LXR linux/tools/lib/str_error

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