Implement new multi-threading API

Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>

1 files changed, 31 insertions, 156 deletions

diff --git a/doc/crypto/threads.pod b/doc/crypto/threads.pod
index 9ee75b3843..90c57098a4 100644
--- a/doc/crypto/threads.pod
+++ b/doc/crypto/threads.pod
@@ -2,176 +2,66 @@
 
 =head1 NAME
 
-CRYPTO_THREADID_set_callback, CRYPTO_THREADID_get_callback,
-CRYPTO_THREADID_current, CRYPTO_THREADID_cmp, CRYPTO_THREADID_cpy,
-CRYPTO_THREADID_hash, CRYPTO_set_locking_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
+CRYPTO_THREAD_lock_new, CRYPTO_THREAD_read_lock, CRYPTO_THREAD_write_lock,
+CRYPTO_THREAD_unlock, CRYPTO_THREAD_lock_free, CRYPTO_atomic_add - OpenSSL thread support
 
 =head1 SYNOPSIS
 
  #include <openssl/crypto.h>
 
- /* 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 */
- void CRYPTO_THREADID_set_numeric(CRYPTO_THREADID *id, unsigned long val);
- void CRYPTO_THREADID_set_pointer(CRYPTO_THREADID *id, void *ptr);
- int CRYPTO_THREADID_set_callback(void (*threadid_func)(CRYPTO_THREADID *));
- void (*CRYPTO_THREADID_get_callback(void))(CRYPTO_THREADID *);
- void CRYPTO_THREADID_current(CRYPTO_THREADID *id);
- int CRYPTO_THREADID_cmp(const CRYPTO_THREADID *a,
-                         const CRYPTO_THREADID *b);
- void CRYPTO_THREADID_cpy(CRYPTO_THREADID *dest,
-                          const CRYPTO_THREADID *src);
- unsigned long CRYPTO_THREADID_hash(const CRYPTO_THREADID *id);
-
- 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)(const 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,OPENSSL_FILE,OPENSSL_LINE)
- #define CRYPTO_w_unlock(type)	\
-	CRYPTO_lock(CRYPTO_UNLOCK|CRYPTO_WRITE,type,OPENSSL_FILE,OPENSSL_LINE)
- #define CRYPTO_r_lock(type)	\
-	CRYPTO_lock(CRYPTO_LOCK|CRYPTO_READ,type,OPENSSL_FILE,OPENSSL_LINE)
- #define CRYPTO_r_unlock(type)	\
-	CRYPTO_lock(CRYPTO_UNLOCK|CRYPTO_READ,type,OPENSSL_FILE,OPENSSL_LINE)
- #define CRYPTO_add(addr,amount,type)	\
-	CRYPTO_add_lock(addr,amount,type,OPENSSL_FILE,OPENSSL_LINE)
+ CRYPTO_RWLOCK *CRYPTO_THREAD_lock_new(void);
+ int CRYPTO_THREAD_read_lock(CRYPTO_RWLOCK *lock);
+ int CRYPTO_THREAD_write_lock(CRYPTO_RWLOCK *lock);
+ int CRYPTO_THREAD_unlock(CRYPTO_RWLOCK *lock);
+ void CRYPTO_THREAD_lock_free(CRYPTO_RWLOCK *lock);
+
+ int CRYPTO_atomic_add(int *val, int amount, int *ret, CRYPTO_RWLOCK *lock);
 
 =head1 DESCRIPTION
 
-OpenSSL can safely be used in multi-threaded applications provided
-that at least two callback functions are set, locking_function and
-threadid_func.
-
-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.
-
-threadid_func(CRYPTO_THREADID *id) is needed to record the currently-executing
-thread's identifier into B<id>. The implementation of this callback should not
-fill in B<id> directly, but should use CRYPTO_THREADID_set_numeric() if thread
-IDs are numeric, or CRYPTO_THREADID_set_pointer() if they are pointer-based.
-The B<id> must be unique for the duration of the execution of the program.
-If the application does not register such a callback using
-CRYPTO_THREADID_set_callback(), then a default implementation is used - on
-Windows this uses the system's default thread identifying APIs, and on
-all other platforms it uses the address of B<errno>. The latter is satisfactory
-for thread-safety if and only if the platform has a thread-local error number
-facility.
-
-Once threadid_func() is registered, or if the built-in default implementation is
-to be used;
+OpenSSL can be safely used in multi-threaded applications provided that
+support for the underlying OS threading API is built-in. Currently, OpenSSL
+supports the pthread and Windows APIs. OpenSSL can also be built without
+any multi-threading support, for example on platforms that don't provide
+any threading support or that provide a threading API that is not yet
+supported by OpenSSL.
+
+The following multi-threading function are provided:
 
 =over 4
 
 =item *
-CRYPTO_THREADID_current() records the currently-executing thread ID into the
-given B<id> object.
+CRYPTO_THREAD_lock_new() allocates, initializes and returns a new read/write
+lock.
 
 =item *
-CRYPTO_THREADID_cmp() compares two thread IDs (returning zero for equality, ie.
-the same semantics as memcmp()).
+CRYPTO_THREAD_read_lock() locks the provided B<lock> for reading.
 
 =item *
-CRYPTO_THREADID_cpy() duplicates a thread ID value,
+CRYPTO_THREAD_write_lock() locks the provided B<lock> for writing.
 
 =item *
-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 'long'
-variables and the platform's thread IDs are pointer-based - 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.
-
-=back
-
-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
+CRYPTO_THREAD_unlock() unlocks the previously locked B<lock>.
 
 =item *
-Three additional callback function, dyn_create_function, dyn_lock_function
-and dyn_destroy_function.
+CRYPTO_THREAD_lock_frees() frees the provided B<lock>.
 
 =item *
-A structure defined with the data that each lock needs to handle.
+CRYPTO_atomic_add() atomically adds B<amount> to B<val> and returns the
+result of the operation in B<ret>. B<lock> will be locked, unless atomic
+operations are supported on the specific platform. Because of this, if a
+variable is modified by CRYPTO_atomic_add() then CRYPTO_atomic_add() must
+be the only way that the variable is modified.
 
 =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_THREAD_lock_new() returns the allocated lock, or NULL on error.
 
-CRYPTO_get_new_dynlockid() returns the index to the newly created lock.
+CRYPTO_THREAD_lock_frees() returns no value.
 
-The other functions return no values.
+The other functions return 1 on success or 0 on error.
 
 =head1 NOTES
 
@@ -185,21 +75,6 @@ You can find out if OpenSSL was configured with thread support:
    // 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
-Solaris, Irix and Win32.
-
-=head1 HISTORY
-
-B<CRYPTO_THREADID> and associated functions were introduced in OpenSSL 1.0.0
-to replace (actually, deprecate) the previous CRYPTO_set_id_callback(),
-CRYPTO_get_id_callback(), and CRYPTO_thread_id() functions which assumed
-thread IDs to always be represented by 'unsigned long'.
-
 =head1 SEE ALSO
 
 L<crypto(3)>