| Message ID | 20190412133811.15878-12-tstoyanov@vmware.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Libtraceevent MAN pages | expand |
On Fri, 12 Apr 2019 16:37:52 +0300 Tzvetomir Stoyanov <tstoyanov@vmware.com> wrote: > Create man pages for libtraceevent APIs: > tep_register_event_handler() > tep_unregister_event_handler() > > Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com> > --- > .../libtraceevent-reg_event_handler.txt | 131 ++++++++++++++++++ > 1 file changed, 131 insertions(+) > create mode 100644 tools/lib/traceevent/Documentation/libtraceevent-reg_event_handler.txt > > diff --git a/tools/lib/traceevent/Documentation/libtraceevent-reg_event_handler.txt b/tools/lib/traceevent/Documentation/libtraceevent-reg_event_handler.txt > new file mode 100644 > index 000000000000..8b1b75da7628 > --- /dev/null > +++ b/tools/lib/traceevent/Documentation/libtraceevent-reg_event_handler.txt > @@ -0,0 +1,131 @@ > +libtraceevent(3) > +================ > + > +NAME > +---- > +tep_register_event_handler, tep_unregister_event_handler - Register / > +unregisters a callback function to parse an event information. > + > +SYNOPSIS > +-------- > +[verse] > +-- > +*#include <event-parse.h>* > + > +enum *tep_reg_handler* { > + _TEP_REGISTER_SUCCESS_, > + _TEP_REGISTER_SUCCESS_OVERWRITE_, > +}; > + > +int *tep_register_event_handler*(struct tep_handle pass:[*]_tep_, int _id_, const char pass:[*]_sys_name_, const char pass:[*]_event_name_, tep_event_handler_func _func_, void pass:[*]_context_); > +int *tep_unregister_event_handler*(struct tep_handle pass:[*]tep, int id, const char pass:[*]sys_name, const char pass:[*]event_name, tep_event_handler_func func, void pass:[*]_context_); > + > +typedef int (*pass:[*]tep_event_handler_func*)(struct trace_seq pass:[*]s, struct tep_record pass:[*]record, struct tep_event pass:[*]event, void pass:[*]context); > +-- > + > +DESCRIPTION > +----------- > +The _tep_register_event_handler()_ function registers a handler function, > +which is going to be called to parse the information for a given event. > +The _tep_ argument is the trace event parser context. The _id_ argument is > +the id of the event. The _sys_name_ argument is the name of the system, > +the event belongs to. The _event_name_ argument is the name of the event. > +If _id_ is >= 0, it is used to find the event, otherwise _sys_name_ and > +_event_name_ are used. The _func_ is a pointer to the function, which is going > +to be called to parse the event information. The _context_ argument is a pointer > +to the context data, which will be passed to the _func_. If a handler function > +for the same event is already registered, it will be overridden with the new > +one. This mechanism allows a developer to override the parsing of a given event. > +If for some reason the default print format is not sufficient, the developer > +can register a function for an event to be used to parse the data instead. > + > +The _tep_unregister_event_handler()_ function unregisters the handler function, > +previously registered with _tep_register_event_handler()_. The _tep_ argument > +is the trace event parser context. The _id_, _sys_name_, _event_name_, _func_, > +and _context_ are the same arguments, as when the callback function _func_ was > +registered. > + > +The _tep_event_handler_func_ is the type of the custom event handler > +function. The _s_ argument is the trace sequence, it can be used to create a > +custom string, describing the event. A _record_ to get the event from is passed > +as input parameter and also the _event_ - the handle to the record's event. The > +_context_ is custom context, set when the custom event handler is registered. > + > +RETURN VALUE > +------------ > +The _tep_register_event_handler()_ function returns _TEP_REGISTER_SUCCESS_ > +if the new handler is registered successfully or > +_TEP_REGISTER_SUCCESS_OVERWRITE_ if an existing handler is overwritten. > +If there is not enough memory to complete the registration, > +TEP_ERRNO__MEM_ALLOC_FAILED is returned. > + > +The _tep_unregister_event_handler()_ function returns 0 if _func_ was removed > +successful or, -1 if the event was not found. > + > +The _tep_event_handler_func_ should return -1 in case of an error, > +or 0 otherwise. > + > +EXAMPLE > +------- > +[source,c] > +-- > +#include <event-parse.h> > +#include <trace-seq.h> > +... > +struct tep_handle *tep = tep_alloc(); > +... > +int custom_event_handler(struct trace_seq *s, struct tep_record *record, > + struct tep_event *event, void *context) > +{ > + trace_seq_printf(s, "kvm_exit event"); We should use a more concrete example. One that does something with the event. Feel free to use one of the plugin calls. -- Steve > + return 0; > +} > +... > + if (tep_register_event_handler(tep, -1, "kvm", "kvm_exit", > + custom_event_handler, NULL)) { > + /* Failed to register the handler for event "kvm_exit", > "kvm" system */ > + } > +... > + if (tep_unregister_event_handler(pevent, -1, "kvm", > "kvm_exit", > + custom_event_handler, > NULL) != ) { > + /* Failed to unregister the handler for event "kvm_exit", > "kvm" system */ > + } > + > +-- > + > +FILES > +----- > +[verse] > +-- > +*event-parse.h* > + Header file to include in order to have access to the > library APIs. +*trace-seq.h* > + Header file to include in order to have access to trace > sequences > + related APIs. Trace sequences are used to allow a function > to call > + several other functions to create a string of data to use. > +*-ltraceevent* > + Linker switch to add when building a program that uses the > library. +-- > + > +SEE ALSO > +-------- > +_libtraceevent(3)_, _trace-cmd(1)_ > + > +AUTHOR > +------ > +[verse] > +-- > +*Steven Rostedt* <rostedt@goodmis.org>, author of *libtraceevent*. > +*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com>, author of this man > page. +-- > +REPORTING BUGS > +-------------- > +Report bugs to <linux-trace-devel@vger.kernel.org> > + > +LICENSE > +------- > +libtraceevent is Free Software licensed under the GNU LGPL 2.1 > + > +RESOURCES > +--------- > +https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
diff --git a/tools/lib/traceevent/Documentation/libtraceevent-reg_event_handler.txt b/tools/lib/traceevent/Documentation/libtraceevent-reg_event_handler.txt new file mode 100644 index 000000000000..8b1b75da7628 --- /dev/null +++ b/tools/lib/traceevent/Documentation/libtraceevent-reg_event_handler.txt @@ -0,0 +1,131 @@ +libtraceevent(3) +================ + +NAME +---- +tep_register_event_handler, tep_unregister_event_handler - Register / +unregisters a callback function to parse an event information. + +SYNOPSIS +-------- +[verse] +-- +*#include <event-parse.h>* + +enum *tep_reg_handler* { + _TEP_REGISTER_SUCCESS_, + _TEP_REGISTER_SUCCESS_OVERWRITE_, +}; + +int *tep_register_event_handler*(struct tep_handle pass:[*]_tep_, int _id_, const char pass:[*]_sys_name_, const char pass:[*]_event_name_, tep_event_handler_func _func_, void pass:[*]_context_); +int *tep_unregister_event_handler*(struct tep_handle pass:[*]tep, int id, const char pass:[*]sys_name, const char pass:[*]event_name, tep_event_handler_func func, void pass:[*]_context_); + +typedef int (*pass:[*]tep_event_handler_func*)(struct trace_seq pass:[*]s, struct tep_record pass:[*]record, struct tep_event pass:[*]event, void pass:[*]context); +-- + +DESCRIPTION +----------- +The _tep_register_event_handler()_ function registers a handler function, +which is going to be called to parse the information for a given event. +The _tep_ argument is the trace event parser context. The _id_ argument is +the id of the event. The _sys_name_ argument is the name of the system, +the event belongs to. The _event_name_ argument is the name of the event. +If _id_ is >= 0, it is used to find the event, otherwise _sys_name_ and +_event_name_ are used. The _func_ is a pointer to the function, which is going +to be called to parse the event information. The _context_ argument is a pointer +to the context data, which will be passed to the _func_. If a handler function +for the same event is already registered, it will be overridden with the new +one. This mechanism allows a developer to override the parsing of a given event. +If for some reason the default print format is not sufficient, the developer +can register a function for an event to be used to parse the data instead. + +The _tep_unregister_event_handler()_ function unregisters the handler function, +previously registered with _tep_register_event_handler()_. The _tep_ argument +is the trace event parser context. The _id_, _sys_name_, _event_name_, _func_, +and _context_ are the same arguments, as when the callback function _func_ was +registered. + +The _tep_event_handler_func_ is the type of the custom event handler +function. The _s_ argument is the trace sequence, it can be used to create a +custom string, describing the event. A _record_ to get the event from is passed +as input parameter and also the _event_ - the handle to the record's event. The +_context_ is custom context, set when the custom event handler is registered. + +RETURN VALUE +------------ +The _tep_register_event_handler()_ function returns _TEP_REGISTER_SUCCESS_ +if the new handler is registered successfully or +_TEP_REGISTER_SUCCESS_OVERWRITE_ if an existing handler is overwritten. +If there is not enough memory to complete the registration, +TEP_ERRNO__MEM_ALLOC_FAILED is returned. + +The _tep_unregister_event_handler()_ function returns 0 if _func_ was removed +successful or, -1 if the event was not found. + +The _tep_event_handler_func_ should return -1 in case of an error, +or 0 otherwise. + +EXAMPLE +------- +[source,c] +-- +#include <event-parse.h> +#include <trace-seq.h> +... +struct tep_handle *tep = tep_alloc(); +... +int custom_event_handler(struct trace_seq *s, struct tep_record *record, + struct tep_event *event, void *context) +{ + trace_seq_printf(s, "kvm_exit event"); + return 0; +} +... + if (tep_register_event_handler(tep, -1, "kvm", "kvm_exit", + custom_event_handler, NULL)) { + /* Failed to register the handler for event "kvm_exit", "kvm" system */ + } +... + if (tep_unregister_event_handler(pevent, -1, "kvm", "kvm_exit", + custom_event_handler, NULL) != ) { + /* Failed to unregister the handler for event "kvm_exit", "kvm" system */ + } + +-- + +FILES +----- +[verse] +-- +*event-parse.h* + Header file to include in order to have access to the library APIs. +*trace-seq.h* + Header file to include in order to have access to trace sequences + related APIs. Trace sequences are used to allow a function to call + several other functions to create a string of data to use. +*-ltraceevent* + Linker switch to add when building a program that uses the library. +-- + +SEE ALSO +-------- +_libtraceevent(3)_, _trace-cmd(1)_ + +AUTHOR +------ +[verse] +-- +*Steven Rostedt* <rostedt@goodmis.org>, author of *libtraceevent*. +*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com>, author of this man page. +-- +REPORTING BUGS +-------------- +Report bugs to <linux-trace-devel@vger.kernel.org> + +LICENSE +------- +libtraceevent is Free Software licensed under the GNU LGPL 2.1 + +RESOURCES +--------- +https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Create man pages for libtraceevent APIs: tep_register_event_handler() tep_unregister_event_handler() Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com> --- .../libtraceevent-reg_event_handler.txt | 131 ++++++++++++++++++ 1 file changed, 131 insertions(+) create mode 100644 tools/lib/traceevent/Documentation/libtraceevent-reg_event_handler.txt