C++ RESTARTABLE函数代码示例

/*
 * Class:     sun_tools_attach_BSDVirtualMachine
 * Method:    createAttachFile
 * Signature: (Ljava.lang.String;)V
 */
JNIEXPORT void JNICALL Java_sun_tools_attach_BsdVirtualMachine_createAttachFile(JNIEnv *env, jclass cls, jstring path)
{
    const char* _path;
    jboolean isCopy;
    int fd, rc;

    _path = GetStringPlatformChars(env, path, &isCopy);
    if (_path == NULL) {
        JNU_ThrowIOException(env, "Must specify a path");
        return;
    }

    RESTARTABLE(open(_path, O_CREAT | O_EXCL, S_IWUSR | S_IRUSR), fd);
    if (fd == -1) {
        /* release p here before we throw an I/O exception */
        if (isCopy) {
            JNU_ReleaseStringPlatformChars(env, path, _path);
        }
        JNU_ThrowIOExceptionWithLastError(env, "open");
        return;
    }

    RESTARTABLE(chown(_path, geteuid(), getegid()), rc);

    RESTARTABLE(close(fd), rc);

    /* release p here */
    if (isCopy) {
        JNU_ReleaseStringPlatformChars(env, path, _path);
    }
}

// Open the directory of the given path and validate it.
// Return a DIR * of the open directory.
static DIR *open_directory_secure(const char* dirname) {
  // Open the directory using open() so that it can be verified
  // to be secure by calling is_dirfd_secure(), opendir() and then check
  // to see if they are the same file system object.  This method does not
  // introduce a window of opportunity for the directory to be attacked that
  // calling opendir() and is_directory_secure() does.
  int result;
  DIR *dirp = NULL;

  // No O_NOFOLLOW defined at buildtime, and it is not documented for open;
  // so provide a workaround in this case.
#ifdef O_NOFOLLOW
  RESTARTABLE(::open(dirname, O_RDONLY|O_NOFOLLOW), result);
#else
  // workaround (jdk6 coding)
  RESTARTABLE(::open_o_nofollow(dirname, O_RDONLY), result);
#endif

  if (result == OS_ERR) {
    // Directory doesn't exist or is a symlink, so there is nothing to cleanup.
    if (PrintMiscellaneous && Verbose) {
      if (errno == ELOOP) {
        warning("directory %s is a symlink and is not secure\n", dirname);
      } else {
        warning("could not open directory %s: %s\n", dirname, strerror(errno));
      }
    }
    return dirp;
  }
  int fd = result;

  // Determine if the open directory is secure.
  if (!is_dirfd_secure(fd)) {
    // The directory is not a secure directory.
    os::close(fd);
    return dirp;
  }

  // Open the directory.
  dirp = ::opendir(dirname);
  if (dirp == NULL) {
    // The directory doesn't exist, close fd and return.
    os::close(fd);
    return dirp;
  }

  // Check to make sure fd and dirp are referencing the same file system object.
  if (!is_same_fsobject(fd, dirp->dd_fd)) {
    // The directory is not secure.
    os::close(fd);
    os::closedir(dirp);
    dirp = NULL;
    return dirp;
  }

  // Close initial open now that we know directory is secure
  os::close(fd);

  return dirp;
}

/**
 * Converts an existing file descriptor, that references an unbound TCP socket,
 * to SDP.
 */
JNIEXPORT void JNICALL
Java_sun_net_sdp_SdpSupport_convert0(JNIEnv *env, jclass cls, int fd)
{
    int s = create(env);
    if (s >= 0) {
        socklen_t len;
        int arg, res;
        struct linger linger;

        /* copy socket options that are relevant to SDP */
        len = sizeof(arg);
        if (getsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char*)&arg, &len) == 0)
            setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char*)&arg, len);
        len = sizeof(arg);
        if (getsockopt(fd, SOL_SOCKET, SO_OOBINLINE, (char*)&arg, &len) == 0)
            setsockopt(s, SOL_SOCKET, SO_OOBINLINE, (char*)&arg, len);
        len = sizeof(linger);
        if (getsockopt(fd, SOL_SOCKET, SO_LINGER, (void*)&linger, &len) == 0)
            setsockopt(s, SOL_SOCKET, SO_LINGER, (char*)&linger, len);

        RESTARTABLE(dup2(s, fd), res);
        if (res < 0)
            JNU_ThrowIOExceptionWithLastError(env, "dup2");
        RESTARTABLE(close(s), res);
    }
}

int BsdAttachListener::init() {
  char path[UNIX_PATH_MAX];          // socket file
  char initial_path[UNIX_PATH_MAX];  // socket file during setup
  int listener;                      // listener socket (file descriptor)

  // register function to cleanup
  ::atexit(listener_cleanup);

  int n = snprintf(path, UNIX_PATH_MAX, "%s/.java_pid%d",
                   os::get_temp_directory(), os::current_process_id());
  if (n < (int)UNIX_PATH_MAX) {
    n = snprintf(initial_path, UNIX_PATH_MAX, "%s.tmp", path);
  }
  if (n >= (int)UNIX_PATH_MAX) {
    return -1;
  }

  // create the listener socket
  listener = ::socket(PF_UNIX, SOCK_STREAM, 0);
  if (listener == -1) {
    return -1;
  }

  // bind socket
  struct sockaddr_un addr;
  addr.sun_family = AF_UNIX;
  strcpy(addr.sun_path, initial_path);
  ::unlink(initial_path);
  int res = ::bind(listener, (struct sockaddr*)&addr, sizeof(addr));
  if (res == -1) {
    ::close(listener);
    return -1;
  }

  // put in listen mode, set permissions, and rename into place
  res = ::listen(listener, 5);
  if (res == 0) {
    RESTARTABLE(::chmod(initial_path, S_IREAD|S_IWRITE), res);
    if (res == 0) {
      // make sure the file is owned by the effective user and effective group
      // (this is the default on linux, but not on mac os)
      RESTARTABLE(::chown(initial_path, geteuid(), getegid()), res);
      if (res == 0) {
        res = ::rename(initial_path, path);
      }
    }
  }
  if (res == -1) {
    ::close(listener);
    ::unlink(initial_path);
    return -1;
  }
  set_path(path);
  set_listener(listener);

  return 0;
}

// check if the given path is considered a secure directory for
// the backing store files. Returns true if the directory exists
// and is considered a secure location. Returns false if the path
// is a symbolic link or if an error occurred.
//
static bool is_directory_secure(const char* path) {
  struct stat statbuf;
  int result = 0;

  RESTARTABLE(::lstat(path, &statbuf), result);
  if (result == OS_ERR) {
    return false;
  }

  // the path exists, now check it's mode
  if (S_ISLNK(statbuf.st_mode) || !S_ISDIR(statbuf.st_mode)) {
    // the path represents a link or some non-directory file type,
    // which is not what we expected. declare it insecure.
    //
    return false;
  }
  else {
    // we have an existing directory, check if the permissions are safe.
    //
    if ((statbuf.st_mode & (S_IWGRP|S_IWOTH)) != 0) {
      // the directory is open for writing and could be subjected
      // to a symlnk attack. declare it insecure.
      //
      return false;
    }
  }
  return true;
}

/*
 * Class:     sun_tools_attach_LinuxVirtualMachine
 * Method:    write
 * Signature: (I[B)V
 */
JNIEXPORT void JNICALL Java_sun_tools_attach_LinuxVirtualMachine_write
  (JNIEnv *env, jclass cls, jint fd, jbyteArray ba, jint off, jint bufLen)
{
    size_t remaining = bufLen;
    do {
        unsigned char buf[128];
        size_t len = sizeof(buf);
        int n;

        if (len > remaining) {
            len = remaining;
        }
        (*env)->GetByteArrayRegion(env, ba, off, len, (jbyte *)buf);

        RESTARTABLE(write(fd, buf, len), n);
        if (n > 0) {
           off += n;
           remaining -= n;
        } else {
            JNU_ThrowIOExceptionWithLastError(env, "write");
            return;
        }

    } while (remaining > 0);
}

// Create the door
int SolarisAttachListener::create_door() {
  char door_path[PATH_MAX+1];
  char initial_path[PATH_MAX+1];
  int fd, res;

  // register exit function
  ::atexit(listener_cleanup);

  // create the door descriptor
  int dd = ::door_create(enqueue_proc, NULL, 0);
  if (dd < 0) {
    return -1;
  }

  // create initial file to attach door descriptor
  snprintf(door_path, sizeof(door_path), "%s/.java_pid%d",
           os::get_temp_directory(), os::current_process_id());
  snprintf(initial_path, sizeof(initial_path), "%s.tmp", door_path);
  RESTARTABLE(::creat(initial_path, S_IRUSR | S_IWUSR), fd);
  if (fd == -1) {
    debug_only(warning("attempt to create %s failed", initial_path));
    ::door_revoke(dd);
    return -1;
  }
  assert(fd >= 0, "bad file descriptor");
  ::close(fd);

  // attach the door descriptor to the file
  if ((res = ::fattach(dd, initial_path)) == -1) {
    // if busy then detach and try again
    if (errno == EBUSY) {
      ::fdetach(initial_path);
      res = ::fattach(dd, initial_path);
    }
    if (res == -1) {
      ::door_revoke(dd);
      dd = -1;
    }
  }

  // rename file so that clients can attach
  if (dd >= 0) {
    if (::rename(initial_path, door_path) == -1) {
        ::close(dd);
        ::fdetach(initial_path);
        dd = -1;
    }
  }
  if (dd >= 0) {
    set_door_descriptor(dd);
    set_door_path(door_path);
  } else {
    // unable to create door, attach it to file, or rename file into place
    ::unlink(initial_path);
    return -1;
  }

  return 0;
}

/* attach to given JVM */
jvm_t* jvm_attach(pid_t pid) {
    jvm_t* jvm;
    int door_fd, attach_fd, i;

    jvm = (jvm_t*) calloc(1, sizeof(jvm_t));
    if (jvm == NULL) {
        set_jvm_error(JVM_ERR_OUT_OF_MEMORY);
        print_debug("calloc failed in %s at %d\n", __FILE__, __LINE__);
        return NULL;
    }
    jvm->pid = pid;
    attach_fd = -1;

    door_fd = open_door(pid);
    if (door_fd < 0) {
        print_debug("trying to create attach file\n");
        if ((attach_fd = create_attach_file(pid)) < 0) {
            goto quit;
        }

        /* send QUIT signal to the target so that it will
         * check for the attach file.
         */
        if (send_sigquit(pid) != 0) {
            set_jvm_error(JVM_ERR_CANT_SIGNAL);
            print_debug("sending SIGQUIT failed\n");
            goto quit;
        }

        /* give the target VM time to start the attach mechanism */
        do {
            int res;
            RESTARTABLE(poll(0, 0, 200), res);
            door_fd = open_door(pid);
            i++;
        } while (i <= 50 && door_fd == -1);
        if (door_fd < 0) {
            print_debug("Unable to open door to process %d\n", pid);
            goto quit;
        }
    }

quit:
    if (attach_fd >= 0) {
        file_close(attach_fd);
        delete_attach_file(jvm->pid);
    }
    if (door_fd >= 0) {
        jvm->door_fd = door_fd;
        clear_jvm_error();
    } else {
        free(jvm);
        jvm = NULL;
    }
    return jvm;
}

// save the specified memory region to the given file
//
// Note: this function might be called from signal handler (by os::abort()),
// don't allocate heap memory.
//
static void save_memory_to_file(char* addr, size_t size) {

  const char* destfile = PerfMemory::get_perfdata_file_path();
  assert(destfile[0] != '\0', "invalid PerfData file path");

  int result;

  RESTARTABLE(::open(destfile, O_CREAT|O_WRONLY|O_TRUNC, S_IREAD|S_IWRITE),
              result);;
  if (result == OS_ERR) {
    if (PrintMiscellaneous && Verbose) {
      warning("Could not create Perfdata save file: %s: %s\n",
              destfile, strerror(errno));
    }
  } else {
    int fd = result;

    for (size_t remaining = size; remaining > 0;) {

      RESTARTABLE(::write(fd, addr, remaining), result);
      if (result == OS_ERR) {
        if (PrintMiscellaneous && Verbose) {
          warning("Could not write Perfdata save file: %s: %s\n",
                  destfile, strerror(errno));
        }
        break;
      }

      remaining -= (size_t)result;
      addr += result;
    }

    RESTARTABLE(::close(fd), result);
    if (PrintMiscellaneous && Verbose) {
      if (result == OS_ERR) {
        warning("Could not close %s: %s\n", destfile, strerror(errno));
      }
    }
  }
  FREE_C_HEAP_ARRAY(char, destfile, mtInternal);
}

// Check to make sure fd1 and fd2 are referencing the same file system object.
static bool is_same_fsobject(int fd1, int fd2) {
  struct stat statbuf1;
  struct stat statbuf2;
  int result = 0;

  RESTARTABLE(::fstat(fd1, &statbuf1), result);
  if (result == OS_ERR) {
    return false;
  }
  RESTARTABLE(::fstat(fd2, &statbuf2), result);
  if (result == OS_ERR) {
    return false;
  }

  if ((statbuf1.st_ino == statbuf2.st_ino) &&
      (statbuf1.st_dev == statbuf2.st_dev)) {
    return true;
  } else {
    return false;
  }
}

FD
handleOpen(const char *path, int oflag, int mode) {
    FD fd;
    RESTARTABLE(open64(path, oflag, mode), fd);
    if (fd != -1) {
        struct stat64 buf64;
        int result;
        RESTARTABLE(fstat64(fd, &buf64), result);
        if (result != -1) {
            if (S_ISDIR(buf64.st_mode)) {
                close(fd);
                errno = EISDIR;
                fd = -1;
            }
        } else {
            close(fd);
            fd = -1;
        }
    }
    return fd;
}

// (Taken over from Solaris to support the O_NOFOLLOW case on AIX.)
// Check if the given directory file descriptor is considered a secure
// directory for the backing store files. Returns true if the directory
// exists and is considered a secure location. Returns false if the path
// is a symbolic link or if an error occurred.
static bool is_dirfd_secure(int dir_fd) {
  struct stat statbuf;
  int result = 0;

  RESTARTABLE(::fstat(dir_fd, &statbuf), result);
  if (result == OS_ERR) {
    return false;
  }

  // The path exists, now check its mode.
  return is_statbuf_secure(&statbuf);
}

// Check if the given path is considered a secure directory for
// the backing store files. Returns true if the directory exists
// and is considered a secure location. Returns false if the path
// is a symbolic link or if an error occurred.
static bool is_directory_secure(const char* path) {
  struct stat statbuf;
  int result = 0;

  RESTARTABLE(::lstat(path, &statbuf), result);
  if (result == OS_ERR) {
    return false;
  }

  // The path exists, see if it is secure.
  return is_statbuf_secure(&statbuf);
}

inline int    hpi::socket_available(int fd, long *pbytes) {
  if (fd < 0)
    return OS_OK;

  int ret;

  RESTARTABLE(::ioctl(fd, FIONREAD, pbytes), ret);

  //%% note ioctl can return 0 when successful, JVM_SocketAvailable
  // is expected to return 0 on failure and 1 on success to the jdk.

  return (ret == OS_ERR) ? 0 : 1;
}

// If the file .attach_pid<pid> exists in the working directory
// or /tmp then this is the trigger to start the attach mechanism
bool AttachListener::is_init_trigger() {
  if (init_at_startup() || is_initialized()) {
    return false;               // initialized at startup or already initialized
  }
  char fn[32];
  sprintf(fn, ".attach_pid%d", os::current_process_id());
  int ret;
struct stat st;
RESTARTABLE(::stat(fn,&st),ret);
  if (ret == -1) {
sprintf(fn,"%s/.attach_pid%d",os::get_temp_directory(),os::current_process_id());
RESTARTABLE(::stat(fn,&st),ret);
  }
  if (ret == 0) {
    // simple check to avoid starting the attach mechanism when
    // a bogus user creates the file
    if (st.st_uid == geteuid()) {
      init();
      return true;
    }
  }
  return false;
}