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Unlike on Unix, a Windows process's exit status is a DWORD, i.e. a 32-bit unsigned integer. And exit statuses seen in practice can range up into the high half of that space. For example, if a process dies of an 'illegal instruction' exception, then the exit status retrieved by GetExitCodeProcess will be 0xC000001D == STATUS_ILLEGAL_INSTRUCTION. If this happens to the process running inside pterm.exe, then conpty->exitstatus will be set to a value greater than INT_MAX, which will cause conpty_exitcode to return -1. Unfortunately, a -1 return from conpty_exitstatus is treated by front ends as saying that the backend process hasn't exited yet, and is still running. So pterm will sit around after its subprocess has already terminated, contrary to your 'close on exit' setting. Moreover, when cmd.exe exits, it apparently passes on to its parent process the exit status of the last subcommand it ran. So if you run a Windows pterm containing an ordinary interactive console session, and the last subprogram you happen to run inside that session dies of a fatal signal, then the same thing will happen after you type 'exit' at the command prompt. This has been happening to me intermittently ever since I created pterm.exe in the first place, and I guessed completely wrong about the cause (I feared some kind of subtle race condition in pterm's use of the process API). I've only just managed to reproduce it reliably enough to debug, and I'm relieved to find it's much simpler than that! The immediate fix, in any case, is to ensure we don't return -1 from conpty_exitcode unless the process really is still running. And don't return INT_MAX either, because that indicates 'unclean exit' in a way that triggers 'close window only on clean exit' (and even Unix pterm doesn't consider the primary subprocess dying of a signal to count as unclean). So we clip all out-of-range Windows exception codes to INT_MAX-1. In the longer term I think it would be nice to turn exit codes into a full 32-bit space, and move the special values completely out of it. That would permit actually keeping the exact exception code and passing it on to a caller who needed it. For example, if we were to write a Windows psusan (which I could imagine being occasionally useful), this way it would be able to return the unmodified full Windows exit code via the "exit-status" chanreq. But I don't think we currently have any clients needing that much detail, so that's a more intrusive cleanup for a later date. |
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|---|---|---|
| charset | ||
| cmake | ||
| contrib | ||
| crypto | ||
| doc | ||
| icons | ||
| keygen | ||
| otherbackends | ||
| proxy | ||
| ssh | ||
| stubs | ||
| terminal | ||
| test | ||
| unix | ||
| utils | ||
| windows | ||
| .gitignore | ||
| aqsync.c | ||
| be_list.c | ||
| Buildscr | ||
| Buildscr.cv | ||
| callback.c | ||
| cgtest.c | ||
| CHECKLST.txt | ||
| clicons.c | ||
| CMakeLists.txt | ||
| cmdgen.c | ||
| cmdline.c | ||
| config.c | ||
| console.c | ||
| console.h | ||
| defs.h | ||
| dialog.c | ||
| dialog.h | ||
| errsock.c | ||
| import.c | ||
| LATEST.VER | ||
| ldisc.c | ||
| LICENCE | ||
| licence.pl | ||
| logging.c | ||
| marshal.h | ||
| misc.h | ||
| mksrcarc.sh | ||
| mkunxarc.sh | ||
| mpint.h | ||
| network.h | ||
| pageant.c | ||
| pageant.h | ||
| pinger.c | ||
| pscp.c | ||
| psftp.c | ||
| psftp.h | ||
| psftpcommon.c | ||
| psocks.c | ||
| psocks.h | ||
| putty.h | ||
| puttymem.h | ||
| README | ||
| release.pl | ||
| settings.c | ||
| sign.sh | ||
| ssh.h | ||
| sshcr.h | ||
| sshkeygen.h | ||
| sshpubk.c | ||
| sshrand.c | ||
| storage.h | ||
| timing.c | ||
| tree234.h | ||
| version.h | ||
| x11disp.c | ||
This is the README for PuTTY, a free Windows and Unix Telnet and SSH
client.
PuTTY is built using CMake <https://cmake.org/>. To compile in the
simplest way (on any of Linux, Windows or Mac), run these commands in
the source directory:
cmake .
cmake --build .
Documentation (in various formats including Windows Help and Unix
`man' pages) is built from the Halibut (`.but') files in the `doc'
subdirectory using `doc/Makefile'. If you aren't using one of our
source snapshots, you'll need to do this yourself. Halibut can be
found at <https://www.chiark.greenend.org.uk/~sgtatham/halibut/>.
The PuTTY home web site is
https://www.chiark.greenend.org.uk/~sgtatham/putty/
If you want to send bug reports or feature requests, please read the
Feedback section of the web site before doing so. Sending one-line
reports saying `it doesn't work' will waste your time as much as
ours.
See the file LICENCE for the licence conditions.