sysdeps/x86/longjmp.c

   1 /* __libc_siglongjmp for x86.
   2    Copyright (C) 2018-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #define __libc_longjmp __redirect___libc_longjmp
  20 #include <setjmp/longjmp.c>
  21 #undef __libc_longjmp
  22
  23 extern void __longjmp_cancel (__jmp_buf __env, int __val)
  24      __attribute__ ((__noreturn__)) attribute_hidden;
  25
  26 /* Since __libc_longjmp is a private interface for cancellation
  27    implementation in libpthread, there is no need to restore shadow
  28    stack register.  */
  29
  30 void
  31 __libc_longjmp (sigjmp_buf env, int val)
  32 {
  33   /* Perform any cleanups needed by the frames being unwound.  */
  34   _longjmp_unwind (env, val);
  35
  36   if (env[0].__mask_was_saved)
  37     /* Restore the saved signal mask.  */
  38     (void) __sigprocmask (SIG_SETMASK,
  39                           (sigset_t *) &env[0].__saved_mask,
  40                           (sigset_t *) NULL);
  41
  42   /* Call the machine-dependent function to restore machine state
  43      without shadow stack.  */
  44   __longjmp_cancel (env[0].__jmpbuf, val ?: 1);
  45 }