1POSIX_TRACE_CREATE(3P) POSIX Programmer's Manual POSIX_TRACE_CREATE(3P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
12 posix_trace_create, posix_trace_create_withlog, posix_trace_flush,
13 posix_trace_shutdown — trace stream initialization, flush, and shutdown
14 from a process (TRACING)
15
17 #include <sys/types.h>
18 #include <trace.h>
19 int posix_trace_create(pid_t pid,
21 const trace_attr_t *restrict attr,
22 trace_id_t *restrict trid);
23 int posix_trace_create_withlog(pid_t pid,
24 const trace_attr_t *restrict attr, int file_desc,
25 trace_id_t *restrict trid);
26 int posix_trace_flush(trace_id_t trid);
27 int posix_trace_shutdown(trace_id_t trid);
28
30 The posix_trace_create() function shall create an active trace stream.
31 It allocates all the resources needed by the trace stream being created
32 for tracing the process specified by pid in accordance with the attr
33 argument. The attr argument represents the initial attributes of the
34 trace stream and shall have been initialized by the function
35 posix_trace_attr_init() prior to the posix_trace_create() call. If the
36 argument attr is NULL, the default attributes shall be used. The attr
37 attributes object shall be manipulated through a set of functions
38 described in the posix_trace_attr family of functions. If the
39 attributes of the object pointed to by attr are modified later, the
40 attributes of the trace stream shall not be affected. The creation-time
41 attribute of the newly created trace stream shall be set to the value
42 of the system clock, if the Timers option is not supported, or to the
43 value of the CLOCK_REALTIME clock, if the Timers option is supported.
44 The pid argument represents the target process to be traced. If the
46 process executing this function does not have appropriate privileges to
47 trace the process identified by pid, an error shall be returned. If the
48 pid argument is zero, the calling process shall be traced.
49 The posix_trace_create() function shall store the trace stream identi‐
51 fier of the new trace stream in the object pointed to by the trid argu‐
52 ment. This trace stream identifier shall be used in subsequent calls to
53 control tracing. The trid argument may only be used by the following
54 functions:
55 posix_trace_clear() posix_trace_getnext_event()
57 posix_trace_eventid_equal() posix_trace_shutdown()
58 posix_trace_eventid_get_name() posix_trace_start()
59 posix_trace_eventtypelist_getnext_id() posix_trace_stop()
60 posix_trace_eventtypelist_rewind() posix_trace_timedgetnext_event()
61 posix_trace_get_attr() posix_trace_trid_eventid_open()
62 posix_trace_get_status() posix_trace_trygetnext_event()
63 If the Trace Event Filter option is supported, the following additional
65 functions may use the trid argument:
66 posix_trace_get_filter() posix_trace_set_filter()
68 In particular, notice that the operations normally used by a trace ana‐
70 lyzer process, such as posix_trace_rewind() or posix_trace_close(),
71 cannot be invoked using the trace stream identifier returned by the
72 posix_trace_create() function.
73 A trace stream shall be created in a suspended state. If the Trace
75 Event Filter option is supported, its trace event type filter shall be
76 empty.
77 The posix_trace_create() function may be called multiple times from the
79 same or different processes, with the system-wide limit indicated by
80 the runtime invariant value {TRACE_SYS_MAX}, which has the minimum
81 value {_POSIX_TRACE_SYS_MAX}.
82 The trace stream identifier returned by the posix_trace_create() func‐
84 tion in the argument pointed to by trid is valid only in the process
85 that made the function call. If it is used from another process, that
86 is a child process, in functions defined in POSIX.1‐2008, these func‐
87 tions shall return with the error [EINVAL].
88 The posix_trace_create_withlog() function shall be equivalent to
90 posix_trace_create(), except that it associates a trace log with this
91 stream. The file_desc argument shall be the file descriptor designating
92 the trace log destination. The function shall fail if this file
93 descriptor refers to a file with a file type that is not compatible
94 with the log policy associated with the trace log. The list of the
95 appropriate file types that are compatible with each log policy is
96 implementation-defined.
97 The posix_trace_create_withlog() function shall return in the parameter
99 pointed to by trid the trace stream identifier, which uniquely identi‐
100 fies the newly created trace stream, and shall be used in subsequent
101 calls to control tracing. The trid argument may only be used by the
102 following functions:
103 posix_trace_clear() posix_trace_get_status()
105 posix_trace_eventid_equal() posix_trace_getnext_event()
106 posix_trace_eventid_get_name() posix_trace_shutdown()
107 posix_trace_eventtypelist_getnext_id() posix_trace_start()
108 posix_trace_eventtypelist_rewind() posix_trace_stop()
109 posix_trace_flush() posix_trace_timedgetnext_event()
110 posix_trace_get_attr() posix_trace_trid_eventid_open()
111 If the Trace Event Filter option is supported, the following additional
113 functions may use the trid argument:
114 posix_trace_get_filter() posix_trace_set_filter()
116 In particular, notice that the operations normally used by a trace ana‐
118 lyzer process, such as posix_trace_rewind() or posix_trace_close(),
119 cannot be invoked using the trace stream identifier returned by the
120 posix_trace_create_withlog() function.
121 The posix_trace_flush() function shall initiate a flush operation which
123 copies the contents of the trace stream identified by the argument trid
124 into the trace log associated with the trace stream at the creation
125 time. If no trace log has been associated with the trace stream pointed
126 to by trid, this function shall return an error. The termination of the
127 flush operation can be polled by the posix_trace_get_status() function.
128 During the flush operation, it shall be possible to trace new trace
129 events up to the point when the trace stream becomes full. After
130 flushing is completed, the space used by the flushed trace events shall
131 be available for tracing new trace events.
132 If flushing the trace stream causes the resulting trace log to become
134 full, the trace log full policy shall be applied. If the trace log-
135 full-policy attribute is set, the following occurs:
136 POSIX_TRACE_UNTIL_FULL
138 The trace events that have not yet been flushed shall be dis‐
139 carded.
140 POSIX_TRACE_LOOP
142 The trace events that have not yet been flushed shall be written
143 to the beginning of the trace log, overwriting previous trace
144 events stored there.
145 POSIX_TRACE_APPEND
147 The trace events that have not yet been flushed shall be appended
148 to the trace log.
149 The posix_trace_shutdown() function shall stop the tracing of trace
151 events in the trace stream identified by trid, as if posix_trace_stop()
152 had been invoked. The posix_trace_shutdown() function shall free all
153 the resources associated with the trace stream.
154 The posix_trace_shutdown() function shall not return until all the
156 resources associated with the trace stream have been freed. When the
157 posix_trace_shutdown() function returns, the trid argument becomes an
158 invalid trace stream identifier. A call to this function shall uncondi‐
159 tionally deallocate the resources regardless of whether all trace
160 events have been retrieved by the analyzer process. Any thread blocked
161 on one of the trace_getnext_event() functions (which specified this
162 trid) before this call is unblocked with the error [EINVAL].
163 If the process exits, invokes a member of the exec family of functions,
165 or is terminated, the trace streams that the process had created and
166 that have not yet been shut down, shall be automatically shut down as
167 if an explicit call were made to the posix_trace_shutdown() function.
168 For an active trace stream with log, when the posix_trace_shutdown()
170 function is called, all trace events that have not yet been flushed to
171 the trace log shall be flushed, as in the posix_trace_flush() function,
172 and the trace log shall be closed.
173 When a trace log is closed, all the information that may be retrieved
175 later from the trace log through the trace interface shall have been
176 written to the trace log. This information includes the trace
177 attributes, the list of trace event types (with the mapping between
178 trace event names and trace event type identifiers), and the trace sta‐
179 tus.
180 In addition, unspecified information shall be written to the trace log
182 to allow detection of a valid trace log during the posix_trace_open()
183 operation.
184 The posix_trace_shutdown() function shall not return until all trace
186 events have been flushed.
187
189 Upon successful completion, these functions shall return a value of
190 zero. Otherwise, they shall return the corresponding error number.
191 The posix_trace_create() and posix_trace_create_withlog() functions
193 store the trace stream identifier value in the object pointed to by
194 trid, if successful.
195
197 The posix_trace_create() and posix_trace_create_withlog() functions
198 shall fail if:
199 EAGAIN No more trace streams can be started now. {TRACE_SYS_MAX} has
201 been exceeded.
202 EINTR The operation was interrupted by a signal. No trace stream was
204 created.
205 EINVAL One or more of the trace parameters specified by the attr param‐
207 eter is invalid.
208 ENOMEM The implementation does not currently have sufficient memory to
210 create the trace stream with the specified parameters.
211 EPERM The caller does not have appropriate privileges to trace the
213 process specified by pid.
214 ESRCH The pid argument does not refer to an existing process.
216 The posix_trace_create_withlog() function shall fail if:
218 EBADF The file_desc argument is not a valid file descriptor open for
220 writing.
221 EINVAL The file_desc argument refers to a file with a file type that
223 does not support the log policy associated with the trace log.
224 ENOSPC No space left on device. The device corresponding to the argu‐
226 ment file_desc does not contain the space required to create
227 this trace log.
228 The posix_trace_flush() and posix_trace_shutdown() functions shall fail
230 if:
231 EINVAL The value of the trid argument does not correspond to an active
233 trace stream with log.
234 EFBIG The trace log file has attempted to exceed an implementation-
236 defined maximum file size.
237 ENOSPC No space left on device.
239 The following sections are informative.
241
243 None.
244
246 None.
247
249 None.
250
252 The posix_trace_create(), posix_trace_create_withlog(),
253 posix_trace_flush(), and posix_trace_shutdown() functions may be
254 removed in a future version.
255
257 clock_getres(), exec, posix_trace_attr_destroy(), posix_trace_clear(),
258 posix_trace_close(), posix_trace_eventid_equal(), posix_trace_event‐
259 typelist_getnext_id(), posix_trace_get_attr(), posix_trace_get_fil‐
260 ter(), posix_trace_getnext_event(), posix_trace_start(),
261 posix_trace_start(), time()
262 The Base Definitions volume of POSIX.1‐2017, <sys_types.h>, <trace.h>
264
266 Portions of this text are reprinted and reproduced in electronic form
267 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
268 table Operating System Interface (POSIX), The Open Group Base Specifi‐
269 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
270 Electrical and Electronics Engineers, Inc and The Open Group. In the
271 event of any discrepancy between this version and the original IEEE and
272 The Open Group Standard, the original IEEE and The Open Group Standard
273 is the referee document. The original Standard can be obtained online
274 at http://www.opengroup.org/unix/online.html .
275 Any typographical or formatting errors that appear in this page are
277 most likely to have been introduced during the conversion of the source
278 files to man page format. To report such errors, see https://www.ker‐
279 nel.org/doc/man-pages/reporting_bugs.html .
280IEEE/The Open Group 2017 POSIX_TRACE_CREATE(3P)