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

From: Wang Nan
Date: Fri Mar 13 2015 - 08:52:38 EST


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@xxxxxxxxxx>
---
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) \
--
1.8.3.4

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