vfork.S 1.9 KB

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  1. /* Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. The GNU C Library is free software; you can redistribute it and/or
  4. modify it under the terms of the GNU Lesser General Public
  5. License as published by the Free Software Foundation; either
  6. version 2.1 of the License, or (at your option) any later version.
  7. The GNU C Library is distributed in the hope that it will be useful,
  8. but WITHOUT ANY WARRANTY; without even the implied warranty of
  9. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  10. Lesser General Public License for more details.
  11. You should have received a copy of the GNU Lesser General Public
  12. License along with the GNU C Library; if not, see
  13. <http://www.gnu.org/licenses/>. */
  14. #include <sysdep-cancel.h>
  15. #define _ERRNO_H 1
  16. #include <bits/errno.h>
  17. /* Clone the calling process, but without copying the whole address space.
  18. The calling process is suspended until the new process exits or is
  19. replaced by a call to `execve'. Return -1 for errors, 0 to the new process,
  20. and the process ID of the new process to the old process. */
  21. ENTRY (__vfork)
  22. #ifdef SHARED
  23. cmpq $0, __libc_pthread_functions(%rip)
  24. #else
  25. .weak pthread_create
  26. movq $pthread_create, %rax
  27. testq %rax, %rax
  28. #endif
  29. jne HIDDEN_JUMPTARGET (fork)
  30. /* Pop the return PC value into RDI. We need a register that
  31. is preserved by the syscall and that we're allowed to destroy. */
  32. popq %rdi
  33. cfi_adjust_cfa_offset(-8)
  34. /* Stuff the syscall number in RAX and enter into the kernel. */
  35. movl $SYS_ify (vfork), %eax
  36. syscall
  37. /* Push back the return PC. */
  38. pushq %rdi
  39. cfi_adjust_cfa_offset(8)
  40. cmpl $-4095, %eax
  41. jae SYSCALL_ERROR_LABEL /* Branch forward if it failed. */
  42. /* Normal return. */
  43. .Lpseudo_end:
  44. ret
  45. PSEUDO_END (__vfork)
  46. libc_hidden_def (__vfork)
  47. weak_alias (__vfork, vfork)