partt partition table parser

partt partition table parser

[Jörn Engel]

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Hi!

There has been time for some cleanups, so the code might actually
work. Please have a look and see if this is usable.

Jörn

-- 
``Plan to throw one away; you will, anyhow.'' 
(Fred Brooks, ``The Mythical Man-Month'', Chapter 11)

[-- Attachment #2: partt.patch --]
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diff -Naur mtd.orig/drivers/mtd/Config.in mtd/drivers/mtd/Config.in
--- mtd.orig/drivers/mtd/Config.in	Sun Aug 12 00:00:07 2001
+++ mtd/drivers/mtd/Config.in	Tue Sep 25 20:19:20 2001
@@ -15,6 +15,13 @@
    dep_tristate '  RedBoot partition table parsing' CONFIG_MTD_REDBOOT_PARTS $CONFIG_MTD_PARTITIONS
    dep_tristate '  Compaq bootldr partition table parsing' CONFIG_MTD_BOOTLDR_PARTS $CONFIG_MTD_PARTITIONS
    dep_tristate '  ARM Firmware Suite partition parsing' CONFIG_MTD_AFS_PARTS $CONFIG_MTD_PARTITIONS
+   dep_tristate '  Partt partition table parsing' CONFIG_MTD_PARTT_PARTS $CONFIG_MTD_PARTITIONS
+   if [ "$CONFIG_MTD_PARTT_PARTS" = "y" -o "$CONFIG_MTD_PARTT_PARTS" = "m" ]; then
+      bool      '    use indirect address to partition table' CONFIG_MTD_PARTT_INDIRECT
+      bool      '    seek partition table [pointer] from end' CONFIG_MTD_PARTT_SEEK_FROM_END
+      hex       '    address to partition table [pointer]' CONFIG_MTD_PARTT_ADDRESS 0
+   fi
+
 
 comment 'User Modules And Translation Layers'
    dep_tristate '  Direct char device access to MTD devices' CONFIG_MTD_CHAR $CONFIG_MTD
diff -Naur mtd.orig/drivers/mtd/Makefile mtd/drivers/mtd/Makefile
--- mtd.orig/drivers/mtd/Makefile	Thu Jun 14 00:00:07 2001
+++ mtd/drivers/mtd/Makefile	Tue Sep 25 20:17:50 2001
@@ -48,6 +48,7 @@
 obj-$(CONFIG_MTD_REDBOOT_PARTS) += redboot.o
 obj-$(CONFIG_MTD_BOOTLDR_PARTS) += bootldr.o
 obj-$(CONFIG_MTD_AFS_PARTS)	+= afs.o
+obj-$(CONFIG_MTD_PARTT_PARTS)	+= partt.o
 
 # 'Users' - code which presents functionality to userspace.
 obj-$(CONFIG_MTD_CHAR)		+= mtdchar.o
diff -Naur mtd.orig/drivers/mtd/maps/physmap.c mtd/drivers/mtd/maps/physmap.c
--- mtd.orig/drivers/mtd/maps/physmap.c	Sun Jul 15 00:00:11 2001
+++ mtd/drivers/mtd/maps/physmap.c	Tue Sep 25 20:28:03 2001
@@ -81,8 +81,15 @@
 #define cleanup_physmap cleanup_module
 #endif
 
+#if defined(CONFIG_MTD_PARTT_PARTS)
+static struct mtd_partition *parts;
+#endif
+
 int __init init_physmap(void)
 {
+#if defined(CONFIG_MTD_PARTT_PARTS)
+	int nrparts = 0;
+#endif
        	printk(KERN_NOTICE "physmap flash device: %x at %x\n", WINDOW_SIZE, WINDOW_ADDR);
 	physmap_map.map_priv_1 = (unsigned long)ioremap(WINDOW_ADDR, WINDOW_SIZE);
 
@@ -91,15 +98,19 @@
 		return -EIO;
 	}
 	mymtd = do_map_probe("cfi_probe", &physmap_map);
-	if (mymtd) {
-		mymtd->module = THIS_MODULE;
-
-		add_mtd_device(mymtd);
-		return 0;
+	if (!mymtd) {
+		iounmap((void *)physmap_map.map_priv_1);
+		return -ENXIO;
 	}
-
-	iounmap((void *)physmap_map.map_priv_1);
-	return -ENXIO;
+	mymtd->module = THIS_MODULE;
+	add_mtd_device(mymtd);
+#if defined(CONFIG_MTD_PARTT_PARTS)
+	nrparts = parse_partt_partitions(mymtd, &parts);
+	if (nrparts <= 0)
+		return nrparts; /* FIXME: Is there more cleanup to do? */
+	add_mtd_partitions(mymtd, parts, nrparts);
+#endif
+	return 0;
 }
 
 static void __exit cleanup_physmap(void)
diff -Naur mtd.orig/drivers/mtd/partt.c mtd/drivers/mtd/partt.c
--- mtd.orig/drivers/mtd/partt.c	Thu Jan  1 01:00:00 1970
+++ mtd/drivers/mtd/partt.c	Tue Sep 25 20:22:03 2001
@@ -0,0 +1,117 @@
+/*
+ * partt Partition Table Parser
+ *
+ * very minimal and flexible parser
+ *
+ * Copyright (C) 2001 Joern Engel
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/string.h>
+#include <linux/mtd/partt.h>
+
+/*
+ * Atomic wrapper for (struct mtdinfo)->read, so it always returns len bytes
+ * or fails completely 
+ */
+inline int wrapped_read(struct mtd_info *mtd, loff_t from, size_t len, u_char *buf)
+{
+	int ret;
+	size_t retlen, offset;
+	for (retlen=offset=0; offset < len; offset += retlen) {
+		ret = mtd->read (mtd, from, len, &retlen, buf+offset);
+		if (ret<0)
+			return ret;
+		if (retlen==0)
+			return -EIO;
+	}
+	return ret;
+}
+
+#ifdef CONFIG_MTD_PARTT_SEEK_FROM_END
+#	define ADDR (master->size - (CONFIG_MTD_PARTT_ADDRESS))
+#else
+#	define ADDR (CONFIG_MTD_PARTT_ADDRESS)
+#endif
+
+/*
+ * Partition table format:
+ * - <=16 Entries on a table
+ * - Null-terminated - the last entry's name starts with 0x00
+ * - Extendable - the terminating entry might include a pointer to the next
+ *     partition table, even though this feature is not used yet
+ * - Small flash footprint - includes only informations that the kernel uses
+ *
+ * TODO: 
+ * Handle multiple partition tables
+ * Change code to handle flash sizes >4GiB
+ */
+int parse_partt_partitions(struct mtd_info *master, struct mtd_partition **pparts)
+{
+	int ret;
+	u32 flash_table;
+	partt_table *mem_table;
+	struct mtd_partition *parts;
+	int nrparts = 0;
+	char *names;
+	int namelen = 0;
+	int i;
+
+	/* get position of partition table */ 
+#ifdef CONFIG_MTD_PARTT_INDIRECT
+	ret = wrapped_read (master, ADDR, sizeof(flash_table), (u_char*)&flash_table);
+	if (ret<0)
+		return ret;
+	if (flash_table >= (master->size - TABLE_SIZE))
+		return -EFAULT;
+#else
+	flash_table = ADDR;
+#endif
+	/* copy partition table to ram */
+	mem_table = kmalloc (sizeof(partt_table), GFP_KERNEL);
+	if (!mem_table)
+		return -ENOMEM;
+	ret = wrapped_read (master, flash_table, TABLE_SIZE, (u_char*)mem_table);
+	if (ret<0)
+		goto out;
+	if (mem_table[0][TABLE_NO_ENTRIES-1].mask_flags != PARTT_MAGIC)
+		goto out;
+
+	/* calculate number of partitions and memory need */
+	for (; mem_table[0][nrparts].name[0] && nrparts<TABLE_NO_ENTRIES; nrparts++) {
+		if (mem_table[0][nrparts].name[NAME_MAX_LEN])
+			goto out;
+		/* FIXME: Do some more sanity checks */
+		namelen += strlen (mem_table[0][nrparts].name) + 1;
+	}
+	if (!nrparts) {
+		ret = 0;
+		goto out;
+	}
+
+	/* copy data to linux partition table */
+	parts = kmalloc (nrparts*sizeof(*parts) + namelen, GFP_KERNEL);
+	if (!parts) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	names = (char*)&parts[nrparts];
+	for (i=0; i<nrparts; i++) {
+		parts[i].size = mem_table[0][i].size;
+		parts[i].offset = mem_table[0][i].offset;
+		parts[i].mask_flags = mem_table[0][i].mask_flags;
+		parts[i].name = names;
+		strcpy (names, mem_table[0][i].name);
+		names += strlen(names)+1;
+	}
+	*pparts = parts;
+	ret = nrparts;
+out:
+	kfree (mem_table);
+	return ret;
+}
diff -Naur mtd.orig/include/linux/mtd/partt.h mtd/include/linux/mtd/partt.h
--- mtd.orig/include/linux/mtd/partt.h	Thu Jan  1 01:00:00 1970
+++ mtd/include/linux/mtd/partt.h	Tue Sep 25 20:15:02 2001
@@ -0,0 +1,28 @@
+#ifndef _LINUX_MTD_PARTT_H
+#define _LINUX_MTD_PARTT_H
+
+#include <linux/types.h>
+
+#define PARTT_MAGIC 0x0054544a /* "\0TTJ" */
+
+#define TABLE_ENTRY_SIZE (32)
+#define TABLE_NO_ENTRIES (16)
+#define TABLE_SIZE ((TABLE_NO_ENTRIES)*(TABLE_ENTRY_SIZE))
+#define NAME_MAX_LEN ((TABLE_ENTRY_SIZE) - 3*sizeof(__u32))
+
+#ifndef PARTT_NODEBUG
+#	ifdef __KERNEL__
+#		define DOUT(fmt, args...) printk(KERN_CRIT "partt: " fmt, ## args)
+#	endif
+#endif
+
+struct partt_entry {
+	char name[NAME_MAX_LEN]; /* name is also padding */
+	__u32 size;
+	__u32 offset;
+	__u32 mask_flags; 
+};
+
+typedef struct partt_entry partt_table[TABLE_NO_ENTRIES];
+
+#endif
diff -Naur mtd.orig/util/Makefile mtd/util/Makefile
--- mtd.orig/util/Makefile	Thu Sep  6 00:00:07 2001
+++ mtd/util/Makefile	Tue Sep 25 20:15:37 2001
@@ -7,7 +7,7 @@
 
 TARGETS = ftl_format erase eraseall nftldump nanddump doc_loadbios \
 nftl_format mkfs.jffs ftl_check nandtest nandwrite mkfs.jffs2 lock unlock \
-einfo mtd_debug fcp jffs2reader
+einfo mtd_debug fcp jffs2reader mkpartt
 
 SYMLINKS = crc32.h crc32.c compr_rtime.c compr_rubin.c compr.c pushpull.c pushpull.h histo_mips.h compr_rubin.h
 
diff -Naur mtd.orig/util/Makefile.am mtd/util/Makefile.am
--- mtd.orig/util/Makefile.am	Tue Jun 26 10:26:53 2001
+++ mtd/util/Makefile.am	Tue Sep 25 20:15:48 2001
@@ -2,7 +2,7 @@
 
 sbin_PROGRAMS = ftl_format erase eraseall nftldump nanddump doc_loadbios \
                nftl_format mkfs.jffs ftl_check nandtest nandwrite mkfs.jffs2 \
-	       lock unlock einfo mtd_debug fcp
+	       lock unlock einfo mtd_debug fcp mkpartt
 
 CFLAGS = -O2 -Wall
 INCLUDES = -I@CONFIG_KERNELDIR@/include -I@CONFIG_KERNELDIR@/fs/jffs2
diff -Naur mtd.orig/util/mkfs.jffs2.c mtd/util/mkfs.jffs2.c
--- mtd.orig/util/mkfs.jffs2.c	Mon Sep 10 00:00:15 2001
+++ mtd/util/mkfs.jffs2.c	Tue Sep 25 20:12:28 2001
@@ -22,7 +22,7 @@
 
 //#define DMALLOC
 //#define debug_msg	error_msg
-#define debug_msg(...)	{ }
+#define debug_msg(args...)	{ }
 
 
 #define _GNU_SOURCE
diff -Naur mtd.orig/util/mkpartt.c mtd/util/mkpartt.c
--- mtd.orig/util/mkpartt.c	Thu Jan  1 01:00:00 1970
+++ mtd/util/mkpartt.c	Tue Sep 25 20:15:58 2001
@@ -0,0 +1,122 @@
+/*
+ * TODO: 
+ * Always write partition table in big endian format
+ * Allow for multiple partition tables
+ */
+#include <stdio.h>
+#include <unistd.h>
+#define _GNU_SOURCE
+#include <getopt.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include "/usr/src/linux/include/linux/mtd/ibmpartt.h"
+
+#define MAX_BUF (4096)
+
+static int cross_endian = 0;
+
+void print_help ()
+{
+	printf ("\n"
+			"mkpartt\n"
+			"creates partt style flash partition tables\n"
+			"\n"
+			"Options:\n"
+			" -h --help          print this help\n"
+			" -c --cross-endian  write partition table in big enian on little endian machines or vice versa\n"
+			"\n"
+			);
+}
+
+void x_order_32 (__u32 *old32)
+{
+	__u32 new32;
+	__u8 *new8 = (__u8*)&new32;
+	__u8 *old8 = (__u8*)old32;
+	new8[0] = old8[3];
+	new8[1] = old8[2];
+	new8[2] = old8[1];
+	new8[3] = old8[0];
+	*old32 = new32;
+}
+
+int cross_endianize (partt_table *table)
+{
+	int i;
+	for (i=0; i<TABLE_NO_ENTRIES; i++) {
+		x_order_32 (&(table[0][i].size));
+		x_order_32 (&(table[0][i].offset));
+		x_order_32 (&(table[0][i].mask_flags));
+	}
+	return 0;
+}
+
+int parse_table (FILE *infile, FILE *outfile)
+{
+	partt_table table;
+	int entry;
+	char *buf;
+	int ret = 0;
+
+	__bzero ((char*)&table, sizeof(table));
+
+	buf = malloc (MAX_BUF); /* FIXME */
+	entry = 0;
+	while (fgets (buf, MAX_BUF, infile) && entry<TABLE_NO_ENTRIES-1) {
+		int columns;
+		if (buf[0] == '#')
+			continue;
+		columns = sscanf (buf, " %20s %x %x %x", /* FIXME: Replace 20 with NAME_MAX_LEN */
+			       	table[entry].name,
+			       	&(table[entry].size),
+			       	&(table[entry].offset),
+			       	&(table[entry].mask_flags));
+		if (columns < 3) {
+			ret = -EIO;
+			goto out;
+		}
+		if (columns == 3) /* mask_flags may be left empty */
+			table[entry].mask_flags = 0;
+		entry++;
+	}
+	__bzero (&(table[entry]), TABLE_ENTRY_SIZE);
+	table[TABLE_NO_ENTRIES-1].mask_flags = PARTT_MAGIC;
+
+	if (cross_endian)
+		cross_endianize (&table);
+
+	if (!fwrite (&table, TABLE_SIZE, 1, outfile))
+		ret = -EIO;
+out:
+	free (buf);
+	return ret;
+}
+
+int main (int argc, char** argv)
+{
+	while (1) {
+		int c, option_index;
+		char short_options[] = "ch";
+		static struct option long_options [] = {
+			{"cross-endian", 0, 0, 'c'},
+			{"help", 0, 0, 'h'},
+			{0, 0, 0, 0} /* FIXME: Parse some useful parameters */
+		};
+                c = getopt_long(argc, argv, short_options, long_options, &option_index);
+		if (c==-1)
+			break;
+		switch (c) {
+			case 'c':
+				cross_endian = 1;
+				break;
+			case 'h':
+				print_help ();
+				return 0;
+			default: 
+				printf ("Option not implemented, contact developer\n");
+		}
+	}
+	return parse_table (stdin, stdout);
+}

Re: partt partition table parser

[David Woodhouse]

In general, it looks relatively sane. Can you justify the use of 
CONFIG_MTD_PARTT_INDIRECT? 

What systems use this partition table format?


> +++ mtd/util/mkpartt.c	Tue Sep 25 20:15:58 2001
> +#include "/usr/src/linux/include/linux/mtd/ibmpartt.h"

No. Pull the definitions into the C file or take a copy. Don't look too 
hard at the mkfs.jffs2 code - do as I say, not as I do :)

> +void x_order_32 (__u32 *old32)
> +{
> +	__u32 new32;
> +	__u8 *new8 = (__u8*)&new32;
> +	__u8 *old8 = (__u8*)old32;
> +	new8[0] = old8[3];
> +	new8[1] = old8[2];
> +	new8[2] = old8[1];
> +	new8[3] = old8[0];
> +	*old32 = new32;
> +}

That's going to break. In the kernel, we compile with -fno-strict-aliasing 
just because we've always had evil code there and nobody's yet looked too 
hard at cleaning it up. For userspace, we need to write real C code.

> +		columns = sscanf (buf, " %20s %x %x %x", /* FIXME: Replace 20 with NAME_MAX_LEN */

 "%" #NAME_MAX_LEN "s %x %x %x"

How about making big-endian and little-endian options too, instead of just 
cross-endian?

--
dwmw2

Re: partt partition table parser

[Jörn Engel]

Hi!

> In general, it looks relatively sane. Can you justify the use of 
> CONFIG_MTD_PARTT_INDIRECT? 

During development, this makes it easier to move the partition table
around without recompiling the kernel. I might get rid of it if i
find/someone shows me a better solution. But work is still in
progress, even if the parser is already useable (and used).

> > +++ mtd/util/mkpartt.c	Tue Sep 25 20:15:58 2001
> > +#include "/usr/src/linux/include/linux/mtd/ibmpartt.h"
> 
> No. Pull the definitions into the C file or take a copy. Don't look too 
> hard at the mkfs.jffs2 code - do as I say, not as I do :)

That was a relic I missed. Fixed it now.

> > +void x_order_32 (__u32 *old32)
> > +{
> > +	__u32 new32;
> > +	__u8 *new8 = (__u8*)&new32;
> > +	__u8 *old8 = (__u8*)old32;
> > +	new8[0] = old8[3];
> > +	new8[1] = old8[2];
> > +	new8[2] = old8[1];
> > +	new8[3] = old8[0];
> > +	*old32 = new32;
> > +}
> 
> That's going to break. In the kernel, we compile with -fno-strict-aliasing 
> just because we've always had evil code there and nobody's yet looked too 
> hard at cleaning it up. For userspace, we need to write real C code.

True. I was still unaware of the correct way to handle endianness. Now
the partition table is big endian. Always. It feel good to reduce
error possibilities. :)

> > +		columns = sscanf (buf, " %20s %x %x %x", /* FIXME: Replace 20 with NAME_MAX_LEN */
> 
>  "%" #NAME_MAX_LEN "s %x %x %x"

It was a little more complicated than that. See the c faq.
http://www.eskimo.com/~scs/C-faq/q11.17.html

> How about making big-endian and little-endian options too, instead of just 
> cross-endian?

I chose a different approach (see above) that will cost some
nanoseconds on little endian machines but saves some people minutes
and hours by not messing up endianness again. Any objections?

The new patch can be found here:
http://wh.fh-wedel.de/~joern/software/kernel/partt.patch

Jörn

-- 
ticks = jiffies;
while (ticks == jiffies);
ticks = jiffies;
-- /usr/src/linux/init/main.c