Re: [Qemu-devel] [PATCH for-3.2 29/41] slirp: improve a bit the debug macros

[Daniel P . Berrangé]

On Wed, Nov 14, 2018 at 04:36:31PM +0400, Marc-André Lureau wrote:
> Let them accept multiple arguments. Simplify the inner argument
> handling of DEBUG_ARGS/DEBUG_MISC_DEBUG_ERROR.
> 
> Signed-off-by: Marc-André Lureau <address@hidden>
> ---
>  slirp/debug.h      | 47 ++++++++++++++++++++++++++++++++++++----------
>  slirp/arp_table.c  | 12 ++++++------
>  slirp/bootp.c      |  3 +--
>  slirp/cksum.c      |  4 ++--
>  slirp/dhcpv6.c     | 11 +++++------
>  slirp/ip6_icmp.c   |  2 +-
>  slirp/ip_icmp.c    | 18 +++++++++---------
>  slirp/mbuf.c       |  2 +-
>  slirp/ndp_table.c  | 18 +++++++++---------
>  slirp/slirp.c      | 12 ++++++------
>  slirp/socket.c     | 32 +++++++++++++++----------------
>  slirp/tcp_input.c  | 15 +++++++--------
>  slirp/tcp_output.c |  2 +-
>  slirp/tcp_subr.c   |  4 ++--
>  slirp/udp.c        |  6 +++---
>  slirp/udp6.c       |  6 +++---
>  16 files changed, 109 insertions(+), 85 deletions(-)
> 
> diff --git a/slirp/debug.h b/slirp/debug.h
> index 6cfa61edb3..ca3a4b04da 100644
> --- a/slirp/debug.h
> +++ b/slirp/debug.h
> @@ -17,18 +17,45 @@
>  
>  extern int slirp_debug;
>  
> -#define DEBUG_CALL(x) if (slirp_debug & DBG_CALL) { fprintf(dfd, "%s...\n", 
> x); fflush(dfd); }
> -#define DEBUG_ARG(x, y) if (slirp_debug & DBG_CALL) { fputc(' ', dfd); 
> fprintf(dfd, x, y); fputc('\n', dfd); fflush(dfd); }
> -#define DEBUG_ARGS(x) if (slirp_debug & DBG_CALL) { fprintf x ; fflush(dfd); 
> }
> -#define DEBUG_MISC(x) if (slirp_debug & DBG_MISC) { fprintf x ; fflush(dfd); 
> }
> -#define DEBUG_ERROR(x) if (slirp_debug & DBG_ERROR) {fprintf x ; 
> fflush(dfd); }
> +#define DEBUG_CALL(fmt, ...) do {               \
> +    if (slirp_debug & DBG_CALL) {               \
> +        fprintf(dfd, fmt, ##__VA_ARGS__);       \
> +        fprintf(dfd, "...\n");                  \
> +        fflush(dfd);                            \
> +    }                                           \
> +} while (0)
> +
> +#define DEBUG_ARG(fmt, ...) do {                \
> +    if (slirp_debug & DBG_CALL) {               \
> +        fputc(' ', dfd);                        \
> +        fprintf(dfd, fmt, ##__VA_ARGS__);       \
> +        fputc('\n', dfd);                       \
> +        fflush(dfd);                            \
> +    }                                           \
> +} while (0)
> +
> +#define DEBUG_ARGS(fmt, ...) DEBUG_ARG(fmt, ##__VA_ARGS__)
> +
> +#define DEBUG_MISC(fmt, ...) do {               \
> +    if (slirp_debug & DBG_MISC) {               \
> +        fprintf(dfd, fmt, ##__VA_ARGS__);       \
> +        fflush(dfd);                            \
> +    }                                           \
> +} while (0)
> +
> +#define DEBUG_ERROR(fmt, ...) do {              \
> +    if (slirp_debug & DBG_ERROR) {              \
> +        fprintf(dfd, fmt, ##__VA_ARGS__);       \
> +        fflush(dfd);                            \
> +    }                                           \
> +} while (0)

I tend to think it would be nicer to change these to
use  g_debug, and #define G_LOG_DOMAIN  "libslirp" in
the .c files.

This would allow apps to intercept the debug messages
via a custom log handler.

Regards,
Daniel
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