/*
- * Sherlock Library -- Mapping of File Parts
+ * UCW Library -- Mapping of File Parts
*
- * (c) 2003 Martin Mares <mj@ucw.cz>
- * (c) 2003 Robert Spalek <robert@ucw.cz>
+ * (c) 2003--2006 Martin Mares <mj@ucw.cz>
+ * (c) 2003--2005 Robert Spalek <robert@ucw.cz>
*
* This software may be freely distributed and used according to the terms
* of the GNU Lesser General Public License.
#include "lib/lib.h"
#include "lib/lfs.h"
+#include "lib/partmap.h"
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/mman.h>
+#include <sys/user.h>
-struct partmap {
- int fd;
- sh_off_t file_size;
- sh_off_t start_off, end_off;
- byte *start_map;
- int writeable;
-};
-
+#ifdef CONFIG_PARTMAP_IS_MMAP
+#define PARTMAP_WINDOW ~(size_t)0
+#else
#ifdef TEST
#define PARTMAP_WINDOW 4096
#else
#define PARTMAP_WINDOW 16777216
#endif
-
-static uns page_size;
+#endif
struct partmap *
partmap_open(byte *name, int writeable)
{
- if (!page_size)
- page_size = getpagesize();
-
struct partmap *p = xmalloc_zero(sizeof(struct partmap));
p->fd = sh_open(name, writeable ? O_RDWR : O_RDONLY);
if ((p->file_size = sh_seek(p->fd, 0, SEEK_END)) < 0)
die("lseek(%s): %m", name);
p->writeable = writeable;
+#ifdef CONFIG_PARTMAP_IS_MMAP
+ partmap_load(p, 0, p->file_size);
+#endif
return p;
}
xfree(p);
}
-void *
-partmap_map(struct partmap *p, sh_off_t start, uns size)
+void
+partmap_load(struct partmap *p, sh_off_t start, uns size)
{
- if (!p->start_map || start < p->start_off || start+size > p->end_off)
- {
- if (p->start_map)
- munmap(p->start_map, p->end_off - p->start_off);
- uns win = PARTMAP_WINDOW;
- ASSERT(win >= size);
- sh_off_t end = start + size;
- start = start/page_size * page_size;
- if (start+win > p->file_size)
- win = p->file_size - start;
- if (start+win < end)
- die("cannot mmap, the window is too small");
- p->start_map = sh_mmap(NULL, win, p->writeable ? (PROT_READ | PROT_WRITE) : PROT_READ, MAP_SHARED, p->fd, start);
- if (p->start_map == MAP_FAILED)
- die("mmap failed at position %Ld: %m", (long long)start);
- p->start_off = start;
- p->end_off = start+win;
- }
- return p->start_map + (start - p->start_off);
+ if (p->start_map)
+ munmap(p->start_map, p->end_off - p->start_off);
+ sh_off_t end = start + size;
+ sh_off_t win_start = start/PAGE_SIZE * PAGE_SIZE;
+ size_t win_len = PARTMAP_WINDOW;
+ if ((sh_off_t) (win_start+win_len) > p->file_size)
+ win_len = ALIGN(p->file_size - win_start, PAGE_SIZE);
+ if ((sh_off_t) (win_start+win_len) < end)
+ die("partmap_map: Window is too small for mapping %d bytes", size);
+ p->start_map = sh_mmap(NULL, win_len, p->writeable ? (PROT_READ | PROT_WRITE) : PROT_READ, MAP_SHARED, p->fd, win_start);
+ if (p->start_map == MAP_FAILED)
+ die("mmap failed at position %Ld: %m", (long long)win_start);
+ p->start_off = win_start;
+ p->end_off = win_start+win_len;
+ madvise(p->start_map, win_len, MADV_SEQUENTIAL);
}
#ifdef TEST