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RE: [PATCH 2/3] tools/hotplug: Fix dhcpd symlink removal in vif-nat

To: Wei Liu <wl@xxxxxxx>, Bertrand Marquis <Bertrand.Marquis@xxxxxxx>

From: Diego Sueiro <Diego.Sueiro@xxxxxxx>

Date: Wed, 9 Sep 2020 12:38:03 +0000

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Cc: "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>, nd <nd@xxxxxxx>, Ian Jackson <ian.jackson@xxxxxxxxxxxxx>

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Thread-topic: [PATCH 2/3] tools/hotplug: Fix dhcpd symlink removal in vif-nat

>-----Original Message----- >From: Wei Liu <wl@xxxxxxx> >Sent: 07 September 2020 16:10 >To: Bertrand Marquis <Bertrand.Marquis@xxxxxxx> >Cc: Wei Liu <wl@xxxxxxx>; Diego Sueiro <Diego.Sueiro@xxxxxxx>; xen- >devel@xxxxxxxxxxxxxxxxxxxx; nd <nd@xxxxxxx>; Ian Jackson ><ian.jackson@xxxxxxxxxxxxx> >Subject: Re: [PATCH 2/3] tools/hotplug: Fix dhcpd symlink removal in vif-nat > >On Mon, Sep 07, 2020 at 03:01:37PM +0000, Bertrand Marquis wrote: >> Hi Wei, >> >> > On 7 Sep 2020, at 15:36, Wei Liu <wl@xxxxxxx> wrote: >> > >> > On Thu, Aug 20, 2020 at 12:00:23PM +0100, Diego Sueiro wrote: >> >> Copy temp files used to add/remove dhcpd configurations to avoid >> >> replacing potential symlinks. >> >> >> > >> > Can you clarify the issue you saw a bit? >> > >> > Which one of the parameter is a symlink (I assume the latter) and >> > what problem you see with replacing the symlinks? >> >> Maybe i can explain here. >> >> If you have this: >> /etc/dhcp.conf -> dhcp.conf.real >> >> mv will create a new file dhcp.conf where cp will actually modify >> dhcp.conf.real instead of replacing the symlink with a real file. >> >> This prevents some mistakes where the user will actually continue to >> modify dhcp.conf.real where it would not be the one used anymore. > >OK. Now I understand the use case. Thanks. > >I think you explanation should be part of the commit message. > >Diego, can you please incorporate Bertrand's explanation and deal with my >comment below? > Done and v2 sent to the mailing list. Thanks for your review. -- Diego Sueiro >> >> --- >> >> tools/hotplug/Linux/vif-nat | 12 +++++++----- >> >> 1 file changed, 7 insertions(+), 5 deletions(-) >> >> >> >> diff --git a/tools/hotplug/Linux/vif-nat >> >> b/tools/hotplug/Linux/vif-nat index 2614435..1ab80ed 100644 >> >> --- a/tools/hotplug/Linux/vif-nat >> >> +++ b/tools/hotplug/Linux/vif-nat >> >> @@ -99,7 +99,8 @@ dhcparg_remove_entry() >> >> then >> >> rm "$tmpfile" >> >> else >> >> - mv "$tmpfile" "$dhcpd_arg_file" >> >> + cp "$tmpfile" "$dhcpd_arg_file" >> >> + rm "$tmpfile" >> >> fi >> > >> > You could've simplified the code a bit here and below now that both >> > branches issue the same rm command. > >Wei.

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