// SPDX-License-Identifier: GPL-2.0 /* * Generic dynamic event control interface * * Copyright (C) 2018 Masami Hiramatsu <[email protected]> */ #include <linux/debugfs.h> #include <linux/kernel.h> #include <linux/list.h> #include <linux/mm.h> #include <linux/mutex.h> #include <linux/tracefs.h> #include "trace.h" #include "trace_output.h" /* for trace_event_sem */ #include "trace_dynevent.h" static DEFINE_MUTEX(dyn_event_ops_mutex); static LIST_HEAD(dyn_event_ops_list); bool trace_event_dyn_try_get_ref(struct trace_event_call *dyn_call) { … } void trace_event_dyn_put_ref(struct trace_event_call *call) { … } bool trace_event_dyn_busy(struct trace_event_call *call) { … } int dyn_event_register(struct dyn_event_operations *ops) { … } int dyn_event_release(const char *raw_command, struct dyn_event_operations *type) { … } static int create_dyn_event(const char *raw_command) { … } /* Protected by event_mutex */ LIST_HEAD(…); void *dyn_event_seq_start(struct seq_file *m, loff_t *pos) { … } void *dyn_event_seq_next(struct seq_file *m, void *v, loff_t *pos) { … } void dyn_event_seq_stop(struct seq_file *m, void *v) { … } static int dyn_event_seq_show(struct seq_file *m, void *v) { … } static const struct seq_operations dyn_event_seq_op = …; /* * dyn_events_release_all - Release all specific events * @type: the dyn_event_operations * which filters releasing events * * This releases all events which ->ops matches @type. If @type is NULL, * all events are released. * Return -EBUSY if any of them are in use, and return other errors when * it failed to free the given event. Except for -EBUSY, event releasing * process will be aborted at that point and there may be some other * releasable events on the list. */ int dyn_events_release_all(struct dyn_event_operations *type) { … } static int dyn_event_open(struct inode *inode, struct file *file) { … } static ssize_t dyn_event_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos) { … } static const struct file_operations dynamic_events_ops = …; /* Make a tracefs interface for controlling dynamic events */ static __init int init_dynamic_event(void) { … } fs_initcall(init_dynamic_event); /** * dynevent_arg_add - Add an arg to a dynevent_cmd * @cmd: A pointer to the dynevent_cmd struct representing the new event cmd * @arg: The argument to append to the current cmd * @check_arg: An (optional) pointer to a function checking arg sanity * * Append an argument to a dynevent_cmd. The argument string will be * appended to the current cmd string, followed by a separator, if * applicable. Before the argument is added, the @check_arg function, * if present, will be used to check the sanity of the current arg * string. * * The cmd string and separator should be set using the * dynevent_arg_init() before any arguments are added using this * function. * * Return: 0 if successful, error otherwise. */ int dynevent_arg_add(struct dynevent_cmd *cmd, struct dynevent_arg *arg, dynevent_check_arg_fn_t check_arg) { … } /** * dynevent_arg_pair_add - Add an arg pair to a dynevent_cmd * @cmd: A pointer to the dynevent_cmd struct representing the new event cmd * @arg_pair: The argument pair to append to the current cmd * @check_arg: An (optional) pointer to a function checking arg sanity * * Append an argument pair to a dynevent_cmd. An argument pair * consists of a left-hand-side argument and a right-hand-side * argument separated by an operator, which can be whitespace, all * followed by a separator, if applicable. This can be used to add * arguments of the form 'type variable_name;' or 'x+y'. * * The lhs argument string will be appended to the current cmd string, * followed by an operator, if applicable, followed by the rhs string, * followed finally by a separator, if applicable. Before the * argument is added, the @check_arg function, if present, will be * used to check the sanity of the current arg strings. * * The cmd strings, operator, and separator should be set using the * dynevent_arg_pair_init() before any arguments are added using this * function. * * Return: 0 if successful, error otherwise. */ int dynevent_arg_pair_add(struct dynevent_cmd *cmd, struct dynevent_arg_pair *arg_pair, dynevent_check_arg_fn_t check_arg) { … } /** * dynevent_str_add - Add a string to a dynevent_cmd * @cmd: A pointer to the dynevent_cmd struct representing the new event cmd * @str: The string to append to the current cmd * * Append a string to a dynevent_cmd. The string will be appended to * the current cmd string as-is, with nothing prepended or appended. * * Return: 0 if successful, error otherwise. */ int dynevent_str_add(struct dynevent_cmd *cmd, const char *str) { … } /** * dynevent_cmd_init - Initialize a dynevent_cmd object * @cmd: A pointer to the dynevent_cmd struct representing the cmd * @buf: A pointer to the buffer to generate the command into * @maxlen: The length of the buffer the command will be generated into * @type: The type of the cmd, checked against further operations * @run_command: The type-specific function that will actually run the command * * Initialize a dynevent_cmd. A dynevent_cmd is used to build up and * run dynamic event creation commands, such as commands for creating * synthetic and kprobe events. Before calling any of the functions * used to build the command, a dynevent_cmd object should be * instantiated and initialized using this function. * * The initialization sets things up by saving a pointer to the * user-supplied buffer and its length via the @buf and @maxlen * params, and by saving the cmd-specific @type and @run_command * params which are used to check subsequent dynevent_cmd operations * and actually run the command when complete. */ void dynevent_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen, enum dynevent_type type, dynevent_create_fn_t run_command) { … } /** * dynevent_arg_init - Initialize a dynevent_arg object * @arg: A pointer to the dynevent_arg struct representing the arg * @separator: An (optional) separator, appended after adding the arg * * Initialize a dynevent_arg object. A dynevent_arg represents an * object used to append single arguments to the current command * string. After the arg string is successfully appended to the * command string, the optional @separator is appended. If no * separator was specified when initializing the arg, a space will be * appended. */ void dynevent_arg_init(struct dynevent_arg *arg, char separator) { … } /** * dynevent_arg_pair_init - Initialize a dynevent_arg_pair object * @arg_pair: A pointer to the dynevent_arg_pair struct representing the arg * @operator: An (optional) operator, appended after adding the first arg * @separator: An (optional) separator, appended after adding the second arg * * Initialize a dynevent_arg_pair object. A dynevent_arg_pair * represents an object used to append argument pairs such as 'type * variable_name;' or 'x+y' to the current command string. An * argument pair consists of a left-hand-side argument and a * right-hand-side argument separated by an operator, which can be * whitespace, all followed by a separator, if applicable. After the * first arg string is successfully appended to the command string, * the optional @operator is appended, followed by the second arg and * optional @separator. If no separator was specified when * initializing the arg, a space will be appended. */ void dynevent_arg_pair_init(struct dynevent_arg_pair *arg_pair, char operator, char separator) { … } /** * dynevent_create - Create the dynamic event contained in dynevent_cmd * @cmd: The dynevent_cmd object containing the dynamic event creation command * * Once a dynevent_cmd object has been successfully built up via the * dynevent_cmd_init(), dynevent_arg_add() and dynevent_arg_pair_add() * functions, this function runs the final command to actually create * the event. * * Return: 0 if the event was successfully created, error otherwise. */ int dynevent_create(struct dynevent_cmd *cmd) { … } EXPORT_SYMBOL_GPL(…);
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