// SPDX-License-Identifier: GPL-2.0 /* * trace_events_trigger - trace event triggers * * Copyright (C) 2013 Tom Zanussi */ #include #include #include #include #include #include #include "trace.h" static LIST_HEAD(trigger_commands); static DEFINE_MUTEX(trigger_cmd_mutex); void trigger_data_free(struct event_trigger_data *data) { if (data->cmd_ops->set_filter) data->cmd_ops->set_filter(NULL, data, NULL); /* make sure current triggers exit before free */ tracepoint_synchronize_unregister(); kfree(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) { struct event_trigger_data *data; enum event_trigger_type tt = ETT_NONE; struct event_filter *filter; if (list_empty(&file->triggers)) return tt; list_for_each_entry_rcu(data, &file->triggers, list) { if (data->paused) continue; if (!rec) { data->ops->trigger(data, buffer, rec, event); continue; } filter = rcu_dereference_sched(data->filter); if (filter && !filter_match_preds(filter, rec)) continue; if (event_command_post_trigger(data->cmd_ops)) { tt |= data->cmd_ops->trigger_type; continue; } data->ops->trigger(data, buffer, rec, event); } return tt; } EXPORT_SYMBOL_GPL(event_triggers_call); bool __trace_trigger_soft_disabled(struct trace_event_file *file) { unsigned long eflags = file->flags; if (eflags & EVENT_FILE_FL_TRIGGER_MODE) event_triggers_call(file, NULL, NULL, NULL); if (eflags & EVENT_FILE_FL_SOFT_DISABLED) return true; if (eflags & EVENT_FILE_FL_PID_FILTER) return trace_event_ignore_this_pid(file); return false; } EXPORT_SYMBOL_GPL(__trace_trigger_soft_disabled); /** * 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) { struct event_trigger_data *data; list_for_each_entry_rcu(data, &file->triggers, list) { if (data->paused) continue; if (data->cmd_ops->trigger_type & tt) data->ops->trigger(data, NULL, NULL, NULL); } } EXPORT_SYMBOL_GPL(event_triggers_post_call); #define SHOW_AVAILABLE_TRIGGERS (void *)(1UL) static void *trigger_next(struct seq_file *m, void *t, loff_t *pos) { struct trace_event_file *event_file = event_file_data(m->private); if (t == SHOW_AVAILABLE_TRIGGERS) { (*pos)++; return NULL; } return seq_list_next(t, &event_file->triggers, pos); } static bool check_user_trigger(struct trace_event_file *file) { struct event_trigger_data *data; list_for_each_entry_rcu(data, &file->triggers, list, lockdep_is_held(&event_mutex)) { if (data->flags & EVENT_TRIGGER_FL_PROBE) continue; return true; } return false; } static void *trigger_start(struct seq_file *m, loff_t *pos) { struct trace_event_file *event_file; /* ->stop() is called even if ->start() fails */ mutex_lock(&event_mutex); event_file = event_file_data(m->private); if (unlikely(!event_file)) return ERR_PTR(-ENODEV); if (list_empty(&event_file->triggers) || !check_user_trigger(event_file)) return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL; return seq_list_start(&event_file->triggers, *pos); } static void trigger_stop(struct seq_file *m, void *t) { mutex_unlock(&event_mutex); } static int trigger_show(struct seq_file *m, void *v) { struct event_trigger_data *data; struct event_command *p; if (v == SHOW_AVAILABLE_TRIGGERS) { seq_puts(m, "# Available triggers:\n"); seq_putc(m, '#'); mutex_lock(&trigger_cmd_mutex); list_for_each_entry_reverse(p, &trigger_commands, list) seq_printf(m, " %s", p->name); seq_putc(m, '\n'); mutex_unlock(&trigger_cmd_mutex); return 0; } data = list_entry(v, struct event_trigger_data, list); data->ops->print(m, data); return 0; } static const struct seq_operations event_triggers_seq_ops = { .start = trigger_start, .next = trigger_next, .stop = trigger_stop, .show = trigger_show, }; static int event_trigger_regex_open(struct inode *inode, struct file *file) { int ret; ret = security_locked_down(LOCKDOWN_TRACEFS); if (ret) return ret; mutex_lock(&event_mutex); if (unlikely(!event_file_data(file))) { mutex_unlock(&event_mutex); return -ENODEV; } if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { struct trace_event_file *event_file; struct event_command *p; event_file = event_file_data(file); list_for_each_entry(p, &trigger_commands, list) { if (p->unreg_all) p->unreg_all(event_file); } } if (file->f_mode & FMODE_READ) { ret = seq_open(file, &event_triggers_seq_ops); if (!ret) { struct seq_file *m = file->private_data; m->private = file; } } mutex_unlock(&event_mutex); return ret; } int trigger_process_regex(struct trace_event_file *file, char *buff) { char *command, *next; struct event_command *p; int ret = -EINVAL; next = buff = skip_spaces(buff); command = strsep(&next, ": \t"); if (next) { next = skip_spaces(next); if (!*next) next = NULL; } command = (command[0] != '!') ? command : command + 1; mutex_lock(&trigger_cmd_mutex); list_for_each_entry(p, &trigger_commands, list) { if (strcmp(p->name, command) == 0) { ret = p->parse(p, file, buff, command, next); goto out_unlock; } } out_unlock: mutex_unlock(&trigger_cmd_mutex); return ret; } static ssize_t event_trigger_regex_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos) { struct trace_event_file *event_file; ssize_t ret; char *buf; if (!cnt) return 0; if (cnt >= PAGE_SIZE) return -EINVAL; buf = memdup_user_nul(ubuf, cnt); if (IS_ERR(buf)) return PTR_ERR(buf); strim(buf); mutex_lock(&event_mutex); event_file = event_file_data(file); if (unlikely(!event_file)) { mutex_unlock(&event_mutex); kfree(buf); return -ENODEV; } ret = trigger_process_regex(event_file, buf); mutex_unlock(&event_mutex); kfree(buf); if (ret < 0) goto out; *ppos += cnt; ret = cnt; out: return ret; } static int event_trigger_regex_release(struct inode *inode, struct file *file) { mutex_lock(&event_mutex); if (file->f_mode & FMODE_READ) seq_release(inode, file); mutex_unlock(&event_mutex); return 0; } static ssize_t event_trigger_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { return event_trigger_regex_write(filp, ubuf, cnt, ppos); } static int event_trigger_open(struct inode *inode, struct file *filp) { /* Checks for tracefs lockdown */ return event_trigger_regex_open(inode, filp); } static int event_trigger_release(struct inode *inode, struct file *file) { return event_trigger_regex_release(inode, file); } const struct file_operations event_trigger_fops = { .open = event_trigger_open, .read = seq_read, .write = event_trigger_write, .llseek = tracing_lseek, .release = event_trigger_release, }; /* * Currently we only register event commands from __init, so mark this * __init too. */ __init int register_event_command(struct event_command *cmd) { struct event_command *p; int ret = 0; mutex_lock(&trigger_cmd_mutex); list_for_each_entry(p, &trigger_commands, list) { if (strcmp(cmd->name, p->name) == 0) { ret = -EBUSY; goto out_unlock; } } list_add(&cmd->list, &trigger_commands); out_unlock: mutex_unlock(&trigger_cmd_mutex); return ret; } /* * Currently we only unregister event commands from __init, so mark * this __init too. */ __init int unregister_event_command(struct event_command *cmd) { struct event_command *p, *n; int ret = -ENODEV; mutex_lock(&trigger_cmd_mutex); list_for_each_entry_safe(p, n, &trigger_commands, list) { if (strcmp(cmd->name, p->name) == 0) { ret = 0; list_del_init(&p->list); goto out_unlock; } } out_unlock: mutex_unlock(&trigger_cmd_mutex); return ret; } /** * 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) { long count = (long)data; seq_puts(m, name); if (count == -1) seq_puts(m, ":unlimited"); else seq_printf(m, ":count=%ld", count); if (filter_str) seq_printf(m, " if %s\n", filter_str); else seq_putc(m, '\n'); return 0; } /** * 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) { data->ref++; return 0; } /** * 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) { if (WARN_ON_ONCE(data->ref <= 0)) return; data->ref--; if (!data->ref) trigger_data_free(data); } int trace_event_trigger_enable_disable(struct trace_event_file *file, int trigger_enable) { int ret = 0; if (trigger_enable) { if (atomic_inc_return(&file->tm_ref) > 1) return ret; set_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags); ret = trace_event_enable_disable(file, 1, 1); } else { if (atomic_dec_return(&file->tm_ref) > 0) return ret; clear_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags); ret = trace_event_enable_disable(file, 0, 1); } return ret; } /** * 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) { struct trace_event_file *file; list_for_each_entry(file, &tr->events, list) { struct event_trigger_data *data, *n; list_for_each_entry_safe(data, n, &file->triggers, list) { trace_event_trigger_enable_disable(file, 0); list_del_rcu(&data->list); if (data->ops->free) data->ops->free(data); } } } /** * 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) { struct event_trigger_data *data; bool set_cond = false; lockdep_assert_held(&event_mutex); list_for_each_entry(data, &file->triggers, list) { if (data->filter || event_command_post_trigger(data->cmd_ops) || event_command_needs_rec(data->cmd_ops)) { set_cond = true; break; } } if (set_cond) set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags); else clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags); } /** * 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) { struct event_trigger_data *test; int ret = 0; lockdep_assert_held(&event_mutex); list_for_each_entry(test, &file->triggers, list) { if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) { ret = -EEXIST; goto out; } } if (data->ops->init) { ret = data->ops->init(data); if (ret < 0) goto out; } list_add_rcu(&data->list, &file->triggers); update_cond_flag(file); ret = trace_event_trigger_enable_disable(file, 1); if (ret < 0) { list_del_rcu(&data->list); update_cond_flag(file); } out: return ret; } /** * 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) { struct event_trigger_data *data = NULL, *iter; lockdep_assert_held(&event_mutex); list_for_each_entry(iter, &file->triggers, list) { if (iter->cmd_ops->trigger_type == test->cmd_ops->trigger_type) { data = iter; list_del_rcu(&data->list); trace_event_trigger_enable_disable(file, 0); update_cond_flag(file); break; } } if (data && data->ops->free) data->ops->free(data); } /* * 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) { return (glob && glob[0] == '!') ? true : false; } /** * 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) { return !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) { int ret = 0; *param = *filter = NULL; if (!param_and_filter) { if (param_required) ret = -EINVAL; goto out; } /* * Here we check for an optional param. The only legal * optional param is :n, and if that's the case, continue * below. Otherwise we assume what's left is a filter and * return it as the filter string for the caller to deal with. */ if (!param_required && param_and_filter && !isdigit(param_and_filter[0])) { *filter = param_and_filter; goto out; } /* * Separate the param from the filter (param [if filter]). * Here we have either an optional :n param or a required * param and an optional filter. */ *param = strsep(¶m_and_filter, " \t"); /* * Here we have a filter, though it may be empty. */ if (param_and_filter) { *filter = skip_spaces(param_and_filter); if (!**filter) *filter = NULL; } out: return ret; } /** * 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) { struct event_trigger_data *trigger_data; struct event_trigger_ops *trigger_ops; trigger_ops = cmd_ops->get_trigger_ops(cmd, param); trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL); if (!trigger_data) return NULL; trigger_data->count = -1; trigger_data->ops = trigger_ops; trigger_data->cmd_ops = cmd_ops; trigger_data->private_data = private_data; INIT_LIST_HEAD(&trigger_data->list); INIT_LIST_HEAD(&trigger_data->named_list); RCU_INIT_POINTER(trigger_data->filter, NULL); return trigger_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) { char *number; int ret = 0; if (param) { number = strsep(¶m, ":"); if (!strlen(number)) return -EINVAL; /* * We use the callback data field (which is a pointer) * as our counter. */ ret = kstrtoul(number, 0, &trigger_data->count); } return ret; } /** * 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) { if (param && cmd_ops->set_filter) return cmd_ops->set_filter(param, trigger_data, file); return 0; } /** * 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) { if (cmd_ops->set_filter) cmd_ops->set_filter(NULL, trigger_data, NULL); } /** * 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) { return cmd_ops->reg(glob, trigger_data, file); } /** * 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) { cmd_ops->unreg(glob, trigger_data, file); } /* * 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) { struct event_trigger_data *trigger_data; char *param, *filter; bool remove; int ret; remove = event_trigger_check_remove(glob); ret = event_trigger_separate_filter(param_and_filter, ¶m, &filter, false); if (ret) return ret; ret = -ENOMEM; trigger_data = event_trigger_alloc(cmd_ops, cmd, param, file); if (!trigger_data) goto out; if (remove) { event_trigger_unregister(cmd_ops, file, glob+1, trigger_data); kfree(trigger_data); ret = 0; goto out; } ret = event_trigger_parse_num(param, trigger_data); if (ret) goto out_free; ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data); if (ret < 0) goto out_free; /* Up the trigger_data count to make sure reg doesn't free it on failure */ event_trigger_init(trigger_data); ret = event_trigger_register(cmd_ops, file, glob, trigger_data); if (ret) goto out_free; /* Down the counter of trigger_data or free it if not used anymore */ event_trigger_free(trigger_data); out: return ret; out_free: event_trigger_reset_filter(cmd_ops, trigger_data); kfree(trigger_data); goto out; } /** * 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) { struct event_trigger_data *data = trigger_data; struct event_filter *filter = NULL, *tmp; int ret = -EINVAL; char *s; if (!filter_str) /* clear the current filter */ goto assign; s = strsep(&filter_str, " \t"); if (!strlen(s) || strcmp(s, "if") != 0) goto out; if (!filter_str) goto out; /* The filter is for the 'trigger' event, not the triggered event */ ret = create_event_filter(file->tr, file->event_call, filter_str, true, &filter); /* Only enabled set_str for error handling */ if (filter) { kfree(filter->filter_string); filter->filter_string = NULL; } /* * If create_event_filter() fails, filter still needs to be freed. * Which the calling code will do with data->filter. */ assign: tmp = rcu_access_pointer(data->filter); rcu_assign_pointer(data->filter, filter); if (tmp) { /* * Make sure the call is done with the filter. * It is possible that a filter could fail at boot up, * and then this path will be called. Avoid the synchronization * in that case. */ if (system_state != SYSTEM_BOOTING) tracepoint_synchronize_unregister(); free_event_filter(tmp); } kfree(data->filter_str); data->filter_str = NULL; if (filter_str) { data->filter_str = kstrdup(filter_str, GFP_KERNEL); if (!data->filter_str) { free_event_filter(rcu_access_pointer(data->filter)); data->filter = NULL; ret = -ENOMEM; } } out: return ret; } 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) { struct event_trigger_data *data; if (!name) return NULL; list_for_each_entry(data, &named_triggers, named_list) { if (data->named_data) continue; if (strcmp(data->name, name) == 0) return data; } return NULL; } /** * 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) { struct event_trigger_data *data; list_for_each_entry(data, &named_triggers, named_list) { if (test == data) return true; } return false; } /** * 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) { data->name = kstrdup(name, GFP_KERNEL); if (!data->name) return -ENOMEM; list_add(&data->named_list, &named_triggers); return 0; } /** * 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) { kfree(data->name); data->name = NULL; list_del(&data->named_list); } static void __pause_named_trigger(struct event_trigger_data *data, bool pause) { struct event_trigger_data *test; list_for_each_entry(test, &named_triggers, named_list) { if (strcmp(test->name, data->name) == 0) { if (pause) { test->paused_tmp = test->paused; test->paused = true; } else { test->paused = test->paused_tmp; } } } } /** * 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) { __pause_named_trigger(data, true); } /** * 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) { __pause_named_trigger(data, false); } /** * 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) { data->named_data = named_data; } struct event_trigger_data * get_named_trigger_data(struct event_trigger_data *data) { return data->named_data; } static void traceon_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { struct trace_event_file *file = data->private_data; if (file) { if (tracer_tracing_is_on(file->tr)) return; tracer_tracing_on(file->tr); return; } if (tracing_is_on()) return; tracing_on(); } static void traceon_count_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { struct trace_event_file *file = data->private_data; if (file) { if (tracer_tracing_is_on(file->tr)) return; } else { if (tracing_is_on()) return; } if (!data->count) return; if (data->count != -1) (data->count)--; if (file) tracer_tracing_on(file->tr); else tracing_on(); } static void traceoff_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { struct trace_event_file *file = data->private_data; if (file) { if (!tracer_tracing_is_on(file->tr)) return; tracer_tracing_off(file->tr); return; } if (!tracing_is_on()) return; tracing_off(); } static void traceoff_count_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { struct trace_event_file *file = data->private_data; if (file) { if (!tracer_tracing_is_on(file->tr)) return; } else { if (!tracing_is_on()) return; } if (!data->count) return; if (data->count != -1) (data->count)--; if (file) tracer_tracing_off(file->tr); else tracing_off(); } static int traceon_trigger_print(struct seq_file *m, struct event_trigger_data *data) { return event_trigger_print("traceon", m, (void *)data->count, data->filter_str); } static int traceoff_trigger_print(struct seq_file *m, struct event_trigger_data *data) { return event_trigger_print("traceoff", m, (void *)data->count, data->filter_str); } static struct event_trigger_ops traceon_trigger_ops = { .trigger = traceon_trigger, .print = traceon_trigger_print, .init = event_trigger_init, .free = event_trigger_free, }; static struct event_trigger_ops traceon_count_trigger_ops = { .trigger = traceon_count_trigger, .print = traceon_trigger_print, .init = event_trigger_init, .free = event_trigger_free, }; static struct event_trigger_ops traceoff_trigger_ops = { .trigger = traceoff_trigger, .print = traceoff_trigger_print, .init = event_trigger_init, .free = event_trigger_free, }; static struct event_trigger_ops traceoff_count_trigger_ops = { .trigger = traceoff_count_trigger, .print = traceoff_trigger_print, .init = event_trigger_init, .free = event_trigger_free, }; static struct event_trigger_ops * onoff_get_trigger_ops(char *cmd, char *param) { struct event_trigger_ops *ops; /* we register both traceon and traceoff to this callback */ if (strcmp(cmd, "traceon") == 0) ops = param ? &traceon_count_trigger_ops : &traceon_trigger_ops; else ops = param ? &traceoff_count_trigger_ops : &traceoff_trigger_ops; return ops; } static struct event_command trigger_traceon_cmd = { .name = "traceon", .trigger_type = ETT_TRACE_ONOFF, .parse = event_trigger_parse, .reg = register_trigger, .unreg = unregister_trigger, .get_trigger_ops = onoff_get_trigger_ops, .set_filter = set_trigger_filter, }; static struct event_command trigger_traceoff_cmd = { .name = "traceoff", .trigger_type = ETT_TRACE_ONOFF, .flags = EVENT_CMD_FL_POST_TRIGGER, .parse = event_trigger_parse, .reg = register_trigger, .unreg = unregister_trigger, .get_trigger_ops = onoff_get_trigger_ops, .set_filter = set_trigger_filter, }; #ifdef CONFIG_TRACER_SNAPSHOT static void snapshot_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { struct trace_event_file *file = data->private_data; if (file) tracing_snapshot_instance(file->tr); else tracing_snapshot(); } static void snapshot_count_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { if (!data->count) return; if (data->count != -1) (data->count)--; snapshot_trigger(data, buffer, rec, event); } static int register_snapshot_trigger(char *glob, struct event_trigger_data *data, struct trace_event_file *file) { int ret = tracing_alloc_snapshot_instance(file->tr); if (ret < 0) return ret; return register_trigger(glob, data, file); } static int snapshot_trigger_print(struct seq_file *m, struct event_trigger_data *data) { return event_trigger_print("snapshot", m, (void *)data->count, data->filter_str); } static struct event_trigger_ops snapshot_trigger_ops = { .trigger = snapshot_trigger, .print = snapshot_trigger_print, .init = event_trigger_init, .free = event_trigger_free, }; static struct event_trigger_ops snapshot_count_trigger_ops = { .trigger = snapshot_count_trigger, .print = snapshot_trigger_print, .init = event_trigger_init, .free = event_trigger_free, }; static struct event_trigger_ops * snapshot_get_trigger_ops(char *cmd, char *param) { return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops; } static struct event_command trigger_snapshot_cmd = { .name = "snapshot", .trigger_type = ETT_SNAPSHOT, .parse = event_trigger_parse, .reg = register_snapshot_trigger, .unreg = unregister_trigger, .get_trigger_ops = snapshot_get_trigger_ops, .set_filter = set_trigger_filter, }; static __init int register_trigger_snapshot_cmd(void) { int ret; ret = register_event_command(&trigger_snapshot_cmd); WARN_ON(ret < 0); return ret; } #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 2 #else /* * Skip 4: * stacktrace_trigger() * event_triggers_post_call() * trace_event_buffer_commit() * trace_event_raw_event_xxx() */ #define STACK_SKIP 4 #endif static void stacktrace_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { struct trace_event_file *file = data->private_data; if (file) __trace_stack(file->tr, tracing_gen_ctx(), STACK_SKIP); else trace_dump_stack(STACK_SKIP); } static void stacktrace_count_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { if (!data->count) return; if (data->count != -1) (data->count)--; stacktrace_trigger(data, buffer, rec, event); } static int stacktrace_trigger_print(struct seq_file *m, struct event_trigger_data *data) { return event_trigger_print("stacktrace", m, (void *)data->count, data->filter_str); } static struct event_trigger_ops stacktrace_trigger_ops = { .trigger = stacktrace_trigger, .print = stacktrace_trigger_print, .init = event_trigger_init, .free = event_trigger_free, }; static struct event_trigger_ops stacktrace_count_trigger_ops = { .trigger = stacktrace_count_trigger, .print = stacktrace_trigger_print, .init = event_trigger_init, .free = event_trigger_free, }; static struct event_trigger_ops * stacktrace_get_trigger_ops(char *cmd, char *param) { return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops; } static struct event_command trigger_stacktrace_cmd = { .name = "stacktrace", .trigger_type = ETT_STACKTRACE, .flags = EVENT_CMD_FL_POST_TRIGGER, .parse = event_trigger_parse, .reg = register_trigger, .unreg = unregister_trigger, .get_trigger_ops = stacktrace_get_trigger_ops, .set_filter = set_trigger_filter, }; static __init int register_trigger_stacktrace_cmd(void) { int ret; ret = register_event_command(&trigger_stacktrace_cmd); WARN_ON(ret < 0); return ret; } #else static __init int register_trigger_stacktrace_cmd(void) { return 0; } #endif /* CONFIG_STACKTRACE */ static __init void unregister_trigger_traceon_traceoff_cmds(void) { unregister_event_command(&trigger_traceon_cmd); unregister_event_command(&trigger_traceoff_cmd); } static void event_enable_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { struct enable_trigger_data *enable_data = data->private_data; if (enable_data->enable) clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags); else set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags); } static void event_enable_count_trigger(struct event_trigger_data *data, struct trace_buffer *buffer, void *rec, struct ring_buffer_event *event) { struct enable_trigger_data *enable_data = data->private_data; if (!data->count) return; /* Skip if the event is in a state we want to switch to */ if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED)) return; if (data->count != -1) (data->count)--; event_enable_trigger(data, buffer, rec, event); } int event_enable_trigger_print(struct seq_file *m, struct event_trigger_data *data) { struct enable_trigger_data *enable_data = data->private_data; seq_printf(m, "%s:%s:%s", enable_data->hist ? (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) : (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR), enable_data->file->event_call->class->system, trace_event_name(enable_data->file->event_call)); if (data->count == -1) seq_puts(m, ":unlimited"); else seq_printf(m, ":count=%ld", data->count); if (data->filter_str) seq_printf(m, " if %s\n", data->filter_str); else seq_putc(m, '\n'); return 0; } void event_enable_trigger_free(struct event_trigger_data *data) { struct enable_trigger_data *enable_data = data->private_data; if (WARN_ON_ONCE(data->ref <= 0)) return; data->ref--; if (!data->ref) { /* Remove the SOFT_MODE flag */ trace_event_enable_disable(enable_data->file, 0, 1); trace_event_put_ref(enable_data->file->event_call); trigger_data_free(data); kfree(enable_data); } } static struct event_trigger_ops event_enable_trigger_ops = { .trigger = event_enable_trigger, .print = event_enable_trigger_print, .init = event_trigger_init, .free = event_enable_trigger_free, }; static struct event_trigger_ops event_enable_count_trigger_ops = { .trigger = event_enable_count_trigger, .print = event_enable_trigger_print, .init = event_trigger_init, .free = event_enable_trigger_free, }; static struct event_trigger_ops event_disable_trigger_ops = { .trigger = event_enable_trigger, .print = event_enable_trigger_print, .init = event_trigger_init, .free = event_enable_trigger_free, }; static struct event_trigger_ops event_disable_count_trigger_ops = { .trigger = event_enable_count_trigger, .print = event_enable_trigger_print, .init = event_trigger_init, .free = event_enable_trigger_free, }; int event_enable_trigger_parse(struct event_command *cmd_ops, struct trace_event_file *file, char *glob, char *cmd, char *param_and_filter) { struct trace_event_file *event_enable_file; struct enable_trigger_data *enable_data; struct event_trigger_data *trigger_data; struct trace_array *tr = file->tr; char *param, *filter; bool enable, remove; const char *system; const char *event; bool hist = false; int ret; remove = event_trigger_check_remove(glob); if (event_trigger_empty_param(param_and_filter)) return -EINVAL; ret = event_trigger_separate_filter(param_and_filter, ¶m, &filter, true); if (ret) return ret; system = strsep(¶m, ":"); if (!param) return -EINVAL; event = strsep(¶m, ":"); ret = -EINVAL; event_enable_file = find_event_file(tr, system, event); if (!event_enable_file) goto out; #ifdef CONFIG_HIST_TRIGGERS hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) || (strcmp(cmd, DISABLE_HIST_STR) == 0)); enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) || (strcmp(cmd, ENABLE_HIST_STR) == 0)); #else enable = strcmp(cmd, ENABLE_EVENT_STR) == 0; #endif ret = -ENOMEM; enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL); if (!enable_data) goto out; enable_data->hist = hist; enable_data->enable = enable; enable_data->file = event_enable_file; trigger_data = event_trigger_alloc(cmd_ops, cmd, param, enable_data); if (!trigger_data) { kfree(enable_data); goto out; } if (remove) { event_trigger_unregister(cmd_ops, file, glob+1, trigger_data); kfree(trigger_data); kfree(enable_data); ret = 0; goto out; } /* Up the trigger_data count to make sure nothing frees it on failure */ event_trigger_init(trigger_data); ret = event_trigger_parse_num(param, trigger_data); if (ret) goto out_free; ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data); if (ret < 0) goto out_free; /* Don't let event modules unload while probe registered */ ret = trace_event_try_get_ref(event_enable_file->event_call); if (!ret) { ret = -EBUSY; goto out_free; } ret = trace_event_enable_disable(event_enable_file, 1, 1); if (ret < 0) goto out_put; ret = event_trigger_register(cmd_ops, file, glob, trigger_data); if (ret) goto out_disable; event_trigger_free(trigger_data); out: return ret; out_disable: trace_event_enable_disable(event_enable_file, 0, 1); out_put: trace_event_put_ref(event_enable_file->event_call); out_free: event_trigger_reset_filter(cmd_ops, trigger_data); event_trigger_free(trigger_data); kfree(enable_data); goto out; } int event_enable_register_trigger(char *glob, struct event_trigger_data *data, struct trace_event_file *file) { struct enable_trigger_data *enable_data = data->private_data; struct enable_trigger_data *test_enable_data; struct event_trigger_data *test; int ret = 0; lockdep_assert_held(&event_mutex); list_for_each_entry(test, &file->triggers, list) { test_enable_data = test->private_data; if (test_enable_data && (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) && (test_enable_data->file == enable_data->file)) { ret = -EEXIST; goto out; } } if (data->ops->init) { ret = data->ops->init(data); if (ret < 0) goto out; } list_add_rcu(&data->list, &file->triggers); update_cond_flag(file); ret = trace_event_trigger_enable_disable(file, 1); if (ret < 0) { list_del_rcu(&data->list); update_cond_flag(file); } out: return ret; } void event_enable_unregister_trigger(char *glob, struct event_trigger_data *test, struct trace_event_file *file) { struct enable_trigger_data *test_enable_data = test->private_data; struct event_trigger_data *data = NULL, *iter; struct enable_trigger_data *enable_data; lockdep_assert_held(&event_mutex); list_for_each_entry(iter, &file->triggers, list) { enable_data = iter->private_data; if (enable_data && (iter->cmd_ops->trigger_type == test->cmd_ops->trigger_type) && (enable_data->file == test_enable_data->file)) { data = iter; list_del_rcu(&data->list); trace_event_trigger_enable_disable(file, 0); update_cond_flag(file); break; } } if (data && data->ops->free) data->ops->free(data); } static struct event_trigger_ops * event_enable_get_trigger_ops(char *cmd, char *param) { struct event_trigger_ops *ops; bool enable; #ifdef CONFIG_HIST_TRIGGERS enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) || (strcmp(cmd, ENABLE_HIST_STR) == 0)); #else enable = strcmp(cmd, ENABLE_EVENT_STR) == 0; #endif if (enable) ops = param ? &event_enable_count_trigger_ops : &event_enable_trigger_ops; else ops = param ? &event_disable_count_trigger_ops : &event_disable_trigger_ops; return ops; } static struct event_command trigger_enable_cmd = { .name = ENABLE_EVENT_STR, .trigger_type = ETT_EVENT_ENABLE, .parse = event_enable_trigger_parse, .reg = event_enable_register_trigger, .unreg = event_enable_unregister_trigger, .get_trigger_ops = event_enable_get_trigger_ops, .set_filter = set_trigger_filter, }; static struct event_command trigger_disable_cmd = { .name = DISABLE_EVENT_STR, .trigger_type = ETT_EVENT_ENABLE, .parse = event_enable_trigger_parse, .reg = event_enable_register_trigger, .unreg = event_enable_unregister_trigger, .get_trigger_ops = event_enable_get_trigger_ops, .set_filter = set_trigger_filter, }; static __init void unregister_trigger_enable_disable_cmds(void) { unregister_event_command(&trigger_enable_cmd); unregister_event_command(&trigger_disable_cmd); } static __init int register_trigger_enable_disable_cmds(void) { int ret; ret = register_event_command(&trigger_enable_cmd); if (WARN_ON(ret < 0)) return ret; ret = register_event_command(&trigger_disable_cmd); if (WARN_ON(ret < 0)) unregister_trigger_enable_disable_cmds(); return ret; } static __init int register_trigger_traceon_traceoff_cmds(void) { int ret; ret = register_event_command(&trigger_traceon_cmd); if (WARN_ON(ret < 0)) return ret; ret = register_event_command(&trigger_traceoff_cmd); if (WARN_ON(ret < 0)) unregister_trigger_traceon_traceoff_cmds(); return ret; } __init int register_trigger_cmds(void) { register_trigger_traceon_traceoff_cmds(); register_trigger_snapshot_cmd(); register_trigger_stacktrace_cmd(); register_trigger_enable_disable_cmds(); register_trigger_hist_enable_disable_cmds(); register_trigger_hist_cmd(); return 0; }