Fix: overflow of signed integer results in undefined behaviour

[babeltrace.git] / formats / ctf / ir / clock.c

diff --git a/formats/ctf/ir/clock.c b/formats/ctf/ir/clock.c
index 0bf7f3518cd5026450703001190699bd031be717..9256bc1f26f58ef5cb4f04a8ca9a92d32dc364e7 100644 (file)
--- a/formats/ctf/ir/clock.c
+++ b/formats/ctf/ir/clock.c
@@ -99,6 +99,13 @@ struct bt_ctf_clock *bt_ctf_clock_create(const char *name)
                goto error;
        }
 
+       /*
+        * For backward compatibility reasons, a fresh clock can have
+        * a value because it could be added to a trace created by a
+        * CTF writer. As soon as this clock is added to a non-writer
+        * trace, then its value/time functions will be disabled.
+        */
+       clock->has_value = 1;
        clock->uuid_set = 1;
        return clock;
 error:
@@ -318,6 +325,19 @@ end:
        return ret;
 }
 
+uint64_t ns_from_value(uint64_t frequency, uint64_t value)
+{
+       uint64_t ns;
+
+       if (frequency == 1000000000) {
+               ns = value;
+       } else {
+               ns = (uint64_t) ((1e9 * (double) value) / (double) frequency);
+       }
+
+       return ns;
+}
+
 int bt_ctf_clock_get_time(struct bt_ctf_clock *clock, int64_t *time)
 {
        int ret = 0;
@@ -327,14 +347,17 @@ int bt_ctf_clock_get_time(struct bt_ctf_clock *clock, int64_t *time)
                goto end;
        }
 
-       /* Common case where cycles are actually nanoseconds */
-       if (clock->frequency == 1000000000) {
-               *time = (int64_t) clock->value;
-       } else {
-               *time = (int64_t) ((1e9 * (double) clock->value) /
-                       (double) clock->frequency);
+
+       if (!clock->has_value) {
+               /*
+                * Clock belongs to a non-writer mode trace and thus
+                * this function is disabled.
+                */
+               goto end;
        }
 
+       *time = (int64_t) ns_from_value(clock->frequency, clock->value);
+
 end:
        return ret;
 }
@@ -342,6 +365,7 @@ end:
 int bt_ctf_clock_set_time(struct bt_ctf_clock *clock, int64_t time)
 {
        int ret = 0;
+       int64_t value;
 
        /* Timestamps are strictly monotonic */
        if (!clock) {
@@ -349,15 +373,25 @@ int bt_ctf_clock_set_time(struct bt_ctf_clock *clock, int64_t time)
                goto end;
        }
 
-       /* Common case where cycles are actually nanoseconds */
-       if (clock->frequency == 1000000000) {
-               clock->value = time;
+
+       if (!clock->has_value) {
+               /*
+                * Clock belongs to a non-writer mode trace and thus
+                * this function is disabled.
+                */
+               ret = -1;
                goto end;
        }
 
-       ret = bt_ctf_clock_set_value(clock,
-               (uint64_t) (((double) time * (double) clock->frequency) / 1e9));
+       /* Common case where cycles are actually nanoseconds */
+       if (clock->frequency == 1000000000) {
+               value = time;
+       } else {
+               value = (uint64_t) (((double) time *
+                       (double) clock->frequency) / 1e9);
+       }
 
+       ret = bt_ctf_clock_set_value(clock, value);
 end:
        return ret;
 }
@@ -370,6 +404,14 @@ uint64_t bt_ctf_clock_get_value(struct bt_ctf_clock *clock)
                goto end;
        }
 
+       if (!clock->has_value) {
+               /*
+                * Clock belongs to a non-writer mode trace and thus
+                * this function is disabled.
+                */
+               goto end;
+       }
+
        ret = clock->value;
 end:
        return ret;
@@ -379,8 +421,22 @@ int bt_ctf_clock_set_value(struct bt_ctf_clock *clock, uint64_t value)
 {
        int ret = 0;
 
+       if (!clock) {
+               ret = -1;
+               goto end;
+       }
+
+       if (!clock->has_value) {
+               /*
+                * Clock belongs to a non-writer mode trace and thus
+                * this function is disabled.
+                */
+               ret = -1;
+               goto end;
+       }
+
        /* Timestamps are strictly monotonic */
-       if (!clock || value < clock->value) {
+       if (value < clock->value) {
                ret = -1;
                goto end;
        }
@@ -464,3 +520,24 @@ void bt_ctf_clock_destroy(struct bt_object *obj)
 
        g_free(clock);
 }
+
+int64_t bt_ctf_clock_ns_from_value(struct bt_ctf_clock *clock, uint64_t value)
+{
+       int64_t ns = -1ULL;
+
+       if (!clock) {
+               goto end;
+       }
+
+       /* Initialize nanosecond timestamp to clock's offset in seconds */
+       ns = clock->offset_s * 1000000000;
+
+       /* Add offset in cycles, converted to nanoseconds */
+       ns += ns_from_value(clock->frequency, clock->offset);
+
+       /* Add given value, converter to nanoseconds */
+       ns += ns_from_value(clock->frequency, value);
+
+end:
+       return ns;
+}