[04/11] nss_files: Use generic result pointer in parse_line

As a result, all parse_line functions have the same prototype, except
for that producing struct hostent.  This change is ABI-compatible, so
it does not alter the internal GLIBC_PRIVATE ABI (otherwise we should
probably have renamed the exported functions).

A future change will use this to implement a generict fget*ent_r
function.
---
 include/nss_files.h         | 48 ++++++++++---------------------------
 nss/nss_files/files-parse.c |  5 ++--
 2 files changed, 15 insertions(+), 38 deletions(-)

On 7/17/20 4:30 AM, Florian Weimer via Libc-alpha wrote:
> As a result, all parse_line functions have the same prototype, except
> for that producing struct hostent.  This change is ABI-compatible, so
> it does not alter the internal GLIBC_PRIVATE ABI (otherwise we should
> probably have renamed the exported functions).
> 
> A future change will use this to implement a generict fget*ent_r
> function.

OK for 2.32.

Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>

> ---
>  include/nss_files.h         | 48 ++++++++++---------------------------
>  nss/nss_files/files-parse.c |  5 ++--
>  2 files changed, 15 insertions(+), 38 deletions(-)
> 
> diff --git a/include/nss_files.h b/include/nss_files.h
> index 54b354afb3..d0f26815b5 100644
> --- a/include/nss_files.h
> +++ b/include/nss_files.h
> @@ -26,45 +26,21 @@ FILE *__nss_files_fopen (const char *path);
>  libc_hidden_proto (__nss_files_fopen)
>  
>  struct parser_data;
> -struct etherent;
> -struct group;
> -struct netent;
> -struct passwd;
> -struct protoent;
> -struct rpcent;
> -struct servent;
> -struct sgrp;
> -struct spwd;
>  
>  /* Instances of the parse_line function from
>     nss/nss_files/files-parse.c.  */
> -extern int _nss_files_parse_etherent (char *line, struct etherent *result,
> -                                      struct parser_data *data,
> -                                      size_t datalen, int *errnop);
> -extern int _nss_files_parse_grent (char *line, struct group *result,
> -                                   struct parser_data *data,
> -                                   size_t datalen, int *errnop);
> -extern int _nss_files_parse_netent (char *line, struct netent *result,
> -                                    struct parser_data *data,
> -                                    size_t datalen, int *errnop);
> -extern int _nss_files_parse_protoent (char *line, struct protoent *result,
> -                                      struct parser_data *data,
> -                                      size_t datalen, int *errnop);
> -extern int _nss_files_parse_pwent (char *line, struct passwd *result,
> -                                   struct parser_data *data,
> -                                   size_t datalen, int *errnop);
> -extern int _nss_files_parse_rpcent (char *line, struct rpcent *result,
> -                                    struct parser_data *data,
> -                                    size_t datalen, int *errnop);
> -extern int _nss_files_parse_servent (char *line, struct servent *result,
> -                                     struct parser_data *data,
> -                                     size_t datalen, int *errnop);
> -extern int _nss_files_parse_sgent (char *line, struct sgrp *result,
> -                                   struct parser_data *data,
> -                                   size_t datalen, int *errnop);
> -extern int _nss_files_parse_spent (char *line, struct spwd *result,
> -                                   struct parser_data *data,
> -                                   size_t datalen, int *errnop);
> +typedef int nss_files_parse_line (char *line, void *result,
> +                                  struct parser_data *data,
> +                                  size_t datalen, int *errnop);
> +extern nss_files_parse_line _nss_files_parse_etherent;
> +extern nss_files_parse_line _nss_files_parse_grent;
> +extern nss_files_parse_line _nss_files_parse_netent;
> +extern nss_files_parse_line _nss_files_parse_protoent;
> +extern nss_files_parse_line _nss_files_parse_pwent;
> +extern nss_files_parse_line _nss_files_parse_rpcent;
> +extern nss_files_parse_line _nss_files_parse_servent;
> +extern nss_files_parse_line _nss_files_parse_sgent;
> +extern nss_files_parse_line _nss_files_parse_spent;
>  
>  libnss_files_hidden_proto (_nss_files_parse_etherent)
>  libc_hidden_proto (_nss_files_parse_grent)
> diff --git a/nss/nss_files/files-parse.c b/nss/nss_files/files-parse.c
> index 382028765b..c6cd43babe 100644
> --- a/nss/nss_files/files-parse.c
> +++ b/nss/nss_files/files-parse.c
> @@ -87,7 +87,7 @@ struct parser_data
>  #ifdef EXTERN_PARSER
>  
>  /* The parser is defined in a different module.  */
> -extern int parse_line (char *line, struct STRUCTURE *result,
> +extern int parse_line (char *line, void *result,
>  		       struct parser_data *data, size_t datalen, int *errnop
>  		       EXTRA_ARGS_DECL);
>  
> @@ -99,10 +99,11 @@ extern int parse_line (char *line, struct STRUCTURE *result,
>  
>  # define LINE_PARSER(EOLSET, BODY)					      \
>  parser_stclass int							      \
> -parse_line (char *line, struct STRUCTURE *result,			      \
> +parse_line (char *line, void *generic_result,				      \
>  	    struct parser_data *data, size_t datalen, int *errnop	      \
>  	    EXTRA_ARGS_DECL)						      \
>  {									      \
> +  struct STRUCTURE *result = generic_result;				      \
>    ENTDATA_DECL (data)							      \
>    BUFFER_PREPARE							      \
>    char *p = strpbrk (line, EOLSET "\n");				      \
>