=head1 NAME
-CRYPTO_set_locking_callback, CRYPTO_set_id_callback - OpenSSL thread support
+CRYPTO_set_locking_callback, CRYPTO_set_id_callback, CRYPTO_num_locks,
+CRYPTO_set_dynlock_create_callback, CRYPTO_set_dynlock_lock_callback,
+CRYPTO_set_dynlock_destroy_callback, CRYPTO_get_new_dynlockid,
+CRYPTO_destroy_dynlockid, CRYPTO_lock - OpenSSL thread support
=head1 SYNOPSIS
void CRYPTO_set_id_callback(unsigned long (*id_function)(void));
+ int CRYPTO_num_locks(void);
+
+
+ /* struct CRYPTO_dynlock_value needs to be defined by the user */
+ struct CRYPTO_dynlock_value;
+
+ void CRYPTO_set_dynlock_create_callback(struct CRYPTO_dynlock_value *
+ (*dyn_create_function)(char *file, int line));
+ void CRYPTO_set_dynlock_lock_callback(void (*dyn_lock_function)
+ (int mode, struct CRYPTO_dynlock_value *l,
+ const char *file, int line));
+ void CRYPTO_set_dynlock_destroy_callback(void (*dyn_destroy_function)
+ (struct CRYPTO_dynlock_value *l, const char *file, int line));
+
+ int CRYPTO_get_new_dynlockid(void);
+
+ void CRYPTO_destroy_dynlockid(int i);
+
+ void CRYPTO_lock(int mode, int n, const char *file, int line);
+
+ #define CRYPTO_w_lock(type) \
+ CRYPTO_lock(CRYPTO_LOCK|CRYPTO_WRITE,type,__FILE__,__LINE__)
+ #define CRYPTO_w_unlock(type) \
+ CRYPTO_lock(CRYPTO_UNLOCK|CRYPTO_WRITE,type,__FILE__,__LINE__)
+ #define CRYPTO_r_lock(type) \
+ CRYPTO_lock(CRYPTO_LOCK|CRYPTO_READ,type,__FILE__,__LINE__)
+ #define CRYPTO_r_unlock(type) \
+ CRYPTO_lock(CRYPTO_UNLOCK|CRYPTO_READ,type,__FILE__,__LINE__)
+ #define CRYPTO_add(addr,amount,type) \
+ CRYPTO_add_lock(addr,amount,type,__FILE__,__LINE__)
+
=head1 DESCRIPTION
OpenSSL can safely be used in multi-threaded applications provided
-that two callback functions are set.
+that at least two callback functions are set.
-locking_function(int mode, int type, const char *file, int line) is
-needed to perform locking on shared data stuctures. Multi-threaded
-applications will crash at random if it is not set.
+locking_function(int mode, int n, const char *file, int line) 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.
-locking_function() must be able to handle up to B<CRYPTO_NUM_LOCKS>
-different mutex locks. It sets the B<n>th lock if B<mode> &
+locking_function() must be able to handle up to CRYPTO_num_locks()
+different mutex locks. It sets the B<n>-th lock if B<mode> &
B<CRYPTO_LOCK>, and releases it otherwise.
B<file> and B<line> are the file number of the function setting the
id_function(void) is a function that returns a thread ID. It is not
needed on Windows nor on platforms where getpid() returns a different
-ID for each thread.
+ID for each thread (most notably Linux).
+
+Additionally, OpenSSL supports dynamic locks, and sometimes, some parts
+of OpenSSL need it for better performance. To enable this, the following
+is required:
+
+=over 4
+
+=item *
+Three additional callback function, dyn_create_function, dyn_lock_function
+and dyn_destroy_function.
+
+=item *
+A structure defined with the data that each lock needs to handle.
+
+=back
-=NOTE
+struct CRYPTO_dynlock_value has to be defined to contain whatever structure
+is needed to handle locks.
+
+dyn_create_function(const char *file, int line) is needed to create a
+lock. Multi-threaded applications might crash at random if it is not set.
+
+dyn_lock_function(int mode, CRYPTO_dynlock *l, const char *file, int line)
+is needed to perform locking off dynamic lock numbered n. Multi-threaded
+applications might crash at random if it is not set.
+
+dyn_destroy_function(CRYPTO_dynlock *l, const char *file, int line) is
+needed to destroy the lock l. Multi-threaded applications might crash at
+random if it is not set.
+
+CRYPTO_get_new_dynlockid() is used to create locks. It will call
+dyn_create_function for the actual creation.
+
+CRYPTO_destroy_dynlockid() is used to destroy locks. It will call
+dyn_destroy_function for the actual destruction.
+
+CRYPTO_lock() is used to lock and unlock the locks. mode is a bitfield
+describing what should be done with the lock. n is the number of the
+lock as returned from CRYPTO_get_new_dynlockid(). mode can be combined
+from the following values. These values are pairwise exclusive, with
+undefined behaviour if misused (for example, CRYPTO_READ and CRYPTO_WRITE
+should not be used together):
+
+ CRYPTO_LOCK 0x01
+ CRYPTO_UNLOCK 0x02
+ CRYPTO_READ 0x04
+ CRYPTO_WRITE 0x08
+
+=head1 RETURN VALUES
+
+CRYPTO_num_locks() returns the required number of locks.
+
+CRYPTO_get_new_dynlockid() returns the index to the newly created lock.
+
+The other functions return no values.
+
+=head1 NOTE
You can find out if OpenSSL was configured with thread support:
#define OPENSSL_THREAD_DEFINES
#include <openssl/opensslconf.h>
- #if defined(THREADS)
+ #if defined(OPENSSL_THREADS)
// thread support enabled
#else
// no thread support
#endif
+Also, dynamic locks are currently not used internally by OpenSSL, but
+may do so in the future.
+
=head1 EXAMPLES
B<crypto/threads/mttest.c> shows examples of the callback functions on
CRYPTO_set_locking_callback() and CRYPTO_set_id_callback() are
available in all versions of SSLeay and OpenSSL.
+CRYPTO_num_locks() was added in OpenSSL 0.9.4.
+All functions dealing with dynamic locks were added in OpenSSL 0.9.5b-dev.
=head1 SEE ALSO
projects / openssl.git / blobdiff