From ce6cb8113c842b94e77364b247c4f85c7b34e0c2 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Mon, 14 Apr 2025 14:18:46 -0700 Subject: [PATCH] tools: ynl-gen: individually free previous values on double set When user calls request_attrA_set() multiple times (for the same attribute), and attrA is of type which allocates memory - we try to free the previously associated values. For array types (including multi-attr) we have only freed the array, but the array may have contained pointers. Refactor the code generation for free attr and reuse the generated lines in setters to flush out the previous state. Since setters are static inlines in the header we need to add forward declarations for the free helpers of pure nested structs. Track which types get used by arrays and include the right forwad declarations. At least ethtool string set and bit set would not be freed without this. Tho, admittedly, overriding already set attribute twice is likely a very very rare thing to do. Fixes: be5bea1cc0bf ("net: add basic C code generators for Netlink") Reviewed-by: Donald Hunter Reviewed-by: Jacob Keller Link: https://patch.msgid.link/20250414211851.602096-4-kuba@kernel.org Signed-off-by: Jakub Kicinski --- tools/net/ynl/pyynl/ynl_gen_c.py | 62 +++++++++++++++++++++++--------- 1 file changed, 45 insertions(+), 17 deletions(-) diff --git a/tools/net/ynl/pyynl/ynl_gen_c.py b/tools/net/ynl/pyynl/ynl_gen_c.py index 662a925bd9e1..2d856ccc88f4 100755 --- a/tools/net/ynl/pyynl/ynl_gen_c.py +++ b/tools/net/ynl/pyynl/ynl_gen_c.py @@ -162,9 +162,15 @@ def _complex_member_type(self, ri): def free_needs_iter(self): return False - def free(self, ri, var, ref): + def _free_lines(self, ri, var, ref): if self.is_multi_val() or self.presence_type() == 'len': - ri.cw.p(f'free({var}->{ref}{self.c_name});') + return [f'free({var}->{ref}{self.c_name});'] + return [] + + def free(self, ri, var, ref): + lines = self._free_lines(ri, var, ref) + for line in lines: + ri.cw.p(line) def arg_member(self, ri): member = self._complex_member_type(ri) @@ -263,6 +269,10 @@ def setter(self, ri, space, direction, deref=False, ref=None): var = "req" member = f"{var}->{'.'.join(ref)}" + local_vars = [] + if self.free_needs_iter(): + local_vars += ['unsigned int i;'] + code = [] presence = '' for i in range(0, len(ref)): @@ -272,6 +282,10 @@ def setter(self, ri, space, direction, deref=False, ref=None): if i == len(ref) - 1 and self.presence_type() != 'bit': continue code.append(presence + ' = 1;') + ref_path = '.'.join(ref[:-1]) + if ref_path: + ref_path += '.' + code += self._free_lines(ri, var, ref_path) code += self._setter_lines(ri, member, presence) func_name = f"{op_prefix(ri, direction, deref=deref)}_set_{'_'.join(ref)}" @@ -279,7 +293,8 @@ def setter(self, ri, space, direction, deref=False, ref=None): alloc = bool([x for x in code if 'alloc(' in x]) if free and not alloc: func_name = '__' + func_name - ri.cw.write_func('static inline void', func_name, body=code, + ri.cw.write_func('static inline void', func_name, local_vars=local_vars, + body=code, args=[f'{type_name(ri, direction, deref=deref)} *{var}'] + self.arg_member(ri)) @@ -482,8 +497,7 @@ def _attr_get(self, ri, var): ['unsigned int len;'] def _setter_lines(self, ri, member, presence): - return [f"free({member});", - f"{presence}_len = strlen({self.c_name});", + return [f"{presence}_len = strlen({self.c_name});", f"{member} = malloc({presence}_len + 1);", f'memcpy({member}, {self.c_name}, {presence}_len);', f'{member}[{presence}_len] = 0;'] @@ -536,8 +550,7 @@ def _attr_get(self, ri, var): ['unsigned int len;'] def _setter_lines(self, ri, member, presence): - return [f"free({member});", - f"{presence}_len = len;", + return [f"{presence}_len = len;", f"{member} = malloc({presence}_len);", f'memcpy({member}, {self.c_name}, {presence}_len);'] @@ -574,12 +587,14 @@ def is_recursive(self): def _complex_member_type(self, ri): return self.nested_struct_type - def free(self, ri, var, ref): + def _free_lines(self, ri, var, ref): + lines = [] at = '&' if self.is_recursive_for_op(ri): at = '' - ri.cw.p(f'if ({var}->{ref}{self.c_name})') - ri.cw.p(f'{self.nested_render_name}_free({at}{var}->{ref}{self.c_name});') + lines += [f'if ({var}->{ref}{self.c_name})'] + lines += [f'{self.nested_render_name}_free({at}{var}->{ref}{self.c_name});'] + return lines def _attr_typol(self): return f'.type = YNL_PT_NEST, .nest = &{self.nested_render_name}_nest, ' @@ -632,15 +647,19 @@ def _complex_member_type(self, ri): def free_needs_iter(self): return 'type' not in self.attr or self.attr['type'] == 'nest' - def free(self, ri, var, ref): + def _free_lines(self, ri, var, ref): + lines = [] if self.attr['type'] in scalars: - ri.cw.p(f"free({var}->{ref}{self.c_name});") + lines += [f"free({var}->{ref}{self.c_name});"] elif 'type' not in self.attr or self.attr['type'] == 'nest': - ri.cw.p(f"for (i = 0; i < {var}->{ref}n_{self.c_name}; i++)") - ri.cw.p(f'{self.nested_render_name}_free(&{var}->{ref}{self.c_name}[i]);') - ri.cw.p(f"free({var}->{ref}{self.c_name});") + lines += [ + f"for (i = 0; i < {var}->{ref}n_{self.c_name}; i++)", + f'{self.nested_render_name}_free(&{var}->{ref}{self.c_name}[i]);', + f"free({var}->{ref}{self.c_name});", + ] else: raise Exception(f"Free of MultiAttr sub-type {self.attr['type']} not supported yet") + return lines def _attr_policy(self, policy): return self.base_type._attr_policy(policy) @@ -666,8 +685,7 @@ def attr_put(self, ri, var): def _setter_lines(self, ri, member, presence): # For multi-attr we have a count, not presence, hack up the presence presence = presence[:-(len('_present.') + len(self.c_name))] + "n_" + self.c_name - return [f"free({member});", - f"{member} = {self.c_name};", + return [f"{member} = {self.c_name};", f"{presence} = n_{self.c_name};"] @@ -755,6 +773,7 @@ def __init__(self, family, space_name, type_list=None, inherited=None): self.request = False self.reply = False self.recursive = False + self.in_multi_val = False # used by a MultiAttr or and legacy arrays self.attr_list = [] self.attrs = dict() @@ -1122,6 +1141,10 @@ def _load_nested_sets(self): if attr in rs_members['reply']: self.pure_nested_structs[nested].reply = True + if spec.is_multi_val(): + child = self.pure_nested_structs.get(nested) + child.in_multi_val = True + self._sort_pure_types() # Propagate the request / reply / recursive @@ -1136,6 +1159,8 @@ def _load_nested_sets(self): struct.child_nests.update(child.child_nests) child.request |= struct.request child.reply |= struct.reply + if spec.is_multi_val(): + child.in_multi_val = True if attr_set in struct.child_nests: struct.recursive = True @@ -2958,6 +2983,9 @@ def main(): for attr_set, struct in parsed.pure_nested_structs.items(): ri = RenderInfo(cw, parsed, args.mode, "", "", attr_set) print_type_full(ri, struct) + if struct.request and struct.in_multi_val: + free_rsp_nested_prototype(ri) + cw.nl() for op_name, op in parsed.ops.items(): cw.p(f"/* ============== {op.enum_name} ============== */")