Re: [Qemu-devel] [PATCH v2] qemu-io: Reinitialize optind to 1 (not 0) before parsing inner command.

[Max Reitz <mreitz@redhat.com>]

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On 03.01.19 10:47, Richard W.M. Jones wrote:
> On FreeBSD 11.2:
> 
>   $ nbdkit memory size=1M --run './qemu-io -f raw -c "aio_write 0 512" $nbd'
>   Parsing error: non-numeric argument, or extraneous/unrecognized suffix -- aio_write
> 
> After main option parsing, we reinitialize optind so we can parse each
> command.  However reinitializing optind to 0 does not work on FreeBSD.
> What happens when you do this is optind remains 0 after the option
> parsing loop, and the result is we try to parse argv[optind] ==
> argv[0] == "aio_write" as if it was the first parameter.
> 
> The FreeBSD manual page says:
> 
>   In order to use getopt() to evaluate multiple sets of arguments, or to
>   evaluate a single set of arguments multiple times, the variable optreset
>   must be set to 1 before the second and each additional set of calls to
>   getopt(), and the variable optind must be reinitialized.

[...]

> Note I didn't set optreset.  It's not present in glibc and the "hard
> reset" is not necessary in this context.

But it sure sounds like FreeBSD requires you to set it, doesn't it?

Max

> Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
> ---
>  qemu-io-cmds.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
> index 2c39124036..aa10ed5a20 100644
> --- a/qemu-io-cmds.c
> +++ b/qemu-io-cmds.c
> @@ -114,7 +114,7 @@ static int command(BlockBackend *blk, const cmdinfo_t *ct, int argc,
>          }
>      }
>  
> -    optind = 0;
> +    optind = 1;
>      return ct->cfunc(blk, argc, argv);
>  }
>  
> 



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