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Untangle ifdef forest in sys_mmap64. No code changes

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After careful analysis, it looks like !LINUX and ALPHA
pass all seven parameters in registers; and in all other cases
parameters are on stack (pointed to by tcp->u_arg[0]).
In light of this, reorganize ifdefs, making them simpler,
without changing any logic.
After this, it's apparent we use tcp->u_arg[4,5,6] and possibly
[7] without checking that it's valid to do so.
So far, just add a comment about this.

* mem.c (sys_mmap64): Rewrite ifdefs in a much simpler way.
Add comments about apparent bugs.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
This commit is contained in:
Denys Vlasenko 2011-08-19 16:11:07 +02:00
parent 72a5848741
commit 31f9cb6f48
1 changed files with 9 additions and 16 deletions
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25
mem.c
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@ -334,25 +334,15 @@ sys_mmap(struct tcb *tcp)
int
sys_mmap64(struct tcb *tcp)
{
#ifdef linux
#ifdef ALPHA
long *u_arg = tcp->u_arg;
#else /* !ALPHA */
long u_arg[7];
#endif /* !ALPHA */
#else /* !linux */
long *u_arg = tcp->u_arg;
#endif /* !linux */
if (entering(tcp)) {
#ifdef linux
#ifndef ALPHA
#if !defined(LINUX) || defined(ALPHA)
long *u_arg = tcp->u_arg;
#else
long u_arg[7];
if (umoven(tcp, tcp->u_arg[0], sizeof u_arg,
(char *) u_arg) == -1)
return 0;
#endif /* ALPHA */
#endif /* linux */
#endif
/* addr */
tprintf("%#lx, ", u_arg[0]);
/* len */
@ -369,13 +359,16 @@ sys_mmap64(struct tcb *tcp)
#endif
/* fd */
tprintf(", ");
/* BUG?! should be u_arg[4] (without tcp->)? */
printfd(tcp, tcp->u_arg[4]);
/* offset */
/* BUG?! on non-ALPHA linux, offset will be not in tcp->u_arg,
* but in local u_arg, but printllval prints tcp->u_arg! */
printllval(tcp, ", %#llx", 5);
}
return RVAL_HEX;
}
#endif
#endif /* _LFS64_LARGEFILE || HAVE_LONG_LONG_OFF_T */
int