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authorMiles Bader <miles@gnu.org>1997-06-20 05:04:50 +0000
committerMiles Bader <miles@gnu.org>1997-06-20 05:04:50 +0000
commit0ff507a0ca5072f1a8b2ec00029c05dd93135012 (patch)
tree819a6cc4a82e7506eff89a9647152f2829008aa0
parentd3c9edebe8bc2067bf2e293e0693f873b2576713 (diff)
(store_read):
Limit reads to the amount available. Deallocate memory returned when reading part of a multiple-segment read.
-rw-r--r--libstore/rdwr.c36
1 files changed, 22 insertions, 14 deletions
diff --git a/libstore/rdwr.c b/libstore/rdwr.c
index 26f713eb..bb3f3079 100644
--- a/libstore/rdwr.c
+++ b/libstore/rdwr.c
@@ -1,9 +1,7 @@
/* Store I/O
- Copyright (C) 1995, 1996 Free Software Foundation, Inc.
-
+ Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
Written by Miles Bader <miles@gnu.ai.mit.edu>
-
This file is part of the GNU Hurd.
The GNU Hurd is free software; you can redistribute it and/or
@@ -18,7 +16,7 @@
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
- 675 Mass Ave, Cambridge, MA 02139, USA. */
+ 59 Temple Place - Suite 330, Boston, MA 02111, USA. */
#include <string.h>
@@ -165,22 +163,28 @@ error_t
store_read (struct store *store,
off_t addr, size_t amount, void **buf, size_t *len)
{
- error_t err;
size_t index;
- off_t base;
+ off_t base, first_run_size;
struct store_run *run, *runs_end;
int block_shift = store->log2_block_size;
store_read_meth_t read = store->class->read;
addr = store_find_first_run (store, addr, &run, &runs_end, &base, &index);
- if (addr < 0)
- err = EIO;
- else if ((run->length << block_shift) >= amount)
+ if (addr < 0 || run->start < 0)
+ return EIO; /* Reading from a hole. */
+
+ first_run_size = (run->length << block_shift);
+ if (first_run_size >= amount)
/* The first run has it all... */
- err = (*read)(store, base + run->start + addr, index, amount, buf, len);
+ {
+ if (first_run_size < amount)
+ amount = first_run_size;
+ return (*read)(store, base + run->start + addr, index, amount, buf, len);
+ }
else
/* ARGH, we've got to split up the read ... This isn't fun. */
{
+ error_t err;
int all;
/* WHOLE_BUF and WHOLE_BUF_LEN will point to a buff that's large enough
to hold the entire request. This is initially whatever the user
@@ -205,7 +209,11 @@ store_read (struct store *store,
to use the buffer space we so kindly gave it, bcopy it to
that space. */
if (seg_buf != buf_end)
- bcopy (seg_buf, buf_end, seg_buf_len);
+ {
+ bcopy (seg_buf, buf_end, seg_buf_len);
+ vm_deallocate (mach_task_self (),
+ (vm_address_t)seg_buf, seg_buf_len);
+ }
buf_end += seg_buf_len;
amount -= seg_buf_len;
*all = (seg_buf_len == len);
@@ -226,7 +234,7 @@ store_read (struct store *store,
buf_end = whole_buf;
- err = seg_read (base + run->start + addr, run->length << block_shift, &all);
+ err = seg_read (base + run->start + addr, first_run_size, &all);
while (!err && all && amount > 0
&& store_next_run (store, runs_end, &run, &base, &index))
{
@@ -263,8 +271,8 @@ store_read (struct store *store,
unused);
*buf = whole_buf;
}
- }
- return err;
+ return err;
+ }
}