fixed 2. x-grid example ... since the lable is valid for the whole day, it must be...

[rrdtool.git] / src / rrd_open.c

diff --git a/src/rrd_open.c b/src/rrd_open.c
index 0774bce..4acaa8f 100644 (file)
--- a/src/rrd_open.c
+++ b/src/rrd_open.c
@@ -140,11 +140,7 @@ rrd_file_t *rrd_open(
        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. */
-    if (0 != posix_fadvise(rrd_file->fd, 0, 0, POSIX_FADV_RANDOM)) {
-        rrd_set_error("setting POSIX_FADV_RANDOM on '%s': %s", file_name,
-                      rrd_strerror(errno));
-        goto out_close;
-    }
+    posix_fadvise(rrd_file->fd, 0, 0, POSIX_FADV_RANDOM);
 #endif
 
 /*
@@ -272,7 +268,8 @@ rrd_file_t *rrd_open(
 }
 
 
-/* Close a reference to an rrd_file.  */
+#if defined DEBUG && DEBUG > 1
+/* Print list of in-core pages of a the current rrd_file.  */
 static
 void mincore_print(
     rrd_file_t *rrd_file,
@@ -314,6 +311,7 @@ void mincore_print(
     fprintf(stderr, "sorry mincore only works with mmap");
 #endif
 }
+#endif                          /* defined DEBUG && DEBUG > 1 */
 
 
 /* drop cache except for the header and the active pages */
@@ -352,7 +350,8 @@ void rrd_dontneed(
 #endif
         }
         dontneed_start = active_block;
-        /* do not relase 'hot' block if update for this RAA will occure within 10 minutes */
+        /* do not release 'hot' block if update for this RAA will occur
+         * within 10 minutes */
         if (rrd->stat_head->pdp_step * rrd->rra_def[i].pdp_cnt -
             rrd->live_head->last_up % (rrd->stat_head->pdp_step *
                                        rrd->rra_def[i].pdp_cnt) < 10 * 60) {
@@ -381,6 +380,9 @@ int rrd_close(
     int       ret;
 
 #ifdef HAVE_MMAP
+    ret = msync(rrd_file->file_start, rrd_file->file_len, MS_ASYNC);
+    if (ret != 0)
+        rrd_set_error("msync rrd_file: %s", rrd_strerror(errno));
     ret = munmap(rrd_file->file_start, rrd_file->file_len);
     if (ret != 0)
         rrd_set_error("munmap rrd_file: %s", rrd_strerror(errno));
@@ -416,8 +418,8 @@ off_t rrd_seek(
         rrd_set_error("lseek: %s", rrd_strerror(errno));
     rrd_file->pos = ret;
 #endif
-//XXX: mimic fseek, which returns 0 upon success
-    return ret == -1;   //XXX: or just ret to mimic lseek
+    /* mimic fseek, which returns 0 upon success */
+    return ret < 0;     //XXX: or just ret to mimic lseek
 }
 
 
@@ -430,7 +432,7 @@ inline off_t rrd_tell(
 }
 
 
-/* read count bytes into buffer buf, starting at rrd_file->pos.
+/* Read count bytes into buffer buf, starting at rrd_file->pos.
  * Returns the number of bytes read or <0 on error.  */
 
 inline ssize_t rrd_read(
@@ -440,8 +442,13 @@ inline ssize_t rrd_read(
 {
 #ifdef HAVE_MMAP
     size_t    _cnt = count;
-    ssize_t   _surplus = rrd_file->pos + _cnt - rrd_file->file_len;
+    ssize_t   _surplus;
 
+    if (rrd_file->pos > rrd_file->file_len || _cnt == 0)    /* EOF */
+        return 0;
+    if (buf == NULL)
+        return -1;      /* EINVAL */
+    _surplus = rrd_file->pos + _cnt - rrd_file->file_len;
     if (_surplus > 0) { /* short read */
         _cnt -= _surplus;
     }
@@ -462,9 +469,9 @@ inline 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.
- * Returns the number of bytes written.  */
+ * Returns the number of bytes written or <0 on error.  */
 
 inline ssize_t rrd_write(
     rrd_file_t *rrd_file,
@@ -472,6 +479,10 @@ inline ssize_t rrd_write(
     size_t count)
 {
 #ifdef HAVE_MMAP
+    if (count == 0)
+        return 0;
+    if (buf == NULL)
+        return -1;      /* EINVAL */
     memcpy(rrd_file->file_start + rrd_file->pos, buf, count);
     rrd_file->pos += count;
     return count;       /* mimmic write() semantics */