1 /* -*- mode: C; c-file-style: "gnu" -*- */
2 /* dbus-internals.c random utility stuff (internal to D-Bus implementation)
4 * Copyright (C) 2002, 2003 Red Hat, Inc.
6 * Licensed under the Academic Free License version 2.1
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.
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.
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
23 #include "dbus-internals.h"
24 #include "dbus-protocol.h"
25 #include "dbus-test.h"
32 * @defgroup DBusInternals D-Bus internal implementation details
33 * @brief Documentation useful when developing or debugging D-Bus itself.
38 * @defgroup DBusInternalsUtils Utilities and portability
39 * @ingroup DBusInternals
40 * @brief Utility functions (_dbus_assert(), _dbus_warn(), etc.)
47 * Aborts with an error message if the condition is false.
49 * @param condition condition which must be true.
53 * @def _dbus_assert_not_reached
55 * Aborts with an error message if called.
56 * The given explanation will be printed.
58 * @param explanation explanation of what happened if the code was reached.
62 * @def _DBUS_N_ELEMENTS
64 * Computes the number of elements in a fixed-size array using
67 * @param array the array to count elements in.
71 * @def _DBUS_POINTER_TO_INT
73 * Safely casts a void* to an integer; should only be used on void*
74 * that actually contain integers, for example one created with
75 * _DBUS_INT_TO_POINTER. Only guaranteed to preserve 32 bits.
76 * (i.e. it's used to store 32-bit ints in pointers, but
77 * can't be used to store 64-bit pointers in ints.)
79 * @param pointer pointer to extract an integer from.
82 * @def _DBUS_INT_TO_POINTER
84 * Safely stuffs an integer into a pointer, to be extracted later with
85 * _DBUS_POINTER_TO_INT. Only guaranteed to preserve 32 bits.
87 * @param integer the integer to stuff into a pointer.
92 * Sets all bits in an object to zero.
94 * @param object the object to be zeroed.
97 * @def _DBUS_INT16_MIN
99 * Minimum value of type "int16"
102 * @def _DBUS_INT16_MAX
104 * Maximum value of type "int16"
107 * @def _DBUS_UINT16_MAX
109 * Maximum value of type "uint16"
113 * @def _DBUS_INT32_MIN
115 * Minimum value of type "int32"
118 * @def _DBUS_INT32_MAX
120 * Maximum value of type "int32"
123 * @def _DBUS_UINT32_MAX
125 * Maximum value of type "uint32"
131 * Minimum value of type "int"
136 * Maximum value of type "int"
139 * @def _DBUS_UINT_MAX
141 * Maximum value of type "uint"
145 * @typedef DBusForeachFunction
147 * Used to iterate over each item in a collection, such as
152 * @def _DBUS_LOCK_NAME
154 * Expands to name of a global lock variable.
158 * @def _DBUS_DEFINE_GLOBAL_LOCK
160 * Defines a global lock variable with the given name.
161 * The lock must be added to the list to initialize
162 * in dbus_threads_init().
166 * @def _DBUS_DECLARE_GLOBAL_LOCK
168 * Expands to declaration of a global lock defined
169 * with _DBUS_DEFINE_GLOBAL_LOCK.
170 * The lock must be added to the list to initialize
171 * in dbus_threads_init().
177 * Locks a global lock
183 * Unlocks a global lock
187 * Fixed "out of memory" error message, just to avoid
188 * making up a different string every time and wasting
191 const char _dbus_no_memory_message[] = "Not enough memory";
193 static dbus_bool_t warn_initted = FALSE;
194 static dbus_bool_t fatal_warnings = FALSE;
195 static dbus_bool_t fatal_warnings_on_check_failed = TRUE;
203 s = _dbus_getenv ("DBUS_FATAL_WARNINGS");
208 fatal_warnings = FALSE;
209 fatal_warnings_on_check_failed = FALSE;
213 fatal_warnings = TRUE;
214 fatal_warnings_on_check_failed = TRUE;
218 fprintf(stderr, "DBUS_FATAL_WARNINGS should be set to 0 or 1 if set, not '%s'",
228 * Prints a warning message to stderr. Can optionally be made to exit
229 * fatally by setting DBUS_FATAL_WARNINGS, but this is rarely
230 * used. This function should be considered pretty much equivalent to
231 * fprintf(stderr). _dbus_warn_check_failed() on the other hand is
232 * suitable for use when a programming mistake has been made.
234 * @param format printf-style format string.
237 _dbus_warn (const char *format,
245 va_start (args, format);
246 vfprintf (stderr, format, args);
257 * Prints a "critical" warning to stderr when an assertion fails;
258 * differs from _dbus_warn primarily in that it prefixes the pid and
259 * defaults to fatal. This should be used only when a programming
260 * error has been detected. (NOT for unavoidable errors that an app
261 * might handle - those should be returned as DBusError.) Calling this
262 * means "there is a bug"
265 _dbus_warn_check_failed(const char *format,
273 fprintf (stderr, "process %lu: ", _dbus_getpid ());
275 va_start (args, format);
276 vfprintf (stderr, format, args);
279 if (fatal_warnings_on_check_failed)
286 #ifdef DBUS_ENABLE_VERBOSE_MODE
288 static dbus_bool_t verbose_initted = FALSE;
289 static dbus_bool_t verbose = TRUE;
291 #define PTHREAD_IN_VERBOSE 0
292 #if PTHREAD_IN_VERBOSE
297 _dbus_verbose_init (void)
299 if (!verbose_initted)
301 const char *p = _dbus_getenv ("DBUS_VERBOSE");
302 verbose = p != NULL && *p == '1';
303 verbose_initted = TRUE;
308 _dbus_is_verbose_real (void)
310 _dbus_verbose_init ();
315 * Prints a warning message to stderr
316 * if the user has enabled verbose mode.
317 * This is the real function implementation,
318 * use _dbus_verbose() macro in code.
320 * @param format printf-style format string.
323 _dbus_verbose_real (const char *format,
327 static dbus_bool_t need_pid = TRUE;
330 /* things are written a bit oddly here so that
331 * in the non-verbose case we just have the one
332 * conditional and return immediately.
334 if (!_dbus_is_verbose_real())
337 /* Print out pid before the line */
340 #if PTHREAD_IN_VERBOSE
341 fprintf (stderr, "%lu: 0x%lx: ", _dbus_getpid (), pthread_self ());
343 fprintf (stderr, "%lu: ", _dbus_getpid ());
348 /* Only print pid again if the next line is a new line */
349 len = strlen (format);
350 if (format[len-1] == '\n')
355 va_start (args, format);
356 vfprintf (stderr, format, args);
363 * Reinitializes the verbose logging code, used
364 * as a hack in dbus-spawn.c so that a child
365 * process re-reads its pid
369 _dbus_verbose_reset_real (void)
371 verbose_initted = FALSE;
374 #endif /* DBUS_ENABLE_VERBOSE_MODE */
377 * Duplicates a string. Result must be freed with
378 * dbus_free(). Returns #NULL if memory allocation fails.
379 * If the string to be duplicated is #NULL, returns #NULL.
381 * @param str string to duplicate.
382 * @returns newly-allocated copy.
385 _dbus_strdup (const char *str)
395 copy = dbus_malloc (len + 1);
399 memcpy (copy, str, len + 1);
405 * Duplicates a block of memory. Returns
408 * @param mem memory to copy
409 * @param n_bytes number of bytes to copy
413 _dbus_memdup (const void *mem,
418 copy = dbus_malloc (n_bytes);
422 memcpy (copy, mem, n_bytes);
428 * Duplicates a string array. Result may be freed with
429 * dbus_free_string_array(). Returns #NULL if memory allocation fails.
430 * If the array to be duplicated is #NULL, returns #NULL.
432 * @param array array to duplicate.
433 * @returns newly-allocated copy.
436 _dbus_dup_string_array (const char **array)
445 for (len = 0; array[len] != NULL; ++len)
448 copy = dbus_new0 (char*, len + 1);
455 copy[i] = _dbus_strdup (array[i]);
458 dbus_free_string_array (copy);
469 * Checks whether a string array contains the given string.
471 * @param array array to search.
472 * @param str string to look for
473 * @returns #TRUE if array contains string
476 _dbus_string_array_contains (const char **array,
482 while (array[i] != NULL)
484 if (strcmp (array[i], str) == 0)
493 * Generates a new UUID. If you change how this is done,
494 * there's some text about it in the spec that should also change.
496 * @param uuid the uuid to initialize
499 _dbus_generate_uuid (DBusGUID *uuid)
505 _dbus_get_current_time (&now, NULL);
507 uuid->as_uint32s[0] = now;
509 ts_size = sizeof (uuid->as_uint32s[0]);
510 p = ((char*)uuid->as_bytes) + ts_size;
512 _dbus_generate_random_bytes_buffer (p,
513 sizeof (uuid->as_bytes) - ts_size);
519 * @param uuid the uuid
520 * @param encoded string to append hex uuid to
521 * @returns #FALSE if no memory
524 _dbus_uuid_encode (const DBusGUID *uuid,
528 _dbus_string_init_const_len (&binary, uuid->as_bytes, DBUS_UUID_LENGTH_BYTES);
529 return _dbus_string_hex_encode (&binary, 0, encoded, _dbus_string_get_length (encoded));
533 _dbus_read_uuid_file_without_creating (const DBusString *filename,
541 _dbus_string_init (&contents);
542 _dbus_string_init (&decoded);
544 if (!_dbus_file_get_contents (&contents, filename, error))
547 _dbus_string_chop_white (&contents);
549 if (_dbus_string_get_length (&contents) != DBUS_UUID_LENGTH_HEX)
551 dbus_set_error (error, DBUS_ERROR_INVALID_FILE_CONTENT,
552 "UUID file '%s' should contain a hex string of length %d, not length %d, with no other text",
553 _dbus_string_get_const_data (filename),
554 DBUS_UUID_LENGTH_HEX,
555 _dbus_string_get_length (&contents));
559 if (!_dbus_string_hex_decode (&contents, 0, &end, &decoded, 0))
561 _DBUS_SET_OOM (error);
567 dbus_set_error (error, DBUS_ERROR_INVALID_FILE_CONTENT,
568 "UUID file '%s' contains invalid hex data",
569 _dbus_string_get_const_data (filename));
573 if (_dbus_string_get_length (&decoded) != DBUS_UUID_LENGTH_BYTES)
575 dbus_set_error (error, DBUS_ERROR_INVALID_FILE_CONTENT,
576 "UUID file '%s' contains %d bytes of hex-encoded data instead of %d",
577 _dbus_string_get_const_data (filename),
578 _dbus_string_get_length (&decoded),
579 DBUS_UUID_LENGTH_BYTES);
583 _dbus_string_copy_to_buffer (&decoded, uuid->as_bytes, DBUS_UUID_LENGTH_BYTES);
585 _dbus_string_free (&decoded);
586 _dbus_string_free (&contents);
588 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
593 _DBUS_ASSERT_ERROR_IS_SET (error);
594 _dbus_string_free (&contents);
595 _dbus_string_free (&decoded);
600 _dbus_create_uuid_file_exclusively (const DBusString *filename,
606 _dbus_string_init (&encoded);
608 _dbus_generate_uuid (uuid);
610 if (!_dbus_uuid_encode (uuid, &encoded))
612 _DBUS_SET_OOM (error);
616 /* FIXME this is racy; we need a save_file_exclusively
617 * function. But in practice this should be fine for now.
619 * - first be sure we can create the file and it
620 * doesn't exist by creating it empty with O_EXCL
621 * - then create it by creating a temporary file and
622 * overwriting atomically with rename()
624 if (!_dbus_create_file_exclusively (filename, error))
627 if (!_dbus_string_append_byte (&encoded, '\n'))
629 _DBUS_SET_OOM (error);
633 if (!_dbus_string_save_to_file (&encoded, filename, error))
637 _dbus_string_free (&encoded);
639 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
643 _DBUS_ASSERT_ERROR_IS_SET (error);
644 _dbus_string_free (&encoded);
649 * Reads (and optionally writes) a uuid to a file. Initializes the uuid
650 * unless an error is returned.
652 * @param filename the name of the file
653 * @param uuid uuid to be initialized with the loaded uuid
654 * @param create_if_not_found #TRUE to create a new uuid and save it if the file doesn't exist
655 * @param error the error return
656 * @returns #FALSE if the error is set
659 _dbus_read_uuid_file (const DBusString *filename,
661 dbus_bool_t create_if_not_found,
664 DBusError read_error;
666 dbus_error_init (&read_error);
668 if (_dbus_read_uuid_file_without_creating (filename, uuid, &read_error))
671 if (!create_if_not_found)
673 dbus_move_error (&read_error, error);
677 /* If the file exists and contains junk, we want to keep that error
678 * message instead of overwriting it with a "file exists" error
679 * message when we try to write
681 if (dbus_error_has_name (&read_error, DBUS_ERROR_INVALID_FILE_CONTENT))
683 dbus_move_error (&read_error, error);
688 dbus_error_free (&read_error);
689 return _dbus_create_uuid_file_exclusively (filename, uuid, error);
693 _DBUS_DEFINE_GLOBAL_LOCK (machine_uuid);
694 static int machine_uuid_initialized_generation = 0;
695 static DBusGUID machine_uuid;
698 * Gets the hex-encoded UUID of the machine this function is
699 * executed on. This UUID is guaranteed to be the same for a given
700 * machine at least until it next reboots, though it also
701 * makes some effort to be the same forever, it may change if the
702 * machine is reconfigured or its hardware is modified.
704 * @param uuid_str string to append hex-encoded machine uuid to
705 * @returns #FALSE if no memory
708 _dbus_get_local_machine_uuid_encoded (DBusString *uuid_str)
712 _DBUS_LOCK (machine_uuid);
713 if (machine_uuid_initialized_generation != _dbus_current_generation)
716 dbus_error_init (&error);
717 if (!_dbus_read_local_machine_uuid (&machine_uuid, FALSE,
720 #ifndef DBUS_BUILD_TESTS
721 /* For the test suite, we may not be installed so just continue silently
722 * here. But in a production build, we want to be nice and loud about
725 _dbus_warn_check_failed ("D-Bus library appears to be incorrectly set up; failed to read machine uuid: %s\n"
726 "See the manual page for dbus-uuidgen to correct this issue.\n",
730 dbus_error_free (&error);
732 _dbus_generate_uuid (&machine_uuid);
736 ok = _dbus_uuid_encode (&machine_uuid, uuid_str);
738 _DBUS_UNLOCK (machine_uuid);
743 #ifdef DBUS_BUILD_TESTS
745 * Returns a string describing the given name.
747 * @param header_field the field to describe
748 * @returns a constant string describing the field
751 _dbus_header_field_to_string (int header_field)
753 switch (header_field)
755 case DBUS_HEADER_FIELD_INVALID:
757 case DBUS_HEADER_FIELD_PATH:
759 case DBUS_HEADER_FIELD_INTERFACE:
761 case DBUS_HEADER_FIELD_MEMBER:
763 case DBUS_HEADER_FIELD_ERROR_NAME:
765 case DBUS_HEADER_FIELD_REPLY_SERIAL:
766 return "reply-serial";
767 case DBUS_HEADER_FIELD_DESTINATION:
768 return "destination";
769 case DBUS_HEADER_FIELD_SENDER:
771 case DBUS_HEADER_FIELD_SIGNATURE:
777 #endif /* DBUS_BUILD_TESTS */
779 #ifndef DBUS_DISABLE_CHECKS
780 /** String used in _dbus_return_if_fail macro */
781 const char _dbus_return_if_fail_warning_format[] =
782 "arguments to %s() were incorrect, assertion \"%s\" failed in file %s line %d.\n"
783 "This is normally a bug in some application using the D-Bus library.\n";
786 #ifndef DBUS_DISABLE_ASSERT
788 * Internals of _dbus_assert(); it's a function
789 * rather than a macro with the inline code so
790 * that the assertion failure blocks don't show up
791 * in test suite coverage, and to shrink code size.
793 * @param condition TRUE if assertion succeeded
794 * @param condition_text condition as a string
795 * @param file file the assertion is in
796 * @param line line the assertion is in
797 * @param func function the assertion is in
800 _dbus_real_assert (dbus_bool_t condition,
801 const char *condition_text,
806 if (_DBUS_UNLIKELY (!condition))
808 _dbus_warn ("%lu: assertion failed \"%s\" file \"%s\" line %d function %s\n",
809 _dbus_getpid (), condition_text, file, line, func);
815 * Internals of _dbus_assert_not_reached(); it's a function
816 * rather than a macro with the inline code so
817 * that the assertion failure blocks don't show up
818 * in test suite coverage, and to shrink code size.
820 * @param explanation what was reached that shouldn't have been
821 * @param file file the assertion is in
822 * @param line line the assertion is in
825 _dbus_real_assert_not_reached (const char *explanation,
829 _dbus_warn ("File \"%s\" line %d process %lu should not have been reached: %s\n",
830 file, line, _dbus_getpid (), explanation);
833 #endif /* DBUS_DISABLE_ASSERT */
835 #ifdef DBUS_BUILD_TESTS
837 run_failing_each_malloc (int n_mallocs,
838 const char *description,
839 DBusTestMemoryFunction func,
842 n_mallocs += 10; /* fudge factor to ensure reallocs etc. are covered */
844 while (n_mallocs >= 0)
846 _dbus_set_fail_alloc_counter (n_mallocs);
848 _dbus_verbose ("\n===\n%s: (will fail malloc %d with %d failures)\n===\n",
849 description, n_mallocs,
850 _dbus_get_fail_alloc_failures ());
852 if (!(* func) (data))
858 _dbus_set_fail_alloc_counter (_DBUS_INT_MAX);
864 * Tests how well the given function responds to out-of-memory
865 * situations. Calls the function repeatedly, failing a different
866 * call to malloc() each time. If the function ever returns #FALSE,
867 * the test fails. The function should return #TRUE whenever something
868 * valid (such as returning an error, or succeeding) occurs, and #FALSE
869 * if it gets confused in some way.
871 * @param description description of the test used in verbose output
872 * @param func function to call
873 * @param data data to pass to function
874 * @returns #TRUE if the function never returns FALSE
877 _dbus_test_oom_handling (const char *description,
878 DBusTestMemoryFunction func,
883 int max_failures_to_try;
886 /* Run once to see about how many mallocs are involved */
888 _dbus_set_fail_alloc_counter (_DBUS_INT_MAX);
890 _dbus_verbose ("Running once to count mallocs\n");
892 if (!(* func) (data))
895 approx_mallocs = _DBUS_INT_MAX - _dbus_get_fail_alloc_counter ();
897 _dbus_verbose ("\n=================\n%s: about %d mallocs total\n=================\n",
898 description, approx_mallocs);
900 setting = _dbus_getenv ("DBUS_TEST_MALLOC_FAILURES");
905 _dbus_string_init_const (&str, setting);
907 if (!_dbus_string_parse_int (&str, 0, &v, NULL))
908 _dbus_warn ("couldn't parse '%s' as integer\n", setting);
909 max_failures_to_try = v;
913 max_failures_to_try = 4;
916 i = setting ? max_failures_to_try - 1 : 1;
917 while (i < max_failures_to_try)
919 _dbus_set_fail_alloc_failures (i);
920 if (!run_failing_each_malloc (approx_mallocs, description, func, data))
925 _dbus_verbose ("\n=================\n%s: all iterations passed\n=================\n",
930 #endif /* DBUS_BUILD_TESTS */