PR29262, memory leak in pr_function_type

[binutils-gdb.git] / gdb / top.c

diff --git a/gdb/top.c b/gdb/top.c
index e776ac2d70e1173335d2b9abb9bbcc9a442c38cd..86c9971fa6dfb48e8301a58bfe09e785b109a2ce 100644 (file)
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -257,6 +257,41 @@ void (*deprecated_context_hook) (int id);
 /* The highest UI number ever assigned.  */
 static int highest_ui_num;
 
+/* Unbuffer STREAM.  This is a wrapper around setbuf(STREAM, nullptr)
+   which applies some special rules for MS-Windows hosts.  */
+
+static void
+unbuffer_stream (FILE *stream)
+{
+  /* Unbuffer the input stream so that in gdb_readline_no_editing_callback,
+     the calls to fgetc fetch only one char at the time from STREAM.
+
+     This is important because gdb_readline_no_editing_callback will read
+     from STREAM up to the first '\n' character, after this GDB returns to
+     the event loop and relies on a select on STREAM indicating that more
+     input is pending.
+
+     If STREAM is buffered then the fgetc calls may have moved all the
+     pending input from the kernel into a local buffer, after which the
+     select will not indicate that more input is pending, and input after
+     the first '\n' will not be processed immediately.
+
+     Please ensure that any changes in this area run the MI tests with the
+     FORCE_SEPARATE_MI_TTY=1 flag being passed.  */
+
+#ifdef __MINGW32__
+  /* With MS-Windows runtime, making stdin unbuffered when it's
+     connected to the terminal causes it to misbehave.  */
+  if (!ISATTY (stream))
+    setbuf (stream, nullptr);
+#else
+  /* On GNU/Linux the issues described above can impact GDB even when
+     dealing with input from a terminal.  For now we unbuffer the input
+     stream for everyone except MS-Windows.  */
+  setbuf (stream, nullptr);
+#endif
+}
+
 /* See top.h.  */
 
 ui::ui (FILE *instream_, FILE *outstream_, FILE *errstream_)
@@ -283,6 +318,8 @@ ui::ui (FILE *instream_, FILE *outstream_, FILE *errstream_)
 {
   buffer_init (&line_buffer);
 
+  unbuffer_stream (instream_);
+
   if (ui_list == NULL)
     ui_list = this;
   else
@@ -412,6 +449,8 @@ read_command_file (FILE *stream)
 {
   struct ui *ui = current_ui;
 
+  unbuffer_stream (stream);
+
   scoped_restore save_instream
     = make_scoped_restore (&ui->instream, stream);
 
@@ -2167,12 +2206,7 @@ set_history_filename (const char *args,
      that was read.  */
   if (!history_filename.empty ()
       && !IS_ABSOLUTE_PATH (history_filename.c_str ()))
-    {
-      gdb::unique_xmalloc_ptr<char> temp
-       (gdb_abspath (history_filename.c_str ()));
-
-      history_filename = temp.get ();
-    }
+    history_filename = gdb_abspath (history_filename.c_str ());
 }
 
 /* Whether we're in quiet startup mode.  */
@@ -2230,6 +2264,7 @@ init_main (void)
   rl_completion_display_matches_hook = cli_display_match_list;
   rl_readline_name = "gdb";
   rl_terminal_name = getenv ("TERM");
+  rl_deprep_term_function = gdb_rl_deprep_term_function;
 
   /* The name for this defun comes from Bash, where it originated.
      15 is Control-o, the same binding this function has in Bash.  */
@@ -2444,7 +2479,6 @@ _initialize_top ()
       const char *fname = ".gdb_history";
 #endif
 
-      gdb::unique_xmalloc_ptr<char> temp (gdb_abspath (fname));
-      history_filename = temp.get ();
+      history_filename = gdb_abspath (fname);
     }
 }