[pgpool-hackers: 4462] Segmentation fault on error at parsing config file

[Carlos Chapi]

If there's a syntax error in pgpool.conf like:

listen_addresses = '*

(without closing single quotes) trying to start pgpool results in a
Segmentation Fault instead of a parsing error. Here's the backtrace:

Core was generated by `/usr/bin/pgpool -f /etc/pgpool-II/pgpool.conf -n'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  pfree (pointer=0x7f524ce70bc0) at parser/../../src/utils/mmgr/mcxt.c:956
956             (*context->methods->free_p) (context, pointer);
(gdb) bt full
#0  pfree (pointer=0x7f524ce70bc0) at parser/../../src/utils/mmgr/mcxt.c:956
        context = 0x0
#1  FreeConfigVariable (item=0x7f524ce70c08) at config/pool_config.l:287
No locals.
#2  FreeConfigVariables (list=<optimized out>) at config/pool_config.l:305
        next = 0x0
        item = 0x7f524ce70c08
#3  ParseConfigFile (config_file=<optimized out>,
calling_file=calling_file at entry=0x0, depth=depth at entry=0,
elevel=elevel at entry=21, head_p=head_p at entry=0x7ffc7a650d50,
tail_p=tail_p at entry=0x7ffc7a650d48) at config/pool_config.l:465
        fd = 0x560db343af50
        lex_buffer = 0x560db343b130
        token = 8
        key = <optimized out>
        val = <optimized out>
        item = <optimized out>
        buf = "/etc/pgpool-II\000pgpool.conf", '\000' <repeats 5998
times>...
        config_filepath = 0x7f524ce70b00 "/etc/pgpool-II/pgpool.conf"
#4  0x0000560db2501e2a in pool_get_config (config_file=<optimized out>,
context=CFGCXT_INIT) at config/pool_config.l:485
        head_p = 0x7f524ce70b90
        tail_p = 0x7f524ce70c08
        res = <optimized out>
        elevel = 21
#5  0x0000560db24f1417 in main (argc=<optimized out>, argv=<optimized out>)
at main/main.c:231
        opt = <optimized out>
        debug_level = 0
        optindex = 0
        discard_status = 0 '\000'
        clear_memcache_oidmaps = 0 '\000'
        pcp_conf_file_path = "/etc/pgpool-II/pcp.conf", '\000' <repeats
8169 times>
        conf_file_path = "/etc/pgpool-II/pgpool.conf", '\000' <repeats 8166
times>
        hba_file_path = "/etc/pgpool-II/pool_hba.conf", '\000' <repeats
8164 times>
        pool_passwd_key_file_path = '\000' <repeats 2856 times>...
        long_options = {{name = 0x560db25ea865 "hba-file", has_arg = 1,
flag = 0x0, val = 97}, {name = 0x560db25e98d3 "debug", has_arg = 0, flag =
0x0, val = 100}, {name = 0x560db25ea86e "config-file", has_arg = 1, flag =
0x0, val = 102}, {
            name = 0x560db25ea87a "key-file", has_arg = 1, flag = 0x0, val
= 107}, {name = 0x560db25ea883 "pcp-file", has_arg = 1, flag = 0x0, val =
70}, {name = 0x560db25ea88c "help", has_arg = 0, flag = 0x0, val = 104},
{name = 0x560db25ea606 "mode", has_arg = 1,
            flag = 0x0, val = 109}, {name = 0x560db25ea891 "dont-detach",
has_arg = 0, flag = 0x0, val = 110}, {name = 0x560db25ea89d
"discard-status", has_arg = 0, flag = 0x0, val = 68}, {name =
0x560db25ea8ac "clear-oidmaps", has_arg = 0, flag = 0x0, val = 67}, {
            name = 0x560db25ea8ba "debug-assertions", has_arg = 0, flag =
0x0, val = 120}, {name = 0x560db25fbb8b "version", has_arg = 0, flag = 0x0,
val = 118}, {name = 0x0, has_arg = 0, flag = 0x0, val = 0}}

It seems this was introduced on this commit:

https://git.postgresql.org/gitweb/?p=pgpool2.git;a=commit;h=25d05e55e6ebf334e768a9b454ecdb84a8a4054d

I have attached a patch to mitigate this, but I'm not entirely sure if it's
the right approach to avoiding the (possible?) memory leak with the "key"
pointer.

I'll appreciate it if anyone can take a look at the patch or the issue
overall.

Thanks,


--
Carlos Chapi
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