1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __LINUX_TEXTSEARCH_H 3 #define __LINUX_TEXTSEARCH_H 4 5 #include <linux/types.h> 6 #include <linux/list.h> 7 #include <linux/kernel.h> 8 #include <linux/err.h> 9 #include <linux/slab.h> 10 11 struct module; 12 13 struct ts_config; 14 15 #define TS_AUTOLOAD 1 /* Automatically load textsearch modules when needed */ 16 #define TS_IGNORECASE 2 /* Searches string case insensitively */ 17 18 /** 19 * struct ts_state - search state 20 * @offset: offset for next match 21 * @cb: control buffer, for persistent variables of get_next_block() 22 */ 23 struct ts_state 24 { 25 unsigned int offset; 26 char cb[48]; 27 }; 28 29 /** 30 * struct ts_ops - search module operations 31 * @name: name of search algorithm 32 * @init: initialization function to prepare a search 33 * @find: find the next occurrence of the pattern 34 * @destroy: destroy algorithm specific parts of a search configuration 35 * @get_pattern: return head of pattern 36 * @get_pattern_len: return length of pattern 37 * @owner: module reference to algorithm 38 * @list: list to search 39 */ 40 struct ts_ops 41 { 42 const char *name; 43 struct ts_config * (*init)(const void *, unsigned int, gfp_t, int); 44 unsigned int (*find)(struct ts_config *, 45 struct ts_state *); 46 void (*destroy)(struct ts_config *); 47 void * (*get_pattern)(struct ts_config *); 48 unsigned int (*get_pattern_len)(struct ts_config *); 49 struct module *owner; 50 struct list_head list; 51 }; 52 53 /** 54 * struct ts_config - search configuration 55 * @ops: operations of chosen algorithm 56 * @flags: flags 57 * @get_next_block: callback to fetch the next block to search in 58 * @finish: callback to finalize a search 59 */ 60 struct ts_config 61 { 62 struct ts_ops *ops; 63 int flags; 64 65 /** 66 * @get_next_block: fetch next block of data 67 * @consumed: number of bytes consumed by the caller 68 * @dst: destination buffer 69 * @conf: search configuration 70 * @state: search state 71 * 72 * Called repeatedly until 0 is returned. Must assign the 73 * head of the next block of data to &*dst and return the length 74 * of the block or 0 if at the end. consumed == 0 indicates 75 * a new search. May store/read persistent values in state->cb. 76 */ 77 unsigned int (*get_next_block)(unsigned int consumed, 78 const u8 **dst, 79 struct ts_config *conf, 80 struct ts_state *state); 81 82 /** 83 * @finish: finalize/clean a series of get_next_block() calls 84 * @conf: search configuration 85 * @state: search state 86 * 87 * Called after the last use of get_next_block(), may be used 88 * to cleanup any leftovers. 89 */ 90 void (*finish)(struct ts_config *conf, 91 struct ts_state *state); 92 }; 93 94 /** 95 * textsearch_next - continue searching for a pattern 96 * @conf: search configuration 97 * @state: search state 98 * 99 * Continues a search looking for more occurrences of the pattern. 100 * textsearch_find() must be called to find the first occurrence 101 * in order to reset the state. 102 * 103 * Returns the position of the next occurrence of the pattern or 104 * UINT_MAX if not match was found. 105 */ 106 static inline unsigned int textsearch_next(struct ts_config *conf, 107 struct ts_state *state) 108 { 109 unsigned int ret = conf->ops->find(conf, state); 110 111 if (conf->finish) 112 conf->finish(conf, state); 113 114 return ret; 115 } 116 117 /** 118 * textsearch_find - start searching for a pattern 119 * @conf: search configuration 120 * @state: search state 121 * 122 * Returns the position of first occurrence of the pattern or 123 * UINT_MAX if no match was found. 124 */ 125 static inline unsigned int textsearch_find(struct ts_config *conf, 126 struct ts_state *state) 127 { 128 state->offset = 0; 129 return textsearch_next(conf, state); 130 } 131 132 /** 133 * textsearch_get_pattern - return head of the pattern 134 * @conf: search configuration 135 */ 136 static inline void *textsearch_get_pattern(struct ts_config *conf) 137 { 138 return conf->ops->get_pattern(conf); 139 } 140 141 /** 142 * textsearch_get_pattern_len - return length of the pattern 143 * @conf: search configuration 144 */ 145 static inline unsigned int textsearch_get_pattern_len(struct ts_config *conf) 146 { 147 return conf->ops->get_pattern_len(conf); 148 } 149 150 extern int textsearch_register(struct ts_ops *); 151 extern int textsearch_unregister(struct ts_ops *); 152 extern struct ts_config *textsearch_prepare(const char *, const void *, 153 unsigned int, gfp_t, int); 154 extern void textsearch_destroy(struct ts_config *conf); 155 extern unsigned int textsearch_find_continuous(struct ts_config *, 156 struct ts_state *, 157 const void *, unsigned int); 158 159 160 #define TS_PRIV_ALIGNTO 8 161 #define TS_PRIV_ALIGN(len) (((len) + TS_PRIV_ALIGNTO-1) & ~(TS_PRIV_ALIGNTO-1)) 162 163 static inline struct ts_config *alloc_ts_config(size_t payload, 164 gfp_t gfp_mask) 165 { 166 struct ts_config *conf; 167 168 conf = kzalloc(TS_PRIV_ALIGN(sizeof(*conf)) + payload, gfp_mask); 169 if (conf == NULL) 170 return ERR_PTR(-ENOMEM); 171 172 return conf; 173 } 174 175 static inline void *ts_config_priv(struct ts_config *conf) 176 { 177 return ((u8 *) conf + TS_PRIV_ALIGN(sizeof(struct ts_config))); 178 } 179 180 #endif 181