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Re: [Qemu-block] [PATCH v2] qemu-io: Reinitialize optind to 1 (not 0) be
From: |
Eric Blake |
Subject: |
Re: [Qemu-block] [PATCH v2] qemu-io: Reinitialize optind to 1 (not 0) before parsing inner command. |
Date: |
Thu, 3 Jan 2019 13:46:29 -0600 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.1 |
On 1/3/19 3:47 AM, 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.
>
> (From the rest of the man page it is clear that optind must be
> reinitialized to 1).
>
> The glibc man page says:
>
> A program that scans multiple argument vectors, or rescans the same
> vector more than once, and wants to make use of GNU extensions such as
> '+' and '-' at the start of optstring, or changes the value of
> POSIXLY_CORRECT between scans, must reinitialize getopt() by resetting
> optind to 0, rather than the traditional value of 1. (Resetting to 0
> forces the invocation of an internal initialization routine that
> rechecks POSIXLY_CORRECT and checks for GNU extensions in optstring.)
>
> Note I didn't set optreset. It's not present in glibc and the "hard
> reset" is not necessary in this context.
>
> Signed-off-by: Richard W.M. Jones <address@hidden>
> ---
> qemu-io-cmds.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Reviewed-by: Eric Blake <address@hidden>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
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- [Qemu-block] [PATCH v2] qemu-io: Reinitialize optind to 1 (not 0) before parsing inner command., Richard W.M. Jones, 2019/01/03
- [Qemu-block] [PATCH v2] qemu-io: Reinitialize optind to 1 (not 0) before parsing inner command., Richard W.M. Jones, 2019/01/03
- Re: [Qemu-block] [PATCH v2] qemu-io: Reinitialize optind to 1 (not 0) before parsing inner command.,
Eric Blake <=
- Re: [Qemu-block] [PATCH v2] qemu-io: Reinitialize optind to 1 (not 0) before parsing inner command., Max Reitz, 2019/01/07
- Re: [Qemu-block] [PATCH v2] qemu-io: Reinitialize optind to 1 (not 0) before parsing inner command., Eric Blake, 2019/01/07
- Re: [Qemu-block] [PATCH v2] qemu-io: Reinitialize optind to 1 (not 0) before parsing inner command., Max Reitz, 2019/01/07
- Re: [Qemu-block] [PATCH v2] qemu-io: Reinitialize optind to 1 (not 0) before parsing inner command., Eric Blake, 2019/01/07
- Re: [Qemu-block] [PATCH v2] qemu-io: Reinitialize optind to 1 (not 0) before parsing inner command., Max Reitz, 2019/01/07
- Re: [Qemu-block] [PATCH v2] qemu-io: Reinitialize optind to 1 (not 0) before parsing inner command., Eric Blake, 2019/01/07
- Re: [Qemu-block] [PATCH v2] qemu-io: Reinitialize optind to 1 (not 0) before parsing inner command., Max Reitz, 2019/01/09
- Re: [Qemu-block] [PATCH v2] qemu-io: Reinitialize optind to 1 (not 0) before parsing inner command., Richard W.M. Jones, 2019/01/07
- Re: [Qemu-block] [PATCH v2] qemu-io: Reinitialize optind to 1 (not 0) before parsing inner command., Kevin Wolf, 2019/01/08
- Re: [Qemu-block] [PATCH v2] qemu-io: Reinitialize optind to 1 (not 0) before parsing inner command., Eric Blake, 2019/01/08