/* Run signals handlers on the stack specified by SS (if not NULL).
If OSS is not NULL, it is filled in with the old signal stack status. */
int
sigstack (struct sigstack *ss, struct sigstack *oss)
{
struct sigaltstack as, oas;
as.ss_sp = ss->ss_sp;
as.ss_size = 0;
as.ss_flags = 0;
if (__sigaltstack (&as, &oas) < 0)
return -1;
if (oss != NULL)
{
oss->ss_sp = oas.ss_sp;
oss->ss_onstack = oas.ss_flags & SS_ONSTACK;
}
return 0;
}
int
sigstack (struct sigstack *ss, struct sigstack *oss)
{
stack_t sas;
stack_t *sasp = NULL;
stack_t osas;
stack_t *osasp = oss == NULL ? NULL : &osas;
int result;
if (ss != NULL)
{
/* We have to convert the information. */
sas.ss_sp = ss->ss_sp;
sas.ss_flags = ss->ss_onstack ? SS_ONSTACK : 0;
/* For the size of the stack we have no value we can pass to the
kernel. This is why this function should not be used. We simply
assume that all the memory down to address zero (in case the stack
grows down) is available. */
sas.ss_size = ss->ss_sp - NULL;
sasp = &sas;
}
/* Call the kernel. */
result = __sigaltstack (sasp, osasp);
/* Convert the result, if wanted and possible. */
if (result == 0 && oss != NULL)
{
oss->ss_sp = osas.ss_sp;
oss->ss_onstack = (osas.ss_flags & SS_ONSTACK) != 0;
}
return result;
}
