diff mbox series

[2/7] KVM: selftests: Use pread() to read binary stats header

Message ID 20230711230131.648752-3-seanjc@google.com
State New
Headers
Series KVM: Grab KVM references for stats fds |

Commit Message

Sean Christopherson July 11, 2023, 11:01 p.m. UTC 
  Use pread() with an explicit offset when reading the header and the header
name for a binary stats fd so that the common helper and the binary stats
test don't subtly rely on the file effectively being untouched, e.g. to
allow multiple reads of the header, name, etc.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 tools/testing/selftests/kvm/include/kvm_util_base.h | 6 ++++--
 tools/testing/selftests/kvm/kvm_binary_stats_test.c | 6 ++++--
 2 files changed, 8 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
index 07732a157ccd..eb1ff597bcca 100644
--- a/tools/testing/selftests/kvm/include/kvm_util_base.h
+++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
@@ -362,8 +362,10 @@  static inline void read_stats_header(int stats_fd, struct kvm_stats_header *head
 {
 	ssize_t ret;
 
-	ret = read(stats_fd, header, sizeof(*header));
-	TEST_ASSERT(ret == sizeof(*header), "Read stats header");
+	ret = pread(stats_fd, header, sizeof(*header), 0);
+	TEST_ASSERT(ret == sizeof(*header),
+		    "Failed to read '%lu' header bytes, ret = '%ld'",
+		    sizeof(*header), ret);
 }
 
 struct kvm_stats_desc *read_stats_descriptors(int stats_fd,
diff --git a/tools/testing/selftests/kvm/kvm_binary_stats_test.c b/tools/testing/selftests/kvm/kvm_binary_stats_test.c
index a7001e29dc06..eae99d0e8377 100644
--- a/tools/testing/selftests/kvm/kvm_binary_stats_test.c
+++ b/tools/testing/selftests/kvm/kvm_binary_stats_test.c
@@ -43,8 +43,10 @@  static void stats_test(int stats_fd)
 	id = malloc(header.name_size);
 	TEST_ASSERT(id, "Allocate memory for id string");
 
-	ret = read(stats_fd, id, header.name_size);
-	TEST_ASSERT(ret == header.name_size, "Read id string");
+	ret = pread(stats_fd, id, header.name_size, sizeof(header));
+	TEST_ASSERT(ret == header.name_size,
+		    "Expected header size '%u', read '%lu' bytes",
+		    header.name_size, ret);
 
 	/* Check id string, that should start with "kvm" */
 	TEST_ASSERT(!strncmp(id, "kvm", 3) && strlen(id) < header.name_size,