[lxc-devel] [lxd/master] util linux: implement mountpoint checking
brauner on Github
lxc-bot at linuxcontainers.org
Mon Oct 2 08:07:45 UTC 2017
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From e9bbbc352be9fece1f9b6e848e6bd03538caa116 Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brauner at ubuntu.com>
Date: Mon, 2 Oct 2017 10:05:17 +0200
Subject: [PATCH] util linux: implement mountpoint checking
The mountpoint -q tool simply looks at /proc/<pid>/mountinfo per default and
falls back to stat()ing the relevant path in case /proc/<pid>/mountinfo does
not exist. There's really no point in spawning a new subprocess for this. Let's
simply pars /proc/<pid>/mountinfo per default and fallback to stat()ing when
the file doesn't exist or is busted.
Closes #3877.
Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>
---
shared/util_linux.go | 33 ++++++++++++++++++++++++++-------
1 file changed, 26 insertions(+), 7 deletions(-)
diff --git a/shared/util_linux.go b/shared/util_linux.go
index 7560e44ac..229fe2713 100644
--- a/shared/util_linux.go
+++ b/shared/util_linux.go
@@ -335,15 +335,34 @@ func GetFileStat(p string) (uid int, gid int, major int, minor int,
return
}
-func IsMountPoint(name string) bool {
- _, err := exec.LookPath("mountpoint")
- if err == nil {
- _, err = RunCommand("mountpoint", "-q", name)
- if err != nil {
- return false
+func parseMountinfo(name string) int {
+ f, err := os.Open("/proc/self/mountinfo")
+ if err != nil {
+ return -1
+ }
+ defer f.Close()
+
+ scanner := bufio.NewScanner(f)
+ for scanner.Scan() {
+ line := scanner.Text()
+ tokens := strings.Fields(line)
+ if len(tokens) < 5 {
+ return -1
}
+ cleanPath := filepath.Clean(tokens[4])
+ cleanName := filepath.Clean(name)
+ if cleanPath == cleanName {
+ return 1
+ }
+ }
- return true
+ return 0
+}
+
+func IsMountPoint(name string) bool {
+ ret := parseMountinfo(name)
+ if ret >= 0 {
+ return (ret == 1)
}
stat, err := os.Stat(name)
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