posix_trace_create(3p) — Linux manual page

PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

POSIX_TRACE_CREATE(3P)  POSIX Programmer's Manual POSIX_TRACE_CREATE(3P)

PROLOG         top

       This manual page is part of the POSIX Programmer's Manual.  The
       Linux implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior),
       or the interface may not be implemented on Linux.

NAME         top

       posix_trace_create, posix_trace_create_withlog,
       posix_trace_flush, posix_trace_shutdown — trace stream
       initialization, flush, and shutdown from a process (TRACING)

SYNOPSIS         top

       #include <sys/types.h>
       #include <trace.h>

       int posix_trace_create(pid_t pid,
           const trace_attr_t *restrict attr,
           trace_id_t *restrict trid);
       int posix_trace_create_withlog(pid_t pid,
           const trace_attr_t *restrict attr, int file_desc,
           trace_id_t *restrict trid);
       int posix_trace_flush(trace_id_t trid);
       int posix_trace_shutdown(trace_id_t trid);

DESCRIPTION         top

       The posix_trace_create() function shall create an active trace
       stream. It allocates all the resources needed by the trace stream
       being created for tracing the process specified by pid in
       accordance with the attr argument. The attr argument represents
       the initial attributes of the trace stream and shall have been
       initialized by the function posix_trace_attr_init() prior to the
       posix_trace_create() call. If the argument attr is NULL, the
       default attributes shall be used. The attr attributes object
       shall be manipulated through a set of functions described in the
       posix_trace_attr family of functions. If the attributes of the
       object pointed to by attr are modified later, the attributes of
       the trace stream shall not be affected. The creation-time
       attribute of the newly created trace stream shall be set to the
       value of the system clock, if the Timers option is not supported,
       or to the value of the CLOCK_REALTIME clock, if the Timers option
       is supported.

       The pid argument represents the target process to be traced. If
       the process executing this function does not have appropriate
       privileges to trace the process identified by pid, an error shall
       be returned. If the pid argument is zero, the calling process
       shall be traced.

       The posix_trace_create() function shall store the trace stream
       identifier of the new trace stream in the object pointed to by
       the trid argument. This trace stream identifier shall be used in
       subsequent calls to control tracing. The trid argument may only
       be used by the following functions:

       posix_trace_clear()                      posix_trace_getnext_event()
       posix_trace_eventid_equal()              posix_trace_shutdown()
       posix_trace_eventid_get_name()           posix_trace_start()
       posix_trace_eventtypelist_getnext_id()   posix_trace_stop()
       posix_trace_eventtypelist_rewind()       posix_trace_timedgetnext_event()
       posix_trace_get_attr()                   posix_trace_trid_eventid_open()
       posix_trace_get_status()                 posix_trace_trygetnext_event()

       If the Trace Event Filter option is supported, the following
       additional functions may use the trid argument:

       posix_trace_get_filter()   posix_trace_set_filter()

       In particular, notice that the operations normally used by a
       trace analyzer process, such as posix_trace_rewind() or
       posix_trace_close(), cannot be invoked using the trace stream
       identifier returned by the posix_trace_create() function.

       A trace stream shall be created in a suspended state.  If the
       Trace Event Filter option is supported, its trace event type
       filter shall be empty.

       The posix_trace_create() function may be called multiple times
       from the same or different processes, with the system-wide limit
       indicated by the runtime invariant value {TRACE_SYS_MAX}, which
       has the minimum value {_POSIX_TRACE_SYS_MAX}.

       The trace stream identifier returned by the posix_trace_create()
       function in the argument pointed to by trid is valid only in the
       process that made the function call. If it is used from another
       process, that is a child process, in functions defined in
       POSIX.1‐2008, these functions shall return with the error
       [EINVAL].

       The posix_trace_create_withlog() function shall be equivalent to
       posix_trace_create(), except that it associates a trace log with
       this stream. The file_desc argument shall be the file descriptor
       designating the trace log destination. The function shall fail if
       this file descriptor refers to a file with a file type that is
       not compatible with the log policy associated with the trace log.
       The list of the appropriate file types that are compatible with
       each log policy is implementation-defined.

       The posix_trace_create_withlog() function shall return in the
       parameter pointed to by trid the trace stream identifier, which
       uniquely identifies the newly created trace stream, and shall be
       used in subsequent calls to control tracing. The trid argument
       may only be used by the following functions:

       posix_trace_clear()                      posix_trace_get_status()
       posix_trace_eventid_equal()              posix_trace_getnext_event()
       posix_trace_eventid_get_name()           posix_trace_shutdown()
       posix_trace_eventtypelist_getnext_id()   posix_trace_start()
       posix_trace_eventtypelist_rewind()       posix_trace_stop()
       posix_trace_flush()                      posix_trace_timedgetnext_event()
       posix_trace_get_attr()                   posix_trace_trid_eventid_open()

       If the Trace Event Filter option is supported, the following
       additional functions may use the trid argument:

       posix_trace_get_filter()   posix_trace_set_filter()

       In particular, notice that the operations normally used by a
       trace analyzer process, such as posix_trace_rewind() or
       posix_trace_close(), cannot be invoked using the trace stream
       identifier returned by the posix_trace_create_withlog() function.

       The posix_trace_flush() function shall initiate a flush operation
       which copies the contents of the trace stream identified by the
       argument trid into the trace log associated with the trace stream
       at the creation time. If no trace log has been associated with
       the trace stream pointed to by trid, this function shall return
       an error. The termination of the flush operation can be polled by
       the posix_trace_get_status() function. During the flush
       operation, it shall be possible to trace new trace events up to
       the point when the trace stream becomes full.  After flushing is
       completed, the space used by the flushed trace events shall be
       available for tracing new trace events.

       If flushing the trace stream causes the resulting trace log to
       become full, the trace log full policy shall be applied. If the
       trace log-full-policy attribute is set, the following occurs:

       POSIX_TRACE_UNTIL_FULL
             The trace events that have not yet been flushed shall be
             discarded.

       POSIX_TRACE_LOOP
             The trace events that have not yet been flushed shall be
             written to the beginning of the trace log, overwriting
             previous trace events stored there.

       POSIX_TRACE_APPEND
             The trace events that have not yet been flushed shall be
             appended to the trace log.

       The posix_trace_shutdown() function shall stop the tracing of
       trace events in the trace stream identified by trid, as if
       posix_trace_stop() had been invoked. The posix_trace_shutdown()
       function shall free all the resources associated with the trace
       stream.

       The posix_trace_shutdown() function shall not return until all
       the resources associated with the trace stream have been freed.
       When the posix_trace_shutdown() function returns, the trid
       argument becomes an invalid trace stream identifier. A call to
       this function shall unconditionally deallocate the resources
       regardless of whether all trace events have been retrieved by the
       analyzer process.  Any thread blocked on one of the
       trace_getnext_event() functions (which specified this trid)
       before this call is unblocked with the error [EINVAL].

       If the process exits, invokes a member of the exec family of
       functions, or is terminated, the trace streams that the process
       had created and that have not yet been shut down, shall be
       automatically shut down as if an explicit call were made to the
       posix_trace_shutdown() function.

       For an active trace stream with log, when the
       posix_trace_shutdown() function is called, all trace events that
       have not yet been flushed to the trace log shall be flushed, as
       in the posix_trace_flush() function, and the trace log shall be
       closed.

       When a trace log is closed, all the information that may be
       retrieved later from the trace log through the trace interface
       shall have been written to the trace log. This information
       includes the trace attributes, the list of trace event types
       (with the mapping between trace event names and trace event type
       identifiers), and the trace status.

       In addition, unspecified information shall be written to the
       trace log to allow detection of a valid trace log during the
       posix_trace_open() operation.

       The posix_trace_shutdown() function shall not return until all
       trace events have been flushed.

RETURN VALUE         top

       Upon successful completion, these functions shall return a value
       of zero. Otherwise, they shall return the corresponding error
       number.

       The posix_trace_create() and posix_trace_create_withlog()
       functions store the trace stream identifier value in the object
       pointed to by trid, if successful.

ERRORS         top

       The posix_trace_create() and posix_trace_create_withlog()
       functions shall fail if:

       EAGAIN No more trace streams can be started now.  {TRACE_SYS_MAX}
              has been exceeded.

       EINTR  The operation was interrupted by a signal. No trace stream
              was created.

       EINVAL One or more of the trace parameters specified by the attr
              parameter is invalid.

       ENOMEM The implementation does not currently have sufficient
              memory to create the trace stream with the specified
              parameters.

       EPERM  The caller does not have appropriate privileges to trace
              the process specified by pid.

       ESRCH  The pid argument does not refer to an existing process.

       The posix_trace_create_withlog() function shall fail if:

       EBADF  The file_desc argument is not a valid file descriptor open
              for writing.

       EINVAL The file_desc argument refers to a file with a file type
              that does not support the log policy associated with the
              trace log.

       ENOSPC No space left on device. The device corresponding to the
              argument file_desc does not contain the space required to
              create this trace log.

       The posix_trace_flush() and posix_trace_shutdown() functions
       shall fail if:

       EINVAL The value of the trid argument does not correspond to an
              active trace stream with log.

       EFBIG  The trace log file has attempted to exceed an
              implementation-defined maximum file size.

       ENOSPC No space left on device.

       The following sections are informative.

EXAMPLES         top

       None.

APPLICATION USAGE         top

       None.

RATIONALE         top

       None.

FUTURE DIRECTIONS         top

       The posix_trace_create(), posix_trace_create_withlog(),
       posix_trace_flush(), and posix_trace_shutdown() functions may be
       removed in a future version.

SEE ALSO         top

       clock_getres(3p), exec(1p), posix_trace_attr_destroy(3p),
       posix_trace_clear(3p), posix_trace_close(3p),
       posix_trace_eventid_equal(3p),
       posix_trace_eventtypelist_getnext_id(3p),
       posix_trace_get_attr(3p), posix_trace_get_filter(3p),
       posix_trace_getnext_event(3p), posix_trace_start(3p),
       posix_trace_start(3p), time(3p)

       The Base Definitions volume of POSIX.1‐2017, sys_types.h(0p),
       trace.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 by the Institute of Electrical and Electronics
       Engineers, Inc and The Open Group.  In the event of any
       discrepancy between this version and the original IEEE and The
       Open Group Standard, the original IEEE and The Open Group
       Standard is the referee document. The original Standard can be
       obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page
       are most likely to have been introduced during the conversion of
       the source files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group               2017            POSIX_TRACE_CREATE(3P)

Pages that refer to this page: trace.h(0p)exec(3p)_Exit(3p)posix_trace_attr_destroy(3p)posix_trace_attr_getclockres(3p)posix_trace_attr_getinherited(3p)posix_trace_attr_getlogsize(3p)posix_trace_clear(3p)posix_trace_flush(3p)posix_trace_get_attr(3p)posix_trace_getnext_event(3p)posix_trace_shutdown(3p)posix_trace_start(3p)