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Diffstat (limited to 'openssl/trunk/doc/crypto/threads.pod')
| -rw-r--r-- | openssl/trunk/doc/crypto/threads.pod | 175 |
1 files changed, 0 insertions, 175 deletions
diff --git a/openssl/trunk/doc/crypto/threads.pod b/openssl/trunk/doc/crypto/threads.pod deleted file mode 100644 index 3df4ecd7..00000000 --- a/openssl/trunk/doc/crypto/threads.pod +++ /dev/null @@ -1,175 +0,0 @@ -=pod - -=head1 NAME - -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 - - #include <openssl/crypto.h> - - void CRYPTO_set_locking_callback(void (*locking_function)(int mode, - int n, const char *file, int line)); - - 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 at least two callback functions are 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 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 -lock. They can be useful for debugging. - -id_function(void) is a function that returns a thread ID, for example -pthread_self() if it returns an integer (see NOTES below). It isn't -needed on Windows nor on platforms where getpid() returns a different -ID for each thread (see NOTES below). - -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 - -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 NOTES - -You can find out if OpenSSL was configured with thread support: - - #define OPENSSL_THREAD_DEFINES - #include <openssl/opensslconf.h> - #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. - -Defining id_function(void) has it's own issues. Generally speaking, -pthread_self() should be used, even on platforms where getpid() gives -different answers in each thread, since that may depend on the machine -the program is run on, not the machine where the program is being -compiled. For instance, Red Hat 8 Linux and earlier used -LinuxThreads, whose getpid() returns a different value for each -thread. Red Hat 9 Linux and later use NPTL, which is -Posix-conformant, and has a getpid() that returns the same value for -all threads in a process. A program compiled on Red Hat 8 and run on -Red Hat 9 will therefore see getpid() returning the same value for -all threads. - -There is still the issue of platforms where pthread_self() returns -something other than an integer. This is a bit unusual, and this -manual has no cookbook solution for that case. - -=head1 EXAMPLES - -B<crypto/threads/mttest.c> shows examples of the callback functions on -Solaris, Irix and Win32. - -=head1 HISTORY - -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 - -L<crypto(3)|crypto(3)> - -=cut |