirfrontpagecontents;
 }
 
-/** Allocate an empty configuration object of a given format type. */
-static void *
-config_new(const config_format_t *fmt)
-{
-  void *opts = tor_malloc_zero(fmt->size);
-  *(uint32_t*)STRUCT_VAR_P(opts, fmt->magic_offset) = fmt->magic;
-  CHECK(fmt, opts);
-  return opts;
-}
-
 /** Return the currently configured options. */
 or_options_t *
 get_options_mutable(void)
@@ -777,8 +657,9 @@ set_options(or_options_t *new_val, char **msg)
           var->type == CONFIG_TYPE_OBSOLETE) {
         continue;
       }
-      if (!option_is_same(&options_format, new_val, old_options, var_name)) {
-        line = get_assigned_option(&options_format, new_val, var_name, 1);
+      if (!config_is_same(&options_format, new_val, old_options, var_name)) {
+        line = config_get_assigned_option(&options_format, new_val,
+                                          var_name, 1);
 
         if (line) {
           for (; line; line = line->next) {
@@ -1848,42 +1729,6 @@ options_act(const or_options_t *old_options)
   return 0;
 }
 
-/*
- * Functions to parse config options
- */
-
-/** If <b>option</b> is an official abbreviation for a longer option,
- * return the longer option.  Otherwise return <b>option</b>.
- * If <b>command_line</b> is set, apply all abbreviations.  Otherwise, only
- * apply abbreviations that work for the config file and the command line.
- * If <b>warn_obsolete</b> is set, warn about deprecated names. */
-static const char *
-expand_abbrev(const config_format_t *fmt, const char *option, int command_line,
-              int warn_obsolete)
-{
-  int i;
-  if (! fmt->abbrevs)
-    return option;
-  for (i=0; fmt->abbrevs[i].abbreviated; ++i) {
-    /* Abbreviations are case insensitive. */
-    if (!strcasecmp(option,fmt->abbrevs[i].abbreviated) &&
-        (command_line || !fmt->abbrevs[i].commandline_only)) {
-      if (warn_obsolete && fmt->abbrevs[i].warn) {
-        log_warn(LD_CONFIG,
-                 "The configuration option '%s' is deprecated; "
-                 "use '%s' instead.",
-                 fmt->abbrevs[i].abbreviated,
-                 fmt->abbrevs[i].full);
-      }
-      /* Keep going through the list in case we want to rewrite it more.
-       * (We could imagine recursing here, but I don't want to get the
-       * user into an infinite loop if we craft our list wrong.) */
-      option = fmt->abbrevs[i].full;
-    }
-  }
-  return option;
-}
-
 /** Helper: Read a list of configuration options from the command line.
  * If successful, put them in *<b>result</b> and return 0, and return
  * -1 and leave *<b>result</b> alone. */
@@ -1943,7 +1788,7 @@ config_get_commandlines(int argc, char **argv, config_line_t **result)
       return -1;
     }
 
-    (*new)->key = tor_strdup(expand_abbrev(&options_format, s, 1, 1));
+    (*new)->key = tor_strdup(config_expand_abbrev(&options_format, s, 1, 1));
     (*new)->value = want_arg ? tor_strdup(argv[i+1]) : tor_strdup("");
     (*new)->command = command;
     (*new)->next = NULL;
@@ -1957,444 +1802,6 @@ config_get_commandlines(int argc, char **argv, config_line_t **result)
   return 0;
 }
 
-/** Helper: allocate a new configuration option mapping 'key' to 'val',
- * append it to *<b>lst</b>. */
-static void
-config_line_append(config_line_t **lst,
-                   const char *key,
-                   const char *val)
-{
-  config_line_t *newline;
-
-  newline = tor_malloc_zero(sizeof(config_line_t));
-  newline->key = tor_strdup(key);
-  newline->value = tor_strdup(val);
-  newline->next = NULL;
-  while (*lst)
-    lst = &((*lst)->next);
-
-  (*lst) = newline;
-}
-
-/** 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)
-{
-  config_line_t *list = NULL, **next;
-  char *k, *v;
-
-  next = &list;
-  do {
-    k = v = NULL;
-    string = parse_config_line_from_str(string, &k, &v);
-    if (!string) {
-      config_free_lines(list);
-      tor_free(k);
-      tor_free(v);
-      return -1;
-    }
-    if (k && v) {
-      unsigned command = CONFIG_LINE_NORMAL;
-      if (extended) {
-        if (k[0] == '+') {
-          char *k_new = tor_strdup(k+1);
-          tor_free(k);
-          k = k_new;
-          command = CONFIG_LINE_APPEND;
-        } else if (k[0] == '/') {
-          char *k_new = tor_strdup(k+1);
-          tor_free(k);
-          k = k_new;
-          tor_free(v);
-          v = tor_strdup("");
-          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);
-    } else {
-      tor_free(k);
-      tor_free(v);
-    }
-  } while (*string);
-
-  *result = list;
-  return 0;
-}
-
-/**
- * Free all the configuration lines on the linked list <b>front</b>.
- */
-void
-config_free_lines(config_line_t *front)
-{
-  config_line_t *tmp;
-
-  while (front) {
-    tmp = front;
-    front = tmp->next;
-
-    tor_free(tmp->key);
-    tor_free(tmp->value);
-    tor_free(tmp);
-  }
-}
-
-/** As config_find_option, but return a non-const pointer. */
-static config_var_t *
-config_find_option_mutable(config_format_t *fmt, const char *key)
-{
-  int i;
-  size_t keylen = strlen(key);
-  if (!keylen)
-    return NULL; /* if they say "--" on the command line, it's not an option */
-  /* First, check for an exact (case-insensitive) match */
-  for (i=0; fmt->vars[i].name; ++i) {
-    if (!strcasecmp(key, fmt->vars[i].name)) {
-      return &fmt->vars[i];
-    }
-  }
-  /* If none, check for an abbreviated match */
-  for (i=0; fmt->vars[i].name; ++i) {
-    if (!strncasecmp(key, fmt->vars[i].name, keylen)) {
-      log_warn(LD_CONFIG, "The abbreviation '%s' is deprecated. "
-               "Please use '%s' instead",
-               key, fmt->vars[i].name);
-      return &fmt->vars[i];
-    }
-  }
-  /* Okay, unrecognized option */
-  return NULL;
-}
-
-/** If <b>key</b> is a configuration option, return the corresponding const
- * config_var_t.  Otherwise, if <b>key</b> is a non-standard abbreviation,
- * warn, and return the corresponding const config_var_t.  Otherwise return
- * NULL.
- */
-static const config_var_t *
-config_find_option(const config_format_t *fmt, const char *key)
-{
-  return config_find_option_mutable((config_format_t*)fmt, key);
-}
-
-/** Return the number of option entries in <b>fmt</b>. */
-static int
-config_count_options(const config_format_t *fmt)
-{
-  int i;
-  for (i=0; fmt->vars[i].name; ++i)
-    ;
-  return i;
-}
-
-/*
- * Functions to assign config options.
- */
-
-/** <b>c</b>-\>key is known to be a real key. Update <b>options</b>
- * with <b>c</b>-\>value and return 0, or return -1 if bad value.
- *
- * Called from config_assign_line() and option_reset().
- */
-static int
-config_assign_value(const config_format_t *fmt, or_options_t *options,
-                    config_line_t *c, char **msg)
-{
-  int i, ok;
-  const config_var_t *var;
-  void *lvalue;
-
-  CHECK(fmt, options);
-
-  var = config_find_option(fmt, c->key);
-  tor_assert(var);
-
-  lvalue = STRUCT_VAR_P(options, var->var_offset);
-
-  switch (var->type) {
-
-  case CONFIG_TYPE_PORT:
-    if (!strcasecmp(c->value, "auto")) {
-      *(int *)lvalue = CFG_AUTO_PORT;
-      break;
-    }
-    /* fall through */
-  case CONFIG_TYPE_INT:
-  case CONFIG_TYPE_UINT:
-    i = (int)tor_parse_long(c->value, 10,
-                            var->type==CONFIG_TYPE_INT ? INT_MIN : 0,
-                            var->type==CONFIG_TYPE_PORT ? 65535 : INT_MAX,
-                            &ok, NULL);
-    if (!ok) {
-      tor_asprintf(msg,
-          "Int keyword '%s %s' is malformed or out of bounds.",
-          c->key, c->value);
-      return -1;
-    }
-    *(int *)lvalue = i;
-    break;
-
-  case CONFIG_TYPE_INTERVAL: {
-    i = config_parse_interval(c->value, &ok);
-    if (!ok) {
-      tor_asprintf(msg,
-          "Interval '%s %s' is malformed or out of bounds.",
-          c->key, c->value);
-      return -1;
-    }
-    *(int *)lvalue = i;
-    break;
-  }
-
-  case CONFIG_TYPE_MSEC_INTERVAL: {
-    i = config_parse_msec_interval(c->value, &ok);
-    if (!ok) {
-      tor_asprintf(msg,
-          "Msec interval '%s %s' is malformed or out of bounds.",
-          c->key, c->value);
-      return -1;
-    }
-    *(int *)lvalue = i;
-    break;
-  }
-
-  case CONFIG_TYPE_MEMUNIT: {
-    uint64_t u64 = config_parse_memunit(c->value, &ok);
-    if (!ok) {
-      tor_asprintf(msg,
-          "Value '%s %s' is malformed or out of bounds.",
-          c->key, c->value);
-      return -1;
-    }
-    *(uint64_t *)lvalue = u64;
-    break;
-  }
-
-  case CONFIG_TYPE_BOOL:
-    i = (int)tor_parse_long(c->value, 10, 0, 1, &ok, NULL);
-    if (!ok) {
-      tor_asprintf(msg,
-          "Boolean '%s %s' expects 0 or 1.",
-          c->key, c->value);
-      return -1;
-    }
-    *(int *)lvalue = i;
-    break;
-
-  case CONFIG_TYPE_AUTOBOOL:
-    if (!strcmp(c->value, "auto"))
-      *(int *)lvalue = -1;
-    else if (!strcmp(c->value, "0"))
-      *(int *)lvalue = 0;
-    else if (!strcmp(c->value, "1"))
-      *(int *)lvalue = 1;
-    else {
-      tor_asprintf(msg, "Boolean '%s %s' expects 0, 1, or 'auto'.",
-                   c->key, c->value);
-      return -1;
-    }
-    break;
-
-  case CONFIG_TYPE_STRING:
-  case CONFIG_TYPE_FILENAME:
-    tor_free(*(char **)lvalue);
-    *(char **)lvalue = tor_strdup(c->value);
-    break;
-
-  case CONFIG_TYPE_DOUBLE:
-    *(double *)lvalue = atof(c->value);
-    break;
-
-  case CONFIG_TYPE_ISOTIME:
-    if (parse_iso_time(c->value, (time_t *)lvalue)) {
-      tor_asprintf(msg,
-          "Invalid time '%s' for keyword '%s'", c->value, c->key);
-      return -1;
-    }
-    break;
-
-  case CONFIG_TYPE_ROUTERSET:
-    if (*(routerset_t**)lvalue) {
-      routerset_free(*(routerset_t**)lvalue);
-    }
-    *(routerset_t**)lvalue = routerset_new();
-    if (routerset_parse(*(routerset_t**)lvalue, c->value, c->key)<0) {
-      tor_asprintf(msg, "Invalid exit list '%s' for option '%s'",
-                   c->value, c->key);
-      return -1;
-    }
-    break;
-
-  case CONFIG_TYPE_CSV:
-    if (*(smartlist_t**)lvalue) {
-      SMARTLIST_FOREACH(*(smartlist_t**)lvalue, char *, cp, tor_free(cp));
-      smartlist_clear(*(smartlist_t**)lvalue);
-    } else {
-      *(smartlist_t**)lvalue = smartlist_new();
-    }
-
-    smartlist_split_string(*(smartlist_t**)lvalue, c->value, ",",
-                           SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
-    break;
-
-  case CONFIG_TYPE_LINELIST:
-  case CONFIG_TYPE_LINELIST_S:
-    {
-      config_line_t *lastval = *(config_line_t**)lvalue;
-      if (lastval && lastval->fragile) {
-        if (c->command != CONFIG_LINE_APPEND) {
-          config_free_lines(lastval);
-          *(config_line_t**)lvalue = NULL;
-        } else {
-          lastval->fragile = 0;
-        }
-      }
-
-      config_line_append((config_line_t**)lvalue, c->key, c->value);
-    }
-    break;
-  case CONFIG_TYPE_OBSOLETE:
-    log_warn(LD_CONFIG, "Skipping obsolete configuration option '%s'", c->key);
-    break;
-  case CONFIG_TYPE_LINELIST_V:
-    tor_asprintf(msg,
-        "You may not provide a value for virtual option '%s'", c->key);
-    return -1;
-  default:
-    tor_assert(0);
-    break;
-  }
-  return 0;
-}
-
-/** Mark every linelist in <b>options</b> "fragile", so that fresh assignments
- * to it will replace old ones. */
-static void
-config_mark_lists_fragile(const config_format_t *fmt, or_options_t *options)
-{
-  int i;
-  tor_assert(fmt);
-  tor_assert(options);
-
-  for (i = 0; fmt->vars[i].name; ++i) {
-    const config_var_t *var = &fmt->vars[i];
-    config_line_t *list;
-    if (var->type != CONFIG_TYPE_LINELIST &&
-        var->type != CONFIG_TYPE_LINELIST_V)
-      continue;
-
-    list = *(config_line_t **)STRUCT_VAR_P(options, var->var_offset);
-    if (list)
-      list->fragile = 1;
-  }
-}
-
-/** If <b>c</b> is a syntactically valid configuration line, update
- * <b>options</b> with its value and return 0.  Otherwise return -1 for bad
- * key, -2 for bad value.
- *
- * If <b>clear_first</b> is set, clear the value first. Then if
- * <b>use_defaults</b> is set, set the value to the default.
- *
- * Called from config_assign().
- */
-static int
-config_assign_line(const config_format_t *fmt, or_options_t *options,
-                   config_line_t *c, int use_defaults,
-                   int clear_first, bitarray_t *options_seen, char **msg)
-{
-  const config_var_t *var;
-
-  CHECK(fmt, options);
-
-  var = config_find_option(fmt, c->key);
-  if (!var) {
-    if (fmt->extra) {
-      void *lvalue = STRUCT_VAR_P(options, fmt->extra->var_offset);
-      log_info(LD_CONFIG,
-               "Found unrecognized option '%s'; saving it.", c->key);
-      config_line_append((config_line_t**)lvalue, c->key, c->value);
-      return 0;
-    } else {
-      tor_asprintf(msg,
-                "Unknown option '%s'.  Failing.", c->key);
-      return -1;
-    }
-  }
-
-  /* Put keyword into canonical case. */
-  if (strcmp(var->name, c->key)) {
-    tor_free(c->key);
-    c->key = tor_strdup(var->name);
-  }
-
-  if (!strlen(c->value)) {
-    /* reset or clear it, then return */
-    if (!clear_first) {
-      if ((var->type == CONFIG_TYPE_LINELIST ||
-           var->type == CONFIG_TYPE_LINELIST_S) &&
-          c->command != CONFIG_LINE_CLEAR) {
-        /* We got an empty linelist from the torrc or command line.
-           As a special case, call this an error. Warn and ignore. */
-        log_warn(LD_CONFIG,
-                 "Linelist option '%s' has no value. Skipping.", c->key);
-      } else { /* not already cleared */
-        option_reset(fmt, options, var, use_defaults);
-      }
-    }
-    return 0;
-  } else if (c->command == CONFIG_LINE_CLEAR && !clear_first) {
-    option_reset(fmt, options, var, use_defaults);
-  }
-
-  if (options_seen && (var->type != CONFIG_TYPE_LINELIST &&
-                       var->type != CONFIG_TYPE_LINELIST_S)) {
-    /* We're tracking which options we've seen, and this option is not
-     * supposed to occur more than once. */
-    int var_index = (int)(var - fmt->vars);
-    if (bitarray_is_set(options_seen, var_index)) {
-      log_warn(LD_CONFIG, "Option '%s' used more than once; all but the last "
-               "value will be ignored.", var->name);
-    }
-    bitarray_set(options_seen, var_index);
-  }
-
-  if (config_assign_value(fmt, options, c, msg) < 0)
-    return -2;
-  return 0;
-}
-
-/** Restore the option named <b>key</b> in options to its default value.
- * Called from config_assign(). */
-static void
-config_reset_line(const config_format_t *fmt, or_options_t *options,
-                  const char *key, int use_defaults)
-{
-  const config_var_t *var;
-
-  CHECK(fmt, options);
-
-  var = config_find_option(fmt, key);
-  if (!var)
-    return; /* give error on next pass. */
-
-  option_reset(fmt, options, var, use_defaults);
-}
-
 /** Return true iff key is a valid configuration option. */
 int
 option_is_recognized(const char *key)
@@ -2417,287 +1824,7 @@ option_get_canonical_name(const char *key)
 config_line_t *
 option_get_assignment(const or_options_t *options, const char *key)
 {
-  return get_assigned_option(&options_format, options, key, 1);
-}
-
-/** Return true iff value needs to be quoted and escaped to be used in
- * a configuration file. */
-static int
-config_value_needs_escape(const char *value)
-{
-  if (*value == '\"')
-    return 1;
-  while (*value) {
-    switch (*value)
-    {
-    case '\r':
-    case '\n':
-    case '#':
-      /* Note: quotes and backspaces need special handling when we are using
-       * quotes, not otherwise, so they don't trigger escaping on their
-       * own. */
-      return 1;
-    default:
-      if (!TOR_ISPRINT(*value))
-        return 1;
-    }
-    ++value;
-  }
-  return 0;
-}
-
-/** Return a newly allocated deep copy of the lines in <b>inp</b>. */
-static config_line_t *
-config_lines_dup(const config_line_t *inp)
-{
-  config_line_t *result = NULL;
-  config_line_t **next_out = &result;
-  while (inp) {
-    *next_out = tor_malloc_zero(sizeof(config_line_t));
-    (*next_out)->key = tor_strdup(inp->key);
-    (*next_out)->value = tor_strdup(inp->value);
-    inp = inp->next;
-    next_out = &((*next_out)->next);
-  }
-  (*next_out) = NULL;
-  return result;
-}
-
-/** Return newly allocated line or lines corresponding to <b>key</b> in the
- * configuration <b>options</b>.  If <b>escape_val</b> is true and a
- * value needs to be quoted before it's put in a config file, quote and
- * escape that value. Return NULL if no such key exists. */
-static config_line_t *
-get_assigned_option(const config_format_t *fmt, const void *options,
-                    const char *key, int escape_val)
-{
-  const config_var_t *var;
-  const void *value;
-  config_line_t *result;
-  tor_assert(options && key);
-
-  CHECK(fmt, options);
-
-  var = config_find_option(fmt, key);
-  if (!var) {
-    log_warn(LD_CONFIG, "Unknown option '%s'.  Failing.", key);
-    return NULL;
-  }
-  value = STRUCT_VAR_P(options, var->var_offset);
-
-  result = tor_malloc_zero(sizeof(config_line_t));
-  result->key = tor_strdup(var->name);
-  switch (var->type)
-    {
-    case CONFIG_TYPE_STRING:
-    case CONFIG_TYPE_FILENAME:
-      if (*(char**)value) {
-        result->value = tor_strdup(*(char**)value);
-      } else {
-        tor_free(result->key);
-        tor_free(result);
-        return NULL;
-      }
-      break;
-    case CONFIG_TYPE_ISOTIME:
-      if (*(time_t*)value) {
-        result->value = tor_malloc(ISO_TIME_LEN+1);
-        format_iso_time(result->value, *(time_t*)value);
-      } else {
-        tor_free(result->key);
-        tor_free(result);
-      }
-      escape_val = 0; /* Can't need escape. */
-      break;
-    case CONFIG_TYPE_PORT:
-      if (*(int*)value == CFG_AUTO_PORT) {
-        result->value = tor_strdup("auto");
-        escape_val = 0;
-        break;
-      }
-      /* fall through */
-    case CONFIG_TYPE_INTERVAL:
-    case CONFIG_TYPE_MSEC_INTERVAL:
-    case CONFIG_TYPE_UINT:
-    case CONFIG_TYPE_INT:
-      /* This means every or_options_t uint or bool element
-       * needs to be an int. Not, say, a uint16_t or char. */
-      tor_asprintf(&result->value, "%d", *(int*)value);
-      escape_val = 0; /* Can't need escape. */
-      break;
-    case CONFIG_TYPE_MEMUNIT:
-      tor_asprintf(&result->value, U64_FORMAT,
-                   U64_PRINTF_ARG(*(uint64_t*)value));
-      escape_val = 0; /* Can't need escape. */
-      break;
-    case CONFIG_TYPE_DOUBLE:
-      tor_asprintf(&result->value, "%f", *(double*)value);
-      escape_val = 0; /* Can't need escape. */
-      break;
-
-    case CONFIG_TYPE_AUTOBOOL:
-      if (*(int*)value == -1) {
-        result->value = tor_strdup("auto");
-        escape_val = 0;
-        break;
-      }
-      /* fall through */
-    case CONFIG_TYPE_BOOL:
-      result->value = tor_strdup(*(int*)value ? "1" : "0");
-      escape_val = 0; /* Can't need escape. */
-      break;
-    case CONFIG_TYPE_ROUTERSET:
-      result->value = routerset_to_string(*(routerset_t**)value);
-      break;
-    case CONFIG_TYPE_CSV:
-      if (*(smartlist_t**)value)
-        result->value =
-          smartlist_join_strings(*(smartlist_t**)value, ",", 0, NULL);
-      else
-        result->value = tor_strdup("");
-      break;
-    case CONFIG_TYPE_OBSOLETE:
-      log_fn(LOG_PROTOCOL_WARN, LD_CONFIG,
-             "You asked me for the value of an obsolete config option '%s'.",
-             key);
-      tor_free(result->key);
-      tor_free(result);
-      return NULL;
-    case CONFIG_TYPE_LINELIST_S:
-      log_warn(LD_CONFIG,
-               "Can't return context-sensitive '%s' on its own", key);
-      tor_free(result->key);
-      tor_free(result);
-      return NULL;
-    case CONFIG_TYPE_LINELIST:
-    case CONFIG_TYPE_LINELIST_V:
-      tor_free(result->key);
-      tor_free(result);
-      result = config_lines_dup(*(const config_line_t**)value);
-      break;
-    default:
-      tor_free(result->key);
-      tor_free(result);
-      log_warn(LD_BUG,"Unknown type %d for known key '%s'",
-               var->type, key);
-      return NULL;
-    }
-
-  if (escape_val) {
-    config_line_t *line;
-    for (line = result; line; line = line->next) {
-      if (line->value && config_value_needs_escape(line->value)) {
-        char *newval = esc_for_log(line->value);
-        tor_free(line->value);
-        line->value = newval;
-      }
-    }
-  }
-
-  return result;
-}
-
-/** Iterate through the linked list of requested options <b>list</b>.
- * For each item, convert as appropriate and assign to <b>options</b>.
- * If an item is unrecognized, set *msg and return -1 immediately,
- * else return 0 for success.
- *
- * If <b>clear_first</b>, interpret config options as replacing (not
- * extending) their previous values. If <b>clear_first</b> is set,
- * then <b>use_defaults</b> to decide if you set to defaults after
- * clearing, or make the value 0 or NULL.
- *
- * Here are the use cases:
- * 1. A non-empty AllowInvalid line in your torrc. Appends to current
- *    if linelist, replaces current if csv.
- * 2. An empty AllowInvalid line in your torrc. Should clear it.
- * 3. "RESETCONF AllowInvalid" sets it to default.
- * 4. "SETCONF AllowInvalid" makes it NULL.
- * 5. "SETCONF AllowInvalid=foo" clears it and sets it to "foo".
- *
- * Use_defaults   Clear_first
- *    0                0       "append"
- *    1                0       undefined, don't use
- *    0                1       "set to null first"
- *    1                1       "set to defaults first"
- * Return 0 on success, -1 on bad key, -2 on bad value.
- *
- * As an additional special case, if a LINELIST config option has
- * no value and clear_first is 0, then warn and ignore it.
- */
-
-/*
-There are three call cases for config_assign() currently.
-
-Case one: Torrc entry
-options_init_from_torrc() calls config_assign(0, 0)
-  calls config_assign_line(0, 0).
-    if value is empty, calls option_reset(0) and returns.
-    calls config_assign_value(), appends.
-
-Case two: setconf
-options_trial_assign() calls config_assign(0, 1)
-  calls config_reset_line(0)
-    calls option_reset(0)
-      calls option_clear().
-  calls config_assign_line(0, 1).
-    if value is empty, returns.
-    calls config_assign_value(), appends.
-
-Case three: resetconf
-options_trial_assign() calls config_assign(1, 1)
-  calls config_reset_line(1)
-    calls option_reset(1)
-      calls option_clear().
-      calls config_assign_value(default)
-  calls config_assign_line(1, 1).
-    returns.
-*/
-static int
-config_assign(const config_format_t *fmt, void *options, config_line_t *list,
-              int use_defaults, int clear_first, char **msg)
-{
-  config_line_t *p;
-  bitarray_t *options_seen;
-  const int n_options = config_count_options(fmt);
-
-  CHECK(fmt, options);
-
-  /* pass 1: normalize keys */
-  for (p = list; p; p = p->next) {
-    const char *full = expand_abbrev(fmt, p->key, 0, 1);
-    if (strcmp(full,p->key)) {
-      tor_free(p->key);
-      p->key = tor_strdup(full);
-    }
-  }
-
-  /* pass 2: if we're reading from a resetting source, clear all
-   * mentioned config options, and maybe set to their defaults. */
-  if (clear_first) {
-    for (p = list; p; p = p->next)
-      config_reset_line(fmt, options, p->key, use_defaults);
-  }
-
-  options_seen = bitarray_init_zero(n_options);
-  /* pass 3: assign. */
-  while (list) {
-    int r;
-    if ((r=config_assign_line(fmt, options, list, use_defaults,
-                              clear_first, options_seen, msg))) {
-      bitarray_free(options_seen);
-      return r;
-    }
-    list = list->next;
-  }
-  bitarray_free(options_seen);
-
-  /** Now we're done assigning a group of options to the configuration.
-   * Subsequent group assignments should _replace_ linelists, not extend
-   * them. */
-  config_mark_lists_fragile(fmt, options);
-
-  return 0;
+  return config_get_assigned_option(&options_format, options, key, 1);
 }
 
 /** Try assigning <b>list</b> to the global options. You do this by duping
@@ -2714,7 +1841,7 @@ options_trial_assign(config_line_t *list, int use_defaults,
                      int clear_first, char **msg)
 {
   int r;
-  or_options_t *trial_options = options_dup(&options_format, get_options());
+  or_options_t *trial_options = config_dup(&options_format, get_options());
 
   if ((r=config_assign(&options_format, trial_options,
                        list, use_defaults, clear_first, msg)) < 0) {
@@ -2741,90 +1868,6 @@ options_trial_assign(config_line_t *list, int use_defaults,
   return SETOPT_OK;
 }
 
-/** Reset config option <b>var</b> to 0, 0.0, NULL, or the equivalent.
- * Called from option_reset() and config_free(). */
-static void
-option_clear(const config_format_t *fmt, or_options_t *options,
-             const config_var_t *var)
-{
-  void *lvalue = STRUCT_VAR_P(options, var->var_offset);
-  (void)fmt; /* unused */
-  switch (var->type) {
-    case CONFIG_TYPE_STRING:
-    case CONFIG_TYPE_FILENAME:
-      tor_free(*(char**)lvalue);
-      break;
-    case CONFIG_TYPE_DOUBLE:
-      *(double*)lvalue = 0.0;
-      break;
-    case CONFIG_TYPE_ISOTIME:
-      *(time_t*)lvalue = 0;
-      break;
-    case CONFIG_TYPE_INTERVAL:
-    case CONFIG_TYPE_MSEC_INTERVAL:
-    case CONFIG_TYPE_UINT:
-    case CONFIG_TYPE_INT:
-    case CONFIG_TYPE_PORT:
-    case CONFIG_TYPE_BOOL:
-      *(int*)lvalue = 0;
-      break;
-    case CONFIG_TYPE_AUTOBOOL:
-      *(int*)lvalue = -1;
-      break;
-    case CONFIG_TYPE_MEMUNIT:
-      *(uint64_t*)lvalue = 0;
-      break;
-    case CONFIG_TYPE_ROUTERSET:
-      if (*(routerset_t**)lvalue) {
-        routerset_free(*(routerset_t**)lvalue);
-        *(routerset_t**)lvalue = NULL;
-      }
-      break;
-    case CONFIG_TYPE_CSV:
-      if (*(smartlist_t**)lvalue) {
-        SMARTLIST_FOREACH(*(smartlist_t **)lvalue, char *, cp, tor_free(cp));
-        smartlist_free(*(smartlist_t **)lvalue);
-        *(smartlist_t **)lvalue = NULL;
-      }
-      break;
-    case CONFIG_TYPE_LINELIST:
-    case CONFIG_TYPE_LINELIST_S:
-      config_free_lines(*(config_line_t **)lvalue);
-      *(config_line_t **)lvalue = NULL;
-      break;
-    case CONFIG_TYPE_LINELIST_V:
-      /* handled by linelist_s. */
-      break;
-    case CONFIG_TYPE_OBSOLETE:
-      break;
-  }
-}
-
-/** Clear the option indexed by <b>var</b> in <b>options</b>. Then if
- * <b>use_defaults</b>, set it to its default value.
- * Called by config_init() and option_reset_line() and option_assign_line(). */
-static void
-option_reset(const config_format_t *fmt, or_options_t *options,
-             const config_var_t *var, int use_defaults)
-{
-  config_line_t *c;
-  char *msg = NULL;
-  CHECK(fmt, options);
-  option_clear(fmt, options, var); /* clear it first */
-  if (!use_defaults)
-    return; /* all done */
-  if (var->initvalue) {
-    c = tor_malloc_zero(sizeof(config_line_t));
-    c->key = tor_strdup(var->name);
-    c->value = tor_strdup(var->initvalue);
-    if (config_assign_value(fmt, options, c, &msg) < 0) {
-      log_warn(LD_BUG, "Failed to assign default: %s", msg);
-      tor_free(msg); /* if this happens it's a bug */
-    }
-    config_free_lines(c);
-  }
-}
-
 /** Print a usage message for tor. */
 static void
 print_usage(void)
@@ -3039,107 +2082,6 @@ is_local_addr(const tor_addr_t *addr)
   return 0;
 }
 
-/** Release storage held by <b>options</b>. */
-static void
-config_free(const config_format_t *fmt, void *options)
-{
-  int i;
-
-  if (!options)
-    return;
-
-  tor_assert(fmt);
-
-  for (i=0; fmt->vars[i].name; ++i)
-    option_clear(fmt, options, &(fmt->vars[i]));
-  if (fmt->extra) {
-    config_line_t **linep = STRUCT_VAR_P(options, fmt->extra->var_offset);
-    config_free_lines(*linep);
-    *linep = NULL;
-  }
-  tor_free(options);
-}
-
-/** Return true iff a and b contain identical keys and values in identical
- * order. */
-static int
-config_lines_eq(config_line_t *a, config_line_t *b)
-{
-  while (a && b) {
-    if (strcasecmp(a->key, b->key) || strcmp(a->value, b->value))
-      return 0;
-    a = a->next;
-    b = b->next;
-  }
-  if (a || b)
-    return 0;
-  return 1;
-}
-
-/** Return the number of lines in <b>a</b> whose key is <b>key</b>. */
-static int
-config_count_key(const config_line_t *a, const char *key)
-{
-  int n = 0;
-  while (a) {
-    if (!strcasecmp(a->key, key)) {
-      ++n;
-    }
-    a = a->next;
-  }
-  return n;
-}
-
-/** Return true iff the option <b>name</b> has the same value in <b>o1</b>
- * and <b>o2</b>.  Must not be called for LINELIST_S or OBSOLETE options.
- */
-static int
-option_is_same(const config_format_t *fmt,
-               const or_options_t *o1, const or_options_t *o2,
-               const char *name)
-{
-  config_line_t *c1, *c2;
-  int r = 1;
-  CHECK(fmt, o1);
-  CHECK(fmt, o2);
-
-  c1 = get_assigned_option(fmt, o1, name, 0);
-  c2 = get_assigned_option(fmt, o2, name, 0);
-  r = config_lines_eq(c1, c2);
-  config_free_lines(c1);
-  config_free_lines(c2);
-  return r;
-}
-
-/** Copy storage held by <b>old</b> into a new or_options_t and return it. */
-static or_options_t *
-options_dup(const config_format_t *fmt, const or_options_t *old)
-{
-  or_options_t *newopts;
-  int i;
-  config_line_t *line;
-
-  newopts = config_new(fmt);
-  for (i=0; fmt->vars[i].name; ++i) {
-    if (fmt->vars[i].type == CONFIG_TYPE_LINELIST_S)
-      continue;
-    if (fmt->vars[i].type == CONFIG_TYPE_OBSOLETE)
-      continue;
-    line = get_assigned_option(fmt, old, fmt->vars[i].name, 0);
-    if (line) {
-      char *msg = NULL;
-      if (config_assign(fmt, newopts, line, 0, 0, &msg) < 0) {
-        log_err(LD_BUG, "Config_get_assigned_option() generated "
-                "something we couldn't config_assign(): %s", msg);
-        tor_free(msg);
-        tor_assert(0);
-      }
-    }
-    config_free_lines(line);
-  }
-  return newopts;
-}
-
 /** Return a new empty or_options_t.  Used for testing. */
 or_options_t *
 options_new(void)
@@ -3155,94 +2097,6 @@ options_init(or_options_t *options)
   config_init(&options_format, options);
 }
 
-/** Set all vars in the configuration object <b>options</b> to their default
- * values. */
-static void
-config_init(const config_format_t *fmt, void *options)
-{
-  int i;
-  const config_var_t *var;
-  CHECK(fmt, options);
-
-  for (i=0; fmt->vars[i].name; ++i) {
-    var = &fmt->vars[i];
-    if (!var->initvalue)
-      continue; /* defaults to NULL or 0 */
-    option_reset(fmt, options, var, 1);
-  }
-}
-
-/** Allocate and return a new string holding the written-out values of the vars
- * in 'options'.  If 'minimal', do not write out any default-valued vars.
- * Else, if comment_defaults, write default values as comments.
- */
-static char *
-config_dump(const config_format_t *fmt, const void *default_options,
-            const void *options, int minimal,
-            int comment_defaults)
-{
-  smartlist_t *elements;
-  const or_options_t *defaults = default_options;
-  void *defaults_tmp = NULL;
-  config_line_t *line, *assigned;
-  char *result;
-  int i;
-  char *msg = NULL;
-
-  if (defaults == NULL) {
-    defaults = defaults_tmp = config_new(fmt);
-    config_init(fmt, defaults_tmp);
-  }
-
-  /* XXX use a 1 here so we don't add a new log line while dumping */
-  if (default_options == NULL) {
-    if (fmt->validate_fn(NULL, defaults_tmp, 1, &msg) < 0) {
-      log_err(LD_BUG, "Failed to validate default config.");
-      tor_free(msg);
-      tor_assert(0);
-    }
-  }
-
-  elements = smartlist_new();
-  for (i=0; fmt->vars[i].name; ++i) {
-    int comment_option = 0;
-    if (fmt->vars[i].type == CONFIG_TYPE_OBSOLETE ||
-        fmt->vars[i].type == CONFIG_TYPE_LINELIST_S)
-      continue;
-    /* Don't save 'hidden' control variables. */
-    if (!strcmpstart(fmt->vars[i].name, "__"))
-      continue;
-    if (minimal && option_is_same(fmt, options, defaults, fmt->vars[i].name))
-      continue;
-    else if (comment_defaults &&
-             option_is_same(fmt, options, defaults, fmt->vars[i].name))
-      comment_option = 1;
-
-    line = assigned = get_assigned_option(fmt, options, fmt->vars[i].name, 1);
-
-    for (; line; line = line->next) {
-      smartlist_add_asprintf(elements, "%s%s %s\n",
-                   comment_option ? "# " : "",
-                   line->key, line->value);
-    }
-    config_free_lines(assigned);
-  }
-
-  if (fmt->extra) {
-    line = *(config_line_t**)STRUCT_VAR_P(options, fmt->extra->var_offset);
-    for (; line; line = line->next) {
-      smartlist_add_asprintf(elements, "%s %s\n", line->key, line->value);
-    }
-  }
-
-  result = smartlist_join_strings(elements, "", 0, NULL);
-  SMARTLIST_FOREACH(elements, char *, cp, tor_free(cp));
-  smartlist_free(elements);
-  if (defaults_tmp)
-    config_free(fmt, defaults_tmp);
-  return result;
-}
-
 /** Return a string containing a possible configuration file that would give
  * the configuration in <b>options</b>.  If <b>minimal</b> is true, do not
  * include options that are the same as Tor's defaults.
@@ -4753,7 +3607,7 @@ options_init_from_string(const char *cf_defaults, const char *cf,
       goto err;
     }
     if (i==0)
-      newdefaultoptions = options_dup(&options_format, newoptions);
+      newdefaultoptions = config_dup(&options_format, newoptions);
   }
 
   /* Go through command-line variables too */
@@ -4814,7 +3668,7 @@ options_init_from_string(const char *cf_defaults, const char *cf,
         goto err;
       }
       if (i==0)
-        newdefaultoptions = options_dup(&options_format, newoptions);
+        newdefaultoptions = config_dup(&options_format, newoptions);
     }
     /* Assign command-line variables a second time too */
     retval = config_assign(&options_format, newoptions,
@@ -6484,180 +5338,6 @@ options_save_current(void)
   return write_configuration_file(get_torrc_fname(0), get_options());
 }
 
-/** Mapping from a unit name to a multiplier for converting that unit into a
- * base unit.  Used by config_parse_unit. */
-struct unit_table_t {
-  const char *unit; /**< The name of the unit */
-  uint64_t multiplier; /**< How many of the base unit appear in this unit */
-};
-
-/** Table to map the names of memory units to the number of bytes they
- * contain. */
-static struct unit_table_t memory_units[] = {
-  { "",          1 },
-  { "b",         1<< 0 },
-  { "byte",      1<< 0 },
-  { "bytes",     1<< 0 },
-  { "kb",        1<<10 },
-  { "kbyte",     1<<10 },
-  { "kbytes",    1<<10 },
-  { "kilobyte",  1<<10 },
-  { "kilobytes", 1<<10 },
-  { "m",         1<<20 },
-  { "mb",        1<<20 },
-  { "mbyte",     1<<20 },
-  { "mbytes",    1<<20 },
-  { "megabyte",  1<<20 },
-  { "megabytes", 1<<20 },
-  { "gb",        1<<30 },
-  { "gbyte",     1<<30 },
-  { "gbytes",    1<<30 },
-  { "gigabyte",  1<<30 },
-  { "gigabytes", 1<<30 },
-  { "tb",        U64_LITERAL(1)<<40 },
-  { "terabyte",  U64_LITERAL(1)<<40 },
-  { "terabytes", U64_LITERAL(1)<<40 },
-  { NULL, 0 },
-};
-
-/** Table to map the names of time units to the number of seconds they
- * contain. */
-static struct unit_table_t time_units[] = {
-  { "",         1 },
-  { "second",   1 },
-  { "seconds",  1 },
-  { "minute",   60 },
-  { "minutes",  60 },
-  { "hour",     60*60 },
-  { "hours",    60*60 },
-  { "day",      24*60*60 },
-  { "days",     24*60*60 },
-  { "week",     7*24*60*60 },
-  { "weeks",    7*24*60*60 },
-  { NULL, 0 },
-};
-
-/** Table to map the names of time units to the number of milliseconds
- * they contain. */
-static struct unit_table_t time_msec_units[] = {
-  { "",         1 },
-  { "msec",     1 },
-  { "millisecond", 1 },
-  { "milliseconds", 1 },
-  { "second",   1000 },
-  { "seconds",  1000 },
-  { "minute",   60*1000 },
-  { "minutes",  60*1000 },
-  { "hour",     60*60*1000 },
-  { "hours",    60*60*1000 },
-  { "day",      24*60*60*1000 },
-  { "days",     24*60*60*1000 },
-  { "week",     7*24*60*60*1000 },
-  { "weeks",    7*24*60*60*1000 },
-  { NULL, 0 },
-};
-
-/** Parse a string <b>val</b> containing a number, zero or more
- * spaces, and an optional unit string.  If the unit appears in the
- * table <b>u</b>, then multiply the number by the unit multiplier.
- * On success, set *<b>ok</b> to 1 and return this product.
- * Otherwise, set *<b>ok</b> to 0.
- */
-static uint64_t
-config_parse_units(const char *val, struct unit_table_t *u, int *ok)
-{
-  uint64_t v = 0;
-  double d = 0;
-  int use_float = 0;
-  char *cp;
-
-  tor_assert(ok);
-
-  v = tor_parse_uint64(val, 10, 0, UINT64_MAX, ok, &cp);
-  if (!*ok || (cp && *cp == '.')) {
-    d = tor_parse_double(val, 0, UINT64_MAX, ok, &cp);
-    if (!*ok)
-      goto done;
-    use_float = 1;
-  }
-
-  if (!cp) {
-    *ok = 1;
-    v = use_float ? DBL_TO_U64(d) :  v;
-    goto done;
-  }
-
-  cp = (char*) eat_whitespace(cp);
-
-  for ( ;u->unit;++u) {
-    if (!strcasecmp(u->unit, cp)) {
-      if (use_float)
-        v = u->multiplier * d;
-      else
-        v *= u->multiplier;
-      *ok = 1;
-      goto done;
-    }
-  }
-  log_warn(LD_CONFIG, "Unknown unit '%s'.", cp);
-  *ok = 0;
- done:
-
-  if (*ok)
-    return v;
-  else
-    return 0;
-}
-
-/** Parse a string in the format "number unit", where unit is a unit of
- * information (byte, KB, M, etc).  On success, set *<b>ok</b> to true
- * and return the number of bytes specified.  Otherwise, set
- * *<b>ok</b> to false and return 0. */
-static uint64_t
-config_parse_memunit(const char *s, int *ok)
-{
-  uint64_t u = config_parse_units(s, memory_units, ok);
-  return u;
-}
-
-/** Parse a string in the format "number unit", where unit is a unit of
- * time in milliseconds.  On success, set *<b>ok</b> to true and return
- * the number of milliseconds in the provided interval.  Otherwise, set
- * *<b>ok</b> to 0 and return -1. */
-static int
-config_parse_msec_interval(const char *s, int *ok)
-{
-  uint64_t r;
-  r = config_parse_units(s, time_msec_units, ok);
-  if (!ok)
-    return -1;
-  if (r > INT_MAX) {
-    log_warn(LD_CONFIG, "Msec interval '%s' is too long", s);
-    *ok = 0;
-    return -1;
-  }
-  return (int)r;
-}
-
-/** Parse a string in the format "number unit", where unit is a unit of time.
- * On success, set *<b>ok</b> to true and return the number of seconds in
- * the provided interval.  Otherwise, set *<b>ok</b> to 0 and return -1.
- */
-static int
-config_parse_interval(const char *s, int *ok)
-{
-  uint64_t r;
-  r = config_parse_units(s, time_units, ok);
-  if (!ok)
-    return -1;
-  if (r > INT_MAX) {
-    log_warn(LD_CONFIG, "Interval '%s' is too long", s);
-    *ok = 0;
-    return -1;
-  }
-  return (int)r;
-}
-
 /** Return the number of cpus configured in <b>options</b>.  If we are
  * told to auto-detect the number of cpus, return the auto-detected number. */
 int
diff --git a/src/or/config.h b/src/or/config.h
index d20796584..abfbef792 100644
--- a/src/or/config.h
+++ b/src/or/config.h
@@ -23,11 +23,9 @@ const char *escaped_safe_str_client(const char *address);
 const char *escaped_safe_str(const char *address);
 const char *get_version(void);
 const char *get_short_version(void);
-
-int config_get_lines(const char *string, config_line_t **result, int extended);
-void config_free_lines(config_line_t *front);
 setopt_err_t options_trial_assign(config_line_t *list, int use_defaults,
                                   int clear_first, char **msg);
+
 int resolve_my_address(int warn_severity, const or_options_t *options,
                        uint32_t *addr, char **hostname_out);
 int is_local_addr(const tor_addr_t *addr);
diff --git a/src/or/confparse.c b/src/or/confparse.c
new file mode 100644
index 000000000..b4f06ce2b
--- /dev/null
+++ b/src/or/confparse.c
@@ -0,0 +1,1226 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2012, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "or.h"
+#include "confparse.h"
+#include "routerlist.h"
+
+static uint64_t config_parse_memunit(const char *s, int *ok);
+static int config_parse_msec_interval(const char *s, int *ok);
+static int config_parse_interval(const char *s, int *ok);
+static void config_reset(const config_format_t *fmt, void *options,
+                         const config_var_t *var, int use_defaults);
+
+/** Allocate an empty configuration object of a given format type. */
+void *
+config_new(const config_format_t *fmt)
+{
+  void *opts = tor_malloc_zero(fmt->size);
+  *(uint32_t*)STRUCT_VAR_P(opts, fmt->magic_offset) = fmt->magic;
+  CONFIG_CHECK(fmt, opts);
+  return opts;
+}
+
+/*
+ * Functions to parse config options
+ */
+
+/** If <b>option</b> is an official abbreviation for a longer option,
+ * return the longer option.  Otherwise return <b>option</b>.
+ * If <b>command_line</b> is set, apply all abbreviations.  Otherwise, only
+ * apply abbreviations that work for the config file and the command line.
+ * If <b>warn_obsolete</b> is set, warn about deprecated names. */
+const char *
+config_expand_abbrev(const config_format_t *fmt, const char *option,
+                     int command_line, int warn_obsolete)
+{
+  int i;
+  if (! fmt->abbrevs)
+    return option;
+  for (i=0; fmt->abbrevs[i].abbreviated; ++i) {
+    /* Abbreviations are case insensitive. */
+    if (!strcasecmp(option,fmt->abbrevs[i].abbreviated) &&
+        (command_line || !fmt->abbrevs[i].commandline_only)) {
+      if (warn_obsolete && fmt->abbrevs[i].warn) {
+        log_warn(LD_CONFIG,
+                 "The configuration option '%s' is deprecated; "
+                 "use '%s' instead.",
+                 fmt->abbrevs[i].abbreviated,
+                 fmt->abbrevs[i].full);
+      }
+      /* Keep going through the list in case we want to rewrite it more.
+       * (We could imagine recursing here, but I don't want to get the
+       * user into an infinite loop if we craft our list wrong.) */
+      option = fmt->abbrevs[i].full;
+    }
+  }
+  return option;
+}
+
+/** Helper: allocate a new configuration option mapping 'key' to 'val',
+ * append it to *<b>lst</b>. */
+void
+config_line_append(config_line_t **lst,
+                   const char *key,
+                   const char *val)
+{
+  config_line_t *newline;
+
+  newline = tor_malloc_zero(sizeof(config_line_t));
+  newline->key = tor_strdup(key);
+  newline->value = tor_strdup(val);
+  newline->next = NULL;
+  while (*lst)
+    lst = &((*lst)->next);
+
+  (*lst) = newline;
+}
+
+/** 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)
+{
+  config_line_t *list = NULL, **next;
+  char *k, *v;
+
+  next = &list;
+  do {
+    k = v = NULL;
+    string = parse_config_line_from_str(string, &k, &v);
+    if (!string) {
+      config_free_lines(list);
+      tor_free(k);
+      tor_free(v);
+      return -1;
+    }
+    if (k && v) {
+      unsigned command = CONFIG_LINE_NORMAL;
+      if (extended) {
+        if (k[0] == '+') {
+          char *k_new = tor_strdup(k+1);
+          tor_free(k);
+          k = k_new;
+          command = CONFIG_LINE_APPEND;
+        } else if (k[0] == '/') {
+          char *k_new = tor_strdup(k+1);
+          tor_free(k);
+          k = k_new;
+          tor_free(v);
+          v = tor_strdup("");
+          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);
+    } else {
+      tor_free(k);
+      tor_free(v);
+    }
+  } while (*string);
+
+  *result = list;
+  return 0;
+}
+
+/**
+ * Free all the configuration lines on the linked list <b>front</b>.
+ */
+void
+config_free_lines(config_line_t *front)
+{
+  config_line_t *tmp;
+
+  while (front) {
+    tmp = front;
+    front = tmp->next;
+
+    tor_free(tmp->key);
+    tor_free(tmp->value);
+    tor_free(tmp);
+  }
+}
+
+/** As config_find_option, but return a non-const pointer. */
+config_var_t *
+config_find_option_mutable(config_format_t *fmt, const char *key)
+{
+  int i;
+  size_t keylen = strlen(key);
+  if (!keylen)
+    return NULL; /* if they say "--" on the command line, it's not an option */
+  /* First, check for an exact (case-insensitive) match */
+  for (i=0; fmt->vars[i].name; ++i) {
+    if (!strcasecmp(key, fmt->vars[i].name)) {
+      return &fmt->vars[i];
+    }
+  }
+  /* If none, check for an abbreviated match */
+  for (i=0; fmt->vars[i].name; ++i) {
+    if (!strncasecmp(key, fmt->vars[i].name, keylen)) {
+      log_warn(LD_CONFIG, "The abbreviation '%s' is deprecated. "
+               "Please use '%s' instead",
+               key, fmt->vars[i].name);
+      return &fmt->vars[i];
+    }
+  }
+  /* Okay, unrecognized option */
+  return NULL;
+}
+
+/** If <b>key</b> is a configuration option, return the corresponding const
+ * config_var_t.  Otherwise, if <b>key</b> is a non-standard abbreviation,
+ * warn, and return the corresponding const config_var_t.  Otherwise return
+ * NULL.
+ */
+const config_var_t *
+config_find_option(const config_format_t *fmt, const char *key)
+{
+  return config_find_option_mutable((config_format_t*)fmt, key);
+}
+
+/** Return the number of option entries in <b>fmt</b>. */
+static int
+config_count_options(const config_format_t *fmt)
+{
+  int i;
+  for (i=0; fmt->vars[i].name; ++i)
+    ;
+  return i;
+}
+
+/*
+ * Functions to assign config options.
+ */
+
+/** <b>c</b>-\>key is known to be a real key. Update <b>options</b>
+ * with <b>c</b>-\>value and return 0, or return -1 if bad value.
+ *
+ * Called from config_assign_line() and option_reset().
+ */
+static int
+config_assign_value(const config_format_t *fmt, or_options_t *options,
+                    config_line_t *c, char **msg)
+{
+  int i, ok;
+  const config_var_t *var;
+  void *lvalue;
+
+  CONFIG_CHECK(fmt, options);
+
+  var = config_find_option(fmt, c->key);
+  tor_assert(var);
+
+  lvalue = STRUCT_VAR_P(options, var->var_offset);
+
+  switch (var->type) {
+
+  case CONFIG_TYPE_PORT:
+    if (!strcasecmp(c->value, "auto")) {
+      *(int *)lvalue = CFG_AUTO_PORT;
+      break;
+    }
+    /* fall through */
+  case CONFIG_TYPE_INT:
+  case CONFIG_TYPE_UINT:
+    i = (int)tor_parse_long(c->value, 10,
+                            var->type==CONFIG_TYPE_INT ? INT_MIN : 0,
+                            var->type==CONFIG_TYPE_PORT ? 65535 : INT_MAX,
+                            &ok, NULL);
+    if (!ok) {
+      tor_asprintf(msg,
+          "Int keyword '%s %s' is malformed or out of bounds.",
+          c->key, c->value);
+      return -1;
+    }
+    *(int *)lvalue = i;
+    break;
+
+  case CONFIG_TYPE_INTERVAL: {
+    i = config_parse_interval(c->value, &ok);
+    if (!ok) {
+      tor_asprintf(msg,
+          "Interval '%s %s' is malformed or out of bounds.",
+          c->key, c->value);
+      return -1;
+    }
+    *(int *)lvalue = i;
+    break;
+  }
+
+  case CONFIG_TYPE_MSEC_INTERVAL: {
+    i = config_parse_msec_interval(c->value, &ok);
+    if (!ok) {
+      tor_asprintf(msg,
+          "Msec interval '%s %s' is malformed or out of bounds.",
+          c->key, c->value);
+      return -1;
+    }
+    *(int *)lvalue = i;
+    break;
+  }
+
+  case CONFIG_TYPE_MEMUNIT: {
+    uint64_t u64 = config_parse_memunit(c->value, &ok);
+    if (!ok) {
+      tor_asprintf(msg,
+          "Value '%s %s' is malformed or out of bounds.",
+          c->key, c->value);
+      return -1;
+    }
+    *(uint64_t *)lvalue = u64;
+    break;
+  }
+
+  case CONFIG_TYPE_BOOL:
+    i = (int)tor_parse_long(c->value, 10, 0, 1, &ok, NULL);
+    if (!ok) {
+      tor_asprintf(msg,
+          "Boolean '%s %s' expects 0 or 1.",
+          c->key, c->value);
+      return -1;
+    }
+    *(int *)lvalue = i;
+    break;
+
+  case CONFIG_TYPE_AUTOBOOL:
+    if (!strcmp(c->value, "auto"))
+      *(int *)lvalue = -1;
+    else if (!strcmp(c->value, "0"))
+      *(int *)lvalue = 0;
+    else if (!strcmp(c->value, "1"))
+      *(int *)lvalue = 1;
+    else {
+      tor_asprintf(msg, "Boolean '%s %s' expects 0, 1, or 'auto'.",
+                   c->key, c->value);
+      return -1;
+    }
+    break;
+
+  case CONFIG_TYPE_STRING:
+  case CONFIG_TYPE_FILENAME:
+    tor_free(*(char **)lvalue);
+    *(char **)lvalue = tor_strdup(c->value);
+    break;
+
+  case CONFIG_TYPE_DOUBLE:
+    *(double *)lvalue = atof(c->value);
+    break;
+
+  case CONFIG_TYPE_ISOTIME:
+    if (parse_iso_time(c->value, (time_t *)lvalue)) {
+      tor_asprintf(msg,
+          "Invalid time '%s' for keyword '%s'", c->value, c->key);
+      return -1;
+    }
+    break;
+
+  case CONFIG_TYPE_ROUTERSET:
+    if (*(routerset_t**)lvalue) {
+      routerset_free(*(routerset_t**)lvalue);
+    }
+    *(routerset_t**)lvalue = routerset_new();
+    if (routerset_parse(*(routerset_t**)lvalue, c->value, c->key)<0) {
+      tor_asprintf(msg, "Invalid exit list '%s' for option '%s'",
+                   c->value, c->key);
+      return -1;
+    }
+    break;
+
+  case CONFIG_TYPE_CSV:
+    if (*(smartlist_t**)lvalue) {
+      SMARTLIST_FOREACH(*(smartlist_t**)lvalue, char *, cp, tor_free(cp));
+      smartlist_clear(*(smartlist_t**)lvalue);
+    } else {
+      *(smartlist_t**)lvalue = smartlist_new();
+    }
+
+    smartlist_split_string(*(smartlist_t**)lvalue, c->value, ",",
+                           SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
+    break;
+
+  case CONFIG_TYPE_LINELIST:
+  case CONFIG_TYPE_LINELIST_S:
+    {
+      config_line_t *lastval = *(config_line_t**)lvalue;
+      if (lastval && lastval->fragile) {
+        if (c->command != CONFIG_LINE_APPEND) {
+          config_free_lines(lastval);
+          *(config_line_t**)lvalue = NULL;
+        } else {
+          lastval->fragile = 0;
+        }
+      }
+
+      config_line_append((config_line_t**)lvalue, c->key, c->value);
+    }
+    break;
+  case CONFIG_TYPE_OBSOLETE:
+    log_warn(LD_CONFIG, "Skipping obsolete configuration option '%s'", c->key);
+    break;
+  case CONFIG_TYPE_LINELIST_V:
+    tor_asprintf(msg,
+        "You may not provide a value for virtual option '%s'", c->key);
+    return -1;
+  default:
+    tor_assert(0);
+    break;
+  }
+  return 0;
+}
+
+/** Mark every linelist in <b>options</b> "fragile", so that fresh assignments
+ * to it will replace old ones. */
+static void
+config_mark_lists_fragile(const config_format_t *fmt, or_options_t *options)
+{
+  int i;
+  tor_assert(fmt);
+  tor_assert(options);
+
+  for (i = 0; fmt->vars[i].name; ++i) {
+    const config_var_t *var = &fmt->vars[i];
+    config_line_t *list;
+    if (var->type != CONFIG_TYPE_LINELIST &&
+        var->type != CONFIG_TYPE_LINELIST_V)
+      continue;
+
+    list = *(config_line_t **)STRUCT_VAR_P(options, var->var_offset);
+    if (list)
+      list->fragile = 1;
+  }
+}
+
+/** If <b>c</b> is a syntactically valid configuration line, update
+ * <b>options</b> with its value and return 0.  Otherwise return -1 for bad
+ * key, -2 for bad value.
+ *
+ * If <b>clear_first</b> is set, clear the value first. Then if
+ * <b>use_defaults</b> is set, set the value to the default.
+ *
+ * Called from config_assign().
+ */
+static int
+config_assign_line(const config_format_t *fmt, or_options_t *options,
+                   config_line_t *c, int use_defaults,
+                   int clear_first, bitarray_t *options_seen, char **msg)
+{
+  const config_var_t *var;
+
+  CONFIG_CHECK(fmt, options);
+
+  var = config_find_option(fmt, c->key);
+  if (!var) {
+    if (fmt->extra) {
+      void *lvalue = STRUCT_VAR_P(options, fmt->extra->var_offset);
+      log_info(LD_CONFIG,
+               "Found unrecognized option '%s'; saving it.", c->key);
+      config_line_append((config_line_t**)lvalue, c->key, c->value);
+      return 0;
+    } else {
+      tor_asprintf(msg,
+                "Unknown option '%s'.  Failing.", c->key);
+      return -1;
+    }
+  }
+
+  /* Put keyword into canonical case. */
+  if (strcmp(var->name, c->key)) {
+    tor_free(c->key);
+    c->key = tor_strdup(var->name);
+  }
+
+  if (!strlen(c->value)) {
+    /* reset or clear it, then return */
+    if (!clear_first) {
+      if ((var->type == CONFIG_TYPE_LINELIST ||
+           var->type == CONFIG_TYPE_LINELIST_S) &&
+          c->command != CONFIG_LINE_CLEAR) {
+        /* We got an empty linelist from the torrc or command line.
+           As a special case, call this an error. Warn and ignore. */
+        log_warn(LD_CONFIG,
+                 "Linelist option '%s' has no value. Skipping.", c->key);
+      } else { /* not already cleared */
+        config_reset(fmt, options, var, use_defaults);
+      }
+    }
+    return 0;
+  } else if (c->command == CONFIG_LINE_CLEAR && !clear_first) {
+    config_reset(fmt, options, var, use_defaults);
+  }
+
+  if (options_seen && (var->type != CONFIG_TYPE_LINELIST &&
+                       var->type != CONFIG_TYPE_LINELIST_S)) {
+    /* We're tracking which options we've seen, and this option is not
+     * supposed to occur more than once. */
+    int var_index = (int)(var - fmt->vars);
+    if (bitarray_is_set(options_seen, var_index)) {
+      log_warn(LD_CONFIG, "Option '%s' used more than once; all but the last "
+               "value will be ignored.", var->name);
+    }
+    bitarray_set(options_seen, var_index);
+  }
+
+  if (config_assign_value(fmt, options, c, msg) < 0)
+    return -2;
+  return 0;
+}
+
+/** Restore the option named <b>key</b> in options to its default value.
+ * Called from config_assign(). */
+static void
+config_reset_line(const config_format_t *fmt, or_options_t *options,
+                  const char *key, int use_defaults)
+{
+  const config_var_t *var;
+
+  CONFIG_CHECK(fmt, options);
+
+  var = config_find_option(fmt, key);
+  if (!var)
+    return; /* give error on next pass. */
+
+  config_reset(fmt, options, var, use_defaults);
+}
+
+/** Return true iff value needs to be quoted and escaped to be used in
+ * a configuration file. */
+static int
+config_value_needs_escape(const char *value)
+{
+  if (*value == '\"')
+    return 1;
+  while (*value) {
+    switch (*value)
+    {
+    case '\r':
+    case '\n':
+    case '#':
+      /* Note: quotes and backspaces need special handling when we are using
+       * quotes, not otherwise, so they don't trigger escaping on their
+       * own. */
+      return 1;
+    default:
+      if (!TOR_ISPRINT(*value))
+        return 1;
+    }
+    ++value;
+  }
+  return 0;
+}
+
+/** Return a newly allocated deep copy of the lines in <b>inp</b>. */
+config_line_t *
+config_lines_dup(const config_line_t *inp)
+{
+  config_line_t *result = NULL;
+  config_line_t **next_out = &result;
+  while (inp) {
+    *next_out = tor_malloc_zero(sizeof(config_line_t));
+    (*next_out)->key = tor_strdup(inp->key);
+    (*next_out)->value = tor_strdup(inp->value);
+    inp = inp->next;
+    next_out = &((*next_out)->next);
+  }
+  (*next_out) = NULL;
+  return result;
+}
+
+/** Return newly allocated line or lines corresponding to <b>key</b> in the
+ * configuration <b>options</b>.  If <b>escape_val</b> is true and a
+ * value needs to be quoted before it's put in a config file, quote and
+ * escape that value. Return NULL if no such key exists. */
+config_line_t *
+config_get_assigned_option(const config_format_t *fmt, const void *options,
+                             const char *key, int escape_val)
+{
+  const config_var_t *var;
+  const void *value;
+  config_line_t *result;
+  tor_assert(options && key);
+
+  CONFIG_CHECK(fmt, options);
+
+  var = config_find_option(fmt, key);
+  if (!var) {
+    log_warn(LD_CONFIG, "Unknown option '%s'.  Failing.", key);
+    return NULL;
+  }
+  value = STRUCT_VAR_P(options, var->var_offset);
+
+  result = tor_malloc_zero(sizeof(config_line_t));
+  result->key = tor_strdup(var->name);
+  switch (var->type)
+    {
+    case CONFIG_TYPE_STRING:
+    case CONFIG_TYPE_FILENAME:
+      if (*(char**)value) {
+        result->value = tor_strdup(*(char**)value);
+      } else {
+        tor_free(result->key);
+        tor_free(result);
+        return NULL;
+      }
+      break;
+    case CONFIG_TYPE_ISOTIME:
+      if (*(time_t*)value) {
+        result->value = tor_malloc(ISO_TIME_LEN+1);
+        format_iso_time(result->value, *(time_t*)value);
+      } else {
+        tor_free(result->key);
+        tor_free(result);
+      }
+      escape_val = 0; /* Can't need escape. */
+      break;
+    case CONFIG_TYPE_PORT:
+      if (*(int*)value == CFG_AUTO_PORT) {
+        result->value = tor_strdup("auto");
+        escape_val = 0;
+        break;
+      }
+      /* fall through */
+    case CONFIG_TYPE_INTERVAL:
+    case CONFIG_TYPE_MSEC_INTERVAL:
+    case CONFIG_TYPE_UINT:
+    case CONFIG_TYPE_INT:
+      /* This means every or_options_t uint or bool element
+       * needs to be an int. Not, say, a uint16_t or char. */
+      tor_asprintf(&result->value, "%d", *(int*)value);
+      escape_val = 0; /* Can't need escape. */
+      break;
+    case CONFIG_TYPE_MEMUNIT:
+      tor_asprintf(&result->value, U64_FORMAT,
+                   U64_PRINTF_ARG(*(uint64_t*)value));
+      escape_val = 0; /* Can't need escape. */
+      break;
+    case CONFIG_TYPE_DOUBLE:
+      tor_asprintf(&result->value, "%f", *(double*)value);
+      escape_val = 0; /* Can't need escape. */
+      break;
+
+    case CONFIG_TYPE_AUTOBOOL:
+      if (*(int*)value == -1) {
+        result->value = tor_strdup("auto");
+        escape_val = 0;
+        break;
+      }
+      /* fall through */
+    case CONFIG_TYPE_BOOL:
+      result->value = tor_strdup(*(int*)value ? "1" : "0");
+      escape_val = 0; /* Can't need escape. */
+      break;
+    case CONFIG_TYPE_ROUTERSET:
+      result->value = routerset_to_string(*(routerset_t**)value);
+      break;
+    case CONFIG_TYPE_CSV:
+      if (*(smartlist_t**)value)
+        result->value =
+          smartlist_join_strings(*(smartlist_t**)value, ",", 0, NULL);
+      else
+        result->value = tor_strdup("");
+      break;
+    case CONFIG_TYPE_OBSOLETE:
+      log_fn(LOG_INFO, LD_CONFIG,
+             "You asked me for the value of an obsolete config option '%s'.",
+             key);
+      tor_free(result->key);
+      tor_free(result);
+      return NULL;
+    case CONFIG_TYPE_LINELIST_S:
+      log_warn(LD_CONFIG,
+               "Can't return context-sensitive '%s' on its own", key);
+      tor_free(result->key);
+      tor_free(result);
+      return NULL;
+    case CONFIG_TYPE_LINELIST:
+    case CONFIG_TYPE_LINELIST_V:
+      tor_free(result->key);
+      tor_free(result);
+      result = config_lines_dup(*(const config_line_t**)value);
+      break;
+    default:
+      tor_free(result->key);
+      tor_free(result);
+      log_warn(LD_BUG,"Unknown type %d for known key '%s'",
+               var->type, key);
+      return NULL;
+    }
+
+  if (escape_val) {
+    config_line_t *line;
+    for (line = result; line; line = line->next) {
+      if (line->value && config_value_needs_escape(line->value)) {
+        char *newval = esc_for_log(line->value);
+        tor_free(line->value);
+        line->value = newval;
+      }
+    }
+  }
+
+  return result;
+}
+/** Iterate through the linked list of requested options <b>list</b>.
+ * For each item, convert as appropriate and assign to <b>options</b>.
+ * If an item is unrecognized, set *msg and return -1 immediately,
+ * else return 0 for success.
+ *
+ * If <b>clear_first</b>, interpret config options as replacing (not
+ * extending) their previous values. If <b>clear_first</b> is set,
+ * then <b>use_defaults</b> to decide if you set to defaults after
+ * clearing, or make the value 0 or NULL.
+ *
+ * Here are the use cases:
+ * 1. A non-empty AllowInvalid line in your torrc. Appends to current
+ *    if linelist, replaces current if csv.
+ * 2. An empty AllowInvalid line in your torrc. Should clear it.
+ * 3. "RESETCONF AllowInvalid" sets it to default.
+ * 4. "SETCONF AllowInvalid" makes it NULL.
+ * 5. "SETCONF AllowInvalid=foo" clears it and sets it to "foo".
+ *
+ * Use_defaults   Clear_first
+ *    0                0       "append"
+ *    1                0       undefined, don't use
+ *    0                1       "set to null first"
+ *    1                1       "set to defaults first"
+ * Return 0 on success, -1 on bad key, -2 on bad value.
+ *
+ * As an additional special case, if a LINELIST config option has
+ * no value and clear_first is 0, then warn and ignore it.
+ */
+
+/*
+There are three call cases for config_assign() currently.
+
+Case one: Torrc entry
+options_init_from_torrc() calls config_assign(0, 0)
+  calls config_assign_line(0, 0).
+    if value is empty, calls config_reset(0) and returns.
+    calls config_assign_value(), appends.
+
+Case two: setconf
+options_trial_assign() calls config_assign(0, 1)
+  calls config_reset_line(0)
+    calls config_reset(0)
+      calls option_clear().
+  calls config_assign_line(0, 1).
+    if value is empty, returns.
+    calls config_assign_value(), appends.
+
+Case three: resetconf
+options_trial_assign() calls config_assign(1, 1)
+  calls config_reset_line(1)
+    calls config_reset(1)
+      calls option_clear().
+      calls config_assign_value(default)
+  calls config_assign_line(1, 1).
+    returns.
+*/
+int
+config_assign(const config_format_t *fmt, void *options, config_line_t *list,
+              int use_defaults, int clear_first, char **msg)
+{
+  config_line_t *p;
+  bitarray_t *options_seen;
+  const int n_options = config_count_options(fmt);
+
+  CONFIG_CHECK(fmt, options);
+
+  /* pass 1: normalize keys */
+  for (p = list; p; p = p->next) {
+    const char *full = config_expand_abbrev(fmt, p->key, 0, 1);
+    if (strcmp(full,p->key)) {
+      tor_free(p->key);
+      p->key = tor_strdup(full);
+    }
+  }
+
+  /* pass 2: if we're reading from a resetting source, clear all
+   * mentioned config options, and maybe set to their defaults. */
+  if (clear_first) {
+    for (p = list; p; p = p->next)
+      config_reset_line(fmt, options, p->key, use_defaults);
+  }
+
+  options_seen = bitarray_init_zero(n_options);
+  /* pass 3: assign. */
+  while (list) {
+    int r;
+    if ((r=config_assign_line(fmt, options, list, use_defaults,
+                              clear_first, options_seen, msg))) {
+      bitarray_free(options_seen);
+      return r;
+    }
+    list = list->next;
+  }
+  bitarray_free(options_seen);
+
+  /** Now we're done assigning a group of options to the configuration.
+   * Subsequent group assignments should _replace_ linelists, not extend
+   * them. */
+  config_mark_lists_fragile(fmt, options);
+
+  return 0;
+}
+
+/** Reset config option <b>var</b> to 0, 0.0, NULL, or the equivalent.
+ * Called from config_reset() and config_free(). */
+static void
+config_clear(const config_format_t *fmt, void *options,
+             const config_var_t *var)
+{
+  void *lvalue = STRUCT_VAR_P(options, var->var_offset);
+  (void)fmt; /* unused */
+  switch (var->type) {
+    case CONFIG_TYPE_STRING:
+    case CONFIG_TYPE_FILENAME:
+      tor_free(*(char**)lvalue);
+      break;
+    case CONFIG_TYPE_DOUBLE:
+      *(double*)lvalue = 0.0;
+      break;
+    case CONFIG_TYPE_ISOTIME:
+      *(time_t*)lvalue = 0;
+      break;
+    case CONFIG_TYPE_INTERVAL:
+    case CONFIG_TYPE_MSEC_INTERVAL:
+    case CONFIG_TYPE_UINT:
+    case CONFIG_TYPE_INT:
+    case CONFIG_TYPE_PORT:
+    case CONFIG_TYPE_BOOL:
+      *(int*)lvalue = 0;
+      break;
+    case CONFIG_TYPE_AUTOBOOL:
+      *(int*)lvalue = -1;
+      break;
+    case CONFIG_TYPE_MEMUNIT:
+      *(uint64_t*)lvalue = 0;
+      break;
+    case CONFIG_TYPE_ROUTERSET:
+      if (*(routerset_t**)lvalue) {
+        routerset_free(*(routerset_t**)lvalue);
+        *(routerset_t**)lvalue = NULL;
+      }
+      break;
+    case CONFIG_TYPE_CSV:
+      if (*(smartlist_t**)lvalue) {
+        SMARTLIST_FOREACH(*(smartlist_t **)lvalue, char *, cp, tor_free(cp));
+        smartlist_free(*(smartlist_t **)lvalue);
+        *(smartlist_t **)lvalue = NULL;
+      }
+      break;
+    case CONFIG_TYPE_LINELIST:
+    case CONFIG_TYPE_LINELIST_S:
+      config_free_lines(*(config_line_t **)lvalue);
+      *(config_line_t **)lvalue = NULL;
+      break;
+    case CONFIG_TYPE_LINELIST_V:
+      /* handled by linelist_s. */
+      break;
+    case CONFIG_TYPE_OBSOLETE:
+      break;
+  }
+}
+
+/** Clear the option indexed by <b>var</b> in <b>options</b>. Then if
+ * <b>use_defaults</b>, set it to its default value.
+ * Called by config_init() and option_reset_line() and option_assign_line(). */
+static void
+config_reset(const config_format_t *fmt, void *options,
+             const config_var_t *var, int use_defaults)
+{
+  config_line_t *c;
+  char *msg = NULL;
+  CONFIG_CHECK(fmt, options);
+  config_clear(fmt, options, var); /* clear it first */
+  if (!use_defaults)
+    return; /* all done */
+  if (var->initvalue) {
+    c = tor_malloc_zero(sizeof(config_line_t));
+    c->key = tor_strdup(var->name);
+    c->value = tor_strdup(var->initvalue);
+    if (config_assign_value(fmt, options, c, &msg) < 0) {
+      log_warn(LD_BUG, "Failed to assign default: %s", msg);
+      tor_free(msg); /* if this happens it's a bug */
+    }
+    config_free_lines(c);
+  }
+}
+
+/** Release storage held by <b>options</b>. */
+void
+config_free(const config_format_t *fmt, void *options)
+{
+  int i;
+
+  if (!options)
+    return;
+
+  tor_assert(fmt);
+
+  for (i=0; fmt->vars[i].name; ++i)
+    config_clear(fmt, options, &(fmt->vars[i]));
+  if (fmt->extra) {
+    config_line_t **linep = STRUCT_VAR_P(options, fmt->extra->var_offset);
+    config_free_lines(*linep);
+    *linep = NULL;
+  }
+  tor_free(options);
+}
+
+/** Return true iff a and b contain identical keys and values in identical
+ * order. */
+int
+config_lines_eq(config_line_t *a, config_line_t *b)
+{
+  while (a && b) {
+    if (strcasecmp(a->key, b->key) || strcmp(a->value, b->value))
+      return 0;
+    a = a->next;
+    b = b->next;
+  }
+  if (a || b)
+    return 0;
+  return 1;
+}
+
+/** Return the number of lines in <b>a</b> whose key is <b>key</b>. */
+int
+config_count_key(const config_line_t *a, const char *key)
+{
+  int n = 0;
+  while (a) {
+    if (!strcasecmp(a->key, key)) {
+      ++n;
+    }
+    a = a->next;
+  }
+  return n;
+}
+
+/** Return true iff the option <b>name</b> has the same value in <b>o1</b>
+ * and <b>o2</b>.  Must not be called for LINELIST_S or OBSOLETE options.
+ */
+int
+config_is_same(const config_format_t *fmt,
+               const void *o1, const void *o2,
+               const char *name)
+{
+  config_line_t *c1, *c2;
+  int r = 1;
+  CONFIG_CHECK(fmt, o1);
+  CONFIG_CHECK(fmt, o2);
+
+  c1 = config_get_assigned_option(fmt, o1, name, 0);
+  c2 = config_get_assigned_option(fmt, o2, name, 0);
+  r = config_lines_eq(c1, c2);
+  config_free_lines(c1);
+  config_free_lines(c2);
+  return r;
+}
+
+/** Copy storage held by <b>old</b> into a new or_options_t and return it. */
+void *
+config_dup(const config_format_t *fmt, const void *old)
+{
+  or_options_t *newopts;
+  int i;
+  config_line_t *line;
+
+  newopts = config_new(fmt);
+  for (i=0; fmt->vars[i].name; ++i) {
+    if (fmt->vars[i].type == CONFIG_TYPE_LINELIST_S)
+      continue;
+    if (fmt->vars[i].type == CONFIG_TYPE_OBSOLETE)
+      continue;
+    line = config_get_assigned_option(fmt, old, fmt->vars[i].name, 0);
+    if (line) {
+      char *msg = NULL;
+      if (config_assign(fmt, newopts, line, 0, 0, &msg) < 0) {
+        log_err(LD_BUG, "config_get_assigned_option() generated "
+                "something we couldn't config_assign(): %s", msg);
+        tor_free(msg);
+        tor_assert(0);
+      }
+    }
+    config_free_lines(line);
+  }
+  return newopts;
+}
+/** Set all vars in the configuration object <b>options</b> to their default
+ * values. */
+void
+config_init(const config_format_t *fmt, void *options)
+{
+  int i;
+  const config_var_t *var;
+  CONFIG_CHECK(fmt, options);
+
+  for (i=0; fmt->vars[i].name; ++i) {
+    var = &fmt->vars[i];
+    if (!var->initvalue)
+      continue; /* defaults to NULL or 0 */
+    config_reset(fmt, options, var, 1);
+  }
+}
+
+/** Allocate and return a new string holding the written-out values of the vars
+ * in 'options'.  If 'minimal', do not write out any default-valued vars.
+ * Else, if comment_defaults, write default values as comments.
+ */
+char *
+config_dump(const config_format_t *fmt, const void *default_options,
+            const void *options, int minimal,
+            int comment_defaults)
+{
+  smartlist_t *elements;
+  const or_options_t *defaults = default_options;
+  void *defaults_tmp = NULL;
+  config_line_t *line, *assigned;
+  char *result;
+  int i;
+  char *msg = NULL;
+
+  if (defaults == NULL) {
+    defaults = defaults_tmp = config_new(fmt);
+    config_init(fmt, defaults_tmp);
+  }
+
+  /* XXX use a 1 here so we don't add a new log line while dumping */
+  if (default_options == NULL) {
+    if (fmt->validate_fn(NULL, defaults_tmp, 1, &msg) < 0) {
+      log_err(LD_BUG, "Failed to validate default config.");
+      tor_free(msg);
+      tor_assert(0);
+    }
+  }
+
+  elements = smartlist_new();
+  for (i=0; fmt->vars[i].name; ++i) {
+    int comment_option = 0;
+    if (fmt->vars[i].type == CONFIG_TYPE_OBSOLETE ||
+        fmt->vars[i].type == CONFIG_TYPE_LINELIST_S)
+      continue;
+    /* Don't save 'hidden' control variables. */
+    if (!strcmpstart(fmt->vars[i].name, "__"))
+      continue;
+    if (minimal && config_is_same(fmt, options, defaults, fmt->vars[i].name))
+      continue;
+    else if (comment_defaults &&
+             config_is_same(fmt, options, defaults, fmt->vars[i].name))
+      comment_option = 1;
+
+    line = assigned =
+      config_get_assigned_option(fmt, options, fmt->vars[i].name, 1);
+
+    for (; line; line = line->next) {
+      smartlist_add_asprintf(elements, "%s%s %s\n",
+                   comment_option ? "# " : "",
+                   line->key, line->value);
+    }
+    config_free_lines(assigned);
+  }
+
+  if (fmt->extra) {
+    line = *(config_line_t**)STRUCT_VAR_P(options, fmt->extra->var_offset);
+    for (; line; line = line->next) {
+      smartlist_add_asprintf(elements, "%s %s\n", line->key, line->value);
+    }
+  }
+
+  result = smartlist_join_strings(elements, "", 0, NULL);
+  SMARTLIST_FOREACH(elements, char *, cp, tor_free(cp));
+  smartlist_free(elements);
+  if (defaults_tmp)
+    config_free(fmt, defaults_tmp);
+  return result;
+}
+
+/** Mapping from a unit name to a multiplier for converting that unit into a
+ * base unit.  Used by config_parse_unit. */
+struct unit_table_t {
+  const char *unit; /**< The name of the unit */
+  uint64_t multiplier; /**< How many of the base unit appear in this unit */
+};
+
+/** Table to map the names of memory units to the number of bytes they
+ * contain. */
+static struct unit_table_t memory_units[] = {
+  { "",          1 },
+  { "b",         1<< 0 },
+  { "byte",      1<< 0 },
+  { "bytes",     1<< 0 },
+  { "kb",        1<<10 },
+  { "kbyte",     1<<10 },
+  { "kbytes",    1<<10 },
+  { "kilobyte",  1<<10 },
+  { "kilobytes", 1<<10 },
+  { "m",         1<<20 },
+  { "mb",        1<<20 },
+  { "mbyte",     1<<20 },
+  { "mbytes",    1<<20 },
+  { "megabyte",  1<<20 },
+  { "megabytes", 1<<20 },
+  { "gb",        1<<30 },
+  { "gbyte",     1<<30 },
+  { "gbytes",    1<<30 },
+  { "gigabyte",  1<<30 },
+  { "gigabytes", 1<<30 },
+  { "tb",        U64_LITERAL(1)<<40 },
+  { "terabyte",  U64_LITERAL(1)<<40 },
+  { "terabytes", U64_LITERAL(1)<<40 },
+  { NULL, 0 },
+};
+
+/** Table to map the names of time units to the number of seconds they
+ * contain. */
+static struct unit_table_t time_units[] = {
+  { "",         1 },
+  { "second",   1 },
+  { "seconds",  1 },
+  { "minute",   60 },
+  { "minutes",  60 },
+  { "hour",     60*60 },
+  { "hours",    60*60 },
+  { "day",      24*60*60 },
+  { "days",     24*60*60 },
+  { "week",     7*24*60*60 },
+  { "weeks",    7*24*60*60 },
+  { NULL, 0 },
+};
+
+/** Table to map the names of time units to the number of milliseconds
+ * they contain. */
+static struct unit_table_t time_msec_units[] = {
+  { "",         1 },
+  { "msec",     1 },
+  { "millisecond", 1 },
+  { "milliseconds", 1 },
+  { "second",   1000 },
+  { "seconds",  1000 },
+  { "minute",   60*1000 },
+  { "minutes",  60*1000 },
+  { "hour",     60*60*1000 },
+  { "hours",    60*60*1000 },
+  { "day",      24*60*60*1000 },
+  { "days",     24*60*60*1000 },
+  { "week",     7*24*60*60*1000 },
+  { "weeks",    7*24*60*60*1000 },
+  { NULL, 0 },
+};
+
+/** Parse a string <b>val</b> containing a number, zero or more
+ * spaces, and an optional unit string.  If the unit appears in the
+ * table <b>u</b>, then multiply the number by the unit multiplier.
+ * On success, set *<b>ok</b> to 1 and return this product.
+ * Otherwise, set *<b>ok</b> to 0.
+ */
+static uint64_t
+config_parse_units(const char *val, struct unit_table_t *u, int *ok)
+{
+  uint64_t v = 0;
+  double d = 0;
+  int use_float = 0;
+  char *cp;
+
+  tor_assert(ok);
+
+  v = tor_parse_uint64(val, 10, 0, UINT64_MAX, ok, &cp);
+  if (!*ok || (cp && *cp == '.')) {
+    d = tor_parse_double(val, 0, UINT64_MAX, ok, &cp);
+    if (!*ok)
+      goto done;
+    use_float = 1;
+  }
+
+  if (!cp) {
+    *ok = 1;
+    v = use_float ? DBL_TO_U64(d) :  v;
+    goto done;
+  }
+
+  cp = (char*) eat_whitespace(cp);
+
+  for ( ;u->unit;++u) {
+    if (!strcasecmp(u->unit, cp)) {
+      if (use_float)
+        v = u->multiplier * d;
+      else
+        v *= u->multiplier;
+      *ok = 1;
+      goto done;
+    }
+  }
+  log_warn(LD_CONFIG, "Unknown unit '%s'.", cp);
+  *ok = 0;
+ done:
+
+  if (*ok)
+    return v;
+  else
+    return 0;
+}
+
+/** Parse a string in the format "number unit", where unit is a unit of
+ * information (byte, KB, M, etc).  On success, set *<b>ok</b> to true
+ * and return the number of bytes specified.  Otherwise, set
+ * *<b>ok</b> to false and return 0. */
+static uint64_t
+config_parse_memunit(const char *s, int *ok)
+{
+  uint64_t u = config_parse_units(s, memory_units, ok);
+  return u;
+}
+
+/** Parse a string in the format "number unit", where unit is a unit of
+ * time in milliseconds.  On success, set *<b>ok</b> to true and return
+ * the number of milliseconds in the provided interval.  Otherwise, set
+ * *<b>ok</b> to 0 and return -1. */
+static int
+config_parse_msec_interval(const char *s, int *ok)
+{
+  uint64_t r;
+  r = config_parse_units(s, time_msec_units, ok);
+  if (!ok)
+    return -1;
+  if (r > INT_MAX) {
+    log_warn(LD_CONFIG, "Msec interval '%s' is too long", s);
+    *ok = 0;
+    return -1;
+  }
+  return (int)r;
+}
+
+/** Parse a string in the format "number unit", where unit is a unit of time.
+ * On success, set *<b>ok</b> to true and return the number of seconds in
+ * the provided interval.  Otherwise, set *<b>ok</b> to 0 and return -1.
+ */
+static int
+config_parse_interval(const char *s, int *ok)
+{
+  uint64_t r;
+  r = config_parse_units(s, time_units, ok);
+  if (!ok)
+    return -1;
+  if (r > INT_MAX) {
+    log_warn(LD_CONFIG, "Interval '%s' is too long", s);
+    *ok = 0;
+    return -1;
+  }
+  return (int)r;
+}
+
diff --git a/src/or/confparse.h b/src/or/confparse.h
new file mode 100644
index 000000000..f33208eb5
--- /dev/null
+++ b/src/or/confparse.h
@@ -0,0 +1,132 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2012, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_CONFPARSE_H
+#define TOR_CONFPARSE_H
+
+/** Enumeration of types which option values can take */
+typedef enum config_type_t {
+  CONFIG_TYPE_STRING = 0,   /**< An arbitrary string. */
+  CONFIG_TYPE_FILENAME,     /**< A filename: some prefixes get expanded. */
+  CONFIG_TYPE_UINT,         /**< A non-negative integer less than MAX_INT */
+  CONFIG_TYPE_INT,          /**< Any integer. */
+  CONFIG_TYPE_PORT,         /**< A port from 1...65535, 0 for "not set", or
+                             * "auto".  */
+  CONFIG_TYPE_INTERVAL,     /**< A number of seconds, with optional units*/
+  CONFIG_TYPE_MSEC_INTERVAL,/**< A number of milliseconds, with optional
+                              * units */
+  CONFIG_TYPE_MEMUNIT,      /**< A number of bytes, with optional units*/
+  CONFIG_TYPE_DOUBLE,       /**< A floating-point value */
+  CONFIG_TYPE_BOOL,         /**< A boolean value, expressed as 0 or 1. */
+  CONFIG_TYPE_AUTOBOOL,     /**< A boolean+auto value, expressed 0 for false,
+                             * 1 for true, and -1 for auto  */
+  CONFIG_TYPE_ISOTIME,      /**< An ISO-formatted time relative to GMT. */
+  CONFIG_TYPE_CSV,          /**< A list of strings, separated by commas and
+                              * optional whitespace. */
+  CONFIG_TYPE_LINELIST,     /**< Uninterpreted config lines */
+  CONFIG_TYPE_LINELIST_S,   /**< Uninterpreted, context-sensitive config lines,
+                             * mixed with other keywords. */
+  CONFIG_TYPE_LINELIST_V,   /**< Catch-all "virtual" option to summarize
+                             * context-sensitive config lines when fetching.
+                             */
+  CONFIG_TYPE_ROUTERSET,    /**< A list of router names, addrs, and fps,
+                             * parsed into a routerset_t. */
+  CONFIG_TYPE_OBSOLETE,     /**< Obsolete (ignored) option. */
+} config_type_t;
+
+/** An abbreviation for a configuration option allowed on the command line. */
+typedef struct config_abbrev_t {
+  const char *abbreviated;
+  const char *full;
+  int commandline_only;
+  int warn;
+} config_abbrev_t;
+
+/* Handy macro for declaring "In the config file or on the command line,
+ * you can abbreviate <b>tok</b>s as <b>tok</b>". */
+#define PLURAL(tok) { #tok, #tok "s", 0, 0 }
+
+/** A variable allowed in the configuration file or on the command line. */
+typedef struct config_var_t {
+  const char *name; /**< The full keyword (case insensitive). */
+  config_type_t type; /**< How to interpret the type and turn it into a
+                       * value. */
+  off_t var_offset; /**< Offset of the corresponding member of or_options_t. */
+  const char *initvalue; /**< String (or null) describing initial value. */
+} config_var_t;
+
+/** Represents an English description of a configuration variable; used when
+ * generating configuration file comments. */
+typedef struct config_var_description_t {
+  const char *name;
+  const char *description;
+} config_var_description_t;
+
+/** Type of a callback to validate whether a given configuration is
+ * well-formed and consistent. See options_trial_assign() for documentation
+ * of arguments. */
+typedef int (*validate_fn_t)(void*,void*,int,char**);
+
+/** Information on the keys, value types, key-to-struct-member mappings,
+ * variable descriptions, validation functions, and abbreviations for a
+ * configuration or storage format. */
+typedef struct {
+  size_t size; /**< Size of the struct that everything gets parsed into. */
+  uint32_t magic; /**< Required 'magic value' to make sure we have a struct
+                   * of the right type. */
+  off_t magic_offset; /**< Offset of the magic value within the struct. */
+  config_abbrev_t *abbrevs; /**< List of abbreviations that we expand when
+                             * parsing this format. */
+  config_var_t *vars; /**< List of variables we recognize, their default
+                       * values, and where we stick them in the structure. */
+  validate_fn_t validate_fn; /**< Function to validate config. */
+  /** If present, extra is a LINELIST variable for unrecognized
+   * lines.  Otherwise, unrecognized lines are an error. */
+  config_var_t *extra;
+} config_format_t;
+
+/** Macro: assert that <b>cfg</b> has the right magic field for format
+ * <b>fmt</b>. */
+#define CONFIG_CHECK(fmt, cfg) STMT_BEGIN                               \
+    tor_assert(fmt && cfg);                                             \
+    tor_assert((fmt)->magic ==                                          \
+               *(uint32_t*)STRUCT_VAR_P(cfg,fmt->magic_offset));        \
+  STMT_END
+
+void *config_new(const config_format_t *fmt);
+void config_line_append(config_line_t **lst,
+                        const char *key, const char *val);
+config_line_t *config_lines_dup(const config_line_t *inp);
+void config_free(const config_format_t *fmt, void *options);
+int config_lines_eq(config_line_t *a, config_line_t *b);
+int config_count_key(const config_line_t *a, const char *key);
+config_line_t *config_get_assigned_option(const config_format_t *fmt,
+                                          const void *options, const char *key,
+                                          int escape_val);
+int config_is_same(const config_format_t *fmt,
+                   const void *o1, const void *o2,
+                   const char *name);
+void config_init(const config_format_t *fmt, void *options);
+void *config_dup(const config_format_t *fmt, const void *old);
+char *config_dump(const config_format_t *fmt, const void *default_options,
+                  const void *options, int minimal,
+                  int comment_defaults);
+int config_assign(const config_format_t *fmt, void *options,
+                  config_line_t *list,
+                  int use_defaults, int clear_first, char **msg);
+config_var_t *config_find_option_mutable(config_format_t *fmt,
+                                         const char *key);
+const config_var_t *config_find_option(const config_format_t *fmt,
+                                       const char *key);
+
+int config_get_lines(const char *string, config_line_t **result, int extended);
+void config_free_lines(config_line_t *front);
+const char *config_expand_abbrev(const config_format_t *fmt,
+                                 const char *option,
+                                 int command_line, int warn_obsolete);
+
+#endif
+
diff --git a/src/or/control.c b/src/or/control.c
index 4a0f8d70a..bb893267d 100644
--- a/src/or/control.c
+++ b/src/or/control.c
@@ -16,6 +16,7 @@
 #include "circuitlist.h"
 #include "circuituse.h"
 #include "config.h"
+#include "confparse.h"
 #include "connection.h"
 #include "connection_edge.h"
 #include "connection_or.h"
diff --git a/src/or/dirserv.c b/src/or/dirserv.c
index a8f2fb9de..9ca4c54f7 100644
--- a/src/or/dirserv.c
+++ b/src/or/dirserv.c
@@ -7,6 +7,7 @@
 #include "or.h"
 #include "buffers.h"
 #include "config.h"
+#include "confparse.h"
 #include "connection.h"
 #include "connection_or.h"
 #include "control.h"
diff --git a/src/or/include.am b/src/or/include.am
index 97072dce2..fc41c6d53 100644
--- a/src/or/include.am
+++ b/src/or/include.am
@@ -21,7 +21,8 @@ src_or_libtor_a_SOURCES = \
 	src/or/circuitlist.c				\
 	src/or/circuituse.c				\
 	src/or/command.c				\
-	src/or/config.c				\
+	src/or/config.c					\
+	src/or/confparse.c				\
 	src/or/connection.c				\
 	src/or/connection_edge.c			\
 	src/or/connection_or.c				\
@@ -88,6 +89,7 @@ ORHEADERS = \
 	src/or/circuituse.h				\
 	src/or/command.h				\
 	src/or/config.h					\
+	src/or/confparse.h				\
 	src/or/connection.h				\
 	src/or/connection_edge.h			\
 	src/or/connection_or.h				\
diff --git a/src/test/test_config.c b/src/test/test_config.c
index ff251a24d..d9fcd8b35 100644
--- a/src/test/test_config.c
+++ b/src/test/test_config.c
@@ -6,6 +6,7 @@
 #include "orconfig.h"
 #include "or.h"
 #include "config.h"
+#include "confparse.h"
 #include "connection_edge.h"
 #include "test.h"