Patchwork [1/4] printk: add %I4, %I6, %i4, %i6 format specifiers

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Submitter Harvey Harrison
Date Oct. 29, 2008, 6:35 p.m.
Message ID <1225305340.5688.36.camel@brick>
Download mbox | patch
Permalink /patch/6294/
State Accepted
Delegated to: David Miller
Headers show

Comments

Harvey Harrison - Oct. 29, 2008, 6:35 p.m.
For use in printing IPv4, or IPv6 addresses in the usual way:

%i4 and %I4 are currently equivalent and print the address in
dot-separated decimal x.x.x.x

%I6 prints 16-bit network order hex with colon separators:
xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx

%i6 omits the colons.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
---
 lib/vsprintf.c |   31 +++++++++++++++++++++++++++++++
 1 files changed, 31 insertions(+), 0 deletions(-)
David Miller - Oct. 29, 2008, 8:04 p.m.
From: Harvey Harrison <harvey.harrison@gmail.com>
Date: Wed, 29 Oct 2008 11:35:40 -0700

> For use in printing IPv4, or IPv6 addresses in the usual way:
> 
> %i4 and %I4 are currently equivalent and print the address in
> dot-separated decimal x.x.x.x
> 
> %I6 prints 16-bit network order hex with colon separators:
> xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx
> 
> %i6 omits the colons.
> 
> Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>

Applied.
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Joe Perches - Oct. 30, 2008, 8:28 p.m.
On Wed, 2008-10-29 at 11:35 -0700, Harvey Harrison wrote:
> For use in printing IPv4, or IPv6 addresses in the usual way:
> Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
> ---
>  lib/vsprintf.c |   31 +++++++++++++++++++++++++++++++
>  1 files changed, 31 insertions(+), 0 deletions(-)
> 
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index cb5bc04..a863006 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
[]
> @@ -650,6 +671,16 @@ static char *pointer(const char *fmt, char *buf, char *end, void *ptr, int field
>  		return mac_address_string(buf, end, ptr, field_width, precision, flags);
>  	case '6':
>  		return ip6_addr_string(buf, end, ptr, field_width, precision, flags);
> +	case 'i':
> +		flags |= SPECIAL;
> +		/* Fallthrough */
> +	case 'I':
> +		if (fmt[1] == '6')
> +			return ip6_addr_string(buf, end, ptr, field_width, precision, flags);
> +		if (fmt[1] == '4')
> +			return ip4_addr_string(buf, end, ptr, field_width, precision, flags);
> +		flags &= ~SPECIAL;
> +		break;
>  	}
>  	flags |= SMALL;
>  	if (field_width == -1) {

Hi Harvey.

I was thinking about extending %p<foo> to support
struct task_struct * and noticed this code isn't
really correct.

SPECIAL should be cleared from flags only when *fmt
is 'i' not 'I' and SPECIAL wasn't previously set.

cheers, Joe

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Harvey Harrison - Oct. 30, 2008, 11:59 p.m.
On Thu, 2008-10-30 at 13:28 -0700, Joe Perches wrote:
> On Wed, 2008-10-29 at 11:35 -0700, Harvey Harrison wrote:
> >  		return ip6_addr_string(buf, end, ptr, field_width, precision, flags);
> > +	case 'i':
> > +		flags |= SPECIAL;
> > +		/* Fallthrough */
> > +	case 'I':
> > +		if (fmt[1] == '6')
> > +			return ip6_addr_string(buf, end, ptr, field_width, precision, flags);
> > +		if (fmt[1] == '4')
> > +			return ip4_addr_string(buf, end, ptr, field_width, precision, flags);
> > +		flags &= ~SPECIAL;
> > +		break;
> >  	}
> >  	flags |= SMALL;
> >  	if (field_width == -1) {
> 
> Hi Harvey.
> 
> I was thinking about extending %p<foo> to support
> struct task_struct * and noticed this code isn't
> really correct.
> 
> SPECIAL should be cleared from flags only when *fmt
> is 'i' not 'I' and SPECIAL wasn't previously set.
> 

SPECIAL is set when # is used with the p modifier...which warns as we've
already seen.  So the only way to set special in the %p case is to use
i.  Instead of having an if() I just unconditionally clear it (perhaps
unnecessarily).  Mind you, we only get here if you pass in %p[iI][not 4 or 6]

Cheers,

Harvey

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Patch

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index cb5bc04..a863006 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -616,6 +616,23 @@  static char *ip6_addr_string(char *buf, char *end, u8 *addr, int field_width,
 	return string(buf, end, ip6_addr, field_width, precision, flags & ~SPECIAL);
 }
 
+static char *ip4_addr_string(char *buf, char *end, u8 *addr, int field_width,
+			 int precision, int flags)
+{
+	char ip4_addr[4 * 4]; /* (4 * 3 decimal digits), 3 dots and trailing zero */
+	char *p = ip4_addr;
+	int i;
+
+	for (i = 0; i < 4; i++) {
+		p = put_dec_trunc(p, addr[i]);
+		if (i != 3)
+			*p++ = '.';
+	}
+	*p = '\0';
+
+	return string(buf, end, ip4_addr, field_width, precision, flags & ~SPECIAL);
+}
+
 /*
  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
  * by an extra set of alphanumeric characters that are extended format
@@ -629,6 +646,10 @@  static char *ip6_addr_string(char *buf, char *end, u8 *addr, int field_width,
  *       addresses (not the name nor the flags)
  * - 'M' For a 6-byte MAC address, it prints the address in the
  *       usual colon-separated hex notation
+ * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way (dot-separated
+ *       decimal for v4 and colon separated network-order 16 bit hex for v6)
+ * - 'i' [46] for 'raw' IPv4/IPv6 addresses, IPv6 omits the colons, IPv4 is
+         currently the same
  * - '6' For a IPv6 address prints the address in network-ordered 16 bit hex
  *       with colon separators
  *
@@ -650,6 +671,16 @@  static char *pointer(const char *fmt, char *buf, char *end, void *ptr, int field
 		return mac_address_string(buf, end, ptr, field_width, precision, flags);
 	case '6':
 		return ip6_addr_string(buf, end, ptr, field_width, precision, flags);
+	case 'i':
+		flags |= SPECIAL;
+		/* Fallthrough */
+	case 'I':
+		if (fmt[1] == '6')
+			return ip6_addr_string(buf, end, ptr, field_width, precision, flags);
+		if (fmt[1] == '4')
+			return ip4_addr_string(buf, end, ptr, field_width, precision, flags);
+		flags &= ~SPECIAL;
+		break;
 	}
 	flags |= SMALL;
 	if (field_width == -1) {