From 914e6b1e85c5715ca2e7ec6293c05c71e9a98e86 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Tue, 24 Jun 2025 10:29:14 +0200 Subject: [PATCH] selftests/pidfd: decode pidfd file handles withou having to specify an fd Link: https://lore.kernel.org/20250624-work-pidfs-fhandle-v2-11-d02a04858fe3@kernel.org Reviewed-by: Jan Kara Reviewed-by: Amir Goldstein Signed-off-by: Christian Brauner --- tools/testing/selftests/pidfd/Makefile | 2 +- tools/testing/selftests/pidfd/pidfd.h | 4 ++ .../selftests/pidfd/pidfd_file_handle_test.c | 60 +++++++++++++++++++ 3 files changed, 65 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/pidfd/Makefile b/tools/testing/selftests/pidfd/Makefile index 03a6eede9c9e..764a8f9ecefa 100644 --- a/tools/testing/selftests/pidfd/Makefile +++ b/tools/testing/selftests/pidfd/Makefile @@ -1,5 +1,5 @@ # SPDX-License-Identifier: GPL-2.0-only -CFLAGS += -g $(KHDR_INCLUDES) -pthread -Wall +CFLAGS += -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES) -pthread -Wall TEST_GEN_PROGS := pidfd_test pidfd_fdinfo_test pidfd_open_test \ pidfd_poll_test pidfd_wait pidfd_getfd_test pidfd_setns_test \ diff --git a/tools/testing/selftests/pidfd/pidfd.h b/tools/testing/selftests/pidfd/pidfd.h index 5dfeb1bdf399..cd244d0860ff 100644 --- a/tools/testing/selftests/pidfd/pidfd.h +++ b/tools/testing/selftests/pidfd/pidfd.h @@ -19,6 +19,10 @@ #include "../kselftest.h" #include "../clone3/clone3_selftests.h" +#ifndef FD_PIDFS_ROOT +#define FD_PIDFS_ROOT -10002 +#endif + #ifndef P_PIDFD #define P_PIDFD 3 #endif diff --git a/tools/testing/selftests/pidfd/pidfd_file_handle_test.c b/tools/testing/selftests/pidfd/pidfd_file_handle_test.c index 439b9c6c0457..6bd2e9c9565b 100644 --- a/tools/testing/selftests/pidfd/pidfd_file_handle_test.c +++ b/tools/testing/selftests/pidfd/pidfd_file_handle_test.c @@ -500,4 +500,64 @@ TEST_F(file_handle, valid_name_to_handle_at_flags) ASSERT_EQ(close(pidfd), 0); } +/* + * That we decode a file handle without having to pass a pidfd. + */ +TEST_F(file_handle, decode_purely_based_on_file_handle) +{ + int mnt_id; + struct file_handle *fh; + int pidfd = -EBADF; + struct stat st1, st2; + + fh = malloc(sizeof(struct file_handle) + MAX_HANDLE_SZ); + ASSERT_NE(fh, NULL); + memset(fh, 0, sizeof(struct file_handle) + MAX_HANDLE_SZ); + fh->handle_bytes = MAX_HANDLE_SZ; + + ASSERT_EQ(name_to_handle_at(self->child_pidfd1, "", fh, &mnt_id, AT_EMPTY_PATH), 0); + + ASSERT_EQ(fstat(self->child_pidfd1, &st1), 0); + + pidfd = open_by_handle_at(FD_PIDFS_ROOT, fh, 0); + ASSERT_GE(pidfd, 0); + + ASSERT_EQ(fstat(pidfd, &st2), 0); + ASSERT_TRUE(st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino); + + ASSERT_EQ(close(pidfd), 0); + + pidfd = open_by_handle_at(FD_PIDFS_ROOT, fh, O_CLOEXEC); + ASSERT_GE(pidfd, 0); + + ASSERT_EQ(fstat(pidfd, &st2), 0); + ASSERT_TRUE(st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino); + + ASSERT_EQ(close(pidfd), 0); + + pidfd = open_by_handle_at(FD_PIDFS_ROOT, fh, O_NONBLOCK); + ASSERT_GE(pidfd, 0); + + ASSERT_EQ(fstat(pidfd, &st2), 0); + ASSERT_TRUE(st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino); + + ASSERT_EQ(close(pidfd), 0); + + pidfd = open_by_handle_at(self->pidfd, fh, 0); + ASSERT_GE(pidfd, 0); + + ASSERT_EQ(fstat(pidfd, &st2), 0); + ASSERT_TRUE(st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino); + + ASSERT_EQ(close(pidfd), 0); + + pidfd = open_by_handle_at(-EBADF, fh, 0); + ASSERT_LT(pidfd, 0); + + pidfd = open_by_handle_at(AT_FDCWD, fh, 0); + ASSERT_LT(pidfd, 0); + + free(fh); +} + TEST_HARNESS_MAIN -- 2.25.1