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Commit 7db6f5fb authored by Joe Perches's avatar Joe Perches Committed by David S. Miller
Browse files

vsprintf: Recursive vsnprintf: Add "%pV", struct va_format 



Add the ability to print a format and va_list from a structure pointer

Allows __dev_printk to be implemented as a single printk while
minimizing string space duplication.

%pV should not be used without some mechanism to verify the
format and argument use ala __attribute__(format (printf(...))).

Signed-off-by: default avatarJoe Perches <joe@perches.com>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e490c1de

include/linux/kernel.h

+5 −0
Original line number Diff line number Diff line
@@ -171,6 +171,11 @@ static inline void might_fault(void) 
}

#endif



struct va_format {

	const char *fmt;

	va_list *va;

};



extern struct atomic_notifier_head panic_notifier_list;

extern long (*panic_blink)(long time);

NORET_TYPE void panic(const char * fmt, ...)

lib/vsprintf.c

+9 −0
Original line number Diff line number Diff line
@@ -980,6 +980,11 @@ char *uuid_string(char *buf, char *end, const u8 *addr, 
 *             [0][1][2][3]-[4][5]-[6][7]-[8][9]-[10][11][12][13][14][15]

 *           little endian output byte order is:

 *             [3][2][1][0]-[5][4]-[7][6]-[8][9]-[10][11][12][13][14][15]

 * - 'V' For a struct va_format which contains a format string * and va_list *,

 *       call vsnprintf(->format, *->va_list).

 *       Implements a "recursive vsnprintf".

 *       Do not use this feature without some mechanism to verify the

 *       correctness of the format string and va_list arguments.

 *

 * Note: The difference between 'S' and 'F' is that on ia64 and ppc64

 * function pointers are really function descriptors, which contain a
@@ -1025,6 +1030,10 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, 
		break;

	case 'U':

		return uuid_string(buf, end, ptr, spec, fmt);

	case 'V':

		return buf + vsnprintf(buf, end - buf,

				       ((struct va_format *)ptr)->fmt,

				       *(((struct va_format *)ptr)->va));

	}

	spec.flags |= SMALL;

	if (spec.field_width == -1) {