[binutils-gdb] Fix leak in event-top.c history expansion

[Philippe Waroquiers <philippe at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=b6fb1ee51c9a773d2d6044993af6c0fd7499638f

commit b6fb1ee51c9a773d2d6044993af6c0fd7499638f
Author: Philippe Waroquiers <philippe.waroquiers@skynet.be>
Date:   Sun Jan 20 16:59:00 2019 +0100

    Fix leak in event-top.c history expansion
    
    E.g. in gdb.base/default.exp, valgrind detects leaks such as
    ==17663== 1,438 bytes in 101 blocks are definitely lost in loss record 2,804 of 2,884
    ==17663==    at 0x4C2BE6D: malloc (vg_replace_malloc.c:309)
    ==17663==    by 0x418A17: xmalloc (common-utils.c:44)
    ==17663==    by 0x4E6F19C: history_expand (histexpand.c:1061)
    ==17663==    by 0x4B4490: handle_line_of_input(buffer*, char const*, int, char const*) (event-top.c:685)
    ==17663==    by 0x4B4562: command_line_handler(std::unique_ptr<char, gdb::xfree_deleter<char> >&&) (event-top.c:753)
    ...
    
    Fix the leak by using an unique_xmalloc_ptr for history_value.
    
    gdb/ChangeLog
    2019-01-22  Philippe Waroquiers  <philippe.waroquiers@skynet.be>
    
    	* event-top.c (handle_line_of_input): use unique_xmalloc_ptr for
    	history_value.

Diff:
---
 gdb/ChangeLog   |  5 +++++
 gdb/event-top.c | 18 ++++++++----------
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 04e8c2d..8e03dbf 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2019-01-22  Philippe Waroquiers  <philippe.waroquiers@skynet.be>
+
+	* event-top.c (handle_line_of_input): use unique_xmalloc_ptr for
+	history_value.
+
 2019-01-21  Tom Tromey  <tom@tromey.com>
 
 	* ui-out.c: Fix includes.
diff --git a/gdb/event-top.c b/gdb/event-top.c
index 3d3d627..920b47f 100644
--- a/gdb/event-top.c
+++ b/gdb/event-top.c
@@ -679,31 +679,29 @@ handle_line_of_input (struct buffer *cmd_line_buffer,
   /* Do history expansion if that is wished.  */
   if (history_expansion_p && from_tty && input_interactive_p (current_ui))
     {
-      char *history_value;
+      char *cmd_expansion;
       int expanded;
 
-      expanded = history_expand (cmd, &history_value);
+      expanded = history_expand (cmd, &cmd_expansion);
+      gdb::unique_xmalloc_ptr<char> history_value (cmd_expansion);
       if (expanded)
 	{
 	  size_t len;
 
 	  /* Print the changes.  */
-	  printf_unfiltered ("%s\n", history_value);
+	  printf_unfiltered ("%s\n", history_value.get ());
 
 	  /* If there was an error, call this function again.  */
 	  if (expanded < 0)
-	    {
-	      xfree (history_value);
-	      return cmd;
-	    }
+	    return cmd;
 
 	  /* history_expand returns an allocated string.  Just replace
 	     our buffer with it.  */
-	  len = strlen (history_value);
+	  len = strlen (history_value.get ());
 	  xfree (buffer_finish (cmd_line_buffer));
-	  cmd_line_buffer->buffer = history_value;
+	  cmd_line_buffer->buffer = history_value.get ();
 	  cmd_line_buffer->buffer_size = len + 1;
-	  cmd = history_value;
+	  cmd = history_value.release ();
 	}
     }