Commit fa9bb620 authored by Richard Levitte's avatar Richard Levitte
Browse files

Update the documentation on heap allocators / deallocators



Reviewed-by: default avatarRich Salz <rsalz@openssl.org>
parent 05c7b163
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+17 −10
Original line number Diff line number Diff line
@@ -34,20 +34,20 @@ CRYPTO_mem_leaks, CRYPTO_mem_leaks_fp - Memory allocation functions
 void *CRYPTO_malloc(size_t num, const char *file, int line)
 void *CRYPTO_zalloc(size_t num, const char *file, int line)
 void *CRYPTO_realloc(void *p, size_t num, const char *file, int line)
 void CRYPTO_free(void *str)
 void CRYPTO_free(void *str, const char *, int)
 char *CRYPTO_strdup(const char *p, const char *file, int line)
 char *CRYPTO_strndup(const char *p, size_t num, const char *file, int line)
 void *CRYPTO_clear_realloc(void *p, size_t old_len, size_t num, const char *file, int line)
 void CRYPTO_clear_free(void *str, size_t num)
 void CRYPTO_clear_free(void *str, size_t num, const char *, int)

 void CRYPTO_get_mem_functions(
         void *(**m)(size_t, const char *, int),
         void *(**r)(void *, size_t, const char *, int),
         void (**f)(void *))
         void (**f)(void *, const char *, int))
 int CRYPTO_set_mem_functions(
         void *(*m)(size_t, const char *, int),
         void *(*r)(void *, size_t, const char *, int),
         void (*f)(void *))
         void (*f)(void *, const char *, int))

 int CRYPTO_set_mem_debug(int onoff)

@@ -96,12 +96,11 @@ OPENSSL_strlcat() and OPENSSL_strnlen() are equivalents of the common C
library functions and are provided for portability.

If no allocations have been done, it is possible to "swap out" the default
implementations and replace them with alternate versions, or wrappers that
do some additional housekeeping and then defer to the OpenSSL implementation.
The CRYPTO_get_mem_functions() function fills in the function pointers for
with the current functions (normally, and by default,
CRYPTO_malloc(), CRYPTO_realloc(), and CRYPTO_free()).
The CRYPTO_set_mem_functions() specifies a different set of functions.
implementations for OPENSSL_malloc(), OPENSSL_realloc and OPENSSL_free()
and replace them with alternate versions (hooks).
CRYPTO_get_mem_functions() function fills in the given arguments with the
function pointers for the current implementations.
With CRYPTO_set_mem_functions(), you can specify a different set of functions.
If any of B<m>, B<r>, or B<f> are NULL, then the function is not changed.

The default implementation can include some debugging capability (if enabled
@@ -160,4 +159,12 @@ CRYPTO_mem_ctrl() returns the previous value of the mode.
OPENSSL_mem_debug_push() and OPENSSL_mem_debug_pop()
return 1 on success or 0 on failure.

=head1 NOTES

While it's permitted to swap out only a few and not all the functions
with CRYPTO_set_mem_functions(), it's recommended to swap them all out
at once.  I<This applies specially if OpenSSL was built with the
configuration option> C<crypto-mdebug> I<enabled.  In case, swapping out
only, say, the malloc() implementation is outright dangerous.>

=cut
+3 −2
Original line number Diff line number Diff line
@@ -25,7 +25,7 @@ CYRPTO_secure_malloc_used - secure heap storage
 void *CRYPTO_secure_zalloc(int num, const char *file, int line);

 void OPENSSL_secure_free(void* ptr);
 void CRYPTO_secure_free(void *ptr);
 void CRYPTO_secure_free(void *ptr, const char *, int);

 size_t OPENSSL_secure_actual_size(const void *ptr);
 int OPENSSL_secure_allocated(const void *ptr);
@@ -74,7 +74,8 @@ OPENSSL_secure_malloc().
If CRYPTO_secure_malloc_init() is not called, this is equivalent to
calling OPENSSL_free().
It exists for consistency with OPENSSL_secure_malloc() , and
is a macro that expands to CRYPTO_secure_free().
is a macro that expands to CRYPTO_secure_free() and adds the C<__FILE__>
and C<__LINE__> parameters..

OPENSSL_secure_allocated() tells whether or not a pointer is within
the secure heap.