Re: bin/58281: ftp(1) should have a strict failure exit code option

[Luke Mewburn <luke%mewburn.net@localhost>]

The following reply was made to PR bin/58281; it has been noted by GNATS.

From: Luke Mewburn <luke%mewburn.net@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost
Subject: Re: bin/58281: ftp(1) should have a strict failure exit code option
Date: Fri, 19 Jul 2024 12:39:02 +1000

 On 24-05-25 12:10, martin%NetBSD.org@localhost wrote:
   | >Number:         58281
   | >Category:       bin
   | >Synopsis:       ftp(1) should have a strict failure exit code option
   | >Description:
   | 
   | It is possible to use ftp(1) in scripts to auto-download e.g. software
   | updates. But if the connection fails midway (due to network issues)
   | a sucess error code is returned to the shell. This makes auto-update
   | scripts prone to silent failure.
 
 That's a sensible request.
 
 If the file size is known, and the transferred bytes is short (taking
 into account any restart point), then that could be considered a fetch
 failure.
 
 
   | Example:
   | 
   | Requesting https://.....
   |   4% |*                                  |  6779 KiB    9.78 KiB/s  4:30:23 ETA
   | 6941845 bytes retrieved in 11:32 (9.78 KiB/s)
   | 
   | and exit status is zero. As you can see from the transfer rate the connection
   | was ... challenged, and something timed out and droped the whole connection
   | midway. The client does not report this in any way that I can find, and
   | the announced size of the file is not easily available to the script
   | unless the whole application transfers a manifest first.
   | 
   | >Fix:
   | Add a command line option to force the exit status to indicate failure
   | if less than the original announced number of bytes have been received?
 
 I think that failing could be the default behaviour, instead of adding a
 new option.
 
 If you can (relatively) easily reproduce the issue, can you test if this
 patch does what you want?
 
 I've only fixed it for fetch_url(), because I /think/ that fetch_ftp
 should already detect the error.
 
 
 diff --git i/usr.bin/ftp/fetch.c w/usr.bin/ftp/fetch.c
 index a2ccd8c3897a..83c9ec15df08 100644
 --- i/usr.bin/ftp/fetch.c
 +++ w/usr.bin/ftp/fetch.c
 @@ -1856,6 +1856,11 @@ chunkerror:
  	}
  	if (bytes > 0)
  		ptransfer(0);
 +
 +		/* fail if short transfer when filesize is known */
 +	if (filesize >= 0 && (bytes + restart_point < filesize))
 +		goto cleanup_fetch_url;
 +
  	bytes = 0;
  
  	rval = 0;