lib/kasprintf.c

   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);