vfork.S 2.2 KB

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  1. /* Copyright (C) 1999, 2002, 2003 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. Contributed by Andreas Schwab <schwab@gnu.org>.
  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. The GNU C Library is distributed in the hope that it will be useful,
  9. but WITHOUT ANY WARRANTY; without even the implied warranty of
  10. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11. Lesser General Public License for more details.
  12. You should have received a copy of the GNU Lesser General Public
  13. License along with the GNU C Library; if not, write to the Free
  14. Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  15. 02111-1307 USA. */
  16. #include <sysdep-cancel.h>
  17. #define _ERRNO_H 1
  18. #include <bits/errno.h>
  19. #include <bits/kernel-features.h>
  20. /* Clone the calling process, but without copying the whole address space.
  21. The calling process is suspended until the new process exits or is
  22. replaced by a call to `execve'. Return -1 for errors, 0 to the new process,
  23. and the process ID of the new process to the old process. */
  24. ENTRY (__vfork)
  25. #ifdef SHARED
  26. tstl (__libc_pthread_functions@GOTPC, %pc)
  27. #else
  28. .weak pthread_create
  29. movel #pthread_create, %d0
  30. #endif
  31. jbne HIDDEN_JUMPTARGET (fork)
  32. #ifdef __NR_vfork
  33. /* Pop the return PC value into A0. */
  34. movel %sp@+, %a0
  35. /* Stuff the syscall number in D0 and trap into the kernel. */
  36. movel #SYS_ify (vfork), %d0
  37. trap #0
  38. tstl %d0
  39. jmi .Lerror /* Branch forward if it failed. */
  40. /* Jump to the return PC. */
  41. jmp %a0@
  42. .Lerror:
  43. /* Push back the return PC. */
  44. movel %a0,%sp@-
  45. # ifdef __ASSUME_VFORK_SYSCALL
  46. # ifndef __PIC__
  47. jbra SYSCALL_ERROR_LABEL
  48. # endif
  49. # else
  50. /* Check if vfork syscall is known at all. */
  51. movel #-ENOSYS,%d1
  52. cmpl %d0,%d1
  53. jne SYSCALL_ERROR_LABEL
  54. # endif
  55. #endif
  56. #ifndef __ASSUME_VFORK_SYSCALL
  57. /* If we don't have vfork, fork is close enough. */
  58. movel #SYS_ify (fork), %d0
  59. trap #0
  60. tstl %d0
  61. jmi SYSCALL_ERROR_LABEL
  62. rts
  63. #endif
  64. PSEUDO_END (__vfork)
  65. libc_hidden_def (__vfork)
  66. weak_alias (__vfork, vfork)