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tools/generate-wire.py: fix varsize assignment.

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Code like this is suspicious:

	subtype_varsize_struct->field_0 = *fromwire_test_features(subtype_varsize_struct, cursor, plen);

In fact, it is a memory leak since we copy and don't free the fromwire
result.  Really, field_0 should be a pointer.

We don't hit this case (yet!) in spec-generated code, but I did for
bolt13.

Here's the difference in gen_test output:

```patch
  diff -ur /tmp/before/test/gen_test.c /tmp/after/test/gen_test.c
  --- /tmp/before/test/gen_test.c	2020-05-07 16:23:31.651611235 +0930
  +++ /tmp/after/test/gen_test.c	2020-05-07 16:20:54.232574482 +0930
  @@ -214,12 +214,12 @@
   static void towire_subtype_varsize_struct(u8 **p, const struct subtype_varsize_struct *subtype_varsize_struct)
   {
   
  -	towire_test_features(p, &subtype_varsize_struct->field_0);
  +	towire_test_features(p, subtype_varsize_struct->field_0);
   }
   static void fromwire_subtype_varsize_struct(const u8 **cursor, size_t *plen, struct subtype_varsize_struct *subtype_varsize_struct)
   {
   
  - 	subtype_varsize_struct->field_0 = *fromwire_test_features(subtype_varsize_struct, cursor, plen);
  + 	subtype_varsize_struct->field_0 = fromwire_test_features(subtype_varsize_struct, cursor, plen);
   }
   
   /* SUBTYPE: SUBTYPE_VAR_LEN */
  @@ -373,7 +373,7 @@
   
   	ptr = tal_arr(ctx, u8, 0);
   
  -	towire_test_features(&ptr, &r->tlv3->features);
  +	towire_test_features(&ptr, r->tlv3->features);
   
   	towire_amount_msat(&ptr, r->tlv3->amount_msat_1);
   
  @@ -385,7 +385,7 @@
   	struct tlv_test_n1 *r = vrecord;
   
   	r->tlv3 = tal(r, struct tlv_test_n1_tlv3);
  -	r->tlv3->features = *fromwire_test_features(r->tlv3, cursor, plen);
  +	r->tlv3->features = fromwire_test_features(r->tlv3, cursor, plen);
   	r->tlv3->amount_msat_1 = fromwire_amount_msat(cursor, plen);
   	r->tlv3->amount_msat_2 = fromwire_amount_msat(cursor, plen);
   }
  @@ -824,11 +824,11 @@
   
   	towire_test_short_id(&ptr, &r->tlv3->subtype);
   
  -	towire_subtype_var_len(&ptr, &r->tlv3->varlen_subtype);
  +	towire_subtype_var_len(&ptr, r->tlv3->varlen_subtype);
   
  -	towire_subtype_var_assign(&ptr, &r->tlv3->varlen_assigned);
  +	towire_subtype_var_assign(&ptr, r->tlv3->varlen_assigned);
   
  -	towire_subtype_varlen_varsize(&ptr, &r->tlv3->test_sbt_varlen_varsize);
  +	towire_subtype_varlen_varsize(&ptr, r->tlv3->test_sbt_varlen_varsize);
   
   		for (size_t i = 0; i < 2; i++)
   		towire_u32(&ptr, r->tlv3->arr_assign[i]);
  @@ -868,9 +868,9 @@
   
   	r->tlv3 = tal(r, struct tlv_test_n3_tlv3);
   	fromwire_test_short_id(cursor, plen, &r->tlv3->subtype);
  -	r->tlv3->varlen_subtype = *fromwire_subtype_var_len(r->tlv3, cursor, plen);
  -	r->tlv3->varlen_assigned = *fromwire_subtype_var_assign(r->tlv3, cursor, plen);
  -	r->tlv3->test_sbt_varlen_varsize = *fromwire_subtype_varlen_varsize(r->tlv3, cursor, plen);
  +	r->tlv3->varlen_subtype = fromwire_subtype_var_len(r->tlv3, cursor, plen);
  +	r->tlv3->varlen_assigned = fromwire_subtype_var_assign(r->tlv3, cursor, plen);
  +	r->tlv3->test_sbt_varlen_varsize = fromwire_subtype_varlen_varsize(r->tlv3, cursor, plen);
   		for (size_t i = 0; i < 2; i++) {
   		u32 tmp;
   		tmp = fromwire_u32(cursor, plen);
  diff -ur /tmp/before/test/gen_test.h /tmp/after/test/gen_test.h
  --- /tmp/before/test/gen_test.h	2020-05-07 16:23:30.399617108 +0930
  +++ /tmp/after/test/gen_test.h	2020-05-07 16:20:52.912584680 +0930
  @@ -45,7 +45,7 @@
           struct test_short_id field_1;
   };
   struct subtype_varsize_struct {
  -        struct test_features field_0;
  +        struct test_features *field_0;
   };
   struct subtype_var_len {
           struct test_short_id *field_2;
  @@ -60,15 +60,15 @@
           struct test_short_id field3[2];
   };
   struct tlv_test_n1_tlv3 {
  -        struct test_features features;
  +        struct test_features *features;
           struct amount_msat amount_msat_1;
           struct amount_msat amount_msat_2;
   };
   struct tlv_test_n3_tlv3 {
           struct test_short_id subtype;
  -        struct subtype_var_len varlen_subtype;
  -        struct subtype_var_assign varlen_assigned;
  -        struct subtype_varlen_varsize test_sbt_varlen_varsize;
  +        struct subtype_var_len *varlen_subtype;
  +        struct subtype_var_assign *varlen_assigned;
  +        struct subtype_varlen_varsize *test_sbt_varlen_varsize;
           /*  array assigtest_nable */
           u32 arr_assign[2];
           /*  array structs */
  Binary files /tmp/before/test/gen_test.o and /tmp/after/test/gen_test.o differ
  Binary files /tmp/before/test/run-test-wire and /tmp/after/test/run-test-wire differ
  Binary files /tmp/before/test/run-test-wire.o and /tmp/after/test/run-test-wire.o differ
```

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell 2020-08-25 12:54:13 +09:30
parent be0038e49b
commit 76813d6f90
2 changed files with 3 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
tools/gen/header_template
View file

@ -49,7 +49,7 @@ struct ${struct.struct_name()} {
% endif
% if f.is_varlen() and f.type_obj.is_varsize():
${f.type_obj.type_name()} **${f.name};
% elif f.is_varlen():
% elif f.is_varlen() or f.type_obj.is_varsize():
${f.type_obj.type_name()} *${f.name};
% elif f.is_array():
${f.type_obj.type_name()} ${f.name}[${f.count}];

4
tools/gen/impl_template
View file

@ -64,7 +64,7 @@ towire_${type_obj.name}(${ptr}, ${f.name});
% elif is_single_ptr:
towire_${type_obj.name}(${ptr}, ${'*' if type_obj.is_assignable() else ''}${fieldname});
% else:
towire_${type_obj.name}(${ptr}, ${'' if type_obj.is_assignable() else '&'}${fieldname});
towire_${type_obj.name}(${ptr}, ${'' if type_obj.is_assignable() or type_obj.is_varsize() else '&'}${fieldname});
% endif
</%def>
## Subtype and TLV-msg fromwire
@ -110,7 +110,7 @@ ${fieldname} = ${f.size('*plen')} ? tal_arr(${ctx}, ${typename}, 0) : NULL;
% if f.type_obj.is_assignable():
${ f.name if f.len_field_of else fieldname} = fromwire_${type_}(cursor, plen);
% elif f.type_obj.is_varsize():
${fieldname} = *fromwire_${type_}(${ctx}, cursor, plen);
${fieldname} = fromwire_${type_}(${ctx}, cursor, plen);
% else:
fromwire_${type_}(cursor, plen, &${fieldname});
% endif