tools/lib/traceevent/tep_strerror.c

   1 // SPDX-License-Identifier: LGPL-2.1
   2 #undef _GNU_SOURCE
   3 #include <string.h>
   4 #include <stdio.h>
   5
   6 #include "event-parse.h"
   7
   8 #undef _PE
   9 #define _PE(code, str) str
  10 static const char * const tep_error_str[] = {
  11         TEP_ERRORS
  12 };
  13 #undef _PE
  14
  15 /*
  16  * The tools so far have been using the strerror_r() GNU variant, that returns
  17  * a string, be it the buffer passed or something else.
  18  *
  19  * But that, besides being tricky in cases where we expect that the function
  20  * using strerror_r() returns the error formatted in a provided buffer (we have
  21  * to check if it returned something else and copy that instead), breaks the
  22  * build on systems not using glibc, like Alpine Linux, where musl libc is
  23  * used.
  24  *
  25  * So, introduce yet another wrapper, str_error_r(), that has the GNU
  26  * interface, but uses the portable XSI variant of strerror_r(), so that users
  27  * rest asured that the provided buffer is used and it is what is returned.
  28  */
  29 int tep_strerror(struct tep_handle *tep __maybe_unused,
  30                  enum tep_errno errnum, char *buf, size_t buflen)
  31 {
  32         const char *msg;
  33         int idx;
  34
  35         if (!buflen)
  36                 return 0;
  37
  38         if (errnum >= 0) {
  39                 int err = strerror_r(errnum, buf, buflen);
  40                 buf[buflen - 1] = 0;
  41                 return err;
  42         }
  43
  44         if (errnum <= __TEP_ERRNO__START ||
  45             errnum >= __TEP_ERRNO__END)
  46                 return -1;
  47
  48         idx = errnum - __TEP_ERRNO__START - 1;
  49         msg = tep_error_str[idx];
  50         snprintf(buf, buflen, "%s", msg);
  51
  52         return 0;
  53 }