search.h 4.0 KB

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  1. /* SPDX-License-Identifier: LGPL-2.1+ */
  2. /*
  3. * Declarations for System V style searching functions.
  4. * Copyright (C) 1995-1999, 2000 Free Software Foundation, Inc.
  5. * This file is part of the GNU C Library.
  6. */
  7. /*
  8. * Based on code from uClibc-0.9.30.3
  9. * Extensions for use within U-Boot
  10. * Copyright (C) 2010-2013 Wolfgang Denk <wd@denx.de>
  11. */
  12. #ifndef _SEARCH_H_
  13. #define _SEARCH_H_
  14. #include <env.h>
  15. #include <stddef.h>
  16. #define set_errno(val) do { errno = val; } while (0)
  17. /* enum env_action: action which shall be performed in the call to hsearch */
  18. enum env_action {
  19. ENV_FIND,
  20. ENV_ENTER,
  21. };
  22. /** struct env_entry - An entry in the environment hashtable */
  23. struct env_entry {
  24. const char *key;
  25. char *data;
  26. int (*callback)(const char *name, const char *value, enum env_op op,
  27. int flags);
  28. int flags;
  29. };
  30. /*
  31. * Family of hash table handling functions. The functions also
  32. * have reentrant counterparts ending with _r. The non-reentrant
  33. * functions all work on a single internal hash table.
  34. */
  35. /* Data type for reentrant functions. */
  36. struct hsearch_data {
  37. struct env_entry_node *table;
  38. unsigned int size;
  39. unsigned int filled;
  40. /*
  41. * Callback function which will check whether the given change for variable
  42. * "item" to "newval" may be applied or not, and possibly apply such change.
  43. * When (flag & H_FORCE) is set, it shall not print out any error message and
  44. * shall force overwriting of write-once variables.
  45. * Must return 0 for approval, 1 for denial.
  46. */
  47. int (*change_ok)(const struct env_entry *item, const char *newval,
  48. enum env_op, int flag);
  49. };
  50. /* Create a new hash table which will contain at most "nel" elements. */
  51. int hcreate_r(size_t nel, struct hsearch_data *htab);
  52. /* Destroy current internal hash table. */
  53. void hdestroy_r(struct hsearch_data *htab);
  54. /*
  55. * Search for entry matching item.key in internal hash table. If
  56. * action is `ENV_FIND' return found entry or signal error by returning
  57. * NULL. If action is `ENV_ENTER' replace existing data (if any) with
  58. * item.data.
  59. * */
  60. int hsearch_r(struct env_entry item, enum env_action action,
  61. struct env_entry **retval, struct hsearch_data *htab, int flag);
  62. /*
  63. * Search for an entry matching "match". Otherwise, Same semantics
  64. * as hsearch_r().
  65. */
  66. int hmatch_r(const char *match, int last_idx, struct env_entry **retval,
  67. struct hsearch_data *htab);
  68. /* Search and delete entry matching "key" in internal hash table. */
  69. int hdelete_r(const char *key, struct hsearch_data *htab, int flag);
  70. ssize_t hexport_r(struct hsearch_data *htab, const char sep, int flag,
  71. char **resp, size_t size, int argc, char * const argv[]);
  72. /*
  73. * nvars: length of vars array
  74. * vars: array of strings (variable names) to import (nvars == 0 means all)
  75. */
  76. int himport_r(struct hsearch_data *htab, const char *env, size_t size,
  77. const char sep, int flag, int crlf_is_lf, int nvars,
  78. char * const vars[]);
  79. /* Walk the whole table calling the callback on each element */
  80. int hwalk_r(struct hsearch_data *htab,
  81. int (*callback)(struct env_entry *entry));
  82. /* Flags for himport_r(), hexport_r(), hdelete_r(), and hsearch_r() */
  83. #define H_NOCLEAR (1 << 0) /* do not clear hash table before importing */
  84. #define H_FORCE (1 << 1) /* overwrite read-only/write-once variables */
  85. #define H_INTERACTIVE (1 << 2) /* indicate that an import is user directed */
  86. #define H_HIDE_DOT (1 << 3) /* don't print env vars that begin with '.' */
  87. #define H_MATCH_KEY (1 << 4) /* search/grep key = variable names */
  88. #define H_MATCH_DATA (1 << 5) /* search/grep data = variable values */
  89. #define H_MATCH_BOTH (H_MATCH_KEY | H_MATCH_DATA) /* search/grep both */
  90. #define H_MATCH_IDENT (1 << 6) /* search for indentical strings */
  91. #define H_MATCH_SUBSTR (1 << 7) /* search for substring matches */
  92. #define H_MATCH_REGEX (1 << 8) /* search for regular expression matches */
  93. #define H_MATCH_METHOD (H_MATCH_IDENT | H_MATCH_SUBSTR | H_MATCH_REGEX)
  94. #define H_PROGRAMMATIC (1 << 9) /* indicate that an import is from env_set() */
  95. #define H_ORIGIN_FLAGS (H_INTERACTIVE | H_PROGRAMMATIC)
  96. #endif /* _SEARCH_H_ */