Fix compiler warning in linux-namespaces.c

  ../../gdb/nat/linux-namespaces.c: In function ‘void mnsh_main(int)’:
../../gdb/nat/linux-namespaces.c:604:8: warning: ‘fd’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  close (fd);
  ~~~~~~^~~~

And the warning is correct -- mnsh_recv_message can return -1 and leave fd
uninitialized, and mnsh_main will still call close (fd) if that happens.

Initialize fd to -1 to avoid that.

gdb/ChangeLog:

2019-08-27  Christian Biesinger  <cbiesinger@google.com>

	* nat/linux-namespaces.c (mnsh_main): Initialize fd (to -1).
---
 gdb/nat/linux-namespaces.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
  

On Tuesday, August 27 2019, Christian Biesinger via gdb-patches wrote:

> ../../gdb/nat/linux-namespaces.c: In function ‘void mnsh_main(int)’:
> ../../gdb/nat/linux-namespaces.c:604:8: warning: ‘fd’ may be used uninitialized in this function [-Wmaybe-uninitialized]
>   close (fd);
>   ~~~~~~^~~~
>
> And the warning is correct -- mnsh_recv_message can return -1 and leave fd
> uninitialized, and mnsh_main will still call close (fd) if that happens.
>
> Initialize fd to -1 to avoid that.

Thanks.  IMO this patch could be treated as obvious.

> gdb/ChangeLog:
>
> 2019-08-27  Christian Biesinger  <cbiesinger@google.com>
>
> 	* nat/linux-namespaces.c (mnsh_main): Initialize fd (to -1).
> ---
>  gdb/nat/linux-namespaces.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/gdb/nat/linux-namespaces.c b/gdb/nat/linux-namespaces.c
> index 503f755903..57843cda36 100644
> --- a/gdb/nat/linux-namespaces.c
> +++ b/gdb/nat/linux-namespaces.c
> @@ -562,14 +562,14 @@ mnsh_main (int sock)
>    while (1)
>      {
>        enum mnsh_msg_type type;
> -      int fd, int1, int2;
> +      int fd = -1, int1, int2;
>        char buf[PATH_MAX];
>        ssize_t size, response = -1;
>  
>        size = mnsh_recv_message (sock, &type,
>  				&fd, &int1, &int2,
>  				buf, sizeof (buf));
> -
> +`

This seems like a typo.

>        if (size >= 0 && size < sizeof (buf))
>  	{
>  	  switch (type)
> -- 
> 2.23.0.187.g17f5b7556c-goog

Cheers,
  

On Tue, Aug 27, 2019 at 1:42 PM Sergio Durigan Junior
<sergiodj@redhat.com> wrote:
>
> On Tuesday, August 27 2019, Christian Biesinger via gdb-patches wrote:
>
> > ../../gdb/nat/linux-namespaces.c: In function ‘void mnsh_main(int)’:
> > ../../gdb/nat/linux-namespaces.c:604:8: warning: ‘fd’ may be used uninitialized in this function [-Wmaybe-uninitialized]
> >   close (fd);
> >   ~~~~~~^~~~
> >
> > And the warning is correct -- mnsh_recv_message can return -1 and leave fd
> > uninitialized, and mnsh_main will still call close (fd) if that happens.
> >
> > Initialize fd to -1 to avoid that.
>
> Thanks.  IMO this patch could be treated as obvious.

Thanks, fixed the typo below and pushed as obvious.

> > gdb/ChangeLog:
> >
> > 2019-08-27  Christian Biesinger  <cbiesinger@google.com>
> >
> >       * nat/linux-namespaces.c (mnsh_main): Initialize fd (to -1).
> > ---
> >  gdb/nat/linux-namespaces.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/gdb/nat/linux-namespaces.c b/gdb/nat/linux-namespaces.c
> > index 503f755903..57843cda36 100644
> > --- a/gdb/nat/linux-namespaces.c
> > +++ b/gdb/nat/linux-namespaces.c
> > @@ -562,14 +562,14 @@ mnsh_main (int sock)
> >    while (1)
> >      {
> >        enum mnsh_msg_type type;
> > -      int fd, int1, int2;
> > +      int fd = -1, int1, int2;
> >        char buf[PATH_MAX];
> >        ssize_t size, response = -1;
> >
> >        size = mnsh_recv_message (sock, &type,
> >                               &fd, &int1, &int2,
> >                               buf, sizeof (buf));
> > -
> > +`
>
> This seems like a typo.
>
> >        if (size >= 0 && size < sizeof (buf))
> >       {
> >         switch (type)
> > --
> > 2.23.0.187.g17f5b7556c-goog
>
> Cheers,
>
> --
> Sergio
> GPG key ID: 237A 54B1 0287 28BF 00EF  31F4 D0EB 7628 65FC 5E36
> Please send encrypted e-mail if possible
> http://sergiodj.net/