On Sat, Dec 29, 2018 at 11:27:56PM +0100, Christian Brauner wrote: > As suggested by Andrew Morton in [1] add selftests for the new > sys_pidfd_send_signal() syscall. > This tests whether we can send a signal to an existing process and whether > sending a signal to a process that has already exited fails with ESRCH. > > [1]: https://lore.kernel.org/lkml/20181228152012.dbf0508c2508138efc5f2bbe@xxxxxxxxxxxxxxxxxxxx/ > > Cc: Arnd Bergmann <arnd@xxxxxxxx> > Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> > Cc: Kees Cook <keescook@xxxxxxxxxxxx> > Cc: Serge Hallyn <serge@xxxxxxxxxx> Acked-by: Serge Hallyn <serge@xxxxxxxxxx> Not saying you need to do this, but it would be neat if you could test sending to a pid which has been recycled :) > Cc: Jann Horn <jannh@xxxxxxxxxx> > Cc: Andy Lutomirsky <luto@xxxxxxxxxx> > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Cc: Oleg Nesterov <oleg@xxxxxxxxxx> > Cc: Aleksa Sarai <cyphar@xxxxxxxxxx> > Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> > Cc: Florian Weimer <fweimer@xxxxxxxxxx> > Signed-off-by: Christian Brauner <christian@xxxxxxxxxx> > --- > /* Changelog */ > v6: > - patch introduced > v5..v0: > - patch not present > --- > tools/testing/selftests/Makefile | 1 + > tools/testing/selftests/pidfd/Makefile | 6 + > tools/testing/selftests/pidfd/pidfd_test.c | 130 +++++++++++++++++++++ > 3 files changed, 137 insertions(+) > create mode 100644 tools/testing/selftests/pidfd/Makefile > create mode 100644 tools/testing/selftests/pidfd/pidfd_test.c > > diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile > index 24b9934fb269..63b0d8a0ebf7 100644 > --- a/tools/testing/selftests/Makefile > +++ b/tools/testing/selftests/Makefile > @@ -27,6 +27,7 @@ TARGETS += net > TARGETS += netfilter > TARGETS += networking/timestamping > TARGETS += nsfs > +TARGETS += pidfd > TARGETS += powerpc > TARGETS += proc > TARGETS += pstore > diff --git a/tools/testing/selftests/pidfd/Makefile b/tools/testing/selftests/pidfd/Makefile > new file mode 100644 > index 000000000000..deaf8073bc06 > --- /dev/null > +++ b/tools/testing/selftests/pidfd/Makefile > @@ -0,0 +1,6 @@ > +CFLAGS += -g -I../../../../usr/include/ > + > +TEST_GEN_PROGS := pidfd_test > + > +include ../lib.mk > + > diff --git a/tools/testing/selftests/pidfd/pidfd_test.c b/tools/testing/selftests/pidfd/pidfd_test.c > new file mode 100644 > index 000000000000..edcd59979b10 > --- /dev/null > +++ b/tools/testing/selftests/pidfd/pidfd_test.c > @@ -0,0 +1,130 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +#define _GNU_SOURCE > +#include <errno.h> > +#include <fcntl.h> > +#include <linux/types.h> > +#include <signal.h> > +#include <stdio.h> > +#include <stdlib.h> > +#include <string.h> > +#include <syscall.h> > +#include <sys/wait.h> > +#include <unistd.h> > + > +#include "../kselftest.h" > + > +static inline int sys_pidfd_send_signal(int pidfd, int sig, siginfo_t *info, > + unsigned int flags) > +{ > + return syscall(__NR_pidfd_send_signal, pidfd, sig, info, flags); > +} > + > +static int signal_received; > + > +static void do_exit_success(int sig) > +{ > + signal_received = 1; > +} > + > +/* > + * Straightforward test to see whether pidfd_send_signal() works is to send > + * a signal to ourselves. > + */ > +static int test_pidfd_send_signal_simple_success(void) > +{ > + int pidfd, ret; > + const char *test_name = "pidfd_send_signal send SIGUSR1"; > + > + pidfd = open("/proc/self", O_DIRECTORY | O_CLOEXEC); > + if (pidfd < 0) > + ksft_exit_fail_msg( > + "%s test: Failed to open process file descriptor\n", > + test_name); > + > + signal(SIGUSR1, do_exit_success); > + > + ret = sys_pidfd_send_signal(pidfd, SIGUSR1, NULL, 0); > + close(pidfd); > + if (ret < 0) > + ksft_exit_fail_msg("%s test: Failed to send signal\n", > + test_name); > + > + if (signal_received != 1) > + ksft_exit_fail_msg("%s test: Failed to receive signal\n", > + test_name); > + > + signal_received = 0; > + ksft_test_result_pass("%s test: Sent signal\n", test_name); > + return 0; > +} > + > +static void wait_for_pid(pid_t pid) > +{ > + int status, ret; > + > +again: > + ret = waitpid(pid, &status, 0); > + if (ret == -1) { > + if (errno == EINTR) > + goto again; > + > + return; > + } > + > + if (ret != pid) > + goto again; > +} > + > +static int test_pidfd_send_signal_exited_fail(void) > +{ > + int pidfd, ret, saved_errno; > + char buf[256]; > + pid_t pid; > + const char *test_name = "pidfd_send_signal signal exited process"; > + > + pid = fork(); > + if (pid < 0) > + ksft_exit_fail_msg("%s test: Failed to create new process\n", > + test_name); > + > + if (pid == 0) > + _exit(EXIT_SUCCESS); > + > + snprintf(buf, sizeof(buf), "/proc/%d", pid); > + > + pidfd = open(buf, O_DIRECTORY | O_CLOEXEC); > + > + wait_for_pid(pid); > + > + if (pidfd < 0) > + ksft_exit_fail_msg( > + "%s test: Failed to open process file descriptor\n", > + test_name); > + > + ret = sys_pidfd_send_signal(pidfd, 0, NULL, 0); > + saved_errno = errno; > + close(pidfd); > + if (ret == 0) > + ksft_exit_fail_msg( > + "%s test: Managed to send signal to process even though it should have failed\n", > + test_name); > + > + if (saved_errno != ESRCH) > + ksft_exit_fail_msg( > + "%s test: Expected to receive ESRCH as errno value but received %d instead\n", > + test_name, saved_errno); > + > + ksft_test_result_pass("%s test: Failed to send signal as expected\n", > + test_name); > + return 0; > +} > + > +int main(int argc, char **argv) > +{ > + ksft_print_header(); > + > + test_pidfd_send_signal_simple_success(); > + test_pidfd_send_signal_exited_fail(); > + > + return ksft_exit_pass(); > +} > -- > 2.19.1
