Re: [PATCH] passt-repair: Don't use perror(), accept ECONNRESET as termination

On Fri, 7 Feb 2025 13:38:10 +1100
David Gibson <david(a)gibson.dropbear.id.au> wrote:

...
  On Fri, Feb 07, 2025 at 02:29:23AM +0100, Stefano
Brivio wrote:
  On Fri, 7 Feb 2025 12:15:35 +1100
 David Gibson <david(a)gibson.dropbear.id.au> wrote:
   
  On Fri, Feb 07, 2025 at 01:54:39AM +0100, Stefano
Brivio wrote:  
  If we use glibc's perror(), we need to allow
dup() and fcntl() in our
 seccomp profiles, which are a bit too much for this simple helper. On
 top of that, we would probably need a wrapper to avoid allocation for
 translated messages.
 
 While at it: ECONNRESET is just a close() from passt, treat it like
 EOF.
 
 Signed-off-by: Stefano Brivio <sbrivio(a)redhat.com>     
 
 Reviewed-by: David Gibson <david(a)gibson.dropbear.id.au>
   
  ---
  passt-repair.c | 10 +++++++---
  1 file changed, 7 insertions(+), 3 deletions(-)
 
 diff --git a/passt-repair.c b/passt-repair.c
 index 3c3247b..d137a18 100644
 --- a/passt-repair.c
 +++ b/passt-repair.c
 @@ -95,7 +95,7 @@ int main(int argc, char **argv)
  	}
  
  	if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
 -		perror("Failed to create AF_UNIX socket");
 +		fprintf(stderr, "Failed to create AF_UNIX socket:
 %i\n", errno);     
 
 We could use strerror_() here, couldn't we?   
 
 We would need to link that, which is quite some code (the whole 
 strerrordesc_np())... I mean, this runs privileged.   
 
 Hrm, is the non-locale one really that much code though?  Shouldn't it
 be about 5 lines of code and a table of strings?  But then.. glibc is
 really good at making things complicated. 
Right, and the "table of strings" is probably not great to have here.

But the lines of code I was referring to are the weak aliasing trick
(musl doesn't have strerrordesc_np(), which is not POSIX). I could
include util.h, but that means including even more code...

Really, I think numbers fit error messages printed by a privileged
component pretty well.

-- 
Stefano