/*
 *  This patch fixes the performance issue observed while retrieving the 
 *  hrStorage parameters in systems with large number of mountpoints 
 *  parameters using snmpwalk. 
 *   
 *  This issue is happening due to the overhead of large number of 
 *  ioctl() system calls in getmntent() function called by the 
 *  Get_Next_HR_Filesys() function.
 *  We see that in the Get_Next_HR_Filesys() function, inorder to access 
 *  the last mountpoint, the /etc/mnttab is opened and we walk through 
 *  all the mnttab entries for all filesystems till the end. This is the 
 *  reason we find a large number of the MNTIOC_GETMNTENT ioctl() calls.  
 *
 *  To reduce the overhead of the getmntent() calls, we maintain a cache
 *  of all the /etc/mnttab entries and walk through the cache instead of 
 *  opening /etc/mnttab and walking all the entries for each mountpoint.
 */

--- net-snmp-5.4.1.orig/agent/mibgroup/host/hr_filesys.c	2007-05-18 11:08:01.000000000 -0700
+++ net-snmp-5.4.1/agent/mibgroup/host/hr_filesys.c	2012-08-17 01:23:04.781860694 -0700
@@ -31,6 +31,10 @@
 #include <sys/mount.h>
 #endif
 
+#ifdef solaris2
+#include <sys/stat.h>
+#endif
+
 #include <ctype.h>
 #if HAVE_STRING_H
 #include <string.h>
@@ -85,7 +89,11 @@
 #ifdef solaris2
 
 struct mnttab   HRFS_entry_struct;
-struct mnttab  *HRFS_entry = &HRFS_entry_struct;
+struct mnttab  *HRFS_entry;
+struct mnttab	*HRFS_list;
+static int fscount;
+static time_t last_access=-1;
+
 #define	HRFS_name	mnt_special
 #define	HRFS_mount	mnt_mountp
 #define	HRFS_type	mnt_fstype
@@ -563,6 +571,12 @@
 void
 Init_HR_FileSys(void)
 {
+#ifdef solaris2
+	char buf[512]={NULL};
+	int lines=0, i=0;
+	struct stat file_stat;
+#endif
+
 #if HAVE_GETFSSTAT
 #if defined(HAVE_STATVFS) && defined(__NetBSD__)
     fscount = getvfsstat(NULL, 0, ST_NOWAIT);
@@ -603,10 +617,62 @@
         }
     }
 #else
-    HRFS_index = 1;
-    if (fp != NULL)
-        fclose(fp);
-    fp = fopen(ETC_MNTTAB, "r");
+    	HRFS_index = 1;
+	if (fp != NULL)
+        	fclose(fp);
+#ifdef solaris2
+	HRFS_index = 0;
+	stat(ETC_MNTTAB, &file_stat);
+	if (last_access == -1 || last_access != file_stat.st_mtime) { 
+    		fp = fopen(ETC_MNTTAB, "r");
+		if(fp == NULL)
+		{
+			DEBUGMSGTL(("host/hr_filesys", "fopen failed for mnttab.\n"));
+			return;
+		}
+
+		while ( (fgets((char *)&buf,sizeof(buf),fp)) != NULL) {
+			lines++;
+		}	
+		fclose(fp);
+	
+		HRFS_list = (struct mnttab *) malloc (sizeof(struct mnttab) * lines);
+		
+		if(HRFS_list == NULL)
+		{
+			DEBUGMSGTL(("host/hr_filesys", "Memory allocation for mnttab cache failed.\n"));
+			return;
+		}				
+
+    		fp = fopen(ETC_MNTTAB, "r");
+		
+		if(fp == NULL)
+                {
+			DEBUGMSGTL(("host/hr_filesys", "fopen failed for mnttab.\n"));
+			free(HRFS_list);
+			return;
+                }
+
+		fscount = lines;
+		while (i < fscount)
+    		{
+			if (getmntent(fp, &HRFS_entry_struct) == 0)
+        		{
+				HRFS_list[i].mnt_special = strdup(HRFS_entry_struct.mnt_special);
+				HRFS_list[i].mnt_mountp = strdup(HRFS_entry_struct.mnt_mountp);
+				HRFS_list[i].mnt_fstype = strdup(HRFS_entry_struct.mnt_fstype);
+				HRFS_list[i].mnt_mntopts = strdup(HRFS_entry_struct.mnt_mntopts);
+        			i++;
+        		}
+    		}
+	
+		HRFS_entry = HRFS_list;
+		last_access = file_stat.st_mtime;
+	}
+#else    
+	fp = fopen(ETC_MNTTAB, "r");
+#endif
+
 #endif
 }
 
@@ -699,21 +765,24 @@
 #else
     const char    **cpp;
 
-    if (fp == NULL)
-        return -1;
 
 #ifdef solaris2
-    if (getmntent(fp, HRFS_entry) != 0)
-        return -1;
+
+	if (HRFS_index >= fscount)
+		return -1;
+	HRFS_entry = &HRFS_list[HRFS_index];
+		return ++HRFS_index;
+
 #else
-    HRFS_entry = getmntent(fp);
-    if (HRFS_entry == NULL)
-        return -1;
-#endif                          /* solaris2 */
+	if (fp == NULL)
+                return -1;
+        HRFS_entry = getmntent(fp);
+        if (HRFS_entry == NULL)
+                return -1;
 
-    for (cpp = HRFS_ignores; *cpp != NULL; ++cpp)
-        if (!strcmp(HRFS_entry->HRFS_type, *cpp))
-            return Get_Next_HR_FileSys();
+	for (cpp = HRFS_ignores; *cpp != NULL; ++cpp)
+		if (!strcmp(HRFS_entry->HRFS_type, *cpp))
+			return Get_Next_HR_FileSys();
 
     /*
      * Try and ensure that index values are persistent
@@ -728,6 +797,8 @@
     }
 
     return HRFS_index++;
+#endif
+
 #endif                          /* HAVE_GETFSSTAT */
 }
 
@@ -780,20 +851,34 @@
 End_HR_FileSys(void)
 {
 #ifdef HAVE_GETFSSTAT
-    if (fsstats)
-        free((char *) fsstats);
-    fsstats = NULL;
+	if (fsstats)
+		free((char *) fsstats);
+	fsstats = NULL;
 #elif defined(aix4) || defined(aix5)
-    if(aixmnt != NULL) {
-        free(aixmnt);
-        aixmnt = NULL;
-        aixcurr = NULL;
-        HRFS_entry = NULL;
-    }
-#else
-    if (fp != NULL)
-        fclose(fp);
-    fp = NULL;
+	if(aixmnt != NULL) {
+		free(aixmnt);
+		aixmnt = NULL;
+		aixcurr = NULL;
+		HRFS_entry = NULL;
+	}
+#else
+	int i=0;
+	if (fp != NULL)
+		fclose(fp);
+	fp = NULL;
+
+#ifdef solaris2
+	while (i < fscount) {
+		free(HRFS_list[i].mnt_special);
+		free(HRFS_list[i].mnt_mountp);
+		free(HRFS_list[i].mnt_fstype);
+		free(HRFS_list[i].mnt_mntopts);
+		i++;
+	}
+	if (HRFS_list != NULL)
+		free(HRFS_list);
+#endif
+
 #endif
 }