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authorAndrew Tridgell <tridge@samba.org>2001-05-15 14:53:06 +0000
committerAndrew Tridgell <tridge@samba.org>2001-05-15 14:53:06 +0000
commite863446e79350b640e7559e5e5e459184567436e (patch)
tree6cd658dc159f804243400b42c59e791ce17bec84 /source3
parentad87e772379b931440a6aab4dd0385a293de777b (diff)
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make sure that when a tdb expands we fill the expanded area, otherwise ENOSPC could be very bad
(This used to be commit b94cfb6843dc7fc985917395d3e0d953501b9197)
Diffstat (limited to 'source3')
-rw-r--r--source3/tdb/tdb.c35
1 files changed, 29 insertions, 6 deletions
diff --git a/source3/tdb/tdb.c b/source3/tdb/tdb.c
index 5fcea52d5e..2c2d78f719 100644
--- a/source3/tdb/tdb.c
+++ b/source3/tdb/tdb.c
@@ -302,7 +302,7 @@ static int update_tailer(TDB_CONTEXT *tdb, tdb_off offset,
void tdb_printfreelist(TDB_CONTEXT *tdb)
{
long total_free = 0;
- tdb_off offset, rec_ptr, last_ptr;
+ tdb_off offset, rec_ptr, last_ptr;
struct list_struct rec, lastrec, newrec;
tdb_lock(tdb, -1, F_WRLCK);
@@ -421,13 +421,39 @@ static int tdb_free(TDB_CONTEXT *tdb, tdb_off offset, struct list_struct *rec)
return -1;
}
+
+/* expand a file. we prefer to use ftruncate, as that is what posix
+ says to use for mmap expansion */
+static int expand_file(int fd, tdb_off size, tdb_off addition)
+{
+ char buf[1024];
+#if HAVE_FTRUNCATE_EXTEND
+ if (ftruncate(fd, size+addition) != 0) return -1;
+#else
+ char b = 0;
+ if (lseek(fd, (size+addition) - 1, SEEK_SET) != (size+addition) - 1 ||
+ write(fd, &b, 1) != 1) return -1;
+#endif
+ /* now fill the file with something. This ensures that the file isn't sparse, which would be
+ very bad if we ran out of disk. This must be done with write, not via mmap */
+ memset(buf, 0x42, sizeof(buf));
+ if (lseek(fd, size, SEEK_SET) != size) return -1;
+ while (addition) {
+ int n = addition>sizeof(buf)?sizeof(buf):addition;
+ int ret = write(fd, buf, n);
+ if (ret != n) return -1;
+ addition -= n;
+ }
+ return 0;
+}
+
+
/* expand the database at least size bytes by expanding the underlying
file and doing the mmap again if necessary */
static int tdb_expand(TDB_CONTEXT *tdb, tdb_off size)
{
struct list_struct rec;
tdb_off offset;
- char b = 0;
if (tdb_lock(tdb, -1, F_WRLCK) == -1) return 0;
@@ -449,10 +475,7 @@ static int tdb_expand(TDB_CONTEXT *tdb, tdb_off size)
/* expand the file itself */
if (!(tdb->flags & TDB_INTERNAL)) {
- if (lseek(tdb->fd, tdb->map_size + size - 1, SEEK_SET)!=tdb->map_size + size - 1)
- goto fail;
- if (write(tdb->fd, &b, 1) != 1)
- goto fail;
+ if (expand_file(tdb->fd, tdb->map_size, size) != 0) goto fail;
}
tdb->map_size += size;