ctlib: Reduce possible reentrance issues for res_type_str

freddy77 · freddy77 · commit 6a91414b2a75 · 2025-11-30T19:14:59.000Z
Change output buffer instead of always use the same one.
Not solving all possible issues but fine for test code.

Signed-off-by: Frediano Ziglio &lt;freddy77@gmail.com&gt;
diff --git a/src/ctlib/unittests/common.c b/src/ctlib/unittests/common.c
@@ -384,7 +384,9 @@ servermsg_cb(CS_CONTEXT * context TDS_UNUSED, CS_CONNECTION * connection TDS_UNU
 const char *
 res_type_str(CS_RETCODE ret)
 {
-	static char str[64];
+	static char str[4][32];
+	static uint8_t last_used;
+	uint8_t n;
 
 #define S(s) case s: return #s;
 	switch ((int) ret) {
@@ -399,8 +401,9 @@ res_type_str(CS_RETCODE ret)
 #undef S
 	}
 
-	sprintf(str, "?? (%d)", (int) ret);
-	return str;
+	n = (last_used++) & 3;
+	snprintf(str[n], sizeof(str[0]), "?? (%d)", (int) ret);
+	return str[n];
 }
 
 void

Original file line number	Diff line number	Diff line change
`@@ -384,7 +384,9 @@ servermsg_cb(CS_CONTEXT * context TDS_UNUSED, CS_CONNECTION * connection TDS_UNU`
`384`	`384`	`const char *`
`385`	`385`	`res_type_str(CS_RETCODE ret)`
`386`	`386`	`{`
`387`		`- static char str[64];`
	`387`	`+ static char str[4][32];`
	`388`	`+ static uint8_t last_used;`
	`389`	`+ uint8_t n;`
`388`	`390`
`389`	`391`	`#define S(s) case s: return #s;`
`390`	`392`	`switch ((int) ret) {`
`@@ -399,8 +401,9 @@ res_type_str(CS_RETCODE ret)`
`399`	`401`	`#undef S`
`400`	`402`	`}`
`401`	`403`
`402`		`- sprintf(str, "?? (%d)", (int) ret);`
`403`		`- return str;`
	`404`	`+ n = (last_used++) & 3;`
	`405`	`+ snprintf(str[n], sizeof(str[0]), "?? (%d)", (int) ret);`
	`406`	`+ return str[n];`
`404`	`407`	`}`
`405`	`408`
`406`	`409`	`void`