vlib: fix unix cli SIGSEGV for empty line input

When logging is enabled, an empty line input (press Enter only)
will cause SIGSEGV. This patch fixes the problem by checking
the command length first.

Type: fix

Signed-off-by: Fan Zhang <roy.fan.zhang@intel.com>
Change-Id: Ib4cbd1c7bfd6a694e289d28958875c7d2356a93e

diff --git a/src/vlib/unix/cli.c b/src/vlib/unix/cli.c
index 6e566d1..2a13c84 100644 (file)
--- a/src/vlib/unix/cli.c
+++ b/src/vlib/unix/cli.c
@@ -2557,7 +2557,8 @@ more:
                   format_timeval, 0 /* current bat-time */ ,
                   0 /* current bat-format */ ,
                   cli_file_index, cf->current_command);
-      if (cf->current_command[vec_len (cf->current_command) - 1] != '\n')
+      if ((vec_len (cf->current_command) > 0) &&
+         (cf->current_command[vec_len (cf->current_command) - 1] != '\n'))
        lv = format (lv, "\n");
       int rv __attribute__ ((unused)) = write (um->log_fd, lv, vec_len (lv));
     }