Re: [PULL 02/15] linux-user: Move syscall error detection into safe_syscall_base

[Laurent Vivier]

Le 20/12/2021 à 21:24, Richard Henderson a écrit :
> The current api from safe_syscall_base() is to return -errno, which is
> the interface provided by *some* linux kernel abis.  The wrapper macro,
> safe_syscall(), detects error, stores into errno, and returns -1, to
> match the api of the system syscall().
>
> For those kernel abis that do not return -errno natively, this leads
> to double syscall error detection.  E.g. Linux ppc64, which sets the
> SO flag for error.
>
> Simplify the usage from C by moving the error detection into assembly,
> and usage from assembly by providing a C helper with which to set errno.
>
> Reviewed-by: Warner Losh <imp@bsdimp.com>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   linux-user/safe-syscall.h                  | 16 +++-------
>   linux-user/safe-syscall-error.c            | 28 ++++++++++++++++
>   linux-user/host/aarch64/safe-syscall.inc.S | 20 ++++++------
>   linux-user/host/arm/safe-syscall.inc.S     | 27 ++++++++++------
>   linux-user/host/i386/safe-syscall.inc.S    | 37 +++++++++++++++-------
>   linux-user/host/ppc64/safe-syscall.inc.S   | 24 +++++++-------
>   linux-user/host/riscv/safe-syscall.inc.S   | 20 ++++++------
>   linux-user/host/s390x/safe-syscall.inc.S   | 32 ++++++++++++-------
>   linux-user/host/x86_64/safe-syscall.inc.S  | 29 +++++++++--------
>   linux-user/meson.build                     |  1 +
>   10 files changed, 147 insertions(+), 87 deletions(-)
>   create mode 100644 linux-user/safe-syscall-error.c

This patch breaks command execution in bash command line interface:

- if I run "chroot chroot/powerpc/jessie ls", it works

- if I run "echo ls |  chroot chroot/powerpc/jessie", it hangs

- if I run "chroot chroot/powerpc/jessie bash invalid_command",
  it does nothing whereas it should return "bash: invalid_command: No such file or 
directory".

I think the exit status of the command is not correctly detected by bash.

Thanks,
Laurent