[GUACAMOLE-1625] Child processes inherit useless fd from parent processes

• Type: Improvement
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 1.4.0
• Component/s: guacd
• Assignee: Unassigned
• Reporter: luo
• Created: 22/Jun/22 11:55
• Updated: 23/Jun/22 02:31

Description

For example, if we open three ssh connections in a row, the subprocesses will have more and more fd, which is actually not necessary

Most fd's come from the socketpair() of the parent process

 

# ps aux | grep guacd
root      6453  0.0  0.3 522844 14756 pts/0    Sl+  19:24   0:00 guacd -f -Ldebug
root      6457  0.2  0.9 628436 37176 pts/0    Sl   19:24   0:00 guacd -f -Ldebug
root      6512  1.8  0.9 483508 38644 pts/0    Sl   19:31   0:00 guacd -f -Ldebug
root      6605  0.0  0.0  21540  1084 pts/2    S+   19:31   0:00 grep --color=auto guacd
# cd /proc/6512/fd
# ls
0  1  10  11  12  13  14  2  3  4  5  6  7  8  9
# ps aux | grep guacd
root      6453  0.0  0.3 678504 14756 pts/0    Sl+  19:24   0:00 guacd -f -Ldebug
root      6457  0.1  0.9 628436 37176 pts/0    Sl   19:24   0:00 guacd -f -Ldebug
root      6512  0.2  0.9 483508 38752 pts/0    Sl   19:31   0:00 guacd -f -Ldebug
root      6620  5.0  0.9 679600 38748 pts/0    Sl   19:31   0:00 guacd -f -Ldebug
root      6713  0.0  0.0  21540  1104 pts/2    S+   19:31   0:00 grep --color=auto guacd
# cd /proc/6620/fd
# ls
0  1  10  11  12  13  14  15  16  17  2  3  4  5  6  7  8  9
# ps aux | grep guacd
root      6453  0.0  0.3 703092 14756 pts/0    Sl+  19:24   0:00 guacd -f -Ldebug
root      6457  0.1  0.9 628436 37176 pts/0    Sl   19:24   0:00 guacd -f -Ldebug
root      6512  0.1  0.9 483508 38752 pts/0    Sl   19:31   0:00 guacd -f -Ldebug
root      6620  0.3  0.9 679600 38748 pts/0    Sl   19:31   0:00 guacd -f -Ldebug
root      6720  1.2  0.9 761528 38804 pts/0    Sl   19:31   0:00 guacd -f -Ldebug
root      6813  0.0  0.0  21540  1148 pts/2    S+   19:31   0:00 grep --color=auto guacd
# cd /proc/6720/fd
# ls
0  1  10  11  12  13  14  15  16  17  18  19  2  20  3  4  5  6  7  8  9 

This may cause libvncserver to fail using select() if the useless fd is larger than FD_SETSIZE