* this preserves principle of least surprise when dealing with files that

[rrdtool.git] / src / rrd_open.c

diff --git a/src/rrd_open.c b/src/rrd_open.c
index 2796506..86d608c 100644 (file)
--- a/src/rrd_open.c
+++ b/src/rrd_open.c
@@ -79,13 +79,14 @@ rrd_file_t *rrd_open(
     rrd_file_t *rrd_file = NULL;
     off_t     newfile_size = 0;
 
-    if (rdwr & RRD_CREAT) {
+    if ((rdwr & RRD_CREAT) && (rdwr & RRD_CREAT_SETSIZE)) {
         /* 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);
     }
-    rrd_init(rrd);
+    if(!(rdwr & RRD_CREAT))
+        rrd_init(rrd);
     rrd_file = malloc(sizeof(rrd_file_t));
     if (rrd_file == NULL) {
         rrd_set_error("allocating rrd_file descriptor for '%s'", file_name);
@@ -170,7 +171,13 @@ rrd_file_t *rrd_open(
            }
         }
 */
+
 #ifdef HAVE_MMAP
+    if(rrd_file->file_len == 0 && (rdwr & RRD_CREAT))
+    {
+        rrd_file->file_start = NULL;
+        goto out_done;
+    }
     data = mmap(0, rrd_file->file_len, mm_prot, mm_flags,
                 rrd_file->fd, offset);
 
@@ -364,6 +371,13 @@ void rrd_dontneed(
     unsigned long i;
     ssize_t   _page_size = sysconf(_SC_PAGESIZE);
 
+    if (rrd_file == NULL) {
+#if defined DEBUG && DEBUG
+           fprintf (stderr, "rrd_dontneed: Argument 'rrd_file' is NULL.\n");
+#endif
+           return;
+    }
+
 #if defined DEBUG && DEBUG > 1
     mincore_print(rrd_file, "before");
 #endif
@@ -528,10 +542,36 @@ ssize_t rrd_write(
     size_t count)
 {
 #ifdef HAVE_MMAP
+    /* These flags are used if creating a new RRD */
+    int       mm_prot = PROT_READ | PROT_WRITE, mm_flags = MAP_SHARED;
+    int old_size = rrd_file->file_len;
+    int new_size = rrd_file->file_len;
     if (count == 0)
         return 0;
     if (buf == NULL)
         return -1;      /* EINVAL */
+    
+    if((rrd_file->pos + count) > old_size)
+    {
+        new_size = rrd_file->pos + count; 
+        rrd_file->file_len = new_size;
+        lseek(rrd_file->fd, new_size - 1, SEEK_SET);
+        write(rrd_file->fd, "\0", 1);   /* poke */
+        lseek(rrd_file->fd, 0, SEEK_SET);
+        if(rrd_file->file_start == NULL)
+        {
+            rrd_file->file_start = mmap(0, new_size, mm_prot, mm_flags,
+                rrd_file->fd, 0);
+        }
+        else
+            rrd_file->file_start = mremap(rrd_file->file_start, old_size, new_size, MREMAP_MAYMOVE); 
+
+        if (rrd_file->file_start == MAP_FAILED) {
+            rrd_set_error("m(re)maping file : %s", 
+                      rrd_strerror(errno));
+            return -1;
+        }
+    }
     memcpy(rrd_file->file_start + rrd_file->pos, buf, count);
     rrd_file->pos += count;
     return count;       /* mimmic write() semantics */