From cc8824ad4e9486b9fa64f1b1d078ff1963f71219 Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Tue, 12 Apr 2016 11:51:05 +0100 Subject: [PATCH] [libc] Print "" for wide-character NULL strings The existing code intends to print NULL strings as "" (for the sake of debug messages), but the logic is incorrect when handling wide-character strings. Fix the logic and add applicable unit tests. Signed-off-by: Michael Brown --- src/core/vsprintf.c | 6 ++++-- src/tests/vsprintf_test.c | 4 ++++ 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/src/core/vsprintf.c b/src/core/vsprintf.c index cb3bec5d..9d3a97c2 100644 --- a/src/core/vsprintf.c +++ b/src/core/vsprintf.c @@ -257,11 +257,13 @@ size_t vcprintf ( struct printf_context *ctx, const char *fmt, va_list args ) { } else if ( *fmt == 's' ) { if ( length < &type_sizes[LONG_LEN] ) { ptr = va_arg ( args, char * ); + if ( ! ptr ) + ptr = ""; } else { wptr = va_arg ( args, wchar_t * ); + if ( ! wptr ) + ptr = ""; } - if ( ( ptr == NULL ) && ( wptr == NULL ) ) - ptr = ""; } else if ( *fmt == 'p' ) { intptr_t ptrval; diff --git a/src/tests/vsprintf_test.c b/src/tests/vsprintf_test.c index ad732a0d..f388b3de 100644 --- a/src/tests/vsprintf_test.c +++ b/src/tests/vsprintf_test.c @@ -108,6 +108,10 @@ static void vsprintf_test_exec ( void ) { snprintf_ok ( 64, "PCI 00:1f.3", "PCI %02x:%02x.%x", 0x00, 0x1f, 0x03 ); snprintf_ok ( 64, "Region [1000000,3f000000)", "Region [%llx,%llx)", 0x1000000ULL, 0x3f000000ULL ); + + /* Null string (used for debug messages) */ + snprintf_ok ( 16, "", "%s", ( ( char * ) NULL ) ); + snprintf_ok ( 16, "", "%ls", ( ( wchar_t * ) NULL ) ); } /** vsprintf() self-test */