search.h 4.5 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. #ifndef CONFIG_SPL_BUILD
  27. int (*callback)(const char *name, const char *value, enum env_op op,
  28. int flags);
  29. #endif
  30. int flags;
  31. };
  32. /*
  33. * Family of hash table handling functions. The functions also
  34. * have reentrant counterparts ending with _r. The non-reentrant
  35. * functions all work on a single internal hash table.
  36. */
  37. /* Data type for reentrant functions. */
  38. struct hsearch_data {
  39. struct env_entry_node *table;
  40. unsigned int size;
  41. unsigned int filled;
  42. /*
  43. * Callback function which will check whether the given change for variable
  44. * "item" to "newval" may be applied or not, and possibly apply such change.
  45. * When (flag & H_FORCE) is set, it shall not print out any error message and
  46. * shall force overwriting of write-once variables.
  47. * Must return 0 for approval, 1 for denial.
  48. */
  49. int (*change_ok)(const struct env_entry *item, const char *newval,
  50. enum env_op, int flag);
  51. };
  52. /* Create a new hash table which will contain at most "nel" elements. */
  53. int hcreate_r(size_t nel, struct hsearch_data *htab);
  54. /* Destroy current internal hash table. */
  55. void hdestroy_r(struct hsearch_data *htab);
  56. /*
  57. * Search for entry matching item.key in internal hash table. If
  58. * action is `ENV_FIND' return found entry or signal error by returning
  59. * NULL. If action is `ENV_ENTER' replace existing data (if any) with
  60. * item.data.
  61. * */
  62. int hsearch_r(struct env_entry item, enum env_action action,
  63. struct env_entry **retval, struct hsearch_data *htab, int flag);
  64. /*
  65. * Search for an entry matching "match". Otherwise, Same semantics
  66. * as hsearch_r().
  67. */
  68. int hmatch_r(const char *match, int last_idx, struct env_entry **retval,
  69. struct hsearch_data *htab);
  70. /**
  71. * hdelete_r() - Search and delete entry in internal hash table
  72. *
  73. * @key: Name of entry to delete
  74. * @htab: Hash table
  75. * @flag: Flags to use (H_...)
  76. * Return: 0 on success, -ENOENT if not found, -EPERM if the hash table callback
  77. * rejected changing the variable, -EINVAL if the hash table refused to
  78. * delete the variable
  79. */
  80. int hdelete_r(const char *key, struct hsearch_data *htab, int flag);
  81. ssize_t hexport_r(struct hsearch_data *htab, const char sep, int flag,
  82. char **resp, size_t size, int argc, char *const argv[]);
  83. /*
  84. * nvars: length of vars array
  85. * vars: array of strings (variable names) to import (nvars == 0 means all)
  86. */
  87. int himport_r(struct hsearch_data *htab, const char *env, size_t size,
  88. const char sep, int flag, int crlf_is_lf, int nvars,
  89. char * const vars[]);
  90. /* Walk the whole table calling the callback on each element */
  91. int hwalk_r(struct hsearch_data *htab,
  92. int (*callback)(struct env_entry *entry));
  93. /* Flags for himport_r(), hexport_r(), hdelete_r(), and hsearch_r() */
  94. #define H_NOCLEAR (1 << 0) /* do not clear hash table before importing */
  95. #define H_FORCE (1 << 1) /* overwrite read-only/write-once variables */
  96. #define H_INTERACTIVE (1 << 2) /* indicate that an import is user directed */
  97. #define H_HIDE_DOT (1 << 3) /* don't print env vars that begin with '.' */
  98. #define H_MATCH_KEY (1 << 4) /* search/grep key = variable names */
  99. #define H_MATCH_DATA (1 << 5) /* search/grep data = variable values */
  100. #define H_MATCH_BOTH (H_MATCH_KEY | H_MATCH_DATA) /* search/grep both */
  101. #define H_MATCH_IDENT (1 << 6) /* search for indentical strings */
  102. #define H_MATCH_SUBSTR (1 << 7) /* search for substring matches */
  103. #define H_MATCH_REGEX (1 << 8) /* search for regular expression matches */
  104. #define H_MATCH_METHOD (H_MATCH_IDENT | H_MATCH_SUBSTR | H_MATCH_REGEX)
  105. #define H_PROGRAMMATIC (1 << 9) /* indicate that an import is from env_set() */
  106. #define H_ORIGIN_FLAGS (H_INTERACTIVE | H_PROGRAMMATIC)
  107. #define H_DEFAULT (1 << 10) /* indicate that an import is default env */
  108. #define H_EXTERNAL (1 << 11) /* indicate that an import is external env */
  109. #endif /* _SEARCH_H_ */