Re: [PATCH 5 of 7] Add dynamic device tree manipulation & change uboot loader for PPC bamboo board model

[Jerone Young <jyoung5@us.ibm.com>]

On Wed, 2008-03-19 at 14:30 -0500, Anthony Liguori wrote:
> Jerone Young wrote:
> > # HG changeset patch
> > # User Jerone Young <jyoung5@us.ibm.com>
> > # Date 1205953012 18000
> > # Branch merge
> > # Node ID 8e9da5ddf159eb6cf5a292ccbf5f735103b493ef
> > # Parent  03925441312877b8350e4af68e475d5d746304d4
> > Add dynamic device tree manipulation & change uboot loader for PPC bamboo board model
> >
> > This patch adds code to dynamically manipulate the device tree when loaded into memory. This allows us to finally have the ability to manipulate the kernel command line & initrd from the qemu command line. This will also let us setup different settings for the board.
> >
> > This patch also now uses new uboot loader load_uimage() to load kernel image.
> >
> > Signed-off-by: Jerone Young <jyoung5@us.ibm.com>
> >
> > diff --git a/qemu/Makefile.target b/qemu/Makefile.target
> > --- a/qemu/Makefile.target
> > +++ b/qemu/Makefile.target
> > @@ -617,7 +617,7 @@ OBJS+= unin_pci.o ppc_chrp.o
> >  OBJS+= unin_pci.o ppc_chrp.o
> >  # PowerPC 4xx boards
> >  OBJS+= pflash_cfi02.o ppc4xx_devs.o ppc405_uc.o ppc405_boards.o
> > -OBJS+= ppc440.o ppc440_bamboo.o
> > +OBJS+= ppc440.o ppc440_bamboo.o device_tree.o
> >  endif
> >  ifeq ($(TARGET_BASE_ARCH), mips)
> >  OBJS+= mips_r4k.o mips_malta.o mips_pica61.o mips_mipssim.o
> > diff --git a/qemu/hw/device_tree.c b/qemu/hw/device_tree.c
> > new file mode 100644
> > --- /dev/null
> > +++ b/qemu/hw/device_tree.c
> > @@ -0,0 +1,181 @@
> > +/*
> > + * Functions to help device tree manipulation using libfdt.
> > + * It also provides functions to read entries from device tree proc
> > + * interface.
> > + *
> > + * Copyright 2008 IBM Corporation.
> > + * Authors: Jerone Young <jyoung5@us.ibm.com>
> > + *
> > + * This work is licensed under the GNU GPL license version 2 or later.
> > + *
> > + */
> > +
> > +#include <stdio.h>
> > +#include <sys/types.h>
> > +#include <sys/stat.h>
> > +#include <fcntl.h>
> > +#include <unistd.h>
> > +#include <stdlib.h>
> > +
> > +#include "config.h"
> > +#include "ppc440.h"
> > +
> > +#ifdef CONFIG_LIBFDT
> > +#include "libfdt.h"
> > +#endif
> > +
> > +#define DT_PROC_INTERFACE_PATH "/proc/device-tree"
> > +
> > +/* FUNCTIONS FOR READING FROM DEVICE TREE OF HOST IN /PROC */
> > +
> > +/* This function reads device-tree property files that are of
> > + * a single cell size
> > + */
> > +uint32_t read_proc_dt_prop_cell(char *path_in_device_tree)
> > +{
> > +	char *buf = NULL;
> > +	int i;
> > +	uint32_t num;
> > +	FILE *stream;
> > +
> > +	i = snprintf(buf, 0, "%s/%s", DT_PROC_INTERFACE_PATH,
> > +		path_in_device_tree);
> > +
> > +	buf = (char *)malloc(i);
> > +	if (buf == NULL) {
> > +		printf("%s: Unable to malloc string buffer buf\n",
> > +			__func__);
> > +		exit(1);
> > +	}
> > +
> > +	i = snprintf(buf, i+1, "%s/%s",  DT_PROC_INTERFACE_PATH,
> > +		path_in_device_tree);
> >   
> 
> asprintf() is the right thing to do here.  You allocate 'i' bytes but 
> then snprintf() to 'i + 1' bytes, that's a buffer overflow.

Ouch! Yes this has to be fixed. Not sure why I did this, but

> 
> > +fail:
> > +	if (dt_file) 
> > +		qemu_free(dt_file);
> > +	return NULL;
> > +}
> > +
> > +void dump_device_tree_to_file(void *fdt, char *filename)
> > +{
> > +	int fd;
> > +	fd = open(filename, O_RDWR|O_CREAT);
> >   
> 
> Need to pass a permission mask when using O_CREAT.

I'll fix this also.

> 
> Regards,
> 
> Anthony LIguori
> 
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