diff options
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/trace_dynevent.c | 240 | ||||
| -rw-r--r-- | kernel/trace/trace_dynevent.h | 33 |
2 files changed, 273 insertions, 0 deletions
diff --git a/kernel/trace/trace_dynevent.c b/kernel/trace/trace_dynevent.c index 89779eb84a07..6ffdbc4fda53 100644 --- a/kernel/trace/trace_dynevent.c +++ b/kernel/trace/trace_dynevent.c @@ -223,3 +223,243 @@ static __init int init_dynamic_event(void) return 0; } 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 + * + * 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 defined, is called. + * + * The cmd string, separator, and check_arg() function 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) +{ + int ret = 0; + int delta; + char *q; + + if (arg->check_arg) { + ret = arg->check_arg(arg); + if (ret) + return ret; + } + + q = cmd->buf + (cmd->maxlen - cmd->remaining); + + delta = snprintf(q, cmd->remaining, " %s%c", arg->str, arg->separator); + if (delta >= cmd->remaining) { + pr_err("String is too long: %s\n", arg->str); + return -E2BIG; + } + cmd->remaining -= delta; + + return ret; +} + +/** + * 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 + * + * 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, followd by the rhs string, + * followed finally by a separator, if applicable. Before anything is + * added, the check_arg() function, if defined, is called. + * + * The cmd strings, operator, separator, and check_arg() function + * 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) +{ + int ret = 0; + int delta; + char *q; + + if (arg_pair->check_arg) { + ret = arg_pair->check_arg(arg_pair); + if (ret) + return ret; + } + + q = cmd->buf + (cmd->maxlen - cmd->remaining); + + delta = snprintf(q, cmd->remaining, " %s%c", arg_pair->lhs, + arg_pair->operator); + if (delta >= cmd->remaining) { + pr_err("field string is too long: %s\n", arg_pair->lhs); + return -E2BIG; + } + cmd->remaining -= delta; q += delta; + + delta = snprintf(q, cmd->remaining, "%s%c", arg_pair->rhs, + arg_pair->separator); + if (delta >= cmd->remaining) { + pr_err("field string is too long: %s\n", arg_pair->rhs); + return -E2BIG; + } + cmd->remaining -= delta; q += delta; + + return ret; +} + +/** + * 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) +{ + int ret = 0; + int delta; + char *q; + + q = cmd->buf + (cmd->maxlen - cmd->remaining); + + delta = snprintf(q, cmd->remaining, "%s", str); + if (delta >= cmd->remaining) { + pr_err("String is too long: %s\n", str); + return -E2BIG; + } + cmd->remaining -= delta; + + return ret; +} + +/** + * 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) +{ + memset(cmd, '\0', sizeof(*cmd)); + + cmd->buf = buf; + cmd->maxlen = maxlen; + cmd->remaining = cmd->maxlen; + cmd->type = type; + cmd->run_command = run_command; +} + +/** + * dynevent_arg_init - Initialize a dynevent_arg object + * @arg: A pointer to the dynevent_arg struct representing the arg + * @check_arg: An (optional) pointer to a function checking arg sanity + * @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. The @check_arg function, if present, will be used to check + * the sanity of the current arg string (which is directly set by the + * caller). 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, + dynevent_check_arg_fn_t check_arg, + char separator) +{ + memset(arg, '\0', sizeof(*arg)); + + if (!separator) + separator = ' '; + arg->separator = separator; + + arg->check_arg = check_arg; +} + +/** + * dynevent_arg_pair_init - Initialize a dynevent_arg_pair object + * @arg_pair: A pointer to the dynevent_arg_pair struct representing the arg + * @check_arg: An (optional) pointer to a function checking arg sanity + * @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. The + * @check_arg function, if present, will be used to check the sanity + * of the current arg strings (which is directly set by the caller). + * After the first arg string is successfully appended to the command + * string, the optional @operator is appended, followed by the second + * arg and 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, + dynevent_check_arg_fn_t check_arg, + char operator, char separator) +{ + memset(arg_pair, '\0', sizeof(*arg_pair)); + + if (!operator) + operator = ' '; + arg_pair->operator = operator; + + if (!separator) + separator = ' '; + arg_pair->separator = separator; + + arg_pair->check_arg = check_arg; +} + +/** + * 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) +{ + return cmd->run_command(cmd); +} +EXPORT_SYMBOL_GPL(dynevent_create); diff --git a/kernel/trace/trace_dynevent.h b/kernel/trace/trace_dynevent.h index 46898138d2df..b593fc34c5b1 100644 --- a/kernel/trace/trace_dynevent.h +++ b/kernel/trace/trace_dynevent.h @@ -117,4 +117,37 @@ int dyn_event_release(int argc, char **argv, struct dyn_event_operations *type); #define for_each_dyn_event_safe(pos, n) \ list_for_each_entry_safe(pos, n, &dyn_event_list, list) +extern void dynevent_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen, + enum dynevent_type type, + dynevent_create_fn_t run_command); + +typedef int (*dynevent_check_arg_fn_t)(void *data); + +struct dynevent_arg { + const char *str; + char separator; /* e.g. ';', ',', or nothing */ + dynevent_check_arg_fn_t check_arg; +}; + +extern void dynevent_arg_init(struct dynevent_arg *arg, + dynevent_check_arg_fn_t check_arg, + char separator); +extern int dynevent_arg_add(struct dynevent_cmd *cmd, + struct dynevent_arg *arg); + +struct dynevent_arg_pair { + const char *lhs; + const char *rhs; + char operator; /* e.g. '=' or nothing */ + char separator; /* e.g. ';', ',', or nothing */ + dynevent_check_arg_fn_t check_arg; +}; + +extern void dynevent_arg_pair_init(struct dynevent_arg_pair *arg_pair, + dynevent_check_arg_fn_t check_arg, + char operator, char separator); +extern int dynevent_arg_pair_add(struct dynevent_cmd *cmd, + struct dynevent_arg_pair *arg_pair); +extern int dynevent_str_add(struct dynevent_cmd *cmd, const char *str); + #endif |