CODEWITHSUNDEEP
ftplftp
Sean Phelan
Sean Phelan

Reputation: 36

lftp handling of negative response to ALLO

I'm using lftp 4.8.4 on Ubuntu 20.4 with my own ftpd server code.

As the debug log below shows, in preparation for a transfer lftp sends ALLO but appears to ignore the negative response (452 "no space").

I've also tried a 552 "Exceeded storage allocation" response, which was also ignored.

Is there a more appropriate response? Am I misunderstanding the role of ALLO?

Any and all suggestions welcome! Thanks.

    > put lfs.img -o lfs3
    ---- Connecting to ftpd (192.168.0.171) port 21
    <--- 220 nil                         
    ---> FEAT
    <--- 211-Extensions supported:             
    <---  SIZE
    <---  REST STREAM
    <---  PASV
    <--- 211 END
    ---> USER anonymous
    <--- 331 nil                         
    ---> PASS lftp@
    <--- 230 nil                               
    ---> PWD
    <--- 257 /                                     
    ---> TYPE I
    <--- 200 nil                                   
    ---> PASV
    <--- 227 Entering Passive Mode. 192,168,0,171,255,249
    ---- Connecting data socket to (192.168.0.171) port 65529
    ---- Data connection established
    ---> ALLO 72408
    <--- 452 no space                              
    ---> STOR lfs3
    <--- 500 open fail                             
    ---- Closing data socket
    put: lfs.img: Fatal error: 500 open fail

Upvotes: 0

Views: 243

Answers (1)

Sean Phelan
Sean Phelan

Reputation: 36

lftp correctly handles a response of 552 ("Requested file action aborted. Exceeded storage allocation") to an ALLO command. lftp responds to the 552 response with a STOR command, immediately followed by an ABOR (ie. Abort) command.

From RFC 959 (para 4.1.3.): "This command [ALLO] shall be followed by a STORe or APPEnd command." So although the STOR command will not succeed, it would be incorrect to skip it and just send ABOR.

Upvotes: 1

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