$ /opt/fb30ss/bin/isql -q
SQL> create database '/3333:/var/db/fb30/tmp201509201545.fdb';
SQL> recreate global temporary table gtt(id int);
SQL> commit;
SQL> insert into gtt select 1 from rdb$types;
Statement failed, SQLSTATE = 08001
I/O error during "open O_CREAT" operation for file ""
-Error while trying to create file
-No such file or directory
SQL> quit;

$ env|grep -i firebird_tmp
FIREBIRD_TMP=/tmp/firebird

$ ls -l /tmp
total 44
drwxr-xr-x 2 abrt     abrt     4096 Sep 13 17:28 abrt
drwxrwx--- 2 firebird firebird 4096 Sep 20 15:07 fb25sc
drwxrwx--- 2 firebird firebird 4096 Sep 12 13:04 fb25ss
drwxrwx--- 2 firebird firebird 4096 Sep 10 14:01 fb30gc
drwxrwx--- 2 firebird firebird 4096 Sep 19 18:40 fb30sc
drwxrwx--- 2 firebird firebird 4096 Sep 19 18:37 fb30ss
drwxr-xr-x 2 firebird firebird 4096 Sep 20 15:39 firebird
. . .

$ ls -l /tmp/firebird
total 48
-rw-rw---- 1 firebird firebird    4192 Sep 20 15:38 fb12_trace
-rw-rw---- 1 firebird firebird       0 Aug 25 19:56 fb_init
-rw-rw---- 1 firebird firebird       0 Sep 19 18:33 fb_lock_04080000000000004a0fe60000000000
-rw-rw---- 1 firebird firebird    4160 Sep 20 15:37 fb_trace
-rw-rw---- 1 firebird firebird    1144 Sep 10 13:43 fb_trace_5hh7HW
-rw-rw---- 1 firebird firebird       0 Sep 20 15:37 fb_trace_cQCsX7
-rw-rw---- 1 firebird firebird    4572 Sep 13 09:43 fb_trace_d9GpD8
-rw-rw---- 1 firebird firebird    1144 Sep 10 07:19 fb_trace_GHMn1V
-rw-rw---- 1 firebird firebird       0 Sep 10 19:32 fb_trace_KAFBL9
-rw-rw---- 1 firebird firebird    4573 Sep 12 08:52 fb_trace_ptXnjN
-rw-rw---- 1 firebird firebird       0 Sep 12 13:07 fb_trace_pz1rpn
-rw-rw---- 1 firebird firebird       0 Sep 10 20:29 fb_trace_wBiKYp
-rw-rw---- 1 firebird firebird    2530 Sep 10 19:12 fb_trace_wdAwpt
-rw-rw---- 1 firebird firebird       0 Sep 20 15:37 fb_trace_xADjk0
-rw-rw---- 1 firebird firebird       0 Sep 12 13:10 fb_trace_Y4TOnR
-rw-rw---- 1 firebird firebird 1048576 Sep 20 15:37 fb_user_mapping

$ ls -l / | grep tmp
drwxr-xr-x.  15 abrt abrt  36864 Sep 20 15:46 tmp

$ usermod -a -G abrt firebird
$ /etc/init.d/fb30sc restart
Stopping Firebird server [fb30sc]          [  OK  ]

Starting Firebird server [fb30sc]           [  OK  ]

$ /opt/fb30sc/bin/isql -q
SQL> create database '/3330:/var/db/fb30/tx001.fdb';
SQL> create global temporary table gtt(id int); commit;
SQL> insert into gtt select 1 from rdb$types;
SQL> commit;