// SPDX-License-Identifier: GPL-2.0 /* * trace_events_trigger - trace event triggers * * Copyright (C) 2013 Tom Zanussi <[email protected]> */ #include <linux/security.h> #include <linux/module.h> #include <linux/ctype.h> #include <linux/mutex.h> #include <linux/slab.h> #include <linux/rculist.h> #include "trace.h" static LIST_HEAD(trigger_commands); static DEFINE_MUTEX(trigger_cmd_mutex); void trigger_data_free(struct event_trigger_data *data) { … } /** * event_triggers_call - Call triggers associated with a trace event * @file: The trace_event_file associated with the event * @buffer: The ring buffer that the event is being written to * @rec: The trace entry for the event, NULL for unconditional invocation * @event: The event meta data in the ring buffer * * For each trigger associated with an event, invoke the trigger * function registered with the associated trigger command. If rec is * non-NULL, it means that the trigger requires further processing and * shouldn't be unconditionally invoked. If rec is non-NULL and the * trigger has a filter associated with it, rec will checked against * the filter and if the record matches the trigger will be invoked. * If the trigger is a 'post_trigger', meaning it shouldn't be invoked * in any case until the current event is written, the trigger * function isn't invoked but the bit associated with the deferred * trigger is set in the return value. * * Returns an enum event_trigger_type value containing a set bit for * any trigger that should be deferred, ETT_NONE if nothing to defer. * * Called from tracepoint handlers (with rcu_read_lock_sched() held). * * Return: an enum event_trigger_type value containing a set bit for * any trigger that should be deferred, ETT_NONE if nothing to defer. */ enum event_trigger_type event_triggers_call(struct trace_event_file *file, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { … } EXPORT_SYMBOL_GPL(…); bool __trace_trigger_soft_disabled(struct trace_event_file *file) { … } EXPORT_SYMBOL_GPL(…); /** * event_triggers_post_call - Call 'post_triggers' for a trace event * @file: The trace_event_file associated with the event * @tt: enum event_trigger_type containing a set bit for each trigger to invoke * * For each trigger associated with an event, invoke the trigger * function registered with the associated trigger command, if the * corresponding bit is set in the tt enum passed into this function. * See @event_triggers_call for details on how those bits are set. * * Called from tracepoint handlers (with rcu_read_lock_sched() held). */ void event_triggers_post_call(struct trace_event_file *file, enum event_trigger_type tt) { … } EXPORT_SYMBOL_GPL(…); #define SHOW_AVAILABLE_TRIGGERS … static void *trigger_next(struct seq_file *m, void *t, loff_t *pos) { … } static bool check_user_trigger(struct trace_event_file *file) { … } static void *trigger_start(struct seq_file *m, loff_t *pos) { … } static void trigger_stop(struct seq_file *m, void *t) { … } static int trigger_show(struct seq_file *m, void *v) { … } static const struct seq_operations event_triggers_seq_ops = …; static int event_trigger_regex_open(struct inode *inode, struct file *file) { … } int trigger_process_regex(struct trace_event_file *file, char *buff) { … } static ssize_t event_trigger_regex_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos) { … } static int event_trigger_regex_release(struct inode *inode, struct file *file) { … } static ssize_t event_trigger_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { … } static int event_trigger_open(struct inode *inode, struct file *filp) { … } static int event_trigger_release(struct inode *inode, struct file *file) { … } const struct file_operations event_trigger_fops = …; /* * Currently we only register event commands from __init, so mark this * __init too. */ __init int register_event_command(struct event_command *cmd) { … } /* * Currently we only unregister event commands from __init, so mark * this __init too. */ __init int unregister_event_command(struct event_command *cmd) { … } /** * event_trigger_print - Generic event_trigger_ops @print implementation * @name: The name of the event trigger * @m: The seq_file being printed to * @data: Trigger-specific data * @filter_str: filter_str to print, if present * * Common implementation for event triggers to print themselves. * * Usually wrapped by a function that simply sets the @name of the * trigger command and then invokes this. * * Return: 0 on success, errno otherwise */ static int event_trigger_print(const char *name, struct seq_file *m, void *data, char *filter_str) { … } /** * event_trigger_init - Generic event_trigger_ops @init implementation * @data: Trigger-specific data * * Common implementation of event trigger initialization. * * Usually used directly as the @init method in event trigger * implementations. * * Return: 0 on success, errno otherwise */ int event_trigger_init(struct event_trigger_data *data) { … } /** * event_trigger_free - Generic event_trigger_ops @free implementation * @data: Trigger-specific data * * Common implementation of event trigger de-initialization. * * Usually used directly as the @free method in event trigger * implementations. */ static void event_trigger_free(struct event_trigger_data *data) { … } int trace_event_trigger_enable_disable(struct trace_event_file *file, int trigger_enable) { … } /** * clear_event_triggers - Clear all triggers associated with a trace array * @tr: The trace array to clear * * For each trigger, the triggering event has its tm_ref decremented * via trace_event_trigger_enable_disable(), and any associated event * (in the case of enable/disable_event triggers) will have its sm_ref * decremented via free()->trace_event_enable_disable(). That * combination effectively reverses the soft-mode/trigger state added * by trigger registration. * * Must be called with event_mutex held. */ void clear_event_triggers(struct trace_array *tr) { … } /** * update_cond_flag - Set or reset the TRIGGER_COND bit * @file: The trace_event_file associated with the event * * If an event has triggers and any of those triggers has a filter or * a post_trigger, trigger invocation needs to be deferred until after * the current event has logged its data, and the event should have * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be * cleared. */ void update_cond_flag(struct trace_event_file *file) { … } /** * register_trigger - Generic event_command @reg implementation * @glob: The raw string used to register the trigger * @data: Trigger-specific data to associate with the trigger * @file: The trace_event_file associated with the event * * Common implementation for event trigger registration. * * Usually used directly as the @reg method in event command * implementations. * * Return: 0 on success, errno otherwise */ static int register_trigger(char *glob, struct event_trigger_data *data, struct trace_event_file *file) { … } /* * True if the trigger was found and unregistered, else false. */ static bool try_unregister_trigger(char *glob, struct event_trigger_data *test, struct trace_event_file *file) { … } /** * unregister_trigger - Generic event_command @unreg implementation * @glob: The raw string used to register the trigger * @test: Trigger-specific data used to find the trigger to remove * @file: The trace_event_file associated with the event * * Common implementation for event trigger unregistration. * * Usually used directly as the @unreg method in event command * implementations. */ static void unregister_trigger(char *glob, struct event_trigger_data *test, struct trace_event_file *file) { … } /* * Event trigger parsing helper functions. * * These functions help make it easier to write an event trigger * parsing function i.e. the struct event_command.parse() callback * function responsible for parsing and registering a trigger command * written to the 'trigger' file. * * A trigger command (or just 'trigger' for short) takes the form: * [trigger] [if filter] * * The struct event_command.parse() callback (and other struct * event_command functions) refer to several components of a trigger * command. Those same components are referenced by the event trigger * parsing helper functions defined below. These components are: * * cmd - the trigger command name * glob - the trigger command name optionally prefaced with '!' * param_and_filter - text following cmd and ':' * param - text following cmd and ':' and stripped of filter * filter - the optional filter text following (and including) 'if' * * To illustrate the use of these componenents, here are some concrete * examples. For the following triggers: * * echo 'traceon:5 if pid == 0' > trigger * - 'traceon' is both cmd and glob * - '5 if pid == 0' is the param_and_filter * - '5' is the param * - 'if pid == 0' is the filter * * echo 'enable_event:sys:event:n' > trigger * - 'enable_event' is both cmd and glob * - 'sys:event:n' is the param_and_filter * - 'sys:event:n' is the param * - there is no filter * * echo 'hist:keys=pid if prio > 50' > trigger * - 'hist' is both cmd and glob * - 'keys=pid if prio > 50' is the param_and_filter * - 'keys=pid' is the param * - 'if prio > 50' is the filter * * echo '!enable_event:sys:event:n' > trigger * - 'enable_event' the cmd * - '!enable_event' is the glob * - 'sys:event:n' is the param_and_filter * - 'sys:event:n' is the param * - there is no filter * * echo 'traceoff' > trigger * - 'traceoff' is both cmd and glob * - there is no param_and_filter * - there is no param * - there is no filter * * There are a few different categories of event trigger covered by * these helpers: * * - triggers that don't require a parameter e.g. traceon * - triggers that do require a parameter e.g. enable_event and hist * - triggers that though they may not require a param may support an * optional 'n' param (n = number of times the trigger should fire) * e.g.: traceon:5 or enable_event:sys:event:n * - triggers that do not support an 'n' param e.g. hist * * These functions can be used or ignored as necessary - it all * depends on the complexity of the trigger, and the granularity of * the functions supported reflects the fact that some implementations * may need to customize certain aspects of their implementations and * won't need certain functions. For instance, the hist trigger * implementation doesn't use event_trigger_separate_filter() because * it has special requirements for handling the filter. */ /** * event_trigger_check_remove - check whether an event trigger specifies remove * @glob: The trigger command string, with optional remove(!) operator * * The event trigger callback implementations pass in 'glob' as a * parameter. This is the command name either with or without a * remove(!) operator. This function simply parses the glob and * determines whether the command corresponds to a trigger removal or * a trigger addition. * * Return: true if this is a remove command, false otherwise */ bool event_trigger_check_remove(const char *glob) { … } /** * event_trigger_empty_param - check whether the param is empty * @param: The trigger param string * * The event trigger callback implementations pass in 'param' as a * parameter. This corresponds to the string following the command * name minus the command name. This function can be called by a * callback implementation for any command that requires a param; a * callback that doesn't require a param can ignore it. * * Return: true if this is an empty param, false otherwise */ bool event_trigger_empty_param(const char *param) { … } /** * event_trigger_separate_filter - separate an event trigger from a filter * @param_and_filter: String containing trigger and possibly filter * @param: outparam, will be filled with a pointer to the trigger * @filter: outparam, will be filled with a pointer to the filter * @param_required: Specifies whether or not the param string is required * * Given a param string of the form '[trigger] [if filter]', this * function separates the filter from the trigger and returns the * trigger in @param and the filter in @filter. Either the @param * or the @filter may be set to NULL by this function - if not set to * NULL, they will contain strings corresponding to the trigger and * filter. * * There are two cases that need to be handled with respect to the * passed-in param: either the param is required, or it is not * required. If @param_required is set, and there's no param, it will * return -EINVAL. If @param_required is not set and there's a param * that starts with a number, that corresponds to the case of a * trigger with :n (n = number of times the trigger should fire) and * the parsing continues normally; otherwise the function just returns * and assumes param just contains a filter and there's nothing else * to do. * * Return: 0 on success, errno otherwise */ int event_trigger_separate_filter(char *param_and_filter, char **param, char **filter, bool param_required) { … } /** * event_trigger_alloc - allocate and init event_trigger_data for a trigger * @cmd_ops: The event_command operations for the trigger * @cmd: The cmd string * @param: The param string * @private_data: User data to associate with the event trigger * * Allocate an event_trigger_data instance and initialize it. The * @cmd_ops are used along with the @cmd and @param to get the * trigger_ops to assign to the event_trigger_data. @private_data can * also be passed in and associated with the event_trigger_data. * * Use event_trigger_free() to free an event_trigger_data object. * * Return: The trigger_data object success, NULL otherwise */ struct event_trigger_data *event_trigger_alloc(struct event_command *cmd_ops, char *cmd, char *param, void *private_data) { … } /** * event_trigger_parse_num - parse and return the number param for a trigger * @param: The param string * @trigger_data: The trigger_data for the trigger * * Parse the :n (n = number of times the trigger should fire) param * and set the count variable in the trigger_data to the parsed count. * * Return: 0 on success, errno otherwise */ int event_trigger_parse_num(char *param, struct event_trigger_data *trigger_data) { … } /** * event_trigger_set_filter - set an event trigger's filter * @cmd_ops: The event_command operations for the trigger * @file: The event file for the trigger's event * @param: The string containing the filter * @trigger_data: The trigger_data for the trigger * * Set the filter for the trigger. If the filter is NULL, just return * without error. * * Return: 0 on success, errno otherwise */ int event_trigger_set_filter(struct event_command *cmd_ops, struct trace_event_file *file, char *param, struct event_trigger_data *trigger_data) { … } /** * event_trigger_reset_filter - reset an event trigger's filter * @cmd_ops: The event_command operations for the trigger * @trigger_data: The trigger_data for the trigger * * Reset the filter for the trigger to no filter. */ void event_trigger_reset_filter(struct event_command *cmd_ops, struct event_trigger_data *trigger_data) { … } /** * event_trigger_register - register an event trigger * @cmd_ops: The event_command operations for the trigger * @file: The event file for the trigger's event * @glob: The trigger command string, with optional remove(!) operator * @trigger_data: The trigger_data for the trigger * * Register an event trigger. The @cmd_ops are used to call the * cmd_ops->reg() function which actually does the registration. * * Return: 0 on success, errno otherwise */ int event_trigger_register(struct event_command *cmd_ops, struct trace_event_file *file, char *glob, struct event_trigger_data *trigger_data) { … } /** * event_trigger_unregister - unregister an event trigger * @cmd_ops: The event_command operations for the trigger * @file: The event file for the trigger's event * @glob: The trigger command string, with optional remove(!) operator * @trigger_data: The trigger_data for the trigger * * Unregister an event trigger. The @cmd_ops are used to call the * cmd_ops->unreg() function which actually does the unregistration. */ void event_trigger_unregister(struct event_command *cmd_ops, struct trace_event_file *file, char *glob, struct event_trigger_data *trigger_data) { … } /* * End event trigger parsing helper functions. */ /** * event_trigger_parse - Generic event_command @parse implementation * @cmd_ops: The command ops, used for trigger registration * @file: The trace_event_file associated with the event * @glob: The raw string used to register the trigger * @cmd: The cmd portion of the string used to register the trigger * @param_and_filter: The param and filter portion of the string used to register the trigger * * Common implementation for event command parsing and trigger * instantiation. * * Usually used directly as the @parse method in event command * implementations. * * Return: 0 on success, errno otherwise */ static int event_trigger_parse(struct event_command *cmd_ops, struct trace_event_file *file, char *glob, char *cmd, char *param_and_filter) { … } /** * set_trigger_filter - Generic event_command @set_filter implementation * @filter_str: The filter string for the trigger, NULL to remove filter * @trigger_data: Trigger-specific data * @file: The trace_event_file associated with the event * * Common implementation for event command filter parsing and filter * instantiation. * * Usually used directly as the @set_filter method in event command * implementations. * * Also used to remove a filter (if filter_str = NULL). * * Return: 0 on success, errno otherwise */ int set_trigger_filter(char *filter_str, struct event_trigger_data *trigger_data, struct trace_event_file *file) { … } static LIST_HEAD(named_triggers); /** * find_named_trigger - Find the common named trigger associated with @name * @name: The name of the set of named triggers to find the common data for * * Named triggers are sets of triggers that share a common set of * trigger data. The first named trigger registered with a given name * owns the common trigger data that the others subsequently * registered with the same name will reference. This function * returns the common trigger data associated with that first * registered instance. * * Return: the common trigger data for the given named trigger on * success, NULL otherwise. */ struct event_trigger_data *find_named_trigger(const char *name) { … } /** * is_named_trigger - determine if a given trigger is a named trigger * @test: The trigger data to test * * Return: true if 'test' is a named trigger, false otherwise. */ bool is_named_trigger(struct event_trigger_data *test) { … } /** * save_named_trigger - save the trigger in the named trigger list * @name: The name of the named trigger set * @data: The trigger data to save * * Return: 0 if successful, negative error otherwise. */ int save_named_trigger(const char *name, struct event_trigger_data *data) { … } /** * del_named_trigger - delete a trigger from the named trigger list * @data: The trigger data to delete */ void del_named_trigger(struct event_trigger_data *data) { … } static void __pause_named_trigger(struct event_trigger_data *data, bool pause) { … } /** * pause_named_trigger - Pause all named triggers with the same name * @data: The trigger data of a named trigger to pause * * Pauses a named trigger along with all other triggers having the * same name. Because named triggers share a common set of data, * pausing only one is meaningless, so pausing one named trigger needs * to pause all triggers with the same name. */ void pause_named_trigger(struct event_trigger_data *data) { … } /** * unpause_named_trigger - Un-pause all named triggers with the same name * @data: The trigger data of a named trigger to unpause * * Un-pauses a named trigger along with all other triggers having the * same name. Because named triggers share a common set of data, * unpausing only one is meaningless, so unpausing one named trigger * needs to unpause all triggers with the same name. */ void unpause_named_trigger(struct event_trigger_data *data) { … } /** * set_named_trigger_data - Associate common named trigger data * @data: The trigger data to associate * @named_data: The common named trigger to be associated * * Named triggers are sets of triggers that share a common set of * trigger data. The first named trigger registered with a given name * owns the common trigger data that the others subsequently * registered with the same name will reference. This function * associates the common trigger data from the first trigger with the * given trigger. */ void set_named_trigger_data(struct event_trigger_data *data, struct event_trigger_data *named_data) { … } struct event_trigger_data * get_named_trigger_data(struct event_trigger_data *data) { … } static void traceon_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { … } static void traceon_count_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { … } static void traceoff_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { … } static void traceoff_count_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { … } static int traceon_trigger_print(struct seq_file *m, struct event_trigger_data *data) { … } static int traceoff_trigger_print(struct seq_file *m, struct event_trigger_data *data) { … } static struct event_trigger_ops traceon_trigger_ops = …; static struct event_trigger_ops traceon_count_trigger_ops = …; static struct event_trigger_ops traceoff_trigger_ops = …; static struct event_trigger_ops traceoff_count_trigger_ops = …; static struct event_trigger_ops * onoff_get_trigger_ops(char *cmd, char *param) { … } static struct event_command trigger_traceon_cmd = …; static struct event_command trigger_traceoff_cmd = …; #ifdef CONFIG_TRACER_SNAPSHOT static void snapshot_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { … } static void snapshot_count_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { … } static int register_snapshot_trigger(char *glob, struct event_trigger_data *data, struct trace_event_file *file) { … } static void unregister_snapshot_trigger(char *glob, struct event_trigger_data *data, struct trace_event_file *file) { … } static int snapshot_trigger_print(struct seq_file *m, struct event_trigger_data *data) { … } static struct event_trigger_ops snapshot_trigger_ops = …; static struct event_trigger_ops snapshot_count_trigger_ops = …; static struct event_trigger_ops * snapshot_get_trigger_ops(char *cmd, char *param) { … } static struct event_command trigger_snapshot_cmd = …; static __init int register_trigger_snapshot_cmd(void) { … } #else static __init int register_trigger_snapshot_cmd(void) { return 0; } #endif /* CONFIG_TRACER_SNAPSHOT */ #ifdef CONFIG_STACKTRACE #ifdef CONFIG_UNWINDER_ORC /* Skip 2: * event_triggers_post_call() * trace_event_raw_event_xxx() */ #define STACK_SKIP … #else /* * Skip 4: * stacktrace_trigger() * event_triggers_post_call() * trace_event_buffer_commit() * trace_event_raw_event_xxx() */ #define STACK_SKIP … #endif static void stacktrace_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { … } static void stacktrace_count_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { … } static int stacktrace_trigger_print(struct seq_file *m, struct event_trigger_data *data) { … } static struct event_trigger_ops stacktrace_trigger_ops = …; static struct event_trigger_ops stacktrace_count_trigger_ops = …; static struct event_trigger_ops * stacktrace_get_trigger_ops(char *cmd, char *param) { … } static struct event_command trigger_stacktrace_cmd = …; static __init int register_trigger_stacktrace_cmd(void) { … } #else static __init int register_trigger_stacktrace_cmd(void) { return 0; } #endif /* CONFIG_STACKTRACE */ static __init void unregister_trigger_traceon_traceoff_cmds(void) { … } static void event_enable_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { … } static void event_enable_count_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { … } int event_enable_trigger_print(struct seq_file *m, struct event_trigger_data *data) { … } void event_enable_trigger_free(struct event_trigger_data *data) { … } static struct event_trigger_ops event_enable_trigger_ops = …; static struct event_trigger_ops event_enable_count_trigger_ops = …; static struct event_trigger_ops event_disable_trigger_ops = …; static struct event_trigger_ops event_disable_count_trigger_ops = …; int event_enable_trigger_parse(struct event_command *cmd_ops, struct trace_event_file *file, char *glob, char *cmd, char *param_and_filter) { … } int event_enable_register_trigger(char *glob, struct event_trigger_data *data, struct trace_event_file *file) { … } void event_enable_unregister_trigger(char *glob, struct event_trigger_data *test, struct trace_event_file *file) { … } static struct event_trigger_ops * event_enable_get_trigger_ops(char *cmd, char *param) { … } static struct event_command trigger_enable_cmd = …; static struct event_command trigger_disable_cmd = …; static __init void unregister_trigger_enable_disable_cmds(void) { … } static __init int register_trigger_enable_disable_cmds(void) { … } static __init int register_trigger_traceon_traceoff_cmds(void) { … } __init int register_trigger_cmds(void) { … }
Codebase Browser
linux