180 lines
4.7 KiB
C
180 lines
4.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_TEXTSEARCH_H
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#define __LINUX_TEXTSEARCH_H
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#include <linux/types.h>
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#include <linux/list.h>
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#include <linux/kernel.h>
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#include <linux/err.h>
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#include <linux/slab.h>
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struct module;
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struct ts_config;
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#define TS_AUTOLOAD 1 /* Automatically load textsearch modules when needed */
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#define TS_IGNORECASE 2 /* Searches string case insensitively */
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/**
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* struct ts_state - search state
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* @offset: offset for next match
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* @cb: control buffer, for persistent variables of get_next_block()
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*/
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struct ts_state
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{
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unsigned int offset;
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char cb[40];
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};
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/**
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* struct ts_ops - search module operations
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* @name: name of search algorithm
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* @init: initialization function to prepare a search
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* @find: find the next occurrence of the pattern
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* @destroy: destroy algorithm specific parts of a search configuration
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* @get_pattern: return head of pattern
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* @get_pattern_len: return length of pattern
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* @owner: module reference to algorithm
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*/
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struct ts_ops
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{
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const char *name;
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struct ts_config * (*init)(const void *, unsigned int, gfp_t, int);
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unsigned int (*find)(struct ts_config *,
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struct ts_state *);
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void (*destroy)(struct ts_config *);
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void * (*get_pattern)(struct ts_config *);
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unsigned int (*get_pattern_len)(struct ts_config *);
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struct module *owner;
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struct list_head list;
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};
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/**
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* struct ts_config - search configuration
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* @ops: operations of chosen algorithm
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* @flags: flags
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* @get_next_block: callback to fetch the next block to search in
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* @finish: callback to finalize a search
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*/
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struct ts_config
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{
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struct ts_ops *ops;
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int flags;
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/**
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* @get_next_block: fetch next block of data
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* @consumed: number of bytes consumed by the caller
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* @dst: destination buffer
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* @conf: search configuration
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* @state: search state
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*
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* Called repeatedly until 0 is returned. Must assign the
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* head of the next block of data to &*dst and return the length
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* of the block or 0 if at the end. consumed == 0 indicates
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* a new search. May store/read persistent values in state->cb.
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*/
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unsigned int (*get_next_block)(unsigned int consumed,
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const u8 **dst,
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struct ts_config *conf,
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struct ts_state *state);
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/**
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* @finish: finalize/clean a series of get_next_block() calls
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* @conf: search configuration
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* @state: search state
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*
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* Called after the last use of get_next_block(), may be used
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* to cleanup any leftovers.
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*/
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void (*finish)(struct ts_config *conf,
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struct ts_state *state);
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};
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/**
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* textsearch_next - continue searching for a pattern
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* @conf: search configuration
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* @state: search state
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*
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* Continues a search looking for more occurrences of the pattern.
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* textsearch_find() must be called to find the first occurrence
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* in order to reset the state.
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*
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* Returns the position of the next occurrence of the pattern or
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* UINT_MAX if not match was found.
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*/
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static inline unsigned int textsearch_next(struct ts_config *conf,
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struct ts_state *state)
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{
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unsigned int ret = conf->ops->find(conf, state);
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if (conf->finish)
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conf->finish(conf, state);
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return ret;
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}
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/**
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* textsearch_find - start searching for a pattern
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* @conf: search configuration
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* @state: search state
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*
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* Returns the position of first occurrence of the pattern or
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* UINT_MAX if no match was found.
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*/
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static inline unsigned int textsearch_find(struct ts_config *conf,
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struct ts_state *state)
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{
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state->offset = 0;
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return textsearch_next(conf, state);
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}
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/**
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* textsearch_get_pattern - return head of the pattern
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* @conf: search configuration
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*/
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static inline void *textsearch_get_pattern(struct ts_config *conf)
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{
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return conf->ops->get_pattern(conf);
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}
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/**
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* textsearch_get_pattern_len - return length of the pattern
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* @conf: search configuration
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*/
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static inline unsigned int textsearch_get_pattern_len(struct ts_config *conf)
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{
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return conf->ops->get_pattern_len(conf);
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}
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extern int textsearch_register(struct ts_ops *);
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extern int textsearch_unregister(struct ts_ops *);
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extern struct ts_config *textsearch_prepare(const char *, const void *,
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unsigned int, gfp_t, int);
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extern void textsearch_destroy(struct ts_config *conf);
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extern unsigned int textsearch_find_continuous(struct ts_config *,
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struct ts_state *,
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const void *, unsigned int);
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#define TS_PRIV_ALIGNTO 8
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#define TS_PRIV_ALIGN(len) (((len) + TS_PRIV_ALIGNTO-1) & ~(TS_PRIV_ALIGNTO-1))
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static inline struct ts_config *alloc_ts_config(size_t payload,
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gfp_t gfp_mask)
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{
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struct ts_config *conf;
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conf = kzalloc(TS_PRIV_ALIGN(sizeof(*conf)) + payload, gfp_mask);
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if (conf == NULL)
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return ERR_PTR(-ENOMEM);
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return conf;
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}
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static inline void *ts_config_priv(struct ts_config *conf)
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{
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return ((u8 *) conf + TS_PRIV_ALIGN(sizeof(struct ts_config)));
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}
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#endif
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