1  /* Restartable Sequences tests header.
       2     Copyright (C) 2021-2023 Free Software Foundation, Inc.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library; if not, see
      16     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include <errno.h>
      19  #include <error.h>
      20  #include <stdbool.h>
      21  #include <stdint.h>
      22  #include <support/check.h>
      23  #include <syscall.h>
      24  #include <sys/rseq.h>
      25  #include <tls.h>
      26  
      27  static inline bool
      28  rseq_thread_registered (void)
      29  {
      30    return THREAD_GETMEM_VOLATILE (THREAD_SELF, rseq_area.cpu_id) >= 0;
      31  }
      32  
      33  static inline int
      34  sys_rseq (struct rseq *rseq_abi, uint32_t rseq_len, int flags, uint32_t sig)
      35  {
      36    return syscall (__NR_rseq, rseq_abi, rseq_len, flags, sig);
      37  }
      38  
      39  static inline bool
      40  rseq_available (void)
      41  {
      42    int rc;
      43  
      44    rc = sys_rseq (NULL, 0, 0, 0);
      45    if (rc != -1)
      46      FAIL_EXIT1 ("Unexpected rseq return value %d", rc);
      47    switch (errno)
      48      {
      49      case ENOSYS:
      50        return false;
      51      case EINVAL:
      52        /* rseq is implemented, but detected an invalid rseq_len parameter.  */
      53        return true;
      54      default:
      55        FAIL_EXIT1 ("Unexpected rseq error %s", strerror (errno));
      56      }
      57  }