Re: [PATCH] perf: report: don't allow empty argument for '-t'.

[Namhyung Kim <namhyung@kernel.org>]

On Thu, Mar 19, 2015 at 02:41:42PM +0800, Wang Nan wrote:
> Hi Namhyung Kim,

Hello,

> 
> Do you have any comment on it?

As I said in previous reply, I think perf 'diff' and 'mem' have same
problem.  So how about fix them altogether?

Thanks,
Namhyung


> 
> Thank you.
> 
> On 2015/3/13 20:51, Wang Nan wrote:
> > Without this patch, perf report cause segfault if pass "" as '-t':
> > 
> >   $ perf report -t ""
> > 
> >    # To display the perf.data header info, please use --header/--header-only options.
> >    #
> >    # Samples: 37  of event 'syscalls:sys_enter_write'
> >    # Event count (approx.): 37
> >    #
> >    # Children    SelfCommand   Shared Object         Symbol
> >    Segmentation fault
> > 
> > Since -t is used to add field-separator for generate table, -t "" is
> > actually meanless. This patch defines a new OPT_STRING_NOEMPTY() option
> > generator to ensure user never pass empty string to that option.
> > 
> > Signed-off-by: Wang Nan <wangnan0@huawei.com>
> > ---
> >  tools/perf/builtin-report.c     |  2 +-
> >  tools/perf/util/parse-options.c | 21 +++++++++++++++++++--
> >  tools/perf/util/parse-options.h |  2 ++
> >  3 files changed, 22 insertions(+), 3 deletions(-)
> > 
> > diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
> > index fb35034..2652e52 100644
> > --- a/tools/perf/builtin-report.c
> > +++ b/tools/perf/builtin-report.c
> > @@ -676,7 +676,7 @@ int cmd_report(int argc, const char **argv, const char *prefix __maybe_unused)
> >  	OPT_STRING('w', "column-widths", &symbol_conf.col_width_list_str,
> >  		   "width[,width...]",
> >  		   "don't try to adjust column width, use these fixed values"),
> > -	OPT_STRING('t', "field-separator", &symbol_conf.field_sep, "separator",
> > +	OPT_STRING_NOEMPTY('t', "field-separator", &symbol_conf.field_sep, "separator",
> >  		   "separator for columns, no spaces will be added between "
> >  		   "columns '.' is reserved."),
> >  	OPT_BOOLEAN('U', "hide-unresolved", &report.hide_unresolved,
> > diff --git a/tools/perf/util/parse-options.c b/tools/perf/util/parse-options.c
> > index 1457d66..01626be 100644
> > --- a/tools/perf/util/parse-options.c
> > +++ b/tools/perf/util/parse-options.c
> > @@ -37,6 +37,7 @@ static int get_value(struct parse_opt_ctx_t *p,
> >  {
> >  	const char *s, *arg = NULL;
> >  	const int unset = flags & OPT_UNSET;
> > +	int err;
> >  
> >  	if (unset && p->opt)
> >  		return opterror(opt, "takes no value", flags);
> > @@ -114,13 +115,29 @@ static int get_value(struct parse_opt_ctx_t *p,
> >  		return 0;
> >  
> >  	case OPTION_STRING:
> > +		err = 0;
> >  		if (unset)
> >  			*(const char **)opt->value = NULL;
> >  		else if (opt->flags & PARSE_OPT_OPTARG && !p->opt)
> >  			*(const char **)opt->value = (const char *)opt->defval;
> >  		else
> > -			return get_arg(p, opt, flags, (const char **)opt->value);
> > -		return 0;
> > +			err = get_arg(p, opt, flags, (const char **)opt->value);
> > +
> > +		/* PARSE_OPT_NOEMPTY: Allow NULL but disallow empty string. */
> > +		if (opt->flags & PARSE_OPT_NOEMPTY) {
> > +			const char *val = *(const char **)opt->value;
> > +
> > +			if (!val)
> > +				return err;
> > +
> > +			/* Similar to unset if we are given an empty string. */
> > +			if (val[0] == '\0') {
> > +				*(const char **)opt->value = NULL;
> > +				return 0;
> > +			}
> > +		}
> > +
> > +		return err;
> >  
> >  	case OPTION_CALLBACK:
> >  		if (unset)
> > diff --git a/tools/perf/util/parse-options.h b/tools/perf/util/parse-options.h
> > index 97b153f..59561fd 100644
> > --- a/tools/perf/util/parse-options.h
> > +++ b/tools/perf/util/parse-options.h
> > @@ -40,6 +40,7 @@ enum parse_opt_option_flags {
> >  	PARSE_OPT_LASTARG_DEFAULT = 16,
> >  	PARSE_OPT_DISABLED = 32,
> >  	PARSE_OPT_EXCLUSIVE = 64,
> > +	PARSE_OPT_NOEMPTY  = 128,
> >  };
> >  
> >  struct option;
> > @@ -122,6 +123,7 @@ struct option {
> >  #define OPT_LONG(s, l, v, h)        { .type = OPTION_LONG, .short_name = (s), .long_name = (l), .value = check_vtype(v, long *), .help = (h) }
> >  #define OPT_U64(s, l, v, h)         { .type = OPTION_U64, .short_name = (s), .long_name = (l), .value = check_vtype(v, u64 *), .help = (h) }
> >  #define OPT_STRING(s, l, v, a, h)   { .type = OPTION_STRING,  .short_name = (s), .long_name = (l), .value = check_vtype(v, const char **), (a), .help = (h) }
> > +#define OPT_STRING_NOEMPTY(s, l, v, a, h)   { .type = OPTION_STRING,  .short_name = (s), .long_name = (l), .value = check_vtype(v, const char **), (a), .help = (h), .flags = PARSE_OPT_NOEMPTY}
> >  #define OPT_DATE(s, l, v, h) \
> >  	{ .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l), .value = (v), .argh = "time", .help = (h), .callback = parse_opt_approxidate_cb }
> >  #define OPT_CALLBACK(s, l, v, a, h, f) \
> > 
> 
> 
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