add osmo_fsm_inst_update_id_f()

In the osmo-msc, I would like to set the subscr conn FSM identifier by a string
format, to include the type of Complete Layer 3 that is taking place. I could
each time talloc a string and free it again. This API is more convenient.

From osmo_fsm_inst_update_id(), call osmo_fsm_inst_update_id_f() with "%s" (or
pass NULL).

Put the name updating into separate static update_name() function to clarify.

Adjust the error message for erratic ID: don't say "allocate", it might be from
an update. Adjust test expectation.

Change-Id: I76743a7642f2449fd33350691ac8ebbf4400371d

4 files changed, 97 insertions, 22 deletions

diff --git a/include/osmocom/core/fsm.h b/include/osmocom/core/fsm.h
index 2c2a9961..174396a7 100644
--- a/include/osmocom/core/fsm.h
+++ b/include/osmocom/core/fsm.h
@@ -159,6 +159,7 @@ void osmo_fsm_inst_change_parent(struct osmo_fsm_inst *fi,
 void osmo_fsm_inst_free(struct osmo_fsm_inst *fi);
 
 int osmo_fsm_inst_update_id(struct osmo_fsm_inst *fi, const char *id);
+int osmo_fsm_inst_update_id_f(struct osmo_fsm_inst *fi, const char *fmt, ...);
 
 const char *osmo_fsm_event_name(struct osmo_fsm *fsm, uint32_t event);
 const char *osmo_fsm_inst_name(struct osmo_fsm_inst *fi);
diff --git a/src/fsm.c b/src/fsm.c
index 0fdc564d..ae2fdc2a 100644
--- a/src/fsm.c
+++ b/src/fsm.c
@@ -211,38 +211,61 @@ static void fsm_tmr_cb(void *data)
  */
 int osmo_fsm_inst_update_id(struct osmo_fsm_inst *fi, const char *id)
 {
-	if (id) {
+	if (!id)
+		return osmo_fsm_inst_update_id_f(fi, NULL);
+	else
+		return osmo_fsm_inst_update_id_f(fi, "%s", id);
+}
+
+static void update_name(struct osmo_fsm_inst *fi)
+{
+	if (fi->name)
+		talloc_free((char*)fi->name);
+
+	if (!fsm_log_addr) {
+		if (fi->id)
+			fi->name = talloc_asprintf(fi, "%s(%s)", fi->fsm->name, fi->id);
+		else
+			fi->name = talloc_asprintf(fi, "%s", fi->fsm->name);
+	} else {
+		if (fi->id)
+			fi->name = talloc_asprintf(fi, "%s(%s)[%p]", fi->fsm->name, fi->id, fi);
+		else
+			fi->name = talloc_asprintf(fi, "%s[%p]", fi->fsm->name, fi);
+	}
+}
+
+/*! Change id of the FSM instance using a string format.
+ * \param[in] fi FSM instance.
+ * \param[in] fmt format string to compose new ID.
+ * \param[in] ... variable argument list for format string.
+ * \returns 0 if the ID was updated, otherwise -EINVAL.
+ */
+int osmo_fsm_inst_update_id_f(struct osmo_fsm_inst *fi, const char *fmt, ...)
+{
+	char *id = NULL;
+
+	if (fmt) {
+		va_list ap;
+
+		va_start(ap, fmt);
+		id = talloc_vasprintf(fi, fmt, ap);
+		va_end(ap);
+
 		if (!osmo_identifier_valid(id)) {
 			LOGP(DLGLOBAL, LOGL_ERROR,
 			     "Attempting to set illegal id for FSM instance of type '%s': %s\n",
 			     fi->fsm->name, osmo_quote_str(id, -1));
+			talloc_free(id);
 			return -EINVAL;
 		}
-		osmo_talloc_replace_string(fi, (char **)&fi->id, id);
-
-		if (fi->name)
-			talloc_free((void*)fi->name);
-
-		if (!fsm_log_addr) {
-			fi->name = talloc_asprintf(fi, "%s(%s)", fi->fsm->name, id);
-		} else {
-			fi->name = talloc_asprintf(fi, "%s(%s)[%p]", fi->fsm->name, id, fi);
-		}
-
-		return 0;
 	}
 
 	if (fi->id)
-		talloc_free((void*)fi->id);
-	fi->id = NULL;
-	if (fi->name)
-		talloc_free((void*)fi->name);
+		talloc_free((char*)fi->id);
+	fi->id = id;
 
-	if (!fsm_log_addr) {
-		fi->name = talloc_asprintf(fi, "%s", fi->fsm->name);
-	} else {
-		fi->name = talloc_asprintf(fi, "%s[%p]", fi->fsm->name, fi);
-	}
+	update_name(fi);
 	return 0;
 }
 
diff --git a/tests/fsm/fsm_test.c b/tests/fsm/fsm_test.c
index 859b78dc..e34164cf 100644
--- a/tests/fsm/fsm_test.c
+++ b/tests/fsm/fsm_test.c
@@ -237,6 +237,30 @@ do { \
 
 	test_id("invalid.id", -EINVAL, "(arbitrary_id)");
 
+	fprintf(stderr, "--- id format tests...\n");
+/* Update the id, assert the proper rc, and expect a resulting fsm inst name + lookup */
+#define test_id_f(expect_rc, expect_name_suffix, new_id_fmt, args...) do { \
+		int rc; \
+		fprintf(stderr, "osmo_fsm_inst_update_id_f(%s, " #args ")\n", \
+			osmo_quote_str(new_id_fmt, -1)); \
+		rc = osmo_fsm_inst_update_id_f(fi, new_id_fmt, ## args); \
+		fprintf(stderr, "    rc == %d", rc); \
+		if (rc == (expect_rc)) \
+			fprintf(stderr, ", ok\n"); \
+		else { \
+			fprintf(stderr, ", ERROR: expected rc == %d\n", expect_rc); \
+			OSMO_ASSERT(rc == expect_rc); \
+		} \
+		assert_name("Test_FSM" expect_name_suffix); \
+	}while (0)
+
+	test_id_f(-EINVAL, "(arbitrary_id)", "format%cid", '.');
+	test_id_f(-EINVAL, "(arbitrary_id)", "%s", "");
+	test_id_f(0, "(format23id42)", "format%xid%d", 0x23, 42);
+	test_id_f(0, "", NULL);
+	test_id_f(0, "", NULL);
+	test_id_f(0, "(arbitrary_id)", "%s%c%s", "arbitrary", '_', "id");
+
 	fprintf(stderr, "\n--- %s() done\n\n", __func__);
 
 	osmo_fsm_inst_term(fi, OSMO_FSM_TERM_REQUEST, NULL);
diff --git a/tests/fsm/fsm_test.err b/tests/fsm/fsm_test.err
index 3e01d48b..3237def5 100644
--- a/tests/fsm/fsm_test.err
+++ b/tests/fsm/fsm_test.err
@@ -47,6 +47,33 @@ Attempting to set illegal id for FSM instance of type 'Test_FSM': "invalid.id"
     rc == -22, ok
   osmo_fsm_inst_name() == "Test_FSM(arbitrary_id)"
   osmo_fsm_inst_find_by_name("Test_FSM(arbitrary_id)") == fi
+--- id format tests...
+osmo_fsm_inst_update_id_f("format%cid", '.')
+Attempting to set illegal id for FSM instance of type 'Test_FSM': "format.id"
+    rc == -22, ok
+  osmo_fsm_inst_name() == "Test_FSM(arbitrary_id)"
+  osmo_fsm_inst_find_by_name("Test_FSM(arbitrary_id)") == fi
+osmo_fsm_inst_update_id_f("%s", "")
+Attempting to set illegal id for FSM instance of type 'Test_FSM': ""
+    rc == -22, ok
+  osmo_fsm_inst_name() == "Test_FSM(arbitrary_id)"
+  osmo_fsm_inst_find_by_name("Test_FSM(arbitrary_id)") == fi
+osmo_fsm_inst_update_id_f("format%xid%d", 0x23, 42)
+    rc == 0, ok
+  osmo_fsm_inst_name() == "Test_FSM(format23id42)"
+  osmo_fsm_inst_find_by_name("Test_FSM(format23id42)") == fi
+osmo_fsm_inst_update_id_f(NULL, )
+    rc == 0, ok
+  osmo_fsm_inst_name() == "Test_FSM"
+  osmo_fsm_inst_find_by_name("Test_FSM") == fi
+osmo_fsm_inst_update_id_f(NULL, )
+    rc == 0, ok
+  osmo_fsm_inst_name() == "Test_FSM"
+  osmo_fsm_inst_find_by_name("Test_FSM") == fi
+osmo_fsm_inst_update_id_f("%s%c%s", "arbitrary", '_', "id")
+    rc == 0, ok
+  osmo_fsm_inst_name() == "Test_FSM(arbitrary_id)"
+  osmo_fsm_inst_find_by_name("Test_FSM(arbitrary_id)") == fi
 
 --- test_id_api() done