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
13 posix_trace_create, posix_trace_create_withlog, posix_trace_flush,
14 posix_trace_shutdown — trace stream initialization, flush, and shutdown
15 from a process (TRACING)
16
18 #include <sys/types.h>
19 #include <trace.h>
20 int posix_trace_create(pid_t pid,
22 const trace_attr_t *restrict attr,
23 trace_id_t *restrict trid);
24 int posix_trace_create_withlog(pid_t pid,
25 const trace_attr_t *restrict attr, int file_desc,
26 trace_id_t *restrict trid);
27 int posix_trace_flush(trace_id_t trid);
28 int posix_trace_shutdown(trace_id_t trid);
29
31 The posix_trace_create() function shall create an active trace stream.
32 It allocates all the resources needed by the trace stream being created
33 for tracing the process specified by pid in accordance with the attr
34 argument. The attr argument represents the initial attributes of the
35 trace stream and shall have been initialized by the function
36 posix_trace_attr_init() prior to the posix_trace_create() call. If the
37 argument attr is NULL, the default attributes shall be used. The attr
38 attributes object shall be manipulated through a set of functions
39 described in the posix_trace_attr family of functions. If the
40 attributes of the object pointed to by attr are modified later, the
41 attributes of the trace stream shall not be affected. The creation-time
42 attribute of the newly created trace stream shall be set to the value
43 of the system clock, if the Timers option is not supported, or to the
44 value of the CLOCK_REALTIME clock, if the Timers option is supported.
45 The pid argument represents the target process to be traced. If the
47 process executing this function does not have appropriate privileges to
48 trace the process identified by pid, an error shall be returned. If the
49 pid argument is zero, the calling process shall be traced.
50 The posix_trace_create() function shall store the trace stream identi‐
52 fier of the new trace stream in the object pointed to by the trid argu‐
53 ment. This trace stream identifier shall be used in subsequent calls to
54 control tracing. The trid argument may only be used by the following
55 functions:
56 posix_trace_clear() posix_trace_getnext_event()
58 posix_trace_eventid_equal() posix_trace_shutdown()
59 posix_trace_eventid_get_name() posix_trace_start()
60 posix_trace_eventtypelist_getnext_id() posix_trace_stop()
61 posix_trace_eventtypelist_rewind() posix_trace_timedgetnext_event()
62 posix_trace_get_attr() posix_trace_trid_eventid_open()
63 posix_trace_get_status() posix_trace_trygetnext_event()
64 If the Trace Event Filter option is supported, the following additional
66 functions may use the trid argument:
67 posix_trace_get_filter() posix_trace_set_filter()
69 In particular, notice that the operations normally used by a trace ana‐
71 lyzer process, such as posix_trace_rewind() or posix_trace_close(),
72 cannot be invoked using the trace stream identifier returned by the
73 posix_trace_create() function.
74 A trace stream shall be created in a suspended state. If the Trace
76 Event Filter option is supported, its trace event type filter shall be
77 empty.
78 The posix_trace_create() function may be called multiple times from the
80 same or different processes, with the system-wide limit indicated by
81 the runtime invariant value {TRACE_SYS_MAX}, which has the minimum
82 value {_POSIX_TRACE_SYS_MAX}.
83 The trace stream identifier returned by the posix_trace_create() func‐
85 tion in the argument pointed to by trid is valid only in the process
86 that made the function call. If it is used from another process, that
87 is a child process, in functions defined in POSIX.1‐2008, these func‐
88 tions shall return with the error [EINVAL].
89 The posix_trace_create_withlog() function shall be equivalent to
91 posix_trace_create(), except that it associates a trace log with this
92 stream. The file_desc argument shall be the file descriptor designating
93 the trace log destination. The function shall fail if this file
94 descriptor refers to a file with a file type that is not compatible
95 with the log policy associated with the trace log. The list of the
96 appropriate file types that are compatible with each log policy is
97 implementation-defined.
98 The posix_trace_create_withlog() function shall return in the parameter
100 pointed to by trid the trace stream identifier, which uniquely identi‐
101 fies the newly created trace stream, and shall be used in subsequent
102 calls to control tracing. The trid argument may only be used by the
103 following functions:
104 posix_trace_clear() posix_trace_get_status()
106 posix_trace_eventid_equal() posix_trace_getnext_event()
107 posix_trace_eventid_get_name() posix_trace_shutdown()
108 posix_trace_eventtypelist_getnext_id() posix_trace_start()
109 posix_trace_eventtypelist_rewind() posix_trace_stop()
110 posix_trace_flush() posix_trace_timedgetnext_event()
111 posix_trace_get_attr() posix_trace_trid_eventid_open()
112 If the Trace Event Filter option is supported, the following additional
114 functions may use the trid argument:
115 posix_trace_get_filter() posix_trace_set_filter()
117 In particular, notice that the operations normally used by a trace ana‐
119 lyzer process, such as posix_trace_rewind() or posix_trace_close(),
120 cannot be invoked using the trace stream identifier returned by the
121 posix_trace_create_withlog() function.
122 The posix_trace_flush() function shall initiate a flush operation which
124 copies the contents of the trace stream identified by the argument trid
125 into the trace log associated with the trace stream at the creation
126 time. If no trace log has been associated with the trace stream pointed
127 to by trid, this function shall return an error. The termination of the
128 flush operation can be polled by the posix_trace_get_status() function.
129 During the flush operation, it shall be possible to trace new trace
130 events up to the point when the trace stream becomes full. After
131 flushing is completed, the space used by the flushed trace events shall
132 be available for tracing new trace events.
133 If flushing the trace stream causes the resulting trace log to become
135 full, the trace log full policy shall be applied. If the trace log-
136 full-policy attribute is set, the following occurs:
137 POSIX_TRACE_UNTIL_FULL
139 The trace events that have not yet been flushed shall be dis‐
140 carded.
141 POSIX_TRACE_LOOP
143 The trace events that have not yet been flushed shall be written
144 to the beginning of the trace log, overwriting previous trace
145 events stored there.
146 POSIX_TRACE_APPEND
148 The trace events that have not yet been flushed shall be appended
149 to the trace log.
150 The posix_trace_shutdown() function shall stop the tracing of trace
152 events in the trace stream identified by trid, as if posix_trace_stop()
153 had been invoked. The posix_trace_shutdown() function shall free all
154 the resources associated with the trace stream.
155 The posix_trace_shutdown() function shall not return until all the
157 resources associated with the trace stream have been freed. When the
158 posix_trace_shutdown() function returns, the trid argument becomes an
159 invalid trace stream identifier. A call to this function shall uncondi‐
160 tionally deallocate the resources regardless of whether all trace
161 events have been retrieved by the analyzer process. Any thread blocked
162 on one of the trace_getnext_event() functions (which specified this
163 trid) before this call is unblocked with the error [EINVAL].
164 If the process exits, invokes a member of the exec family of functions,
166 or is terminated, the trace streams that the process had created and
167 that have not yet been shut down, shall be automatically shut down as
168 if an explicit call were made to the posix_trace_shutdown() function.
169 For an active trace stream with log, when the posix_trace_shutdown()
171 function is called, all trace events that have not yet been flushed to
172 the trace log shall be flushed, as in the posix_trace_flush() function,
173 and the trace log shall be closed.
174 When a trace log is closed, all the information that may be retrieved
176 later from the trace log through the trace interface shall have been
177 written to the trace log. This information includes the trace
178 attributes, the list of trace event types (with the mapping between
179 trace event names and trace event type identifiers), and the trace sta‐
180 tus.
181 In addition, unspecified information shall be written to the trace log
183 to allow detection of a valid trace log during the posix_trace_open()
184 operation.
185 The posix_trace_shutdown() function shall not return until all trace
187 events have been flushed.
188
190 Upon successful completion, these functions shall return a value of
191 zero. Otherwise, they shall return the corresponding error number.
192 The posix_trace_create() and posix_trace_create_withlog() functions
194 store the trace stream identifier value in the object pointed to by
195 trid, if successful.
196
198 The posix_trace_create() and posix_trace_create_withlog() functions
199 shall fail if:
200 EAGAIN No more trace streams can be started now. {TRACE_SYS_MAX} has
202 been exceeded.
203 EINTR The operation was interrupted by a signal. No trace stream was
205 created.
206 EINVAL One or more of the trace parameters specified by the attr param‐
208 eter is invalid.
209 ENOMEM The implementation does not currently have sufficient memory to
211 create the trace stream with the specified parameters.
212 EPERM The caller does not have appropriate privileges to trace the
214 process specified by pid.
215 ESRCH The pid argument does not refer to an existing process.
217 The posix_trace_create_withlog() function shall fail if:
219 EBADF The file_desc argument is not a valid file descriptor open for
221 writing.
222 EINVAL The file_desc argument refers to a file with a file type that
224 does not support the log policy associated with the trace log.
225 ENOSPC No space left on device. The device corresponding to the argu‐
227 ment file_desc does not contain the space required to create
228 this trace log.
229 The posix_trace_flush() and posix_trace_shutdown() functions shall fail
231 if:
232 EINVAL The value of the trid argument does not correspond to an active
234 trace stream with log.
235 EFBIG The trace log file has attempted to exceed an implementation-
237 defined maximum file size.
238 ENOSPC No space left on device.
240 The following sections are informative.
242
244 None.
245
247 None.
248
250 None.
251
253 The posix_trace_create(), posix_trace_create_withlog(),
254 posix_trace_flush(), and posix_trace_shutdown() functions may be
255 removed in a future version.
256
258 clock_getres(), exec, posix_trace_attr_destroy(), posix_trace_clear(),
259 posix_trace_close(), posix_trace_eventid_equal(), posix_trace_event‐
260 typelist_getnext_id(), posix_trace_get_attr(), posix_trace_get_fil‐
261 ter(), posix_trace_getnext_event(), posix_trace_start(),
262 posix_trace_start(), time()
263 The Base Definitions volume of POSIX.1‐2008, <sys_types.h>, <trace.h>
265
267 Portions of this text are reprinted and reproduced in electronic form
268 from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
269 -- Portable Operating System Interface (POSIX), The Open Group Base
270 Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
271 cal and Electronics Engineers, Inc and The Open Group. (This is
272 POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
273 event of any discrepancy between this version and the original IEEE and
274 The Open Group Standard, the original IEEE and The Open Group Standard
275 is the referee document. The original Standard can be obtained online
276 at http://www.unix.org/online.html .
277 Any typographical or formatting errors that appear in this page are
279 most likely to have been introduced during the conversion of the source
280 files to man page format. To report such errors, see https://www.ker‐
281 nel.org/doc/man-pages/reporting_bugs.html .
282IEEE/The Open Group 2013 POSIX_TRACE_CREATE(3P)