KVM: selftests: Add strnlen() to the string overrides

Add strnlen() to the string overrides to allow it to be called in the
guest.

The implementation for strnlen() was taken from the kernel's generic
version, lib/string.c.

This will be needed when printf() is introduced.

Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Link: https://lore.kernel.org/r/20230729003643.1053367-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index c692cc8..f6c14ab 100644 (file)
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -204,6 +204,7 @@ endif
 CFLAGS += -Wall -Wstrict-prototypes -Wuninitialized -O2 -g -std=gnu99 \
        -Wno-gnu-variable-sized-type-not-at-end -MD\
        -fno-builtin-memcmp -fno-builtin-memcpy -fno-builtin-memset \
+       -fno-builtin-strnlen \
        -fno-stack-protector -fno-PIE -I$(LINUX_TOOL_INCLUDE) \
        -I$(LINUX_TOOL_ARCH_INCLUDE) -I$(LINUX_HDR_PATH) -Iinclude \
        -I$(<D) -Iinclude/$(ARCH_DIR) -I ../rseq -I.. $(EXTRA_CFLAGS) \

diff --git a/tools/testing/selftests/kvm/lib/string_override.c b/tools/testing/selftests/kvm/lib/string_override.c
index 632398a..5d1c872 100644 (file)
--- a/tools/testing/selftests/kvm/lib/string_override.c
+++ b/tools/testing/selftests/kvm/lib/string_override.c
@@ -37,3 +37,12 @@ void *memset(void *s, int c, size_t count)
                *xs++ = c;
        return s;
 }
+
+size_t strnlen(const char *s, size_t count)
+{
+       const char *sc;
+
+       for (sc = s; count-- && *sc != '\0'; ++sc)
+               /* nothing */;
+       return sc - s;
+}