[Pvfs2-cvs] commit by pcarns in pvfs2-1/src/common/misc: pint-cached-config.c

[CVS commit program]

Update of /projects/cvsroot/pvfs2-1/src/common/misc
In directory parlweb1:/tmp/cvs-serv24886

Modified Files:
	pint-cached-config.c 
Log Message:
Introduce more noise into random seeding for PINT_cached_config interface().
Using time in seconds was prone to collision if many clients initialized
concurrently with NTP or some other time synchronization method. 


Index: pint-cached-config.c
===================================================================
RCS file: /projects/cvsroot/pvfs2-1/src/common/misc/pint-cached-config.c,v
diff -p -u -r1.24 -r1.25
--- pint-cached-config.c	16 May 2008 14:12:13 -0000	1.24
+++ pint-cached-config.c	19 May 2008 13:18:26 -0000	1.25
@@ -8,7 +8,10 @@
 #include <string.h>
 #include <assert.h>
 #include <stdlib.h>
+#include <sys/time.h>
 #include <time.h>
+#include <sys/types.h>
+#include <unistd.h>
 
 #include "pvfs2-types.h"
 #include "pvfs2-attr.h"
@@ -114,12 +117,41 @@ static int io_randomized = 0;
  */
 int PINT_cached_config_initialize(void)
 {
+    struct timeval tv;
+    unsigned int seed = 0;
+    char hostname[HOST_NAME_MAX];
+    int ret;
+    int i;
+    int hostnamelen;
+
     if (!PINT_fsid_config_cache_table)
     {
         PINT_fsid_config_cache_table =
             qhash_init(hash_fsid_compare,hash_fsid,11);
     }
-    srand((unsigned int)time(NULL));
+
+    /* include time, pid, and hostname in random seed in order to help avoid
+     * collisions on object placement when many clients are launched 
+     * concurrently 
+     */
+    gettimeofday(&tv, NULL);
+    seed += tv.tv_sec;
+    seed += tv.tv_usec;
+
+    seed += getpid();
+
+    ret = gethostname(hostname, HOST_NAME_MAX);
+    if(ret == 0)
+    {
+        hostnamelen = strlen(hostname);
+        for(i=0; i<hostnamelen; i++)
+        {
+            seed += (hostname[hostnamelen - i - 1] + i*256);
+        }
+    }
+    
+    srand(seed);
+
     return (PINT_fsid_config_cache_table ? 0 : -PVFS_ENOMEM);
 }