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Commit 39e874f8 authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar
Browse files

vsprintf: fix bug in negative value printing 



Sitsofe Wheeler found and bisected that while unifying the
vsprintf format decoding in:

  fef20d9c: vsprintf: unify the format decoding layer for its 3 users

The sign flag has been dropped out in favour of
precise types (ie: LONG/ULONG).

But the format helper number() still needs this flag to keep track of
the signedness unless it will consider all numbers as unsigned.

Also add an explicit cast to int (for %d) while parsing with va_arg()
to ensure the highest bit is well extended on the 64 bits number that
hosts the value in case of negative values.

Reported-Bisected-Tested-by: default avatarSitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <20090309201503.GA5010@nowhere>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent fef20d9c

lib/vsprintf.c

+6 −7
Original line number Diff line number Diff line
@@ -768,7 +768,6 @@ static char *pointer(const char *fmt, char *buf, char *end, void *ptr, 
static int format_decode(const char *fmt, struct printf_spec *spec)

{

	const char *start = fmt;

	bool sign = false;



	/* we finished early by reading the field width */

	if (spec->type == FORMAT_TYPE_WITDH) {
@@ -900,7 +899,7 @@ static int format_decode(const char *fmt, struct printf_spec *spec) 


	case 'd':

	case 'i':

		sign = true;

		spec->flags |= SIGN;

	case 'u':

		break;
@@ -912,7 +911,7 @@ static int format_decode(const char *fmt, struct printf_spec *spec) 
	if (spec->qualifier == 'L')

		spec->type = FORMAT_TYPE_LONG_LONG;

	else if (spec->qualifier == 'l') {

		if (sign)

		if (spec->flags & SIGN)

			spec->type = FORMAT_TYPE_LONG;

		else

			spec->type = FORMAT_TYPE_ULONG;
@@ -921,12 +920,12 @@ static int format_decode(const char *fmt, struct printf_spec *spec) 
	} else if (spec->qualifier == 't') {

		spec->type = FORMAT_TYPE_PTRDIFF;

	} else if (spec->qualifier == 'h') {

		if (sign)

		if (spec->flags & SIGN)

			spec->type = FORMAT_TYPE_SHORT;

		else

			spec->type = FORMAT_TYPE_USHORT;

	} else {

		if (sign)

		if (spec->flags & SIGN)

			spec->type = FORMAT_TYPE_INT;

		else

			spec->type = FORMAT_TYPE_UINT;
@@ -1101,8 +1100,8 @@ int vsnprintf(char *buf, size_t size, const char *fmt, va_list args) 
			case FORMAT_TYPE_SHORT:

				num = (short) va_arg(args, int);

				break;

			case FORMAT_TYPE_UINT:

				num = va_arg(args, unsigned int);

			case FORMAT_TYPE_INT:

				num = (int) va_arg(args, int);

				break;

			default:

				num = va_arg(args, unsigned int);