1ec6848bcSbeckThe goals: 2ec6848bcSbeck1) calls from inside libcrypto to other libcrypto functions should 3ec6848bcSbeck be via identifiers that are of hidden visibility and -- to avoid 4ec6848bcSbeck confusion or conflicts -- are in the reserved namespace. By 5ec6848bcSbeck doing this these calls are protected from being overridden by 6ec6848bcSbeck applications and on many platforms can avoid creation or use of 7ec6848bcSbeck GOT or PLT entries. I've chosen a prefix of "_lcry_" for this. 8ec6848bcSbeck Note that these symbols aren't in the dynamic symbol table of the 9ec6848bcSbeck libcrypto.so shared library...but they are visible in the static 10ec6848bcSbeck library. 11ec6848bcSbeck 12ec6848bcSbeck2) calls from libssl to symbols in libcrypto should be via identifiers 13ec6848bcSbeck which won't be accidentally overridden by the application, libc, 14ec6848bcSbeck other random crypto libraries that are pulled in, etc. I've 15ec6848bcSbeck chosen a prefix of "_libre_" for this. 16ec6848bcSbeck 17ec6848bcSbeckThese will not be declared directly; instead, the gcc "asm labels" 18ec6848bcSbeckextension will be used rename the function. In order to actually 19ec6848bcSbeckset up the desired asm labels, we use these in the internal .h 20ec6848bcSbeckfiles: 21ec6848bcSbeck 22ec6848bcSbeck LCRYPTO_USED(x) Symbols used both internally and externally 23ec6848bcSbeck In builds of libcrypto, this makes gcc convert use of x to 24ec6848bcSbeck use _libre_x instead. In other builds that use these headers, 25ec6848bcSbeck it makes gcc convert use of x to use _libre_x instead. Use 26ec6848bcSbeck LCRYPTO_ALIAS(x) to create the external aliases. 27ec6848bcSbeck ex: LCRYPTO_USED(SSL_get_verify_mode) 28ec6848bcSbeck 29ec6848bcSbeck LCRYPTO_UNUSED(x) Symbols that are not used internally or by libssl 30ec6848bcSbeck No renaming is done. In builds of libcrypto, the symbol 31ec6848bcSbeck is marked as deprecated to detect unintentional use of such 32*303eb450Stobhe a symbol, so that it can be marked as used going forward. 33ec6848bcSbeck ex: LCRYPTO_UNUSED(SSL_CIPHER_get_name) 34ec6848bcSbeck 35ec6848bcSbeckFinally, to create the expected aliases, we use these in the .c files 36ec6848bcSbeckwhere the definitions are: 37ec6848bcSbeck LCRYPTO_ALIAS(x) 38ec6848bcSbeck This defines both x and _libre_x as strong aliases for _lcry_x. 39ec6848bcSbeck Match uses of this with uses of LCRYPTO_USED() 40ec6848bcSbeck ex: LCRYPTO_ALIAS(SSL_get_verify_mode) 41