Add targeted SQL read fault injection for poll command tests

tests/Makefile.am

@@ -1320,6 +1320,8 @@ test_tcp_io_flush_LDADD = $(LIBUTUN) $(CRYPTO_LIBS) $(COMMON_LIBS)
 test_chat_poll_SOURCES = test_chat_poll.c
 test_chat_poll_CFLAGS = -I$(top_srcdir)/src -I$(top_srcdir)/src/chat -I$(top_srcdir)/lib
 test_chat_poll_LDADD = $(LIBUTUN) $(CRYPTO_LIBS) $(COMMON_LIBS)
+test_chat_poll_LDFLAGS = -Wl,--wrap=sqlite3_prepare_v2 -Wl,--wrap=sqlite3_bind_blob -Wl,--wrap=sqlite3_bind_text \
+    -Wl,--wrap=sqlite3_step -Wl,--wrap=sqlite3_finalize
 
 test_chat_poll_network_SOURCES = test_chat_poll_network.c
 test_chat_poll_network_CFLAGS = -I$(top_srcdir)/src -I$(top_srcdir)/src/chat -I$(top_srcdir)/lib

tests/test_chat_poll.c

@@ -5,6 +5,66 @@
 #include "../src/config_parser.h"
 #include <assert.h>
 
+enum poll_fault { P_NONE, P_PREPARE, P_BIND, P_STEP, P_FINALIZE };
+enum poll_query { P_VALID, P_FIELD, P_TARGET, P_SNAPSHOT, P_CHOICES, P_OPTIONS };
+static enum poll_fault fault;
+static enum poll_query query;
+static unsigned query_number, matching_queries, fault_bind, changed_events;
+static sqlite3_stmt* fault_statement;
+
+static int query_matches(const char* sql) {
+    const char* prefix[] = {"SELECT json_valid(?1)", "SELECT json_type(?1,?2),json_extract(?1,?2)",
+        "SELECT CASE WHEN json_valid", "SELECT node_id,kind,ver,data FROM feedback_",
+        "SELECT type,value FROM json_each(?1,?2)", "SELECT type,value FROM json_each(?1,'$.options')"};
+    return !strncmp(sql, prefix[query], strlen(prefix[query]));
+}
+
+static int take_fault(enum poll_fault point, sqlite3_stmt* st, unsigned index) {
+    if (fault != point || st != fault_statement || (point == P_BIND && index != fault_bind)) return 0;
+    fault = P_NONE;
+    DEBUG_WARN(DEBUG_CATEGORY_CHAT_SYNC, "poll test: injected query=%d occurrence=%u stage=%d bind=%u", query, query_number, point, index);
+    return 1;
+}
+
+extern int __real_sqlite3_prepare_v2(sqlite3*, const char*, int, sqlite3_stmt**, const char**);
+int __wrap_sqlite3_prepare_v2(sqlite3* db, const char* sql, int length, sqlite3_stmt** st, const char** tail) {
+    int target = fault != P_NONE && query_matches(sql) && ++matching_queries == query_number;
+    if (target && fault == P_PREPARE) {
+        fault = P_NONE; *st = NULL; DEBUG_WARN(DEBUG_CATEGORY_CHAT_SYNC, "poll test: prepare query=%d occurrence=%u", query, query_number);
+        return SQLITE_NOMEM;
+    }
+    int rc = __real_sqlite3_prepare_v2(db, sql, length, st, tail);
+    if (target && rc == SQLITE_OK) fault_statement = *st;
+    return rc;
+}
+extern int __real_sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int, void (*)(void*));
+int __wrap_sqlite3_bind_blob(sqlite3_stmt* st, int index, const void* bytes, int length, void (*destroy)(void*)) {
+    if (take_fault(P_BIND, st, index)) return SQLITE_NOMEM;
+    return __real_sqlite3_bind_blob(st, index, bytes, length, destroy);
+}
+extern int __real_sqlite3_bind_text(sqlite3_stmt*, int, const char*, int, void (*)(void*));
+int __wrap_sqlite3_bind_text(sqlite3_stmt* st, int index, const char* bytes, int length, void (*destroy)(void*)) {
+    if (take_fault(P_BIND, st, index)) return SQLITE_NOMEM;
+    return __real_sqlite3_bind_text(st, index, bytes, length, destroy);
+}
+extern int __real_sqlite3_step(sqlite3_stmt*);
+int __wrap_sqlite3_step(sqlite3_stmt* st) {
+    if (take_fault(P_STEP, st, 0)) return SQLITE_IOERR;
+    return __real_sqlite3_step(st);
+}
+extern int __real_sqlite3_finalize(sqlite3_stmt*);
+int __wrap_sqlite3_finalize(sqlite3_stmt* st) {
+    int fail = st && take_fault(P_FINALIZE, st, 0);
+    int rc = __real_sqlite3_finalize(st); if (st == fault_statement) fault_statement = NULL;
+    return fail ? SQLITE_IOERR : rc;
+}
+
+static void poll_event(struct UTUN_INSTANCE* inst, int type, const uint8_t* data, int len) {
+    (void)data; (void)len;
+    assert(sqlite3_get_autocommit(inst->topo_sqlite_db));
+    if (type == CHAT_EVT_FEEDBACK_CHANGED || type == CHAT_EVT_MSG_RECEIVED) changed_events++;
+}
+
 static sqlite3_int64 json_number(sqlite3* db, const char* json, const char* path) {
     sqlite3_stmt* st = NULL;
     assert(sqlite3_prepare_v2(db, "SELECT json_extract(?1,?2)", -1, &st, NULL) == SQLITE_OK);