OBJ_nid2obj.pod 4.7 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151
  1. =pod
  2. =head1 NAME
  3. OBJ_nid2obj, OBJ_nid2ln, OBJ_nid2sn, OBJ_obj2nid, OBJ_txt2nid, OBJ_ln2nid, OBJ_sn2nid,
  4. OBJ_cmp, OBJ_dup, OBJ_txt2obj, OBJ_obj2txt, OBJ_create, OBJ_cleanup - ASN1 object utility
  5. functions
  6. =head1 SYNOPSIS
  7. #include <openssl/objects.h>
  8. ASN1_OBJECT * OBJ_nid2obj(int n);
  9. const char * OBJ_nid2ln(int n);
  10. const char * OBJ_nid2sn(int n);
  11. int OBJ_obj2nid(const ASN1_OBJECT *o);
  12. int OBJ_ln2nid(const char *ln);
  13. int OBJ_sn2nid(const char *sn);
  14. int OBJ_txt2nid(const char *s);
  15. ASN1_OBJECT * OBJ_txt2obj(const char *s, int no_name);
  16. int OBJ_obj2txt(char *buf, int buf_len, const ASN1_OBJECT *a, int no_name);
  17. int OBJ_cmp(const ASN1_OBJECT *a,const ASN1_OBJECT *b);
  18. ASN1_OBJECT * OBJ_dup(const ASN1_OBJECT *o);
  19. int OBJ_create(const char *oid,const char *sn,const char *ln);
  20. void OBJ_cleanup(void);
  21. =head1 DESCRIPTION
  22. The ASN1 object utility functions process ASN1_OBJECT structures which are
  23. a representation of the ASN1 OBJECT IDENTIFIER (OID) type.
  24. OBJ_nid2obj(), OBJ_nid2ln() and OBJ_nid2sn() convert the NID B<n> to
  25. an ASN1_OBJECT structure, its long name and its short name respectively,
  26. or B<NULL> is an error occurred.
  27. OBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() return the corresponding NID
  28. for the object B<o>, the long name <ln> or the short name <sn> respectively
  29. or NID_undef if an error occurred.
  30. OBJ_txt2nid() returns NID corresponding to text string <s>. B<s> can be
  31. a long name, a short name or the numerical respresentation of an object.
  32. OBJ_txt2obj() converts the text string B<s> into an ASN1_OBJECT structure.
  33. If B<no_name> is 0 then long names and short names will be interpreted
  34. as well as numerical forms. If B<no_name> is 1 only the numerical form
  35. is acceptable.
  36. OBJ_obj2txt() converts the B<ASN1_OBJECT> B<a> into a textual representation.
  37. The representation is written as a null terminated string to B<buf>
  38. at most B<buf_len> bytes are written, truncating the result if necessary.
  39. The total amount of space required is returned. If B<no_name> is 0 then
  40. if the object has a long or short name then that will be used, otherwise
  41. the numerical form will be used. If B<no_name> is 1 then the numerical
  42. form will always be used.
  43. OBJ_cmp() compares B<a> to B<b>. If the two are identical 0 is returned.
  44. OBJ_dup() returns a copy of B<o>.
  45. OBJ_create() adds a new object to the internal table. B<oid> is the
  46. numerical form of the object, B<sn> the short name and B<ln> the
  47. long name. A new NID is returned for the created object.
  48. OBJ_cleanup() cleans up OpenSSLs internal object table: this should
  49. be called before an application exits if any new objects were added
  50. using OBJ_create().
  51. =head1 NOTES
  52. Objects in OpenSSL can have a short name, a long name and a numerical
  53. identifier (NID) associated with them. A standard set of objects is
  54. represented in an internal table. The appropriate values are defined
  55. in the header file B<objects.h>.
  56. For example the OID for commonName has the following definitions:
  57. #define SN_commonName "CN"
  58. #define LN_commonName "commonName"
  59. #define NID_commonName 13
  60. New objects can be added by calling OBJ_create().
  61. Table objects have certain advantages over other objects: for example
  62. their NIDs can be used in a C language switch statement. They are
  63. also static constant structures which are shared: that is there
  64. is only a single constant structure for each table object.
  65. Objects which are not in the table have the NID value NID_undef.
  66. Objects do not need to be in the internal tables to be processed,
  67. the functions OBJ_txt2obj() and OBJ_obj2txt() can process the numerical
  68. form of an OID.
  69. =head1 EXAMPLES
  70. Create an object for B<commonName>:
  71. ASN1_OBJECT *o;
  72. o = OBJ_nid2obj(NID_commonName);
  73. Check if an object is B<commonName>
  74. if (OBJ_obj2nid(obj) == NID_commonName)
  75. /* Do something */
  76. Create a new NID and initialize an object from it:
  77. int new_nid;
  78. ASN1_OBJECT *obj;
  79. new_nid = OBJ_create("1.2.3.4", "NewOID", "New Object Identifier");
  80. obj = OBJ_nid2obj(new_nid);
  81. Create a new object directly:
  82. obj = OBJ_txt2obj("1.2.3.4", 1);
  83. =head1 BUGS
  84. OBJ_obj2txt() is awkward and messy to use: it doesn't follow the
  85. convention of other OpenSSL functions where the buffer can be set
  86. to B<NULL> to determine the amount of data that should be written.
  87. Instead B<buf> must point to a valid buffer and B<buf_len> should
  88. be set to a positive value. A buffer length of 80 should be more
  89. than enough to handle any OID encountered in practice.
  90. =head1 RETURN VALUES
  91. OBJ_nid2obj() returns an B<ASN1_OBJECT> structure or B<NULL> is an
  92. error occurred.
  93. OBJ_nid2ln() and OBJ_nid2sn() returns a valid string or B<NULL>
  94. on error.
  95. OBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() and OBJ_txt2nid() return
  96. a NID or B<NID_undef> on error.
  97. =head1 SEE ALSO
  98. L<ERR_get_error(3)|ERR_get_error(3)>
  99. =head1 HISTORY
  100. TBA
  101. =cut