perf report: Don't allow empty argument for '-t'.

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>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: pi3orama@163.com
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Link: http://lkml.kernel.org/r/1426251114-198991-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 52f74e1367e9..0ae482689e3c 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,