+
+/* Close a reference to an rrd_file. */
+
+int rrd_close(
+ rrd_file_t *rrd_file)
+{
+ int ret;
+
+#if defined HAVE_MMAP || defined DEBUG
+ ssize_t _page_size = sysconf(_SC_PAGESIZE);
+#endif
+#if defined DEBUG && DEBUG > 1
+ /* pretty print blocks in core */
+ off_t off;
+ unsigned char *vec;
+
+ off = rrd_file->file_len +
+ ((rrd_file->file_len + _page_size - 1) / _page_size);
+ vec = malloc(off);
+ if (vec != NULL) {
+ memset(vec, 0, off);
+ if (mincore(rrd_file->file_start, rrd_file->file_len, vec) == 0) {
+ int prev;
+ unsigned is_in = 0, was_in = 0;
+
+ for (off = 0, prev = 0; off < rrd_file->file_len; ++off) {
+ is_in = vec[off] & 1; /* if lsb set then is core resident */
+ if (off == 0)
+ was_in = is_in;
+ if (was_in != is_in) {
+ fprintf(stderr, "%sin core: %p len %ld\n",
+ was_in ? "" : "not ", vec + prev, off - prev);
+ was_in = is_in;
+ prev = off;
+ }
+ }
+ fprintf(stderr,
+ "%sin core: %p len %ld\n",
+ was_in ? "" : "not ", vec + prev, off - prev);
+ } else
+ fprintf(stderr, "mincore: %s", rrd_strerror(errno));
+ }
+#endif /* DEBUG */
+
+#ifdef USE_MADVISE
+# ifdef ONE_PAGE
+ /* Keep headers around, round up to next page boundary. */
+ ret =
+ PAGE_ALIGN(rrd_file->header_len % _page_size + rrd_file->header_len);
+ if (rrd_file->file_len > ret)
+ _madvise(rrd_file->file_start + ret,
+ rrd_file->file_len - ret, MADV_DONTNEED);
+# else
+ /* ignoring errors from RRDs that are smaller then the file_len+rounding */
+ _madvise(rrd_file->file_start + PAGE_ALIGN_DOWN(rrd_file->header_len),
+ rrd_file->file_len - PAGE_ALIGN(rrd_file->header_len),
+ MADV_DONTNEED);
+# endif
+#endif
+#ifdef HAVE_MMAP
+ ret = munmap(rrd_file->file_start, rrd_file->file_len);
+ if (ret != 0)
+ rrd_set_error("munmap rrd_file: %s", rrd_strerror(errno));
+#endif
+ ret = close(rrd_file->fd);
+ if (ret != 0)
+ rrd_set_error("closing file: %s", rrd_strerror(errno));
+ free(rrd_file);
+ rrd_file = NULL;
+ return ret;
+}
+
+
+/* Set position of rrd_file. */
+
+off_t rrd_seek(
+ rrd_file_t *rrd_file,
+ off_t off,
+ int whence)
+{
+ off_t ret = 0;
+
+#ifdef HAVE_MMAP
+ if (whence == SEEK_SET)
+ rrd_file->pos = off;
+ else if (whence == SEEK_CUR)
+ rrd_file->pos += off;
+ else if (whence == SEEK_END)
+ rrd_file->pos = rrd_file->file_len + off;
+#else
+ ret = lseek(rrd_file->fd, off, whence);
+ if (ret < 0)
+ 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
+}
+
+
+/* Get current position in rrd_file. */
+
+inline off_t rrd_tell(
+ rrd_file_t *rrd_file)
+{
+ return 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(
+ rrd_file_t *rrd_file,
+ void *buf,
+ size_t count)
+{
+#ifdef HAVE_MMAP
+ size_t _cnt = count;
+ ssize_t _surplus = rrd_file->pos + _cnt - rrd_file->file_len;
+
+ if (_surplus > 0) { /* short read */
+ _cnt -= _surplus;
+ }
+ if (_cnt == 0)
+ return 0; /* EOF */
+ buf = memcpy(buf, rrd_file->file_start + rrd_file->pos, _cnt);
+
+ rrd_file->pos += _cnt; /* mimmic read() semantics */
+ return _cnt;
+#else
+ ssize_t ret;
+
+ ret = read(rrd_file->fd, buf, count);
+ if (ret > 0)
+ rrd_file->pos += ret; /* mimmic read() semantics */
+ return ret;
+#endif
+}
+
+
+/* write count bytes from buffer buf to the current position
+ * rrd_file->pos of rrd_file->fd.
+ * Returns the number of bytes written. */
+
+inline ssize_t rrd_write(
+ rrd_file_t *rrd_file,
+ const void *buf,
+ size_t count)
+{
+#ifdef HAVE_MMAP
+ memcpy(rrd_file->file_start + rrd_file->pos, buf, count);
+ rrd_file->pos += count;
+ return count; /* mimmic write() semantics */
+#else
+ ssize_t _sz = write(rrd_file->fd, buf, count);
+
+ if (_sz > 0)
+ rrd_file->pos += _sz;
+ return _sz;
+#endif
+}
+
+
+/* flush all data pending to be written to FD. */
+
+inline void rrd_flush(
+ rrd_file_t *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(
+ rrd_t *rrd)