Le 04/02/2020 à 00:15, Taylor Simpson a écrit :
>
>
>> -----Original Message-----
>> From: Laurent Vivier <laur...@vivier.eu>
>> Sent: Saturday, February 1, 2020 6:28 AM
>> To: qemu-devel@nongnu.org
>> Cc: Josh Kunz <j...@google.com>; milos.stojano...@rt-rk.com; Matus Kysel
>> <mky...@tachyum.com>; Aleksandar Markovic <aleksandar.markovic@rt-
>> rk.com>; Marlies Ruck <marlies.r...@gmail.com>; Laurent Vivier
>> <laur...@vivier.eu>; Peter Maydell <peter.mayd...@linaro.org>; Taylor
>> Simpson <tsimp...@quicinc.com>; Riku Voipio <riku.voi...@iki.fi>
>> Subject: [PATCH 4/4] linux-user: fix use of SIGRTMIN
>>
>> Some RT signals can be in use by glibc,
>> it's why SIGRTMIN (34) is generally greater than __SIGRTMIN (32).
>>
>> So SIGRTMIN cannot be mapped to TARGET_SIGRTMIN.
>>
>> Instead of swapping only SIGRTMIN and SIGRTMAX, map all the range
>> [TARGET_SIGRTMIN ... TARGET_SIGRTMAX - X] to
>> [__SIGRTMIN + X ... SIGRTMAX ]
>> (SIGRTMIN is __SIGRTMIN + X).
>>
>> Signed-off-by: Laurent Vivier <laur...@vivier.eu>
>> ---
>> linux-user/signal.c | 34 ++++++++++++++++++++++++++++------
>> linux-user/trace-events | 3 +++
>> 2 files changed, 31 insertions(+), 6 deletions(-)
>>
>> diff --git a/linux-user/signal.c b/linux-user/signal.c index
>> 3491f0a7ecb1..c4abacde49a0 100644
>> --- a/linux-user/signal.c
>> +++ b/linux-user/signal.c
>> @@ -501,15 +501,20 @@ static void signal_table_init(void)
>> int i, j;
>>
>> /*
>> - * Nasty hack: Reverse SIGRTMIN and SIGRTMAX to avoid overlap with
>> - * host libpthread signals. This assumes no one actually uses SIGRTMAX
>> :-/
>> - * To fix this properly we need to do manual signal delivery multiplexed
>> - * over a single host signal.
>> + * some RT signals can be in use by glibc,
>> + * it's why SIGRTMIN (34) is generally greater than __SIGRTMIN (32)
>> */
>> - host_to_target_signal_table[__SIGRTMIN] = __SIGRTMAX;
>> - host_to_target_signal_table[__SIGRTMAX] = __SIGRTMIN;
>> + for (i = SIGRTMIN; i <= SIGRTMAX; i++) {
>> + j = i - SIGRTMIN + TARGET_SIGRTMIN;
>> + if (j <= TARGET_NSIG) {
>> + host_to_target_signal_table[i] = j;
>> + }
>> + }
>>
>> /* generate signal conversion tables */
>> + for (i = 1; i <= TARGET_NSIG; i++) {
>> + target_to_host_signal_table[i] = _NSIG; /* poison */
>> + }
>> for (i = 1; i < _NSIG; i++) {
>> if (host_to_target_signal_table[i] == 0) {
>> host_to_target_signal_table[i] = i; @@ -519,6 +524,15 @@ static
>> void
>> signal_table_init(void)
>> target_to_host_signal_table[j] = i;
>> }
>> }
>> +
>> + if (TRACE_SIGNAL_TABLE_INIT_BACKEND_DSTATE()) {
>> + for (i = 1, j = 0; i <= TARGET_NSIG; i++) {
>> + if (target_to_host_signal_table[i] == _NSIG) {
>> + j++;
>> + }
>> + }
>> + trace_signal_table_init(j);
>
> It looks like j will have a count of the number of poison entries, but the
> message in trace_signal_table_init is "missing signal number". Is that what
> you intend?
Yes, poison entries are the entries that cannot be used for the guest.
Perhaps it would be more correct as "Number of missing signals:"?
>
>> + }
>> }
>>
>> void signal_init(void)
>> @@ -817,6 +831,8 @@ int do_sigaction(int sig, const struct target_sigaction
>> *act,
>> int host_sig;
>> int ret = 0;
>>
>> + trace_signal_do_sigaction_guest(sig, TARGET_NSIG);
>
> Shouldn't this be _NSIG, not TARGET_NSIG?
No: do_sigaction() takes a number from the guest, so "sig" is a target
signal number, and this trace displays also the maximum value for the
target.
Thanks,
Laurent
