devpts filesystem

This filesystem lives purely in memory.

Each mount of the devpts filesystem is now distinct (each mount point are independent)

mount opts

ptmxmode

設定 /dev/pts/ptmx 的 permission, default 0000

mount -t devpts -o remount,rw,nosuid,noexec,relatime,uid=0,gid=5,mode=620,ptmxmode=0000 devpts /dev/pts

Setting

Total count of pty pairs in all instances is limited by sysctls:

kernel.pty.max = 4096       // global limit

kernel.pty.reserve = 1024   // reserved for filesystems mounted from the initial mount namespace

kernel.pty.nr               // current count of ptys