io/dup2.s

   1 .text
   2 .globl __dup2
   3 .type __dup2,@function
   4 .align 1<<4
   5 __dup2:
   6         movl $33, %eax
   7         syscall
   8         cmpq $-4095, %rax
   9         jae 0f
  10         ret
  11 0:
  12         movq __libc_errno@GOTTPOFF(%rip), %rcx
  13         neg %eax
  14         movl %eax, %fs:(%rcx)
  15         or $-1, %rax
  16         ret
  17 .size __dup2,.-__dup2
  18 .weak dup2
  19 dup2 = __dup2