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# HG changeset patch
# User Keir Fraser <keir.fraser@citrix.com>
# Date 1216203201 -3600
# Node ID 649c975b72f00eff06659d683b9999dffec1063a
# Parent 45787d746db410deaa4cb7249e35d42cd8d01a9c
fs-backend: do not expose file descriptors to frontend

Signed-off-by: Samuel Thibault <samuel.thibault@eu.citrix.com>
---
tools/fs-back/fs-backend.c | 3 +
tools/fs-back/fs-backend.h | 2 +
tools/fs-back/fs-ops.c | 80 ++++++++++++++++++++++++++++++++++++---------
3 files changed, 70 insertions(+), 15 deletions(-)

diff -r 45787d746db4 -r 649c975b72f0 tools/fs-back/fs-backend.c
--- a/tools/fs-back/fs-backend.c Wed Jul 16 11:12:36 2008 +0100
+++ b/tools/fs-back/fs-backend.c Wed Jul 16 11:13:21 2008 +0100
@@ -198,6 +198,7 @@ static void handle_connection(int fronte
int evt_port;
pthread_t handling_thread;
struct fsif_sring *sring;
+ int i;

printf("Handling connection from dom=%d, for export=%d\n",
frontend_dom_id, export_id);
@@ -240,6 +241,8 @@ static void handle_connection(int fronte
PROT_READ | PROT_WRITE);
BACK_RING_INIT(&mount->ring, sring, PAGE_SIZE);
mount->nr_entries = mount->ring.nr_ents;
+ for (i = 0; i < MAX_FDS; i++)
+ mount->fds[i] = -1;
xenbus_write_backend_ready(mount);

pthread_create(&handling_thread, NULL, &handle_mount, mount);
diff -r 45787d746db4 -r 649c975b72f0 tools/fs-back/fs-backend.h
--- a/tools/fs-back/fs-backend.h Wed Jul 16 11:12:36 2008 +0100
+++ b/tools/fs-back/fs-backend.h Wed Jul 16 11:13:21 2008 +0100
@@ -12,6 +12,7 @@
#define EXPORTS_SUBNODE "exports"
#define EXPORTS_NODE ROOT_NODE"/"EXPORTS_SUBNODE
#define WATCH_NODE EXPORTS_NODE"/requests"
+#define MAX_FDS 16

struct fs_export
{
@@ -45,6 +46,7 @@ struct mount
int nr_entries;
struct fs_request *requests;
unsigned short *freelist;
+ int fds[MAX_FDS];
};


diff -r 45787d746db4 -r 649c975b72f0 tools/fs-back/fs-ops.c
--- a/tools/fs-back/fs-ops.c Wed Jul 16 11:12:36 2008 +0100
+++ b/tools/fs-back/fs-ops.c Wed Jul 16 11:13:21 2008 +0100
@@ -34,6 +34,16 @@ unsigned short get_request(struct mount
return id;
}

+int get_fd(struct mount *mount)
+{
+ int i;
+
+ for (i = 0; i < MAX_FDS; i++)
+ if (mount->fds[i] == -1)
+ return i;
+ return -1;
+}
+

void dispatch_file_open(struct mount *mount, struct fsif_request *req)
{
@@ -59,8 +69,17 @@ void dispatch_file_open(struct mount *mo
mount->export->export_path, file_name);
assert(xc_gnttab_munmap(mount->gnth, file_name, 1) == 0);
printf("Issuing open for %s\n", full_path);
- fd = open(full_path, O_RDWR);
- printf("Got FD: %d\n", fd);
+ fd = get_fd(mount);
+ if (fd >= 0) {
+ int real_fd = open(full_path, O_RDWR);
+ if (real_fd < 0)
+ fd = -1;
+ else
+ {
+ mount->fds[fd] = real_fd;
+ printf("Got FD: %d for real %d\n", fd, real_fd);
+ }
+ }
/* We can advance the request consumer index, from here on, the request
* should not be used (it may be overrinden by a response) */
mount->ring.req_cons++;
@@ -84,7 +103,12 @@ void dispatch_file_close(struct mount *m
printf("Dispatching file close operation (fd=%d).\n", req->u.fclose.fd);

req_id = req->id;
- ret = close(req->u.fclose.fd);
+ if (req->u.fclose.fd < MAX_FDS) {
+ int fd = mount->fds[req->u.fclose.fd];
+ ret = close(fd);
+ mount->fds[req->u.fclose.fd] = -1;
+ } else
+ ret = -1;
printf("Got ret: %d\n", ret);
/* We can advance the request consumer index, from here on, the request
* should not be used (it may be overrinden by a response) */
@@ -115,7 +139,12 @@ void dispatch_file_read(struct mount *mo
req_id = req->id;
printf("File read issued for FD=%d (len=%"PRIu64", offest=%"PRIu64")\n",
req->u.fread.fd, req->u.fread.len, req->u.fread.offset);
-
+
+ if (req->u.fread.fd < MAX_FDS)
+ fd = mount->fds[req->u.fread.fd];
+ else
+ fd = -1;
+
priv_id = get_request(mount, req);
printf("Private id is: %d\n", priv_id);
priv_req = &mount->requests[priv_id];
@@ -123,13 +152,13 @@ void dispatch_file_read(struct mount *mo

/* Dispatch AIO read request */
bzero(&priv_req->aiocb, sizeof(struct aiocb));
- priv_req->aiocb.aio_fildes = req->u.fread.fd;
+ priv_req->aiocb.aio_fildes = fd;
priv_req->aiocb.aio_nbytes = req->u.fread.len;
priv_req->aiocb.aio_offset = req->u.fread.offset;
priv_req->aiocb.aio_buf = buf;
assert(aio_read(&priv_req->aiocb) >= 0);

-
+out:
/* We can advance the request consumer index, from here on, the request
* should not be used (it may be overrinden by a response) */
mount->ring.req_cons++;
@@ -171,6 +200,11 @@ void dispatch_file_write(struct mount *m
printf("File write issued for FD=%d (len=%"PRIu64", offest=%"PRIu64")\n",
req->u.fwrite.fd, req->u.fwrite.len, req->u.fwrite.offset);

+ if (req->u.fwrite.fd < MAX_FDS)
+ fd = mount->fds[req->u.fwrite.fd];
+ else
+ fd = -1;
+
priv_id = get_request(mount, req);
printf("Private id is: %d\n", priv_id);
priv_req = &mount->requests[priv_id];
@@ -178,7 +212,7 @@ void dispatch_file_write(struct mount *m

/* Dispatch AIO write request */
bzero(&priv_req->aiocb, sizeof(struct aiocb));
- priv_req->aiocb.aio_fildes = req->u.fwrite.fd;
+ priv_req->aiocb.aio_fildes = fd;
priv_req->aiocb.aio_nbytes = req->u.fwrite.len;
priv_req->aiocb.aio_offset = req->u.fwrite.offset;
priv_req->aiocb.aio_buf = buf;
@@ -224,8 +258,12 @@ void dispatch_stat(struct mount *mount,
PROT_WRITE);

req_id = req->id;
- fd = req->u.fstat.fd;
- printf("File stat issued for FD=%d\n", fd);
+ if (req->u.fstat.fd < MAX_FDS)
+ fd = mount->fds[req->u.fstat.fd];
+ else
+ fd = -1;
+
+ printf("File stat issued for FD=%d\n", req->u.fstat.fd);

/* We can advance the request consumer index, from here on, the request
* should not be used (it may be overrinden by a response) */
@@ -274,10 +312,14 @@ void dispatch_truncate(struct mount *mou
int64_t length;

req_id = req->id;
- fd = req->u.ftruncate.fd;
length = req->u.ftruncate.length;
- printf("File truncate issued for FD=%d, length=%"PRId64"\n", fd, length);
-
+ printf("File truncate issued for FD=%d, length=%"PRId64"\n", req->u.ftruncate.fd, length);
+
+ if (req->u.ftruncate.fd < MAX_FDS)
+ fd = mount->fds[req->u.ftruncate.fd];
+ else
+ fd = -1;
+
/* We can advance the request consumer index, from here on, the request
* should not be used (it may be overrinden by a response) */
mount->ring.req_cons++;
@@ -510,7 +552,11 @@ void dispatch_chmod(struct mount *mount,
printf("Dispatching file chmod operation (fd=%d, mode=%o).\n",
req->u.fchmod.fd, req->u.fchmod.mode);
req_id = req->id;
- fd = req->u.fchmod.fd;
+ if (req->u.fchmod.fd < MAX_FDS)
+ fd = mount->fds[req->u.fchmod.fd];
+ else
+ fd = -1;
+
mode = req->u.fchmod.mode;
/* We can advance the request consumer index, from here on, the request
* should not be used (it may be overrinden by a response) */
@@ -575,8 +621,12 @@ void dispatch_file_sync(struct mount *mo
struct fs_request *priv_req;

req_id = req->id;
- fd = req->u.fsync.fd;
- printf("File sync issued for FD=%d\n", fd);
+ if (req->u.fsync.fd < MAX_FDS)
+ fd = mount->fds[req->u.fsync.fd];
+ else
+ fd = -1;
+
+ printf("File sync issued for FD=%d\n", req->u.fsync.fd);

priv_id = get_request(mount, req);
printf("Private id is: %d\n", priv_id);

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