diff options
| -rw-r--r-- | include/linux/kernel.h | 2 | ||||
| -rw-r--r-- | lib/kasprintf.c | 16 |
2 files changed, 18 insertions, 0 deletions
diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 5582410727cb..2c13f747ac2e 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -413,6 +413,8 @@ extern __printf(2, 3) char *kasprintf(gfp_t gfp, const char *fmt, ...); extern __printf(2, 0) char *kvasprintf(gfp_t gfp, const char *fmt, va_list args); +extern __printf(2, 0) +const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args); extern __scanf(2, 3) int sscanf(const char *, const char *, ...); diff --git a/lib/kasprintf.c b/lib/kasprintf.c index 32f12150fc4f..f194e6e593e1 100644 --- a/lib/kasprintf.c +++ b/lib/kasprintf.c @@ -31,6 +31,22 @@ char *kvasprintf(gfp_t gfp, const char *fmt, va_list ap) } EXPORT_SYMBOL(kvasprintf); +/* + * If fmt contains no % (or is exactly %s), use kstrdup_const. If fmt + * (or the sole vararg) points to rodata, we will then save a memory + * allocation and string copy. In any case, the return value should be + * freed using kfree_const(). + */ +const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list ap) +{ + if (!strchr(fmt, '%')) + return kstrdup_const(fmt, gfp); + if (!strcmp(fmt, "%s")) + return kstrdup_const(va_arg(ap, const char*), gfp); + return kvasprintf(gfp, fmt, ap); +} +EXPORT_SYMBOL(kvasprintf_const); + char *kasprintf(gfp_t gfp, const char *fmt, ...) { va_list ap; |