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syscallcompat: untangle Openat flag check

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Check for O_NWFOLLOW and O_EXCL separately to
make the logic clearer.
This commit is contained in:
Jakob Unterwurzacher 2018-09-22 19:38:47 +02:00
parent 9e6ee47bc9
commit 737a2f2012
1 changed files with 12 additions and 4 deletions
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16
internal/syscallcompat/sys_linux.go
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@ -58,10 +58,18 @@ func Fallocate(fd int, mode uint32, off int64, len int64) (err error) {
// Openat wraps the Openat syscall.
func Openat(dirfd int, path string, flags int, mode uint32) (fd int, err error) {
// Why would we ever want to call this without O_NOFOLLOW and O_EXCL?
if !(flags&syscall.O_CREAT != 0 && flags&syscall.O_EXCL != 0) && flags&syscall.O_NOFOLLOW == 0 {
tlog.Warn.Printf("Openat: adding missing O_NOFOLLOW flag")
flags |= syscall.O_NOFOLLOW
if flags&syscall.O_CREAT != 0 {
// O_CREAT should be used with O_EXCL. O_NOFOLLOW has no effect with O_EXCL.
if flags&syscall.O_EXCL == 0 {
tlog.Warn.Printf("Openat: O_CREAT without O_EXCL: flags = %#x", flags)
flags |= syscall.O_EXCL
}
} else {
// If O_CREAT is not used, we should use O_NOFOLLOW
if flags&syscall.O_NOFOLLOW == 0 {
tlog.Warn.Printf("Openat: O_NOFOLLOW missing: flags = %#x", flags)
flags |= syscall.O_NOFOLLOW
}
}
return syscall.Openat(dirfd, path, flags, mode)
}