fiber: introduce fiber_set_name_n function

NO_DOC=picodata internal patch
NO_CHANGELOG=picodata internal patch
NO_TEST=picodata internal patch

src/lib/core/fiber.c

@@ -1039,10 +1039,16 @@ fiber_loop(MAYBE_UNUSED void *data)
 	}
 }
 
-void
+inline void
 fiber_set_name(struct fiber *fiber, const char *name)
 {
-	size_t size = strlen(name) + 1;
+	fiber_set_name_n(fiber, name, strlen(name));
+}
+
+void
+fiber_set_name_n(struct fiber *fiber, const char *name, uint32_t len)
+{
+	size_t size = len + 1;
 	if (size <= FIBER_NAME_INLINE) {
 		if (fiber->name != fiber->inline_name) {
 			free(fiber->name);

src/lib/core/fiber.h

@@ -949,6 +949,15 @@ fiber_signal_reset(void);
 void
 fiber_set_name(struct fiber *fiber, const char *name);
 
+/**
+ * Set fiber name providing a length for it.
+ * @param fiber Fiber to set name for.
+ * @param name A new name of @a fiber.
+ * @param len Length of the string pointed to by @a name.
+ */
+void
+fiber_set_name_n(struct fiber *fiber, const char *name, uint32_t len);
+
 static inline const char *
 fiber_name(struct fiber *f)
 {

test/unit/fiber.cc

@@ -253,6 +253,19 @@ fiber_name_test()
 	fiber_set_name(fiber(), long_name);
 
 	note("fiber name is truncated: %s.\n", fiber_name(fiber()));
+
+	fiber_set_name_n(fiber(), long_name, 10);
+	note("set fiber name with given length: %s.\n", fiber_name(fiber()));
+
+	fiber_set_name_n(fiber(), long_name, 0);
+	note("set fiber name with 0 length: %s.\n", fiber_name(fiber()));
+
+	const int n = 3;
+	fiber_set_name_n(fiber(), "a\0b", n);
+	note("set fiber name with a nul byte in it (don't do that): %s.\n",
+	     fiber_name(fiber()));
+	fail_unless(memcmp(fiber_name(fiber()), "a\0b", n) == 0);
+
 	footer();
 }
 

test/unit/fiber.result

@@ -7,6 +7,12 @@ OutOfMemory: Failed to allocate 42 bytes in allocator for exception
 
 # fiber name is truncated: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.
 
+# set fiber name with given length: aaaaaaaaaa.
+
+# set fiber name with 0 length: .
+
+# set fiber name with a nul byte in it (don't do that): a.
+
 	*** fiber_name_test: done ***
 	*** fiber_join_test ***
 # exception propagated