Subject: Re: [PATCH iproute2-next 1/8] iplink: Return from function instead of calling exit()

From: Stephen Hemminger <[email-masked]>
Date: Tue, 20 Feb 2018 12:33:15 -0800

On Tue, 20 Feb 2018 13:27:21 -0700
David Ahern <[email-masked]> wrote:

> On 2/20/18 1:17 PM, Serhey Popovych wrote:
> > Stephen Hemminger wrote:  
> >> On Tue, 20 Feb 2018 21:39:51 +0200
> >> Serhey Popovych <[email-masked]> wrote:
> >>  
> >>> Signed-off-by: Serhey Popovych <[email-masked]>
> >>> ---
> >>>  ip/iplink.c |   12 ++++++------
> >>>  1 file changed, 6 insertions(+), 6 deletions(-)
> >>>
> >>> diff --git a/ip/iplink.c b/ip/iplink.c
> >>> index 74c377c..a2c8108 100644
> >>> --- a/ip/iplink.c
> >>> +++ b/ip/iplink.c
> >>> @@ -653,7 +653,7 @@ int iplink_parse(int argc, char **argv, struct iplink_req *req,
> >>>  			NEXT_ARG();
> >>>  			if (xdp_parse(&argc, &argv, req, dev_index,
> >>>  				      generic, drv, offload))
> >>> -				exit(-1);
> >>> +				return -1;
> >>>  		} else if (strcmp(*argv, "netns") == 0) {
> >>>  			NEXT_ARG();
> >>>  			if (netns != -1)
> >>> @@ -972,12 +972,12 @@ static int iplink_modify(int cmd, unsigned int flags, int argc, char **argv)
> >>>  		if (!dev) {
> >>>  			fprintf(stderr,
> >>>  				"Not enough information: \"dev\" argument is required.\n");
> >>> -			exit(-1);
> >>> +			return -1;
> >>>  		}
> >>>  		if (cmd == RTM_NEWLINK && index) {
> >>>  			fprintf(stderr,
> >>>  				"index can be used only when creating devices.\n");
> >>> -			exit(-1);
> >>> +			return -1;
> >>>  		}
> >>>  
> >>>  		req.i.ifi_index = ll_name_to_index(dev);
> >>> @@ -1392,7 +1392,7 @@ static int do_set(int argc, char **argv)
> >>>  	if (!dev) {
> >>>  		fprintf(stderr,
> >>>  			"Not enough of information: \"dev\" argument is required.\n");
> >>> -		exit(-1);
> >>> +		return -1;
> >>>  	}
> >>>  
> >>>  	if (newaddr || newbrd) {
> >>> @@ -1553,7 +1553,7 @@ static int iplink_afstats(int argc, char **argv)
> >>>  			fprintf(stderr,
> >>>  				"Command \"%s\" is unknown, try \"ip link help\".\n",
> >>>  				*argv);
> >>> -			exit(-1);
> >>> +			return -1;
> >>>  		}
> >>>  
> >>>  		argv++; argc--;
> >>> @@ -1648,5 +1648,5 @@ int do_iplink(int argc, char **argv)
> >>>  
> >>>  	fprintf(stderr, "Command \"%s\" is unknown, try \"ip link help\".\n",
> >>>  		*argv);
> >>> -	exit(-1);
> >>> +	return -1;
> >>>  }  
> >>
> >> Not sure I like this. If given bad input in batch it is better to stop and exit
> >> rather than continuing with more bad data.  
> > 
> > When preparing this change I think in opposite direction: we want to
> > continue batch mode if single line is broken.
> >   
> 
> batch mode needs to stop on the line that fails. That said, batch still
> fails with the /exit/return/ change
> 
> $ cat /tmp/ip.batch
> li sh
> li foo
> li add veth1 type veth peer name veth2
> 
> Current command
> $ ip -batch /tmp/ip.batch
> 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode
> DEFAULT group default qlen 1000
>     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
> 
> <link list snipped>
> Command "foo" is unknown, try "ip link help".
> $ echo $?
> 255
> 
> $ ip/ip -batch /tmp/ip.batch
> 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode
> DEFAULT group default qlen 1000
>     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
> <link list snipped>
> Command "foo" is unknown, try "ip link help".
> Command failed /tmp/ip.batch:2
> dsa@kenny:~/iproute2/iproute2-next.git$ echo $?
> 1
> 
> I like that better because it tells me the line that fails.

Normally ip batch will exit on errors.
The question is what about -force?