From: Dmitry Safonov <0x7f454...@gmail.com>

Instead of pre-allocating a fixed-sized buffer of TEST_MSG_BUFFER_SIZE
and printing into it, call vsnprintf() with str = NULL, which will
return the needed size of the buffer. This hack is documented in
man 3 vsnprintf.

Essentially, in C++ terms, it re-invents std::stringstream, which is
going to be used to print different tracing paths and formatted strings.
Use it straight away in __test_print() - which is thread-safe version of
printing in selftests.

Signed-off-by: Dmitry Safonov <0x7f454...@gmail.com>
---
 tools/testing/selftests/net/tcp_ao/lib/aolib.h | 59 ++++++++++++++++++++++----
 1 file changed, 50 insertions(+), 9 deletions(-)

diff --git a/tools/testing/selftests/net/tcp_ao/lib/aolib.h 
b/tools/testing/selftests/net/tcp_ao/lib/aolib.h
index fbc7f6111815..60a63419cabb 100644
--- a/tools/testing/selftests/net/tcp_ao/lib/aolib.h
+++ b/tools/testing/selftests/net/tcp_ao/lib/aolib.h
@@ -37,17 +37,58 @@ extern void __test_xfail(const char *buf);
 extern void __test_error(const char *buf);
 extern void __test_skip(const char *buf);
 
-__attribute__((__format__(__printf__, 2, 3)))
-static inline void __test_print(void (*fn)(const char *), const char *fmt, ...)
+static inline char *test_snprintf(const char *fmt, va_list vargs)
 {
-#define TEST_MSG_BUFFER_SIZE 4096
-       char buf[TEST_MSG_BUFFER_SIZE];
-       va_list arg;
+       char *ret = NULL;
+       size_t size = 0;
+       va_list tmp;
+       int n = 0;
 
-       va_start(arg, fmt);
-       vsnprintf(buf, sizeof(buf), fmt, arg);
-       va_end(arg);
-       fn(buf);
+       va_copy(tmp, vargs);
+       n = vsnprintf(ret, size, fmt, tmp);
+       if (n < 0)
+               return NULL;
+
+       size = (size_t) n + 1;
+       ret = malloc(size);
+       if (ret == NULL)
+               return NULL;
+
+       n = vsnprintf(ret, size, fmt, vargs);
+       if (n < 0 || n > size - 1) {
+               free(ret);
+               return NULL;
+       }
+       return ret;
+}
+
+static __printf(1, 2) inline char *test_sprintf(const char *fmt, ...)
+{
+       va_list vargs;
+       char *ret;
+
+       va_start(vargs, fmt);
+       ret = test_snprintf(fmt, vargs);
+       va_end(vargs);
+
+       return ret;
+}
+
+static __printf(2, 3) inline void __test_print(void (*fn)(const char *),
+                                              const char *fmt, ...)
+{
+       va_list vargs;
+       char *msg;
+
+       va_start(vargs, fmt);
+       msg = test_snprintf(fmt, vargs);
+       va_end(vargs);
+
+       if (!msg)
+               return;
+
+       fn(msg);
+       free(msg);
 }
 
 #define test_print(fmt, ...)                                           \

-- 
2.42.2



Reply via email to