[PATCH] herewrite: check for dictionary overflow

[Igor V. Kovalenko]

From: Igor V. Kovalenko

- add dictlimit variable to store dictionary memory size
- change herewrite() to check for overflow if dictlimit is set
- sparc64: set dictlimit to allocated amount

Signed-off-by: Igor V. Kovalenko 
---
 arch/sparc64/openbios.c |    2 ++
 kernel/dict.c           |    1 +
 kernel/forth.c          |    8 ++++++++
 kernel/include/dict.h   |    1 +
 4 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/arch/sparc64/openbios.c b/arch/sparc64/openbios.c
index 2f1a955..67849e1 100644
--- a/arch/sparc64/openbios.c
+++ b/arch/sparc64/openbios.c
@@ -519,6 +519,8 @@ int openbios(void)
         collect_sys_info(&sys_info);

dict = malloc(DICTIONARY_SIZE);
+        dictlimit = DICTIONARY_SIZE;
+
    load_dictionary((char *)sys_info.dict_start,
    		(unsigned long)sys_info.dict_end
                         - (unsigned long)sys_info.dict_start);
diff --git a/kernel/dict.c b/kernel/dict.c
index 34b97f3..822c923 100644
--- a/kernel/dict.c
+++ b/kernel/dict.c
@@ -21,6 +21,7 @@
 unsigned char *dict = NULL;
 ucell *last;
 cell dicthead = 0;
+ucell dictlimit = 0;

/* lfa2nfa
  * converts a link field address to a name field address,
diff --git a/kernel/forth.c b/kernel/forth.c
index 5fc53d3..2876709 100644
--- a/kernel/forth.c
+++ b/kernel/forth.c
@@ -851,6 +851,14 @@ static void herewrite(void)
 #ifdef CONFIG_DEBUG_INTERNAL
    printk("here!: new value: %x\n", tmp);
 #endif
+
+	if (dictlimit && dicthead >= dictlimit) {
+	    printk("Dictionary space overflow:"
+	            " dicthead=" FMT_ucellx
+	            " dictlimit=" FMT_ucellx
+	            "\n",
+	            dicthead, dictlimit);
+	}
 }

diff --git a/kernel/include/dict.h b/kernel/include/dict.h
index 7e8c320..cc30f99 100644
--- a/kernel/include/dict.h
+++ b/kernel/include/dict.h
@@ -50,6 +50,7 @@ extern ucell 		PC;

extern unsigned char	*dict;
 extern cell 		dicthead;
+extern ucell		dictlimit;
 extern ucell		*last;
 #ifdef FCOMPILER
 extern ucell *trampoline;

[Mark Cave-Ayland]

Igor V. Kovalenko wrote:
> From: Igor V. Kovalenko
> add dictlimit variable to store dictionary memory size
> change herewrite() to check for overflow if dictlimit is set
> sparc64: set dictlimit to allocated amount

This patch looks great in that it correctly picks up on the overflow 
condition when added to r740. If you could update it so that it works on 
all archs then I'm happy to apply it.

ATB,

Mark.

[Igor Kovalenko]

On Mon, Apr 12, 2010 at 2:15 PM, Mark Cave-Ayland
 wrote:
> Igor V. Kovalenko wrote:
> > From: Igor V. Kovalenko
> > add dictlimit variable to store dictionary memory size
> > change herewrite() to check for overflow if dictlimit is set
> > sparc64: set dictlimit to allocated amount
>
> This patch looks great in that it correctly picks up on the overflow
> condition when added to r740. If you could update it so that it works on all
> archs then I'm happy to apply it.

I was looking at hiding dict and dictlimit assignment behind
initialization routine
but it is not a priority task now that you applied modified version :)

[Mark Cave-Ayland]

Mark Cave-Ayland wrote:
> This patch looks great in that it correctly picks up on the overflow 
> condition when added to r740. If you could update it so that it works on 
> all archs then I'm happy to apply it.

Turns out that it wasn't too difficult to modify the patch for all 
architectures and so I've applied a revised version of your patch to SVN.

Many thanks,

Mark.