Add tests to assert that PIDFD_SELF correctly refers to the current process.
This is only practically meaningful to pidfd_send_signal() and pidfd_getfd(), but also explicitly test that we disallow this feature for setns() where it would make no sense.
We cannot reasonably wait on ourself using waitid(P_PIDFD, ...) so while in theory PIDFD_SELF would work here, we'd be left blocked if we tried it.
We defer testing of mm-specific functionality which uses pidfd, namely process_madvise() and process_mrelease() to mm testing (though note the latter can not be sensibly tested as it would require the testing process to be dying).
Signed-off-by: Lorenzo Stoakes lorenzo.stoakes@oracle.com --- tools/testing/selftests/pidfd/pidfd.h | 5 +++ .../selftests/pidfd/pidfd_getfd_test.c | 38 +++++++++++++++++++ .../selftests/pidfd/pidfd_setns_test.c | 6 +++ tools/testing/selftests/pidfd/pidfd_test.c | 13 +++++++ 4 files changed, 62 insertions(+)
diff --git a/tools/testing/selftests/pidfd/pidfd.h b/tools/testing/selftests/pidfd/pidfd.h index 88d6830ee004..099ee7178193 100644 --- a/tools/testing/selftests/pidfd/pidfd.h +++ b/tools/testing/selftests/pidfd/pidfd.h @@ -50,6 +50,11 @@ #define PIDFD_NONBLOCK O_NONBLOCK #endif
+/* System header file may not have this available. */ +#ifndef PIDFD_SELF +#define PIDFD_SELF -200 +#endif + /* * The kernel reserves 300 pids via RESERVED_PIDS in kernel/pid.c * That means, when it wraps around any pid < 300 will be skipped. diff --git a/tools/testing/selftests/pidfd/pidfd_getfd_test.c b/tools/testing/selftests/pidfd/pidfd_getfd_test.c index cd51d547b751..cdf375fd61b2 100644 --- a/tools/testing/selftests/pidfd/pidfd_getfd_test.c +++ b/tools/testing/selftests/pidfd/pidfd_getfd_test.c @@ -15,6 +15,7 @@ #include <sys/prctl.h> #include <sys/wait.h> #include <unistd.h> +#include <sys/mman.h> #include <sys/socket.h> #include <linux/kcmp.h>
@@ -264,6 +265,43 @@ TEST_F(child, no_strange_EBADF) EXPECT_EQ(errno, ESRCH); }
+TEST(pidfd_self) +{ + int memfd = sys_memfd_create("test_self", 0); + long page_size = sysconf(_SC_PAGESIZE); + int newfd; + char *ptr; + + ASSERT_GE(memfd, 0); + ASSERT_EQ(ftruncate(memfd, page_size), 0); + + /* + * Map so we can assert that the duplicated fd references the same + * memory. + */ + ptr = mmap(NULL, page_size, PROT_READ | PROT_WRITE, + MAP_SHARED, memfd, 0); + ASSERT_NE(ptr, MAP_FAILED); + ptr[0] = 'x'; + ASSERT_EQ(munmap(ptr, page_size), 0); + + /* Now get a duplicate of our memfd. */ + newfd = sys_pidfd_getfd(PIDFD_SELF, memfd, 0); + ASSERT_GE(newfd, 0); + ASSERT_NE(memfd, newfd); + + /* Now map duplicate fd and make sure it references the same memory. */ + ptr = mmap(NULL, page_size, PROT_READ | PROT_WRITE, + MAP_SHARED, newfd, 0); + ASSERT_NE(ptr, MAP_FAILED); + ASSERT_EQ(ptr[0], 'x'); + ASSERT_EQ(munmap(ptr, page_size), 0); + + /* Cleanup. */ + close(memfd); + close(newfd); +} + #if __NR_pidfd_getfd == -1 int main(void) { diff --git a/tools/testing/selftests/pidfd/pidfd_setns_test.c b/tools/testing/selftests/pidfd/pidfd_setns_test.c index 7c2a4349170a..8e1510744aaa 100644 --- a/tools/testing/selftests/pidfd/pidfd_setns_test.c +++ b/tools/testing/selftests/pidfd/pidfd_setns_test.c @@ -752,4 +752,10 @@ TEST(setns_einval) close(fd); }
+TEST(setns_pidfd_self_disallowed) +{ + ASSERT_EQ(setns(PIDFD_SELF, 0), -1); + EXPECT_EQ(errno, EBADF); +} + TEST_HARNESS_MAIN diff --git a/tools/testing/selftests/pidfd/pidfd_test.c b/tools/testing/selftests/pidfd/pidfd_test.c index 9faa686f90e4..18802b657352 100644 --- a/tools/testing/selftests/pidfd/pidfd_test.c +++ b/tools/testing/selftests/pidfd/pidfd_test.c @@ -85,6 +85,19 @@ static int test_pidfd_send_signal_simple_success(void) test_name);
signal_received = 0; + + /* Now try the same thing only using PIDFD_SELF. */ + ret = sys_pidfd_send_signal(PIDFD_SELF, SIGUSR1, NULL, 0); + if (ret < 0) + ksft_exit_fail_msg("%s test: Failed to send PIDFD_SELF signal\n", + test_name); + + if (signal_received != 1) + ksft_exit_fail_msg("%s test: Failed to receive PIDFD_SELF signal\n", + test_name); + + signal_received = 0; + ksft_test_result_pass("%s test: Sent signal\n", test_name); return 0; }