- encapsulate fd and mmap related variables within a private data

structure
- rrd_file_t keeps a pointer to the private data structure of type
void*, so that other block storage implementations can store their
internal data with rrd_file_t
-- Daniel.Pocock

git-svn-id: svn://svn.oetiker.ch/rrdtool/trunk@1619 a5681a0c-68f1-0310-ab6d-d61299d08faa

diff --git a/program/src/rrd.h b/program/src/rrd.h
index 34ce78e8e4eb924b9e3018c4c74e4d10e1923efe..3e0c871a56459b7cdf9b169ddab0615679e7178e 100644 (file)
--- a/program/src/rrd.h
+++ b/program/src/rrd.h
@@ -79,16 +79,21 @@ extern    "C" {
 
 /* information about an rrd file */
     typedef struct rrd_file_t {
-        int       fd;   /* file descriptor if this rrd file */
-        char     *file_start;   /* start address of an open rrd file */
         off_t     header_len;   /* length of the header of this rrd file */
         off_t     file_len; /* total size of the rrd file */
         off_t     pos;  /* current pos in file */
+        void      *pvt;
+    } rrd_file_t;
+
+/* information used for the conventional file access methods */
+    typedef struct rrd_simple_file_t {
+        int       fd;  /* file descriptor of this rrd file */
 #ifdef HAVE_MMAP
+        char     *file_start;   /* start address of an open rrd file */
         int       mm_prot;
         int       mm_flags;
 #endif
-    } rrd_file_t;
+    } rrd_simple_file_t;
 
 /* rrd info interface */
     typedef struct rrd_blob_t {

diff --git a/program/src/rrd_open.c b/program/src/rrd_open.c
index 8ae5fd8b61143853d2010d33c80de70b44b7e39a..101e3c3d03a27e82770d67d9db6b0f5f53138ad4 100644 (file)
--- a/program/src/rrd_open.c
+++ b/program/src/rrd_open.c
@@ -38,7 +38,7 @@
                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; \
@@ -81,6 +81,7 @@ rrd_file_t *rrd_open(
     off_t     offset = 0;
     struct stat statb;
     rrd_file_t *rrd_file = NULL;
+    rrd_simple_file_t *rrd_simple_file = NULL;
     off_t     newfile_size = 0;
     off_t header_len, value_cnt, data_len;
 
@@ -113,6 +114,14 @@ rrd_file_t *rrd_open(
     }
     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)) {
@@ -123,16 +132,16 @@ rrd_file_t *rrd_open(
 #endif
 
 #ifdef HAVE_MMAP
-    rrd_file->mm_prot = PROT_READ;
-    rrd_file->mm_flags = 0;
+    rrd_simple_file->mm_prot = PROT_READ;
+    rrd_simple_file->mm_flags = 0;
 #endif
 
     if (rdwr & RRD_READONLY) {
         flags |= O_RDONLY;
 #ifdef HAVE_MMAP
-        rrd_file->mm_flags = MAP_PRIVATE;
+        rrd_simple_file->mm_flags = MAP_PRIVATE;
 # ifdef MAP_NORESERVE
-        rrd_file->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 {
@@ -140,8 +149,8 @@ rrd_file_t *rrd_open(
             mode |= S_IWUSR;
             flags |= O_RDWR;
 #ifdef HAVE_MMAP
-            rrd_file->mm_flags = MAP_SHARED;
-            rrd_file->mm_prot |= PROT_WRITE;
+            rrd_simple_file->mm_flags = MAP_SHARED;
+            rrd_simple_file->mm_prot |= PROT_WRITE;
 #endif
         }
         if (rdwr & RRD_CREAT) {
@@ -150,24 +159,24 @@ rrd_file_t *rrd_open(
     }
     if (rdwr & RRD_READAHEAD) {
 #ifdef MAP_POPULATE
-        rrd_file->mm_flags |= MAP_POPULATE;   /* populate ptes and data */
+        rrd_simple_file->mm_flags |= MAP_POPULATE;   /* populate ptes and data */
 #endif
 #if defined MAP_NONBLOCK
-        rrd_file->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
 
-    if ((rrd_file->fd = open(file_name, flags, mode)) < 0) {
+    if ((rrd_simple_file->fd = open(file_name, flags, mode)) < 0) {
         rrd_set_error("opening '%s': %s", file_name, rrd_strerror(errno));
         goto out_free;
     }
 
     /* 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;
     }
@@ -175,22 +184,22 @@ rrd_file_t *rrd_open(
         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);
+        write(rrd_simple_file->fd, "\0", 1);   /* poke */
+        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. */
-    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)
         {
-           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);
            }
@@ -198,8 +207,9 @@ rrd_file_t *rrd_open(
 */
 
 #ifdef HAVE_MMAP
-    data = mmap(0, rrd_file->file_len, rrd_file->mm_prot, rrd_file->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) {
@@ -207,7 +217,7 @@ rrd_file_t *rrd_open(
                       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;
@@ -326,8 +336,9 @@ rrd_file_t *rrd_open(
     if (data != MAP_FAILED)
       munmap(data, rrd_file->file_len);
 #endif
-    close(rrd_file->fd);
+    close(rrd_simple_file->fd);
   out_free:
+    free(rrd_file->pvt);
     free(rrd_file);
     return NULL;
 }
@@ -340,6 +351,8 @@ void mincore_print(
     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 */
     off_t     off;
@@ -351,7 +364,7 @@ void mincore_print(
     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;
 
@@ -385,16 +398,18 @@ void mincore_print(
  * returns 0 on success
  */
 int rrd_lock(
-    rrd_file_t *file)
+    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(file->fd, &st) == 0) {
-            rcstat = _locking(file->fd, _LK_NBLCK, st.st_size);
+        if (_fstat(rrd_simple_file->fd, &st) == 0) {
+            rcstat = _locking(rrd_simple_file->fd, _LK_NBLCK, st.st_size);
         } else {
             rcstat = -1;
         }
@@ -406,7 +421,7 @@ int rrd_lock(
         lock.l_start = 0;   /* start of file */
         lock.l_whence = SEEK_SET;   /* end of file */
 
-        rcstat = fcntl(file->fd, F_SETLK, &lock);
+        rcstat = fcntl(rrd_simple_file->fd, F_SETLK, &lock);
 #endif
     }
 
@@ -419,6 +434,7 @@ 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
     off_t dontneed_start;
     off_t rra_start;
@@ -447,12 +463,12 @@ void rrd_dontneed(
                        * 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
-            posix_fadvise(rrd_file->fd, dontneed_start,
+            posix_fadvise(rrd_simple_file->fd, dontneed_start,
                           active_block - dontneed_start - 1,
                           POSIX_FADV_DONTNEED);
 #endif
@@ -472,11 +488,11 @@ void rrd_dontneed(
 
     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
-           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
@@ -495,19 +511,22 @@ void rrd_dontneed(
 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
-    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));
-    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
-    ret = close(rrd_file->fd);
+    ret = close(rrd_simple_file->fd);
     if (ret != 0)
         rrd_set_error("closing file: %s", rrd_strerror(errno));
+    free(rrd_file->pvt);
     free(rrd_file);
     rrd_file = NULL;
     return ret;
@@ -522,6 +541,8 @@ off_t rrd_seek(
     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)
@@ -531,7 +552,7 @@ off_t rrd_seek(
     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;
@@ -558,6 +579,7 @@ ssize_t rrd_read(
     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;
@@ -572,14 +594,14 @@ ssize_t rrd_read(
     }
     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;
 
-    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;
@@ -588,7 +610,7 @@ ssize_t rrd_read(
 
 
 /* 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(
@@ -596,6 +618,7 @@ ssize_t rrd_write(
     const void *buf,
     size_t count)
 {
+    rrd_simple_file_t *rrd_simple_file = (rrd_simple_file_t *)rrd_file->pvt;
 #ifdef HAVE_MMAP
     int old_size = rrd_file->file_len;
     if (count == 0)
@@ -608,11 +631,11 @@ ssize_t rrd_write(
         rrd_set_error("attempting to write beyond end of file");
         return -1;
     }
-    memcpy(rrd_file->file_start + rrd_file->pos, buf, count);
+    memcpy(rrd_simple_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);
+    ssize_t   _sz = write(rrd_simple_file->fd, buf, count);
 
     if (_sz > 0)
         rrd_file->pos += _sz;
@@ -626,8 +649,10 @@ ssize_t rrd_write(
 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_simple_file_t *rrd_simple_file;
+    rrd_simple_file = (rrd_simple_file_t *)rrd_file->pvt;
+    if (fdatasync(rrd_simple_file->fd) != 0) {
+        rrd_set_error("flushing fd %d: %s", rrd_simple_file->fd,
                       rrd_strerror(errno));
     }
 }