Mount
當 fstab 有 1777 時，為什麼 /tmp 以權限 0755 掛載？
對於
/tmpin/etc/fstab，我有mode=1777，但重新啟動後，權限/tmp為0755。另一個目錄/var/tmp的配置方式完全相同，但沒有這個問題（見下文）。這是一個執行 Ubuntu 18.04 伺服器的樹莓派。根文件系統是一個只讀安裝的 microSD 卡。使
1777權限永久化的正確方法是什麼？以下是一些額外的細節（重新啟動後）：
$ touch /tmp/test touch: cannot touch '/tmp/test': Permission denied $ whoami ubuntu $ ls -ld /tmp /var/tmp drwxr-xr-x 9 root root 180 Dec 26 13:54 /tmp drwxrwxrwt 4 root root 80 Dec 26 13:54 /var/tmp $ mount |grep /tmp tmpfs on /var/tmp type tmpfs (rw,nosuid,nodev,noexec,noatime,size=65536k) tmpfs on /tmp type tmpfs (rw,nosuid,nodev,noexec,noatime,size=131072k) $ grep /tmp /etc/fstab tmpfs /var/tmp tmpfs defaults,noatime,nosuid,nodev,noexec,mode=1777,size=64M 0 0 tmpfs /tmp tmpfs defaults,noatime,nosuid,nodev,noexec,mode=1777,size=128M 0 0 $ sudo systemctl status tmp.mount ● tmp.mount - /tmp Loaded: loaded (/etc/fstab; generated) Active: active (mounted) since Sun 2018-01-28 15:58:18 UTC; 10 months 27 days ago Where: /tmp What: tmpfs Docs: man:fstab(5) man:systemd-fstab-generator(8) Process: 642 ExecMount=/bin/mount tmpfs /tmp -t tmpfs -o defaults,noatime,nosuid,nodev,noexec,mode=1777,size=128M (code=exited, status=0/SUCCESS) Tasks: 0 (limit: 2146) CGroup: /system.slice/tmp.mount Jan 28 15:58:18 testsystem systemd[1]: Mounting /tmp... Jan 28 15:58:18 testsystem systemd[1]: Mounted /tmp. $ grep -R '/tmp' /etc/tmpfiles.d /usr/lib/tmpfiles.d /usr/lib/tmpfiles.d/x11.conf:D! /tmp/.X11-unix 1777 root root 10d /usr/lib/tmpfiles.d/x11.conf:D! /tmp/.ICE-unix 1777 root root 10d /usr/lib/tmpfiles.d/x11.conf:D! /tmp/.XIM-unix 1777 root root 10d /usr/lib/tmpfiles.d/x11.conf:D! /tmp/.font-unix 1777 root root 10d /usr/lib/tmpfiles.d/x11.conf:D! /tmp/.Test-unix 1777 root root 10d /usr/lib/tmpfiles.d/x11.conf:r! /tmp/.X[0-9]*-lock /usr/lib/tmpfiles.d/tmp.conf:D /tmp 1777 root root - /usr/lib/tmpfiles.d/tmp.conf:#q /var/tmp 1777 root root 30d /usr/lib/tmpfiles.d/tmp.conf:x /tmp/systemd-private-%b-* /usr/lib/tmpfiles.d/tmp.conf:X /tmp/systemd-private-%b-*/tmp /usr/lib/tmpfiles.d/tmp.conf:x /var/tmp/systemd-private-%b-* /usr/lib/tmpfiles.d/tmp.conf:X /var/tmp/systemd-private-%b-*/tmp /usr/lib/tmpfiles.d/tmp.conf:R! /tmp/systemd-private-* /usr/lib/tmpfiles.d/tmp.conf:R! /var/tmp/systemd-private-* $ sudo chmod 1777 /tmp $ ls -ld /tmp /var/tmp drwxrwxrwt 9 root root 180 Dec 26 13:55 /tmp drwxrwxrwt 4 root root 80 Dec 26 13:55 /var/tmp $ cat /etc/rc.local #!/bin/bash service ntp start exit 0 $ uname -a Linux testsystem 4.15.0-1030-raspi2 #32-Ubuntu SMP PREEMPT Fri Dec 7 09:15:28 UTC 2018 armv7l armv7l armv7l GNU/Linux相關的未回答問題：
這是我初始配置的一部分（因為
/以只讀方式安裝）：sudo rm -rf /var/spool && sudo ln -s /tmp /var/spool顯然在啟動時，系統確實如此
chmod 755 /var/spool，這/tmp在我的情況下發生了變化。修復方法是用普通目錄替換符號連結並添加第三個
tmpfs掛載：sudo rm -rf /var/spool && sudo mkdir /var/spool && sudo chmod 755 /var/spool echo 'tmpfs /var/spool tmpfs defaults,noatime,nosuid,nodev,noexec,mode=0755,size=64M 0 0' |sudo tee -a /etc/fstab感謝大家的評論，這些評論將我引向了正確的方向，尤其是 Filipe Brandenburger 的“你有任何其他腳本或單元在啟動時與 /tmp 混淆嗎？”