Re: kern/52342: linux ABI exit(non-zero) returns zero status to the parent process

[u-bc8k%aetey.se@localhost]

Thanks for paying attention.

On Mon, Jun 26, 2017 at 11:40:01AM +0000, matthew green wrote:
>  space-bird ~> file /emul/linux/usr/bin/false /emul/linux32/usr/bin/false
>  /emul/linux/usr/bin/false:   ELF 64-bit LSB executable, x86-64, version 1 =
>  (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.32, Build=
>  ID[sha1]=3D87be6d24cdaaa0afd60da1ad48c016f5ea709410, stripped
>  /emul/linux32/usr/bin/false: ELF 32-bit LSB executable, Intel 80386, versi=
>  on 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.16, =
>  BuildID[sha1]=3D9d82388dd6116aa6920afeba401ac10b80906fff, stripped
>  space-bird ~> /emul/linux/usr/bin/false || echo good
>  good
>  space-bird ~> /emul/linux32/usr/bin/false || echo good
>  good
>  
>  can you ktrace your binaries and see what happens?

Sure:

-----------------------
$ file cat
cat: ELF 32-bit LSB executable, Intel 80386, version 1 (GNU/Linux), statically linked, stripped
$ ./cat /nosuchfile && echo BAD
cat: /nosuchfile: No such file or directory
BAD
$ ktrace ./cat /nosuchfile
cat: /nosuchfile: No such file or directory
$ kdump
  9256      1 ktrace   EMUL  "netbsd"
  9256      1 ktrace   CALL  execve(0x7f7ffffffe7f,0x7f7fffffdcc0,0x7f7fffffdcd8)
  9256      1 ktrace   NAMI  "./cat"
  9256      1 cat      NAMI  "/emul/linux32"
  9256   9256 cat      EMUL  "linux32"
  9256   9256 cat      RET   execve -1 errno -2 No such file or directory
  9256   9256 cat      CALL  open(0xbffffe56,0,0)
  9256   9256 cat      NAMI  "/nosuchfile"
  9256   9256 cat      RET   open -1 errno -2 No such file or directory
  9256   9256 cat      CALL  netbsd32_write(2,0x80485bc,5)
  9256   9256 cat      GIO   fd 2 wrote 5 bytes
       "cat: "
  9256   9256 cat      RET   netbsd32_write 5
  9256   9256 cat      CALL  netbsd32_write(2,0xbffffe56,0xb)
  9256   9256 cat      GIO   fd 2 wrote 11 bytes
       "/nosuchfile"
  9256   9256 cat      RET   netbsd32_write 11/0xb
  9256   9256 cat      CALL  netbsd32_write(2,0x80485b8,2)
  9256   9256 cat      GIO   fd 2 wrote 2 bytes
       ": "
  9256   9256 cat      RET   netbsd32_write 2
  9256   9256 cat      CALL  netbsd32_write(2,0x8048898,0x19)
  9256   9256 cat      GIO   fd 2 wrote 25 bytes
       "No such file or directory"
  9256   9256 cat      RET   netbsd32_write 25/0x19
  9256   9256 cat      CALL  netbsd32_write(2,0x80485b4,1)
  9256   9256 cat      GIO   fd 2 wrote 1 bytes
       "\n"
  9256   9256 cat      RET   netbsd32_write 1
  9256   9256 cat      CALL  exit(1)
$ uname -a
NetBSD XXXX 7.1 NetBSD 7.1 (GENERIC.201703111743Z) amd64
-----------------------

My guess is that your test binaries do not use exit() but rather
exit_group(). The use of old-style syscalls apparently is rare
nowadays but as long as exit() is supported it would be nice if it
behaves.