tools/lib/str_error_r.c

   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  */
  20 char *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 }