On Fri, 2025-07-11 at 07:40 +0200, Thomas Weißschuh wrote:
On 2025-07-10 12:39:50+0200, Benjamin Berg wrote:
From: Benjamin Berg benjamin.berg@intel.com
Add support for sigaction() and implement the normal sa_mask helpers.
On many architectures, linux/signal.h pulls in compatibility definitions for the old sigaction syscall instead of rt_sigaction. However, the kernel can be compiled without support for this compatibility syscall and it also results in sa_mask to be too small for realtime signals.
To work around this, the includes are handled separately for each architecture. This way either linux/signal.h or the asm-generic headers can be used to get the correct definition for the rt_sigaction syscall including sigset_t.
I checked this against my WIP alpha support and there this scheme breaks. linux/signal.h provides the old compat types but the asm-generic variant provides an incorrect SIGCHLD.
Any ideas?
I had a quick look, and I don't have a good idea really. For sparc there was at least a #define that permitted to get the correct version. But here, there is nothing.
Probably the best is to just copy in a modified version of signal.h with the correct definitions present. i.e. replace the "ifndef __KERNEL__" sections with something reasonable.
Signed-off-by: Benjamin Berg benjamin.berg@intel.com
v2:
- Use newly added macros to check signal emission order
- Add tests for sigset handling
- Restore the default handler after signal test
- make signal_check variable static
v1:
- Update architecture support (adding sh)
- Move sparc sys_rt_sigaction logic into its header
- Add sig_atomic_t
- Use new BITSET_* macros
- Move test into syscall suite
- Various other small changes
tools/include/nolibc/arch-arm.h | 7 ++ tools/include/nolibc/arch-arm64.h | 3 + tools/include/nolibc/arch-loongarch.h | 3 + tools/include/nolibc/arch-m68k.h | 10 ++ tools/include/nolibc/arch-mips.h | 3 + tools/include/nolibc/arch-powerpc.h | 8 ++ tools/include/nolibc/arch-riscv.h | 3 + tools/include/nolibc/arch-s390.h | 8 +- tools/include/nolibc/arch-sh.h | 5 + tools/include/nolibc/arch-sparc.h | 47 ++++++++ tools/include/nolibc/arch-x86.h | 13 +++ tools/include/nolibc/signal.h | 103 +++++++++++++++++ tools/include/nolibc/sys.h | 2 +- tools/include/nolibc/time.h | 3 +- tools/include/nolibc/types.h | 9 ++ tools/testing/selftests/nolibc/nolibc-test.c | 115 +++++++++++++++++++ 16 files changed, 338 insertions(+), 4 deletions(-)
(...)
diff --git a/tools/include/nolibc/signal.h b/tools/include/nolibc/signal.h index ac13e53ac31d..16b8b17496bc 100644 --- a/tools/include/nolibc/signal.h +++ b/tools/include/nolibc/signal.h @@ -14,6 +14,14 @@ #include "arch.h" #include "types.h" #include "sys.h" +#include "string.h"
Unnecessary now as memset() is not used anymore.
+/* other signal definitions are included by arch.h */
+/* The kernel headers do not provide a sig_atomic_t definition */ +#ifndef __sig_atomic_t_defined +#define __sig_atomic_t_defined 1 +typedef int sig_atomic_t; +#endif
(...)
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index d612150d2ea3..fcd44b27cd5e 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -1293,6 +1293,120 @@ int test_namespace(void) return ret; } +sig_atomic_t signal_check;
Still not static :-)
Eeks.
+static void sighandler(int signum) +{
- if (signum == SIGUSR1) {
kill(getpid(), SIGUSR2);/* The second step has not run because SIGUSR2 ismasked */
MARK_STEP_DONE(signal_check, 0);- } else {
MARK_STEP_DONE(signal_check, 1);- }
+}
+int test_signals(int test_idx) +{
- struct sigaction sa = {
.sa_flags = 0,.sa_handler = sighandler,- };
- struct sigaction sa_old = {
/* Anything other than SIG_DFL */.sa_handler = sighandler,- };
- int llen; /* line length */
- int ret = 0;
- int res;
- signal_check = 0;
+#ifdef NOLIBC
- /* Do some checks on sa_mask handling */
- sigfillset(&sa.sa_mask);
- llen = printf(" sa_mask.sig[0] (full): ");
- EXPECT_EQ(1, sa.sa_mask.sig[0],
~(__typeof__(sa.sa_mask.sig[0]))0);- llen = printf(" sa_mask.sig[%d] (full): ",
(int)_NSIG_WORDS - 1);
- EXPECT_EQ(1, sa.sa_mask.sig[_NSIG_WORDS - 1],
~(__typeof__(sa.sa_mask.sig[0]))0);- sigemptyset(&sa.sa_mask);
- llen = printf(" sa_mask.sig[0] (empty): ");
- EXPECT_EQ(1, sa.sa_mask.sig[0], 0);
- llen = printf(" sa_mask.sig[%d] (empty): ",
(int)_NSIG_WORDS - 1);
- EXPECT_EQ(1, sa.sa_mask.sig[_NSIG_WORDS - 1], 0);
- /* SIGUSR2 is always in the first word */
- sigaddset(&sa.sa_mask, SIGUSR2);
- llen = printf(" sa_mask.sig[0] (SIGUSR2 set): ");
- EXPECT_EQ(1, sa.sa_mask.sig[0], 1 << (SIGUSR2 - 1));
- llen = printf(" sa_mask.sig[0] (test SIGUSR2): ");
- EXPECT_NZ(1, sigismember(&sa.sa_mask, SIGUSR2));
- sigdelset(&sa.sa_mask, SIGUSR2);
- llen = printf(" sa_mask.sig[0] (SIGUSR2 unset): ");
- EXPECT_ZR(1, sigismember(&sa.sa_mask, SIGUSR2));
- /* _NSIG is the highest valid number and may not be in the
first word */
- sigaddset(&sa.sa_mask, _NSIG);
- llen = printf(" sa_mask.sig[%d] (_NSIG set): ",
(int)_NSIG_WORDS - 1);
- EXPECT_EQ(1, sa.sa_mask.sig[_NSIG_WORDS - 1],
1UL << (_NSIG - (_NSIG_WORDS - 1) * _NSIG_BPW
- 1));
- llen = printf(" sa_mask.sig[%d] (test _NSIG): ",
(int)_NSIG_WORDS - 1);
- EXPECT_NZ(1, sigismember(&sa.sa_mask, _NSIG));
- sigdelset(&sa.sa_mask, _NSIG);
- llen = printf(" sa_mask.sig[%d] (_NSIG unset): ",
(int)_NSIG_WORDS - 1);
- EXPECT_ZR(1, sigismember(&sa.sa_mask, _NSIG));
+#endif
This is more testing than expected, but that's good. Could you move it to a dedicated test function, gated on "is_nolibc" and the #ifdef.
It did find the bit shift type bug in the macros :-)
Benjamin
- /* sa_mask is empty at this point, set SIGUSR2 to verify
masking */
- sigaddset(&sa.sa_mask, SIGUSR2);
- res = sigaction(SIGUSR1, &sa, &sa_old);
- llen = printf(" register SIGUSR1: %d", res);
- EXPECT_SYSZR(1, res);
- if (res)
goto out;- llen = printf(" sa_old.sa_handler: SIG_DFL (%p)",
SIG_DFL);
- EXPECT_PTREQ(1, SIG_DFL, sa_old.sa_handler);
- if (res)
goto out;- res = sigaction(SIGUSR2, &sa, NULL);
- llen = printf(" register SIGUSR2: %d", res);
- EXPECT_SYSZR(1, res);
- if (res)
goto out;- /* Trigger the first signal. */
- kill(getpid(), SIGUSR1);
- /* Check the two signal handlers ran in the expected order
*/
- llen = printf(" signal emission: ");
- EXPECT_STEPS(1, signal_check, 2);
+out:
- sa.sa_handler = SIG_DFL;
- res = sigaction(SIGUSR1, &sa, NULL);
- llen = printf(" restore SIGUSR1: %d", res);
- EXPECT_SYSZR(1, res);
- res = sigaction(SIGUSR1, &sa, NULL);
SIGUSR2?
- llen = printf(" restore SIGUSR2: %d", res);
- EXPECT_SYSZR(1, res);
- llen = printf("%d %s", test_idx, "sigaction");
- EXPECT_EQ(1, res, 0);
- return ret;
+}
/* Run syscall tests between IDs <min> and <max>. * Return 0 on success, non-zero on failure. */ @@ -1421,6 +1535,7 @@ int run_syscall(int min, int max) CASE_TEST(syscall_noargs); EXPECT_SYSEQ(1, syscall(__NR_getpid), getpid()); break; CASE_TEST(syscall_args); EXPECT_SYSER(1, syscall(__NR_statx, 0, NULL, 0, 0, NULL), -1, EFAULT); break; CASE_TEST(namespace); EXPECT_SYSZR(euid0 && proc, test_namespace()); break;
case __LINE__: ret +=test_signals(test); break; case __LINE__: return ret; /* must be last */ /* note: do not set any defaults so as to permit holes above */ -- 2.50.0