vsprintf: fix bug in negative value printing (39e874f8) · Commits · 戴 / test

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

Sitsofe Wheeler <sitsofe@yahoo.com> Signed-off-by:

Frederic 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:

Ingo Molnar <mingo@elte.hu>

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 @@ qualifier:

		case 'd':
		case 'i':
		sign = true;
		spec->flags \|= SIGN;
		case 'u':
		break;

		@@ -912,7 +911,7 @@ qualifier:
		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 @@ qualifier:
		} 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);

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