Commit 94683b7a authored by Pauli's avatar Pauli
Browse files

Add a CRYPTO_atomic_read call which allows an int variable to be read 


in an atomic fashion.

Reviewed-by: default avatarRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4414)
parent 338ead0f

crypto/threads_none.c

+6 −0
Original line number Diff line number Diff line
@@ -125,6 +125,12 @@ int CRYPTO_atomic_add(int *val, int amount, int *ret, CRYPTO_RWLOCK *lock) 
    return 1;

}



int CRYPTO_atomic_read(int *val, int *ret, CRYPTO_RWLOCK *lock)

{

    *ret  = *val;

    return 1;

}



int openssl_init_fork_handlers(void)

{

    return 0;

crypto/threads_pthread.c

+19 −0
Original line number Diff line number Diff line
@@ -169,6 +169,25 @@ int CRYPTO_atomic_add(int *val, int amount, int *ret, CRYPTO_RWLOCK *lock) 
    return 1;

}



int CRYPTO_atomic_read(int *val, int *ret, CRYPTO_RWLOCK *lock)

{

# if defined(__GNUC__) && defined(__ATOMIC_ACQUIRE)

    if (__atomic_is_lock_free(sizeof(*val), val)) {

        __atomic_load(val, ret, __ATOMIC_ACQUIRE);

        return 1;

    }

# endif

    if (!CRYPTO_THREAD_write_lock(lock))

        return 0;



    *ret  = *val;



    if (!CRYPTO_THREAD_unlock(lock))

        return 0;



    return 1;

}



# ifdef OPENSSL_SYS_UNIX

static pthread_once_t fork_once_control = PTHREAD_ONCE_INIT;

crypto/threads_win.c

+6 −0
Original line number Diff line number Diff line
@@ -133,6 +133,12 @@ int CRYPTO_atomic_add(int *val, int amount, int *ret, CRYPTO_RWLOCK *lock) 
    return 1;

}



int CRYPTO_atomic_read(int *val, int *ret, CRYPTO_RWLOCK *lock)

{

    InterlockedCompareExchange(val, 0, 0);

    return 1;

}



int openssl_init_fork_handlers(void)

{

    return 0;

doc/man3/CRYPTO_THREAD_run_once.pod

+9 −1
Original line number Diff line number Diff line
@@ -4,7 +4,8 @@ 


CRYPTO_THREAD_run_once,

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

CRYPTO_THREAD_unlock, CRYPTO_THREAD_lock_free, CRYPTO_atomic_add,

CRYPTO_atomic_read - OpenSSL thread support



=head1 SYNOPSIS
@@ -20,6 +21,7 @@ CRYPTO_THREAD_unlock, CRYPTO_THREAD_lock_free, CRYPTO_atomic_add - OpenSSL threa 
 void CRYPTO_THREAD_lock_free(CRYPTO_RWLOCK *lock);



 int CRYPTO_atomic_add(int *val, int amount, int *ret, CRYPTO_RWLOCK *lock);

 int CRYPTO_atomic_read(int *val, int *ret, CRYPTO_RWLOCK *lock);



=head1 DESCRIPTION
@@ -74,6 +76,12 @@ 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.



=item *



CRYPTO_atomic_read() atomically reads 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.



=back



=head1 RETURN VALUES

include/openssl/crypto.h

+1 −0
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ 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);

int CRYPTO_atomic_read(int *val, int *ret, CRYPTO_RWLOCK *lock);



/*

 * The following can be used to detect memory leaks in the library. If