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Diffstat (limited to 'Documentation/libtraceevent-plugins.txt')
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diff --git a/Documentation/libtraceevent-plugins.txt b/Documentation/libtraceevent-plugins.txt new file mode 100644 index 0000000..4ca78d4 --- /dev/null +++ b/Documentation/libtraceevent-plugins.txt @@ -0,0 +1,150 @@ +libtraceevent(3) +================ + +NAME +---- +tep_load_plugins, tep_unload_plugins, tep_load_plugins_hook, tep_add_plugin_path, +tep_plugin_add_option - Load / unload traceevent plugins. + +SYNOPSIS +-------- +[verse] +-- +*#include <event-parse.h>* + +struct tep_plugin_list pass:[*]*tep_load_plugins*(struct tep_handle pass:[*]_tep_); +void *tep_unload_plugins*(struct tep_plugin_list pass:[*]_plugin_list_, struct tep_handle pass:[*]_tep_); +void *tep_load_plugins_hook*(struct tep_handle pass:[*]_tep_, const char pass:[*]_suffix_, + void (pass:[*]_load_plugin_)(struct tep_handle pass:[*]tep, + const char pass:[*]path, + const char pass:[*]name, + void pass:[*]data), + void pass:[*]_data_); +int *tep_add_plugin_path*(struct tep_handle pass:[*]tep, char pass:[*]path, + enum tep_plugin_load_priority prio); +int *tep_plugin_add_option*(const char pass:[*]_name_, const char pass:[*]_val_); +-- + +DESCRIPTION +----------- +The *tep_load_plugins()* function loads all plugins, located in the plugin +directories. The _tep_ argument is trace event parser context. +The plugin directories are : +[verse] +-- + - Directories, specified in _tep_->plugins_dir with priority TEP_PLUGIN_FIRST + - System's plugin directory, defined at the library compile time. It + depends on the library installation prefix and usually is + _(install_preffix)/lib/traceevent/plugins_ + - Directory, defined by the environment variable _TRACEEVENT_PLUGIN_DIR_ + - User's plugin directory, located at _~/.local/lib/traceevent/plugins_ + - Directories, specified in _tep_->plugins_dir with priority TEP_PLUGIN_LAST +-- +Loading of plugins can be controlled by the _tep_flags_, using the +*tep_set_flag()* API: +[verse] +-- + _TEP_DISABLE_SYS_PLUGINS_ - do not load plugins, located in + the system's plugin directory. + _TEP_DISABLE_PLUGINS_ - do not load any plugins. +-- +The *tep_set_flag()* API needs to be called before *tep_load_plugins()*, if +loading of all plugins is not the desired case. + +The *tep_unload_plugins()* function unloads the plugins, previously loaded by +*tep_load_plugins()*. The _tep_ argument is trace event parser context. The +_plugin_list_ is the list of loaded plugins, returned by +the *tep_load_plugins()* function. + +The *tep_load_plugins_hook()* function walks through all directories with plugins +and calls user specified *load_plugin()* hook for each plugin file. Only files +with given _suffix_ are considered to be plugins. The _data_ is a user specified +context, passed to *load_plugin()*. Directories and the walk order are the same +as in *tep_load_plugins()* API. + +The *tep_add_plugin_path()* functions adds additional directories with plugins in +the _tep_->plugins_dir list. It must be called before *tep_load_plugins()* in order +for the plugins from the new directories to be loaded. The _tep_ argument is +the trace event parser context. The _path_ is the full path to the new plugin +directory. The _prio_ argument specifies the loading priority order for the +new directory of plugins. The loading priority is important in case of different +versions of the same plugin located in multiple plugin directories.The last loaded +plugin wins. The priority can be: +[verse] +-- + _TEP_PLUGIN_FIRST_ - Load plugins from this directory first + _TEP_PLUGIN_LAST_ - Load plugins from this directory last +-- +Where the plugins in TEP_PLUGIN_LAST" will take precedence over the +plugins in the other directories. + +The *tep_plugin_add_option()* sets options defined by a plugin. The _name_ is the +name of the option to set to _val_. Plugins can add options to change its behavior +and *tep_plugin_add_option()* is used by the application to make those modifications. + + +RETURN VALUE +------------ +The *tep_load_plugins()* function returns a list of successfully loaded plugins, +or NULL in case no plugins are loaded. +The *tep_add_plugin_path()* function returns -1 in case of an error, 0 otherwise. + +EXAMPLE +------- +[source,c] +-- +#include <event-parse.h> +... +struct tep_handle *tep = tep_alloc(); +... +tep_add_plugin_path(tep, "~/dev_plugins", TEP_PLUGIN_LAST); +... +struct tep_plugin_list *plugins = tep_load_plugins(tep); +if (plugins == NULL) { + /* no plugins are loaded */ +} +... +tep_unload_plugins(plugins, tep); +... +void print_plugin(struct tep_handle *tep, const char *path, + const char *name, void *data) +{ + pritnf("Found libtraceevent plugin %s/%s\n", path, name); +} +... +tep_load_plugins_hook(tep, ".so", print_plugin, NULL); +... +-- + +FILES +----- +[verse] +-- +*event-parse.h* + Header file to include in order to have access to the library APIs. +*-ltraceevent* + Linker switch to add when building a program that uses the library. +-- + +SEE ALSO +-------- +*libtraceevent*(3), *trace-cmd*(1), *tep_set_flag*(3) + +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/libs/libtrace/libtraceevent.git/ |