[Freeipa-devel] [PATCHES 134-136] extdom: handle ERANGE return code for getXXYYY_r()

[Sumit Bose]

On Wed, Mar 04, 2015 at 06:14:53PM +0100, Sumit Bose wrote:
> On Wed, Mar 04, 2015 at 04:17:55PM +0200, Alexander Bokovoy wrote:
> > On Mon, 02 Mar 2015, Sumit Bose wrote:
> > >diff --git a/daemons/ipa-slapi-plugins/ipa-extdom-extop/ipa_extdom_common.c b/daemons/ipa-slapi-plugins/ipa-extdom-extop/ipa_extdom_common.c
> > >index 20fdd62b20f28f5384cf83b8be5819f721c6c3db..84aeb28066f25f05a89d0c2d42e8b060e2399501 100644
> > >--- a/daemons/ipa-slapi-plugins/ipa-extdom-extop/ipa_extdom_common.c
> > >+++ b/daemons/ipa-slapi-plugins/ipa-extdom-extop/ipa_extdom_common.c
> > >@@ -49,6 +49,220 @@
> > >
> > >#define MAX(a,b) (((a)>(b))?(a):(b))
> > >#define SSSD_DOMAIN_SEPARATOR '@'
> > >+#define MAX_BUF (1024*1024*1024)
> > >+
> > >+
> > >+
> > >+static int get_buffer(size_t *_buf_len, char **_buf)
> > >+{
> > >+    long pw_max;
> > >+    long gr_max;
> > >+    size_t buf_len;
> > >+    char *buf;
> > >+
> > >+    pw_max = sysconf(_SC_GETPW_R_SIZE_MAX);
> > >+    gr_max = sysconf(_SC_GETGR_R_SIZE_MAX);
> > >+
> > >+    if (pw_max == -1 && gr_max == -1) {
> > >+        buf_len = 16384;
> > >+    } else {
> > >+        buf_len = MAX(pw_max, gr_max);
> > >+    }
> > Here you'd get buf_len equal to 1024 by default on Linux which is too
> > low for our use case. I think it would be beneficial to add one more
> > MAX(buf_len, 16384):
> > -    if (pw_max == -1 && gr_max == -1) {
> > -        buf_len = 16384;
> > -    } else {
> > -        buf_len = MAX(pw_max, gr_max);
> > -    }
> > +    buf_len = MAX(16384, MAX(pw_max, gr_max));
> > 
> > with MAX(MAX(),..) you also get rid of if() statement as resulting
> > rvalue would be guaranteed to be positive.
> 
> done
> 
> > 
> > The rest is going along the common lines but would it be better to
> > allocate memory once per LDAP client request rather than always ask for
> > it per each NSS call? You can guarantee a sequential use of the buffer
> > within the LDAP client request processing so there is no problem with
> > locks but having this memory re-allocated on subsequent
> > getpwnam()/getpwuid()/... calls within the same request processing seems
> > suboptimal to me.
> 
> ok, makes sense, I moved get_buffer() back to the callers.
> 
> New version attached.

Please ignore this patch, I will send a revised version soon.

bye,
Sumit

> 
> bye,
> Sumit
> 
> > 
> > -- 
> > / Alexander Bokovoy