path: root/dbus/dbus-sysdeps.c

/* -*- mode: C; c-file-style: "gnu" -*- */
/* dbus-sysdeps.c Wrappers around system/libc features (internal to D-BUS implementation)
 * 
 * Copyright (C) 2002  Red Hat, Inc.
 *
 * Licensed under the Academic Free License version 1.2
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include "dbus-internals.h"
#include "dbus-sysdeps.h"
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/un.h>
#ifdef HAVE_WRITEV
#include <sys/uio.h>
#endif


/**
 * @addtogroup DBusInternalsUtils
 * @{
 */
/**
 * Aborts the program with SIGABRT (dumping core).
 */
void
_dbus_abort (void)
{
  abort ();
  _exit (1); /* in case someone manages to ignore SIGABRT */
}

/**
 * Wrapper for getenv().
 *
 * @param varname name of environment variable
 * @returns value of environment variable or #NULL if unset
 */
const char*
_dbus_getenv (const char *varname)
{  
  return getenv (varname);
}

/**
 * Thin wrapper around the read() system call that appends
 * the data it reads to the DBusString buffer. It appends
 * up to the given count, and returns the same value
 * and same errno as read(). The only exception is that
 * _dbus_read() handles EINTR for you.
 *
 * @param fd the file descriptor to read from
 * @param buffer the buffer to append data to
 * @param count the amount of data to read
 * @returns the number of bytes read or -1
 */
int
_dbus_read (int               fd,
            DBusString       *buffer,
            int               count)
{
  int bytes_read;
  int start;
  char *data;

  _dbus_assert (count >= 0);
  
  start = _dbus_string_get_length (buffer);

  if (!_dbus_string_lengthen (buffer, count))
    {
      errno = ENOMEM;
      return -1;
    }

  _dbus_string_get_data_len (buffer, &data, start, count);

 again:
  
  bytes_read = read (fd, data, count);

  if (bytes_read < 0)
    {
      if (errno == EINTR)
        goto again;
      else
        {
          /* put length back (note that this doesn't actually realloc anything) */
          _dbus_string_set_length (buffer, start);
          return -1;
        }
    }
  else
    {
      /* put length back (doesn't actually realloc) */
      _dbus_string_set_length (buffer, start + bytes_read);
      return bytes_read;
    }
}

/**
 * Thin wrapper around the write() system call that writes a part of a
 * DBusString and handles EINTR for you.
 * 
 * @param fd the file descriptor to write
 * @param buffer the buffer to write data from
 * @param start the first byte in the buffer to write
 * @param len the number of bytes to try to write
 * @returns the number of bytes written or -1 on error
 */
int
_dbus_write (int               fd,
             const DBusString *buffer,
             int               start,
             int               len)
{
  const char *data;
  int bytes_written;
  
  _dbus_string_get_const_data_len (buffer, &data, start, len);
  
 again:

  bytes_written = write (fd, data, len);

  if (errno == EINTR)
    goto again;

  return bytes_written;
}

/**
 * Like _dbus_write() but will use writev() if possible
 * to write both buffers in sequence. The return value
 * is the number of bytes written in the first buffer,
 * plus the number written in the second. If the first
 * buffer is written successfully and an error occurs
 * writing the second, the number of bytes in the first
 * is returned (i.e. the error is ignored), on systems that
 * don't have writev. Handles EINTR for you.
 * The second buffer may be #NULL.
 *
 * @param fd the file descriptor
 * @param buffer1 first buffer
 * @param start1 first byte to write in first buffer
 * @param len1 number of bytes to write from first buffer
 * @param buffer2 second buffer, or #NULL
 * @param start2 first byte to write in second buffer
 * @param len2 number of bytes to write in second buffer
 * @returns total bytes written from both buffers, or -1 on error
 */
int
_dbus_write_two (int               fd,
                 const DBusString *buffer1,
                 int               start1,
                 int               len1,
                 const DBusString *buffer2,
                 int               start2,
                 int               len2)
{
  _dbus_assert (buffer1 != NULL);
  _dbus_assert (start1 >= 0);
  _dbus_assert (start2 >= 0);
  _dbus_assert (len1 >= 0);
  _dbus_assert (len2 >= 0);
  
#ifdef HAVE_WRITEV
  {
    struct iovec vectors[2];
    const char *data1;
    const char *data2;
    int bytes_written;

    _dbus_string_get_const_data_len (buffer1, &data1, start1, len1);

    if (buffer2 != NULL)
      _dbus_string_get_const_data_len (buffer2, &data2, start2, len2);
    else
      {
        data2 = NULL;
        start2 = 0;
        len2 = 0;
      }
   
    vectors[0].iov_base = (char*) data1;
    vectors[0].iov_len = len1;
    vectors[1].iov_base = (char*) data2;
    vectors[1].iov_len = len2;

  again:
   
    bytes_written = writev (fd,
                            vectors,
                            data2 ? 2 : 1);

    if (errno == EINTR)
      goto again;
   
    return bytes_written;
  }
#else /* HAVE_WRITEV */
  {
    int ret1;
    
    ret1 = _dbus_write (fd, buffer1, start1, len1);
    if (ret1 == len1 && buffer2 != NULL)
      {
        ret2 = _dbus_write (fd, buffer2, start2, len2);
        if (ret2 < 0)
          ret2 = 0; /* we can't report an error as the first write was OK */
       
        return ret1 + ret2;
      }
    else
      return ret1;
  }
#endif /* !HAVE_WRITEV */   
}

/**
 * Creates a socket and connects it to the UNIX domain socket at the
 * given path.  The connection fd is returned, and is set up as
 * nonblocking.
 *
 * @param path the path to UNIX domain socket
 * @param result return location for error code
 * @returns connection file descriptor or -1 on error
 */
int
_dbus_connect_unix_socket (const char     *path,
                           DBusResultCode *result)
{
  int fd;
  struct sockaddr_un addr;  
  
  fd = socket (AF_LOCAL, SOCK_STREAM, 0);

  if (fd < 0)
    {
      dbus_set_result (result,
                       _dbus_result_from_errno (errno));
      
      _dbus_verbose ("Failed to create socket: %s\n",
                     _dbus_strerror (errno)); 
      
      return -1;
    }

  _DBUS_ZERO (addr);
  addr.sun_family = AF_LOCAL;
  strncpy (addr.sun_path, path, _DBUS_MAX_SUN_PATH_LENGTH);
  addr.sun_path[_DBUS_MAX_SUN_PATH_LENGTH] = '\0';
  
  if (connect (fd, (struct sockaddr*) &addr, sizeof (addr)) < 0)
    {      
      dbus_set_result (result,
                       _dbus_result_from_errno (errno));

      _dbus_verbose ("Failed to connect to socket %s: %s\n",
                     path, _dbus_strerror (errno));

      close (fd);
      fd = -1;
      
      return -1;
    }

  if (!_dbus_set_fd_nonblocking (fd, result))
    {
      close (fd);
      fd = -1;

      return -1;
    }

  return fd;
}

/**
 * Creates a socket and binds it to the given path,
 * then listens on the socket. The socket is
 * set to be nonblocking. 
 *
 * @param path the socket name
 * @param result return location for errors
 * @returns the listening file descriptor or -1 on error
 */
int
_dbus_listen_unix_socket (const char     *path,
                          DBusResultCode *result)
{
  int listen_fd;
  struct sockaddr_un addr;

  listen_fd = socket (AF_LOCAL, SOCK_STREAM, 0);

  if (listen_fd < 0)
    {
      dbus_set_result (result, _dbus_result_from_errno (errno));
      _dbus_verbose ("Failed to create socket \"%s\": %s\n",
                     path, _dbus_strerror (errno));
      return -1;
    }

  _DBUS_ZERO (addr);
  addr.sun_family = AF_LOCAL;
  strncpy (addr.sun_path, path, _DBUS_MAX_SUN_PATH_LENGTH);
  addr.sun_path[_DBUS_MAX_SUN_PATH_LENGTH] = '\0';
  
  if (bind (listen_fd, (struct sockaddr*) &addr, SUN_LEN (&addr)) < 0)
    {
      dbus_set_result (result, _dbus_result_from_errno (errno));
      _dbus_verbose ("Failed to bind socket \"%s\": %s\n",
                     path, _dbus_strerror (errno));
      close (listen_fd);
      return -1;
    }

  if (listen (listen_fd, 30 /* backlog */) < 0)
    {
      dbus_set_result (result, _dbus_result_from_errno (errno));      
      _dbus_verbose ("Failed to listen on socket \"%s\": %s\n",
                     path, _dbus_strerror (errno));
      close (listen_fd);
      return -1;
    }

  if (!_dbus_set_fd_nonblocking (listen_fd, result))
    {
      close (listen_fd);
      return -1;
    }
  
  return listen_fd;
}

/**
 * Accepts a connection on a listening UNIX socket.
 * Specific to UNIX domain sockets because we might
 * add extra args to this function later to get client
 * credentials. Handles EINTR for you.
 *
 * @param listen_fd the listen file descriptor
 * @returns the connection fd of the client, or -1 on error
 */
int
_dbus_accept_unix_socket  (int listen_fd)
{
  int client_fd;
  
 retry:
  client_fd = accept (listen_fd, NULL, NULL);
  
  if (client_fd < 0)
    {
      if (errno == EINTR)
        goto retry;
    }

  return client_fd;
}

/** @} */

/**
 * @addtogroup DBusString
 *
 * @{
 */
/**
 * Appends an integer to a DBusString.
 * 
 * @param str the string
 * @param value the integer value
 * @returns #FALSE if not enough memory or other failure.
 */
dbus_bool_t
_dbus_string_append_int (DBusString *str,
                         long        value)
{
  /* this calculation is from comp.lang.c faq */
#define MAX_LONG_LEN ((sizeof (long) * 8 + 2) / 3 + 1)  /* +1 for '-' */
  int orig_len;
  int i;
  char *buf;
  
  orig_len = _dbus_string_get_length (str);

  if (!_dbus_string_lengthen (str, MAX_LONG_LEN))
    return FALSE;

  _dbus_string_get_data_len (str, &buf, orig_len, MAX_LONG_LEN);

  snprintf (buf, MAX_LONG_LEN, "%ld", value);

  i = 0;
  while (*buf)
    {
      ++buf;
      ++i;
    }
  
  _dbus_string_shorten (str, MAX_LONG_LEN - i);
  
  return TRUE;
}

/**
 * Appends a double to a DBusString.
 * 
 * @param str the string
 * @param value the floating point value
 * @returns #FALSE if not enough memory or other failure.
 */
dbus_bool_t
_dbus_string_append_double (DBusString *str,
                            double      value)
{
#define MAX_DOUBLE_LEN 64 /* this is completely made up :-/ */
  int orig_len;
  char *buf;
  int i;
  
  orig_len = _dbus_string_get_length (str);

  if (!_dbus_string_lengthen (str, MAX_DOUBLE_LEN))
    return FALSE;

  _dbus_string_get_data_len (str, &buf, orig_len, MAX_DOUBLE_LEN);

  snprintf (buf, MAX_LONG_LEN, "%g", value);

  i = 0;
  while (*buf)
    {
      ++buf;
      ++i;
    }
  
  _dbus_string_shorten (str, MAX_DOUBLE_LEN - i);
  
  return TRUE;
}

/**
 * Parses an integer contained in a DBusString. Either return parameter
 * may be #NULL if you aren't interested in it. The integer is parsed
 * and stored in value_return. Return parameters are not initialized
 * if the function returns #FALSE.
 *
 * @param str the string
 * @param start the byte index of the start of the integer
 * @param value_return return location of the integer value or #NULL
 * @param end_return return location of the end of the integer, or #NULL
 * @returns #TRUE on success
 */
dbus_bool_t
_dbus_string_parse_int (const DBusString *str,
                        int               start,
                        long             *value_return,
                        int              *end_return)
{
  long v;
  const char *p;
  char *end;

  _dbus_string_get_const_data_len (str, &p, start,
                                   _dbus_string_get_length (str) - start);

  end = NULL;
  errno = 0;
  v = strtol (p, &end, 0);
  if (end == NULL || end == p || errno != 0)
    return FALSE;

  if (value_return)
    *value_return = v;
  if (end_return)
    *end_return = (end - p);

  return TRUE;
}

/**
 * Parses a floating point number contained in a DBusString. Either
 * return parameter may be #NULL if you aren't interested in it. The
 * integer is parsed and stored in value_return. Return parameters are
 * not initialized if the function returns #FALSE.
 *
 * @todo this function is currently locale-dependent. Should
 * ask alexl to relicense g_ascii_strtod() code and put that in
 * here instead, so it's locale-independent.
 *
 * @param str the string
 * @param start the byte index of the start of the float
 * @param value_return return location of the float value or #NULL
 * @param end_return return location of the end of the float, or #NULL
 * @returns #TRUE on success
 */
dbus_bool_t
_dbus_string_parse_double (const DBusString *str,
                           int               start,
                           double           *value_return,
                           int              *end_return)
{
  double v;
  const char *p;
  char *end;

  _dbus_warn ("_dbus_string_parse_double() needs to be made locale-independent\n");
  
  _dbus_string_get_const_data_len (str, &p, start,
                                   _dbus_string_get_length (str) - start);

  end = NULL;
  errno = 0;
  v = strtod (p, &end);
  if (end == NULL || end == p || errno != 0)
    return FALSE;

  if (value_return)
    *value_return = v;
  if (end_return)
    *end_return = (end - p);

  return TRUE;
}

/** @} end of DBusString */