make MAP_PRIVATE conditional on AIX not being defined ... should fix part of #216

[rrdtool.git] / src / rrd_open.c

diff --git a/src/rrd_open.c b/src/rrd_open.c
index f262413..5f3723f 100644 (file)
--- a/src/rrd_open.c
+++ b/src/rrd_open.c
@@ -1,5 +1,5 @@
 /*****************************************************************************
 /*****************************************************************************

- * RRDtool 1.3.2  Copyright by Tobi Oetiker, 1997-2008
+ * RRDtool 1.4.3  Copyright by Tobi Oetiker, 1997-2010

  *****************************************************************************
  * rrd_open.c  Open an RRD File
  *****************************************************************************
  *****************************************************************************
  * rrd_open.c  Open an RRD File
  *****************************************************************************


@@ -8,8 +8,36 @@
 
 #include "rrd_tool.h"
 #include "unused.h"
 
 #include "rrd_tool.h"
 #include "unused.h"

+
+#ifdef WIN32
+#include <stdlib.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#endif
+
+
+#ifdef HAVE_BROKEN_MS_ASYNC
+#include <sys/types.h>
+#include <utime.h>
+#endif
+

 #define MEMBLK 8192
 
 #define MEMBLK 8192
 

+#ifdef WIN32
+#define        _LK_UNLCK       0       /* Unlock */
+#define        _LK_LOCK        1       /* Lock */
+#define        _LK_NBLCK       2       /* Non-blocking lock */
+#define        _LK_RLCK        3       /* Lock for read only */
+#define        _LK_NBRLCK      4       /* Non-blocking lock for read only */
+
+
+#define        LK_UNLCK        _LK_UNLCK
+#define        LK_LOCK         _LK_LOCK
+#define        LK_NBLCK        _LK_NBLCK
+#define        LK_RLCK         _LK_RLCK
+#define        LK_NBRLCK       _LK_NBRLCK
+#endif
+

 /* DEBUG 2 prints information obtained via mincore(2) */
 #define DEBUG 1
 /* do not calculate exact madvise hints but assume 1 page for headers and
 /* DEBUG 2 prints information obtained via mincore(2) */
 #define DEBUG 1
 /* do not calculate exact madvise hints but assume 1 page for headers and


@@ -34,11 +62,11 @@
 #define __rrd_read(dst, dst_t, cnt) { \
        size_t wanted = sizeof(dst_t)*(cnt); \
         size_t got; \
 #define __rrd_read(dst, dst_t, cnt) { \
        size_t wanted = sizeof(dst_t)*(cnt); \
         size_t got; \

-       if ((dst = malloc(wanted)) == NULL) { \
+       if ((dst = (dst_t*)malloc(wanted)) == NULL) { \

                rrd_set_error(#dst " malloc"); \
                goto out_nullify_head; \
        } \
                rrd_set_error(#dst " malloc"); \
                goto out_nullify_head; \
        } \

-        got = read (rrd_file->fd, dst, wanted); \
+        got = read (rrd_simple_file->fd, dst, wanted); \

        if (got != wanted) { \
                rrd_set_error("short read while reading header " #dst); \
                 goto out_nullify_head; \
        if (got != wanted) { \
                rrd_set_error("short read while reading header " #dst); \
                 goto out_nullify_head; \


@@ -58,6 +86,10 @@
  * positioned to the first cdp in the first rra.
  * In the error path of rrd_open, only rrd_free(&rrd) has to be called
  * before returning an error. Do not call rrd_close upon failure of rrd_open.
  * positioned to the first cdp in the first rra.
  * In the error path of rrd_open, only rrd_free(&rrd) has to be called
  * before returning an error. Do not call rrd_close upon failure of rrd_open.

+ * If creating a new file, the parameter rrd must be initialised with
+ * details of the file content.
+ * If opening an existing file, then use rrd must be initialised by
+ * rrd_init(rrd) prior to invoking rrd_open

  */
 
 rrd_file_t *rrd_open(
  */
 
 rrd_file_t *rrd_open(


@@ -65,34 +97,50 @@ rrd_file_t *rrd_open(
     rrd_t *rrd,
     unsigned rdwr)
 {
     rrd_t *rrd,
     unsigned rdwr)
 {

+    unsigned long ui;

     int       flags = 0;
     int       flags = 0;

-    mode_t    mode = S_IRUSR;

     int       version;
 
 #ifdef HAVE_MMAP
     ssize_t   _page_size = sysconf(_SC_PAGESIZE);
     int       version;
 
 #ifdef HAVE_MMAP
     ssize_t   _page_size = sysconf(_SC_PAGESIZE);

-    int       mm_prot = PROT_READ, mm_flags = 0;

     char     *data = MAP_FAILED;
 #endif
     off_t     offset = 0;
     struct stat statb;
     rrd_file_t *rrd_file = NULL;
     char     *data = MAP_FAILED;
 #endif
     off_t     offset = 0;
     struct stat statb;
     rrd_file_t *rrd_file = NULL;

-    off_t     newfile_size = 0;
+    rrd_simple_file_t *rrd_simple_file = NULL;
+    size_t     newfile_size = 0;
+    size_t header_len, value_cnt, data_len;

 
 

-    if (rdwr & RRD_CREAT) {
-        /* yes bad inline signaling alert, we are using the
-           floatcookie to pass the size in ... only used in resize */
-        newfile_size = (off_t) rrd->stat_head->float_cookie;
-        free(rrd->stat_head);
+    /* Are we creating a new file? */
+    if((rdwr & RRD_CREAT) && (rrd->stat_head != NULL))
+    {
+        header_len = rrd_get_header_size(rrd);
+
+        value_cnt = 0;
+        for (ui = 0; ui < rrd->stat_head->rra_cnt; ui++)
+            value_cnt += rrd->stat_head->ds_cnt * rrd->rra_def[ui].row_cnt;
+
+        data_len = sizeof(rrd_value_t) * value_cnt;
+
+        newfile_size = header_len + data_len;

     }
     }

-    rrd_init(rrd);
-    rrd_file = malloc(sizeof(rrd_file_t));
+    
+    rrd_file = (rrd_file_t*)malloc(sizeof(rrd_file_t));

     if (rrd_file == NULL) {
         rrd_set_error("allocating rrd_file descriptor for '%s'", file_name);
         return NULL;
     }
     memset(rrd_file, 0, sizeof(rrd_file_t));
 
     if (rrd_file == NULL) {
         rrd_set_error("allocating rrd_file descriptor for '%s'", file_name);
         return NULL;
     }
     memset(rrd_file, 0, sizeof(rrd_file_t));
 

+    rrd_file->pvt = malloc(sizeof(rrd_simple_file_t));
+    if(rrd_file->pvt == NULL) {
+        rrd_set_error("allocating rrd_simple_file for '%s'", file_name);
+        return NULL;
+    }
+    memset(rrd_file->pvt, 0, sizeof(rrd_simple_file_t));
+    rrd_simple_file = (rrd_simple_file_t *)rrd_file->pvt;
+

 #ifdef DEBUG
     if ((rdwr & (RRD_READONLY | RRD_READWRITE)) ==
         (RRD_READONLY | RRD_READWRITE)) {
 #ifdef DEBUG
     if ((rdwr & (RRD_READONLY | RRD_READWRITE)) ==
         (RRD_READONLY | RRD_READWRITE)) {


@@ -101,47 +149,72 @@ rrd_file_t *rrd_open(
         exit(-1);
     }
 #endif
         exit(-1);
     }
 #endif

+
+#ifdef HAVE_MMAP
+    rrd_simple_file->mm_prot = PROT_READ;
+    rrd_simple_file->mm_flags = 0;
+#endif
+

     if (rdwr & RRD_READONLY) {
         flags |= O_RDONLY;
 #ifdef HAVE_MMAP
     if (rdwr & RRD_READONLY) {
         flags |= O_RDONLY;
 #ifdef HAVE_MMAP

-        mm_flags = MAP_PRIVATE;
+# if !defined(AIX)
+        rrd_simple_file->mm_flags = MAP_PRIVATE;
+# endif

 # ifdef MAP_NORESERVE
 # ifdef MAP_NORESERVE

-        mm_flags |= MAP_NORESERVE;  /* readonly, so no swap backing needed */
+        rrd_simple_file->mm_flags |= MAP_NORESERVE;  /* readonly, so no swap backing needed */

 # endif
 #endif
     } else {
         if (rdwr & RRD_READWRITE) {
 # endif
 #endif
     } else {
         if (rdwr & RRD_READWRITE) {

-            mode |= S_IWUSR;

             flags |= O_RDWR;
             flags |= O_RDWR;

-#ifdef HAVE_MMAP
-            mm_flags = MAP_SHARED;
-            mm_prot |= PROT_WRITE;
-#endif
+#ifdef HAVE_MMAP 
+            rrd_simple_file->mm_flags = MAP_SHARED; 
+            rrd_simple_file->mm_prot |= PROT_WRITE; 
+#endif 

         }
         if (rdwr & RRD_CREAT) {
             flags |= (O_CREAT | O_TRUNC);
         }
         }
         if (rdwr & RRD_CREAT) {
             flags |= (O_CREAT | O_TRUNC);
         }

+        if (rdwr & RRD_EXCL) {
+            flags |= O_EXCL;
+        }

     }
     if (rdwr & RRD_READAHEAD) {
 #ifdef MAP_POPULATE
     }
     if (rdwr & RRD_READAHEAD) {
 #ifdef MAP_POPULATE

-        mm_flags |= MAP_POPULATE;   /* populate ptes and data */
+        rrd_simple_file->mm_flags |= MAP_POPULATE;   /* populate ptes and data */

 #endif
 #if defined MAP_NONBLOCK
 #endif
 #if defined MAP_NONBLOCK

-        mm_flags |= MAP_NONBLOCK;   /* just populate ptes */
+        rrd_simple_file->mm_flags |= MAP_NONBLOCK;   /* just populate ptes */

 #endif
     }
 #if defined(_WIN32) && !defined(__CYGWIN__) && !defined(__CYGWIN32__)
     flags |= O_BINARY;
 #endif
 
 #endif
     }
 #if defined(_WIN32) && !defined(__CYGWIN__) && !defined(__CYGWIN32__)
     flags |= O_BINARY;
 #endif
 

-    if ((rrd_file->fd = open(file_name, flags, mode)) < 0) {
+    if ((rrd_simple_file->fd = open(file_name, flags, 0666)) < 0) {

         rrd_set_error("opening '%s': %s", file_name, rrd_strerror(errno));
         goto out_free;
     }
 
         rrd_set_error("opening '%s': %s", file_name, rrd_strerror(errno));
         goto out_free;
     }
 

+#ifdef HAVE_MMAP
+#ifdef HAVE_BROKEN_MS_ASYNC
+    if (rdwr & RRD_READWRITE) {    
+        /* some unices, the files mtime does not get update    
+           on msync MS_ASYNC, in order to help them,     
+           we update the the timestamp at this point.      
+           The thing happens pretty 'close' to the open    
+           call so the chances of a race should be minimal.    
+                
+           Maybe ask your vendor to fix your OS ... */    
+           utime(file_name,NULL);  
+    }
+#endif    
+#endif
+

     /* Better try to avoid seeks as much as possible. stat may be heavy but
      * many concurrent seeks are even worse.  */
     /* Better try to avoid seeks as much as possible. stat may be heavy but
      * many concurrent seeks are even worse.  */

-    if (newfile_size == 0 && ((fstat(rrd_file->fd, &statb)) < 0)) {
+    if (newfile_size == 0 && ((fstat(rrd_simple_file->fd, &statb)) < 0)) {

         rrd_set_error("fstat '%s': %s", file_name, rrd_strerror(errno));
         goto out_close;
     }
         rrd_set_error("fstat '%s': %s", file_name, rrd_strerror(errno));
         goto out_close;
     }


@@ -149,30 +222,35 @@ rrd_file_t *rrd_open(
         rrd_file->file_len = statb.st_size;
     } else {
         rrd_file->file_len = newfile_size;
         rrd_file->file_len = statb.st_size;
     } else {
         rrd_file->file_len = newfile_size;

-        lseek(rrd_file->fd, newfile_size - 1, SEEK_SET);
-        write(rrd_file->fd, "\0", 1);   /* poke */
-        lseek(rrd_file->fd, 0, SEEK_SET);
+        lseek(rrd_simple_file->fd, newfile_size - 1, SEEK_SET);
+        if ( write(rrd_simple_file->fd, "\0", 1) == -1){    /* poke */
+            rrd_set_error("write '%s': %s", file_name, rrd_strerror(errno));
+            goto out_close;
+        }
+        lseek(rrd_simple_file->fd, 0, SEEK_SET);

     }
 #ifdef HAVE_POSIX_FADVISE
     /* In general we need no read-ahead when dealing with rrd_files.
        When we stop reading, it is highly unlikely that we start up again.
        In this manner we actually save time and diskaccess (and buffer cache).
        Thanks to Dave Plonka for the Idea of using POSIX_FADV_RANDOM here. */
     }
 #ifdef HAVE_POSIX_FADVISE
     /* In general we need no read-ahead when dealing with rrd_files.
        When we stop reading, it is highly unlikely that we start up again.
        In this manner we actually save time and diskaccess (and buffer cache).
        Thanks to Dave Plonka for the Idea of using POSIX_FADV_RANDOM here. */

-    posix_fadvise(rrd_file->fd, 0, 0, POSIX_FADV_RANDOM);
+    posix_fadvise(rrd_simple_file->fd, 0, 0, POSIX_FADV_RANDOM);

 #endif
 
 /*
         if (rdwr & RRD_READWRITE)
         {
 #endif
 
 /*
         if (rdwr & RRD_READWRITE)
         {

-           if (setvbuf((rrd_file->fd),NULL,_IONBF,2)) {
+           if (setvbuf((rrd_simple_file->fd),NULL,_IONBF,2)) {

                   rrd_set_error("failed to disable the stream buffer\n");
                   return (-1);
            }
         }
 */
                   rrd_set_error("failed to disable the stream buffer\n");
                   return (-1);
            }
         }
 */

+

 #ifdef HAVE_MMAP
 #ifdef HAVE_MMAP

-    data = mmap(0, rrd_file->file_len, mm_prot, mm_flags,
-                rrd_file->fd, offset);
+    data = mmap(0, rrd_file->file_len, 
+        rrd_simple_file->mm_prot, rrd_simple_file->mm_flags,
+        rrd_simple_file->fd, offset);

 
     /* lets see if the first read worked */
     if (data == MAP_FAILED) {
 
     /* lets see if the first read worked */
     if (data == MAP_FAILED) {


@@ -180,7 +258,7 @@ rrd_file_t *rrd_open(
                       rrd_strerror(errno));
         goto out_close;
     }
                       rrd_strerror(errno));
         goto out_close;
     }

-    rrd_file->file_start = data;
+    rrd_simple_file->file_start = data;

     if (rdwr & RRD_CREAT) {
         memset(data, DNAN, newfile_size - 1);
         goto out_done;
     if (rdwr & RRD_CREAT) {
         memset(data, DNAN, newfile_size - 1);
         goto out_done;


@@ -191,12 +269,14 @@ rrd_file_t *rrd_open(
 #ifdef USE_MADVISE
     if (rdwr & RRD_COPY) {
         /* We will read everything in a moment (copying) */
 #ifdef USE_MADVISE
     if (rdwr & RRD_COPY) {
         /* We will read everything in a moment (copying) */

-        madvise(data, rrd_file->file_len, MADV_WILLNEED | MADV_SEQUENTIAL);
+        madvise(data, rrd_file->file_len, MADV_WILLNEED );
+        madvise(data, rrd_file->file_len, MADV_SEQUENTIAL );

     } else {
         /* We do not need to read anything in for the moment */
         madvise(data, rrd_file->file_len, MADV_RANDOM);
         /* the stat_head will be needed soonish, so hint accordingly */
     } else {
         /* We do not need to read anything in for the moment */
         madvise(data, rrd_file->file_len, MADV_RANDOM);
         /* the stat_head will be needed soonish, so hint accordingly */

-        madvise(data, sizeof(stat_head_t), MADV_WILLNEED | MADV_RANDOM);
+        madvise(data, sizeof(stat_head_t), MADV_WILLNEED);
+        madvise(data, sizeof(stat_head_t), MADV_RANDOM);

     }
 #endif
 
     }
 #endif
 


@@ -274,12 +354,11 @@ rrd_file_t *rrd_open(
 
     {
       unsigned long row_cnt = 0;
 
     {
       unsigned long row_cnt = 0;

-      unsigned long i;

 
 

-      for (i=0; i<rrd->stat_head->rra_cnt; i++)
-        row_cnt += rrd->rra_def[i].row_cnt;
+      for (ui=0; ui<rrd->stat_head->rra_cnt; ui++)
+        row_cnt += rrd->rra_def[ui].row_cnt;

 
 

-      off_t correct_len = rrd_file->header_len +
+      size_t  correct_len = rrd_file->header_len +

         sizeof(rrd_value_t) * row_cnt * rrd->stat_head->ds_cnt;
 
       if (correct_len > rrd_file->file_len)
         sizeof(rrd_value_t) * row_cnt * rrd->stat_head->ds_cnt;
 
       if (correct_len > rrd_file->file_len)


@@ -299,8 +378,10 @@ rrd_file_t *rrd_open(
     if (data != MAP_FAILED)
       munmap(data, rrd_file->file_len);
 #endif
     if (data != MAP_FAILED)
       munmap(data, rrd_file->file_len);
 #endif

-    close(rrd_file->fd);
+
+    close(rrd_simple_file->fd);

   out_free:
   out_free:

+    free(rrd_file->pvt);

     free(rrd_file);
     return NULL;
 }
     free(rrd_file);
     return NULL;
 }


@@ -313,9 +394,11 @@ void mincore_print(
     rrd_file_t *rrd_file,
     char *mark)
 {
     rrd_file_t *rrd_file,
     char *mark)
 {

+    rrd_simple_file_t *rrd_simple_file;
+    rrd_simple_file = (rrd_simple_file_t *)rrd_file->pvt;

 #ifdef HAVE_MMAP
     /* pretty print blocks in core */
 #ifdef HAVE_MMAP
     /* pretty print blocks in core */

-    off_t     off;
+    size_t     off;

     unsigned char *vec;
     ssize_t   _page_size = sysconf(_SC_PAGESIZE);
 
     unsigned char *vec;
     ssize_t   _page_size = sysconf(_SC_PAGESIZE);
 


@@ -324,7 +407,7 @@ void mincore_print(
     vec = malloc(off);
     if (vec != NULL) {
         memset(vec, 0, off);
     vec = malloc(off);
     if (vec != NULL) {
         memset(vec, 0, off);

-        if (mincore(rrd_file->file_start, rrd_file->file_len, vec) == 0) {
+        if (mincore(rrd_simple_file->file_start, rrd_file->file_len, vec) == 0) {

             int       prev;
             unsigned  is_in = 0, was_in = 0;
 
             int       prev;
             unsigned  is_in = 0, was_in = 0;
 


@@ -351,17 +434,55 @@ void mincore_print(
 }
 #endif                          /* defined DEBUG && DEBUG > 1 */
 
 }
 #endif                          /* defined DEBUG && DEBUG > 1 */
 

+/*
+ * get exclusive lock to whole file.
+ * lock gets removed when we close the file
+ *
+ * returns 0 on success
+ */
+int rrd_lock(
+    rrd_file_t *rrd_file)
+{
+    int       rcstat;
+    rrd_simple_file_t *rrd_simple_file;
+    rrd_simple_file = (rrd_simple_file_t *)rrd_file->pvt;
+
+    {
+#if defined(_WIN32) && !defined(__CYGWIN__) && !defined(__CYGWIN32__)
+        struct _stat st;
+
+        if (_fstat(rrd_simple_file->fd, &st) == 0) {
+            rcstat = _locking(rrd_simple_file->fd, _LK_NBLCK, st.st_size);
+        } else {
+            rcstat = -1;
+        }
+#else
+        struct flock lock;
+
+        lock.l_type = F_WRLCK;  /* exclusive write lock */
+        lock.l_len = 0; /* whole file */
+        lock.l_start = 0;   /* start of file */
+        lock.l_whence = SEEK_SET;   /* end of file */
+
+        rcstat = fcntl(rrd_simple_file->fd, F_SETLK, &lock);
+#endif
+    }
+
+    return (rcstat);
+}
+

 
 /* drop cache except for the header and the active pages */
 void rrd_dontneed(
     rrd_file_t *rrd_file,
     rrd_t *rrd)
 {
 
 /* drop cache except for the header and the active pages */
 void rrd_dontneed(
     rrd_file_t *rrd_file,
     rrd_t *rrd)
 {

+    rrd_simple_file_t *rrd_simple_file = (rrd_simple_file_t *)rrd_file->pvt;

 #if defined USE_MADVISE || defined HAVE_POSIX_FADVISE
 #if defined USE_MADVISE || defined HAVE_POSIX_FADVISE

-    off_t dontneed_start;
-    off_t rra_start;
-    off_t active_block;
-    unsigned long i;
+    size_t dontneed_start;
+    size_t rra_start;
+    size_t active_block;
+    size_t i;

     ssize_t   _page_size = sysconf(_SC_PAGESIZE);
 
     if (rrd_file == NULL) {
     ssize_t   _page_size = sysconf(_SC_PAGESIZE);
 
     if (rrd_file == NULL) {


@@ -385,12 +506,12 @@ void rrd_dontneed(
                        * rrd->stat_head->ds_cnt * sizeof(rrd_value_t));
         if (active_block > dontneed_start) {
 #ifdef USE_MADVISE
                        * rrd->stat_head->ds_cnt * sizeof(rrd_value_t));
         if (active_block > dontneed_start) {
 #ifdef USE_MADVISE

-            madvise(rrd_file->file_start + dontneed_start,
+            madvise(rrd_simple_file->file_start + dontneed_start,

                     active_block - dontneed_start - 1, MADV_DONTNEED);
 #endif
 /* in linux at least only fadvise DONTNEED seems to purge pages from cache */
 #ifdef HAVE_POSIX_FADVISE
                     active_block - dontneed_start - 1, MADV_DONTNEED);
 #endif
 /* in linux at least only fadvise DONTNEED seems to purge pages from cache */
 #ifdef HAVE_POSIX_FADVISE

-            posix_fadvise(rrd_file->fd, dontneed_start,
+            posix_fadvise(rrd_simple_file->fd, dontneed_start,

                           active_block - dontneed_start - 1,
                           POSIX_FADV_DONTNEED);
 #endif
                           active_block - dontneed_start - 1,
                           POSIX_FADV_DONTNEED);
 #endif


@@ -410,11 +531,11 @@ void rrd_dontneed(
 
     if (dontneed_start < rrd_file->file_len) {
 #ifdef USE_MADVISE
 
     if (dontneed_start < rrd_file->file_len) {
 #ifdef USE_MADVISE

-           madvise(rrd_file->file_start + dontneed_start,
+           madvise(rrd_simple_file->file_start + dontneed_start,

                    rrd_file->file_len - dontneed_start, MADV_DONTNEED);
 #endif
 #ifdef HAVE_POSIX_FADVISE
                    rrd_file->file_len - dontneed_start, MADV_DONTNEED);
 #endif
 #ifdef HAVE_POSIX_FADVISE

-           posix_fadvise(rrd_file->fd, dontneed_start,
+           posix_fadvise(rrd_simple_file->fd, dontneed_start,

                          rrd_file->file_len - dontneed_start,
                          POSIX_FADV_DONTNEED);
 #endif
                          rrd_file->file_len - dontneed_start,
                          POSIX_FADV_DONTNEED);
 #endif


@@ -423,7 +544,7 @@ void rrd_dontneed(
 #if defined DEBUG && DEBUG > 1
     mincore_print(rrd_file, "after");
 #endif
 #if defined DEBUG && DEBUG > 1
     mincore_print(rrd_file, "after");
 #endif

-#endif                          /* without madvise and posix_fadvise ist does not make much sense todo anything */
+#endif                          /* without madvise and posix_fadvise it does not make much sense todo anything */

 }
 
 
 }
 
 


@@ -433,19 +554,22 @@ void rrd_dontneed(
 int rrd_close(
     rrd_file_t *rrd_file)
 {
 int rrd_close(
     rrd_file_t *rrd_file)
 {

+    rrd_simple_file_t *rrd_simple_file;
+    rrd_simple_file = (rrd_simple_file_t *)rrd_file->pvt;

     int       ret;
 
 #ifdef HAVE_MMAP
     int       ret;
 
 #ifdef HAVE_MMAP

-    ret = msync(rrd_file->file_start, rrd_file->file_len, MS_ASYNC);
+    ret = msync(rrd_simple_file->file_start, rrd_file->file_len, MS_ASYNC);

     if (ret != 0)
         rrd_set_error("msync rrd_file: %s", rrd_strerror(errno));
     if (ret != 0)
         rrd_set_error("msync rrd_file: %s", rrd_strerror(errno));

-    ret = munmap(rrd_file->file_start, rrd_file->file_len);
+    ret = munmap(rrd_simple_file->file_start, rrd_file->file_len);

     if (ret != 0)
         rrd_set_error("munmap rrd_file: %s", rrd_strerror(errno));
 #endif
     if (ret != 0)
         rrd_set_error("munmap rrd_file: %s", rrd_strerror(errno));
 #endif

-    ret = close(rrd_file->fd);
+    ret = close(rrd_simple_file->fd);

     if (ret != 0)
         rrd_set_error("closing file: %s", rrd_strerror(errno));
     if (ret != 0)
         rrd_set_error("closing file: %s", rrd_strerror(errno));

+    free(rrd_file->pvt);

     free(rrd_file);
     rrd_file = NULL;
     return ret;
     free(rrd_file);
     rrd_file = NULL;
     return ret;


@@ -460,6 +584,8 @@ off_t rrd_seek(
     int whence)
 {
     off_t     ret = 0;
     int whence)
 {
     off_t     ret = 0;

+    rrd_simple_file_t *rrd_simple_file;
+    rrd_simple_file = (rrd_simple_file_t *)rrd_file->pvt;

 
 #ifdef HAVE_MMAP
     if (whence == SEEK_SET)
 
 #ifdef HAVE_MMAP
     if (whence == SEEK_SET)


@@ -469,7 +595,7 @@ off_t rrd_seek(
     else if (whence == SEEK_END)
         rrd_file->pos = rrd_file->file_len + off;
 #else
     else if (whence == SEEK_END)
         rrd_file->pos = rrd_file->file_len + off;
 #else

-    ret = lseek(rrd_file->fd, off, whence);
+    ret = lseek(rrd_simple_file->fd, off, whence);

     if (ret < 0)
         rrd_set_error("lseek: %s", rrd_strerror(errno));
     rrd_file->pos = ret;
     if (ret < 0)
         rrd_set_error("lseek: %s", rrd_strerror(errno));
     rrd_file->pos = ret;


@@ -496,6 +622,7 @@ ssize_t rrd_read(
     void *buf,
     size_t count)
 {
     void *buf,
     size_t count)
 {

+    rrd_simple_file_t *rrd_simple_file = (rrd_simple_file_t *)rrd_file->pvt;

 #ifdef HAVE_MMAP
     size_t    _cnt = count;
     ssize_t   _surplus;
 #ifdef HAVE_MMAP
     size_t    _cnt = count;
     ssize_t   _surplus;


@@ -510,14 +637,14 @@ ssize_t rrd_read(
     }
     if (_cnt == 0)
         return 0;       /* EOF */
     }
     if (_cnt == 0)
         return 0;       /* EOF */

-    buf = memcpy(buf, rrd_file->file_start + rrd_file->pos, _cnt);
+    buf = memcpy(buf, rrd_simple_file->file_start + rrd_file->pos, _cnt);

 
     rrd_file->pos += _cnt;  /* mimmic read() semantics */
     return _cnt;
 #else
     ssize_t   ret;
 
 
     rrd_file->pos += _cnt;  /* mimmic read() semantics */
     return _cnt;
 #else
     ssize_t   ret;
 

-    ret = read(rrd_file->fd, buf, count);
+    ret = read(rrd_simple_file->fd, buf, count);

     if (ret > 0)
         rrd_file->pos += ret;   /* mimmic read() semantics */
     return ret;
     if (ret > 0)
         rrd_file->pos += ret;   /* mimmic read() semantics */
     return ret;


@@ -526,7 +653,7 @@ ssize_t rrd_read(
 
 
 /* Write count bytes from buffer buf to the current position
 
 
 /* Write count bytes from buffer buf to the current position

- * rrd_file->pos of rrd_file->fd.
+ * rrd_file->pos of rrd_simple_file->fd.

  * Returns the number of bytes written or <0 on error.  */
 
 ssize_t rrd_write(
  * Returns the number of bytes written or <0 on error.  */
 
 ssize_t rrd_write(


@@ -534,16 +661,24 @@ ssize_t rrd_write(
     const void *buf,
     size_t count)
 {
     const void *buf,
     size_t count)
 {

+    rrd_simple_file_t *rrd_simple_file = (rrd_simple_file_t *)rrd_file->pvt;

 #ifdef HAVE_MMAP
 #ifdef HAVE_MMAP

+    size_t old_size = rrd_file->file_len;

     if (count == 0)
         return 0;
     if (buf == NULL)
         return -1;      /* EINVAL */
     if (count == 0)
         return 0;
     if (buf == NULL)
         return -1;      /* EINVAL */

-    memcpy(rrd_file->file_start + rrd_file->pos, buf, count);
+    
+    if((rrd_file->pos + count) > old_size)
+    {
+        rrd_set_error("attempting to write beyond end of file");
+        return -1;
+    }
+    memcpy(rrd_simple_file->file_start + rrd_file->pos, buf, count);

     rrd_file->pos += count;
     return count;       /* mimmic write() semantics */
 #else
     rrd_file->pos += count;
     return count;       /* mimmic write() semantics */
 #else

-    ssize_t   _sz = write(rrd_file->fd, buf, count);
+    ssize_t   _sz = write(rrd_simple_file->fd, buf, count);

 
     if (_sz > 0)
         rrd_file->pos += _sz;
 
     if (_sz > 0)
         rrd_file->pos += _sz;


@@ -552,18 +687,13 @@ ssize_t rrd_write(
 }
 
 
 }
 
 

-/* flush all data pending to be written to FD.  */
-
+/* this is a leftover from the old days, it serves no purpose
+   and is therefore turned into a no-op */

 void rrd_flush(
 void rrd_flush(

-    rrd_file_t *rrd_file)
+    rrd_file_t UNUSED(*rrd_file))

 {
 {

-    if (fdatasync(rrd_file->fd) != 0) {
-        rrd_set_error("flushing fd %d: %s", rrd_file->fd,
-                      rrd_strerror(errno));
-    }

 }
 
 }
 

-

 /* Initialize RRD header.  */
 
 void rrd_init(
 /* Initialize RRD header.  */
 
 void rrd_init(


@@ -615,3 +745,32 @@ void rrd_freemem(
 {
     free(mem);
 }
 {
     free(mem);
 }

+
+/*
+ * rra_update informs us about the RRAs being updated
+ * The low level storage API may use this information for
+ * aligning RRAs within stripes, or other performance enhancements
+ */
+void rrd_notify_row(
+    rrd_file_t UNUSED(*rrd_file),
+    int UNUSED(rra_idx),
+    unsigned long UNUSED(rra_row),
+    time_t UNUSED(rra_time))
+{
+}
+
+/*
+ * This function is called when creating a new RRD
+ * The storage implementation can use this opportunity to select
+ * a sensible starting row within the file.
+ * The default implementation is random, to ensure that all RRAs
+ * don't change to a new disk block at the same time
+ */
+unsigned long rrd_select_initial_row(
+    rrd_file_t UNUSED(*rrd_file),
+    int UNUSED(rra_idx),
+    rra_def_t *rra
+    )
+{
+    return rrd_random() % rra->row_cnt;
+}