What Bruno said, plus:
On 2023-05-01 12:43, Ondrej Valousek wrote:
+/* Return 1 if ATTR is found in the xattr list given by BUF */
+int have_xattr (char const *attr, char *buf, ssize_t buflen)
This returns 1 or 0 so let's have it return bool instead. Also, it
doesn't modify the buffer (or at least, it won't once you get rid of the
'free'), so change it to 'char const *buf'.
+ int keylen;
This should be size_t, not int. Also, declare it when initialized, not here.
+ if (strcmp (key, attr) == 0)
+ {
+ /* we don't expect this function will be called again
+ so we free the buffer so caller does not have to */
+ free (buf);
+ return 1;
+ }
+ keylen = strlen (key) + 1;
I found have_xattr a bit confusing. How about something like this instead?
static bool
have_xattr (char const *attr, char const *buf, ssize_t buflen)
{
char const *key = buf;
char const *buflim = buf + buflen;
for (char const *key = buf; key < buflim; key += strlen (key) + 1)
if (strcmp (key, attr) == 0)
return true;
return false;
}
+ attrlist = malloc (ret);
+ if (attrlist == NULL)
+ return -1;
+ buflen = listxattr (name, attrlist, ret);
Shouldn't this be llistxattr, not listxattr?
Let's declare attrlist and buflen when initialized, e.g., "char
*attrlist = malloc (ret);".
+ if (buflen == -1)
This should be "buflen < 0".
More important, there's a race condition here, as someone could add
attributes to the file between the two listxattr calls. So I suggest
using this algorithm instead:
* Do not use llistxattr (name, NULL, 0). Instead, invoke llistxattr on a
small (say, 3 KiB) buffer on the stack. Use malloc only if llistxattr
returns ERANGE, and keep expanding this buffer (via free-then-malloc,
not realloc, since you don't need to save the old storage) while
llistxattr returns ERANGE. Check for integer overflow when multiplying
the buffer size by 1.5, by using ckd_add. Use 'free' at the end only if
we used 'malloc'.
+ if(have_xattr (XATTR_NAME_POSIX_ACL_ACCESS, attrlist, buflen))
return 1;
+ else
+ ret = 0;
Omit "else".
+ if (have_xattr (XATTR_NAME_POSIX_ACL_DEFAULT, attrlist, buflen))
return 1;
+ else
+ ret = 0;
RET is already zero here, so omit "else ret = 0;".
- if (ret < 0)
+ if (have_xattr (XATTR_NAME_NFSV4_ACL, attrlist, buflen))
{
/* Check for NFSv4 ACLs. The max length of a trivial
ACL is 6 words for owner, 6 for group, 7 for everyone,
The "if" part here goes on to call getxattr, but we don't want that as
it's both slower and a race condition: we want the attribute we already
got via llistxattr.
