Module: PhusionPassenger::NativeSupport

Defined in:
ext/phusion_passenger/native_support.c

Constant Summary collapse

UNIX_PATH_MAX =

The maximum length of a Unix socket path, including terminating null.

INT2NUM(sizeof(addr.sun_path))

Class Method Summary collapse

Class Method Details

.accept(fileno) ⇒ Object

Accept a new client from the given socket.

  • fileno (integer): The file descriptor of the server socket.

  • Returns: The accepted client’s file descriptor.

  • Raises SystemCallError if something went wrong.



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# File 'ext/phusion_passenger/native_support.c', line 240

static VALUE
f_accept(VALUE self, VALUE fileno) {
  int fd = accept(NUM2INT(fileno), NULL, NULL);
  if (fd == -1) {
    rb_sys_fail("accept() failed");
    return Qnil;
  } else {
    return INT2NUM(fd);
  }
}

.close_all_file_descriptors(exceptions) ⇒ Object

Close all file descriptors, except those given in the exceptions array. For example, the following would close all file descriptors except standard input (0) and standard output (1).

close_all_file_descriptors([0, 1])



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# File 'ext/phusion_passenger/native_support.c', line 260

static VALUE
close_all_file_descriptors(VALUE self, VALUE exceptions) {
  long i, j;
  
  for (i = sysconf(_SC_OPEN_MAX) - 1; i >= 0; i--) {
    int is_exception = 0;
    for (j = 0; j < RARRAY_LEN(exceptions) && !is_exception; j++) {
      long fd = NUM2INT(rb_ary_entry(exceptions, j));
      is_exception = i == fd;
    }
    if (!is_exception) {
      close(i);
    }
  }
  return Qnil;
}

.create_unix_socket(filename, backlog) ⇒ Object

Create a SOCK_STREAM server Unix socket. Unlike Ruby’s UNIXServer class, this function is also able to create Unix sockets on the abstract namespace by prepending the filename with a null byte.

  • filename (string): The filename of the Unix socket to create.

  • backlog (integer): The backlog to use for listening on the socket.

  • Returns: The file descriptor of the created Unix socket, as an integer.

  • Raises SystemCallError if something went wrong.



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# File 'ext/phusion_passenger/native_support.c', line 191

static VALUE
create_unix_socket(VALUE self, VALUE filename, VALUE backlog) {
  int fd, ret;
  struct sockaddr_un addr;
  char *filename_str;
  long filename_length;
  
  filename_str = RSTRING_PTR(filename);
  filename_length = RSTRING_LEN(filename);
  
  fd = socket(PF_UNIX, SOCK_STREAM, 0);
  if (fd == -1) {
    rb_sys_fail("Cannot create a Unix socket");
    return Qnil;
  }
  
  addr.sun_family = AF_UNIX;
  memcpy(addr.sun_path, filename_str, MIN(filename_length, sizeof(addr.sun_path)));
  addr.sun_path[sizeof(addr.sun_path) - 1] = '\0';
  
  ret = bind(fd, (const struct sockaddr *) &addr, sizeof(addr));
  if (ret == -1) {
    int e = errno;
    close(fd);
    errno = e;
    rb_sys_fail("Cannot bind Unix socket");
    return Qnil;
  }
  
  ret = listen(fd, NUM2INT(backlog));
  if (ret == -1) {
    int e = errno;
    close(fd);
    errno = e;
    rb_sys_fail("Cannot listen on Unix socket");
    return Qnil;
  }
  return INT2NUM(fd);
}

.disable_stdio_buffering ⇒ Object

Disables any kind of buffering on the C stdout and stderr variables, so that fprintf() on stdout and stderr have immediate effect.



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# File 'ext/phusion_passenger/native_support.c', line 283

static VALUE
disable_stdio_buffering() {
  setvbuf(stdout, NULL, _IONBF, 0);
  setvbuf(stderr, NULL, _IONBF, 0);
  return Qnil;
}

.recv_fd(socket_fd) ⇒ Object

Receive a file descriptor from the given Unix socket. Returns the received file descriptor as an integer. Raises SystemCallError if something went wrong.

You do not have call this method directly. A convenience wrapper is provided by IO#recv_io.



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# File 'ext/phusion_passenger/native_support.c', line 124

static VALUE
recv_fd(VALUE self, VALUE socket_fd) {
  struct msghdr msg;
  struct iovec vec;
  char dummy[1];
  #if defined(__APPLE__) || defined(__SOLARIS__) || defined(__arm__)
    // File descriptor passing macros (CMSG_*) seem to be broken
    // on 64-bit MacOS X. This structure works around the problem.
    struct {
      struct cmsghdr header;
      int fd;
    } control_data;
    #define EXPECTED_CMSG_LEN sizeof(control_data)
  #else
    char control_data[CMSG_SPACE(sizeof(int))];
    #define EXPECTED_CMSG_LEN CMSG_LEN(sizeof(int))
  #endif
  struct cmsghdr *control_header;

  msg.msg_name    = NULL;
  msg.msg_namelen = 0;
  
  dummy[0]       = '\0';
  vec.iov_base   = dummy;
  vec.iov_len    = sizeof(dummy);
  msg.msg_iov    = &vec;
  msg.msg_iovlen = 1;

  msg.msg_control    = (caddr_t) &control_data;
  msg.msg_controllen = sizeof(control_data);
  msg.msg_flags      = 0;
  
  if (recvmsg(NUM2INT(socket_fd), &msg, 0) == -1) {
    rb_sys_fail("Cannot read file descriptor with recvmsg()");
    return Qnil;
  }
  
  control_header = CMSG_FIRSTHDR(&msg);
  if (control_header == NULL) {
    rb_raise(rb_eIOError, "No valid file descriptor received.");
    return Qnil;
  }
  if (control_header->cmsg_len   != EXPECTED_CMSG_LEN
   || control_header->cmsg_level != SOL_SOCKET
   || control_header->cmsg_type  != SCM_RIGHTS) {
    rb_raise(rb_eIOError, "No valid file descriptor received.");
    return Qnil;
  }
  #if defined(__APPLE__) || defined(__SOLARIS__) || defined(__arm__)
    return INT2NUM(control_data.fd);
  #else
    return INT2NUM(*((int *) CMSG_DATA(control_header)));
  #endif
}

.send_fd(socket_fd, fd_to_send) ⇒ Object

Send a file descriptor over the given Unix socket. You do not have to call this function directly. A convenience wrapper is provided by IO#send_io.

  • socket_fd (integer): The file descriptor of the socket.

  • fd_to_send (integer): The file descriptor to send.

  • Raises SystemCallError if something went wrong.



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# File 'ext/phusion_passenger/native_support.c', line 64

static VALUE
send_fd(VALUE self, VALUE socket_fd, VALUE fd_to_send) {
  struct msghdr msg;
  struct iovec vec;
  char dummy[1];
  #if defined(__APPLE__) || defined(__SOLARIS__) || defined(__arm__)
    struct {
      struct cmsghdr header;
      int fd;
    } control_data;
  #else
    char control_data[CMSG_SPACE(sizeof(int))];
  #endif
  struct cmsghdr *control_header;
  int control_payload;
  
  msg.msg_name = NULL;
  msg.msg_namelen = 0;
  
  /* Linux and Solaris require msg_iov to be non-NULL. */
  dummy[0]       = '\0';
  vec.iov_base   = dummy;
  vec.iov_len    = sizeof(dummy);
  msg.msg_iov    = &vec;
  msg.msg_iovlen = 1;
  
  msg.msg_control    = (caddr_t) &control_data;
  msg.msg_controllen = sizeof(control_data);
  msg.msg_flags      = 0;
  
  control_header = CMSG_FIRSTHDR(&msg);
  control_header->cmsg_level = SOL_SOCKET;
  control_header->cmsg_type  = SCM_RIGHTS;
  control_payload = NUM2INT(fd_to_send);
  #if defined(__APPLE__) || defined(__SOLARIS__) || defined(__arm__)
    control_header->cmsg_len = sizeof(control_data);
    control_data.fd = control_payload;
  #else
    control_header->cmsg_len = CMSG_LEN(sizeof(int));
    memcpy(CMSG_DATA(control_header), &control_payload, sizeof(int));
  #endif
  
  if (sendmsg(NUM2INT(socket_fd), &msg, 0) == -1) {
    rb_sys_fail("sendmsg(2)");
    return Qnil;
  }
  
  return Qnil;
}

.switch_user(username, uid, gid) ⇒ Object

Ruby’s implementations of initgroups, setgid and setuid are broken various ways, sigh… Ruby’s setgid and setuid can’t handle negative UIDs and initgroups is just broken. Work around it by using our own implementation.



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# File 'ext/phusion_passenger/native_support.c', line 296

static VALUE
switch_user(VALUE self, VALUE username, VALUE uid, VALUE gid) {
  uid_t the_uid = NUM2LL(uid);
  gid_t the_gid = NUM2LL(gid);

  if (initgroups(RSTRING_PTR(username), the_gid) == -1) {
    rb_sys_fail("initgroups");
  }
  if (setgid(the_gid) == -1) {
    rb_sys_fail("setgid");
  }
  if (setuid(the_uid) == -1) {
    rb_sys_fail("setuid");
  }
  return Qnil;
}