path: root/harness/src/plugin.c

#include "plugin.h"
#include "foreign_intf.h"

#include <sys/stat.h>
#include <unistd.h>
#include <ctype.h>
#include <dlfcn.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static void shx(uint8_t *state, uint32_t sz)
{
  uint32_t i = 0;
  while (i < sz) {
    for (int j = 0; j < 16; ++j) {
      if (i < sz) {
        printf("%02x ", (unsigned int)state[i]);
      }
      else {
        printf("   ");
      }
      ++i;
    }

    i -= 16;

    printf("   ");

    for (int j = 0; j < 16; ++j) {
      if (i < sz) {
        if (isprint(state[i]) && !isspace(state[i])) {
          printf("%c", state[i]);
        }
        else {
          printf(".");
        }
      }
      else {
        printf(" ");
      }
      ++i;
    }
    printf("\n");
  }
}

int load_plugin_from_dl_(dlhandle_t dl, plugin_t *plug);

static void lock(plugin_t *plugin) { pthread_mutex_lock(&plugin->lock); };

static void unlock(plugin_t *plugin) { pthread_mutex_unlock(&plugin->lock); };

static int plugin_hot_reload_same_state_action_(plugin_t *plugin, void *ignore)
{
  return plugin_hot_reload_same_state(plugin);
}

void do_request_hot_reload(void *plugv)
{
  plugin_t *plugin = plugv;

  size_t n = plugin->n_requested_actions++;
  if (n < 8) {
    plugin->requested_actions[n].action = plugin_hot_reload_same_state_action_;
    plugin->requested_actions[n].arg_dtor = NULL;
  }
}

static int plugin_do_log(plugin_t *plugin, void *chrs)
{
  char *str = chrs;
  puts(str);
  return 0;
}

void do_request_log(void *plugv, const char *str)
{
  plugin_t *plugin = plugv;

  size_t n = plugin->n_requested_actions++;
  if (n < 8) {
    plugin->requested_actions[n].action = plugin_do_log;
    plugin->requested_actions[n].str_arg = strdup(str);
    plugin->requested_actions[n].arg_dtor = free;
  }
}

static int plugin_do_exit(void *plugv, int ec)
{
  exit(ec);
  return 0;
}

void do_request_exit(void *plugv, int ec)
{
  plugin_t *plugin = plugv;

  size_t n = plugin->n_requested_actions++;
  if (n < 8) {
    plugin->requested_actions[n].action =
        (int (*)(plugin_t *, void *))plugin_do_exit;
    plugin->requested_actions[n].int_arg = ec;
    plugin->requested_actions[n].arg_dtor = NULL;
  }
}

static int load_plugin_from_file_(int argc, char **argv, const char *filename,
                                  plugin_t *plugin)
{
  dlhandle_t lib = dlopen(filename, RTLD_LAZY);
  int ec = 0;

  if (!lib) {
    fprintf(stderr, "Failed to open library: %s: %s\n", filename, dlerror());
    ec = 1;
    goto end;
  }

  printf("Loading file.\n");
  ec = load_plugin_from_dl_(lib, plugin);

  if (ec) {
    goto end;
  }

  strncpy(plugin->filename, filename, sizeof(plugin->filename));
  plugin->argc = argc;
  plugin->argv = argv;

  plugin->foreign_intf.ctx = plugin;
  plugin->foreign_intf.request_hot_reload = do_request_hot_reload;
  plugin->foreign_intf.do_log = do_request_log;
  plugin->foreign_intf.request_exit = do_request_exit;

  plugin->plugin_load(plugin->argc, plugin->argv, &plugin->foreign_intf);
end:
  return ec;
}

static void maybe_run_metaload(int argc, char **argv, plugin_t *plugin)
{
  static char *loaded_plugins[12];
  int i;
  for (i = 0; i < 12 && loaded_plugins[i]; ++i) {
    if (strcmp(loaded_plugins[i], plugin->plugin_name) == 0) {
      return; // Plugin is already loaded
    }
  }
  loaded_plugins[i] = strdup(plugin->plugin_name);

  printf("First time loading %s, running metaload.\n", plugin->plugin_name);
  if (plugin->plugin_metaload) {
    plugin->plugin_metaload(argc, argv);
  }
}

int load_plugin_from_file(int argc, char **argv, const char *filename,
                          plugin_t *plugin)
{
  memset(plugin, 0, sizeof(*plugin));

  pthread_mutexattr_t attr;
  if (pthread_mutexattr_init(&attr)) {
    perror("pthread_mutexattr_init");
    return 1;
  }

  if (pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE)) {
    perror("pthread_mutexattr_settype");
    return 1;
  }

  if (pthread_mutex_init(&plugin->lock, &attr)) {
    pthread_mutexattr_destroy(&attr);
    perror("pthread_mutexattr_init");
    return 1;
  }
  pthread_mutexattr_destroy(&attr);
  int rc = load_plugin_from_file_(argc, argv, filename, plugin);

  if (rc == 0) {
    maybe_run_metaload(argc, argv, plugin);
  }

  return rc;
}

int plugin_hot_reload_same_state(plugin_t *plugin)
{
  char filename_cpy[PATH_MAX];
  strncpy(filename_cpy, plugin->filename, sizeof(filename_cpy));
  return plugin_hot_reload(plugin->argc, plugin->argv, filename_cpy, plugin);
}

int plugin_hot_reload(int argc, char **argv, const char *filepath,
                      plugin_t *plugin)
{
  int ec = 0;
  uint32_t sz = 0;
  uint8_t *marshalled_state = NULL;

  printf("Hot Reloading %s\n", plugin->plugin_name);
  lock(plugin);

  printf("Marshalling state ...\n");
  marshalled_state = plugin->plugin_marshal_state(plugin->state, &sz);

  printf("Calling teardown ...\n");
  plugin->plugin_teardown(plugin->state);

  printf("State Marshalled:\n");
  shx(marshalled_state, sz);

  printf("Unloading old library handle.\n");
  if (dlclose(plugin->library_handle)) {
    printf("Could not close library handle: %s\n", dlerror());
  }

  if ((ec = load_plugin_from_file_(argc, argv, filepath, plugin))) {
    goto fail;
  }

  printf("Loading plugin ...\n");
  plugin->plugin_load(plugin->argc, plugin->argv, &plugin->foreign_intf);
  printf("Hot starting plugin ...\n");
  plugin->state = plugin->plugin_hot_start(marshalled_state, sz);

fail:
  free(marshalled_state);
  unlock(plugin);
  return ec;
}

void plugin_run_requested_actions(plugin_t *plugin)
{
  lock(plugin);
  requested_action_t requested_actions[MAX_QUEUED_ACTIONS];
  size_t n_requested_actions = plugin->n_requested_actions;
  memcpy(&requested_actions, plugin->requested_actions,
         sizeof(requested_actions));
  plugin->n_requested_actions = 0;
  unlock(plugin);

  size_t i;
  for (i = 0; i < n_requested_actions; ++i) {
    requested_actions[i].action(plugin, requested_actions[i].str_arg);
    if (requested_actions[i].arg_dtor) {
      requested_actions[i].arg_dtor(requested_actions[i].ptr_arg);
    }
  }
}

void plugin_cold_start(plugin_t *plugin)
{
  lock(plugin);
  plugin->state = plugin->plugin_cold_start();
  unlock(plugin);
}