Hi there,
Having just downloaded GCC 4.2.0 and discovered that it can't build
OpenSSL (not even in the snapshots AFAICT), I'd like to offer a possible
solution.
The earlier thread on openssl-dev explains that OpenSSL chooses to cast
the function pointers, not the parameters, to achieve type-safety; i.e.
to ensure that errors occur if the wrong types are passed to the
XYZ_of() functions.
So how about using expressions of the form
(void*)(1 ? x : ((T*)NULL))
instead? That way, if x isn't of the right type, GCC will warn because
the ?: gets different types in the two branches. Meanwhile the function
itself is getting called with the correct types, and while OpenSSL is
still "deceiving" the type system, it's doing so only via function
pointers (so there's no way that the compiler, examining any one
translation unit, can "tell" that deception is being attempted). And the
compiler should easily spot that the condition ("1") is always true, and
so generate no extra code compared to the direct, non-typesafe call.
Attached is a patch against SNAP-20070516 which lets all the tests pass
under GCC 4.2.0 (on ia32 and amd64).
Peter
--- crypto/asn1/asn1.h~ 2007-04-14 19:00:19.000000000 +0100
+++ crypto/asn1/asn1.h 2007-05-16 14:48:27.000000000 +0100
@@ -329,6 +329,17 @@ typedef struct ASN1_VALUE_st ASN1_VALUE;
#define I2D_OF(type) int (*)(type *,unsigned char **)
#define I2D_OF_const(type) int (*)(const type *,unsigned char **)
+#define CHECKED_D2I_OF(type, d2i) \
+ ((d2i_of_void*) (1 ? d2i : ((D2I_OF(type))0)))
+#define CHECKED_I2D_OF(type, i2d) \
+ ((i2d_of_void*) (1 ? i2d : ((I2D_OF(type))0)))
+#define CHECKED_NEW_OF(type, xnew) \
+ ((void *(*)(void)) (1 ? xnew : ((type *(*)(void))0)))
+#define CHECKED_PTR_OF(type, p) \
+ ((void*) (1 ? p : (type*)0))
+#define CHECKED_PPTR_OF(type, p) \
+ ((void**) (1 ? p : (type**)0))
+
#define TYPEDEF_D2I_OF(type) typedef type *d2i_of_##type(type **,const unsigned char **,long)
#define TYPEDEF_I2D_OF(type) typedef int i2d_of_##type(type *,unsigned char **)
#define TYPEDEF_D2I2D_OF(type) TYPEDEF_D2I_OF(type); TYPEDEF_I2D_OF(type)
@@ -914,23 +925,41 @@ int ASN1_object_size(int constructed, in
/* Used to implement other functions */
void *ASN1_dup(i2d_of_void *i2d, d2i_of_void *d2i, char *x);
+
#define ASN1_dup_of(type,i2d,d2i,x) \
- ((type *(*)(I2D_OF(type),D2I_OF(type),type *))openssl_fcast(ASN1_dup))(i2d,d2i,x)
+ ((type*)ASN1_dup(CHECKED_I2D_OF(type, i2d), \
+ CHECKED_D2I_OF(type, d2i), \
+ CHECKED_PTR_OF(type, x)))
+
#define ASN1_dup_of_const(type,i2d,d2i,x) \
- ((type *(*)(I2D_OF_const(type),D2I_OF(type),type *))openssl_fcast(ASN1_dup))(i2d,d2i,x)
+ ((type*)ASN1_dup(CHECKED_I2D_OF(const type, i2d), \
+ CHECKED_D2I_OF(type, d2i), \
+ CHECKED_PTR_OF(const type, x)))
void *ASN1_item_dup(const ASN1_ITEM *it, void *x);
#ifndef OPENSSL_NO_FP_API
void *ASN1_d2i_fp(void *(*xnew)(void), d2i_of_void *d2i, FILE *in, void **x);
+
#define ASN1_d2i_fp_of(type,xnew,d2i,in,x) \
- ((type *(*)(type *(*)(void),D2I_OF(type),FILE *,type **))openssl_fcast(ASN1_d2i_fp))(xnew,d2i,in,x)
+ ((type*)ASN1_d2i_fp(CHECKED_NEW_OF(type, xnew), \
+ CHECKED_D2I_OF(type, d2i), \
+ in, \
+ CHECKED_PPTR_OF(type, x)))
+
void *ASN1_item_d2i_fp(const ASN1_ITEM *it, FILE *in, void *x);
int ASN1_i2d_fp(i2d_of_void *i2d,FILE *out,void *x);
+
#define ASN1_i2d_fp_of(type,i2d,out,x) \
- ((int (*)(I2D_OF(type),FILE *,type *))openssl_fcast(ASN1_i2d_fp))(i2d,out,x)
+ (ASN1_i2d_fp(CHECKED_I2D_OF(type, i2d), \
+ out, \
+ CHECKED_PTR_OF(type, x)))
+
#define ASN1_i2d_fp_of_const(type,i2d,out,x) \
- ((int (*)(I2D_OF_const(type),FILE *,type *))openssl_fcast(ASN1_i2d_fp))(i2d,out,x)
+ (ASN1_i2d_fp(CHECKED_I2D_OF(const type, i2d), \
+ out, \
+ CHECKED_PTR_OF(const type, x)))
+
int ASN1_item_i2d_fp(const ASN1_ITEM *it, FILE *out, void *x);
int ASN1_STRING_print_ex_fp(FILE *fp, ASN1_STRING *str, unsigned long flags);
#endif
@@ -939,14 +968,26 @@ int ASN1_STRING_to_UTF8(unsigned char **
#ifndef OPENSSL_NO_BIO
void *ASN1_d2i_bio(void *(*xnew)(void), d2i_of_void *d2i, BIO *in, void **x);
+
#define ASN1_d2i_bio_of(type,xnew,d2i,in,x) \
- ((type *(*)(type *(*)(void),D2I_OF(type),BIO *,type **))openssl_fcast(ASN1_d2i_bio))(xnew,d2i,in,x)
+ ((type*)ASN1_d2i_bio( CHECKED_NEW_OF(type, xnew), \
+ CHECKED_D2I_OF(type, d2i), \
+ in, \
+ CHECKED_PPTR_OF(type, x)))
+
void *ASN1_item_d2i_bio(const ASN1_ITEM *it, BIO *in, void *x);
int ASN1_i2d_bio(i2d_of_void *i2d,BIO *out, unsigned char *x);
+
#define ASN1_i2d_bio_of(type,i2d,out,x) \
- ((int (*)(I2D_OF(type),BIO *,type *))openssl_fcast(ASN1_i2d_bio))(i2d,out,x)
+ (ASN1_i2d_bio(CHECKED_I2D_OF(type, i2d), \
+ out, \
+ CHECKED_PTR_OF(type, x)))
+
#define ASN1_i2d_bio_of_const(type,i2d,out,x) \
- ((int (*)(I2D_OF_const(type),BIO *,const type *))openssl_fcast(ASN1_i2d_bio))(i2d,out,x)
+ (ASN1_i2d_bio(CHECKED_I2D_OF(const type, i2d), \
+ out, \
+ CHECKED_PTR_OF(const type, x)))
+
int ASN1_item_i2d_bio(const ASN1_ITEM *it, BIO *out, void *x);
int ASN1_UTCTIME_print(BIO *fp, const ASN1_UTCTIME *a);
int ASN1_GENERALIZEDTIME_print(BIO *fp, const ASN1_GENERALIZEDTIME *a);
@@ -983,8 +1024,12 @@ void *ASN1_unpack_string(ASN1_STRING *oc
void *ASN1_item_unpack(ASN1_STRING *oct, const ASN1_ITEM *it);
ASN1_STRING *ASN1_pack_string(void *obj, i2d_of_void *i2d,
ASN1_OCTET_STRING **oct);
+
#define ASN1_pack_string_of(type,obj,i2d,oct) \
- ((ASN1_STRING *(*)(type *,I2D_OF(type),ASN1_OCTET_STRING **))openssl_fcast(ASN1_pack_string))(obj,i2d,oct)
+ (ASN1_pack_string(CHECKED_PTR_OF(type, obj), \
+ CHECKED_I2D_OF(type, i2d), \
+ oct))
+
ASN1_STRING *ASN1_item_pack(void *obj, const ASN1_ITEM *it, ASN1_OCTET_STRING **oct);
void ASN1_STRING_set_default_mask(unsigned long mask);
--- crypto/pem/pem.h~ 2007-04-05 18:00:52.000000000 +0100
+++ crypto/pem/pem.h 2007-05-16 14:48:42.000000000 +0100
@@ -221,19 +221,28 @@ typedef struct pem_ctx_st
#define IMPLEMENT_PEM_read_fp(name, type, str, asn1) \
type *PEM_read_##name(FILE *fp, type **x, pem_password_cb *cb, void *u)\
{ \
-return(((type *(*)(D2I_OF(type),char *,FILE *,type **,pem_password_cb *,void *))openssl_fcast(PEM_ASN1_read))(d2i_##asn1, str,fp,x,cb,u)); \
+ return (type*)PEM_ASN1_read(CHECKED_D2I_OF(type, d2i_##asn1), \
+ str, fp, \
+ CHECKED_PPTR_OF(type, x), \
+ cb, u); \
}
#define IMPLEMENT_PEM_write_fp(name, type, str, asn1) \
int PEM_write_##name(FILE *fp, type *x) \
{ \
-return(((int (*)(I2D_OF(type),const char *,FILE *,type *, const EVP_CIPHER *,unsigned char *,int, pem_password_cb *,void *))openssl_fcast(PEM_ASN1_write))(i2d_##asn1,str,fp,x,NULL,NULL,0,NULL,NULL)); \
+ return PEM_ASN1_write(CHECKED_I2D_OF(type, i2d_##asn1), \
+ str, fp, \
+ CHECKED_PTR_OF(type, x), \
+ NULL, NULL, 0, NULL, NULL); \
}
#define IMPLEMENT_PEM_write_fp_const(name, type, str, asn1) \
int PEM_write_##name(FILE *fp, const type *x) \
{ \
-return(((int (*)(I2D_OF_const(type),const char *,FILE *, const type *, const EVP_CIPHER *,unsigned char *,int, pem_password_cb *,void *))openssl_fcast(PEM_ASN1_write))(i2d_##asn1,str,fp,x,NULL,NULL,0,NULL,NULL)); \
+ return PEM_ASN1_write(CHECKED_I2D_OF(const type, i2d_##asn1), \
+ str, fp, \
+ CHECKED_PTR_OF(const type, x), \
+ NULL, NULL, 0, NULL, NULL); \
}
#define IMPLEMENT_PEM_write_cb_fp(name, type, str, asn1) \
@@ -241,7 +250,10 @@ int PEM_write_##name(FILE *fp, type *x,
unsigned char *kstr, int klen, pem_password_cb *cb, \
void *u) \
{ \
- return(((int (*)(I2D_OF(type),const char *,FILE *,type *, const EVP_CIPHER *,unsigned char *,int, pem_password_cb *,void *))openssl_fcast(PEM_ASN1_write))(i2d_##asn1,str,fp,x,enc,kstr,klen,cb,u)); \
+ return PEM_ASN1_write(CHECKED_I2D_OF(type, i2d_##asn1), \
+ str, fp, \
+ CHECKED_PTR_OF(type, x), \
+ enc, kstr, klen, cb, u); \
}
#define IMPLEMENT_PEM_write_cb_fp_const(name, type, str, asn1) \
@@ -249,7 +261,10 @@ int PEM_write_##name(FILE *fp, type *x,
unsigned char *kstr, int klen, pem_password_cb *cb, \
void *u) \
{ \
- return(((int (*)(I2D_OF_const(type),const char *,FILE *,type *, const EVP_CIPHER *,unsigned char *,int, pem_password_cb *,void *))openssl_fcast(PEM_ASN1_write))(i2d_##asn1,str,fp,x,enc,kstr,klen,cb,u)); \
+ return PEM_ASN1_write(CHECKED_I2D_OF(const type, i2d_##asn1), \
+ str, fp, \
+ CHECKED_PTR_OF(const type, x), \
+ enc, kstr, klen, cb, u); \
}
#endif
@@ -257,33 +272,48 @@ int PEM_write_##name(FILE *fp, type *x,
#define IMPLEMENT_PEM_read_bio(name, type, str, asn1) \
type *PEM_read_bio_##name(BIO *bp, type **x, pem_password_cb *cb, void *u)\
{ \
-return(((type *(*)(D2I_OF(type),const char *,BIO *,type **,pem_password_cb *,void *))openssl_fcast(PEM_ASN1_read_bio))(d2i_##asn1, str,bp,x,cb,u)); \
+ return (type*)PEM_ASN1_read_bio(CHECKED_D2I_OF(type, d2i_##asn1), \
+ str, bp, \
+ CHECKED_PPTR_OF(type, x), \
+ cb, u); \
}
#define IMPLEMENT_PEM_write_bio(name, type, str, asn1) \
int PEM_write_bio_##name(BIO *bp, type *x) \
{ \
-return(((int (*)(I2D_OF(type),const char *,BIO *,type *, const EVP_CIPHER *,unsigned char *,int, pem_password_cb *,void *))openssl_fcast(PEM_ASN1_write_bio))(i2d_##asn1,str,bp,x,NULL,NULL,0,NULL,NULL)); \
+ return PEM_ASN1_write_bio(CHECKED_I2D_OF(type, i2d_##asn1), \
+ str, bp, \
+ CHECKED_PTR_OF(type, x), \
+ NULL, NULL, 0, NULL, NULL); \
}
#define IMPLEMENT_PEM_write_bio_const(name, type, str, asn1) \
int PEM_write_bio_##name(BIO *bp, const type *x) \
{ \
-return(((int (*)(I2D_OF_const(type),const char *,BIO *,const type *, const EVP_CIPHER *,unsigned char *,int, pem_password_cb *,void *))openssl_fcast(PEM_ASN1_write_bio))(i2d_##asn1,str,bp,x,NULL,NULL,0,NULL,NULL)); \
+ return PEM_ASN1_write_bio(CHECKED_I2D_OF(const type, i2d_##asn1), \
+ str, bp, \
+ CHECKED_PTR_OF(const type, x), \
+ NULL, NULL, 0, NULL, NULL); \
}
#define IMPLEMENT_PEM_write_cb_bio(name, type, str, asn1) \
int PEM_write_bio_##name(BIO *bp, type *x, const EVP_CIPHER *enc, \
unsigned char *kstr, int klen, pem_password_cb *cb, void *u) \
{ \
- return(((int (*)(I2D_OF(type),const char *,BIO *,type *,const EVP_CIPHER *,unsigned char *,int,pem_password_cb *,void *))openssl_fcast(PEM_ASN1_write_bio))(i2d_##asn1,str,bp,x,enc,kstr,klen,cb,u)); \
+ return PEM_ASN1_write_bio(CHECKED_I2D_OF(type, i2d_##asn1), \
+ str, bp, \
+ CHECKED_PTR_OF(type, x), \
+ enc, kstr, klen, cb, u); \
}
#define IMPLEMENT_PEM_write_cb_bio_const(name, type, str, asn1) \
int PEM_write_bio_##name(BIO *bp, type *x, const EVP_CIPHER *enc, \
unsigned char *kstr, int klen, pem_password_cb *cb, void *u) \
{ \
- return(((int (*)(I2D_OF_const(type),const char *,BIO *,type *,const EVP_CIPHER *,unsigned char *,int,pem_password_cb *,void *))openssl_fcast(PEM_ASN1_write_bio))(i2d_##asn1,str,bp,x,enc,kstr,klen,cb,u)); \
+ return PEM_ASN1_write_bio(CHECKED_I2D_OF(const type, i2d_##asn1), \
+ str, bp, \
+ CHECKED_PTR_OF(const type, x), \
+ enc, kstr, klen, cb, u); \
}
#define IMPLEMENT_PEM_write(name, type, str, asn1) \
@@ -414,13 +444,22 @@ int PEM_bytes_read_bio(unsigned char **p
pem_password_cb *cb, void *u);
void * PEM_ASN1_read_bio(d2i_of_void *d2i, const char *name, BIO *bp,
void **x, pem_password_cb *cb, void *u);
+
#define PEM_ASN1_read_bio_of(type,d2i,name,bp,x,cb,u) \
-((type *(*)(D2I_OF(type),const char *,BIO *,type **,pem_password_cb *,void *))openssl_fcast(PEM_ASN1_read_bio))(d2i,name,bp,x,cb,u)
+ ((type*)PEM_ASN1_read_bio(CHECKED_D2I_OF(type, d2i), \
+ name, bp, \
+ CHECKED_PPTR_OF(type, x), \
+ cb, u))
+
int PEM_ASN1_write_bio(i2d_of_void *i2d,const char *name,BIO *bp,char *x,
const EVP_CIPHER *enc,unsigned char *kstr,int klen,
pem_password_cb *cb, void *u);
+
#define PEM_ASN1_write_bio_of(type,i2d,name,bp,x,enc,kstr,klen,cb,u) \
- ((int (*)(I2D_OF(type),const char *,BIO *,type *, const EVP_CIPHER *,unsigned char *,int, pem_password_cb *,void *))openssl_fcast(PEM_ASN1_write_bio))(i2d,name,bp,x,enc,kstr,klen,cb,u)
+ (PEM_ASN1_write_bio(CHECKED_I2D_OF(type, i2d), \
+ name, bp, \
+ CHECKED_PTR_OF(type, x), \
+ enc, kstr, klen, cb, u))
STACK_OF(X509_INFO) * PEM_X509_INFO_read_bio(BIO *bp, STACK_OF(X509_INFO) *sk, pem_password_cb *cb, void *u);
int PEM_X509_INFO_write_bio(BIO *bp,X509_INFO *xi, EVP_CIPHER *enc,
