misc/setfsgid.s

   1 .text
   2  .globl setfsgid
   3  .type setfsgid,@function
   4  .align 1<<4
   5  setfsgid:
   6
   7  movl $123, %eax
   8  syscall
   9  cmpq $-4095, %rax
  10  jae 0f
  11  ret
  12 0: movq __libc_errno@GOTTPOFF(%rip), %rcx
  13  neg %eax
  14  movl %eax, %fs:(%rcx)
  15  or $-1, %rax
  16  ret
  17  .size setfsgid,.-setfsgid