[Pgpool-hackers] md5 authentication hanging in daemon mode
Tatsuo Ishii
ishii at sraoss.co.jp
Tue May 17 15:24:01 UTC 2011
Thanks for finding the problem and sending patches. I will take care
of this.
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp
> When in daemon mode, connection hangs when using md5 authentication
> method. The child process in charge of the client goes into an infinite
> loop in pool_get_passwd() while trying to read the pool_passwd file.
>
> The cause of the problem comes from the daemonize() function that closes
> all file descriptors starting from 3, including the file descriptor of
> the pool_passwd file. When pgpool gets to pool_get_passwd, the null
> checks on the passwd_fd variable fail because the variable was not reset
> to a NULL value.
>
> The possible solution to this issue is to find and open the pool_passwd
> file after becoming a daemon. Please find the corresponding patch
> attached based on the pgpool-II V3_0_STABLE branch.
>
> Here are some informations on the status of pgpool-II while
> investigating the issue :
>
> $ ps xf
> 29960 ? Ss 0:00 pgpool -f
> /home/pgsql/pgpool-3.0_stable/etc/pgpool.conf -d
> 29961 ? T 0:35 \_ pgpool: accept connection
>
> 29962 ? S 0:00 \_ pgpool: wait for connection request
>
> 29963 ? S 0:00 \_ pgpool: wait for connection request
>
> 29964 ? S 0:00 \_ pgpool: wait for connection request
>
> 29965 ? S 0:00 \_ pgpool: PCP: wait for connection request
>
> 29966 ? S 0:00 \_ pgpool: worker process
>
>
> $ gdb --pid=29961
> (gdb) bt
> #0 0x00007f5fc98faea0 in read () from /lib/libc.so.6
> #1 0x00007f5fc98a5db8 in _IO_file_underflow () from /lib/libc.so.6
> #2 0x00007f5fc98a749e in _IO_default_uflow () from /lib/libc.so.6
> #3 0x00007f5fc989e97b in getc () from /lib/libc.so.6
> #4 0x0000000000447b6e in pool_get_passwd (username=0x22ef620
> "postgres") at pool_passwd.c:171
> #5 0x0000000000433cc4 in CheckMd5Auth (frontend=0x22f3270) at
> pool_hba.c:1453
> #6 ClientAuthentication (frontend=0x22f3270) at pool_hba.c:223
> #7 0x0000000000409980 in do_child (unix_fd=<value optimized out>,
> inet_fd=<value optimized out>)
> at child.c:244
> #8 0x0000000000403e85 in fork_a_child (unix_fd=3, inet_fd=4, id=0) at
> main.c:1032
> #9 0x0000000000406c0a in main (argc=<value optimized out>, argv=<value
> optimized out>) at main.c:516
>
>
> $ lsof -p 29961
> COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
> pgpool 29961 orgrim cwd DIR 254,1 1024 2 /
> pgpool 29961 orgrim rtd DIR 254,1 1024 2 /
> pgpool 29961 orgrim txt REG 254,6 2338135 2629903
> /home/pgsql/pgpool-3.0_stable/bin/pgpool
> pgpool 29961 orgrim mem REG 254,2 93936 390944
> /usr/lib/libz.so.1.2.3.4
> pgpool 29961 orgrim mem REG 254,1 14696 65843
> /lib/libdl-2.11.2.so
> pgpool 29961 orgrim mem REG 254,1 131260 65898
> /lib/libpthread-2.11.2.so
> pgpool 29961 orgrim mem REG 254,2 1853320 423215
> /usr/lib/libcrypto.so.1.0.0
> pgpool 29961 orgrim mem REG 254,2 337216 423216
> /usr/lib/libssl.so.1.0.0
> pgpool 29961 orgrim mem REG 254,1 1432968 65793
> /lib/libc-2.11.2.so
> pgpool 29961 orgrim mem REG 254,1 530736 65846
> /lib/libm-2.11.2.so
> pgpool 29961 orgrim mem REG 254,1 89064 65849
> /lib/libnsl-2.11.2.so
> pgpool 29961 orgrim mem REG 254,1 80712 65899
> /lib/libresolv-2.11.2.so
> pgpool 29961 orgrim mem REG 254,1 35104 65795
> /lib/libcrypt-2.11.2.so
> pgpool 29961 orgrim mem REG 254,6 87933 2629886
> /home/pgsql/pgpool-3.0_stable/lib/libpcp.so.0.0.0
> pgpool 29961 orgrim mem REG 254,6 180785 2627322
> /home/pgsql/postgresql-9.0.4/lib/libpq.so.5.3
> pgpool 29961 orgrim mem REG 254,1 128744 65624
> /lib/ld-2.11.2.so
> pgpool 29961 orgrim mem REG 0,4 360451
> /VE0-SYSV00000000 (stat: No such file or directory)
> pgpool 29961 orgrim mem REG 0,4 458758
> /VE0-SYSV00000000 (stat: No such file or directory)
> pgpool 29961 orgrim mem REG 0,4 425989
> /VE0-SYSV00000000 (stat: No such file or directory)
> pgpool 29961 orgrim mem REG 0,4 393220
> /VE0-SYSV00000000 (stat: No such file or directory)
> pgpool 29961 orgrim mem REG 0,4 327682
> /VE0-SYSV00000000 (stat: No such file or directory)
> pgpool 29961 orgrim 0u CHR 1,3 0t0 1400
> /dev/null
> pgpool 29961 orgrim 1u CHR 1,3 0t0 1400
> /dev/null
> pgpool 29961 orgrim 2u CHR 1,3 0t0 1400
> /dev/null
> pgpool 29961 orgrim 3u unix 0xffff8801343d7840 0t0 162244
> /tmp/.s.PGSQL.9999
> pgpool 29961 orgrim 4u IPv4 162246 0t0 TCP
> *:9999 (LISTEN)
> pgpool 29961 orgrim 5u IPv4 162443 0t0 TCP
> localhost:9999->localhost:45603 (ESTABLISHED)
>
> - --
> Nicolas Thauvin
> DBA
> http://www.dalibo.com
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