NAME¶

X509_PURPOSE_set, X509_PURPOSE_get_by_id, X509_PURPOSE_add, X509_PURPOSE_get_count, X509_PURPOSE_cleanup, X509_PURPOSE_get0, X509_PURPOSE_get_by_sname, X509_PURPOSE_get_id, X509_PURPOSE_get0_name, X509_PURPOSE_get0_sname, X509_PURPOSE_get_trust — purpose objects, indices, and identifiers

SYNOPSIS¶

#include <openssl/x509v3.h>

int
X509_PURPOSE_set(int *id_out, int id_in);

int
X509_PURPOSE_get_by_id(int identifier);

int
X509_PURPOSE_add(int identifier, int trust, int flags, int (*check_purpose)(const X509_PURPOSE *, const X509 *, int), const char *name, const char *sname, void *usr_data);

int
X509_PURPOSE_get_count(void);

void
X509_PURPOSE_cleanup(void);

X509_PURPOSE *
X509_PURPOSE_get0(int index);

int
X509_PURPOSE_get_by_sname(const char *sname);

int
X509_PURPOSE_get_id(const X509_PURPOSE *object);

char *
X509_PURPOSE_get0_name(const X509_PURPOSE *object);

char *
X509_PURPOSE_get0_sname(const X509_PURPOSE *object);

int
X509_PURPOSE_get_trust(const X509_PURPOSE *object);

DESCRIPTION¶

The purposes that an X.509 certificate is intended to be used for can be identified in three equivalent ways:

1. By purpose identifiers, which are positive integer constants. Standard purpose identifiers lie in the range from X509_PURPOSE_MIN to X509_PURPOSE_MAX, inclusive, and are listed in the X509_check_purpose(3) manual page. User defined purpose identifiers are larger than X509_PURPOSE_MAX.
2. By purpose indices, which are non-negative integer constants but differ from the purpose identifiers for the same purpose. Standard purpose indices are smaller than X509_PURPOSE_MAX. User defined purpose indices are larger than or equal to X509_PURPOSE_MAX.
3. By purpose objects of the type X509_PURPOSE. Standard purpose objects are available in static storage. User defined purpose objects can be created with X509_PURPOSE_add().

Application programmers cannot choose the way to identify purposes that they like best; depending on the circumstances, all three ways are needed. Be warned that the naming of most functions is misleading.

Most API functions documented outside the present manual page use purpose identifiers rather than purpose indices.

RETURN VALUES¶

X509_PURPOSE_set() returns 1 if id_in is valid or 0 otherwise.

X509_PURPOSE_get_by_id() and X509_PURPOSE_get_by_sname() return the corresponding purpose index or -1 if no matching purpose is found.

X509_PURPOSE_add() returns 1 for success or 0 for failure.

X509_PURPOSE_get_count() returns the total number of purposes currently defined.

X509_PURPOSE_get0() returns a standard or user-defined purpose object or NULL if the index is invalid.

X509_PURPOSE_get_id() always returns a valid purpose identifier.

X509_PURPOSE_get0_name() and X509_PURPOSE_get0_sname() return pointers to storage owned by the object.

X509_PURPOSE_get_trust() returns the trust identifier associated with the object.

ERRORS¶

The following diagnostics can be retrieved with ERR_get_error(3), ERR_GET_REASON(3), and ERR_reason_error_string(3):

X509V3_R_INVALID_PURPOSE "invalid purpose"

X509_PURPOSE_set() was called with an invalid id_in argument.

X509V3_R_INVALID_NULL_ARGUMENT "invalid null argument"

X509_PURPOSE_add() was called with a name or sname argument of NULL.

ERR_R_MALLOC_FAILURE "malloc failure"

X509_PURPOSE_add() failed to allocate memory.

The other functions provide no diagnostics.

SEE ALSO¶

X509_check_purpose(3), X509_new(3), X509_STORE_set_purpose(3), X509_VERIFY_PARAM_set_purpose(3)

HISTORY¶

X509_PURPOSE_set() first appeared in OpenSSL 0.9.7 and has been available since OpenBSD 3.2.

The other functions first appeared in OpenSSL 0.9.5 and have been available since OpenBSD 2.7.

CAVEATS¶

The difference between purpose identifiers and purpose indices provides an ideal breeding ground for off-by-one bugs.