Re: [PATCH] net: make getname() functions return length rather than use int* parameter

[Denys Vlasenko]

On 02/12/2018 06:47 PM, David Miller wrote:
> From: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
> Date: Mon, 12 Feb 2018 15:15:18 +0100
>
> > Before:
> > All these functions either return a negative error indicator,
> > or store length of sockaddr into "int *socklen" parameter
> > and return zero on success.
> >
> > "int *socklen" parameter is awkward. For example, if caller does not
> > care, it still needs to provide on-stack storage for the value
> > it does not need.
> >
> > None of the many FOO_getname() functions of various protocols
> > ever used old value of *socklen. They always just overwrite it.
> >
> > This change drops this parameter, and makes all these functions, on success,
> > return length of sockaddr. It's always >= 0 and can be differentiated
> > from an error.
> >
> > Tests in callers are changed from "if (err)" to "if (err < 0)", where needed.
> >
> > rpc_sockname() lost "int buflen" parameter, since its only use was
> > to be passed to kernel_getsockname() as &buflen and subsequently
> > not used in any way.
> >
> > Userspace API is not changed.
> >
> >      text    data     bss      dec     hex filename
> > 30108430 2633624  873672 33615726 200ef6e vmlinux.before.o
> > 30108109 2633612  873672 33615393 200ee21 vmlinux.o
> >
> > Signed-off-by: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
>
> Please do an allmodconfig build, there are still some conversions you
> missed:
>
> security/tomoyo/network.c: In function ʽtomoyo_socket_listen_permissionʼ:
> security/tomoyo/network.c:658:19: warning: passing argument 3 of ʽsock->ops->getnameʼ makes integer from pointer without a cast [-Wint-conversion]
>              &addr, &addr_len, 0);
>                     ^
> security/tomoyo/network.c:658:19: note: expected ʽintʼ but argument is of type ʽint *ʼ
> security/tomoyo/network.c:657:21: error: too many arguments to function ʽsock->ops->getnameʼ
>     const int error = sock->ops->getname(sock, (struct sockaddr *)
>                       ^~~~
> fs/dlm/lowcomms.c: In function ʽlowcomms_error_reportʼ:
> fs/dlm/lowcomms.c:495:6: error: too many arguments to function ʽkernel_getpeernameʼ
>        kernel_getpeername(con->sock, (struct sockaddr *)&saddr, &buflen)) {
>        ^~~~~~~~~~~~~~~~~~
> fs/dlm/lowcomms.c: In function ʽtcp_accept_from_sockʼ:
> fs/dlm/lowcomms.c:761:7: warning: passing argument 3 of ʽnewsock->ops->getnameʼ makes integer from pointer without a cast [-Wint-conversion]
>         &len, 2)) {
>         ^
> fs/dlm/lowcomms.c:761:7: note: expected ʽintʼ but argument is of type ʽint *ʼ
> fs/dlm/lowcomms.c:760:6: error: too many arguments to function ʽnewsock->ops->getnameʼ
>    if (newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr,
>        ^~~~~~~

Sorry. Will send updated patch.