SSL_SESSION_free.3ossl 7.4 KB

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  133. .\" ========================================================================
  134. .\"
  135. .IX Title "SSL_SESSION_FREE 3ossl"
  136. .TH SSL_SESSION_FREE 3ossl "2024-09-03" "3.3.2" "OpenSSL"
  137. .\" For nroff, turn off justification. Always turn off hyphenation; it makes
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  139. .if n .ad l
  140. .nh
  141. .SH "NAME"
  142. SSL_SESSION_new,
  143. SSL_SESSION_dup,
  144. SSL_SESSION_up_ref,
  145. SSL_SESSION_free \- create, free and manage SSL_SESSION structures
  146. .SH "SYNOPSIS"
  147. .IX Header "SYNOPSIS"
  148. .Vb 1
  149. \& #include <openssl/ssl.h>
  150. \&
  151. \& SSL_SESSION *SSL_SESSION_new(void);
  152. \& SSL_SESSION *SSL_SESSION_dup(const SSL_SESSION *src);
  153. \& int SSL_SESSION_up_ref(SSL_SESSION *ses);
  154. \& void SSL_SESSION_free(SSL_SESSION *session);
  155. .Ve
  156. .SH "DESCRIPTION"
  157. .IX Header "DESCRIPTION"
  158. \&\fBSSL_SESSION_new()\fR creates a new \s-1SSL_SESSION\s0 structure and returns a pointer to
  159. it.
  160. .PP
  161. \&\fBSSL_SESSION_dup()\fR creates a new \s-1SSL_SESSION\s0 structure that is a copy of \fBsrc\fR.
  162. The copy is not owned by any cache that \fBsrc\fR may have been in.
  163. .PP
  164. \&\fBSSL_SESSION_up_ref()\fR increments the reference count on the given \s-1SSL_SESSION\s0
  165. structure.
  166. .PP
  167. \&\fBSSL_SESSION_free()\fR decrements the reference count of \fBsession\fR and removes
  168. the \fB\s-1SSL_SESSION\s0\fR structure pointed to by \fBsession\fR and frees up the allocated
  169. memory, if the reference count has reached 0.
  170. If \fBsession\fR is \s-1NULL\s0 nothing is done.
  171. .SH "NOTES"
  172. .IX Header "NOTES"
  173. \&\s-1SSL_SESSION\s0 objects are allocated, when a \s-1TLS/SSL\s0 handshake operation
  174. is successfully completed. Depending on the settings, see
  175. \&\fBSSL_CTX_set_session_cache_mode\fR\|(3),
  176. the \s-1SSL_SESSION\s0 objects are internally referenced by the \s-1SSL_CTX\s0 and
  177. linked into its session cache. \s-1SSL\s0 objects may be using the \s-1SSL_SESSION\s0 object;
  178. as a session may be reused, several \s-1SSL\s0 objects may be using one \s-1SSL_SESSION\s0
  179. object at the same time. It is therefore crucial to keep the reference
  180. count (usage information) correct and not delete a \s-1SSL_SESSION\s0 object
  181. that is still used, as this may lead to program failures due to
  182. dangling pointers. These failures may also appear delayed, e.g.
  183. when an \s-1SSL_SESSION\s0 object was completely freed as the reference count
  184. incorrectly became 0, but it is still referenced in the internal
  185. session cache and the cache list is processed during a
  186. \&\fBSSL_CTX_flush_sessions\fR\|(3) operation.
  187. .PP
  188. \&\fBSSL_SESSION_free()\fR must only be called for \s-1SSL_SESSION\s0 objects, for
  189. which the reference count was explicitly incremented (e.g.
  190. by calling \fBSSL_get1_session()\fR, see \fBSSL_get_session\fR\|(3))
  191. or when the \s-1SSL_SESSION\s0 object was generated outside a \s-1TLS\s0 handshake
  192. operation, e.g. by using \fBd2i_SSL_SESSION\fR\|(3).
  193. It must not be called on other \s-1SSL_SESSION\s0 objects, as this would cause
  194. incorrect reference counts and therefore program failures.
  195. .SH "RETURN VALUES"
  196. .IX Header "RETURN VALUES"
  197. SSL_SESSION_new returns a pointer to the newly allocated \s-1SSL_SESSION\s0 structure
  198. or \s-1NULL\s0 on error.
  199. .PP
  200. SSL_SESSION_dup returns a pointer to the new copy or \s-1NULL\s0 on error.
  201. .PP
  202. SSL_SESSION_up_ref returns 1 on success or 0 on error.
  203. .SH "SEE ALSO"
  204. .IX Header "SEE ALSO"
  205. \&\fBssl\fR\|(7), \fBSSL_get_session\fR\|(3),
  206. \&\fBSSL_CTX_set_session_cache_mode\fR\|(3),
  207. \&\fBSSL_CTX_flush_sessions\fR\|(3),
  208. \&\fBd2i_SSL_SESSION\fR\|(3)
  209. .SH "HISTORY"
  210. .IX Header "HISTORY"
  211. The \fBSSL_SESSION_dup()\fR function was added in OpenSSL 1.1.1.
  212. .SH "COPYRIGHT"
  213. .IX Header "COPYRIGHT"
  214. Copyright 2000\-2023 The OpenSSL Project Authors. All Rights Reserved.
  215. .PP
  216. Licensed under the Apache License 2.0 (the \*(L"License\*(R"). You may not use
  217. this file except in compliance with the License. You can obtain a copy
  218. in the file \s-1LICENSE\s0 in the source distribution or at
  219. <https://www.openssl.org/source/license.html>.