Re: access(2): document EPERM error value

Hello Todd,

On 11/28/21 16:39, Todd C. Miller wrote:

I'm sending this via email rather than bugzilla as it is a fairly
trivial change.

If a file/directory has the immutable flag set, access/faccessat
will return EPERM if write access is requested.  This is not currently
documented, presumably because it is Linux-specific (though BSD has
similar behavior that is documented).  Perhaps something like the
following in the ERRORS section.

EPERM	Write permission was requested and pathname has the immutable
	flag set.  (See also ioctl_iflags(2).)

Also perhaps add ioctl_iflags(2) to the SEE ALSO section.

This came up in reference to:
     https://github.com/sudo-project/sudo/issues/122

Thanks for the report!
I applied the following.

Cheers,
Alex

---
     access.2: Document EPERM error code

     [Todd]:

     If a file/directory has the immutable flag set, access/faccessat
     will return EPERM if write access is requested.  This is not
     currently documented, presumably because it is Linux-specific
     (though BSD has similar behavior that is documented).  Perhaps
     something like the following in the ERRORS section.

     EPERM   Write permission was requested and pathname has the
             immutable flag set.  (See also ioctl_iflags(2).)

     Also perhaps add ioctl_iflags(2) to the SEE ALSO section.

     This came up in reference to:
     <https://github.com/sudo-project/sudo/issues/122>

     Reported-by: "Todd C. Miller" [off-list ref]
     Signed-off-by: Alejandro Colomar [off-list ref]

diff --git a/man2/access.2 b/man2/access.2
index 3b3992488..6c084826e 100644
--- a/man2/access.2
+++ b/man2/access.2

@@ -280,6 +280,11 @@ is relative and
  .I dirfd
  is a file descriptor referring to a file other than a directory.
  .TP
+.B EPERM
+Write permission was requested to a file that has the immutable flag set.
+See also
+.BR ioctl_iflags (2).
+.TP
  .B EROFS
  Write permission was requested for a file on a read-only filesystem.
  .TP

-- 
Alejandro Colomar
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/