[kvm-unit-tests PATCH 21/32] lib: printf-style report prefixes

[David Matlack <dmatlack@xxxxxxxxxx>]

From: Peter Feiner <pfeiner@xxxxxxxxxx>

Signed-off-by: Peter Feiner <pfeiner@xxxxxxxxxx>
Signed-off-by: David Matlack <dmatlack@xxxxxxxxxx>
---
 lib/libcflat.h |  1 +
 lib/report.c   | 38 +++++++++++++++++++++++++++++++++-----
 2 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/lib/libcflat.h b/lib/libcflat.h
index 5d356df75f1f..05c18543dd72 100644
--- a/lib/libcflat.h
+++ b/lib/libcflat.h
@@ -96,6 +96,7 @@ extern int vsnprintf(char *buf, int size, const char *fmt, va_list va)
 extern int vprintf(const char *fmt, va_list va)
 					__attribute__((format(printf, 1, 0)));
 
+void report_prefix_pushf(const char *prefix_fmt, ...);
 extern void report_prefix_push(const char *prefix);
 extern void report_prefix_pop(void);
 extern void report(const char *msg_fmt, bool pass, ...);
diff --git a/lib/report.c b/lib/report.c
index e24e81382f9e..1033f1e44e99 100644
--- a/lib/report.c
+++ b/lib/report.c
@@ -17,14 +17,42 @@ static unsigned int tests, failures, xfailures, skipped;
 static char prefixes[256];
 static struct spinlock lock;
 
-void report_prefix_push(const char *prefix)
+#define PREFIX_DELIMITER ": "
+
+void report_prefix_pushf(const char *prefix_fmt, ...)
 {
+	va_list va;
+	int len;
+	int start;
+
 	spin_lock(&lock);
-	strcat(prefixes, prefix);
-	strcat(prefixes, ": ");
+
+	len = strlen(prefixes);
+	assert_msg(len < sizeof(prefixes), "%d >= %lu", len, sizeof(prefixes));
+	start = len;
+
+	va_start(va, prefix_fmt);
+	len += vsnprintf(&prefixes[len], sizeof(prefixes) - len, prefix_fmt,
+			 va);
+	va_end(va);
+	assert_msg(len < sizeof(prefixes), "%d >= %lu", len, sizeof(prefixes));
+
+	assert_msg(!strstr(&prefixes[start], PREFIX_DELIMITER),
+		   "Prefix \"%s\" contains delimiter \"" PREFIX_DELIMITER "\"",
+		   &prefixes[start]);
+
+	len += snprintf(&prefixes[len], sizeof(prefixes) - len,
+			PREFIX_DELIMITER);
+	assert_msg(len < sizeof(prefixes), "%d >= %lu", len, sizeof(prefixes));
+
 	spin_unlock(&lock);
 }
 
+void report_prefix_push(const char *prefix)
+{
+	report_prefix_pushf("%s", prefix);
+}
+
 void report_prefix_pop(void)
 {
 	char *p, *q;
@@ -34,9 +62,9 @@ void report_prefix_pop(void)
 	if (!*prefixes)
 		return;
 
-	for (p = prefixes, q = strstr(p, ": ") + 2;
+	for (p = prefixes, q = strstr(p, PREFIX_DELIMITER) + 2;
 			*q;
-			p = q, q = strstr(p, ": ") + 2)
+			p = q, q = strstr(p, PREFIX_DELIMITER) + 2)
 		;
 	*p = '\0';
 
-- 
2.12.2.816.g2cccc81164-goog