Re: PATCH: Fix TUI null pointer dereference

[Andrew STUBBS <andrew.stubbs@st.com>]

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Jim Blandy wrote:
> Andrew STUBBS <andrew.stubbs@st.com> writes:
> 
>>Index: src/gdb/tui/tui-command.c
>>===================================================================
>>--- src.orig/gdb/tui/tui-command.c	2004-02-16 21:05:09.000000000 +0000
>>+++ src/gdb/tui/tui-command.c	2005-10-17 14:33:06.000000000 +0100
>>@@ -70,7 +70,7 @@ tui_dispatch_ctrl_char (unsigned int ch)
>>       term = (char *) getenv ("TERM");
>>       for (i = 0; (term && term[i]); i++)
>> 	term[i] = toupper (term[i]);
>>-      if ((strcmp (term, "XTERM") == 0) && key_is_start_sequence (ch))
>>+      if (term && (strcmp (term, "XTERM") == 0) && key_is_start_sequence (ch))
>> 	{
>> 	  unsigned int page_ch = 0;
>> 	  unsigned int tmp_char;
> 
> 
> How about wrapping the upcasing loop and the 'if' after it all in one
> big 'if (term), starting right after the 'getenv ("TERM")', and then
> simplifying the conditional in the upcasing loop?
> 

How about the attached? Diff has made it look rather confusing, but I 
assure you the only thing that has changed is the indenting and the 
extra if.

Andrew Stubbs

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2005-10-24  Andrew Stubbs  <andrew.stubbs@st.com>

	* tui/tui-command.c (tui_dispatch_ctrl_char): Test output of
	getenv() before using it.


Index: src/gdb/tui/tui-command.c
===================================================================
--- src.orig/gdb/tui/tui-command.c	2005-10-24 13:58:38.000000000 +0100
+++ src/gdb/tui/tui-command.c	2005-10-24 14:11:02.000000000 +0100
@@ -67,34 +67,36 @@ tui_dispatch_ctrl_char (unsigned int ch)
          ** by keypad as a single char, so we must handle them here.
          ** Seems like a bug in the curses library?
        */
-      term = (char *) getenv ("TERM");
-      for (i = 0; (term && term[i]); i++)
-	term[i] = toupper (term[i]);
-      if ((strcmp (term, "XTERM") == 0) && key_is_start_sequence (ch))
+      if (term = (char *) getenv ("TERM"))
 	{
-	  unsigned int page_ch = 0;
-	  unsigned int tmp_char;
-
-	  tmp_char = 0;
-	  while (!key_is_end_sequence (tmp_char))
+	  for (i = 0; term[i]; i++)
+	    term[i] = toupper (term[i]);
+	  if ((strcmp (term, "XTERM") == 0) && key_is_start_sequence (ch))
 	    {
-	      tmp_char = (int) wgetch (w);
-	      if (tmp_char == ERR)
-		{
-		  return ch;
-		}
-	      if (!tmp_char)
-		break;
-	      if (tmp_char == 53)
-		page_ch = KEY_PPAGE;
-	      else if (tmp_char == 54)
-		page_ch = KEY_NPAGE;
-	      else
+	      unsigned int page_ch = 0;
+	      unsigned int tmp_char;
+
+	      tmp_char = 0;
+	      while (!key_is_end_sequence (tmp_char))
 		{
-		  return 0;
+		  tmp_char = (int) wgetch (w);
+		  if (tmp_char == ERR)
+		    {
+		      return ch;
+		    }
+		  if (!tmp_char)
+		    break;
+		  if (tmp_char == 53)
+		    page_ch = KEY_PPAGE;
+		  else if (tmp_char == 54)
+		    page_ch = KEY_NPAGE;
+		  else
+		    {
+		      return 0;
+		    }
 		}
+	      ch_copy = page_ch;
 	    }
-	  ch_copy = page_ch;
 	}
 
       switch (ch_copy)