On Mon, Jan 16, 2017 at 11:41:05PM -0500, Theodore Ts'o wrote: > On Mon, Jan 16, 2017 at 04:46:45PM +0100, Jan Stancek wrote: > > 4.9 kernel and simple touch on immutable file gives me: > > utimensat(AT_FDCWD, "afile", NULL, 0) = -1 EPERM (Operation not permitted) > > > > while an older kernel it gives me: > > utimensat(AT_FDCWD, "afile", NULL, 0) = -1 EACCES (Permission denied) > > > > Do we need to update man page or fix kernel back to return EACCES? > > Quoting from: http://blog.unclesniper.org/archives/2-Linux-programmers,-learn-the-difference-between-EACCES-and-EPERM-already!.html > It appears that many programmers are unaware that there is a > fundamental difference between the error codes EACCES (aka > "Permission denied") and EPERM (aka "Operation not permitted"). In > particular, a lot of code returns EPERM when they really mean > EACCES: > > mist% killall sshd > sshd(2244): Operation not permitted That's posix, not just linux. > To clear this up: "Permission denied" means just that -- the > process has insufficient privileges to perform the requested > operation. Simply put, this means that "trying the same thing as > root will work". Where did this blog entry come from? I've never seen the ACCES/PERM distinction made that way anywhere else. Posix says: [EACCES] Permission denied. An attempt was made to access a file in a way forbidden by its file access permissions. [EPERM] Operation not permitted. An attempt was made to perform an operation limited to processes with appropriate privileges or to the owner of a file or other resource. So EPERM is exactly for attempts to do things that are reserved for root (or process with appropriate capabilities or whatever). --b. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
