> -----Original Message-----
> From: Mark Thomas <ma...@apache.org>
> Sent: Wednesday, November 18, 2020 3:03 AM
> To: users@tomcat.apache.org
> Subject: Re: Weirdest Tomcat Behavior Ever?
>
> On 13/11/2020 23:46, Mark Thomas wrote:
> > Eric sent me a copy of the strace (thanks Eric) and while it is
> > consistent with what has already been observed, it didn't provide any
> > new information on the socket / file descriptor being closed.
> >
> > I'd like to suggest running again with the following:
> >
> > sudo strace -r -f -e trace=network,desc -p <tomcat pid>
> >
> > That should log the file descriptor being closed (and other fd
> > activity). There are a couple of things we might be able to do with this:
> >
> > - we'll be able to determine if the socket is closed on the same or a
> > different thread
> > - we might be able to correlate the time of closure with other logs
> > (seems unlikely as we have this from Wireshark but you never know)
> > - the class before the close might be enlightening
>
> Hi Eric,
>
> I looked at the updated logs this morning. I don't see any additional logging
> for file descriptors in the strace output.
>
> I wonder if you need a slightly different command on your platform?
>
> I'd expect to see entries like this:
>
> [pid 8062] 0.000070 openat(AT_FDCWD,
> "/home/mark/repos/asf-tomcat-master/output/build/webapps/ROOT/bg-
> nav.png",
> O_RDONLY) = 57
> [pid 8062] 0.000027 fstat(57, <unfinished ...>
> [pid 8062] 0.000005 <... fstat resumed>{st_mode=S_IFREG|0664,
> st_size=1401, ...}) = 0
> [pid 8062] 0.000043 read(57, <unfinished ...>
> [pid 8062] 0.000033 <... read
> resumed>"\211PNG\r\n\32\n\0\0\0\rIHDR\0\0\0\n\0\0\0002\10\6\0\0\0e\3
> 3J".
> resumed>..,
> 1401) = 1401
> [pid 8062] 0.000013 close(57 <unfinished ...>
>
> showing file access although what I really want to see are the calls to close
> the sockets (like the last two in the sequence below from a test where I used
> telnet to perform an HTTP/1.0 request)
>
> pid 8069] 0.124099 <... accept resumed>{sa_family=AF_INET6,
> sin6_port=htons(52656), sin6_flowinfo=htonl(0), inet_pton(AF_INET6,
> "::ffff:127.0.0.1", &sin6_addr), sin6_scope_id=0}, [28]) = 50 ...
> [pid 8063] 0.000216 read(50, <unfinished ...>
> [pid 8063] 0.000058 <... read resumed>"GET / HTTP/1.0\r\n", 8192) = 16
> [pid 8063] 0.000029 read(50, <unfinished ...>
> [pid 8063] 0.000030 <... read resumed>0x7f4f6c000e70, 8192) = -1
> EAGAIN (Resource temporarily unavailable)
> [pid 8064] 0.001061 read(50, "Host: a\r\n", 8192) = 9
> [pid 8064] 0.000239 read(50, 0x7f4f60000e70, 8192) = -1 EAGAIN
> (Resource temporarily unavailable)
> [pid 8062] 0.000214 read(50, "\r\n", 8192) = 2
> [pid 8062] 0.007897 write(50, "HTTP/1.1 200 \r\nContent-Type:
> tex"..., 8192) = 8192
> [pid 8062] 0.000353 write(50, ">Tomcat Native</a></li>\n
> "..., 3079) = 3079
> [pid 8062] 0.002071 getsockopt(50, SOL_SOCKET, SO_LINGER,
> {l_onoff=0, l_linger=0}, [8]) = 0
> [pid 8062] 0.000102 shutdown(50, SHUT_WR) = 0
> [pid 8068] 0.000342 close(50) = 0
>
> It is probably worth running a couple of quick tests to figure out the correct
> form of the strace command on your platform and then retesting.
>
> Mark
>
Entirely my fault. I'm new to strace, so I didn't know what to expect. I have
now read the strace man page and I'm more up to speed. I tested it and we're
now capturing file descriptor operations. The next batch of logs will be better.
-Eric
Disclaimer : This email and any files transmitted with it are confidential and
intended solely for intended recipients. If you are not the named addressee you
should not disseminate, distribute, copy or alter this email. Any views or
opinions presented in this email are solely those of the author and might not
represent those of Physician Select Management. Warning: Although Physician
Select Management has taken reasonable precautions to ensure no viruses are
present in this email, the company cannot accept responsibility for any loss or
damage arising from the use of this email or attachments.
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org
For additional commands, e-mail: users-h...@tomcat.apache.org
