mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-15 16:24:13 +08:00
0a9df786a6
This adds kvasprintf_const which tries to use kstrdup_const if possible: If the format string contains no % characters, or if the format string is exactly "%s", we delegate to kstrdup_const. Otherwise, we fall back to kvasprintf. Just as for kstrdup_const, the main motivation is to save memory by reusing .rodata when possible. The return value should be freed by kfree_const, just like for kstrdup_const. There is deliberately no kasprintf_const: In the vast majority of cases, the format string argument is a literal, so one can determine statically whether one could instead use kstrdup_const directly (which would also require one to change all corresponding kfree calls to kfree_const). Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
62 lines
1.2 KiB
C
62 lines
1.2 KiB
C
/*
|
|
* linux/lib/kasprintf.c
|
|
*
|
|
* Copyright (C) 1991, 1992 Linus Torvalds
|
|
*/
|
|
|
|
#include <stdarg.h>
|
|
#include <linux/export.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/types.h>
|
|
#include <linux/string.h>
|
|
|
|
/* Simplified asprintf. */
|
|
char *kvasprintf(gfp_t gfp, const char *fmt, va_list ap)
|
|
{
|
|
unsigned int len;
|
|
char *p;
|
|
va_list aq;
|
|
|
|
va_copy(aq, ap);
|
|
len = vsnprintf(NULL, 0, fmt, aq);
|
|
va_end(aq);
|
|
|
|
p = kmalloc_track_caller(len+1, gfp);
|
|
if (!p)
|
|
return NULL;
|
|
|
|
vsnprintf(p, len+1, fmt, ap);
|
|
|
|
return p;
|
|
}
|
|
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;
|
|
char *p;
|
|
|
|
va_start(ap, fmt);
|
|
p = kvasprintf(gfp, fmt, ap);
|
|
va_end(ap);
|
|
|
|
return p;
|
|
}
|
|
EXPORT_SYMBOL(kasprintf);
|