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