Test that CLONE3_CLEAR_SIGHAND resets signal handlers to SIG_DFL for the child process and that CLONE3_CLEAR_SIGHAND and CLONE_SIGHAND are mutually exclusive.
Cc: Florian Weimer fweimer@redhat.com Cc: libc-alpha@sourceware.org Cc: linux-api@vger.kernel.org Signed-off-by: Christian Brauner christian.brauner@ubuntu.com --- /* v1 */ Link: https://lore.kernel.org/r/20191010133518.5420-2-christian.brauner@ubuntu.com
/* v2 */ - Christian Brauner christian.brauner@ubuntu.com: - remove unused variable - reuse variable in child process instead od declaring a new one - move check for mutual exclusivity of CLONE_SIGHAND and CLONE3_CLEAR_SIGHAND to top of test before setting up signal handlers - rename variables --- MAINTAINERS | 1 + tools/testing/selftests/Makefile | 1 + tools/testing/selftests/clone3/.gitignore | 1 + tools/testing/selftests/clone3/Makefile | 7 + .../selftests/clone3/clone3_clear_sighand.c | 172 ++++++++++++++++++ 5 files changed, 182 insertions(+) create mode 100644 tools/testing/selftests/clone3/.gitignore create mode 100644 tools/testing/selftests/clone3/Makefile create mode 100644 tools/testing/selftests/clone3/clone3_clear_sighand.c
diff --git a/MAINTAINERS b/MAINTAINERS index 55199ef7fa74..582275d85607 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -12828,6 +12828,7 @@ S: Maintained T: git git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux.git F: samples/pidfd/ F: tools/testing/selftests/pidfd/ +F: tools/testing/selftests/clone3/ K: (?i)pidfd K: (?i)clone3 K: \b(clone_args|kernel_clone_args)\b diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index c3feccb99ff5..6bf7aeb47650 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -4,6 +4,7 @@ TARGETS += bpf TARGETS += breakpoints TARGETS += capabilities TARGETS += cgroup +TARGETS += clone3 TARGETS += cpufreq TARGETS += cpu-hotplug TARGETS += drivers/dma-buf diff --git a/tools/testing/selftests/clone3/.gitignore b/tools/testing/selftests/clone3/.gitignore new file mode 100644 index 000000000000..6c9f98097774 --- /dev/null +++ b/tools/testing/selftests/clone3/.gitignore @@ -0,0 +1 @@ +clone3_clear_sighand diff --git a/tools/testing/selftests/clone3/Makefile b/tools/testing/selftests/clone3/Makefile new file mode 100644 index 000000000000..3ecd56ebc99d --- /dev/null +++ b/tools/testing/selftests/clone3/Makefile @@ -0,0 +1,7 @@ +# SPDX-License-Identifier: GPL-2.0-only +CFLAGS += -g -I../../../../usr/include/ + +TEST_GEN_PROGS := clone3_clear_sighand + +include ../lib.mk + diff --git a/tools/testing/selftests/clone3/clone3_clear_sighand.c b/tools/testing/selftests/clone3/clone3_clear_sighand.c new file mode 100644 index 000000000000..1a3adc206e74 --- /dev/null +++ b/tools/testing/selftests/clone3/clone3_clear_sighand.c @@ -0,0 +1,172 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#define _GNU_SOURCE +#include <errno.h> +#include <sched.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <linux/sched.h> +#include <linux/types.h> +#include <sys/syscall.h> +#include <sys/wait.h> + +#include "../kselftest.h" + +#ifndef CLONE3_CLEAR_SIGHAND +#define CLONE3_CLEAR_SIGHAND 0x100000000ULL +#endif + +#ifndef __NR_clone3 +#define __NR_clone3 -1 +struct clone_args { + __aligned_u64 flags; + __aligned_u64 pidfd; + __aligned_u64 child_tid; + __aligned_u64 parent_tid; + __aligned_u64 exit_signal; + __aligned_u64 stack; + __aligned_u64 stack_size; + __aligned_u64 tls; +}; +#endif + +static pid_t sys_clone3(struct clone_args *args, size_t size) +{ + return syscall(__NR_clone3, args, size); +} + +static void test_clone3_supported(void) +{ + pid_t pid; + struct clone_args args = {}; + + if (__NR_clone3 < 0) + ksft_exit_skip("clone3() syscall is not supported\n"); + + /* Set to something that will always cause EINVAL. */ + args.exit_signal = -1; + pid = sys_clone3(&args, sizeof(args)); + if (!pid) + exit(EXIT_SUCCESS); + + if (pid > 0) { + wait(NULL); + ksft_exit_fail_msg( + "Managed to create child process with invalid exit_signal\n"); + } + + if (errno == ENOSYS) + ksft_exit_skip("clone3() syscall is not supported\n"); + + ksft_print_msg("clone3() syscall supported\n"); +} + +static void nop_handler(int signo) +{ +} + +static int wait_for_pid(pid_t pid) +{ + int status, ret; + +again: + ret = waitpid(pid, &status, 0); + if (ret == -1) { + if (errno == EINTR) + goto again; + + return -1; + } + + if (!WIFEXITED(status)) + return -1; + + return WEXITSTATUS(status); +} + +static void test_clone3_clear_sighand(void) +{ + int ret; + pid_t pid; + struct clone_args args = {}; + struct sigaction act; + + /* + * Check that CLONE3_CLEAR_SIGHAND and CLONE_SIGHAND are mutually + * exclusive. + */ + args.flags |= CLONE3_CLEAR_SIGHAND | CLONE_SIGHAND; + args.exit_signal = SIGCHLD; + pid = sys_clone3(&args, sizeof(args)); + if (pid > 0) + ksft_exit_fail_msg( + "clone3(CLONE3_CLEAR_SIGHAND | CLONE_SIGHAND) succeeded\n"); + + act.sa_handler = nop_handler; + ret = sigemptyset(&act.sa_mask); + if (ret < 0) + ksft_exit_fail_msg("%s - sigemptyset() failed\n", + strerror(errno)); + + act.sa_flags = 0; + + /* Register signal handler for SIGUSR1 */ + ret = sigaction(SIGUSR1, &act, NULL); + if (ret < 0) + ksft_exit_fail_msg( + "%s - sigaction(SIGUSR1, &act, NULL) failed\n", + strerror(errno)); + + /* Register signal handler for SIGUSR2 */ + ret = sigaction(SIGUSR2, &act, NULL); + if (ret < 0) + ksft_exit_fail_msg( + "%s - sigaction(SIGUSR2, &act, NULL) failed\n", + strerror(errno)); + + /* Check that CLONE3_CLEAR_SIGHAND works. */ + args.flags = CLONE3_CLEAR_SIGHAND; + pid = sys_clone3(&args, sizeof(args)); + if (pid < 0) + ksft_exit_fail_msg("%s - clone3(CLONE3_CLEAR_SIGHAND) failed\n", + strerror(errno)); + + if (pid == 0) { + ret = sigaction(SIGUSR1, NULL, &act); + if (ret < 0) + exit(EXIT_FAILURE); + + if (act.sa_handler != SIG_DFL) + exit(EXIT_FAILURE); + + ret = sigaction(SIGUSR2, NULL, &act); + if (ret < 0) + exit(EXIT_FAILURE); + + if (act.sa_handler != SIG_DFL) + exit(EXIT_FAILURE); + + exit(EXIT_SUCCESS); + } + + ret = wait_for_pid(pid); + if (ret) + ksft_exit_fail_msg( + "Failed to clear signal handler for child process\n"); + + ksft_test_result_pass("Cleared signal handlers for child process\n"); +} + +int main(int argc, char **argv) +{ + ksft_print_header(); + ksft_set_plan(1); + + test_clone3_supported(); + test_clone3_clear_sighand(); + + return ksft_exit_pass(); +}