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Date:      Thu, 3 Apr 2014 15:45:55 +1100 (EST)
From:      Bruce Evans <brde@optusnet.com.au>
To:        Xin LI <delphij@freebsd.org>
Cc:        svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org
Subject:   Re: svn commit: r264059 - head/bin/dd
Message-ID:  <20140403150420.H959@besplex.bde.org>
In-Reply-To: <201404030055.s330tGCI070764@svn.freebsd.org>
References:  <201404030055.s330tGCI070764@svn.freebsd.org>

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On Thu, 3 Apr 2014, Xin LI wrote:

> Log:
>  Implement GNU's extension of 'status' operand.  The GNU syntax is
>  borrowed where syntax status=noxfer means no transfer statistics
>  and status=none means no status information at all.
>
>  This feature is useful because the statistics information can
>  sometimes be annoying, and redirecting stderr to /dev/null would
>  mean error messages also gets silenced.
>
>  Obtained from:	OpenBSD
>  MFC after:	2 weeks
> ...
> Modified: head/bin/dd/dd.h
> ==============================================================================
> --- head/bin/dd/dd.h	Wed Apr  2 23:07:15 2014	(r264058)
> +++ head/bin/dd/dd.h	Thu Apr  3 00:55:16 2014	(r264059)
> @@ -68,32 +68,35 @@ typedef struct {
> } STAT;
>
> /* Flags (in ddflags). */
> -#define	C_ASCII		0x00001
> -#define	C_BLOCK		0x00002

The table should have been reformatted separately, or better not at all.

> -#define	C_BS		0x00004
> -#define	C_CBS		0x00008
> -#define	C_COUNT		0x00010
> -#define	C_EBCDIC	0x00020
> -#define	C_FILES		0x00040
> -#define	C_IBS		0x00080
> -#define	C_IF		0x00100
> -#define	C_LCASE		0x00200
> -#define	C_NOERROR	0x00400
> -#define	C_NOTRUNC	0x00800
> -#define	C_OBS		0x01000
> -#define	C_OF		0x02000
> -#define	C_OSYNC		0x04000
> -#define	C_PAREVEN	0x08000
> -#define	C_PARNONE	0x100000

The previous formatting was not too good, and obfuscated a bug here.
4 bits are unused.  Someone added this bug together with many others
in 2004, and I missed it then when I committed a fix for the others.
Most of the bugs that I fixed were unsorting of the table by adding
to its end.  Insertion sort tends to give large churn of the table by
changing all the numbers, but for the 2004 fix there wasn't much churn
except relative to the unsorted version because all the changes were
near the end.

> -#define	C_PARODD	0x200000
> -#define	C_PARSET	0x400000
> -#define	C_SEEK		0x800000
> -#define	C_SKIP		0x1000000
> -#define	C_SPARSE	0x2000000
> -#define	C_SWAB		0x4000000
> -#define	C_SYNC		0x8000000
> -#define	C_UCASE		0x10000000
> -#define	C_UNBLOCK	0x20000000
> -#define	C_FILL		0x40000000
> +#define	C_ASCII		0x000000001
> +#define	C_BLOCK		0x000000002
> +#define	C_BS		0x000000004
> +#define	C_CBS		0x000000008
> +#define	C_COUNT		0x000000010
> +#define	C_EBCDIC	0x000000020
> +#define	C_FILES		0x000000040
> +#define	C_IBS		0x000000080
> +#define	C_IF		0x000000100
> +#define	C_LCASE		0x000000200
> +#define	C_NOERROR	0x000000400
> +#define	C_NOTRUNC	0x000000800
> +#define	C_OBS		0x000001000
> +#define	C_OF		0x000002000
> +#define	C_OSYNC		0x000004000
> +#define	C_PAREVEN	0x000008000
> +#define	C_PARNONE	0x000100000
> +#define	C_PARODD	0x000200000
> +#define	C_PARSET	0x000400000
> +#define	C_SEEK		0x000800000
> +#define	C_SKIP		0x001000000
> +#define	C_SPARSE	0x002000000
> +#define	C_SWAB		0x004000000
> +#define	C_SYNC		0x008000000
> +#define	C_UCASE		0x010000000
> +#define	C_UNBLOCK	0x020000000

Unsorting of the table continued from here after I stopped policing the
order.

> +#define	C_FILL		0x040000000
> +#define	C_STATUS	0x080000000

The above 2 unsorted entries are old, but reformatting in this commit
obfuscates the change.

> +#define	C_NOXFER	0x100000000
> +#define	C_NOINFO	0x200000000

Latest unsorting.

The 2 values above UINT_MAX also won't compile with compilers that warn
that 'integer constant is too large for "long" type'.  Mainly gcc without
-std=c99.  clang is too incompatible to warn about this even with
-std=c89 -Wall.  The fix is not to further churn the table by adding
a ULL suffix to all entries.

>
> #define	C_PARITY	(C_PAREVEN | C_PARODD | C_PARNONE | C_PARSET)
>
> Modified: head/bin/dd/extern.h
> ==============================================================================
> --- head/bin/dd/extern.h	Wed Apr  2 23:07:15 2014	(r264058)
> +++ head/bin/dd/extern.h	Thu Apr  3 00:55:16 2014	(r264059)
> @@ -53,7 +53,7 @@ extern STAT st;
> extern void (*cfunc)(void);
> extern uintmax_t cpy_cnt;
> extern size_t cbsz;
> -extern u_int ddflags;
> +extern u_int64_t ddflags;

Not needed when the unused bits in the first 32 are used.  There are only
30 flags now.

> extern uintmax_t files_cnt;
> extern const u_char *ctab;
> extern const u_char a2e_32V[], a2e_POSIX[];
>

Bruce



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