dbus-internals.c revision 2f38c959212d98e2194139daa9120fda37415b4f 
1/* -*- mode: C; c-file-style: "gnu" -*- */
2/* dbus-internals.c  random utility stuff (internal to D-BUS implementation)
3 *
4 * Copyright (C) 2002  Red Hat, Inc.
5 *
6 * Licensed under the Academic Free License version 1.2
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
21 *
22 */
23#include "dbus-internals.h"
24#include "dbus-protocol.h"
25#include "dbus-test.h"
26#include <stdio.h>
27#include <stdarg.h>
28#include <string.h>
29#include <sys/types.h>
30#include <errno.h>
31#include <unistd.h>
32#include <fcntl.h>
33#include <stdlib.h>
34
35/**
36 * @defgroup DBusInternals D-BUS internal implementation details
37 * @brief Documentation useful when developing or debugging D-BUS itself.
38 *
39 */
40
41/**
42 * @defgroup DBusInternalsUtils Utilities and portability
43 * @ingroup DBusInternals
44 * @brief Utility functions (_dbus_assert(), _dbus_warn(), etc.)
45 * @{
46 */
47
48/**
49 * @def _dbus_assert
50 *
51 * Aborts with an error message if the condition is false.
52 *
53 * @param condition condition which must be true.
54 */
55
56/**
57 * @def _dbus_assert_not_reached
58 *
59 * Aborts with an error message if called.
60 * The given explanation will be printed.
61 *
62 * @param explanation explanation of what happened if the code was reached.
63 */
64
65/**
66 * @def _DBUS_N_ELEMENTS
67 *
68 * Computes the number of elements in a fixed-size array using
69 * sizeof().
70 *
71 * @param array the array to count elements in.
72 */
73
74/**
75 * @def _DBUS_POINTER_TO_INT
76 *
77 * Safely casts a void* to an integer; should only be used on void*
78 * that actually contain integers, for example one created with
79 * _DBUS_INT_TO_POINTER.  Only guaranteed to preserve 32 bits.
80 * (i.e. it's used to store 32-bit ints in pointers, but
81 * can't be used to store 64-bit pointers in ints.)
82 *
83 * @param pointer pointer to extract an integer from.
84 */
85/**
86 * @def _DBUS_INT_TO_POINTER
87 *
88 * Safely stuffs an integer into a pointer, to be extracted later with
89 * _DBUS_POINTER_TO_INT. Only guaranteed to preserve 32 bits.
90 *
91 * @param integer the integer to stuff into a pointer.
92 */
93/**
94 * @def _DBUS_ZERO
95 *
96 * Sets all bits in an object to zero.
97 *
98 * @param object the object to be zeroed.
99 */
100/**
101 * @def _DBUS_INT_MIN
102 *
103 * Minimum value of type "int"
104 */
105/**
106 * @def _DBUS_INT_MAX
107 *
108 * Maximum value of type "int"
109 */
110/**
111 * @def _DBUS_MAX_SUN_PATH_LENGTH
112 *
113 * Maximum length of the path to a UNIX domain socket,
114 * sockaddr_un::sun_path member. POSIX requires that all systems
115 * support at least 100 bytes here, including the nul termination.
116 * We use 99 for the max value to allow for the nul.
117 *
118 * We could probably also do sizeof (addr.sun_path)
119 * but this way we are the same on all platforms
120 * which is probably a good idea.
121 */
122
123/**
124 * @typedef DBusForeachFunction
125 *
126 * Used to iterate over each item in a collection, such as
127 * a DBusList.
128 */
129
130/**
131 * Prints a warning message to stderr.
132 *
133 * @param format printf-style format string.
134 */
135void
136_dbus_warn (const char *format,
137            ...)
138{
139  /* FIXME not portable enough? */
140  va_list args;
141
142  va_start (args, format);
143  vfprintf (stderr, format, args);
144  va_end (args);
145}
146
147/**
148 * Prints a warning message to stderr
149 * if the user has enabled verbose mode.
150 * This is the real function implementation,
151 * use _dbus_verbose() macro in code.
152 *
153 * @param format printf-style format string.
154 */
155void
156_dbus_verbose_real (const char *format,
157                    ...)
158{
159  va_list args;
160  static dbus_bool_t verbose = TRUE;
161  static dbus_bool_t initted = FALSE;
162
163  /* things are written a bit oddly here so that
164   * in the non-verbose case we just have the one
165   * conditional and return immediately.
166   */
167  if (!verbose)
168    return;
169
170  if (!initted)
171    {
172      verbose = _dbus_getenv ("DBUS_VERBOSE") != NULL;
173      initted = TRUE;
174      if (!verbose)
175        return;
176    }
177
178  va_start (args, format);
179  vfprintf (stderr, format, args);
180  va_end (args);
181}
182
183/**
184 * Converts a UNIX errno into a DBusResultCode.
185 *
186 * @todo should cover more errnos, specifically those
187 * from open().
188 *
189 * @param error_number the errno.
190 * @returns the result code.
191 */
192DBusResultCode
193_dbus_result_from_errno (int error_number)
194{
195  switch (error_number)
196    {
197    case 0:
198      return DBUS_RESULT_SUCCESS;
199
200#ifdef EPROTONOSUPPORT
201    case EPROTONOSUPPORT:
202      return DBUS_RESULT_NOT_SUPPORTED;
203#endif
204#ifdef EAFNOSUPPORT
205    case EAFNOSUPPORT:
206      return DBUS_RESULT_NOT_SUPPORTED;
207#endif
208#ifdef ENFILE
209    case ENFILE:
210      return DBUS_RESULT_LIMITS_EXCEEDED; /* kernel out of memory */
211#endif
212#ifdef EMFILE
213    case EMFILE:
214      return DBUS_RESULT_LIMITS_EXCEEDED;
215#endif
216#ifdef EACCES
217    case EACCES:
218      return DBUS_RESULT_ACCESS_DENIED;
219#endif
220#ifdef EPERM
221    case EPERM:
222      return DBUS_RESULT_ACCESS_DENIED;
223#endif
224#ifdef ENOBUFS
225    case ENOBUFS:
226      return DBUS_RESULT_NO_MEMORY;
227#endif
228#ifdef ENOMEM
229    case ENOMEM:
230      return DBUS_RESULT_NO_MEMORY;
231#endif
232#ifdef EINVAL
233    case EINVAL:
234      return DBUS_RESULT_FAILED;
235#endif
236#ifdef EBADF
237    case EBADF:
238      return DBUS_RESULT_FAILED;
239#endif
240#ifdef EFAULT
241    case EFAULT:
242      return DBUS_RESULT_FAILED;
243#endif
244#ifdef ENOTSOCK
245    case ENOTSOCK:
246      return DBUS_RESULT_FAILED;
247#endif
248#ifdef EISCONN
249    case EISCONN:
250      return DBUS_RESULT_FAILED;
251#endif
252#ifdef ECONNREFUSED
253    case ECONNREFUSED:
254      return DBUS_RESULT_NO_SERVER;
255#endif
256#ifdef ETIMEDOUT
257    case ETIMEDOUT:
258      return DBUS_RESULT_TIMEOUT;
259#endif
260#ifdef ENETUNREACH
261    case ENETUNREACH:
262      return DBUS_RESULT_NO_NETWORK;
263#endif
264#ifdef EADDRINUSE
265    case EADDRINUSE:
266      return DBUS_RESULT_ADDRESS_IN_USE;
267#endif
268#ifdef EEXIST
269    case EEXIST:
270      return DBUS_RESULT_FILE_NOT_FOUND;
271#endif
272#ifdef ENOENT
273    case ENOENT:
274      return DBUS_RESULT_FILE_NOT_FOUND;
275#endif
276    }
277
278  return DBUS_RESULT_FAILED;
279}
280
281/**
282 * Duplicates a string. Result must be freed with
283 * dbus_free(). Returns #NULL if memory allocation fails.
284 * If the string to be duplicated is #NULL, returns #NULL.
285 *
286 * @param str string to duplicate.
287 * @returns newly-allocated copy.
288 */
289char*
290_dbus_strdup (const char *str)
291{
292  int len;
293  char *copy;
294
295  if (str == NULL)
296    return NULL;
297
298  len = strlen (str);
299
300  copy = dbus_malloc (len + 1);
301  if (copy == NULL)
302    return NULL;
303
304  memcpy (copy, str, len + 1);
305
306  return copy;
307}
308
309/**
310 * Sets a file descriptor to be nonblocking.
311 *
312 * @param fd the file descriptor.
313 * @param result address of result code.
314 * @returns #TRUE on success.
315 */
316dbus_bool_t
317_dbus_set_fd_nonblocking (int             fd,
318                          DBusResultCode *result)
319{
320  int val;
321
322  val = fcntl (fd, F_GETFL, 0);
323  if (val < 0)
324    {
325      dbus_set_result (result, _dbus_result_from_errno (errno));
326      _dbus_verbose ("Failed to get flags for fd %d: %s\n", fd,
327                     _dbus_strerror (errno));
328      return FALSE;
329    }
330
331  if (fcntl (fd, F_SETFL, val | O_NONBLOCK) < 0)
332    {
333      dbus_set_result (result, _dbus_result_from_errno (errno));
334      _dbus_verbose ("Failed to set fd %d nonblocking: %s\n",
335                     fd, _dbus_strerror (errno));
336
337      return FALSE;
338    }
339
340  return TRUE;
341}
342
343/**
344 * Returns a string describing the given type.
345 *
346 * @param type the type to describe
347 * @returns a constant string describing the type
348 */
349const char *
350_dbus_type_to_string (int type)
351{
352  switch (type)
353    {
354    case DBUS_TYPE_INVALID:
355      return "invalid";
356    case DBUS_TYPE_NIL:
357      return "nil";
358    case DBUS_TYPE_INT32:
359      return "int32";
360    case DBUS_TYPE_UINT32:
361      return "uint32";
362    case DBUS_TYPE_DOUBLE:
363      return "double";
364    case DBUS_TYPE_STRING:
365      return "string";
366    case DBUS_TYPE_INT32_ARRAY:
367      return "int32 array";
368    case DBUS_TYPE_UINT32_ARRAY:
369      return "uint32 array";
370    case DBUS_TYPE_DOUBLE_ARRAY:
371      return "double array";
372    case DBUS_TYPE_BYTE_ARRAY:
373      return "byte array";
374    case DBUS_TYPE_STRING_ARRAY:
375      return "string array";
376    default:
377      return "unknown";
378    }
379}
380
381#ifdef DBUS_BUILD_TESTS
382static int fail_alloc_counter = _DBUS_INT_MAX;
383/**
384 * Sets the number of allocations until we simulate a failed
385 * allocation. If set to 0, the next allocation to run
386 * fails; if set to 1, one succeeds then the next fails; etc.
387 * Set to _DBUS_INT_MAX to not fail anything.
388 *
389 * @param until_next_fail number of successful allocs before one fails
390 */
391void
392_dbus_set_fail_alloc_counter (int until_next_fail)
393{
394  fail_alloc_counter = until_next_fail;
395}
396
397/**
398 * Gets the number of successful allocs until we'll simulate
399 * a failed alloc.
400 *
401 * @returns current counter value
402 */
403int
404_dbus_get_fail_alloc_counter (void)
405{
406  return fail_alloc_counter;
407}
408
409/**
410 * Called when about to alloc some memory; if
411 * it returns #TRUE, then the allocation should
412 * fail. If it returns #FALSE, then the allocation
413 * should not fail.
414 *
415 * @returns #TRUE if this alloc should fail
416 */
417dbus_bool_t
418_dbus_decrement_fail_alloc_counter (void)
419{
420  if (fail_alloc_counter <= 0)
421    {
422      fail_alloc_counter = _DBUS_INT_MAX;
423      return TRUE;
424    }
425  else
426    {
427      fail_alloc_counter -= 1;
428      return FALSE;
429    }
430}
431#endif /* DBUS_BUILD_TESTS */
432
433/** @} */
434