xref: /NextBSD/lib/libasl/asl.h (revision 33da5adc555b3bc29986eeadca03829e4ad06b1e)
1 /*
2  * Copyright (c) 2004-2013 Apple Inc. All rights reserved.
3  *
4  * @APPLE_LICENSE_HEADER_START@
5  *
6  * This file contains Original Code and/or Modifications of Original Code
7  * as defined in and that are subject to the Apple Public Source License
8  * Version 2.0 (the 'License'). You may not use this file except in
9  * compliance with the License. Please obtain a copy of the License at
10  * http://www.opensource.apple.com/apsl/ and read it before using this
11  * file.
12  *
13  * The Original Code and all software distributed under the License are
14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
18  * Please see the License for the specific language governing rights and
19  * limitations under the License.
20  *
21  * @APPLE_LICENSE_HEADER_END@
22  */
23 
24 #ifndef __ASL_H__
25 #define __ASL_H__
26 
27 #include <stdint.h>
28 #include <stddef.h>
29 #include <stdarg.h>
30 #include <sys/cdefs.h>
31 #include <Availability.h>
32 
33 /* Version number encodes the date YYYYMMDD */
34 #define ASL_API_VERSION 20131108
35 
36 typedef struct __asl_object_s *asl_object_t;
37 typedef asl_object_t aslclient;
38 typedef asl_object_t aslmsg;
39 typedef asl_object_t aslresponse;
40 
41 /*! @header
42  * These routines provide an interface to the Apple System Log facility.
43  * The API allows client applications to create flexible, structured messages
44  * and send them to the syslogd server.  Messages received by the server are
45  * saved in a data store, subject to input filtering constraints.
46  * This API also permits clients to create queries and search the message
47  * data store for matching messages.
48  */
49 
50 /*
51  * NOTE FOR HeaderDoc
52  *
53  * These are added to allow headerdoc2html to process
54  * the prototypes of asl_log and asl_vlog correctly.
55  * The "-p" option to headerdoc2html is required.
56  */
57 #ifndef __printflike
58 /*! @parseOnly */
59 #define __printflike(a,b)
60 #endif
61 
62 #pragma mark -
63 
64 /*! @defineblock Log Message Priority Levels
65  * Log levels of the message.
66  */
67 #define ASL_LEVEL_EMERG   0
68 #define ASL_LEVEL_ALERT   1
69 #define ASL_LEVEL_CRIT    2
70 #define ASL_LEVEL_ERR     3
71 #define ASL_LEVEL_WARNING 4
72 #define ASL_LEVEL_NOTICE  5
73 #define ASL_LEVEL_INFO    6
74 #define ASL_LEVEL_DEBUG   7
75 /*! @/defineblock */
76 
77 #pragma mark -
78 
79 /*! @defineblock Log Message Priority Level Strings
80  * Strings corresponding to log levels.
81  */
82 #define ASL_STRING_EMERG	"Emergency"
83 #define ASL_STRING_ALERT	"Alert"
84 #define ASL_STRING_CRIT		"Critical"
85 #define ASL_STRING_ERR		"Error"
86 #define ASL_STRING_WARNING  "Warning"
87 #define ASL_STRING_NOTICE   "Notice"
88 #define ASL_STRING_INFO		"Info"
89 #define ASL_STRING_DEBUG	"Debug"
90 /*! @/defineblock */
91 
92 #pragma mark -
93 
94 /*! @defineblock Attribute Matching
95  * Attribute value comparison operations.
96  */
97 #define ASL_QUERY_OP_CASEFOLD      0x0010
98 #define ASL_QUERY_OP_PREFIX		   0x0020
99 #define ASL_QUERY_OP_SUFFIX		   0x0040
100 #define ASL_QUERY_OP_SUBSTRING     0x0060
101 #define ASL_QUERY_OP_NUMERIC       0x0080
102 #define ASL_QUERY_OP_REGEX         0x0100
103 
104 #define ASL_QUERY_OP_EQUAL         0x0001
105 #define ASL_QUERY_OP_GREATER       0x0002
106 #define ASL_QUERY_OP_GREATER_EQUAL 0x0003
107 #define ASL_QUERY_OP_LESS          0x0004
108 #define ASL_QUERY_OP_LESS_EQUAL    0x0005
109 #define ASL_QUERY_OP_NOT_EQUAL     0x0006
110 #define ASL_QUERY_OP_TRUE          0x0007
111 /*! @/defineblock */
112 
113 #pragma mark -
114 
115 /*! @defineblock Message Attributes
116  * These attributes are known by ASL, and are generally
117  * associated with all log messages.
118  * Additional attributes may be added as desired.
119  */
120 #define ASL_KEY_TIME               "Time"                 /* Timestamp.  Set automatically */
121 #define ASL_KEY_TIME_NSEC          "TimeNanoSec"          /* Nanosecond time. */
122 #define ASL_KEY_HOST               "Host"                 /* Sender's address (set by the server). */
123 #define ASL_KEY_SENDER             "Sender"               /* Sender's identification string.  Default is process name. */
124 #define ASL_KEY_FACILITY           "Facility"             /* Sender's facility.  Default is "user". */
125 #define ASL_KEY_PID                "PID"                  /* Sending process ID encoded as a string.  Set automatically. */
126 #define ASL_KEY_UID                "UID"                  /* UID that sent the log message (set by the server). */
127 #define ASL_KEY_GID                "GID"                  /* GID that sent the log message (set by the server). */
128 #define ASL_KEY_LEVEL              "Level"                /* Log level number encoded as a string.  See levels above. */
129 #define ASL_KEY_MSG                "Message"              /* Message text. */
130 #define ASL_KEY_READ_UID           "ReadUID"              /* User read access (-1 is any user). */
131 #define ASL_KEY_READ_GID           "ReadGID"              /* Group read access (-1 is any group). */
132 #define ASL_KEY_EXPIRE_TIME        "ASLExpireTime"        /* Expiration time for messages with long TTL. */
133 #define ASL_KEY_MSG_ID             "ASLMessageID"         /* 64-bit message ID number (set by the server). */
134 #define ASL_KEY_SESSION            "Session"              /* Session (set by the launchd). */
135 #define ASL_KEY_REF_PID            "RefPID"               /* Reference PID for messages proxied by launchd */
136 #define ASL_KEY_REF_PROC           "RefProc"              /* Reference process for messages proxied by launchd */
137 #define ASL_KEY_AUX_TITLE          "ASLAuxTitle"          /* Auxiliary title string */
138 #define ASL_KEY_AUX_UTI            "ASLAuxUTI"            /* Auxiliary Uniform Type ID */
139 #define ASL_KEY_AUX_URL            "ASLAuxURL"            /* Auxiliary Uniform Resource Locator */
140 #define ASL_KEY_AUX_DATA           "ASLAuxData"           /* Auxiliary in-line data */
141 #define ASL_KEY_OPTION             "ASLOption"            /* Internal */
142 #define ASL_KEY_MODULE             "ASLModule"            /* Internal */
143 #define ASL_KEY_SENDER_INSTANCE	   "SenderInstance"       /* Sender instance UUID. */
144 #define ASL_KEY_SENDER_MACH_UUID   "SenderMachUUID"       /* Sender Mach-O UUID. */
145 #define ASL_KEY_FINAL_NOTIFICATION "ASLFinalNotification" /* syslogd posts value as a notification when message has been processed */
146 #define ASL_KEY_OS_ACTIVITY_ID     "OSActivityID"         /* Current OS Activity for the logging thread */
147 /*! @/defineblock */
148 
149 #pragma mark -
150 
151 /*! @defineblock ASL Object Types
152  * The library uses only one opaque type - asl_object_t.
153  * Many of the routines can operate on several different types.
154  * For example, asl_search() can be used to search a list of messages,
155  * an ASL database directory or data file, or the main ASL database.
156  * It can even be used to check a single message against a query
157  * message, or against another message to check for exact match.
158  *
159  * The first three types are container objects - messages, queries,
160  * and lists of messages or queries.  The following types are
161  * abstractions for ASL data files and ASL data stores (directories
162  * containing data files).
163  *
164  * ASL_TYPE_CLIENT is a high-level object that abstracts ASL
165  * interactions.  It may access ASL stores or files directly,
166  * and it may communicate with ASL daemons.
167  *
168  */
169 #define ASL_TYPE_UNDEF  0xffffffff
170 #define ASL_TYPE_MSG    0
171 #define ASL_TYPE_QUERY  1
172 #define ASL_TYPE_LIST   2
173 #define ASL_TYPE_FILE   3
174 #define ASL_TYPE_STORE  4
175 #define ASL_TYPE_CLIENT 5
176 /*! @/defineblock */
177 
178 #pragma mark -
179 
180 /*! @defineblock search directions
181  * Used for asl_store_match(), asl_file_match(), and asl_match().
182  */
183 #define ASL_MATCH_DIRECTION_FORWARD	1
184 #define ASL_MATCH_DIRECTION_REVERSE	-1
185 /*! @/defineblock */
186 
187 #pragma mark -
188 
189 /*! @defineblock Filter Masks
190  * Used in client-side filtering, which determines which
191  * messages are sent by the client to the syslogd server.
192  */
193 #define ASL_FILTER_MASK_EMERG   0x01
194 #define ASL_FILTER_MASK_ALERT   0x02
195 #define ASL_FILTER_MASK_CRIT    0x04
196 #define ASL_FILTER_MASK_ERR     0x08
197 #define ASL_FILTER_MASK_WARNING 0x10
198 #define ASL_FILTER_MASK_NOTICE  0x20
199 #define ASL_FILTER_MASK_INFO    0x40
200 #define ASL_FILTER_MASK_DEBUG   0x80
201 /*! @/defineblock */
202 
203 #pragma mark -
204 
205 /*! @defineblock Filter Mask Macros
206  * Macros to create bitmasks for filter settings - see asl_set_filter().
207  */
208 #define	ASL_FILTER_MASK(level) (1 << (level))
209 #define	ASL_FILTER_MASK_UPTO(level) ((1 << ((level) + 1)) - 1)
210 /*! @/defineblock */
211 
212 #pragma mark -
213 
214 /*! @defineblock Client Creation Options
215  * Options for asl_open().
216  * Note that ASL_OPT_NO_DELAY no longer has any effect.
217  */
218 #define ASL_OPT_STDERR		0x00000001
219 #define ASL_OPT_NO_DELAY    0x00000002
220 #define ASL_OPT_NO_REMOTE   0x00000004
221 /*! @/defineblock */
222 
223 #pragma mark -
224 
225 /*! @defineblock File and Store Open Options
226  * Options for asl_open_path().
227  */
228 #define ASL_OPT_OPEN_WRITE   0x00000001
229 #define ASL_OPT_CREATE_STORE 0x00000002
230 /*! @/defineblock */
231 
232 #pragma mark -
233 
234 /*! @defineblock File Descriptor Types
235  * Instructions on how to treat the file descriptor in asl_log_descriptor().
236  */
237 #define ASL_LOG_DESCRIPTOR_READ  1
238 #define ASL_LOG_DESCRIPTOR_WRITE 2
239 
240 #pragma mark -
241 
242 /*! @defineblock Output file message and time formats.
243  * These select internally defined formats for printed log messages for
244  * asl_add_output_file().  Custom message and time formats may also be
245  * used.  These pre-defined formats and custom formats are described in detail
246  * in the syslog(1) manual page.
247  */
248 #define ASL_MSG_FMT_RAW "raw"
249 #define ASL_MSG_FMT_STD "std"
250 #define ASL_MSG_FMT_BSD "bsd"
251 #define ASL_MSG_FMT_XML "xml"
252 #define ASL_MSG_FMT_MSG "msg"
253 
254 #define ASL_TIME_FMT_SEC "sec"
255 #define ASL_TIME_FMT_UTC "utc"
256 #define ASL_TIME_FMT_LCL "lcl"
257 
258 #pragma mark -
259 
260 /*! @defineblock Text Encoding Types
261  * These are used by the library when formatting messages to be written
262  * to file descriptors associated with an ASL client handle with
263  * asl_add_output_file().  The syslog(1) manual page describes text encoding
264  * in detail.  ASL_ENCODE_ASL corresponds to the "vis" encoding option
265  * described in the syslog(1) manual.  ASL_ENCODE_XML should be used in
266  * combination with ASL_MSG_FMT_XML to ensure that special XML characters
267  * are correctly encoded.
268  */
269 #define ASL_ENCODE_NONE 0
270 #define ASL_ENCODE_SAFE 1
271 #define ASL_ENCODE_ASL  2
272 #define ASL_ENCODE_XML  3
273 
274 #pragma mark -
275 
276 /*!
277  * ASL_PREFILTER_LOG is a macro similar to asl_log(), but it first checks
278  * if the message will simply be ignored due to local filter settings.
279  * This prevents the variable argument list from being evaluated.
280  * Note that the message may still be processed if it will be written
281  * to a file or stderr.
282  *
283  * @param client
284  *    (input) An ASL_TYPE_CLIENT object.
285  * @param msg
286  *    (input) An asl_object_t of type ASL_TYPE_MSG (default attributes will be supplied if msg is NULL).
287  * @param level
288  *    (input) Log level (ASL_LEVEL_DEBUG to ASL_LEVEL_EMERG).
289  * @param format
290  *    (input) A printf() - style format string followed by a list of arguments.
291  */
292 #define ASL_PREFILTER_LOG(client, msg, level, format, ...) \
293 	do { \
294 		asl_object_t _client = (client); \
295 		asl_object_t _msg = (msg); \
296 		uint32_t _asl_eval = _asl_evaluate_send(_client, _msg, (level)); \
297 		if (_asl_eval != 0) _asl_lib_log(_client, _asl_eval, _msg, (format), ## __VA_ARGS__); \
298 	} while (0)
299 
300 #pragma mark -
301 
302 __BEGIN_DECLS
303 
304 /* ASL Library SPI - do not call directly */
305 int _asl_lib_log(asl_object_t client, uint32_t eval, asl_object_t msg, const char *format, ...) __printflike(4, 5);
306 uint32_t _asl_evaluate_send(asl_object_t client, asl_object_t msg, int level);
307 
308 /*!
309  * Initialize a connection to the ASL server.
310  *
311  * This call is optional in many cases.  The library will perform any
312  * necessary initializations on the fly.  A call to asl_open() is required
313  * if optional settings must be made before messages are sent to the server.
314  * These include setting the client filter and managing additional output
315  * file descriptors.  Note that the default setting of the client filter is
316  * ASL_FILTER_MASK_UPTO(ASL_LEVEL_NOTICE), so ASL_LEVEL_DEBUG and ASL_LEVEL_INFO
317  * messages are not sent to the server by default.
318  * A separate client connection is required for multiple threads or
319  * dispatch queues.
320  *
321  * Options (defined above) may be set using the opts parameter. They are:
322  *
323  *   ASL_OPT_STDERR    - adds stderr as an output file descriptor
324  *
325  *   ASL_OPT_NO_REMOTE - disables the remote-control mechanism for adjusting
326  *                       filter levers for processes using e.g. syslog -c ...
327  *
328  * @param ident
329  *    (input) Sender name.
330  * @param facility
331  *    (input) Facility name.
332  * @param opts
333  *    (input) Options (see Client Creation Options).
334  * @result Returns an ASL client handle (asl_object_t of type ASL_TYPE_CLIENT).
335  */
336 asl_object_t asl_open(const char *ident, const char *facility, uint32_t opts) __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);
337 
338 /*!
339  * Open an ASL database or ASL data file for read or write access.
340  *
341  * Opens an ASL database if the path specifies a directory, or
342  * an ASL data file if the path specifies a file. Opens the system
343  * ASL database if path is NULL.
344  *
345  * If the ASL_OPT_OPEN_READ option is specified, the database or data file may be
346  * searched with asl_search() or asl_match(). asl_next() and asl_prev() may be used
347  * to iterate over the messages in the database or file.
348  *
349  * If the ASL_OPT_OPEN_WRITE option is specified, an existing file or database is
350  * opened for writing.  New messages may be added to the file or database using
351  * asl_append(), asl_send(), asl_log(), or asl_vlog().  Existing messages in the
352  * store or file may not be deleted or modified.
353  *
354  * If the path does not exist, asl_open_path() will create a new database if
355  * ASL_OPT_CREATE_STORE is set in the options, or a new data file otherwise.
356  * The file will be created with the user's effective UID and GID as owner and
357  * group.  The mode will be 0644.  If a different mode, UID, or GID is desired,
358  * an empty file or directory may be pre-created with the desired settings.
359  *
360  * @param path
361  *    (input) Location of the ASL database or ASL data file in the filesystem.
362  *    A value of NULL may be used to open the system's database.
363  * @param opts
364  *    (input) Options (see File and Store Open Options).
365  * @result Returns an ASL object of type ASL_TYPE_STORE or ASL_TYPE_FILE, or NULL on failure.
366  */
367 asl_object_t asl_open_path(const char *path, uint32_t opts) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
368 
369 /*!
370  * Shuts down a connection to the server.
371  * This routine is identical to asl_release().
372  *
373  * @param obj
374  *    (input) An ASL object.
375  */
376 void asl_close(asl_object_t obj) __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);
377 
378 /*!
379  * Write log messages to the given file descriptor.
380  *
381  * Log messages will be written to this file as well as to the server.
382  * This is equivalent to calling:
383  * asl_add_output_file(asl, descriptor, ASL_MSG_FMT_STD, ASL_TIME_FMT_LCL, ASL_FILTER_MASK_UPTO(ASL_LEVEL_DEBUG), ASL_ENCODE_SAFE)
384  *
385  * @param client
386  *    (input) An ASL client handle (asl_object_t of type ASL_TYPE_CLIENT).
387  * @param descriptor
388  *    (input) A file descriptor.
389  * @result Returns 0 on success, non-zero on failure.
390 */
391 int asl_add_log_file(asl_object_t client, int descriptor) __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);
392 
393 /*!
394  * Write log messages to the given file descriptor.
395  *
396  * Log messages will be written to this file as well as to the server.
397  * This routine extends the basic interface offered by asl_add_log_file(),
398  * allowing control of the format used to write log message written to the file.
399  * control of the time zone used when printing time values, and allowing
400  * individual filtering control for each log file.
401  *
402  * @param client
403  *    (input) An ASL client handle (asl_object_t of type ASL_TYPE_CLIENT).
404  * @param descriptor
405  *    (input) A file descriptor.
406  * @param mfmt
407  *    (input) A character string specifying the message format.
408  * @param tfmt
409  *    (input) A character string specifying the time format.
410  * @param filter
411  *    (input) A filter value.
412  * @param text_encoding
413  *    (input) A text encoding type.
414  * @result Returns 0 on success, non-zero on failure.
415  */
416 int asl_add_output_file(asl_object_t client, int fd, const char *mfmt, const char *tfmt, int filter, int text_encoding) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
417 
418 /*!
419  * Write log messages to the given file descriptor.
420  *
421  * Sets or changes a filter value for filtering messages written to a file associated
422  * with an ASL client handle using asl_add_output_file() or asl_add_log_file().
423  *
424  * @param client
425  *    (input) An ASL client handle (asl_object_t of type ASL_TYPE_CLIENT).
426  * @param descriptor
427  *    (input) A file descriptor.
428  * @param filter
429  *    (input) A filter value.
430  * @result Returns the previous filter value.
431  */
432 int asl_set_output_file_filter(asl_object_t client, int fd, int filter) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
433 
434 /*!
435  * Stop writing log messages to the given file descriptor.
436  * The file descripter is not closed by this routine.
437  *
438  * @param client
439  *    (input) An ASL client handle (asl_object_t of type ASL_TYPE_CLIENT).
440  * @param descriptor
441  *    (input) A file descriptor.
442  * @result Returns 0 on success, non-zero on failure.
443  */
444 int asl_remove_log_file(asl_object_t client, int descriptor) __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);
445 
446 /*!
447  * Set a filter for messages being sent to the server.
448  * The filter is a bitmask representing priorities.  The ASL_FILTER_MASK
449  * macro may be used to convert a priority level into a bitmask for that
450  * level.  The ASL_FILTER_MASK_UPTO macro creates a bitmask for all
451  * priorities up to and including a given priority.
452  * Messages with priority levels that do not have a corresponding bit
453  * set in the filter are not sent to the server, although they will be
454  * sent to any file descripters added with asl_add_log_file().
455  * The default setting is ASL_FILTER_MASK_UPTO(ASL_LEVEL_NOTICE).
456  * Returns the previous filter value.
457  *
458  * @param client
459  *    (input) An ASL client handle (asl_object_t of type ASL_TYPE_CLIENT).
460  * @param f
461  *    (input) A filter value.
462  * @result Returns the previous filter value.
463  */
464 int asl_set_filter(asl_object_t client, int f) __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);
465 
466 /*
467  * Examine attribute keys.
468  *
469  * @param msg
470  *    (input) An ASL message or query (asl_object_t of type ASL_TYPE_MSG or ASL_TYPE_QUERY).
471  * @param n
472  *    (input) An index value.
473  * @result Returns the key of the nth attribute in a message (beginning at zero),
474  * or NULL if n is greater than the largest message index.
475  */
476 const char *asl_key(asl_object_t msg, uint32_t n) __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);
477 
478 /*
479  * Examine attribute keys.
480  *
481  * @param msg
482  *    (input) An ASL message or query (asl_object_t of type ASL_TYPE_MSG or ASL_TYPE_QUERY).
483  * @param key
484  *    (output) key at the given index.  May be NULL.
485  * @param val
486  *    (output) val at the given index.  May be NULL.
487  * @param op
488  *    (output) op at the given index.  May be NULL.
489  * @param n
490  *    (input) An index value.
491  * @result returns 0 for success, non-zero for failure.
492  */
493 int asl_fetch_key_val_op(asl_object_t msg, uint32_t n, const char **key, const char **val, uint32_t *op) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
494 
495 /*!
496  * Create a new log message, query message, message list, or a connection to the system database.
497  *
498  * @param type
499  *    (input) ASL_TYPE_MSG, ASL_TYPE_QUERY, ASL_TYPE_LIST, or ASL_TYPE_CLIENT.
500  * @result Returns a newly allocated asl_object_t of the specified type.
501  *
502  * @discussion
503  *    New objects of type ASL_TYPE_CLIENT will be created with default settings for
504  *    a client connection, equivalent to asl_open(NULL, NULL, 0).
505  *    The Sender and Facility values associated with an ASL_TYPE_CLIENT may
506  *    be reset using asl_set().
507  */
508 asl_object_t asl_new(uint32_t type) __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);
509 
510 /*!
511  * Set or re-set a message or query attribute.
512  * May also be used to set values associated with an ASL_TYPE_CLIENT object,
513  * such as Sender and Facility.
514  *
515  * @param obj
516  *    (input) An ASL object of type ASL_TYPE_MSG, ASL_TYPE_QUERY, or ASL_TYPE_CLIENT.
517  * @param key
518  *    (input) Attribute key.
519  * @param value
520  *    (input) Attribute value.
521  * @result returns 0 for success, non-zero for failure.
522  */
523 int asl_set(asl_object_t obj, const char *key, const char *value) __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);
524 
525 /*!
526  * Remove a key/value attribute.
527  *
528  * @param obj
529  *    (input) An ASL object of type ASL_TYPE_MSG, ASL_TYPE_QUERY, or ASL_TYPE_CLIENT.
530  * @param key
531  *    (input) Attribute key.
532  * returns 0 for success, non-zero for failure.
533  */
534 int asl_unset(asl_object_t obj, const char *key) __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);
535 
536 /*!
537  * Get the value associated with an attribute key.
538  *
539  * @param obj
540  *    (input) An ASL object of type ASL_TYPE_MSG, ASL_TYPE_QUERY, or ASL_TYPE_CLIENT.
541  * @param key
542  *    (input) Attribute key.
543  * @result Returns the attribute value, or NULL if the object does not contain the key.
544  */
545 const char *asl_get(asl_object_t msg, const char *key) __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);
546 
547 /*!
548  * Log a message with a particular log level.
549  *
550  * @param obj
551  *    (input) An asl_object_t or NULL.
552  * @param msg
553  *    (input) An asl_object_t of type ASL_TYPE_MSG (default attributes will be supplied if msg is NULL).
554  * @param level
555  *    (input) Log level (ASL_LEVEL_DEBUG to ASL_LEVEL_EMERG).
556  * @param format
557  *    (input) A printf() - style format string followed by a list of arguments.
558  * @result Returns 0 for success, non-zero for failure.
559  *
560  * @discussion
561  *    The input object may be of any type.
562  *    In typical usage, obj is of type ASL_TYPE_CLIENT or obj is NULL.
563  *    NULL causes the library to use the default ASL client handle.
564  *    This routine prepares a message for tranmission to the ASL server daemon (syslogd),
565  *    The message is sent to the server subject to filter settings.  The message may also
566  *    be formatted and printed to various output files.
567  *
568  *    For ASL_TYPE_MSG, this routine will set all key/value pairs in the input object as
569  *    they would appear if the message were being sent to the server.  This includes
570  *    setting alues for ASL_KEY_TIME, ASL_KEY_TIME_NSEC, ASL_KEY_HOST, and so on.
571  *
572  *    If the object is of type ASL_TYPE_STORE or ASL_TYPE_FILE, a message will be
573  *    constructed (as above) and saved in the file or data store.  No filtering is done.
574  *
575  *    If obj is of type ASL_TYPE_LIST, a message is created and appended to the list.
576  *
577  *    The object type ASL_TYPE_QUERY is supported, but the key/value pairs set in the
578  *    object will have an operator value of zero.
579  */
580 int asl_log(asl_object_t client, asl_object_t msg, int level, const char *format, ...) __printflike(4, 5) __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);
581 
582 /*!
583  * Log a message with a particular log level.
584  *
585  * This API is a simplified version of asl_log().  It uses the default (NULL) ASL client handle,
586  * and does not have a msg parameter to supply additonal key/value pairs to be attached to the
587  * message sent to the syslogd server.
588  *
589  * @param level
590  *    (input) Log level (ASL_LEVEL_DEBUG to ASL_LEVEL_EMERG).
591  * @param format
592  *    (input) A printf() - style format string followed by a list of arguments.
593  * @result Returns 0 for success, non-zero for failure.
594  */
595 int asl_log_message(int level, const char *format, ...) __printflike(2, 3) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
596 
597 /*!
598  * Log a message with a particular log level.
599  * Similar to asl_log, but takes a va_list argument.
600  *
601  * @param asl
602  *    (input) An ASL object or NULL.
603  * @param msg
604  *    (input) An asl_object_t of type ASL_TYPE_MSG (default attributes will be supplied if msg is NULL).
605  * @param level
606  *    (input) Log level (ASL_LEVEL_DEBUG to ASL_LEVEL_EMERG).
607  * @param format
608  *    (input) A printf() - style format string followed by a list of arguments.
609  * @param ap
610  *    (input) A va_list containing the values for the format string.
611  * @result Returns 0 for success, non-zero for failure.
612  * @discussion
613  *    See the discussion for asl_log() for a description of how this routine treats different
614  *    types of input object.
615  *
616  */
617 int asl_vlog(asl_object_t obj, asl_object_t msg, int level, const char *format, va_list ap) __printflike(4, 0) __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);
618 
619 /*!
620  * Log a message.
621  *
622  * This routine may be used instead of asl_log() or asl_vlog() if asl_set()
623  * has been used to set all of a message's attributes.
624  *
625  * @param asl
626  *    (input) An ASL object or NULL.
627  * @param msg
628  *    (input) An asl_object_t of type ASL_TYPE_MSG.
629  * @result Returns 0 for success, non-zero for failure.
630  * @discussion
631  *    See the discussion for asl_log() for a description of how this routine treats different
632  *    types of input object.
633  */
634 int asl_send(asl_object_t obj, asl_object_t msg) __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);
635 
636 /*!
637  * DEPRECATED: Free an ASL object and all internal resources associated with it.
638  * This routine is identical to asl_release(), which should be used instead.
639  * Note that we don't issue a deprecation warning - yet.
640  *
641  * @param obj
642  *    (input) An ASL object to free.
643  */
644 void asl_free(asl_object_t obj) __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);
645 
646 /*!
647  * Increment the internal reference count of an ASL object.
648  *
649  * @param obj
650  *    (input) An ASL object to retain.
651  * @result Returns the object.
652  */
653 asl_object_t asl_retain(asl_object_t obj) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
654 
655 /*!
656  * Decrement the internal reference count of an ASL object.
657  * Frees the object when the reference count becomes zero.
658  *
659  * @param obj
660  *    (input) An ASL object to release.
661  */
662 void asl_release(asl_object_t obj) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
663 
664 /*!
665  * Get the internal type of an ASL object.
666  *
667  * @param obj
668  *    (input) An ASL object.
669  * @result Returns the object type.
670  */
671 uint32_t asl_get_type(asl_object_t obj) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
672 
673 /*!
674  * Set arbitrary parameters of a query.
675  * This is similar to asl_set, but allows richer query operations.
676  * See ASL_QUERY_OP_* above.
677  *
678  * @param msg
679  *    (input) An ASL object of type ASL_TYPE_QUERY.
680  * @param key
681  *    (input) Attribute key
682  * @param value
683  *    (input) Attribute value
684  * @param op
685  *    (input) An operation (ASL_QUERY_OP_*)
686  * @result Returns 0 for success, non-zero for failure
687  */
688 int asl_set_query(asl_object_t msg, const char *key, const char *value, uint32_t op) __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);
689 
690 /*!
691  * Search for messages matching the criteria described by an query object.
692  * The caller should set the attributes to match using asl_set_query() or asl_set().
693  * The operation ASL_QUERY_OP_EQUAL is used for attributes set with asl_set().
694  *
695  * @param obj
696  *    (input) An ASL object to search.
697  * @param query
698  *    (input) An asl_object_t of type ASL_TYPE_QUERY or ASL_TYPE_MSG.
699  *            query may be NULL, which matches anything.
700  * @result Returns an ASL object containing messages matching the query, or NULL if there are no matches.
701  *
702  * @discussion
703  *    The object to search may be of any type.
704  *    ASL_TYPE_CLIENT searches the main ASL database.
705  *    ASL_TYPE_STORE searches an ASL database in the filesystem.
706  *    ASL_TYPE_FILE searches an ASL data file in the filesystem.
707  *    ASL_TYPE_LIST searches for matches in a list of messages.
708  *
709  *    A NULL query matches anything.
710  *
711  *    If obj is of type ASL_TYPE_MSG and query is of type ASL_TYPE_QUERY, obj is matched against the query,
712  *    and a list containing the "obj" object is returned if the match succeeds.
713  *
714  *    If both obj and query are objects of type ASL_TYPE_MSG or both are of type ASL_TYPE_QUERY,
715  *    they are tested for exact match. A list containing the "obj" object is returned if the match is exact.
716  *
717  *    If obj is of type ASL_TYPE_QUERY and query is of type ASL_TYPE_MSG, the routine returns NULL.
718  *
719  */
720 asl_object_t asl_search(asl_object_t obj, asl_object_t query) __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_2_0);
721 
722 /*!
723  * DEPRECATED: Iterate over messages in an asl_object_t (same as an aslresponse).
724  * This routine is identical to asl_next().
725  *
726  * @param list
727  *    (input) An asl_object_t (aslresponse).
728  * @result Returns the next message contained in an ASL object, or NULL when there are no more messages.
729  *
730  * @discussion
731  *    This routine is deprecated in favor of asl_next().
732  */
733 asl_object_t aslresponse_next(asl_object_t obj) __OSX_AVAILABLE_BUT_DEPRECATED_MSG(__MAC_10_4,__MAC_10_10,__IPHONE_2_0,__IPHONE_7_0, "Use asl_next instead");
734 
735 /*!
736  * DEPRECATED: Free an asl_object_t.
737  * This routine is identical to asl_release().
738  *
739  * @param list
740  *    (input) An asl_object_t (aslresponse).
741  *
742  * @discussion
743  *    This routine is deprecated in favor of asl_release().
744  */
745 void aslresponse_free(asl_object_t obj) __OSX_AVAILABLE_BUT_DEPRECATED_MSG(__MAC_10_4,__MAC_10_10,__IPHONE_2_0,__IPHONE_7_0, "Use asl_release instead");
746 
747 /*!
748  * Append messages to an object of type ASL_TYPE_LIST.  The input "obj"
749  * parameter may be of type ASL_TYPE_MSG or ASL_TYPE_QUERY, in which case
750  * the object is appended to the list, or "obj" may be of type ASL_TYPE_LIST,
751  * in which case each object in that list is appended to the "list" object.
752  * Does nothing if either list or obj are NULL.
753  *
754  * @param obj
755  *    (input) An object of type ASLTYPE_CLIENT or ASL_TYPE_LIST, or an object of type
756  *    ASL_TYPE_FILE or ASL_TYPE_STORE that is open for write operations.
757  * @param obj_to_add
758  *    (input) An object of type ASL_TYPE_MSG, ASL_TYPE_QUERY or type ASL_TYPE_LIST.
759  */
760 void asl_append(asl_object_t obj, asl_object_t obj_to_add) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
761 
762 /*!
763  * Prepend messages to an object of type ASL_TYPE_LIST.  The input "obj"
764  * parameter may be of type ASL_TYPE_MSG or ASL_TYPE_QUERY, in which case
765  * the object is prepended to the list, or "obj" may be of type ASL_TYPE_LIST,
766  * in which case each object in that list is prepended to the "list" object.
767  * Does nothing if either list or obj are NULL.
768  *
769  * @param obj
770  *    (input) An object of type ASL_TYPE_LIST.
771  * @param obj_to_add
772  *    (input) An object of type ASL_TYPE_MSG, ASL_TYPE_QUERY or type ASL_TYPE_LIST.
773  */
774 void asl_prepend(asl_object_t obj, asl_object_t obj_to_add) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
775 
776 /*!
777  * Get the number of key/value pairs in an object of type ASL_TYPE_MSG or ASL_TYPE_QUERY,
778  * or the number of components in an object of type ASL_TYPE_LIST.
779  *
780  * @param obj
781  *    (input) An asl_object_t of type ASL_TYPE_MSG, ASL_TYPE_QUERY, or ASL_TYPE_LIST.
782  * @result The number of components in the object.
783  *    Returns zero if object is empty or NULL, or if the type is not
784  *    ASL_TYPE_MSG, ASL_TYPE_QUERY, or ASL_TYPE_LIST.
785  */
786 size_t asl_count(asl_object_t obj) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
787 
788 /*!
789  * Retreive a message from an object of type ASL_TYPE_LIST.
790  *
791  * @param obj
792  *    (input) An asl_object_t of type ASL_TYPE_LIST
793  * @result Returns the message (an object of type ASL_TYPE_MSG or ASL_TYPE_QUERY) at the specified index.
794  *    Returns NULL if the index is out of range or if list is not an object of type ASL_TYPE_LIST.
795  */
796 asl_object_t asl_get_index(asl_object_t list, size_t index) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
797 
798 /*!
799  * Remove the message at a specified index from an object of type ASL_TYPE_LIST.
800  *
801  * @param list
802  *    (input) An object of type ASL_TYPE_LIST.
803  */
804 void asl_remove_index(asl_object_t list, size_t index) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
805 
806 /*!
807  * Creates an auxiliary file that may be used to save arbitrary data.  The ASL message msg
808  * will be saved at the time that the auxiliary file is closed with asl_close_auxiliary_file().
809  * The log entry will include any keys and values found in msg, and it will include the title
810  * and Uniform Type Identifier specified.  If NULL is supplied as a value for the uti parameter,
811  * the type "public.data" is used.  Console.app will display a hyperlink to the file.
812  * Output parameter out_descriptor will contain a readable and writable file descriptor for the new
813  * auxiliary file.
814  *
815  * By default, the file will be world-readable.  If the message contains a ReadUID and/or a
816  * ReadGID key, then the values for those keys will determine read access to the file.
817  *
818  * The file will be deleted at the same time that the message expires from the ASL data store.
819  * The aslmanager utility manages message expiry.  If msg contains a value for ASLExpireTime,
820  * then the message and the file will not be deleted before that time.  The value may be in
821  * seconds after the Epoch, or it may be ctime() format, e.g "Thu Jun 24 18:22:48 2010".
822  *
823  * @param msg
824  *    (input) An object of type ASL_TYPE_MSG.
825  * @param tite
826  *    (input) A title string for the file.
827  * @param uti
828  *    (input) Uniform Type Identifier for the file.
829  * @param out_descriptor
830  *    (output) A writable file descriptor.
831  * @result Returns 0 for success, non-zero for failure
832  */
833 int asl_create_auxiliary_file(asl_object_t msg, const char *title, const char *uti, int *out_descriptor) __OSX_AVAILABLE_STARTING(__MAC_10_7,__IPHONE_5_0);
834 
835 /*!
836  * Close an auxiliary file opened by asl_create_auxiliary_file() when writing is complete.
837  * syslogd will log the message provided to asl_create_auxiliary_file() when this routine
838  * is called.
839  *
840  * @param descriptor
841  *    (input) The file descriptor
842  * @result Returns 0 for success, non-zero for failure
843  */
844 int asl_close_auxiliary_file(int descriptor) __OSX_AVAILABLE_STARTING(__MAC_10_7,__IPHONE_5_0);
845 
846 /*!
847  * Sends an ASL message to syslogd along with a title string, Uniform Resource Locator,
848  * and Uniform Type Identifier specified.  Console.app will hyperlink the title string to
849  * the specified URL.  If NULL is supplied as a value for the uti parameter, the default
850  * type "public.data" is used.
851  *
852  * @param msg
853  *    (input) An object of type ASL_TYPE_MSG.
854  * @param title
855  *    (input) A title string for the file
856  * @param uti
857  *    (input) Uniform Type Identifier for the file
858  * @param url
859  *    (input) Uniform Type Locator
860  * @result Returns 0 for success, non-zero for failure
861  */
862 int asl_log_auxiliary_location(asl_object_t msg, const char *title, const char *uti, const char *url) __OSX_AVAILABLE_STARTING(__MAC_10_7,__IPHONE_5_0);
863 
864 /*!
865  * Creates an object of type ASL_TYPE_CLIENT for logging to a file descriptor.
866  * The file must be opened for read and write access.  This routine may be used in conjunction
867  * with asl_create_auxiliary_file() to save ASL format log messages to an auxiliary file.
868  *
869  * When logging to the file is complete, the returned object should be released with asl_release().
870  * The file descriptor should be closed using asl_close_auxiliary_file() if it was returned by
871  * asl_create_auxiliary_file(), or close() otherwise.
872  *
873  * The returned client object is thread-safe.  It contains a lock that is aquired by
874  * the calling thread.  Note that this may cause unexpected syncronization behavior
875  * if multiple threads log to the returned object, or in applications that use the
876  * object in multiple dispatch queues.
877  *
878  * Note that per-message read access controls (ReadUID and ReadGID) and message expire
879  * times (ASLExpireTime) keys have no effect for messages written to this file.
880  *
881  * Also note that files are NOT truncated.  This is a change in OS X 10.9 and iOS 7.0.
882  * Previous versions of this routine truncated the file before writing.  Callers
883  * may use ftruncate() to truncate the file if desired.  If an existing non-empty
884  * file is used, it must be an ASL format data file.
885  *
886  * @param descriptor
887  *    (input) A file descriptor
888  * @param ident
889  *    (input) Sender name
890  * @param facility
891  *    (input) Facility name
892  * @result An object of type ASL_TYPE_CLIENT.
893  */
894 asl_object_t asl_open_from_file(int descriptor, const char *ident, const char *facility) __OSX_AVAILABLE_STARTING(__MAC_10_7,__IPHONE_5_0);
895 
896 /*!
897  * This API provides functionality to use file descriptors to send logging
898  * data to ASL.
899  *
900  * asl is retained by ASL and must still be closed by the caller by calling
901  * asl_close() if the caller loses reference to it.  msg is copied by ASL and
902  * similarly must still be freed by the caller by calling asl_free() if the
903  * caller loses reference to it.  Any changes made to it after calling
904  * asl_log_descriptor() are not applicable to the message used. descriptor
905  * is treated differentlty based on the value of fd_type.
906  *
907  * If fd_type is ASL_LOG_DESCRIPTOR_READ, the descriptor must be open for read
908  * access.  ASL uses GCD to read from the descriptor as data becomes available.
909  * These data are line buffered and passed to asl_log.  When EOF is read, the
910  * descriptor is closed.
911  *
912  * Example:
913  * asl_log_descriptor(c, m, ASL_LEVEL_NOTICE, STDIN_FILENO, ASL_LOG_DESCRIPTOR_READ);
914  *
915  * If fd_type is ASL_LOG_DESCRIPTOR_WRITE, the descriptor is closed and a new
916  * writable descriptor is created with the same fileno.  Any data written to
917  * this new descriptor are line buffered and passed to asl_log.  When EOF is
918  * sent, no further data are read.  The caller is responsible for closing the
919  * new descriptor.  One common use for this API is to redirect writes to stdout
920  * or stderr to ASL by passing STDOUT_FILENO or STDERR_FILENO as descriptor.
921  *
922  * Example:
923  * asl_log_descriptor(c, m, ASL_LEVEL_NOTICE, STDOUT_FILENO, ASL_LOG_DESCRIPTOR_WRITE);
924  * asl_log_descriptor(c, m, ASL_LEVEL_ERR, STDERR_FILENO, ASL_LOG_DESCRIPTOR_WRITE);
925  *
926  * @param client
927  *    (input) An ASL object of type ASL_TYPE_CLIENT.
928  * @param msg
929  *    (input) An asl_object_t of type ASL_TYPE_MSG (default attributes will be supplied if msg is NULL).
930  * @param level
931  *    (input) Log level (ASL_LEVEL_DEBUG to ASL_LEVEL_EMERG)
932  * @param descriptor
933  *    (input) An open file descriptor to read from
934  * @param fd_type
935  *    (input) Either ASL_LOG_DESCRIPTOR_READ or ASL_LOG_DESCRIPTOR_WRITE
936  * @result Returns 0 for success, non-zero for failure
937  */
938 int asl_log_descriptor(asl_object_t asl, asl_object_t msg, int level, int descriptor, uint32_t fd_type) __OSX_AVAILABLE_STARTING(__MAC_10_8,__IPHONE_5_1);
939 
940 #pragma mark -
941 
942 
943 /*!
944  * Creates a string representation of an ASL message.
945  *
946  * This utility creates a character string suitable for printing an ASL message.
947  * The returned string ends with a newline character.  The caller is responsible
948  * for freeing the returned string.
949  * The message is formatted according to the specified format string.  Timestamps
950  * are formatted accoring to the specified time format string.  Special characters
951  * are enoded as specified by the text_encoding parameter.
952  *
953  * @param msg
954  *    (input) An asl_object_t of type ASL_TYPE_MSG.
955  * @param fmt
956  *    (input) A format specification string.  See "Output file message and time formats"
957  *    for standard formats.  See the syslog(1) man page for more discussion on formats.
958  * @param fmt
959  *    (input) A time format specification string.  See "Output file message and time formats"
960  *    for standard formats.  See the syslog(1) man page for more discussion on time formats.
961  * @param text_encoding
962  *    (input) Text encoding control (for special characters).  See "Text Encoding Types".
963 * @result Returns a character string, or NULL in case of a failure.
964  */
965 char *asl_format(asl_object_t msg, const char *msg_fmt, const char *time_fmt, uint32_t text_encoding) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
966 
967 /*!
968  * Encodes a buffer with embedded nul characters into a nul terminated C string.
969  * The result must be freed by the caller.
970  *
971  * This utility is used to encode the value associated with ASL_KEY_AUX_DATA
972  * in an ASL_TYPE_MSG object.  An ASL_KEY_AUX_DATA key/value pair is used to hold the
973  * data written to a file descriptor created by asl_create_auxiliary_file on iOS
974  * systems, where the ASL database is stored in memory.
975  *
976  * @param buf
977  *    (input) Pointer to a data buffer.
978  * @param len
979  *    (input) Length (in octets) of data buffer.
980  * @result Returns an encoded character string.
981  */
982 char *asl_encode_buffer(const char *buf, size_t len) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
983 
984 /*!
985  * Decodes a C string previously created by asl_encode_buffer back into a buffer,
986  * possibly containing embedded nul characters.  Allocates memory for the buffer
987  * and returns a pointer in an output parameter "buf".
988  * The caller is responsible for freeing the buffer.
989  *
990  * This routine should be used to decode the value associated with an
991  * ASL_KEY_AUX_DATA key in an ASL_TYPE_MSG object.
992  *
993  * @param in
994  *    (input) Pointer to nul-terminated string created by asl_encode_buffer.
995  * @param buf
996  *    (output) Pointer to a newly allocated data buffer.
997  * @param len
998  *    (input) Length (in octets) of data buffer.
999  * @result Returns 0 on success, non-zero on failure.
1000  */
1001 int asl_decode_buffer(const char *in, char **buf, size_t *len) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
1002 
1003 /*!
1004  * Iterate forward through messages in an asl_object_t.
1005  * The asl_object_t object maintains an internal position index for the underlying
1006  * collection of ASL messages, whether the asl_object_t represents a list, a
1007  * data file, or an ASL database.  The position index is moved forward and the
1008  * "next" message is returned.
1009  *
1010  * @param obj
1011  *    (input) An asl_object_t.
1012  * @result Returns the next message (an object of type ASL_TYPE_MSG or ASL_TYPE_QUERY) from the object,
1013  *    which should be of type ASL_TYPE_CLIENT, ASL_TYPE_LIST, ASL_TYPE_STORE, or ASL_TYPE_FILE.
1014  *    Returns NULL when there are no more messages or if obj is not a type that holds messages.
1015  */
1016 asl_object_t asl_next(asl_object_t obj) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
1017 
1018 /*!
1019  * Iterate backwards through messages in an asl_object_t.
1020  * The asl_object_t object maintains an internal position index for the underlying
1021  * collection of ASL messages, whether the asl_object_t represents a list, a
1022  * data file, or an ASL database.  The position index is moved backward and the
1023  * "previous" message is returned.
1024  *
1025  * @param data
1026  *    (input) An asl_object_t.
1027  * @result Returns the previous message (an object of type ASL_TYPE_MSG or ASL_TYPE_QUERY) from the object,
1028  *    which should be of type ASL_TYPE_CLIENT, ASL_TYPE_LIST, ASL_TYPE_STORE, or ASL_TYPE_FILE.
1029  *    Returns NULL when there are no more messages or if obj is not a type that holds messages.
1030  */
1031 asl_object_t asl_prev(asl_object_t obj) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
1032 
1033 /*!
1034  * Reset internal interation index in an asl_object_t.
1035  *
1036  * @param obj
1037  *    (input) An object of type ASL_TYPE_CLIENT, ASL_TYPE_LIST, ASL_TYPE_STORE, or ASL_TYPE_FILE.
1038  * @param position
1039  *    (input) Use 0 to position the internal interation index at the beginning of the asl_object_t object,
1040  *    and SIZE_MAX to position it at the end.  Other values of position may cause unpredictable behavior.
1041  */
1042 void asl_reset_iteration(asl_object_t obj, size_t position) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
1043 
1044 /*!
1045  * Searches an asl_object_t.
1046  * The search is controlled by a list of queries, and returns a list with matching messages.
1047  * A message is returned if it matches any of the queries in the query list.
1048  * A NULL querylist matches anything.
1049  *
1050  * The caller may provide a starting ASL message ID, a direction, and a count.
1051  * A start ID value of 0 means that matching should commence at the beginning of the target obj.
1052  * A value of SIZE_MAX indicates that matching should commence at the end (most recent message)
1053  * in the target.  If a non-zero count value is supplied, the routine will return when it has
1054  * found that many messages, or it has checked all messages.  If a non-zero duration is supplied,
1055  * the routine will return after the specified time (in microseconds).
1056  * If both count and duration are non-zero, the routine will return when the desired number of
1057  * items has been matched or when the specified duration has been exceeded, whichever occurs first.
1058  * The search direction may be ASL_MATCH_DIRECTION_FORWARD or ASL_MATCH_DIRECTION_REVERSE.
1059  * The routine sets the value of the out parameter last to be an index of the last message
1060  * checked while matching.  To fetch matching messages in batches (using a small count or
1061  * duration value), the start value for each iteration should be set to (last + 1) if searching
1062  * forward, or (last - 1)for reverse search.
1063  *
1064  * @param data
1065  *    (input) An asl_object_t object.
1066  * @param querylist
1067  *    (input) An asl_object_t object containing zero or more queries.
1068  * @param last
1069  *    (output) An internal position index of the last message checked while matching in the asl_object_t object.
1070  * @param start
1071  *    (input) A position index specifying where matching should commence.
1072  * @param count
1073  *    (input) The maximum number of messages to be returned in the res output list (zero indicates no limit).
1074  * @param duration
1075  *    (input) A limit (in microseconds) on the time to be spent searching for results.  Zero indicates no time limit.
1076  * @param direction
1077  *    (input) ASL_MATCH_DIRECTION_FORWARD or ASL_MATCH_DIRECTION_REVERSE.
1078  * @result Returns an ASL object containing messages matching the querylist, or NULL if there are no matches.
1079  */
1080 asl_object_t asl_match(asl_object_t data, asl_object_t querylist, size_t *last, size_t start, size_t count, uint32_t duration, int32_t direction) __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_7_0);
1081 
1082 __END_DECLS
1083 
1084 #endif /* __ASL_H__ */
1085