On 10/10/24 12:15, Lorenzo Stoakes wrote:
Add tests to assert that PIDFD_SELF_* correctly refers to the current thread and 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 | 8 ++ .../selftests/pidfd/pidfd_getfd_test.c | 136 ++++++++++++++++++ .../selftests/pidfd/pidfd_setns_test.c | 11 ++ tools/testing/selftests/pidfd/pidfd_test.c | 67 +++++++-- 4 files changed, 213 insertions(+), 9 deletions(-)
diff --git a/tools/testing/selftests/pidfd/pidfd.h b/tools/testing/selftests/pidfd/pidfd.h index 88d6830ee004..1640b711889b 100644 --- a/tools/testing/selftests/pidfd/pidfd.h +++ b/tools/testing/selftests/pidfd/pidfd.h @@ -50,6 +50,14 @@ #define PIDFD_NONBLOCK O_NONBLOCK #endif +/* System header file may not have this available. */ +#ifndef PIDFD_SELF_THREAD +#define PIDFD_SELF_THREAD -100 +#endif +#ifndef PIDFD_SELF_THREAD_GROUP +#define PIDFD_SELF_THREAD_GROUP -200 +#endif
Can't we pick these up from linux/pidfd.h - patch 2/3 adds them.
/*
- 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..10793fc845ed 100644 --- a/tools/testing/selftests/pidfd/pidfd_getfd_test.c +++ b/tools/testing/selftests/pidfd/pidfd_getfd_test.c @@ -6,6 +6,7 @@ #include <limits.h> #include <linux/types.h> #include <poll.h> +#include <pthread.h> #include <sched.h> #include <signal.h> #include <stdio.h> @@ -15,6 +16,7 @@ #include <sys/prctl.h> #include <sys/wait.h> #include <unistd.h> +#include <sys/mman.h> #include <sys/socket.h> #include <linux/kcmp.h> @@ -114,6 +116,89 @@ static int child(int sk) return ret; } +static int __pidfd_self_thread_worker(unsigned long page_size) +{
- int memfd;
- int newfd;
- char *ptr;
- int ret = 0;
- /*
* Unshare our FDs so we have our own set. This means* PIDFD_SELF_THREAD_GROUP will fail.*/- if (unshare(CLONE_FILES) < 0) {
ret = -errno;goto exit;- }
- /* Truncate, map in and write to our memfd. */
- memfd = sys_memfd_create("test_self_child", 0);
Missing eror check.
- if (ftruncate(memfd, page_size)) {
ret = -errno;goto exit;
Hmm. you probably need scoped cleanup paths. "exit" closes memfd and newfd which isn't open yet and sys_memfd_create() could fail and memfd doesn't need closing?
- }
- ptr = mmap(NULL, page_size, PROT_READ | PROT_WRITE,
MAP_SHARED, memfd, 0);- if (ptr == MAP_FAILED) {
ret = -errno;goto exit;- }
- ptr[0] = 'y';
- if (munmap(ptr, page_size)) {
ret = -errno;goto exit;- }
- /* Get a thread-local duplicate of our memfd. */
- newfd = sys_pidfd_getfd(PIDFD_SELF_THREAD, memfd, 0);
- if (newfd < 0) {
ret = -errno;goto exit;
Same comment here - "exit" closes newfd
- }
- if (memfd == newfd) {
ret = -EINVAL;goto exit;- }
- /* Map in new fd and make sure that the data is as expected. */
- ptr = mmap(NULL, page_size, PROT_READ | PROT_WRITE,
MAP_SHARED, newfd, 0);- if (ptr == MAP_FAILED) {
ret = -errno;goto exit;- }
- if (ptr[0] != 'y') {
ret = -EINVAL;goto exit;- }
- if (munmap(ptr, page_size)) {
ret = -errno;goto exit;- }
+exit:
- /* Cleanup. */
- close(newfd);
- close(memfd);
- return ret;
+}
+static void *pidfd_self_thread_worker(void *arg) +{
- unsigned long page_size = (unsigned long)arg;
- int ret;
- ret = __pidfd_self_thread_worker(page_size);
Don't you want to check error here?
- return (void *)(intptr_t)ret;
+}
- FIXTURE(child) { /*
@@ -264,6 +349,57 @@ TEST_F(child, no_strange_EBADF) EXPECT_EQ(errno, ESRCH); } +TEST(pidfd_self) +{
- int memfd = sys_memfd_create("test_self", 0);
- unsigned long page_size = sysconf(_SC_PAGESIZE);
- int newfd;
- char *ptr;
- pthread_t thread;
- void *res;
- int err;
- 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_THREAD_GROUP, 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);
- /*
* Fire up the thread and assert that we can lookup the thread-specific* PIDFD_SELF_THREAD (also aliased by PIDFD_SELF).*/- ASSERT_EQ(pthread_create(&thread, NULL, pidfd_self_thread_worker,
(void *)page_size), 0);- ASSERT_EQ(pthread_join(thread, &res), 0);
- err = (int)(intptr_t)res;
- ASSERT_EQ(err, 0);
+}
- #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..bbd39dc5ceb7 100644 --- a/tools/testing/selftests/pidfd/pidfd_setns_test.c +++ b/tools/testing/selftests/pidfd/pidfd_setns_test.c @@ -752,4 +752,15 @@ TEST(setns_einval) close(fd); } +TEST(setns_pidfd_self_disallowed) +{
- ASSERT_EQ(setns(PIDFD_SELF_THREAD, 0), -1);
- EXPECT_EQ(errno, EBADF);
- errno = 0;
- ASSERT_EQ(setns(PIDFD_SELF_THREAD_GROUP, 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..ab5caa0368a1 100644 --- a/tools/testing/selftests/pidfd/pidfd_test.c +++ b/tools/testing/selftests/pidfd/pidfd_test.c @@ -42,12 +42,41 @@ static pid_t pidfd_clone(int flags, int *pidfd, int (*fn)(void *)) #endif } -static int signal_received; +static pthread_t signal_received; static void set_signal_received_on_sigusr1(int sig) { if (sig == SIGUSR1)
signal_received = 1;
signal_received = pthread_self();+}
+static int send_signal(int pidfd) +{
- int ret = 0;
- if (sys_pidfd_send_signal(pidfd, SIGUSR1, NULL, 0) < 0) {
ret = -EINVAL;goto exit;- }
- if (signal_received != pthread_self()) {
ret = -EINVAL;goto exit;- }
+exit:
- signal_received = 0;
- return ret;
+}
+static void *send_signal_worker(void *arg) +{
- int pidfd = (int)(intptr_t)arg;
- int ret;
- ret = send_signal(pidfd);
Same here - don't you have to check ret?
- return (void *)(intptr_t)ret; }
/* @@ -56,8 +85,11 @@ static void set_signal_received_on_sigusr1(int sig) */ static int test_pidfd_send_signal_simple_success(void) {
- int pidfd, ret;
- int pidfd; const char *test_name = "pidfd_send_signal send SIGUSR1";
- pthread_t thread;
- void *thread_res;
- int res;
if (!have_pidfd_send_signal) { ksft_test_result_skip( @@ -74,17 +106,34 @@ static int test_pidfd_send_signal_simple_success(void) signal(SIGUSR1, set_signal_received_on_sigusr1);
- ret = sys_pidfd_send_signal(pidfd, SIGUSR1, NULL, 0);
- send_signal(pidfd); close(pidfd);
- if (ret < 0)
ksft_exit_fail_msg("%s test: Failed to send signal\n",
- /* Now try the same thing only using PIDFD_SELF_THREAD_GROUP. */
- res = send_signal(PIDFD_SELF_THREAD_GROUP);
- if (res)
ksft_exit_fail_msg("%s test: Error %d on PIDFD_SELF_THREAD_GROUP signal\n",test_name, res);- /*
* Now try the same thing in a thread and assert thread ID is equal to* worker thread ID.*/- if (pthread_create(&thread, NULL, send_signal_worker,
(void *)(intptr_t)PIDFD_SELF_THREAD))ksft_exit_fail_msg("%s test: Failed to create thread\n", test_name);
- if (signal_received != 1)
ksft_exit_fail_msg("%s test: Failed to receive signal\n",
- if (pthread_join(thread, &thread_res))
ksft_exit_fail_msg("%s test: Failed to join thread\n", test_name);- res = (int)(intptr_t)thread_res;
- if (res)
ksft_exit_fail_msg("%s test: Error %d on PIDFD_SELF_THREAD signal\n",test_name, res);
- signal_received = 0; ksft_test_result_pass("%s test: Sent signal\n", test_name); return 0; }
thanks, -- Shuah