Fix: translate-trace-ir-to-ctf-ir.c: dereference after `NULL` check

We only need to call must_protect_variant_option_name() when the tag
field class is not created by the component (`fc->tag_is_before`).

Furthermore, the local `must_protect` variable is not used, so the
corresponding must_protect_variant_option_name() parameter is not
either. They are both removed. Because the
must_protect_variant_option_name() function actually sets the name of
the option to use (protecting it or not), it's renamed to
maybe_protect_variant_option_name().

Found by Coverity Scan.

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Change-Id: Ieccc0bcddc5570f473d4303f7cc470a56af65a9e

diff --git a/src/plugins/ctf/fs-sink/translate-trace-ir-to-ctf-ir.c b/src/plugins/ctf/fs-sink/translate-trace-ir-to-ctf-ir.c
index be00d041f4b067419dd37ee2f2ea14c9e3449023..30f4552ef4a681da7e0402563d47c79ccb786f51 100644 (file)
--- a/src/plugins/ctf/fs-sink/translate-trace-ir-to-ctf-ir.c
+++ b/src/plugins/ctf/fs-sink/translate-trace-ir-to-ctf-ir.c
@@ -709,8 +709,10 @@ end:
 }
 
 /*
- * This function indicates whether or not a given variant FC option name
- * must be protected (with the `_` prefix).
+ * This function protects a given variant FC option name (with the `_`
+ * prefix) if required. On success, `name_buf->str` contains the variant
+ * FC option name to use (original option name or protected if
+ * required).
  *
  * One of the goals of `sink.ctf.fs` is to write a CTF trace which is as
  * close as possible to an original CTF trace as decoded by
@@ -776,9 +778,9 @@ end:
  * FC options and enumeration FC mappings by range set.
  */
 static
-int must_protect_variant_option_name(const bt_field_class *ir_var_fc,
+int maybe_protect_variant_option_name(const bt_field_class *ir_var_fc,
                const bt_field_class *ir_tag_fc, uint64_t opt_i,
-               GString *name_buf, bool *must_protect)
+               GString *name_buf)
 {
        int ret = 0;
        uint64_t i;
@@ -789,7 +791,6 @@ int must_protect_variant_option_name(const bt_field_class *ir_var_fc,
        const bt_field_class_variant_option *base_var_opt;
        bool force_protect = false;
 
-       *must_protect = false;
        ir_var_fc_type = bt_field_class_get_type(ir_var_fc);
        base_var_opt = bt_field_class_variant_borrow_option_by_index_const(
                ir_var_fc, opt_i);
@@ -805,7 +806,6 @@ int must_protect_variant_option_name(const bt_field_class *ir_var_fc,
         */
        force_protect = must_protect_identifier(ir_opt_name);
        if (force_protect) {
-               *must_protect = true;
                g_string_assign(name_buf, "_");
                g_string_append(name_buf, ir_opt_name);
        } else {
@@ -909,13 +909,6 @@ int must_protect_variant_option_name(const bt_field_class *ir_var_fc,
                        ret = -1;
                        goto end;
                }
-
-               /*
-                * If this comes from a `src.ctf.fs` source, it looks
-                * like the variant FC option name was initially
-                * protected: protect it again when going back to TSDL.
-                */
-               *must_protect = true;
        }
 
 end:
@@ -970,7 +963,7 @@ int translate_variant_field_class(struct ctx *ctx)
                }
 
                /*
-                * Call must_protect_variant_option_name() for each
+                * Call maybe_protect_variant_option_name() for each
                 * option below. In that case we also want selector FC
                 * to contain as many mappings as the variant FC has
                 * options.
@@ -990,6 +983,7 @@ int translate_variant_field_class(struct ctx *ctx)
                 * create the appropriate selector field class.
                 */
                fc->tag_is_before = true;
+               goto validate_opts;
        }
 
 validate_opts:
@@ -1004,12 +998,13 @@ validate_opts:
         * cur_path_stack_push().
         */
        for (i = 0; i < opt_count; i++) {
-               bool must_protect = false;
-
-               ret = must_protect_variant_option_name(fc->base.ir_fc,
-                       tgt_fc->ir_fc, i, name_buf, &must_protect);
-               if (ret) {
-                       fc->tag_is_before = true;
+               if (!fc->tag_is_before) {
+                       BT_ASSERT(tgt_fc->ir_fc);
+                       ret = maybe_protect_variant_option_name(fc->base.ir_fc,
+                               tgt_fc->ir_fc, i, name_buf);
+                       if (ret) {
+                               fc->tag_is_before = true;
+                       }
                }
 
                ret = bt_value_array_append_string_element(prot_opt_names,