1=pod 2 3=head1 NAME 4 5X509_new, X509_new_ex, 6X509_free, X509_up_ref, 7X509_chain_up_ref, 8OSSL_STACK_OF_X509_free 9- X509 certificate ASN1 allocation and deallocation functions 10 11=head1 SYNOPSIS 12 13 #include <openssl/x509.h> 14 15 X509 *X509_new(void); 16 X509 *X509_new_ex(OSSL_LIB_CTX *libctx, const char *propq); 17 void X509_free(X509 *a); 18 int X509_up_ref(X509 *a); 19 STACK_OF(X509) *X509_chain_up_ref(STACK_OF(X509) *x); 20 void OSSL_STACK_OF_X509_free(STACK_OF(X509) *certs); 21 22=head1 DESCRIPTION 23 24The X509 ASN1 allocation routines allocate and free an 25X509 structure, which represents an X509 certificate. 26 27X509_new_ex() allocates and initializes a X509 structure with a 28library context of I<libctx>, property query of I<propq> and a reference 29count of B<1>. Many X509 functions such as X509_check_purpose(), and 30X509_verify() use this library context to select which providers supply the 31fetched algorithms (SHA1 is used internally). This created X509 object can then 32be used when loading binary data using d2i_X509(). 33 34X509_new() is similar to X509_new_ex() but sets the library context 35and property query to NULL. This results in the default (NULL) library context 36being used for any X509 operations requiring algorithm fetches. 37 38X509_free() decrements the reference count of B<X509> structure B<a> and 39frees it up if the reference count is zero. If the argument is NULL, 40nothing is done. 41 42X509_up_ref() increments the reference count of B<a>. 43 44X509_chain_up_ref() increases the reference count of all certificates in 45chain B<x> and returns a copy of the stack, or an empty stack if B<a> is NULL. 46 47OSSL_STACK_OF_X509_free() deallocates the given list of pointers to 48certificates after calling X509_free() on all its elements. 49If the argument is NULL, nothing is done. 50 51=head1 NOTES 52 53The function X509_up_ref() if useful if a certificate structure is being 54used by several different operations each of which will free it up after 55use: this avoids the need to duplicate the entire certificate structure. 56 57The function X509_chain_up_ref() doesn't just up the reference count of 58each certificate. It also returns a copy of the stack, using sk_X509_dup(), 59but it serves a similar purpose: the returned chain persists after the 60original has been freed. 61 62=head1 RETURN VALUES 63 64If the allocation fails, X509_new() returns NULL and sets an error 65code that can be obtained by L<ERR_get_error(3)>. 66Otherwise it returns a pointer to the newly allocated structure. 67 68X509_up_ref() returns 1 for success and 0 for failure. 69 70X509_chain_up_ref() returns a copy of the stack or NULL if an error occurred. 71 72OSSL_STACK_OF_X509_free() has no return value. 73 74=head1 SEE ALSO 75 76L<d2i_X509(3)>, 77L<ERR_get_error(3)>, 78L<X509_CRL_get0_by_serial(3)>, 79L<X509_get0_signature(3)>, 80L<X509_get_ext_d2i(3)>, 81L<X509_get_extension_flags(3)>, 82L<X509_get_pubkey(3)>, 83L<X509_get_subject_name(3)>, 84L<X509_get_version(3)>, 85L<X509_NAME_add_entry_by_txt(3)>, 86L<X509_NAME_ENTRY_get_object(3)>, 87L<X509_NAME_get_index_by_NID(3)>, 88L<X509_NAME_print_ex(3)>, 89L<X509_sign(3)>, 90L<X509V3_get_d2i(3)>, 91L<X509_verify_cert(3)> 92 93=head1 HISTORY 94 95X509_new_ex() was added in OpenSSL 3.0. 96 97OSSL_STACK_OF_X509_free() was added in OpenSSL 3.2. 98 99=head1 COPYRIGHT 100 101Copyright 2002-2024 The OpenSSL Project Authors. All Rights Reserved. 102 103Licensed under the Apache License 2.0 (the "License"). You may not use 104this file except in compliance with the License. You can obtain a copy 105in the file LICENSE in the source distribution or at 106L<https://www.openssl.org/source/license.html>. 107 108=cut 109
