fgets and ssh

fgets and ssh

[Benoît Rouits]

hello,
in a minimal shell tutorial written in C, i have a read_line function
that does:

char* read_line()
{
    char* line=NULL;
    line=(char*)malloc(512);
    line=fgets(line,512,stdin);
    return line;
}

then i parse this line to build a correct "argv" to pass to execvp()
everything works well when i use ssh interactively.

The problem i encounter is when i pass a command to ssh into this shell:

ssh -v guest@localhost ls
[...]
guest@localhost's password:
debug1: Authentication succeeded (password).
debug1: channel 0: new [client-session]
debug1: Entering interactive session.
debug1: Sending environment.
debug1: Sending env LANG = fr_FR.utf8
debug1: Sending command: ls
( here the shell waits )

the shell still waits for ls and i have to retype intaractively "ls" to
get the correct result:

ls
debug1: client_input_channel_req: channel 0 rtype exit-status reply 0
Desktop
Examples
debug1: channel 0: free: client-session, nchannels 1
debug1: Transferred: stdin 0, stdout 0, stderr 0 bytes in 61.4 seconds
debug1: Bytes per second: stdin 0.0, stdout 0.0, stderr 0.0
debug1: Exit status 9

any explanation would be greatly appreciated.

+ben

Re: fgets and ssh

[Stephen Kratzer]

On Wednesday 11 April 2007 08:17, Benoît Rouits wrote:
> hello,
> in a minimal shell tutorial written in C, i have a read_line function
> that does:
>
> char* read_line()
> {
>     char* line=NULL;
>     line=(char*)malloc(512);
>     line=fgets(line,512,stdin);
>     return line;
> }
>
> then i parse this line to build a correct "argv" to pass to execvp()
> everything works well when i use ssh interactively.
>
> The problem i encounter is when i pass a command to ssh into this shell:
>
> ssh -v guest@localhost ls
> [...]
> guest@localhost's password:
> debug1: Authentication succeeded (password).
> debug1: channel 0: new [client-session]
> debug1: Entering interactive session.
> debug1: Sending environment.
> debug1: Sending env LANG = fr_FR.utf8
> debug1: Sending command: ls
> ( here the shell waits )
>
> the shell still waits for ls and i have to retype intaractively "ls" to
> get the correct result:
>
> ls
> debug1: client_input_channel_req: channel 0 rtype exit-status reply 0
> Desktop
> Examples
> debug1: channel 0: free: client-session, nchannels 1
> debug1: Transferred: stdin 0, stdout 0, stderr 0 bytes in 61.4 seconds
> debug1: Bytes per second: stdin 0.0, stdout 0.0, stderr 0.0
> debug1: Exit status 9
>
> any explanation would be greatly appreciated.
>
> +ben
> -
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When ssh is executed in the form 'ssh user@host command', the login shell of 
the user will be called like so: 'shell -c command'. That is, commands are 
not fed into the shell interactively on stdin, they're provided as arguments 
following a -c option flag.
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Re: fgets and ssh [resolved]

[Benoît Rouits]

Thank you very much Stephen, now it works with "-c command"
and so "scp" can also work.

Le mercredi 11 avril 2007 à 10:01 -0400, Stephen Kratzer a écrit :
> When ssh is executed in the form 'ssh user@host command', the login
> shell of 
> the user will be called like so: 'shell -c command'. That is, commands
> are 
> not fed into the shell interactively on stdin, they're provided as
> arguments 
> following a -c option flag. 
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