/*
 * Copyright 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <errno.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <sys/select.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>
#include <unistd.h>

#include "osi/include/osi.h"
#include "osi/include/socket_utils/socket_local.h"
#include "osi/include/socket_utils/sockets.h"

#define LISTEN_BACKLOG 4

/* Documented in header file. */
int osi_socket_make_sockaddr_un(const char* name, int namespaceId,
                                struct sockaddr_un* p_addr, socklen_t* alen) {
  memset(p_addr, 0, sizeof(*p_addr));
  size_t namelen;

  switch (namespaceId) {
    case ANDROID_SOCKET_NAMESPACE_ABSTRACT:
#if defined(__linux__)
      namelen = strlen(name);

      // Test with length +1 for the *initial* '\0'.
      if ((namelen + 1) > sizeof(p_addr->sun_path)) {
        goto error;
      }

      /*
       * Note: The path in this case is *not* supposed to be
       * '\0'-terminated. ("man 7 unix" for the gory details.)
       */

      p_addr->sun_path[0] = 0;
      memcpy(p_addr->sun_path + 1, name, namelen);
#else
      /* this OS doesn't have the Linux abstract namespace */

      namelen = strlen(name) + strlen(FILESYSTEM_SOCKET_PREFIX);
      /* unix_path_max appears to be missing on linux */
      if (namelen >
          sizeof(*p_addr) - offsetof(struct sockaddr_un, sun_path) - 1) {
        goto error;
      }

      strcpy(p_addr->sun_path, FILESYSTEM_SOCKET_PREFIX);
      strcat(p_addr->sun_path, name);
#endif
      break;

    case ANDROID_SOCKET_NAMESPACE_RESERVED:
      namelen = strlen(name) + strlen(ANDROID_RESERVED_SOCKET_PREFIX);
      /* unix_path_max appears to be missing on linux */
      if (namelen >
          sizeof(*p_addr) - offsetof(struct sockaddr_un, sun_path) - 1) {
        goto error;
      }

      strcpy(p_addr->sun_path, ANDROID_RESERVED_SOCKET_PREFIX);
      strcat(p_addr->sun_path, name);
      break;

    case ANDROID_SOCKET_NAMESPACE_FILESYSTEM:
      namelen = strlen(name);
      /* unix_path_max appears to be missing on linux */
      if (namelen >
          sizeof(*p_addr) - offsetof(struct sockaddr_un, sun_path) - 1) {
        goto error;
      }

      strcpy(p_addr->sun_path, name);
      break;
    default:
      // invalid namespace id
      return -1;
  }

  p_addr->sun_family = AF_LOCAL;
  *alen = namelen + offsetof(struct sockaddr_un, sun_path) + 1;
  return 0;
error:
  return -1;
}

/**
 * connect to peer named "name" on fd
 * returns same fd or -1 on error.
 * fd is not closed on error. that's your job.
 *
 * Used by AndroidSocketImpl
 */
int osi_socket_local_client_connect(int fd, const char* name, int namespaceId,
                                    int type UNUSED_ATTR) {
  struct sockaddr_un addr;
  socklen_t alen;
  int err;

  err = osi_socket_make_sockaddr_un(name, namespaceId, &addr, &alen);

  if (err < 0) {
    goto error;
  }

  OSI_NO_INTR(err = connect(fd, (struct sockaddr*)&addr, alen));
  if (err < 0) {
    goto error;
  }

  return fd;

error:
  return -1;
}

/**
 * connect to peer named "name"
 * returns fd or -1 on error
 */
int osi_socket_local_client(const char* name, int namespaceId, int type) {
  int s;

  s = socket(AF_LOCAL, type, 0);
  if (s < 0) return -1;

  if (0 > osi_socket_local_client_connect(s, name, namespaceId, type)) {
    close(s);
    return -1;
  }

  return s;
}