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
+ * @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)
+{
+ int ret = 0;
+ int delta;
+ char *q;
+
+ if (check_arg) {
+ ret = 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
+ * @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, followd 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)
+{
+ int ret = 0;
+ int delta;
+ char *q;
+
+ if (check_arg) {
+ ret = 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
+ * @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)
+{
+ memset(arg, '\0', sizeof(*arg));
+
+ if (!separator)
+ separator = ' ';
+ arg->separator = 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
+ * 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)
+{
+ memset(arg_pair, '\0', sizeof(*arg_pair));
+
+ if (!operator)
+ operator = ' ';
+ arg_pair->operator = operator;
+
+ if (!separator)
+ separator = ' ';
+ arg_pair->separator = 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)
+{
+ return cmd->run_command(cmd);
+}
+EXPORT_SYMBOL_GPL(dynevent_create);
projects / linux.git / blobdiff