diff mbox series

[net-next,v4,2/8] selftests/net: Provide test_snprintf() helper

Message ID 20240823-tcp-ao-selftests-upd-6-12-v4-2-05623636fe8c@gmail.com (mailing list archive)
State Accepted
Commit 7053e788ded5f8ec589e4507d764d6a894780d6c
Delegated to: Netdev Maintainers
Headers show
Series net/selftests: TCP-AO selftests updates | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline fail Detected static functions without inline keyword in header files: 1
netdev/build_32bit success Errors and warnings before: 7 this patch: 7
netdev/build_tools success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers success CCed 7 of 7 maintainers
netdev/build_clang success Errors and warnings before: 7 this patch: 7
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 7 this patch: 7
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 68 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-08-25--21-00 (tests: 714)

Commit Message

Dmitry Safonov via B4 Relay Aug. 23, 2024, 10:04 p.m. UTC 
From: Dmitry Safonov <0x7f454c46@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 <0x7f454c46@gmail.com>
---
 tools/testing/selftests/net/tcp_ao/lib/aolib.h | 59 ++++++++++++++++++++++----
 1 file changed, 50 insertions(+), 9 deletions(-)
diff mbox series

Patch

diff --git a/tools/testing/selftests/net/tcp_ao/lib/aolib.h b/tools/testing/selftests/net/tcp_ao/lib/aolib.h
index fbc7f6111815..78466863435f 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 = n + 1;
+	ret = malloc(size);
+	if (!ret)
+		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, ...)						\