From: Benjamin Berg <[email protected]> In preparation to add tests that use it.
Note that some architectures do not have a usable linux/signal.h include file. However, in those cases we can use asm-generic/signal.h instead. Signed-off-by: Benjamin Berg <[email protected]> --- Another attempt at signal handling for nolibc which should actually be working. Some trickery is needed to get the right definition, but I feel it is sufficiently clean this way. Submitting this as RFC mostly because I do not yet have a proper patch to add a test that uses the feature. Benjamin --- tools/include/nolibc/arch-aarch64.h | 3 + tools/include/nolibc/arch-arm.h | 7 ++ tools/include/nolibc/arch-i386.h | 13 +++ 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-sparc.h | 43 +++++++++ tools/include/nolibc/arch-x86_64.h | 10 ++ tools/include/nolibc/signal.h | 97 ++++++++++++++++++++ tools/include/nolibc/sys.h | 2 +- tools/include/nolibc/time.h | 3 +- tools/testing/selftests/nolibc/nolibc-test.c | 52 +++++++++++ 15 files changed, 261 insertions(+), 4 deletions(-) diff --git a/tools/include/nolibc/arch-aarch64.h b/tools/include/nolibc/arch-aarch64.h index 937a348da42e..736aae6dbd47 100644 --- a/tools/include/nolibc/arch-aarch64.h +++ b/tools/include/nolibc/arch-aarch64.h @@ -10,6 +10,9 @@ #include "compiler.h" #include "crt.h" +/* Architecture has a usable linux/signal.h */ +#include <linux/signal.h> + /* Syscalls for AARCH64 : * - registers are 64-bit * - stack is 16-byte aligned diff --git a/tools/include/nolibc/arch-arm.h b/tools/include/nolibc/arch-arm.h index 1f66e7e5a444..1faf6c2dbeb8 100644 --- a/tools/include/nolibc/arch-arm.h +++ b/tools/include/nolibc/arch-arm.h @@ -10,6 +10,13 @@ #include "compiler.h" #include "crt.h" +/* Needed to get the correct struct sigaction definition */ +#define SA_RESTORER 0x04000000 + +/* Avoid linux/signal.h, it has an incorrect _NSIG and sigset_t */ +#include <asm-generic/signal.h> +#include <asm-generic/siginfo.h> + /* Syscalls for ARM in ARM or Thumb modes : * - registers are 32-bit * - stack is 8-byte aligned diff --git a/tools/include/nolibc/arch-i386.h b/tools/include/nolibc/arch-i386.h index 7c9b38e96418..fbec7490a92c 100644 --- a/tools/include/nolibc/arch-i386.h +++ b/tools/include/nolibc/arch-i386.h @@ -10,6 +10,19 @@ #include "compiler.h" #include "crt.h" +/* Needed to get the correct struct sigaction definition */ +#define SA_RESTORER 0x04000000 + +/* Restorer must be set on i386 */ +#define _NOLIBC_ARCH_NEEDS_SA_RESTORER + +/* Otherwise we would need to use sigreturn instead of rt_sigreturn */ +#define _NOLIBC_ARCH_FORCE_SIG_FLAGS SA_SIGINFO + +/* Avoid linux/signal.h, it has an incorrect _NSIG and sigset_t */ +#include <asm-generic/signal.h> +#include <asm-generic/siginfo.h> + /* Syscalls for i386 : * - mostly similar to x86_64 * - registers are 32-bit diff --git a/tools/include/nolibc/arch-loongarch.h b/tools/include/nolibc/arch-loongarch.h index 5511705303ea..68d60d04ef59 100644 --- a/tools/include/nolibc/arch-loongarch.h +++ b/tools/include/nolibc/arch-loongarch.h @@ -10,6 +10,9 @@ #include "compiler.h" #include "crt.h" +/* Architecture has a usable linux/signal.h */ +#include <linux/signal.h> + /* Syscalls for LoongArch : * - stack is 16-byte aligned * - syscall number is passed in a7 diff --git a/tools/include/nolibc/arch-m68k.h b/tools/include/nolibc/arch-m68k.h index 6dac1845f298..981b4cc55a69 100644 --- a/tools/include/nolibc/arch-m68k.h +++ b/tools/include/nolibc/arch-m68k.h @@ -13,6 +13,16 @@ #include "compiler.h" #include "crt.h" +/* + * Needed to get the correct struct sigaction definition. m68k does not use + * sa_restorer, but it is included in the structure. + */ +#define SA_RESTORER 0x04000000 + +/* Avoid linux/signal.h, it has an incorrect _NSIG and sigset_t */ +#include <asm-generic/signal.h> +#include <asm-generic/siginfo.h> + #define _NOLIBC_SYSCALL_CLOBBERLIST "memory" #define my_syscall0(num) \ diff --git a/tools/include/nolibc/arch-mips.h b/tools/include/nolibc/arch-mips.h index 753a8ed2cf69..a8837452e744 100644 --- a/tools/include/nolibc/arch-mips.h +++ b/tools/include/nolibc/arch-mips.h @@ -14,6 +14,9 @@ #error Unsupported MIPS ABI #endif +/* Architecture has a usable linux/signal.h */ +#include <linux/signal.h> + /* Syscalls for MIPS ABI O32 : * - WARNING! there's always a delayed slot! * - WARNING again, the syntax is different, registers take a '$' and numbers diff --git a/tools/include/nolibc/arch-powerpc.h b/tools/include/nolibc/arch-powerpc.h index 204564bbcd32..c846a7ddcf3c 100644 --- a/tools/include/nolibc/arch-powerpc.h +++ b/tools/include/nolibc/arch-powerpc.h @@ -10,6 +10,14 @@ #include "compiler.h" #include "crt.h" +/* Needed to get the correct struct sigaction definition */ +#define SA_RESTORER 0x04000000 +#define _NOLIBC_ARCH_NEEDS_SA_RESTORER + +/* Avoid linux/signal.h, it has an incorrect _NSIG and sigset_t */ +#include <asm-generic/signal.h> +#include <asm-generic/siginfo.h> + /* Syscalls for PowerPC : * - stack is 16-byte aligned * - syscall number is passed in r0 diff --git a/tools/include/nolibc/arch-riscv.h b/tools/include/nolibc/arch-riscv.h index 885383a86c38..709e6a262d9a 100644 --- a/tools/include/nolibc/arch-riscv.h +++ b/tools/include/nolibc/arch-riscv.h @@ -10,6 +10,9 @@ #include "compiler.h" #include "crt.h" +/* Architecture has a usable linux/signal.h */ +#include <linux/signal.h> + /* Syscalls for RISCV : * - stack is 16-byte aligned * - syscall number is passed in a7 diff --git a/tools/include/nolibc/arch-s390.h b/tools/include/nolibc/arch-s390.h index df4c3cc713ac..0dccb6d1ad64 100644 --- a/tools/include/nolibc/arch-s390.h +++ b/tools/include/nolibc/arch-s390.h @@ -5,13 +5,19 @@ #ifndef _NOLIBC_ARCH_S390_H #define _NOLIBC_ARCH_S390_H -#include <linux/signal.h> #include <linux/unistd.h> #include "compiler.h" #include "crt.h" #include "std.h" +/* Needed to get the correct struct sigaction definition */ +#define SA_RESTORER 0x04000000 + +/* Avoid linux/signal.h, it has an incorrect _NSIG and sigset_t */ +#include <asm-generic/signal.h> +#include <asm-generic/siginfo.h> + /* Syscalls for s390: * - registers are 64-bit * - syscall number is passed in r1 diff --git a/tools/include/nolibc/arch-sparc.h b/tools/include/nolibc/arch-sparc.h index 1435172f3dfe..303291d4b8fb 100644 --- a/tools/include/nolibc/arch-sparc.h +++ b/tools/include/nolibc/arch-sparc.h @@ -12,6 +12,19 @@ #include "compiler.h" #include "crt.h" +/* Otherwise we would need to use sigreturn instead of rt_sigreturn */ +#define _NOLIBC_ARCH_FORCE_SIG_FLAGS SA_SIGINFO + +/* The includes are sane, if one sets __WANT_POSIX1B_SIGNALS__ */ +#define __WANT_POSIX1B_SIGNALS__ +#include <linux/signal.h> + +/* + * sparc has ODD_RT_SIGACTION, we always pass our restorer as an argument + * to rt_sigaction. The restorer is implemented in this file. + */ +#define _NOLIBC_RT_SIGACTION_PASSES_RESTORER + /* * Syscalls for SPARC: * - registers are native word size @@ -188,4 +201,34 @@ pid_t sys_fork(void) } #define sys_fork sys_fork +#define __nolibc_stringify_1(x...) #x +#define __nolibc_stringify(x...) __stringify_1(x) + +/* The compiler insists on adding a SAVE call to the start of every function */ +#define __nolibc_sa_restorer __nolibc_sa_restorer +void __nolibc_sa_restorer (void); +#ifdef __arch64__ +__asm__( \ + ".section .text\n" \ + ".align 4 \n" \ + "__nolibc_sa_restorer:\n" \ + "nop\n" \ + "nop\n" \ + "mov " __stringify(__NR_rt_sigreturn) ", %g1 \n" \ + "t 0x6d \n"); +#else +__asm__( \ + ".section .text\n" \ + ".align 4 \n" \ + "__nolibc_sa_restorer:\n" \ + "nop\n" \ + "nop\n" \ + "mov " __stringify(__NR_rt_sigreturn) ", %g1 \n" \ + "t 0x10 \n" \ + ); +#endif + +#undef __nolibc_stringify_1(x...) +#undef __nolibc_stringify + #endif /* _NOLIBC_ARCH_SPARC_H */ diff --git a/tools/include/nolibc/arch-x86_64.h b/tools/include/nolibc/arch-x86_64.h index 67305e24dbef..9f13a2205876 100644 --- a/tools/include/nolibc/arch-x86_64.h +++ b/tools/include/nolibc/arch-x86_64.h @@ -10,6 +10,16 @@ #include "compiler.h" #include "crt.h" +/* Needed to get the correct struct sigaction definition */ +#define SA_RESTORER 0x04000000 + +/* Restorer must be set on i386 */ +#define _NOLIBC_ARCH_NEEDS_SA_RESTORER + +/* Avoid linux/signal.h, it has an incorrect _NSIG and sigset_t */ +#include <asm-generic/signal.h> +#include <asm-generic/siginfo.h> + /* Syscalls for x86_64 : * - registers are 64-bit * - syscall number is passed in rax diff --git a/tools/include/nolibc/signal.h b/tools/include/nolibc/signal.h index ac13e53ac31d..829672250ede 100644 --- a/tools/include/nolibc/signal.h +++ b/tools/include/nolibc/signal.h @@ -14,6 +14,8 @@ #include "arch.h" #include "types.h" #include "sys.h" +#include "string.h" +/* signal definitions are included by arch.h */ /* This one is not marked static as it's needed by libgcc for divide by zero */ int raise(int signal); @@ -23,4 +25,99 @@ int raise(int signal) return sys_kill(sys_getpid(), signal); } +/* + * sigaction(int signum, const struct sigaction *act, struct sigaction *oldact) + */ +#if defined(_NOLIBC_ARCH_NEEDS_SA_RESTORER) && !defined(__nolibc_sa_restorer) +static __attribute__((noreturn)) __nolibc_entrypoint __no_stack_protector +void __nolibc_sa_restorer(void) +{ + my_syscall0(__NR_rt_sigreturn); + __nolibc_entrypoint_epilogue(); +} +#endif + +static __attribute__((unused)) +int sys_rt_sigaction(int signum, const struct sigaction *act, struct sigaction *oldact) +{ + struct sigaction real_act = *act; +#if defined(SA_RESTORER) && defined(_NOLIBC_ARCH_NEEDS_SA_RESTORER) + if (!(real_act.sa_flags & SA_RESTORER)) { + real_act.sa_flags |= SA_RESTORER; + real_act.sa_restorer = __nolibc_sa_restorer; + } +#endif +#ifdef _NOLIBC_ARCH_FORCE_SIG_FLAGS + real_act.sa_flags |= _NOLIBC_ARCH_FORCE_SIG_FLAGS; +#endif + +#ifndef _NOLIBC_RT_SIGACTION_PASSES_RESTORER + return my_syscall4(__NR_rt_sigaction, signum, &real_act, oldact, + sizeof(act->sa_mask)); +#else + return my_syscall5(__NR_rt_sigaction, signum, &real_act, oldact, + __nolibc_sa_restorer, sizeof(act->sa_mask)); +#endif +} + +static __attribute__((unused)) +int sigaction(int signum, const struct sigaction *act, struct sigaction *oldact) +{ + return __sysret(sys_rt_sigaction(signum, act, oldact)); +} + +/* + * int sigemptyset(sigset_t *set) + */ +static __attribute__((unused)) +int sigemptyset(sigset_t *set) +{ + memset(set, 0, sizeof(*set)); + return 0; +} + +/* + * int sigfillset(sigset_t *set) + */ +static __attribute__((unused)) +int sigfillset(sigset_t *set) +{ + memset(set, 0xff, sizeof(*set)); + return 0; +} + +/* + * int sigaddset(sigset_t *set, int signum) + */ +static __attribute__((unused)) +int sigaddset(sigset_t *set, int signum) +{ + set->sig[(signum - 1) / (8 * sizeof(set->sig[0]))] |= + 1UL << ((signum - 1) % (8 * sizeof(set->sig[0]))); + return 0; +} + +/* + * int sigdelset(sigset_t *set, int signum) + */ +static __attribute__((unused)) +int sigdelset(sigset_t *set, int signum) +{ + set->sig[(signum - 1) / (8 * sizeof(set->sig[0]))] &= + ~(1UL << ((signum - 1) % (8 * sizeof(set->sig[0])))); + return 0; +} + +/* + * int sigismember(sigset_t *set, int signum) + */ +static __attribute__((unused)) +int sigismember(sigset_t *set, int signum) +{ + unsigned long res = + set->sig[(signum - 1) / (8 * sizeof(set->sig[0]))] & + (1UL << ((signum - 1) % (8 * sizeof(set->sig[0])))); + return !!res; +} + #endif /* _NOLIBC_SIGNAL_H */ diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h index 9556c69a6ae1..fb9a1ccf2440 100644 --- a/tools/include/nolibc/sys.h +++ b/tools/include/nolibc/sys.h @@ -14,7 +14,6 @@ /* system includes */ #include <linux/unistd.h> -#include <linux/signal.h> /* for SIGCHLD */ #include <linux/termios.h> #include <linux/mman.h> #include <linux/fs.h> @@ -23,6 +22,7 @@ #include <linux/auxvec.h> #include <linux/fcntl.h> /* for O_* and AT_* */ #include <linux/stat.h> /* for statx() */ +/* signal definitions are included by arch.h */ #include "errno.h" #include "stdarg.h" diff --git a/tools/include/nolibc/time.h b/tools/include/nolibc/time.h index fc387940d51f..70ef31d4117f 100644 --- a/tools/include/nolibc/time.h +++ b/tools/include/nolibc/time.h @@ -14,9 +14,8 @@ #include "arch.h" #include "types.h" #include "sys.h" - -#include <linux/signal.h> #include <linux/time.h> +/* signal definitions are included by arch.h */ static __inline__ void __nolibc_timespec_user_to_kernel(const struct timespec *ts, struct __kernel_timespec *kts) diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index dbe13000fb1a..af66b739ea18 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -1750,6 +1750,57 @@ static int run_protection(int min __attribute__((unused)), } } +volatile int signal_check; + +void test_sighandler(int signum) +{ + if (signum == SIGUSR1) { + kill(getpid(), SIGUSR2); + signal_check = 1; + } else { + signal_check++; + } +} + +int run_signal(int min, int max) +{ + struct sigaction sa = { + .sa_flags = 0, + .sa_handler = test_sighandler, + }; + int llen; /* line length */ + int ret = 0; + int res; + + (void)min; + (void)max; + + signal_check = 0; + + sigemptyset(&sa.sa_mask); + sigaddset(&sa.sa_mask, SIGUSR2); + + res = sigaction(SIGUSR1, &sa, NULL); + llen = printf("register SIGUSR1: %d", res); + EXPECT_EQ(1, 0, res); + res = sigaction(SIGUSR2, &sa, NULL); + llen = printf("register SIGUSR2: %d", res); + EXPECT_EQ(1, 0, res); + + /* Trigger the first signal. */ + kill(getpid(), SIGUSR1); + + /* If signal_check is 1 or higher, then signal emission worked */ + llen = printf("signal emission: 1 <= signal_check"); + EXPECT_GE(1, signal_check, 1); + + /* If it is 2, then signal masking worked */ + llen = printf("signal masking: 2 == signal_check"); + EXPECT_EQ(1, signal_check, 2); + + return ret; +} + /* prepare what needs to be prepared for pid 1 (stdio, /dev, /proc, etc) */ int prepare(void) { @@ -1815,6 +1866,7 @@ static const struct test test_names[] = { { .name = "stdlib", .func = run_stdlib }, { .name = "printf", .func = run_printf }, { .name = "protection", .func = run_protection }, + { .name = "signal", .func = run_signal }, { 0 } }; -- 2.50.0
