xref: /openbmc/linux/lib/kasprintf.c (revision c0891ac1)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/lib/kasprintf.c
4  *
5  *  Copyright (C) 1991, 1992  Linus Torvalds
6  */
7 
8 #include <linux/stdarg.h>
9 #include <linux/export.h>
10 #include <linux/slab.h>
11 #include <linux/types.h>
12 #include <linux/string.h>
13 
14 /* Simplified asprintf. */
kvasprintf(gfp_t gfp,const char * fmt,va_list ap)15 char *kvasprintf(gfp_t gfp, const char *fmt, va_list ap)
16 {
17 	unsigned int first, second;
18 	char *p;
19 	va_list aq;
20 
21 	va_copy(aq, ap);
22 	first = vsnprintf(NULL, 0, fmt, aq);
23 	va_end(aq);
24 
25 	p = kmalloc_track_caller(first+1, gfp);
26 	if (!p)
27 		return NULL;
28 
29 	second = vsnprintf(p, first+1, fmt, ap);
30 	WARN(first != second, "different return values (%u and %u) from vsnprintf(\"%s\", ...)",
31 	     first, second, fmt);
32 
33 	return p;
34 }
35 EXPORT_SYMBOL(kvasprintf);
36 
37 /*
38  * If fmt contains no % (or is exactly %s), use kstrdup_const. If fmt
39  * (or the sole vararg) points to rodata, we will then save a memory
40  * allocation and string copy. In any case, the return value should be
41  * freed using kfree_const().
42  */
kvasprintf_const(gfp_t gfp,const char * fmt,va_list ap)43 const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list ap)
44 {
45 	if (!strchr(fmt, '%'))
46 		return kstrdup_const(fmt, gfp);
47 	if (!strcmp(fmt, "%s"))
48 		return kstrdup_const(va_arg(ap, const char*), gfp);
49 	return kvasprintf(gfp, fmt, ap);
50 }
51 EXPORT_SYMBOL(kvasprintf_const);
52 
kasprintf(gfp_t gfp,const char * fmt,...)53 char *kasprintf(gfp_t gfp, const char *fmt, ...)
54 {
55 	va_list ap;
56 	char *p;
57 
58 	va_start(ap, fmt);
59 	p = kvasprintf(gfp, fmt, ap);
60 	va_end(ap);
61 
62 	return p;
63 }
64 EXPORT_SYMBOL(kasprintf);
65