Merge remote-tracking branch 'asn2/bug3656'

Conflicts:
	src/common/util.c
	src/common/util.h
	src/or/config.h
	src/or/main.c
	src/test/test_util.c

1 files changed, 1048 insertions, 0 deletions

diff --git a/src/or/transports.c b/src/or/transports.c
new file mode 100644
index 0000000000..3c533ccd95
--- /dev/null
+++ b/src/or/transports.c
@@ -0,0 +1,1048 @@
+/* Copyright (c) 2011, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file transports.c
+ * \brief Pluggable Transports related code.
+ **/
+
+#define PT_PRIVATE
+#include "or.h"
+#include "config.h"
+#include "circuitbuild.h"
+#include "transports.h"
+#include "util.h"
+
+static void set_managed_proxy_environment(char ***envp,
+                                          const managed_proxy_t *mp);
+static INLINE int proxy_configuration_finished(const managed_proxy_t *mp);
+
+static void managed_proxy_destroy(managed_proxy_t *mp);
+
+static void handle_finished_proxy(managed_proxy_t *mp);
+static void configure_proxy(managed_proxy_t *mp);
+
+static void parse_method_error(const char *line, int is_server_method);
+#define parse_server_method_error(l) parse_method_error(l, 1)
+#define parse_client_method_error(l) parse_method_error(l, 0)
+
+static INLINE void free_execve_args(char **arg);
+
+/** Managed proxy protocol strings */
+#define PROTO_ENV_ERROR "ENV-ERROR"
+#define PROTO_NEG_SUCCESS "VERSION"
+#define PROTO_NEG_FAIL "VERSION-ERROR no-version"
+#define PROTO_CMETHOD "CMETHOD"
+#define PROTO_SMETHOD "SMETHOD"
+#define PROTO_CMETHOD_ERROR "CMETHOD-ERROR"
+#define PROTO_SMETHOD_ERROR "SMETHOD-ERROR"
+#define PROTO_CMETHODS_DONE "CMETHODS DONE"
+#define PROTO_SMETHODS_DONE "SMETHODS DONE"
+
+/* The smallest valid managed proxy protocol line that can
+   appear. It's the size of "VERSION 1" */
+#define SMALLEST_MANAGED_LINE_SIZE 9
+
+/** Number of environment variables for managed proxy clients/servers. */
+#define ENVIRON_SIZE_CLIENT 5
+#define ENVIRON_SIZE_SERVER 8
+
+/** The first and only supported - at the moment - configuration
+    protocol version. */
+#define PROTO_VERSION_ONE 1
+
+/** List of unconfigured managed proxies. */
+static smartlist_t *managed_proxy_list = NULL;
+/** Number of still unconfigured proxies. */
+static int unconfigured_proxies_n = 0;
+
+/** "The main idea is:"
+
+    Each managed proxy is represented by a 'managed_proxy_t'.
+    Each managed proxy can support multiple transports.
+    Each managed proxy gets configured through a multistep process.
+
+    'managed_proxy_list' contains all the managed proxies this tor
+    instance is supporting.
+    In the 'managed_proxy_list' there are 'unconfigured_proxies_n'
+    managed proxies that are still unconfigured.
+
+    In every run_scheduled_event() tick, we attempt to launch and then
+    configure the unconfiged managed proxies, using the configuration
+    protocol defined in the 180_pluggable_transport.txt proposal. A
+    managed proxy might need several ticks to get fully configured.
+
+    When a managed proxy is fully configured, we register all its
+    transports to the circuitbuild.c subsystem. At that point the
+    transports are owned by the circuitbuild.c subsystem.
+
+    When a managed proxy fails to follow the 180 configuration
+    protocol, it gets marked as broken and gets destroyed.
+
+    "In a little more technical detail:"
+
+    While we are serially parsing torrc, we store all the transports
+    that a proxy should spawn in its 'transports_to_launch' element.
+
+    When we finish reading the torrc, we spawn the managed proxy and
+    expect {S,C}METHOD lines from its output. We add transports
+    described by METHOD lines to its 'transports' element, as
+    'transport_t' structs.
+
+    When the managed proxy stops spitting METHOD lines (signified by a
+    '{S,C}METHODS DONE' message) we register all the transports
+    collected to the circuitbuild.c subsystem. At this point, the
+    'transport_t's can be transformed into dangling pointers at any
+    point by the circuitbuild.c subsystem, and so we replace all
+    'transport_t's with strings describing the transport names.  We
+    can still go from a transport name to a 'transport_t' using the
+    fact that transport names uniquely identify 'transport_t's.
+
+    "In even more technical detail I shall describe what happens when
+    the SIGHUP bell tolls:"
+
+    We immediately destroy all unconfigured proxies (We shouldn't have
+    unconfigured proxies in the first place, except when SIGHUP rings
+    immediately after tor is launched.).
+
+    We mark all managed proxies and transports to signify that they
+    must be removed if they don't contribute by the new torrc
+    (marked_for_removal).
+    We also mark all managed proxies to signify that they might need
+    to be restarted so that they end up supporting all the transports
+    the new torrc wants them to support (got_hup).
+    We also clear their 'transports_to_launch' list so that we can put
+    there the transports we need to launch according to the new torrc.
+
+    We then start parsing torrc again.
+
+    Everytime we encounter a transport line using a known pre-SIGHUP
+    managed proxy, we cleanse that proxy from the removal mark.
+
+    We also mark it as unconfigured so that on the next scheduled
+    events tick, we investigate whether we need to restart the proxy
+    so that it also spawns the new transports.
+    If the post-SIGHUP 'transports_to_launch' list is identical to the
+    pre-SIGHUP one, it means that no changes were introduced to this
+    proxy during the SIGHUP and no restart has to take place.
+
+    During the post-SIGHUP torrc parsing, we unmark all transports
+    spawned by managed proxies that we find in our torrc.
+    We do that so that if we don't need to restart a managed proxy, we
+    can continue using its old transports normally.
+    If we end up restarting the proxy, we destroy and unregister all
+    old transports from the circuitbuild.c subsystem.
+*/
+
+/** Return true if there are still unconfigured managed proxies. */
+int
+pt_proxies_configuration_pending(void)
+{
+  return !! unconfigured_proxies_n;
+}
+
+/** Return true if <b>mp</b> has the same argv as <b>proxy_argv</b> */
+static int
+managed_proxy_has_argv(const managed_proxy_t *mp, char **proxy_argv)
+{
+  char **tmp1=proxy_argv;
+  char **tmp2=mp->argv;
+
+  tor_assert(tmp1);
+  tor_assert(tmp2);
+
+  while (*tmp1 && *tmp2) {
+    if (strcmp(*tmp1++, *tmp2++))
+      return 0;
+  }
+
+  if (!*tmp1 && !*tmp2)
+    return 1;
+
+  return 0;
+}
+
+/** Return a managed proxy with the same argv as <b>proxy_argv</b>.
+ *  If no such managed proxy exists, return NULL. */
+static managed_proxy_t *
+get_managed_proxy_by_argv_and_type(char **proxy_argv, int is_server)
+{
+  if (!managed_proxy_list)
+    return NULL;
+
+  SMARTLIST_FOREACH_BEGIN(managed_proxy_list,  managed_proxy_t *, mp) {
+    if (managed_proxy_has_argv(mp, proxy_argv) &&
+        mp->is_server == is_server)
+      return mp;
+  } SMARTLIST_FOREACH_END(mp);
+
+  return NULL;
+}
+
+/** Add <b>transport</b> to managed proxy <b>mp</b>. */
+static void
+add_transport_to_proxy(const char *transport, managed_proxy_t *mp)
+{
+  tor_assert(mp->transports_to_launch);
+  if (!smartlist_string_isin(mp->transports_to_launch, transport))
+    smartlist_add(mp->transports_to_launch, tor_strdup(transport));
+}
+
+/** Called when a SIGHUP occurs. Returns true if managed proxy
+ *  <b>mp</b> needs to be restarted after the SIGHUP, based on the new
+ *  torrc. */
+static int
+proxy_needs_restart(const managed_proxy_t *mp)
+{
+  /* mp->transport_to_launch is populated with the names of the
+     transports that must be launched *after* the SIGHUP.
+     mp->transports is populated with the names of the transports that
+     were launched *before* the SIGHUP.
+
+     If the two lists contain the same strings, we don't need to
+     restart the proxy, since it already does what we want. */
+
+  tor_assert(smartlist_len(mp->transports_to_launch) > 0);
+  tor_assert(mp->conf_state == PT_PROTO_COMPLETED);
+
+  if (smartlist_len(mp->transports_to_launch) != smartlist_len(mp->transports))
+    goto needs_restart;
+
+  SMARTLIST_FOREACH_BEGIN(mp->transports_to_launch, char *, t_t_l) {
+    if (!smartlist_string_isin(mp->transports, t_t_l))
+      goto needs_restart;
+
+  } SMARTLIST_FOREACH_END(t_t_l);
+
+  return 0;
+
+ needs_restart:
+  return 1;
+}
+
+/** Managed proxy <b>mp</b> must be restarted. Do all the necessary
+ *  preparations and then flag its state so that it will be relaunched
+ *  in the next tick. */
+static void
+proxy_prepare_for_restart(managed_proxy_t *mp)
+{
+  transport_t *t_tmp = NULL;
+
+  tor_assert(mp->conf_state == PT_PROTO_COMPLETED);
+  tor_assert(mp->pid);
+
+  /* kill the old obfsproxy process */
+  tor_terminate_process(mp->pid);
+  mp->pid = 0;
+  fclose(mp->_stdout);
+
+  /* destroy all its old transports. we no longer use them. */
+  SMARTLIST_FOREACH_BEGIN(mp->transports, const char *, t_name) {
+    t_tmp = transport_get_by_name(t_name);
+    if (t_tmp)
+      t_tmp->marked_for_removal = 1;
+  } SMARTLIST_FOREACH_END(t_name);
+  sweep_transport_list();
+
+  /* free the transport names in mp->transports */
+  SMARTLIST_FOREACH(mp->transports, char *, t_name, tor_free(t_name));
+  smartlist_clear(mp->transports);
+
+  /* flag it as an infant proxy so that it gets launched on next tick */
+  mp->conf_state = PT_PROTO_INFANT;
+}
+
+/** Launch managed proxy <b>mp</b>. */
+static int
+launch_managed_proxy(managed_proxy_t *mp)
+{
+  (void) mp;
+  (void) set_managed_proxy_environment;
+  return -1;
+#if 0
+  /* XXXX023 we must reenable this code for managed proxies to work.
+   *   "All it needs" is revision to work with the new tor_spawn_background
+   *   API. */
+  char **envp=NULL;
+  int pid;
+  process_handle_t proc;
+  FILE *stdout_read = NULL;
+  int stdout_pipe=-1, stderr_pipe=-1;
+
+  /* prepare the environment variables for the managed proxy */
+  set_managed_proxy_environment(&envp, mp);
+
+  pid = tor_spawn_background(mp->argv[0], (const char **)mp->argv,
+                             (const char **)envp, &proc);
+  if (pid < 0) {
+    log_warn(LD_GENERAL, "Managed proxy at '%s' failed at launch.",
+             mp->argv[0]);
+    return -1;
+  }
+
+  /* free the memory allocated by set_managed_proxy_environment(). */
+  free_execve_args(envp);
+
+  /* Set stdout/stderr pipes to be non-blocking */
+#ifdef _WIN32
+  {
+    u_long nonblocking = 1;
+    ioctlsocket(stdout_pipe, FIONBIO, &nonblocking);
+  }
+#else
+    fcntl(stdout_pipe, F_SETFL, O_NONBLOCK);
+#endif
+
+  /* Open the buffered IO streams */
+  stdout_read = fdopen(stdout_pipe, "r");
+
+  log_info(LD_CONFIG, "Managed proxy has spawned at PID %d.", pid);
+
+  mp->conf_state = PT_PROTO_LAUNCHED;
+  mp->_stdout = stdout_read;
+  mp->pid = pid;
+#endif
+  return 0;
+}
+
+/** Check if any of the managed proxies we are currently trying to
+ *  configure have anything new to say. This is called from
+ *  run_scheduled_events(). */
+void
+pt_configure_remaining_proxies(void)
+{
+  log_debug(LD_CONFIG, "Configuring remaining managed proxies (%d)!",
+            unconfigured_proxies_n);
+  SMARTLIST_FOREACH_BEGIN(managed_proxy_list,  managed_proxy_t *, mp) {
+    tor_assert(mp->conf_state != PT_PROTO_BROKEN);
+
+    if (mp->got_hup) {
+      mp->got_hup = 0;
+
+    /* This proxy is marked by a SIGHUP. Check whether we need to
+       restart it. */
+      if (proxy_needs_restart(mp)) {
+        log_info(LD_GENERAL, "Preparing managed proxy for restart.");
+        proxy_prepare_for_restart(mp);
+        continue;
+      } else { /* it doesn't need to be restarted. */
+        log_info(LD_GENERAL, "Nothing changed for managed proxy after HUP: "
+                 "not restarting.");
+        unconfigured_proxies_n--;
+        tor_assert(unconfigured_proxies_n >= 0);
+      }
+
+      continue;
+    }
+
+    /* If the proxy is not fully configured, try to configure it
+       futher. */
+    if (!proxy_configuration_finished(mp))
+      configure_proxy(mp);
+
+  } SMARTLIST_FOREACH_END(mp);
+}
+
+/** Attempt to continue configuring managed proxy <b>mp</b>. */
+static void
+configure_proxy(managed_proxy_t *mp)
+{
+  enum stream_status r;
+  char stdout_buf[200];
+
+  /* if we haven't launched the proxy yet, do it now */
+  if (mp->conf_state == PT_PROTO_INFANT) {
+    launch_managed_proxy(mp);
+    return;
+  }
+
+  tor_assert(mp->conf_state != PT_PROTO_INFANT);
+
+  while (1) {
+    r = get_string_from_pipe(mp->_stdout, stdout_buf,
+                             sizeof(stdout_buf) - 1);
+
+    if (r  == IO_STREAM_OKAY) { /* got a line; handle it! */
+      handle_proxy_line((const char *)stdout_buf, mp);
+    } else if (r == IO_STREAM_EAGAIN) { /* check back later */
+      return;
+    } else if (r == IO_STREAM_CLOSED || r == IO_STREAM_TERM) { /* snap! */
+      log_notice(LD_GENERAL, "Managed proxy stream closed. "
+                 "Most probably application stopped running");
+      mp->conf_state = PT_PROTO_BROKEN;
+    } else { /* unknown stream status */
+      log_notice(LD_GENERAL, "Unknown stream status while configuring proxy.");
+    }
+
+    /* if the proxy finished configuring, exit the loop. */
+    if (proxy_configuration_finished(mp)) {
+      handle_finished_proxy(mp);
+      return;
+    }
+  }
+}
+
+/** Register server managed proxy <b>mp</b> transports to state */
+static void
+register_server_proxy(managed_proxy_t *mp)
+{
+  /* After we register this proxy's transports, we switch its
+     mp->transports to a list containing strings of its transport
+     names. (See transports.h) */
+  smartlist_t *sm_tmp = smartlist_create();
+
+  tor_assert(mp->conf_state != PT_PROTO_COMPLETED);
+  SMARTLIST_FOREACH_BEGIN(mp->transports, transport_t *, t) {
+    save_transport_to_state(t->name, &t->addr, t->port);
+    smartlist_add(sm_tmp, tor_strdup(t->name));
+  } SMARTLIST_FOREACH_END(t);
+
+  /* Since server proxies don't register their transports in the
+     circuitbuild.c subsystem, it's our duty to free them when we
+     switch mp->transports to strings. */
+  SMARTLIST_FOREACH(mp->transports, transport_t *, t, transport_free(t));
+  smartlist_free(mp->transports);
+
+  mp->transports = sm_tmp;
+}
+
+/** Register all the transports supported by client managed proxy
+ *  <b>mp</b> to the bridge subsystem. */
+static void
+register_client_proxy(managed_proxy_t *mp)
+{
+  int r;
+  /* After we register this proxy's transports, we switch its
+     mp->transports to a list containing strings of its transport
+     names. (See transports.h) */
+  smartlist_t *sm_tmp = smartlist_create();
+
+  tor_assert(mp->conf_state != PT_PROTO_COMPLETED);
+  SMARTLIST_FOREACH_BEGIN(mp->transports, transport_t *, t) {
+    r = transport_add(t);
+    switch (r) {
+    case -1:
+      log_notice(LD_GENERAL, "Could not add transport %s. Skipping.", t->name);
+      transport_free(t);
+      break;
+    case 0:
+      log_info(LD_GENERAL, "Succesfully registered transport %s", t->name);
+      smartlist_add(sm_tmp, tor_strdup(t->name));
+      break;
+    case 1:
+      log_info(LD_GENERAL, "Succesfully registered transport %s", t->name);
+      smartlist_add(sm_tmp, tor_strdup(t->name));
+      transport_free(t);
+      break;
+    }
+  } SMARTLIST_FOREACH_END(t);
+
+  smartlist_free(mp->transports);
+  mp->transports = sm_tmp;
+}
+
+/** Register the transports of managed proxy <b>mp</b>. */
+static INLINE void
+register_proxy(managed_proxy_t *mp)
+{
+  if (mp->is_server)
+    register_server_proxy(mp);
+  else
+    register_client_proxy(mp);
+}
+
+/** Free memory allocated by managed proxy <b>mp</b>. */
+static void
+managed_proxy_destroy(managed_proxy_t *mp)
+{
+  if (mp->conf_state != PT_PROTO_COMPLETED)
+    SMARTLIST_FOREACH(mp->transports, transport_t *, t, transport_free(t));
+  else
+    SMARTLIST_FOREACH(mp->transports, char *, t_name, tor_free(t_name));
+
+  /* free the transports smartlist */
+  smartlist_free(mp->transports);
+
+  /* free the transports_to_launch smartlist */
+  SMARTLIST_FOREACH(mp->transports_to_launch, char *, t, tor_free(t));
+  smartlist_free(mp->transports_to_launch);
+
+  /* remove it from the list of managed proxies */
+  smartlist_remove(managed_proxy_list, mp);
+
+  /* close its stdout stream */
+  if (mp->_stdout)
+    fclose(mp->_stdout);
+
+  /* free the argv */
+  free_execve_args(mp->argv);
+
+  if (mp->pid)
+    tor_terminate_process(mp->pid);
+
+  tor_free(mp);
+}
+
+/** Handle a configured or broken managed proxy <b>mp</b>. */
+static void
+handle_finished_proxy(managed_proxy_t *mp)
+{
+  switch (mp->conf_state) {
+  case PT_PROTO_BROKEN: /* if broken: */
+    managed_proxy_destroy(mp); /* annihilate it. */
+    break;
+  case PT_PROTO_CONFIGURED: /* if configured correctly: */
+    register_proxy(mp); /* register its transports */
+    mp->conf_state = PT_PROTO_COMPLETED; /* and mark it as completed. */
+    break;
+  case PT_PROTO_INFANT:
+  case PT_PROTO_LAUNCHED:
+  case PT_PROTO_ACCEPTING_METHODS:
+  case PT_PROTO_COMPLETED:
+  default:
+    log_warn(LD_CONFIG, "Unexpected managed proxy state in "
+             "handle_finished_proxy().");
+    tor_assert(0);
+  }
+
+  unconfigured_proxies_n--;
+  tor_assert(unconfigured_proxies_n >= 0);
+}
+
+/** Return true if the configuration of the managed proxy <b>mp</b> is
+    finished. */
+static INLINE int
+proxy_configuration_finished(const managed_proxy_t *mp)
+{
+  return (mp->conf_state == PT_PROTO_CONFIGURED ||
+          mp->conf_state == PT_PROTO_BROKEN);
+}
+
+/** This function is called when a proxy sends an {S,C}METHODS DONE message. */
+static void
+handle_methods_done(const managed_proxy_t *mp)
+{
+  tor_assert(mp->transports);
+
+  if (smartlist_len(mp->transports) == 0)
+    log_notice(LD_GENERAL, "Proxy was spawned successfully, "
+               "but it didn't laucn any pluggable transport listeners!");
+
+  log_info(LD_CONFIG, "%s managed proxy configuration completed!",
+           mp->is_server ? "Server" : "Client");
+}
+
+/** Handle a configuration protocol <b>line</b> received from a
+ *  managed proxy <b>mp</b>. */
+void
+handle_proxy_line(const char *line, managed_proxy_t *mp)
+{
+  log_debug(LD_GENERAL, "Got a line from managed proxy: %s\n", line);
+
+  if (strlen(line) < SMALLEST_MANAGED_LINE_SIZE) {
+    log_warn(LD_GENERAL, "Managed proxy configuration line is too small. "
+             "Discarding");
+    goto err;
+  }
+
+  if (!strcmpstart(line, PROTO_ENV_ERROR)) {
+    if (mp->conf_state != PT_PROTO_LAUNCHED)
+      goto err;
+
+    parse_env_error(line);
+    goto err;
+  } else if (!strcmpstart(line, PROTO_NEG_FAIL)) {
+    if (mp->conf_state != PT_PROTO_LAUNCHED)
+      goto err;
+
+    log_warn(LD_CONFIG, "Managed proxy could not pick a "
+             "configuration protocol version.");
+    goto err;
+  } else if (!strcmpstart(line, PROTO_NEG_SUCCESS)) {
+    if (mp->conf_state != PT_PROTO_LAUNCHED)
+      goto err;
+
+    if (parse_version(line,mp) < 0)
+      goto err;
+
+    tor_assert(mp->conf_protocol != 0);
+    mp->conf_state = PT_PROTO_ACCEPTING_METHODS;
+    return;
+  } else if (!strcmpstart(line, PROTO_CMETHODS_DONE)) {
+    if (mp->conf_state != PT_PROTO_ACCEPTING_METHODS)
+      goto err;
+
+    handle_methods_done(mp);
+
+    mp->conf_state = PT_PROTO_CONFIGURED;
+    return;
+  } else if (!strcmpstart(line, PROTO_SMETHODS_DONE)) {
+    if (mp->conf_state != PT_PROTO_ACCEPTING_METHODS)
+      goto err;
+
+    handle_methods_done(mp);
+
+    mp->conf_state = PT_PROTO_CONFIGURED;
+    return;
+  } else if (!strcmpstart(line, PROTO_CMETHOD_ERROR)) {
+    if (mp->conf_state != PT_PROTO_ACCEPTING_METHODS)
+      goto err;
+
+    parse_client_method_error(line);
+    goto err;
+  } else if (!strcmpstart(line, PROTO_SMETHOD_ERROR)) {
+    if (mp->conf_state != PT_PROTO_ACCEPTING_METHODS)
+      goto err;
+
+    parse_server_method_error(line);
+    goto err;
+  } else if (!strcmpstart(line, PROTO_CMETHOD)) {
+    if (mp->conf_state != PT_PROTO_ACCEPTING_METHODS)
+      goto err;
+
+    if (parse_cmethod_line(line, mp) < 0)
+      goto err;
+
+    return;
+  } else if (!strcmpstart(line, PROTO_SMETHOD)) {
+    if (mp->conf_state != PT_PROTO_ACCEPTING_METHODS)
+      goto err;
+
+    if (parse_smethod_line(line, mp) < 0)
+      goto err;
+
+    return;
+  } else if (!strcmpstart(line, SPAWN_ERROR_MESSAGE)) {
+    log_warn(LD_GENERAL, "Could not launch managed proxy executable!");
+    goto err;
+  }
+
+  log_warn(LD_CONFIG, "Unknown line received by managed proxy. (%s)", line);
+
+ err:
+  mp->conf_state = PT_PROTO_BROKEN;
+  return;
+}
+
+/** Parses an ENV-ERROR <b>line</b> and warns the user accordingly. */
+void
+parse_env_error(const char *line)
+{
+  /* (Length of the protocol string) plus (a space) and (the first char of
+     the error message) */
+  if (strlen(line) < (strlen(PROTO_ENV_ERROR) + 2))
+    log_notice(LD_CONFIG, "Managed proxy sent us an %s without an error "
+               "message.", PROTO_ENV_ERROR);
+
+  log_warn(LD_CONFIG, "Managed proxy couldn't understand the "
+           "pluggable transport environment variables. (%s)",
+           line+strlen(PROTO_ENV_ERROR)+1);
+}
+
+/** Handles a VERSION <b>line</b>. Updates the configuration protocol
+ *  version in <b>mp</b>. */
+int
+parse_version(const char *line, managed_proxy_t *mp)
+{
+  if (strlen(line) < (strlen(PROTO_NEG_SUCCESS) + 2)) {
+    log_warn(LD_CONFIG, "Managed proxy sent us malformed %s line.",
+             PROTO_NEG_SUCCESS);
+    return -1;
+  }
+
+  if (strcmp("1", line+strlen(PROTO_NEG_SUCCESS)+1)) { /* hardcoded temp */
+    log_warn(LD_CONFIG, "Managed proxy tried to negotiate on version '%s'. "
+             "We only support version '1'", line+strlen(PROTO_NEG_SUCCESS)+1);
+    return -1;
+  }
+
+  mp->conf_protocol = PROTO_VERSION_ONE; /* temp. till more versions appear */
+  return 0;
+}
+
+/** Parses {C,S}METHOD-ERROR <b>line</b> and warns the user
+ *  accordingly.  If <b>is_server</b> it is an SMETHOD-ERROR,
+ *  otherwise it is a CMETHOD-ERROR. */
+static void
+parse_method_error(const char *line, int is_server)
+{
+  const char* error = is_server ?
+    PROTO_SMETHOD_ERROR : PROTO_CMETHOD_ERROR;
+
+  /* (Length of the protocol string) plus (a space) and (the first char of
+     the error message) */
+  if (strlen(line) < (strlen(error) + 2))
+    log_warn(LD_CONFIG, "Managed proxy sent us an %s without an error "
+             "message.", error);
+
+  log_warn(LD_CONFIG, "%s managed proxy encountered a method error. (%s)",
+           is_server ? "Server" : "Client",
+           line+strlen(error)+1);
+}
+
+/** Parses an SMETHOD <b>line</b> and if well-formed it registers the
+ *  new transport in <b>mp</b>. */
+int
+parse_smethod_line(const char *line, managed_proxy_t *mp)
+{
+  int r;
+  smartlist_t *items = NULL;
+
+  char *method_name=NULL;
+
+  char *addrport=NULL;
+  tor_addr_t addr;
+  uint16_t port = 0;
+
+  transport_t *transport=NULL;
+
+  items = smartlist_create();
+  smartlist_split_string(items, line, NULL,
+                         SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, -1);
+  if (smartlist_len(items) < 3) {
+    log_warn(LD_CONFIG, "Server managed proxy sent us a SMETHOD line "
+             "with too few arguments.");
+    goto err;
+  }
+
+  tor_assert(!strcmp(smartlist_get(items,0),PROTO_SMETHOD));
+
+  method_name = smartlist_get(items,1);
+  if (!string_is_C_identifier(method_name)) {
+    log_warn(LD_CONFIG, "Transport name is not a C identifier (%s).",
+             method_name);
+    goto err;
+  }
+
+  addrport = smartlist_get(items, 2);
+  if (tor_addr_port_parse(addrport, &addr, &port)<0) {
+    log_warn(LD_CONFIG, "Error parsing transport "
+             "address '%s'", addrport);
+    goto err;
+  }
+
+  if (!port) {
+    log_warn(LD_CONFIG,
+             "Transport address '%s' has no port.", addrport);
+    goto err;
+  }
+
+  transport = transport_create(&addr, port, method_name, PROXY_NONE);
+  if (!transport)
+    goto err;
+
+  smartlist_add(mp->transports, transport);
+
+  /* For now, notify the user so that he knows where the server
+     transport is listening. */
+  log_info(LD_CONFIG, "Server transport %s at %s:%d.",
+           method_name, fmt_addr(&addr), (int)port);
+
+  r=0;
+  goto done;
+
+ err:
+  r = -1;
+
+ done:
+  SMARTLIST_FOREACH(items, char*, s, tor_free(s));
+  smartlist_free(items);
+  return r;
+}
+
+/** Parses a CMETHOD <b>line</b>, and if well-formed it registers
+ *  the new transport in <b>mp</b>. */
+int
+parse_cmethod_line(const char *line, managed_proxy_t *mp)
+{
+  int r;
+  smartlist_t *items = NULL;
+
+  char *method_name=NULL;
+
+  char *socks_ver_str=NULL;
+  int socks_ver=PROXY_NONE;
+
+  char *addrport=NULL;
+  tor_addr_t addr;
+  uint16_t port = 0;
+
+  transport_t *transport=NULL;
+
+  items = smartlist_create();
+  smartlist_split_string(items, line, NULL,
+                         SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, -1);
+  if (smartlist_len(items) < 4) {
+    log_warn(LD_CONFIG, "Client managed proxy sent us a CMETHOD line "
+             "with too few arguments.");
+    goto err;
+  }
+
+  tor_assert(!strcmp(smartlist_get(items,0),PROTO_CMETHOD));
+
+  method_name = smartlist_get(items,1);
+  if (!string_is_C_identifier(method_name)) {
+    log_warn(LD_CONFIG, "Transport name is not a C identifier (%s).",
+             method_name);
+    goto err;
+  }
+
+  socks_ver_str = smartlist_get(items,2);
+
+  if (!strcmp(socks_ver_str,"socks4")) {
+    socks_ver = PROXY_SOCKS4;
+  } else if (!strcmp(socks_ver_str,"socks5")) {
+    socks_ver = PROXY_SOCKS5;
+  } else {
+    log_warn(LD_CONFIG, "Client managed proxy sent us a proxy protocol "
+             "we don't recognize. (%s)", socks_ver_str);
+    goto err;
+  }
+
+  addrport = smartlist_get(items, 3);
+  if (tor_addr_port_parse(addrport, &addr, &port)<0) {
+    log_warn(LD_CONFIG, "Error parsing transport "
+             "address '%s'", addrport);
+    goto err;
+  }
+
+  if (!port) {
+    log_warn(LD_CONFIG,
+             "Transport address '%s' has no port.", addrport);
+    goto err;
+  }
+
+  transport = transport_create(&addr, port, method_name, socks_ver);
+  if (!transport)
+    goto err;
+
+  smartlist_add(mp->transports, transport);
+
+  log_info(LD_CONFIG, "Transport %s at %s:%d with SOCKS %d. "
+           "Attached to managed proxy.",
+           method_name, fmt_addr(&addr), (int)port, socks_ver);
+
+  r=0;
+  goto done;
+
+ err:
+  r = -1;
+
+ done:
+  SMARTLIST_FOREACH(items, char*, s, tor_free(s));
+  smartlist_free(items);
+  return r;
+}
+
+/** Return a string containing the address:port that <b>transport</b>
+ *  should use. It's the responsibility of the caller to free() the
+ *  received string. */
+static char *
+get_bindaddr_for_proxy(const managed_proxy_t *mp)
+{
+  char *bindaddr = NULL;
+  smartlist_t *string_tmp = smartlist_create();
+
+  tor_assert(mp->is_server);
+
+  SMARTLIST_FOREACH_BEGIN(mp->transports_to_launch, char *, t) {
+    tor_asprintf(&bindaddr, "%s-%s", t, get_bindaddr_for_transport(t));
+    smartlist_add(string_tmp, bindaddr);
+  } SMARTLIST_FOREACH_END(t);
+
+  bindaddr = smartlist_join_strings(string_tmp, ",", 0, NULL);
+
+  SMARTLIST_FOREACH(string_tmp, char *, t, tor_free(t));
+  smartlist_free(string_tmp);
+
+  return bindaddr;
+}
+
+/** Prepare the <b>envp</b> of managed proxy <b>mp</b> */
+static void
+set_managed_proxy_environment(char ***envp, const managed_proxy_t *mp)
+{
+  const or_options_t *options = get_options();
+  char **tmp=NULL;
+  char *state_loc=NULL;
+  char *transports_to_launch=NULL;
+  char *bindaddr=NULL;
+
+  int n_envs = mp->is_server ? ENVIRON_SIZE_SERVER : ENVIRON_SIZE_CLIENT;
+
+  /* allocate enough space for our env. vars and a NULL pointer */
+  *envp = tor_malloc(sizeof(char*)*(n_envs+1));
+  tmp = *envp;
+
+  state_loc = get_datadir_fname("pt_state/"); /* XXX temp */
+  transports_to_launch =
+    smartlist_join_strings(mp->transports_to_launch, ",", 0, NULL);
+
+  tor_asprintf(tmp++, "HOME=%s", getenv("HOME"));
+  tor_asprintf(tmp++, "PATH=%s", getenv("PATH"));
+  tor_asprintf(tmp++, "TOR_PT_STATE_LOCATION=%s", state_loc);
+  tor_asprintf(tmp++, "TOR_PT_MANAGED_TRANSPORT_VER=1"); /* temp */
+  if (mp->is_server) {
+    bindaddr = get_bindaddr_for_proxy(mp);
+
+    /* XXX temp */
+    tor_asprintf(tmp++, "TOR_PT_ORPORT=127.0.0.1:%d", options->ORPort);
+    tor_asprintf(tmp++, "TOR_PT_SERVER_BINDADDR=%s", bindaddr);
+    tor_asprintf(tmp++, "TOR_PT_SERVER_TRANSPORTS=%s", transports_to_launch);
+    /* XXX temp*/
+    tor_asprintf(tmp++, "TOR_PT_EXTENDED_SERVER_PORT=127.0.0.1:4200");
+  } else {
+    tor_asprintf(tmp++, "TOR_PT_CLIENT_TRANSPORTS=%s", transports_to_launch);
+  }
+  *tmp = NULL;
+
+  tor_free(state_loc);
+  tor_free(transports_to_launch);
+  tor_free(bindaddr);
+}
+
+/** Create and return a new managed proxy for <b>transport</b> using
+ *  <b>proxy_argv</b>. If <b>is_server</b> is true, it's a server
+ *  managed proxy. */
+static managed_proxy_t *
+managed_proxy_create(const smartlist_t *transport_list,
+                     char **proxy_argv, int is_server)
+{
+  managed_proxy_t *mp = tor_malloc_zero(sizeof(managed_proxy_t));
+  mp->conf_state = PT_PROTO_INFANT;
+  mp->is_server = is_server;
+  mp->argv = proxy_argv;
+  mp->transports = smartlist_create();
+
+  mp->transports_to_launch = smartlist_create();
+  SMARTLIST_FOREACH(transport_list, const char *, transport,
+                    add_transport_to_proxy(transport, mp));
+
+  /* register the managed proxy */
+  if (!managed_proxy_list)
+    managed_proxy_list = smartlist_create();
+  smartlist_add(managed_proxy_list, mp);
+  unconfigured_proxies_n++;
+
+  return mp;
+}
+
+/** Register <b>transport</b> using proxy with <b>proxy_argv</b> to
+ *  the managed proxy subsystem.
+ *  If <b>is_server</b> is true, then the proxy is a server proxy. */
+void
+pt_kickstart_proxy(const smartlist_t *transport_list,
+                   char **proxy_argv, int is_server)
+{
+  managed_proxy_t *mp=NULL;
+  transport_t *old_transport = NULL;
+
+  mp = get_managed_proxy_by_argv_and_type(proxy_argv, is_server);
+
+  if (!mp) { /* we haven't seen this proxy before */
+    managed_proxy_create(transport_list, proxy_argv, is_server);
+
+  } else { /* known proxy. add its transport to its transport list */
+    if (mp->got_hup) {
+      /* If the managed proxy we found is marked by a SIGHUP, it means
+         that it's not useless and should be kept. If it's marked for
+         removal, unmark it and increase the unconfigured proxies so
+         that we try to restart it if we need to. Afterwards, check if
+         a transport_t for 'transport' used to exist before the SIGHUP
+         and make sure it doesn't get deleted because we might reuse
+         it. */
+      if (mp->marked_for_removal) {
+        mp->marked_for_removal = 0;
+        unconfigured_proxies_n++;
+      }
+
+      SMARTLIST_FOREACH_BEGIN(transport_list, const char *, transport) {
+        old_transport = transport_get_by_name(transport);
+        if (old_transport)
+          old_transport->marked_for_removal = 0;
+      } SMARTLIST_FOREACH_END(transport);
+    }
+
+    SMARTLIST_FOREACH(transport_list, const char *, transport,
+                      add_transport_to_proxy(transport, mp));
+    free_execve_args(proxy_argv);
+  }
+}
+
+/** Frees the array of pointers in <b>arg</b> used as arguments to
+    execve(2). */
+static INLINE void
+free_execve_args(char **arg)
+{
+  char **tmp = arg;
+  while (*tmp) /* use the fact that the last element of the array is a
+                  NULL pointer to know when to stop freeing */
+    _tor_free(*tmp++);
+
+  tor_free(arg);
+}
+
+/** Tor will read its config.
+ *  Prepare the managed proxy list so that proxies not used in the new
+ *  config will shutdown, and proxies that need to spawn different
+ *  transports will do so. */
+void
+pt_prepare_proxy_list_for_config_read(void)
+{
+  if (!managed_proxy_list)
+    return;
+
+  SMARTLIST_FOREACH_BEGIN(managed_proxy_list, managed_proxy_t *, mp) {
+    /* Destroy unconfigured proxies. */
+    if (mp->conf_state != PT_PROTO_COMPLETED) {
+        managed_proxy_destroy(mp);
+        unconfigured_proxies_n--;
+        continue;
+    }
+
+    tor_assert(mp->conf_state == PT_PROTO_COMPLETED);
+
+    mp->marked_for_removal = 1;
+    mp->got_hup = 1;
+    SMARTLIST_FOREACH(mp->transports_to_launch, char *, t, tor_free(t));
+    smartlist_clear(mp->transports_to_launch);
+  } SMARTLIST_FOREACH_END(mp);
+
+  tor_assert(unconfigured_proxies_n == 0);
+}
+
+/** The tor config was read.
+ *  Destroy all managed proxies that were marked by a previous call to
+ *  prepare_proxy_list_for_config_read() and are not used by the new
+ *  config. */
+void
+sweep_proxy_list(void)
+{
+  if (!managed_proxy_list)
+    return;
+
+  SMARTLIST_FOREACH_BEGIN(managed_proxy_list, managed_proxy_t *, mp) {
+    if (mp->marked_for_removal) {
+      SMARTLIST_DEL_CURRENT(managed_proxy_list, mp);
+      managed_proxy_destroy(mp);
+    }
+  } SMARTLIST_FOREACH_END(mp);
+}
+
+/** Release all storage held by the pluggable transports subsystem. */
+void
+pt_free_all(void)
+{
+  if (managed_proxy_list) {
+    /* If the proxy is in PT_PROTO_COMPLETED, it has registered its
+       transports and it's the duty of the circuitbuild.c subsystem to
+       free them. Otherwise, it hasn't registered its transports yet
+       and we should free them here. */
+    SMARTLIST_FOREACH(managed_proxy_list, managed_proxy_t *, mp,
+                      managed_proxy_destroy(mp));
+
+    smartlist_free(managed_proxy_list);
+    managed_proxy_list=NULL;
+  }
+}
+