[PATCH] ada-lang.c, null pointer

[PATCH] ada-lang.c, null pointer

[msnyder]

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According to the first line of the function, name may be null.
In which case, we'll crash on the next line.




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Re: [PATCH] ada-lang.c, null pointer

[msnyder]

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> According to the first line of the function, name may be null.
> In which case, we'll crash on the next line.

Err, here's the patch...


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2007-08-11  Michael Snyder  <msnyder@access-company.com>

	* ada-lang.c (field_alignment): Guard against NULL.

Index: ada-lang.c
===================================================================
RCS file: /cvs/src/src/gdb/ada-lang.c,v
retrieving revision 1.100
diff -p -r1.100 ada-lang.c
*** ada-lang.c	6 Aug 2007 20:07:44 -0000	1.100
--- ada-lang.c	11 Aug 2007 20:25:00 -0000
*************** field_alignment (struct type *type, int 
*** 6119,6125 ****
    int len = (name == NULL) ? 0 : strlen (name);
    int align_offset;
  
!   if (!isdigit (name[len - 1]))
      return 1;
  
    if (isdigit (name[len - 2]))
--- 6119,6125 ----
    int len = (name == NULL) ? 0 : strlen (name);
    int align_offset;
  
!   if (name == NULL || !isdigit (name[len - 1]))
      return 1;
  
    if (isdigit (name[len - 2]))

Re: [PATCH] ada-lang.c, null pointer

[Joel Brobecker]

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Hi Michael,

> 2007-08-11  Michael Snyder  <msnyder@access-company.com>
> 
> 	* ada-lang.c (field_alignment): Guard against NULL.

Thanks again for your patch.

May I propose another patch that is very close in spirit? The diff
is slightly bigger, but it makes the code check for a null name
only once, and allows us to know at a glance what we do in this case.

Let me know what you think.
(proposed patch reg-tested)

> Index: ada-lang.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/ada-lang.c,v
> retrieving revision 1.100
> diff -p -r1.100 ada-lang.c
> *** ada-lang.c	6 Aug 2007 20:07:44 -0000	1.100
> --- ada-lang.c	11 Aug 2007 20:25:00 -0000
> *************** field_alignment (struct type *type, int 
> *** 6119,6125 ****
>     int len = (name == NULL) ? 0 : strlen (name);
>     int align_offset;
>   
> !   if (!isdigit (name[len - 1]))
>       return 1;
>   
>     if (isdigit (name[len - 2]))
> --- 6119,6125 ----
>     int len = (name == NULL) ? 0 : strlen (name);
>     int align_offset;
>   
> !   if (name == NULL || !isdigit (name[len - 1]))
>       return 1;
>   
>     if (isdigit (name[len - 2]))



-- 
Joel

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Index: ada-lang.c
===================================================================
RCS file: /cvs/src/src/gdb/ada-lang.c,v
retrieving revision 1.100
diff -u -p -r1.100 ada-lang.c
--- ada-lang.c	6 Aug 2007 20:07:44 -0000	1.100
+++ ada-lang.c	14 Aug 2007 03:45:04 -0000
@@ -6116,9 +6116,17 @@ static unsigned int
 field_alignment (struct type *type, int f)
 {
   const char *name = TYPE_FIELD_NAME (type, f);
-  int len = (name == NULL) ? 0 : strlen (name);
+  int len;
   int align_offset;
 
+  /* The field name should never be null, unless the debugging information
+     is somehow malformed.  In this case, we assume the field does not
+     require any alignment.  */
+  if (name == NULL)
+    return 1;
+
+  len = strlen (name);
+
   if (!isdigit (name[len - 1]))
     return 1;
 

Re: [PATCH] ada-lang.c, null pointer

[Michael Snyder]

> Hi Michael,
>
> > 2007-08-11  Michael Snyder  <msnyder@access-company.com>
> >
> > * ada-lang.c (field_alignment): Guard against NULL.
>
> Thanks again for your patch.
>
> May I propose another patch that is very close in spirit? The diff
> is slightly bigger, but it makes the code check for a null name
> only once, and allows us to know at a glance what we do in this case.
>
> Let me know what you think.
> (proposed patch reg-tested)

Yeah, Joel, that looks fine to me.  You want to check it in?
Michael

Re: [PATCH] ada-lang.c, null pointer

[Joel Brobecker]

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> Yeah, Joel, that looks fine to me.  You want to check it in?

Cool!

2007-08-14  Joel Brobecker  <brobecker@adacore.com>
            Michael Snyder  <msnyder@access-company.com>

        * ada-lang.c (field_alignment): Guard against NULL.

I have checked this in.

Thanks again, Michael.
-- 
Joel

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Index: ada-lang.c
===================================================================
RCS file: /cvs/src/src/gdb/ada-lang.c,v
retrieving revision 1.100
diff -u -p -r1.100 ada-lang.c
--- ada-lang.c	6 Aug 2007 20:07:44 -0000	1.100
+++ ada-lang.c	14 Aug 2007 03:45:04 -0000
@@ -6116,9 +6116,17 @@ static unsigned int
 field_alignment (struct type *type, int f)
 {
   const char *name = TYPE_FIELD_NAME (type, f);
-  int len = (name == NULL) ? 0 : strlen (name);
+  int len;
   int align_offset;
 
+  /* The field name should never be null, unless the debugging information
+     is somehow malformed.  In this case, we assume the field does not
+     require any alignment.  */
+  if (name == NULL)
+    return 1;
+
+  len = strlen (name);
+
   if (!isdigit (name[len - 1]))
     return 1;