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Fix sigaltstack decoder

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strace used to hang when decoding sigaltstack called with invalid
stack_t pointers because of mishandling umove() return code.

* signal.c (print_stack_t): Handle unfetchable stack_t properly.
Change return type to void.
(sys_sigaltstack): Update print_stack_t() usage.

Reported-by: kawillia@ucalgary.ca
This commit is contained in:
Дмитрий Левин 2013-02-09 02:03:04 +00:00
parent 0cf04b6595
commit 338c069e69
1 changed files with 13 additions and 15 deletions
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28
signal.c
View File

@ -1015,33 +1015,31 @@ static const struct xlat sigaltstack_flags[] = {
{ 0, NULL },
};
static int
static void
print_stack_t(struct tcb *tcp, unsigned long addr)
{
stack_t ss;
if (umove(tcp, addr, &ss) < 0)
return -1;
tprintf("{ss_sp=%#lx, ss_flags=", (unsigned long) ss.ss_sp);
printflags(sigaltstack_flags, ss.ss_flags, "SS_???");
tprintf(", ss_size=%lu}", (unsigned long) ss.ss_size);
return 0;
if (!addr) {
tprints("NULL");
} else if (umove(tcp, addr, &ss) < 0) {
tprintf("%#lx", addr);
} else {
tprintf("{ss_sp=%#lx, ss_flags=", (unsigned long) ss.ss_sp);
printflags(sigaltstack_flags, ss.ss_flags, "SS_???");
tprintf(", ss_size=%lu}", (unsigned long) ss.ss_size);
}
}
int
sys_sigaltstack(struct tcb *tcp)
{
if (entering(tcp)) {
if (tcp->u_arg[0] == 0)
tprints("NULL");
else if (print_stack_t(tcp, tcp->u_arg[0]) < 0)
return -1;
print_stack_t(tcp, tcp->u_arg[0]);
}
else {
tprints(", ");
if (tcp->u_arg[1] == 0)
tprints("NULL");
else if (print_stack_t(tcp, tcp->u_arg[1]) < 0)
return -1;
print_stack_t(tcp, tcp->u_arg[1]);
}
return 0;
}