Re: [Qemu-devel] [PATCH v1] log: fix parsing of multiple trace:PATTERN log args

[Paolo Bonzini <pbonzini@redhat.com>]

On 06/09/2016 20:25, Daniel P. Berrange wrote:
> If giving QEMU a log arg which asks to enable multiple
> different trace event patterns such as
> 
>   $QEMU -d trace:qio*,trace:qcrypto*
> 
> the parser will then invoke
> 
>   trace_enable_events("qio*,trace:qcrypto*")
>   trace_enable_events("qcrypto*")
> 
> as when finding a 'trace:' prefix, it is not clever
> enough to strip anything after the next comma. As
> a result only the last 'trace:' match ever works.
> 
> Rather than trying to be more clever with parsing the
> command line arg in place, simplify the code by
> using g_strsplit to break it into individual strings
> on ','. These resulting pieces can be directly used
> without worrying about trailing data from the next
> option.
> 
> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> ---
>  util/log.c | 41 +++++++++++++++--------------------------
>  1 file changed, 15 insertions(+), 26 deletions(-)
> 
> diff --git a/util/log.c b/util/log.c
> index 54b54e8..e077340 100644
> --- a/util/log.c
> +++ b/util/log.c
> @@ -275,53 +275,42 @@ const QEMULogItem qemu_log_items[] = {
>      { 0, NULL, NULL },
>  };
>  
> -static int cmp1(const char *s1, int n, const char *s2)
> -{
> -    if (strlen(s2) != n) {
> -        return 0;
> -    }
> -    return memcmp(s1, s2, n) == 0;
> -}
> -
>  /* takes a comma separated list of log masks. Return 0 if error. */
>  int qemu_str_to_log_mask(const char *str)
>  {
>      const QEMULogItem *item;
> -    int mask;
> -    const char *p, *p1;
> +    int mask = 0;
> +    char **parts = g_strsplit(str, ",", 0);
> +    char **tmp;
>  
> -    p = str;
> -    mask = 0;
> -    for (;;) {
> -        p1 = strchr(p, ',');
> -        if (!p1) {
> -            p1 = p + strlen(p);
> -        }
> -        if (cmp1(p,p1-p,"all")) {
> +    for (tmp = parts; tmp && *tmp; tmp++) {
> +        if (g_str_equal(*tmp, "all")) {
>              for (item = qemu_log_items; item->mask != 0; item++) {
>                  mask |= item->mask;
>              }
>  #ifdef CONFIG_TRACE_LOG
> -        } else if (strncmp(p, "trace:", 6) == 0 && p + 6 != p1) {
> -            trace_enable_events(p + 6);
> +        } else if (g_str_has_prefix(*tmp, "trace:") && (*tmp)[6] != '\0') {
> +            trace_enable_events((*tmp) + 6);
>              mask |= LOG_TRACE;
>  #endif
>          } else {
>              for (item = qemu_log_items; item->mask != 0; item++) {
> -                if (cmp1(p, p1 - p, item->name)) {
> +                if (g_str_equal(*tmp, item->name)) {
>                      goto found;
>                  }
>              }
> -            return 0;
> +            goto error;
>          found:
>              mask |= item->mask;
>          }
> -        if (*p1 != ',') {
> -            break;
> -        }
> -        p = p1 + 1;
>      }
> +
> +    g_strfreev(parts);
>      return mask;
> +
> + error:
> +    g_strfreev(parts);
> +    return 0;
>  }
>  
>  void qemu_print_log_usage(FILE *f)
> 

Queued, thanks.

Paolo