Re: [golang-dev] os.File.Seek() function panics on a pipe

[Dave Cheney]

Thank you for your detailed bug report, but you forgot the most
important thing, the panic message.

On Mon, Oct 8, 2012 at 10:14 AM, <gvds...@gmail.com> wrote:
> Hello, when I am using the Seek function on a pipe, it panics. Shouldn't it
> just generate an error? It also crashes in the sandbox when running
> "pipe.go"
>
> The code is: hello.go and pipe.go
>
> Building with "go build hello.go" and "go build pipe.go"
> To execute type: ./hello | ./pipe
>
> Debian 6.0 32 bit. Go 1.0.3
>
> Gerard

[Brad Fitzpatrick]

It's the Stat call that's crashing the sandox, not Seek:

http://play.golang.org/p/iPi2W77KxD

[Brad Fitzpatrick]

Uh, I didn't even notice you were calling Size.  If you remove the method call, you can see the real error without crashing:

http://play.golang.org/p/3tKUjEqdla

[minux]

On Mon, Oct 8, 2012 at 11:15 AM, Gerard <gvds...@gmail.com> wrote:

Ok, I narrowed it down a bit:

Running this code from the sandbox, you get the message: 

seek = 0, err = permission denied

Seems the sandbox is pretty strict, and only allows read and write to existing

file descriptors. 

Running the same code as a standalone program the output is: 

seek = 0, err = %v(PANIC=runtime error: invalid memory address or nil pointer dereference)

I can't reproduce this.

On OS X/FreeBSD/Linux the output is:

seek = 0, err = seek /dev/stdin: illegal seek

What OS do you use?

[Gerard]

Running the same code as a standalone program the output is: 

seek = 0, err = %v(PANIC=runtime error: invalid memory address or nil pointer dereference)

I can't reproduce this.

On OS X/FreeBSD/Linux the output is:

seek = 0, err = seek /dev/stdin: illegal seek

What OS do you use?

 Linux 32 bit Debian 6 (with vmware player)