[PATCH 1/2] vsprintf: Recursive vsnprintf: Add "%pV", struct va_format
in [Kernel]
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From: Joe Perches on 4 Mar 2010 01:30 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: Joe Perches <joe(a)perches.com> --- include/linux/kernel.h | 5 +++++ lib/vsprintf.c | 9 +++++++++ 2 files changed, 14 insertions(+), 0 deletions(-) diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 7f07074..0eae8e9 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -169,6 +169,11 @@ 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, ...) diff --git a/lib/vsprintf.c b/lib/vsprintf.c index af4aaa6..0fd7f8b 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -950,6 +950,11 @@ static 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 @@ -994,6 +999,10 @@ static 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) { -- 1.7.0.14.g7e948 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |