svn commit: r195243 - head/bin/chmod
Edward Tomasz Napierala
trasz at FreeBSD.org
Wed Jul 1 15:52:20 UTC 2009
Author: trasz
Date: Wed Jul 1 15:52:19 2009
New Revision: 195243
URL: http://svn.freebsd.org/changeset/base/195243
Log:
With NFSv4 ACLs, it is possible that applying a mode to an ACL which
is identical to the mode computed from that ACL will modify the ACL.
For example, mode computed from the following ACL is 0600:
user:kamila:rwx--------C--:------:allow
owner@:--x-----------:------:deny
owner@:rw-p---A-W-Co-:------:allow
group@:rwxp----------:------:deny
group@:--------------:------:allow
everyone@:rwxp---A-W-Co-:------:deny
everyone@:------a-R-c--s:------:allow
However, applying that mode (chmod 0600) changes the ACL into this:
user:kamila:rwx-----------:------:deny
user:kamila:rwx--------C--:------:allow
owner@:--x-----------:------:deny
owner@:rw-p---A-W-Co-:------:allow
group@:rwxp----------:------:deny
group@:--------------:------:allow
everyone@:rwxp---A-W-Co-:------:deny
everyone@:------a-R-c--s:------:allow
In chmod(1) utility, there is an optimisation, which makes it not
call chmod(2) if the mode of the file is the same as the new mode.
Disable that optimisation for files which may have NFSv4 ACLs.
Reviewed by: rwatson
Approved by: re (kib)
Modified:
head/bin/chmod/chmod.c
Modified: head/bin/chmod/chmod.c
==============================================================================
--- head/bin/chmod/chmod.c Wed Jul 1 15:37:23 2009 (r195242)
+++ head/bin/chmod/chmod.c Wed Jul 1 15:52:19 2009 (r195243)
@@ -54,6 +54,7 @@ __FBSDID("$FreeBSD$");
#include <unistd.h>
static void usage(void);
+static int may_have_nfs4acl(const FTSENT *ent);
int
main(int argc, char *argv[])
@@ -180,8 +181,14 @@ done: argv += optind;
break;
}
newmode = getmode(set, p->fts_statp->st_mode);
- if ((newmode & ALLPERMS) == (p->fts_statp->st_mode & ALLPERMS))
- continue;
+ /*
+ * With NFSv4 ACLs, it is possible that applying a mode
+ * identical to the one computed from an ACL will change
+ * that ACL.
+ */
+ if (may_have_nfs4acl(p) == 0 &&
+ (newmode & ALLPERMS) == (p->fts_statp->st_mode & ALLPERMS))
+ continue;
if ((*change_mode)(p->fts_accpath, newmode) && !fflag) {
warn("%s", p->fts_path);
rval = 1;
@@ -219,3 +226,24 @@ usage(void)
"usage: chmod [-fhv] [-R [-H | -L | -P]] mode file ...\n");
exit(1);
}
+
+static int
+may_have_nfs4acl(const FTSENT *ent)
+{
+ int ret;
+ static dev_t previous_dev = (dev_t)-1;
+ static int supports_acls = -1;
+
+ if (previous_dev != ent->fts_statp->st_dev) {
+ previous_dev = ent->fts_statp->st_dev;
+ supports_acls = 0;
+
+ ret = pathconf(ent->fts_accpath, _PC_ACL_NFS4);
+ if (ret > 0)
+ supports_acls = 1;
+ else if (ret < 0 && errno != EINVAL)
+ warn("%s", ent->fts_path);
+ }
+
+ return (supports_acls);
+}
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