.\" $OpenBSD: CRYPTO_set_locking_callback.3,v 1.10 2018/03/27 17:35:50 schwarze Exp $ .\" OpenSSL doc/crypto/threads.pod fb552ac6 Sep 30 23:43:01 2009 +0000 .\" .\" This file was written by Ulf Moeller , .\" Richard Levitte , Bodo Moeller , .\" and Geoff Thorpe . .\" Copyright (c) 2000, 2001, 2005, 2006, 2008, 2009 The OpenSSL Project. .\" All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in .\" the documentation and/or other materials provided with the .\" distribution. .\" .\" 3. 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IN NO EVENT SHALL THE OpenSSL PROJECT OR .\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, .\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; .\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, .\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED .\" OF THE POSSIBILITY OF SUCH DAMAGE. .\" .Dd $Mdocdate: March 27 2018 $ .Dt CRYPTO_SET_LOCKING_CALLBACK 3 .Os .Sh NAME .Nm CRYPTO_THREADID_set_numeric , .Nm CRYPTO_THREADID_set_pointer , .Nm CRYPTO_THREADID_set_callback , .Nm CRYPTO_THREADID_get_callback , .Nm CRYPTO_THREADID_current , .Nm CRYPTO_THREADID_cmp , .Nm CRYPTO_THREADID_cpy , .Nm CRYPTO_THREADID_hash , .Nm CRYPTO_num_locks , .Nm CRYPTO_set_dynlock_create_callback , .Nm CRYPTO_set_dynlock_lock_callback , .Nm CRYPTO_set_dynlock_destroy_callback , .Nm CRYPTO_get_new_dynlockid , .Nm CRYPTO_destroy_dynlockid , .Nm CRYPTO_lock , .Nm CRYPTO_w_lock , .Nm CRYPTO_w_unlock , .Nm CRYPTO_r_lock , .Nm CRYPTO_r_unlock , .Nm CRYPTO_add .Nd OpenSSL thread support .Sh SYNOPSIS .In openssl/crypto.h .Bd -literal /* Don't use this structure directly. */ typedef struct crypto_threadid_st { void *ptr; unsigned long val; } CRYPTO_THREADID; /* Only use CRYPTO_THREADID_set_[numeric|pointer]() within callbacks */ .Ed .Pp .Ft void .Fo CRYPTO_THREADID_set_numeric .Fa "CRYPTO_THREADID *id" .Fa "unsigned long val" .Fc .Ft void .Fo CRYPTO_THREADID_set_pointer .Fa "CRYPTO_THREADID *id" .Fa "void *ptr" .Fc .Ft int .Fo CRYPTO_THREADID_set_callback .Fa "void (*threadid_func)(CRYPTO_THREADID *)" .Fc .Ft void .Fo "(*CRYPTO_THREADID_get_callback(void))" .Fa "CRYPTO_THREADID *" .Fc .Ft void .Fo CRYPTO_THREADID_current .Fa "CRYPTO_THREADID *id" .Fc .Ft int .Fo CRYPTO_THREADID_cmp .Fa "const CRYPTO_THREADID *a" .Fa "const CRYPTO_THREADID *b" .Fc .Ft void .Fo CRYPTO_THREADID_cpy .Fa "CRYPTO_THREADID *dest" .Fa "const CRYPTO_THREADID *src" .Fc .Ft unsigned long .Fo CRYPTO_THREADID_hash .Fa "const CRYPTO_THREADID *id" .Fc .Ft int .Fo CRYPTO_num_locks .Fa void .Fc .Bd -literal /* struct CRYPTO_dynlock_value needs to be defined by the user */ struct CRYPTO_dynlock_value; .Ed .Pp .Ft void .Fo CRYPTO_set_dynlock_create_callback .Fa "struct CRYPTO_dynlock_value *" .Fa "(*dyn_create_function)(char *file, int line)" .Fc .Ft void .Fo CRYPTO_set_dynlock_lock_callback .Fa "void (*dyn_lock_function)(int mode, struct CRYPTO_dynlock_value *l,\ const char *file, int line)" .Fc .Ft void .Fo CRYPTO_set_dynlock_destroy_callback .Fa "void (*dyn_destroy_function)(struct CRYPTO_dynlock_value *l,\ const char *file, int line)" .Fc .Ft int .Fo CRYPTO_get_new_dynlockid .Fa void .Fc .Ft void .Fo CRYPTO_destroy_dynlockid .Fa "int i" .Fc .Ft void .Fo CRYPTO_lock .Fa "int mode" .Fa "int n" .Fa "const char *file" .Fa "int line" .Fc .Bd -literal #define CRYPTO_w_lock(type) \e CRYPTO_lock(CRYPTO_LOCK|CRYPTO_WRITE, type, __FILE__, __LINE__) #define CRYPTO_w_unlock(type) \e CRYPTO_lock(CRYPTO_UNLOCK|CRYPTO_WRITE, type, __FILE__, __LINE__) #define CRYPTO_r_lock(type) \e CRYPTO_lock(CRYPTO_LOCK|CRYPTO_READ, type, __FILE__, __LINE__) #define CRYPTO_r_unlock(type) \e CRYPTO_lock(CRYPTO_UNLOCK|CRYPTO_READ, type, __FILE__, __LINE__) #define CRYPTO_add(addr,amount,type) \e CRYPTO_add_lock(addr, amount, type, __FILE__, __LINE__) .Ed .Sh DESCRIPTION OpenSSL can safely be used in multi-threaded applications provided that at least two callback functions are set, .Fn locking_function and .Fn threadid_func . .Pp .Fo locking_function .Fa "int mode" .Fa "int n" .Fa "const char *file" .Fa "int line" .Fc is needed to perform locking on shared data structures. Note that OpenSSL uses a number of global data structures that will be implicitly shared whenever multiple threads use OpenSSL. Multi-threaded applications will crash at random if it is not set. .Pp .Fn locking_function must be able to handle up to .Fn CRYPTO_num_locks different mutex locks. It sets the .Fa n Ns -th lock if .Fa mode includes .Dv CRYPTO_LOCK , and releases it otherwise. .Pp .Fa file and .Fa line are the file number of the function setting the lock. They can be useful for debugging. .Pp .Fo threadid_func .Fa "CRYPTO_THREADID *id" .Fc is needed to record the currently-executing thread's identifier into .Fa id . The implementation of this callback should not fill in .Fa id directly, but should use .Fn CRYPTO_THREADID_set_numeric if thread IDs are numeric, or .Fn CRYPTO_THREADID_set_pointer if they are pointer-based. If the application does not register such a callback using .Fn CRYPTO_THREADID_set_callback , then a default implementation is used - on Windows and BeOS this uses the system's default thread identifying APIs, and on all other platforms it uses the address of .Va errno . The latter is satisfactory for thread-safety if and only if the platform has a thread-local error number facility. .Pp Once .Fn threadid_func is registered, or if the built-in default implementation is to be used, .Bl -bullet .It .Fn CRYPTO_THREADID_current records the currently-executing thread ID into the given .Fa id object. .It .Fn CRYPTO_THREADID_cmp compares two thread IDs (returning zero for equality, i.e. the same semantics as .Xr memcmp 3 ) . .It .Fn CRYPTO_THREADID_cpy duplicates a thread ID value. .It .Fn CRYPTO_THREADID_hash returns a numeric value usable as a hash-table key. This is usually the exact numeric or pointer-based thread ID used internally, however this also handles the unusual case where pointers are larger than .Vt long variables and the platform's thread IDs are pointer-based \(em in this case, mixing is done to attempt to produce a unique numeric value even though it is not as wide as the platform's true thread IDs. .El .Pp Additionally, OpenSSL supports dynamic locks and, sometimes, some parts of OpenSSL need it for better performance. To enable this, the following is required: .Bl -bullet .It Three additional callback functions, .Fn dyn_create_function , .Fn dyn_lock_function , and .Fn dyn_destroy_function . .It A structure defined with the data that each lock needs to handle. .El .Pp .Vt struct CRYPTO_dynlock_value has to be defined to contain whatever structure is needed to handle locks. .Pp .Fo dyn_create_function .Fa "const char *file" .Fa "int line" .Fc is needed to create a lock. Multi-threaded applications might crash at random if it is not set. .Pp .Fo dyn_lock_function .Fa "int mode" .Fa "CRYPTO_dynlock *l" .Fa "const char *file" .Fa "int line" .Fc is needed to perform locking off dynamic lock numbered n. Multi-threaded applications might crash at random if it is not set. .Pp .Fo dyn_destroy_function .Fa "CRYPTO_dynlock *l" .Fa "const char *file" .Fa "int line" .Fc is needed to destroy the lock .Fa l . Multi-threaded applications might crash at random if it is not set. .Pp .Fn CRYPTO_get_new_dynlockid is used to create locks. It will call .Fn dyn_create_function for the actual creation. .Pp .Fn CRYPTO_destroy_dynlockid is used to destroy locks. It will call .Fn dyn_destroy_function for the actual destruction. .Pp .Fn CRYPTO_lock is used to lock and unlock the locks. .Fa mode is a bitfield describing what should be done with the lock. .Fa n is the number of the lock as returned from .Fn CRYPTO_get_new_dynlockid . .Fa mode can be combined from the following values. These values are pairwise exclusive, with undefined behaviour if misused (for example, .Dv CRYPTO_READ and .Dv CRYPTO_WRITE should not be used together): .Bd -literal -offset indent CRYPTO_LOCK 0x01 CRYPTO_UNLOCK 0x02 CRYPTO_READ 0x04 CRYPTO_WRITE 0x08 .Ed .Pp You can find out if OpenSSL was configured with thread support: .Bd -literal -offset indent #define OPENSSL_THREAD_DEFINES #include #if defined(OPENSSL_THREADS) /* thread support enabled */ #else /* no thread support */ #endif .Ed .Pp Also, dynamic locks are currently not used internally by OpenSSL, but may do so in the future. .Sh RETURN VALUES .Fn CRYPTO_num_locks returns the required number of locks. .Pp .Fn CRYPTO_get_new_dynlockid returns the index to the newly created lock. .Pp The other functions return no values. .Sh EXAMPLES .Pa crypto/threads/mttest.c shows examples of the callback functions on Solaris, Irix and Win32. .Sh SEE ALSO .Xr crypto 3 .Sh HISTORY .Fn CRYPTO_set_locking_callback , .Fn CRYPTO_lock , .Fn CRYPTO_w_lock , .Fn CRYPTO_w_unlock , .Fn CRYPTO_r_lock , and .Fn CRYPTO_r_unlock first appeared in SSLeay 0.6.0. .Fn CRYPTO_add first appeared in SSLeay 0.6.2. These functions have been available since .Ox 2.4 . .Pp .Fn CRYPTO_num_locks first appeared in OpenSSL 0.9.4 and have been available since .Ox 2.6 . .Pp .Fn CRYPTO_set_dynlock_create_callback , .Fn CRYPTO_set_dynlock_lock_callback , .Fn CRYPTO_set_dynlock_destroy_callback , .Fn CRYPTO_get_new_dynlockid , and .Fn CRYPTO_destroy_dynlockid first appeared in OpenSSL 0.9.6 and have been available since .Ox 2.9 . .Pp .Fn CRYPTO_THREADID_set_numeric , .Fn CRYPTO_THREADID_set_pointer , .Fn CRYPTO_THREADID_set_callback , .Fn CRYPTO_THREADID_get_callback , .Fn CRYPTO_THREADID_current , .Fn CRYPTO_THREADID_cmp , .Fn CRYPTO_THREADID_cpy , and .Fn CRYPTO_THREADID_hash first appeared in OpenSSL 1.0.0 and have been available since .Ox 4.9 .