Line data    Source code

       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. */
      15         369 : 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         369 :         va_copy(aq, ap);
      22         369 :         first = vsnprintf(NULL, 0, fmt, aq);
      23         369 :         va_end(aq);
      24             : 
      25         369 :         p = kmalloc_track_caller(first+1, gfp);
      26         369 :         if (!p)
      27             :                 return NULL;
      28             : 
      29         369 :         second = vsnprintf(p, first+1, fmt, ap);
      30         369 :         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             :  */
      43         747 : const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list ap)
      44             : {
      45         747 :         if (!strchr(fmt, '%'))
      46          11 :                 return kstrdup_const(fmt, gfp);
      47         736 :         if (!strcmp(fmt, "%s"))
      48         716 :                 return kstrdup_const(va_arg(ap, const char*), gfp);
      49          20 :         return kvasprintf(gfp, fmt, ap);
      50             : }
      51             : EXPORT_SYMBOL(kvasprintf_const);
      52             : 
      53          16 : char *kasprintf(gfp_t gfp, const char *fmt, ...)
      54             : {
      55             :         va_list ap;
      56             :         char *p;
      57             : 
      58          16 :         va_start(ap, fmt);
      59          16 :         p = kvasprintf(gfp, fmt, ap);
      60          16 :         va_end(ap);
      61             : 
      62          16 :         return p;
      63             : }
      64             : EXPORT_SYMBOL(kasprintf);