tools/lib/str_error_r.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #undef _GNU_SOURCE
   3 #include <string.h>
   4 #include <stdio.h>
   5 #include <linux/string.h>
   6
   7 /*
   8  * The tools so far have been using the strerror_r() GNU variant, that returns
   9  * a string, be it the buffer passed or something else.
  10  *
  11  * But that, besides being tricky in cases where we expect that the function
  12  * using strerror_r() returns the error formatted in a provided buffer (we have
  13  * to check if it returned something else and copy that instead), breaks the
  14  * build on systems not using glibc, like Alpine Linux, where musl libc is
  15  * used.
  16  *
  17  * So, introduce yet another wrapper, str_error_r(), that has the GNU
  18  * interface, but uses the portable XSI variant of strerror_r(), so that users
  19  * rest asured that the provided buffer is used and it is what is returned.
  20  */
  21 char *str_error_r(int errnum, char *buf, size_t buflen)
  22 {
  23         int err = strerror_r(errnum, buf, buflen);
  24         if (err)
  25                 snprintf(buf, buflen, "INTERNAL ERROR: strerror_r(%d, [buf], %zd)=%d", errnum, buflen, err);
  26         return buf;
  27 }