Fix: filter interpreter early-exits on uninitialized value

[deliverable/lttng-modules.git] / src / lttng-bytecode-interpreter.c

diff --git a/src/lttng-bytecode-interpreter.c b/src/lttng-bytecode-interpreter.c
index 950c0ba028fcc6ac619f27023ec9fb7dcf549d8f..153aeee656190330e34ce582b434b51a24883b99 100644 (file)
--- a/src/lttng-bytecode-interpreter.c
+++ b/src/lttng-bytecode-interpreter.c
@@ -20,7 +20,7 @@
  * to handle user-space read.
  */
 static
-char get_char(struct estack_entry *reg, size_t offset)
+char get_char(const struct estack_entry *reg, size_t offset)
 {
        if (unlikely(offset >= reg->u.s.seq_len))
                return '\0';
@@ -214,6 +214,14 @@ uint64_t lttng_bytecode_filter_interpret_false(void *filter_data,
        return LTTNG_INTERPRETER_DISCARD;
 }
 
+uint64_t lttng_bytecode_capture_interpret_false(void *filter_data,
+               struct lttng_probe_ctx *lttng_probe_ctx,
+               const char *capture_stack_data,
+               struct lttng_interpreter_output *output)
+{
+       return LTTNG_INTERPRETER_DISCARD;
+}
+
 #ifdef INTERPRETER_USE_SWITCH
 
 /*
@@ -298,11 +306,11 @@ static int context_get_index(struct lttng_probe_ctx *lttng_probe_ctx,
 
                ctx_field->get_value(ctx_field, lttng_probe_ctx, &v);
                if (itype->signedness) {
-                       ptr->object_type = OBJECT_TYPE_S64;
+                       ptr->object_type = OBJECT_TYPE_SIGNED_ENUM;
                        ptr->u.s64 = v.s64;
                        ptr->ptr = &ptr->u.s64;
                } else {
-                       ptr->object_type = OBJECT_TYPE_U64;
+                       ptr->object_type = OBJECT_TYPE_UNSIGNED_ENUM;
                        ptr->u.u64 = v.s64;     /* Cast. */
                        ptr->ptr = &ptr->u.u64;
                }
@@ -496,6 +504,18 @@ static int dynamic_load_field(struct estack_entry *stack_top)
                stack_top->type = REG_S64;
                break;
        }
+       case OBJECT_TYPE_SIGNED_ENUM:
+       {
+               int64_t tmp;
+
+               dbg_printk("op load field signed enumeration\n");
+               tmp = *(int64_t *) stack_top->u.ptr.ptr;
+               if (stack_top->u.ptr.rev_bo)
+                       __swab64s(&tmp);
+               stack_top->u.v = tmp;
+               stack_top->type = REG_S64;
+               break;
+       }
        case OBJECT_TYPE_U8:
                dbg_printk("op load field u8\n");
                stack_top->u.v = *(uint8_t *) stack_top->u.ptr.ptr;
@@ -537,6 +557,18 @@ static int dynamic_load_field(struct estack_entry *stack_top)
                stack_top->type = REG_U64;
                break;
        }
+       case OBJECT_TYPE_UNSIGNED_ENUM:
+       {
+               uint64_t tmp;
+
+               dbg_printk("op load field unsigned enumeration\n");
+               tmp = *(uint64_t *) stack_top->u.ptr.ptr;
+               if (stack_top->u.ptr.rev_bo)
+                       __swab64s(&tmp);
+               stack_top->u.v = tmp;
+               stack_top->type = REG_U64;
+               break;
+       }
        case OBJECT_TYPE_STRING:
        {
                const char *str;
@@ -649,6 +681,20 @@ again:
                        output->u.sequence.nr_elem = ax->u.ptr.field->type.u.array_nestable.length;
                        output->u.sequence.nested_type = ax->u.ptr.field->type.u.array_nestable.elem_type;
                        break;
+               case OBJECT_TYPE_SIGNED_ENUM:
+                       ret = dynamic_load_field(ax);
+                       if (ret)
+                               return ret;
+                       output->type = LTTNG_INTERPRETER_TYPE_SIGNED_ENUM;
+                       output->u.s = ax->u.v;
+                       break;
+               case OBJECT_TYPE_UNSIGNED_ENUM:
+                       ret = dynamic_load_field(ax);
+                       if (ret)
+                               return ret;
+                       output->type = LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM;
+                       output->u.u = ax->u.v;
+                       break;
                case OBJECT_TYPE_STRUCT:
                case OBJECT_TYPE_VARIANT:
                default:
@@ -665,6 +711,39 @@ again:
        return LTTNG_INTERPRETER_RECORD_FLAG;
 }
 
+#ifdef DEBUG
+
+#define DBG_USER_STR_CUTOFF 32
+
+/*
+ * In debug mode, print user string (truncated, if necessary).
+ */
+static inline
+void dbg_load_ref_user_str_printk(const struct estack_entry *user_str_reg)
+{
+       size_t pos = 0;
+       char last_char;
+       char user_str[DBG_USER_STR_CUTOFF];
+
+       pagefault_disable();
+       do {
+               last_char = get_char(user_str_reg, pos);
+               user_str[pos] = last_char;
+               pos++;
+       } while (last_char != '\0' && pos < sizeof(user_str));
+       pagefault_enable();
+
+       user_str[sizeof(user_str) - 1] = '\0';
+       dbg_printk("load field ref user string: '%s%s'\n", user_str,
+               last_char != '\0' ? "[...]" : "");
+}
+#else
+static inline
+void dbg_load_ref_user_str_printk(const struct estack_entry *user_str_reg)
+{
+}
+#endif
+
 /*
  * Return 0 (discard), or raise the 0x1 flag (log event).
  * Currently, other flags are kept for future extensions and have no
@@ -1458,7 +1537,7 @@ uint64_t bytecode_interpret(void *interpreter_data,
                        estack_push(stack, top, ax, bx, ax_t, bx_t);
                        estack_ax(stack, top)->u.s.user_str =
                                *(const char * const *) &interpreter_stack_data[ref->offset];
-                       if (unlikely(!estack_ax(stack, top)->u.s.str)) {
+                       if (unlikely(!estack_ax(stack, top)->u.s.user_str)) {
                                dbg_printk("Bytecode warning: loading a NULL string.\n");
                                ret = -EINVAL;
                                goto end;
@@ -1468,7 +1547,7 @@ uint64_t bytecode_interpret(void *interpreter_data,
                                ESTACK_STRING_LITERAL_TYPE_NONE;
                        estack_ax(stack, top)->u.s.user = 1;
                        estack_ax(stack, top)->type = REG_STRING;
-                       dbg_printk("ref load string %s\n", estack_ax(stack, top)->u.s.str);
+                       dbg_load_ref_user_str_printk(estack_ax(stack, top));
                        next_pc += sizeof(struct load_op) + sizeof(struct field_ref);
                        PO;
                }
@@ -1486,7 +1565,7 @@ uint64_t bytecode_interpret(void *interpreter_data,
                        estack_ax(stack, top)->u.s.user_str =
                                *(const char **) (&interpreter_stack_data[ref->offset
                                                                + sizeof(unsigned long)]);
-                       if (unlikely(!estack_ax(stack, top)->u.s.str)) {
+                       if (unlikely(!estack_ax(stack, top)->u.s.user_str)) {
                                dbg_printk("Bytecode warning: loading a NULL sequence.\n");
                                ret = -EINVAL;
                                goto end;
@@ -1744,6 +1823,15 @@ uint64_t lttng_bytecode_filter_interpret(void *filter_data,
                        filter_stack_data, NULL);
 }
 
+uint64_t lttng_bytecode_capture_interpret(void *capture_data,
+               struct lttng_probe_ctx *lttng_probe_ctx,
+               const char *capture_stack_data,
+               struct lttng_interpreter_output *output)
+{
+       return bytecode_interpret(capture_data, lttng_probe_ctx,
+                       capture_stack_data, output);
+}
+
 #undef START_OP
 #undef OP
 #undef PO