bugattr - Bugs: bug #37027, attr_multi will never perform a...


bug #37027: attr_multi will never perform a remove operation with ATTR_OP_REMOVE

Submitted by:  None
Submitted on:  Sat 04 Aug 2012 02:47:54 PM UTC  
Category: NoneSeverity: 3 - Normal
Item Group: NoneStatus: None
Privacy: PublicAssigned to: None
Open/Closed: Open

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Sat 04 Aug 2012 02:47:54 PM UTC, original submission:

I've been trying to remove attributes by calling attr_multi, but according to strace the syscall getxattr is being called instead of removexattr.

Looking at the relevant files in package version 2.4.46 we have in include/attributes.h:


  • Valid values of am_opcode.

#define ATTR_OP_GET 1 /* return the indicated attr's value */
#define ATTR_OP_SET 2 /* set/create the indicated attr/value pair */
#define ATTR_OP_REMOVE 3 /* remove the indicated attr */

and in libattr/libattr.c:

static int
attr_single(const char path, attr_multiop_t op, int flags)
int r = -1;

errno = -EINVAL;
flags |= op->am_flags;
if (op->am_opcode & ATTR_OP_GET)
r = attr_get(path, op->am_attrname, op->am_attrvalue,
&op->am_length, flags);
else if (op->am_opcode & ATTR_OP_SET)
r = attr_set(path, op->am_attrname, op->am_attrvalue,
op->am_length, flags);
else if (op->am_opcode & ATTR_OP_REMOVE)
r = attr_remove(path, op->am_attrname, flags);
return r;

since ATTR_OP_GET & ATTR_OP_REMOVE == 1, the dispatching code above will never call the attr_remove() function. The code needs to either
- change the order of comparisons
- switch to comparing with == instead of bitbanging
- redefining ATTR_OP_REMOVE to 4 instead of 3.



(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

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