xlat.h

Go to the documentation of this file.

#pragma once
/*
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
/**
 * $Id: 6a418b6d4c9211a5b48d783f32366c33790a05d7 $
 *
 * @file lib/unlang/xlat.h
 * @brief xlat expansion parsing and evaluation API.
 *
 * @copyright 2015 The FreeRADIUS server project
 */
RCSIDH(xlat_h, "$Id: 6a418b6d4c9211a5b48d783f32366c33790a05d7 $")
 
#ifdef __cplusplus
extern "C" {
#endif
 
#include <freeradius-devel/util/retry.h>
 
/*
 *      Forward declarations
 */
typedef enum {
        XLAT_ACTION_PUSH_CHILD = 1,             //!< A deeper level of nesting needs to be evaluated.
        XLAT_ACTION_PUSH_UNLANG,                //!< An xlat function pushed an unlang frame onto the unlang stack.
                                                ///< This frame needs to be evaluated, and then we need to call
                                                ///< the xlat's resume function.
        XLAT_ACTION_YIELD,                      //!< An xlat function pushed a resume frame onto the stack.
        XLAT_ACTION_DONE,                       //!< We're done evaluating this level of nesting.
        XLAT_ACTION_FAIL                        //!< An xlat function failed.
} xlat_action_t;
 
typedef struct xlat_inst_s xlat_inst_t;
typedef struct xlat_thread_inst_s xlat_thread_inst_t;
 
#include <freeradius-devel/server/request.h>
 
typedef ssize_t (*xlat_escape_legacy_t)(request_t *request, char *out, size_t outlen, char const *in, void *arg);
 
#include <freeradius-devel/server/cf_util.h>
#include <freeradius-devel/server/signal.h>
#include <freeradius-devel/server/tmpl.h>
 
#include <freeradius-devel/util/heap.h>
#include <freeradius-devel/util/pair.h>
#include <freeradius-devel/util/sbuff.h>
#include <freeradius-devel/util/time.h>
#include <freeradius-devel/util/value.h>
 
#include <freeradius-devel/unlang/call_env.h>
#include <freeradius-devel/unlang/xlat_ctx.h>
 
/** Instance data for an xlat expansion node
 *
 */
struct xlat_inst_s {
        fr_heap_index_t         idx;            //!< Entry in heap of xlat instances.
                                                ///< Identical instances are used for
                                                ///< global instance data and thread-specific
                                                ///< instance data.
 
        xlat_exp_t              *node;          //!< Node this data relates to.
        void                    *data;          //!< xlat node specific instance data.
        call_env_t const        *call_env;      //!< Per call environment.
};
 
/** Thread specific instance data for xlat expansion node
 *
 */
struct xlat_thread_inst_s {
        fr_heap_index_t         idx;            //!< Entry in heap of xlat thread instances.
                                                ///< Identical instances are used for
                                                ///< global instance data and thread-specific
                                                ///< instance data.
 
        fr_event_list_t         *el;            //!< Event list associated with this thread.
 
        xlat_exp_t const        *node;          //!< Node this data relates to.
        void                    *data;          //!< Thread specific instance data.
 
        module_ctx_t const      *mctx;          //!< A synthesised module calling ctx containing
                                                ///< module global and thread instance data.
 
        uint64_t                total_calls;    //! total number of times we've been called
        uint64_t                active_callers; //! number of active callers.  i.e. number of current yields
};
 
typedef struct xlat_s xlat_t;
 
/** Flags that control resolution and evaluation
 *
 */
typedef struct {
        uint8_t                 needs_resolving : 1;    //!< Needs pass2 resolution.
        uint8_t                 pure : 1;               //!< has no external side effects, true for BOX, LITERAL, and some functions
        uint8_t                 impure_func : 1;        //!< xlat contains an impure function
        uint8_t                 can_purify : 1;         //!< if the xlat has a pure function with pure arguments.
 
        uint8_t                 constant : 1;           //!< xlat is just tmpl_attr_tail_data, or XLAT_BOX
        uint8_t                 xlat : 1;               //!< it's an xlat wrapper
} xlat_flags_t;
 
#define XLAT_FLAGS_INIT ((xlat_flags_t) { .pure = true, .can_purify = true, .constant = true, })
 
extern fr_table_num_sorted_t const xlat_action_table[];
extern size_t xlat_action_table_len;
 
/** A function used to escape an argument passed to an xlat
 *
 * @param[in] request           being processed.  Used mostly for debugging.
 * @param[in,out] vb            to escape
 * @param[in] uctx              a "context" for the escaping
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
typedef int (*xlat_escape_func_t)(request_t *request, fr_value_box_t *vb, void *uctx);
 
typedef enum {
        XLAT_ARG_VARIADIC_DISABLED      = 0,
        XLAT_ARG_VARIADIC_EMPTY_SQUASH  = 1,    //!< Empty argument groups are removed.
        XLAT_ARG_VARIADIC_EMPTY_KEEP    = 2,    //!< Empty argument groups are left alone,
                                                ///< and either passed through as empty groups
                                                ///< or null boxes.
} xlat_arg_parser_variadic_t;
 
/** Definition for a single argument consumend by an xlat function
 *
 */
typedef struct {
        bool                            required;       //!< Argument must be present, and non-empty.
        bool                            concat;         //!< Concat boxes together.
        bool                            single;         //!< Argument must only contain a single box
        bool                            will_escape;    //!< the function will do escaping and concatenation.
        xlat_arg_parser_variadic_t      variadic;       //!< All additional boxes should be processed
                                                        ///< using this definition.
        bool                            always_escape;  //!< Pass all arguments to escape function not just
                                                        ///< tainted ones.
        fr_type_t                       type;           //!< Type to cast argument to.
        xlat_escape_func_t              func;           //!< Function to handle tainted values.
        fr_value_box_safe_for_t         safe_for;       //!< Escaped value to set for boxes processed by
                                                        ///< this escape function.
        void                            *uctx;          //!< Argument to pass to escape callback.
} xlat_arg_parser_t;
 
typedef struct {
        tmpl_res_rules_t const  *tr_rules;      //!< tmpl resolution rules.
        bool                    allow_unresolved; //!< If false, all resolution steps must be completed
                                                ///< this round, otherwise an error will be produced.
} xlat_res_rules_t;
 
#define XLAT_ARG_PARSER_TERMINATOR { .required = false, .concat = false, .single = false, .variadic = false, \
                                        .type = FR_TYPE_NULL, .func = NULL, .uctx = NULL }
 
/** A callback when the the timeout occurs
 *
 * Used when a xlat needs wait for an event.
 * Typically the callback is set, and then the xlat returns unlang_xlat_yield().
 *
 * @note The callback is automatically removed on unlang_interpret_mark_runnable(), i.e. if an event
 *      on a registered FD occurs before the timeout event fires.
 *
 * @param[in] xctx              xlat calling ctx.  Contains all instance data.
 * @param[in] request           the request.
 * @param[in] fired             the time the timeout event actually fired.
 */
typedef void (*fr_unlang_xlat_timeout_t)(xlat_ctx_t const *xctx, request_t *request, fr_time_t fired);
 
/** A callback when the the timeout occurs
 *
 * Used when a xlat needs wait for an event.
 * Typically the callback is set, and then the xlat returns unlang_xlat_yield().
 *
 * @note The callback is automatically removed on unlang_interpret_mark_runnable(), i.e. if an event
 *      on a registered FD occurs before the timeout event fires.
 *
 * @param[in] xctx              xlat calling ctx.  Contains all instance data.
 * @param[in] request           the request.
 * @param[in] retry             retry status.  "now" is in retry->updated
 */
typedef void (*fr_unlang_xlat_retry_t)(xlat_ctx_t const *xctx, request_t *request, fr_retry_t const *retry);
 
/** A callback when the FD is ready for reading
 *
 * Used when a xlat needs to read from an FD.  Typically the callback is set, and then the
 * xlat returns unlang_xlat_yield().
 *
 * @note The callback is automatically removed on unlang_interpret_mark_runnable(), so
 *
 * @param[in] xctx              xlat calling ctx.  Contains all instance data.
 * @param[in] request           the current request.
 * @param[in] fd                the file descriptor.
 */
typedef void (*fr_unlang_xlat_fd_event_t)(xlat_ctx_t const *xctx, request_t *request, int fd);
 
/** xlat callback function
 *
 * Ingests a list of value boxes as arguments.
 *
 * @param[in] ctx               to allocate any fr_value_box_t in.
 * @param[out] out              Where to append #fr_value_box_t containing the output of
 *                              this function.
 * @param[in] xctx              xlat calling ctx.  Contains all instance data and the resume
 *                              ctx if this function is being resumed.
 * @param[in] request           The current request.
 * @param[in] in                Input arguments.
 * @return
 *      - XLAT_ACTION_YIELD     xlat function is waiting on an I/O event and
 *                              has pushed a resumption function onto the stack.
 *      - XLAT_ACTION_DONE      xlat function completed. This does not necessarily
 *                              mean it turned a result.
 *      - XLAT_ACTION_FAIL      the xlat function failed.
 */
typedef xlat_action_t (*xlat_func_t)(TALLOC_CTX *ctx, fr_dcursor_t *out,
                                     xlat_ctx_t const *xctx, request_t *request, fr_value_box_list_t *in);
 
/** A callback when the request gets a fr_signal_t.
 *
 * @note The callback is automatically removed on unlang_interpret_mark_runnable().
 *
 * @param[in] request           The current request.
 * @param[in] xctx              xlat calling ctx.  Contains all instance data.
 * @param[in] action            which is signalling the request.
 */
typedef void (*xlat_func_signal_t)(xlat_ctx_t const *xctx, request_t *request, fr_signal_t action);
 
/** Allocate new instance data for an xlat instance
 *
 * @param[in] xctx      instantiate/detach calling ctx.
 
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
typedef int (*xlat_instantiate_t)(xlat_inst_ctx_t const *xctx);
 
/** Allocate new thread instance data for an xlat instance
 *
 * @param[in] xctx      thread instantiate/detach ctx.
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
typedef int (*xlat_thread_instantiate_t)(xlat_thread_inst_ctx_t const *xctx);
 
/** xlat detach callback
 *
 * Is called whenever an xlat_node_t is freed.
 *
 * Detach should close all handles associated with the xlat instance, and
 * free any memory allocated during instantiate.
 *
 * @param[in] xctx      instantiate/detach calling ctx.
 * @return
 *      - 0 on success.
 *      - -1 if detach failed.
 */
typedef int (*xlat_detach_t)(xlat_inst_ctx_t const *xctx);
 
/** xlat thread detach callback
 *
 * Is called whenever an xlat_node_t is freed (if ephemeral),
 * or when a thread exits.
 *
 * Detach should close all handles associated with the xlat instance, and
 * free any memory allocated during instantiate.
 *
 * @param[in] xctx      thread instantiate/detach calling ctx.
 * @return
 *      - 0 on success.
 *      - -1 if detach failed.
 */
typedef int (*xlat_thread_detach_t)(xlat_thread_inst_ctx_t const *xctx);
 
/** Set the next argument to the next item in the input list or NULL
 *
 * @param[in] _list     we're extracting arguments from.
 * @param[in] _prev     argument.
 * @param[in] _curr     argument we're populating.
 */
#define XLAT_ARGS_NEXT(_list, _prev, _curr) *(_curr) = likely(*(_prev) != NULL) ? fr_value_box_list_next(_list, *(_prev)) : NULL
 
#define XLAT_ARGS_1(_list, _a) \
        *(_a) = fr_value_box_list_head(_list)
 
#define XLAT_ARGS_2(_list, _a, _b) \
        do { \
                *(_a) = fr_value_box_list_head(_list); \
                XLAT_ARGS_NEXT(_list, _a, _b); \
        } while (0)
 
#define XLAT_ARGS_3(_list, _a, _b, _c) \
        do { \
                *(_a) = fr_value_box_list_head(_list); \
                XLAT_ARGS_NEXT(_list, _a, _b); \
                XLAT_ARGS_NEXT(_list, _b, _c); \
        } while (0)
 
#define XLAT_ARGS_4(_list, _a, _b, _c, _d) \
        do { \
                *(_a) = fr_value_box_list_head(_list); \
                XLAT_ARGS_NEXT(_list, _a, _b); \
                XLAT_ARGS_NEXT(_list, _b, _c); \
                XLAT_ARGS_NEXT(_list, _c, _d); \
        } while (0)
 
#define XLAT_ARGS_5(_list, _a, _b, _c, _d, _e) \
        do { \
                *(_a) = fr_value_box_list_head(_list); \
                XLAT_ARGS_NEXT(_list, _a, _b); \
                XLAT_ARGS_NEXT(_list, _b, _c); \
                XLAT_ARGS_NEXT(_list, _c, _d); \
                XLAT_ARGS_NEXT(_list, _d, _e); \
        } while (0)
 
#define XLAT_ARGS_6(_list, _a, _b, _c, _d, _e, _f) \
        do { \
                *(_a) = fr_value_box_list_head(_list); \
                XLAT_ARGS_NEXT(_list, _a, _b); \
                XLAT_ARGS_NEXT(_list, _b, _c); \
                XLAT_ARGS_NEXT(_list, _c, _d); \
                XLAT_ARGS_NEXT(_list, _d, _e); \
                XLAT_ARGS_NEXT(_list, _e, _f); \
        } while (0)
 
#define XLAT_ARGS_7(_list, _a, _b, _c, _d, _e, _f, _g) \
        do { \
                *(_a) = fr_value_box_list_head(_list); \
                XLAT_ARGS_NEXT(_list, _a, _b); \
                XLAT_ARGS_NEXT(_list, _b, _c); \
                XLAT_ARGS_NEXT(_list, _c, _d); \
                XLAT_ARGS_NEXT(_list, _d, _e); \
                XLAT_ARGS_NEXT(_list, _e, _f); \
                XLAT_ARGS_NEXT(_list, _f, _g); \
        } while (0)
 
#define XLAT_ARGS_8(_list, _a, _b, _c, _d, _e, _f, _g, _h) \
        do { \
                *(_a) = fr_value_box_list_head(_list); \
                XLAT_ARGS_NEXT(_list, _a, _b); \
                XLAT_ARGS_NEXT(_list, _b, _c); \
                XLAT_ARGS_NEXT(_list, _c, _d); \
                XLAT_ARGS_NEXT(_list, _d, _e); \
                XLAT_ARGS_NEXT(_list, _e, _f); \
                XLAT_ARGS_NEXT(_list, _f, _g); \
                XLAT_ARGS_NEXT(_list, _g, _h); \
        } while (0)
 
/** Trampoline macro for selecting which ``XLAT_ARGS_<num>`` macro to expand
 *
 *
 * @param[in] XLAT_ARGS_N       the name of the macro to expand.
 *                              Created by concatenating ``XLAT_ARGS_ + <number of variadic arguments>``.
 * @param[in] _list             The input list of value boxes.
 * @param[in] ...               The variadic arguments themselves.
 */
#define _XLAT_ARGS_X(XLAT_ARGS_N, _list, ...) XLAT_ARGS_N(_list, __VA_ARGS__)
 
/** Populate local variables with value boxes from the input list
 *
 * @param[in] _list             input list to pull arguments from.
 * @param[in] ...               1-8 output boxes pointers `fr_value_box_t **`
 *                              e.g. `XLAT_ARGS(in, &arg0, &arg1, &argN)``.
 */
#define XLAT_ARGS(_list, ...) _XLAT_ARGS_X(JOIN(XLAT_ARGS_, VA_NARG(__VA_ARGS__)), _list, __VA_ARGS__)
 
ssize_t         xlat_eval(char *out, size_t outlen, request_t *request, char const *fmt, xlat_escape_legacy_t escape,
                          void const *escape_ctx)
                          CC_HINT(nonnull (1 ,3 ,4));
 
ssize_t         xlat_eval_compiled(char *out, size_t outlen, request_t *request, xlat_exp_head_t const *head,
                                   xlat_escape_legacy_t escape, void const *escape_ctx)
                                   CC_HINT(nonnull (1 ,3 ,4));
 
ssize_t         xlat_aeval(TALLOC_CTX *ctx, char **out, request_t *request,
                           char const *fmt, xlat_escape_legacy_t escape, void const *escape_ctx)
                           CC_HINT(nonnull(2, 3, 4));
 
ssize_t         xlat_aeval_compiled(TALLOC_CTX *ctx, char **out, request_t *request,
                                    xlat_exp_head_t const *head, xlat_escape_legacy_t escape, void const *escape_ctx)
                                    CC_HINT(nonnull (2, 3, 4));
 
int             xlat_flatten_to_argv(TALLOC_CTX *ctx, xlat_exp_head_t ***argv, xlat_exp_head_t *head);
 
fr_slen_t       xlat_tokenize_expression(TALLOC_CTX *ctx, xlat_exp_head_t **head, fr_sbuff_t *in,
                                         fr_sbuff_parse_rules_t const *p_rules, tmpl_rules_t const *t_rules) CC_HINT(nonnull(1,2,3));
 
fr_slen_t       xlat_tokenize_condition(TALLOC_CTX *ctx, xlat_exp_head_t **head, fr_sbuff_t *in,
                                        fr_sbuff_parse_rules_t const *p_rules, tmpl_rules_t const *t_rules) CC_HINT(nonnull(1,2,3));
 
fr_slen_t       xlat_tokenize_argv(TALLOC_CTX *ctx, xlat_exp_head_t **head, fr_sbuff_t *in,
                                   xlat_t const *xlat, fr_sbuff_parse_rules_t const *p_rules, tmpl_rules_t const *t_rules,
                                   bool spaces) CC_HINT(nonnull(1,2,3,6));
 
fr_slen_t       xlat_tokenize(TALLOC_CTX *ctx, xlat_exp_head_t **head, fr_sbuff_t *in,
                              fr_sbuff_parse_rules_t const *p_rules, tmpl_rules_t const *t_rules);
 
fr_slen_t       xlat_print(fr_sbuff_t *in, xlat_exp_head_t const *node, fr_sbuff_escape_rules_t const *e_rules);
 
static inline fr_slen_t xlat_aprint(TALLOC_CTX *ctx, char **out, xlat_exp_head_t const *head,
                                    fr_sbuff_escape_rules_t const *e_rules)
                SBUFF_OUT_TALLOC_FUNC_NO_LEN_DEF(xlat_print, head, e_rules)
 
bool            xlat_is_truthy(xlat_exp_head_t const *head, bool *out);
 
int             xlat_validate_function_args(xlat_exp_t *node);
 
void            xlat_debug(xlat_exp_t const *node);
 
void            xlat_debug_head(xlat_exp_head_t const *head);
 
bool            xlat_is_literal(xlat_exp_head_t const *head);
 
bool            xlat_needs_resolving(xlat_exp_head_t const *head);
 
bool            xlat_to_string(TALLOC_CTX *ctx, char **str, xlat_exp_head_t **head);
 
int             xlat_resolve(xlat_exp_head_t *head, xlat_res_rules_t const *xr_rules);
 
void            xlat_debug_attr_list(request_t *request, fr_pair_list_t const *list);
void            xlat_debug_attr_vp(request_t *request, fr_pair_t *vp, tmpl_t const *vpt);
 
xlat_action_t   xlat_transparent(UNUSED TALLOC_CTX *ctx, fr_dcursor_t *out,
                                 UNUSED xlat_ctx_t const *xctx,
                                 request_t *request, fr_value_box_list_t *args);
 
/*
 *      xlat_tokenize.c
 */
tmpl_t          *xlat_to_tmpl_attr(TALLOC_CTX *ctx, xlat_exp_head_t *xlat);
 
bool            xlat_impure_func(xlat_exp_head_t const *head) CC_HINT(nonnull);
 
fr_type_t       xlat_data_type(xlat_exp_head_t const *head);
 
/*
 *      xlat_alloc.c
 */
int             _xlat_copy(NDEBUG_LOCATION_ARGS TALLOC_CTX *ctx, xlat_exp_head_t *out, xlat_exp_head_t const *in);
#define         xlat_copy(_ctx, _out, _in) _xlat_copy(NDEBUG_LOCATION_EXP _ctx, _out, _in)
#ifdef WITH_VERIFY_PTR
void            xlat_exp_verify(xlat_exp_t const *node);
void            xlat_exp_head_verify(xlat_exp_head_t const *head);
 
#  define XLAT_VERIFY(_node) xlat_exp_verify(_node)
#  define XLAT_HEAD_VERIFY(_head) xlat_exp_head_verify(_head)
#else
#  define XLAT_VERIFY(_node)
#  define XLAT_HEAD_VERIFY(_head)
#endif
 
/*
 *      xlat_inst.c
 */
xlat_thread_inst_t *xlat_thread_instance_find(xlat_exp_t const *node);
 
int             xlat_thread_instantiate(TALLOC_CTX *ctx, fr_event_list_t *el);
 
int             xlat_instantiate(void);
 
void            xlat_thread_detach(void);
 
int             xlat_instance_unregister_func(xlat_exp_t *node);
 
int             xlat_instance_register_func(xlat_exp_t *node);
 
int             xlat_finalize(xlat_exp_head_t *head, fr_event_list_t *runtime_el); /* xlat_instance_register() or xlat_instantiate_ephemeral() */
 
void            xlat_instances_free(void);
 
/*
 *      xlat_purify.c
 */
typedef struct unlang_interpret_s unlang_interpret_t;
int             xlat_purify(xlat_exp_head_t *head, unlang_interpret_t *intp);
 
int             xlat_purify_op(TALLOC_CTX *ctx, xlat_exp_t **out, xlat_exp_t *lhs, fr_token_t op, xlat_exp_t *rhs);
 
/*
 *      xlat.c
 */
int             unlang_xlat_timeout_add(request_t *request, fr_unlang_xlat_timeout_t callback,
                                        void const *rctx, fr_time_t when);
 
int             unlang_xlat_push(TALLOC_CTX *ctx, bool *p_success, fr_value_box_list_t *out,
                                 request_t *request, xlat_exp_head_t const *head, bool top_frame)
                                 CC_HINT(warn_unused_result);
 
int             unlang_xlat_eval(TALLOC_CTX *ctx, fr_value_box_list_t *out,
                                 request_t *request, xlat_exp_head_t const *head)
                                 CC_HINT(warn_unused_result);
 
int             unlang_xlat_eval_type(TALLOC_CTX *ctx, fr_value_box_t *out, fr_type_t type, fr_dict_attr_t const *enumv,
                                      request_t *request, xlat_exp_head_t const *head)
                                      CC_HINT(warn_unused_result);
 
xlat_action_t   unlang_xlat_yield(request_t *request,
                                  xlat_func_t callback, xlat_func_signal_t signal, fr_signal_t sigmask,
                                  void *rctx);
 
xlat_action_t   unlang_xlat_yield_to_retry(request_t *request, xlat_func_t resume, fr_unlang_xlat_retry_t retry,
                                           xlat_func_signal_t signal, fr_signal_t sigmask, void *rctx,
                                           fr_retry_config_t const *retry_cfg);
 
/*
 *      xlat_builtin.c
 */
int             xlat_protocols_register(void);
int             xlat_global_init(void);
void            xlat_global_free(void);
 
#ifdef __cplusplus
}
#endif