Hi OpenSSH users,
I am using openSSH (now 2.9.9p2, but prob occurs in 2.9p2 also) to execute commands on a remote machine which outputs data to stdout then pipes it to another invocation of ssh which connects back to the first machine in the same way, where it starts a program to read and store the output from the command on the second machine. I am using the "command" option in the keys file to force execution of a particular command when that key is used for authentication. My problem is this. The remote ssh returns an error code of 255 (using echo $?), or (-1 in the debug), despite the command executing successfully. about 5-10% of the time it returns 0. In all cases it "appears" the command completed successully, and is simply an issue of ssh failing to close the channel cleanly. My guess is that one side is closing before the other acknowledges and therefore thinks the channel has been prematurely terminated. My questions are: How sure can I be that I am indeed getting all data from the pipe? How can I accurately determine the exit status of the command (ufsdump) which is piping data into ssh, regardless of ssh's exit status ? Has anyone else seen this problem and/or resolved it ? If more debug would be helpful, please let me know... Below is the debug from the remote side when it fails: <snip> debug1: Remote: Forced command: /les/galaxy/sysadmin/backup/sbin/receiver debug1: input_userauth_pk_ok: pkalg ssh-dss blen 435 lastkey 12bac0 hint 0 debug1: read PEM private key done: type DSA debug1: sig size 20 20 debug1: Remote: Forced command: /les/galaxy/sysadmin/backup/sbin/receiver debug1: ssh-userauth2 successful: method publickey debug1: fd 5 setting O_NONBLOCK debug1: fd 7 setting O_NONBLOCK debug1: fd 8 setting O_NONBLOCK debug1: channel 0: new [client-session] debug1: channel_new: 0 debug1: send channel open 0 debug1: Entering interactive session. debug1: client_init id 0 arg 0 debug1: channel request 0: shell debug1: channel 0: open confirm rwindow 0 rmax 16384 debug1: channel 0: read<=0 rfd 5 len 0 debug1: channel 0: read failed debug1: channel 0: input open -> drain debug1: channel 0: close_read debug1: channel 0: input: no drain shortcut debug1: channel 0: ibuf empty debug1: channel 0: input drain -> closed debug1: channel 0: send eof debug1: channel 0: rcvd eof debug1: channel 0: output open -> drain debug1: channel 0: rcvd close debug1: channel 0: obuf empty debug1: channel 0: output drain -> closed debug1: channel 0: close_write debug1: channel 0: send close debug1: channel 0: is dead debug1: channel_free: channel 0: status: The following connections are open: #0 client-session (t4 r0 i8/0 o128/0 fd -1/-1) debug1: channel_free: channel 0: dettaching channel user debug1: Transferred: stdin 0, stdout 0, stderr 0 bytes in 15.3 seconds debug1: Bytes per second: stdin 0.0, stdout 0.0, stderr 0.0 debug1: Exit status -1 This is the debug when it works: OpenSSH_2.9p2, SSH protocols 1.5/2.0, OpenSSL 0x0090602f debug1: Reading configuration data /opt/OBSDssh/etc/ssh_config debug1: Seeding random number generator debug1: Rhosts Authentication disabled, originating port will not be trusted. debug1: restore_uid debug1: ssh_connect: getuid 0 geteuid 0 anon 1 debug1: Connecting to galaxy [my_ip_was_here] port 22. debug1: temporarily_use_uid: 0/1 (e=0) debug1: restore_uid debug1: temporarily_use_uid: 0/1 (e=0) debug1: restore_uid debug1: Connection established. debug1: read PEM private key done: type DSA debug1: read PEM private key done: type RSA debug1: identity file /.ssh/backup-sender type 2 debug1: Remote protocol version 2.0, remote software version OpenSSH_2.9p2 debug1: match: OpenSSH_2.9p2 pat ^OpenSSH Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_2.9p2 debug1: SSH2_MSG_KEXINIT sent debug1: SSH2_MSG_KEXINIT received debug1: kex: server->client aes128-cbc hmac-md5 none debug1: kex: client->server aes128-cbc hmac-md5 none debug1: SSH2_MSG_KEX_DH_GEX_REQUEST sent debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP debug1: dh_gen_key: priv key bits set: 135/256 debug1: bits set: 1017/2049 debug1: SSH2_MSG_KEX_DH_GEX_INIT sent debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY debug1: Host 'galaxy' is known and matches the RSA host key. debug1: Found key in //.ssh/known_hosts2:1 debug1: bits set: 1027/2049 debug1: ssh_rsa_verify: signature correct debug1: kex_derive_keys debug1: newkeys: mode 1 debug1: SSH2_MSG_NEWKEYS sent debug1: waiting for SSH2_MSG_NEWKEYS debug1: newkeys: mode 0 debug1: SSH2_MSG_NEWKEYS received debug1: done: ssh_kex2. debug1: send SSH2_MSG_SERVICE_REQUEST debug1: service_accept: ssh-userauth debug1: got SSH2_MSG_SERVICE_ACCEPT debug1: authentications that can continue: publickey,password,keyboard-interactive debug1: next auth method to try is publickey debug1: try pubkey: /.ssh/backup-sender debug1: Remote: Forced command: /les/galaxy/sysadmin/backup/sbin/receiver debug1: input_userauth_pk_ok: pkalg ssh-dss blen 435 lastkey 12bac0 hint 0 debug1: read PEM private key done: type DSA debug1: sig size 20 20 debug1: Remote: Forced command: /les/galaxy/sysadmin/backup/sbin/receiver debug1: ssh-userauth2 successful: method publickey debug1: fd 5 setting O_NONBLOCK debug1: fd 7 setting O_NONBLOCK debug1: fd 8 setting O_NONBLOCK debug1: channel 0: new [client-session] debug1: channel_new: 0 debug1: send channel open 0 debug1: Entering interactive session. debug1: client_init id 0 arg 0 debug1: channel request 0: shell debug1: channel 0: open confirm rwindow 0 rmax 16384 debug1: channel 0: read<=0 rfd 5 len 0 debug1: channel 0: read failed debug1: channel 0: input open -> drain debug1: channel 0: close_read debug1: channel 0: input: no drain shortcut debug1: channel 0: ibuf empty debug1: channel 0: input drain -> closed debug1: channel 0: send eof debug1: client_input_channel_req: channel 0 rtype exit-status reply 0 debug1: channel 0: rcvd eof debug1: channel 0: output open -> drain debug1: channel 0: rcvd close debug1: channel 0: obuf empty debug1: channel 0: output drain -> closed debug1: channel 0: close_write debug1: channel 0: send close debug1: channel 0: is dead debug1: channel_free: channel 0: status: The following connections are open: #0 client-session (t4 r0 i8/0 o128/0 fd -1/-1) debug1: channel_free: channel 0: dettaching channel user debug1: Transferred: stdin 0, stdout 0, stderr 0 bytes in 16.3 seconds debug1: Bytes per second: stdin 0.0, stdout 0.0, stderr 0.0 debug1: Exit status 0 Thanks, Dave -- --------------------------------------------------------------- David Batterham PHONE: +61 3 95001017 System Administrator FAX: +61 3 95001191 Lochard Pty Ltd EMAIL: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
