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1 /* -*- mode: C; c-file-style: "gnu" -*- */
2 /* dbus-sysdeps.h Wrappers around system/libc features (internal to D-Bus implementation)
3  *
4  * Copyright (C) 2002, 2003  Red Hat, Inc.
5  * Copyright (C) 2003 CodeFactory AB
6  *
7  * Licensed under the Academic Free License version 2.1
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program; if not, write to the Free Software
21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
22  *
23  */
24 
25 #ifndef DBUS_SYSDEPS_H
26 #define DBUS_SYSDEPS_H
27 
28 #include <config.h>
29 
30 #include <dbus/dbus-errors.h>
31 
32 /* this is perhaps bogus, but strcmp() etc. are faster if we use the
33  * stuff straight out of string.h, so have this here for now.
34  */
35 #include <string.h>
36 
37 /* and it would just be annoying to abstract this */
38 #include <errno.h>
39 
40 #include <stdarg.h>
41 
42 DBUS_BEGIN_DECLS
43 
44 /* Forward declarations */
45 
46 /** An opaque string type */
47 typedef struct DBusString DBusString;
48 
49 /** An opaque list type */
50 typedef struct DBusList DBusList;
51 
52 /**
53  * @addtogroup DBusSysdeps
54  *
55  * @{
56  */
57 
58 /* The idea of this file is to encapsulate everywhere that we're
59  * relying on external libc features, for ease of security
60  * auditing. The idea is from vsftpd. This also gives us a chance to
61  * make things more convenient to use, e.g.  by reading into a
62  * DBusString. Operating system headers aren't intended to be used
63  * outside of this file and a limited number of others (such as
64  * dbus-memory.c)
65  */
66 
67 #if     __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ > 4)
68 #define _DBUS_GNUC_PRINTF( format_idx, arg_idx )    \
69   __attribute__((__format__ (__printf__, format_idx, arg_idx)))
70 #define _DBUS_GNUC_NORETURN                         \
71   __attribute__((__noreturn__))
72 #else   /* !__GNUC__ */
73 #define _DBUS_GNUC_PRINTF( format_idx, arg_idx )
74 #define _DBUS_GNUC_NORETURN
75 #endif  /* !__GNUC__ */
76 
77 /** @def _DBUS_GNUC_PRINTF
78  * used to tell gcc about printf format strings
79  */
80 /** @def _DBUS_GNUC_NORETURN
81  * used to tell gcc about functions that never return, such as _dbus_abort()
82  */
83 
84 void _dbus_abort (void) _DBUS_GNUC_NORETURN;
85 
86 const char* _dbus_getenv (const char *varname);
87 dbus_bool_t _dbus_setenv (const char *varname,
88 			  const char *value);
89 
90 /** A process ID */
91 typedef unsigned long dbus_pid_t;
92 /** A user ID */
93 typedef unsigned long dbus_uid_t;
94 /** A group ID */
95 typedef unsigned long dbus_gid_t;
96 
97 /** an invalid PID used to represent an uninitialized dbus_pid_t field */
98 #define DBUS_PID_UNSET ((dbus_pid_t) -1)
99 /** an invalid UID used to represent an uninitialized dbus_uid_t field */
100 #define DBUS_UID_UNSET ((dbus_uid_t) -1)
101 /** an invalid GID used to represent an uninitialized dbus_gid_t field */
102 #define DBUS_GID_UNSET ((dbus_gid_t) -1)
103 
104 /** an appropriate printf format for dbus_pid_t */
105 #define DBUS_PID_FORMAT "%lu"
106 /** an appropriate printf format for dbus_uid_t */
107 #define DBUS_UID_FORMAT "%lu"
108 /** an appropriate printf format for dbus_gid_t */
109 #define DBUS_GID_FORMAT "%lu"
110 
111 
112 /**
113  * Socket interface
114  *
115  *  @todo Use for the file descriptors a struct
116  *           - struct DBusSocket{ int d; }; -
117  *        instead of int to get type-safety which
118  *        will be checked by the compiler.
119  *
120  */
121 
122 dbus_bool_t _dbus_open_tcp_socket  (int              *fd,
123                                     DBusError        *error);
124 dbus_bool_t _dbus_close_socket     (int               fd,
125                                     DBusError        *error);
126 int         _dbus_read_socket      (int               fd,
127                                     DBusString       *buffer,
128                                     int               count);
129 int         _dbus_write_socket     (int               fd,
130                                     const DBusString *buffer,
131                                     int               start,
132                                     int               len);
133 int         _dbus_write_socket_two (int               fd,
134                                     const DBusString *buffer1,
135                                     int               start1,
136                                     int               len1,
137                                     const DBusString *buffer2,
138                                     int               start2,
139                                     int               len2);
140 int _dbus_connect_tcp_socket  (const char     *host,
141                                dbus_uint32_t   port,
142                                DBusError      *error);
143 int _dbus_listen_tcp_socket   (const char     *host,
144                                dbus_uint32_t   port,
145                                DBusError      *error);
146 int _dbus_accept              (int             listen_fd);
147 
148 /**
149  * Struct representing socket credentials
150  */
151 typedef struct
152 {
153   dbus_pid_t pid; /**< process ID or DBUS_PID_UNSET */
154   dbus_uid_t uid; /**< user ID or DBUS_UID_UNSET */
155   dbus_gid_t gid; /**< group ID or DBUS_GID_UNSET */
156 } DBusCredentials;
157 
158 /* FIXME these read/send credentials should get moved to sysdeps-unix.h,
159  * or renamed to reflect what they mean cross-platform
160  */
161 dbus_bool_t _dbus_read_credentials_unix_socket (int              client_fd,
162                                                 DBusCredentials *credentials,
163                                                 DBusError       *error);
164 dbus_bool_t _dbus_send_credentials_unix_socket (int              server_fd,
165                                                 DBusError       *error);
166 
167 
168 void        _dbus_credentials_clear                (DBusCredentials       *credentials);
169 void        _dbus_credentials_from_current_process (DBusCredentials       *credentials);
170 dbus_bool_t _dbus_credentials_match                (const DBusCredentials *expected_credentials,
171                                                     const DBusCredentials *provided_credentials);
172 
173 
174 /** Information about a UNIX user */
175 typedef struct DBusUserInfo  DBusUserInfo;
176 /** Information about a UNIX group */
177 typedef struct DBusGroupInfo DBusGroupInfo;
178 
179 /**
180  * Information about a UNIX user
181  */
182 struct DBusUserInfo
183 {
184   dbus_uid_t  uid;            /**< UID */
185   dbus_gid_t  primary_gid;    /**< GID */
186   dbus_gid_t *group_ids;      /**< Groups IDs, *including* above primary group */
187   int         n_group_ids;    /**< Size of group IDs array */
188   char       *username;       /**< Username */
189   char       *homedir;        /**< Home directory */
190 };
191 
192 /**
193  * Information about a UNIX group
194  */
195 struct DBusGroupInfo
196 {
197   dbus_gid_t  gid;            /**< GID */
198   char       *groupname;      /**< Group name */
199 };
200 
201 dbus_bool_t _dbus_user_info_fill     (DBusUserInfo     *info,
202                                       const DBusString *username,
203                                       DBusError        *error);
204 dbus_bool_t _dbus_user_info_fill_uid (DBusUserInfo     *info,
205                                       dbus_uid_t        uid,
206                                       DBusError        *error);
207 void        _dbus_user_info_free     (DBusUserInfo     *info);
208 
209 dbus_bool_t _dbus_group_info_fill     (DBusGroupInfo    *info,
210                                        const DBusString *groupname,
211                                        DBusError        *error);
212 dbus_bool_t _dbus_group_info_fill_gid (DBusGroupInfo    *info,
213                                        dbus_gid_t        gid,
214                                        DBusError        *error);
215 void        _dbus_group_info_free     (DBusGroupInfo    *info);
216 
217 
218 unsigned long _dbus_getpid (void);
219 dbus_uid_t    _dbus_getuid (void);
220 dbus_gid_t    _dbus_getgid (void);
221 
222 /** Opaque type representing an atomically-modifiable integer
223  * that can be used from multiple threads.
224  */
225 typedef struct DBusAtomic DBusAtomic;
226 
227 /**
228  * An atomic integer safe to increment or decrement from multiple threads.
229  */
230 struct DBusAtomic
231 {
232   volatile dbus_int32_t value; /**< Value of the atomic integer. */
233 };
234 
235 dbus_int32_t _dbus_atomic_inc (DBusAtomic *atomic);
236 dbus_int32_t _dbus_atomic_dec (DBusAtomic *atomic);
237 
238 /** There is data to read */
239 #define _DBUS_POLLIN      0x0001
240 /** There is urgent data to read */
241 #define _DBUS_POLLPRI     0x0002
242 /** Writing now will not block */
243 #define _DBUS_POLLOUT     0x0004
244 /** Error condition */
245 #define _DBUS_POLLERR     0x0008
246 /** Hung up */
247 #define _DBUS_POLLHUP     0x0010
248 /** Invalid request: fd not open */
249 #define _DBUS_POLLNVAL    0x0020
250 
251 /**
252  * A portable struct pollfd wrapper.
253  */
254 typedef struct
255 {
256   int fd;            /**< File descriptor */
257   short events;      /**< Events to poll for */
258   short revents;     /**< Events that occurred */
259 } DBusPollFD;
260 
261 int _dbus_poll (DBusPollFD *fds,
262                 int         n_fds,
263                 int         timeout_milliseconds);
264 
265 void _dbus_sleep_milliseconds (int milliseconds);
266 
267 void _dbus_get_current_time (long *tv_sec,
268                              long *tv_usec);
269 
270 /**
271  * File/directory interface
272  */
273 dbus_bool_t _dbus_file_exists         (const char       *file);
274 dbus_bool_t _dbus_file_get_contents   (DBusString       *str,
275                                        const DBusString *filename,
276                                        DBusError        *error);
277 dbus_bool_t _dbus_string_save_to_file (const DBusString *str,
278                                        const DBusString *filename,
279                                        DBusError        *error);
280 
281 dbus_bool_t _dbus_make_file_world_readable   (const DBusString *filename,
282                                               DBusError *error);
283 
284 dbus_bool_t    _dbus_create_file_exclusively (const DBusString *filename,
285                                               DBusError        *error);
286 dbus_bool_t    _dbus_delete_file             (const DBusString *filename,
287                                               DBusError        *error);
288 dbus_bool_t    _dbus_create_directory        (const DBusString *filename,
289                                               DBusError        *error);
290 dbus_bool_t    _dbus_delete_directory        (const DBusString *filename,
291 					      DBusError        *error);
292 
293 dbus_bool_t _dbus_concat_dir_and_file (DBusString       *dir,
294                                        const DBusString *next_component);
295 dbus_bool_t _dbus_string_get_dirname  (const DBusString *filename,
296                                        DBusString       *dirname);
297 dbus_bool_t _dbus_path_is_absolute    (const DBusString *filename);
298 
299 dbus_bool_t _dbus_get_standard_session_servicedirs (DBusList **dirs);
300 
301 /** Opaque type for reading a directory listing */
302 typedef struct DBusDirIter DBusDirIter;
303 
304 DBusDirIter* _dbus_directory_open          (const DBusString *filename,
305                                             DBusError        *error);
306 dbus_bool_t  _dbus_directory_get_next_file (DBusDirIter      *iter,
307                                             DBusString       *filename,
308                                             DBusError        *error);
309 void         _dbus_directory_close         (DBusDirIter      *iter);
310 
311 dbus_bool_t  _dbus_check_dir_is_private_to_user    (DBusString *dir,
312                                                     DBusError *error);
313 
314 void _dbus_fd_set_close_on_exec (int fd);
315 
316 const char* _dbus_get_tmpdir      (void);
317 
318 /**
319  * Random numbers
320  */
321 void        _dbus_generate_pseudorandom_bytes_buffer (char *buffer,
322                                                       int   n_bytes);
323 void        _dbus_generate_random_bytes_buffer (char       *buffer,
324                                                 int         n_bytes);
325 dbus_bool_t _dbus_generate_random_bytes        (DBusString *str,
326                                                 int         n_bytes);
327 dbus_bool_t _dbus_generate_random_ascii        (DBusString *str,
328                                                 int         n_bytes);
329 
330 const char* _dbus_error_from_errno (int error_number);
331 
332 void _dbus_disable_sigpipe (void);
333 
334 
335 void _dbus_exit (int code) _DBUS_GNUC_NORETURN;
336 
337 int _dbus_printf_string_upper_bound (const char *format,
338                                      va_list args);
339 
340 
341 /**
342  * Portable struct with stat() results
343  */
344 typedef struct
345 {
346   unsigned long mode;  /**< File mode */
347   unsigned long nlink; /**< Number of hard links */
348   dbus_uid_t    uid;   /**< User owning file */
349   dbus_gid_t    gid;   /**< Group owning file */
350   unsigned long size;  /**< Size of file */
351   unsigned long atime; /**< Access time */
352   unsigned long mtime; /**< Modify time */
353   unsigned long ctime; /**< Creation time */
354 } DBusStat;
355 
356 dbus_bool_t _dbus_stat             (const DBusString *filename,
357                                     DBusStat         *statbuf,
358                                     DBusError        *error);
359 dbus_bool_t _dbus_full_duplex_pipe (int              *fd1,
360                                     int              *fd2,
361                                     dbus_bool_t       blocking,
362                                     DBusError        *error);
363 
364 void        _dbus_print_backtrace  (void);
365 
366 dbus_bool_t _dbus_become_daemon   (const DBusString *pidfile,
367 				   int               print_pid_fd,
368                                    DBusError        *error);
369 dbus_bool_t _dbus_write_pid_file  (const DBusString *filename,
370                                    unsigned long     pid,
371                                    DBusError        *error);
372 dbus_bool_t _dbus_change_identity (unsigned long     uid,
373                                    unsigned long     gid,
374                                    DBusError        *error);
375 
376 /** A UNIX signal handler */
377 typedef void (* DBusSignalHandler) (int sig);
378 
379 void _dbus_set_signal_handler (int               sig,
380                                DBusSignalHandler handler);
381 
382 dbus_bool_t _dbus_user_at_console (const char *username,
383                                    DBusError  *error);
384 
385 /* Define DBUS_VA_COPY() to do the right thing for copying va_list variables.
386  * config.h may have already defined DBUS_VA_COPY as va_copy or __va_copy.
387  */
388 #if !defined (DBUS_VA_COPY)
389 #  if defined (__GNUC__) && defined (__PPC__) && (defined (_CALL_SYSV) || defined (_WIN32))
390 #    define DBUS_VA_COPY(ap1, ap2)   (*(ap1) = *(ap2))
391 #  elif defined (DBUS_VA_COPY_AS_ARRAY)
392 #    define DBUS_VA_COPY(ap1, ap2)   memcpy ((ap1), (ap2), sizeof (va_list))
393 #  else /* va_list is a pointer */
394 #    define DBUS_VA_COPY(ap1, ap2)   ((ap1) = (ap2))
395 #  endif /* va_list is a pointer */
396 #endif /* !DBUS_VA_COPY */
397 
398 
399 /**
400  * Casts a primitive C type to a byte array and then indexes
401  * a particular byte of the array.
402  */
403 #define _DBUS_BYTE_OF_PRIMITIVE(p, i) \
404     (((const char*)&(p))[(i)])
405 /** On x86 there is an 80-bit FPU, and if you do "a == b" it may have a
406  * or b in an 80-bit register, thus failing to compare the two 64-bit
407  * doubles for bitwise equality. So this macro compares the two doubles
408  * bitwise.
409  */
410 #define _DBUS_DOUBLES_BITWISE_EQUAL(a, b)                                       \
411      (_DBUS_BYTE_OF_PRIMITIVE (a, 0) == _DBUS_BYTE_OF_PRIMITIVE (b, 0) &&       \
412       _DBUS_BYTE_OF_PRIMITIVE (a, 1) == _DBUS_BYTE_OF_PRIMITIVE (b, 1) &&       \
413       _DBUS_BYTE_OF_PRIMITIVE (a, 2) == _DBUS_BYTE_OF_PRIMITIVE (b, 2) &&       \
414       _DBUS_BYTE_OF_PRIMITIVE (a, 3) == _DBUS_BYTE_OF_PRIMITIVE (b, 3) &&       \
415       _DBUS_BYTE_OF_PRIMITIVE (a, 4) == _DBUS_BYTE_OF_PRIMITIVE (b, 4) &&       \
416       _DBUS_BYTE_OF_PRIMITIVE (a, 5) == _DBUS_BYTE_OF_PRIMITIVE (b, 5) &&       \
417       _DBUS_BYTE_OF_PRIMITIVE (a, 6) == _DBUS_BYTE_OF_PRIMITIVE (b, 6) &&       \
418       _DBUS_BYTE_OF_PRIMITIVE (a, 7) == _DBUS_BYTE_OF_PRIMITIVE (b, 7))
419 
420 dbus_bool_t _dbus_parse_uid (const DBusString  *uid_str,
421                              dbus_uid_t        *uid);
422 
423 dbus_bool_t _dbus_get_autolaunch_address (DBusString *address,
424 					  DBusError *error);
425 
426 /** Type representing a universally unique ID
427  * @todo rename to UUID instead of GUID
428  */
429 typedef union DBusGUID DBusGUID;
430 
431 dbus_bool_t _dbus_read_local_machine_uuid   (DBusGUID         *machine_id,
432                                              dbus_bool_t       create_if_not_found,
433                                              DBusError        *error);
434 
435 /**
436  * Initialize threads as in dbus_threads_init_default(), appropriately
437  * for the platform.
438  * @returns #FALSE if no memory
439  */
440 dbus_bool_t _dbus_threads_init_platform_specific (void);
441 
442 /** @} */
443 
444 DBUS_END_DECLS
445 
446 #endif /* DBUS_SYSDEPS_H */
447