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This is the first of two commits (didn't want to dump them all into the

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same one). However, the first will temporarily break things until the
second comes through. :-)

The safestack.h handling was mapping compare callbacks that externally
are of the type (int (*)(type **,type **)) into the underlying callback
type used by stack.[ch], which is (int (*)(void *,void *)). After some
degree of digging, it appears that the callback type in the underlying
stack code should use double pointers too - when the compare operations
are invoked (from sk_find and sk_sort), they are being used by bsearch
and qsort to compare two pointers to pointers. This change corrects the
prototyping (by only casting to the (void*,void*) form at the moment
it is needed by bsearch and qsort) and makes the mapping in safestack.h
more transparent. It also changes from "void*" to "char*" to stay in
keeping with stack.[ch]'s assumed base type of "char".

Also - the "const" situation was that safestack.h was throwing away
"const"s, and to compound the problem - a close examination of stack.c
showed that (const char **) is not really achieving what it is supposed
to when the callback is being invoked, what is needed is
(const char * const *). So the underlying stack.[ch] and the mapping
macros in safestack.h have all been altered to correct this.

What will follow are the vast quantities of "const" corrections required
in stack-dependant code that was being let "slip" through when
safestack.h was discarding "const"s. These now all come up as compiler
warnings.
This commit is contained in:
Geoff Thorpe
2000-06-01 02:15:40 +00:00
parent f3e9b338e0
commit 7bb7043580
3 changed files with 45 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

29
crypto/stack/stack.c
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@@ -76,9 +76,10 @@ const char *STACK_version="Stack" OPENSSL_VERSION_PTEXT;
#include <errno.h>
int (*sk_set_cmp_func(STACK *sk, int (*c)(const void *,const void *)))(const void *, const void *)
int (*sk_set_cmp_func(STACK *sk, int (*c)(const char * const *,const char * const *)))
(const char * const *, const char * const *)
{
int (*old)(const void *,const void *)=sk->comp;
int (*old)(const char * const *,const char * const *)=sk->comp;
if (sk->comp != c)
sk->sorted=0;
@@ -108,7 +109,7 @@ err:
return(NULL);
}
STACK *sk_new(int (*c)(const void *, const void *))
STACK *sk_new(int (*c)(const char * const *, const char * const *))
{
STACK *ret;
int i;
@@ -218,13 +219,24 @@ int sk_find(STACK *st, char *data)
}
sk_sort(st);
if (data == NULL) return(-1);
comp_func=st->comp;
/* This (and the "qsort" below) are the two places in OpenSSL
* where we need to convert from our standard (type **,type **)
* compare callback type to the (void *,void *) type required by
* bsearch. However, the "data" it is being called(back) with are
* not (type *) pointers, but the *pointers* to (type *) pointers,
* so we get our extra level of pointer dereferencing that way. */
comp_func=(int (*)(const void *,const void *))(st->comp);
r=(char **)bsearch(&data,(char *)st->data,
st->num,sizeof(char *), comp_func);
if (r == NULL) return(-1);
i=(int)(r-st->data);
for ( ; i>0; i--)
if ((*st->comp)(&(st->data[i-1]),&data) < 0)
/* This needs a cast because the type being pointed to from
* the "&" expressions are (char *) rather than (const char *).
* For an explanation, read:
* http://www.eskimo.com/~scs/C-faq/q11.10.html :-) */
if ((*st->comp)((const char * const *)&(st->data[i-1]),
(const char * const *)&data) < 0)
break;
return(i);
}
@@ -303,7 +315,12 @@ void sk_sort(STACK *st)
{
int (*comp_func)(const void *,const void *);
comp_func=st->comp;
/* same comment as in sk_find ... previously st->comp was declared
* as a (void*,void*) callback type, but this made the population
* of the callback pointer illogical - our callbacks compare
* type** with type**, so we leave the casting until absolutely
* necessary (ie. "now"). */
comp_func=(int (*)(const void *,const void *))(st->comp);
qsort(st->data,st->num,sizeof(char *), comp_func);
st->sorted=1;
}