include/linux/textsearch.h

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