| Summary: | Running nohup sleep 70 & and then exiting shell, hangs ssh | ||||||||
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| Product: | Portable OpenSSH | Reporter: | Jeff White <jwhite> | ||||||
| Component: | sshd | Assignee: | Assigned to nobody <unassigned-bugs> | ||||||
| Status: | CLOSED FIXED | ||||||||
| Severity: | normal | CC: | djm, dtucker, jwhite | ||||||
| Priority: | P2 | ||||||||
| Version: | 5.0p1 | ||||||||
| Hardware: | SPARC | ||||||||
| OS: | Solaris | ||||||||
| Bug Depends on: | |||||||||
| Bug Blocks: | 1452 | ||||||||
| Attachments: |
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Description
Jeff White
2008-05-13 06:27:00 AEST
This is holding us up moving to SSH exclusively. Telnet does not do this when someone nohups a process and throws it into the background. The shell warns you once and then allows you to exit if you type exit on the shell again. You are immediately returned to your host and the process is still running. I do thank you for your time looking into this. Have a good day. What vendor/version SSH server are you connecting to? If it is OpenSSH, could you please attach a debug trace from the server (/path/to/sshd -ddd) Created attachment 1501 [details]
Debug that Damien requested
Version of sshd is: OpenSSH_5.0p1, OpenSSL 0.9.8g 19 Oct 2007 compiled for and running on Solaris 10 x86. Solaris 10 version is Solaris 10 x86 (5/08). Thank you again. Client I am connecting from is OpenSSH_5.0p1, OpenSSL 0.9.8g 19 Oct 2007 compiled for and running on Solaris 10 SPARC. I can reproduce this on Solaris 10/x86. trussing sshd shows this: 20238: close(10) = 0 20238: waitid(P_ALL, 0, 0x080478F0, WEXITED|WTRAPPED|WNOHANG) Err#10 ECHILD 20238: lwp_sigmask(SIG_SETMASK, 0x00000000, 0x00000000) = 0xFFBFFEFF [0x0000FFFF] 20238: pollsys(0x080478D0, 3, 0x00000000, 0x00000000) = 2 20238: read(4, "\0", 1) = 1 20238: read(4, 0x08047983, 1) Err#11 EAGAIN 20238: lwp_sigmask(SIG_SETMASK, 0x00020000, 0x00000000) = 0xFFBFFEFF [0x0000FFFF] 20238: lwp_sigmask(SIG_SETMASK, 0x00000000, 0x00000000) = 0xFFBFFEFF [0x0000FFFF] 20238: write(5, " 6 wCAC0FD89 ,8DBE |96 %".., 48) = 48 20234: read(6, 0x080475A8, 4) (sleeping...) 20238: pollsys(0x080478D0, 3, 0x00000000, 0x00000000) (sleeping...) Descriptor 5 is the socket connected to the client, 4 and 6 are pipes, presumably connected to the shell. Created attachment 1528 [details]
Do not rely on isatty(ptymaster)
Please try this patch against 5.0p1.
Damien figured it out. sshd relies on isatty() to determine whether or not a given channel is connected to a pty, however this doesn't work on Solaris for a pty master (which is entirely reasonable, since it's not a tty). This flag, in turn, controls whether or not the infamous hang-on-exit fixes are used.
This diff adds an extra parameter that controls whether or not a given channel is connected to a pty, rather than relying on undefined semantics.
A similar patch has been applied and will be in OpenSSH 5.1. Thanks for the report. Thanks for the update, guys. I appreciate your help. I will get these patches added when I can. I hope to have something by the end of this week, but I'm not sure. Anyway, I'll try your fix out and report back. This patch does work. It solves my problem. Thank you for your time. I need to test it on a SPARC install of Solaris 10, but the sshd I just compiled for Solaris 10 x86 works fine. Thanks for your help. This patch also works on SPARC Solaris 10. Thanks. Mass update RESOLVED->CLOSED after release of openssh-5.1 |