[PATCH] dtc: Show the usage text if no parameter is passed

[PATCH] dtc: Show the usage text if no parameter is passed

[Fabio Estevam]

From: Fabio Estevam <fabio.estevam-3arQi8VN3Tc@public.gmane.org>

When dtc is called without any argument the application hangs forever.

Instead of hanging, print the usage and exit.

Signed-off-by: Fabio Estevam <fabio.estevam-3arQi8VN3Tc@public.gmane.org>
---
 dtc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/dtc.c b/dtc.c
index 5ed873c..6308a63 100644
--- a/dtc.c
+++ b/dtc.c
@@ -269,6 +269,8 @@ int main(int argc, char *argv[])
 		}
 	}
 
+	if (argc == 1)
+		usage(NULL);
 	if (argc > (optind+1))
 		usage("missing files");
 	else if (argc < (optind+1))
-- 
2.7.4

Re: [PATCH] dtc: Show the usage text if no parameter is passed

[Rob Herring]

On Wed, Oct 18, 2017 at 6:28 PM, Fabio Estevam <festevam-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> From: Fabio Estevam <fabio.estevam-3arQi8VN3Tc@public.gmane.org>
>
> When dtc is called without any argument the application hangs forever.
>
> Instead of hanging, print the usage and exit.

I think it is valid to do:
dtc < in > out

This doesn't hang:
$ dtc < /dev/null
Error: <stdin>:0.0 syntax error
FATAL ERROR: Unable to parse input tree

The help though isn't clear that input file is optional.

Rob

Re: [PATCH] dtc: Show the usage text if no parameter is passed

[Fabio Estevam]

On Wed, Oct 18, 2017 at 10:02 PM, Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote:
> On Wed, Oct 18, 2017 at 6:28 PM, Fabio Estevam <festevam-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>> From: Fabio Estevam <fabio.estevam-3arQi8VN3Tc@public.gmane.org>
>>
>> When dtc is called without any argument the application hangs forever.
>>
>> Instead of hanging, print the usage and exit.
>
> I think it is valid to do:
> dtc < in > out
>
> This doesn't hang:
> $ dtc < /dev/null
> Error: <stdin>:0.0 syntax error
> FATAL ERROR: Unable to parse input tree

These examples do not have argc == 1.

If 'dtc' is called with no arguments than the application never exits.

Re: [PATCH] dtc: Show the usage text if no parameter is passed

[David Gibson]

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On Wed, Oct 18, 2017 at 10:38:41PM -0200, Fabio Estevam wrote:
> On Wed, Oct 18, 2017 at 10:02 PM, Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote:
> > On Wed, Oct 18, 2017 at 6:28 PM, Fabio Estevam <festevam-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> >> From: Fabio Estevam <fabio.estevam-3arQi8VN3Tc@public.gmane.org>
> >>
> >> When dtc is called without any argument the application hangs forever.
> >>
> >> Instead of hanging, print the usage and exit.
> >
> > I think it is valid to do:
> > dtc < in > out
> >
> > This doesn't hang:
> > $ dtc < /dev/null
> > Error: <stdin>:0.0 syntax error
> > FATAL ERROR: Unable to parse input tree
> 
> These examples do not have argc == 1.

Yes they do.  Everything after the < is processed by the shell and
doesn't appear to dtc as a parameter.

> If 'dtc' is called with no arguments than the application never
> exits.

If dtc is called with no arguments it attempts to read a dts from
standard input and send a dtb to standard output.  It exits when input
finishes.  So, if you press ^D after starting it, it will exit (with
an error, because you haven't put in a valid dts).

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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