[haiku-development] devfs: handle api_version (fwd)
- From: "François Revol" <revol@xxxxxxx>
- To: haiku-development@xxxxxxxxxxxxx
- Date: Thu, 07 Jun 2007 11:08:05 +0200 CEST
sf.net seems to think it's spam... eh
------ Forwarded Message: ------
To: "OpenBeOS-kernel" <open-beos-kernel-devel@xxxxxxxxxxxxxxxxxxxxx>
From: "François Revol" <revol@xxxxxxx>
Subject: devfs: handle api_version
Date: Thu, 07 Jun 2007 10:46:12 +0200 CEST
This patch should fix handling of unexisting/set-to-1 api_version from
drivers.
We currently assume it's always there and == 2 and copy the [de]select
hooks regardless.
As version 1 drivers are pre-R4 it's probably not that useful to
support those, and I could just make it reject api_version not here or
==1 instead.
It would avoid adding all that, so I didn't commit it yet, thoughts ?
François.
Index: src/system/kernel/fs/devfs.cpp
===================================================================
--- src/system/kernel/fs/devfs.cpp (revision 21343)
+++ src/system/kernel/fs/devfs.cpp (working copy)
@@ -134,7 +134,7 @@
static void get_device_name(struct devfs_vnode *vnode, char *buffer, size_t
size);
static status_t publish_device(struct devfs *fs, const char *path,
device_node_info *deviceNode,
pnp_devfs_driver_info *info,
- driver_entry *driver, device_hooks
*ops);
+ driver_entry *driver, device_hooks
*ops, int32 api_version);
/* the one and only allowed devfs instance */
@@ -193,8 +193,27 @@
// For a valid device driver the following exports are required
- uint32 *api_version;
- if (get_image_symbol(image, "api_version", B_SYMBOL_TYPE_DATA, (void
**)&api_version) != B_OK)
+ int32 default_api_version = 1;
+ int32 *api_version = &default_api_version;
+ if (get_image_symbol(image, "api_version", B_SYMBOL_TYPE_DATA, (void
**)&api_version) == B_OK) {
+ // According to Be newsletter, vol II, issue 36,
+ // version 2 added readv/writev, which we don't support, but
also select/deselect.
+ // So we must make sure not to use invalid pointers in
publish_device.
+#if B_CUR_DRIVER_API_VERSION != 2
+ // just in case someone decides to bump up the api version
+#error Add checks here for new vs old api version!
+#endif
+ if (*api_version > B_CUR_DRIVER_API_VERSION) {
+ dprintf("%s: api_version %ld not handled\n", name,
*api_version);
+ status = B_BAD_VALUE;
+ goto error1;
+ }
+ if (*api_version < 1) {
+ dprintf("%s: api_version invalid\n", name);
+ status = B_BAD_VALUE;
+ goto error1;
+ }
+ } else
dprintf("%s: api_version missing\n", name);
device_hooks *(*find_device)(const char *);
@@ -243,7 +262,7 @@
if (hooks != NULL
&& publish_device(sDeviceFileSystem, devicePaths[0],
- NULL, NULL, driver, hooks) == B_OK)
+ NULL, NULL, driver, hooks,
*api_version) == B_OK)
exported++;
}
@@ -594,7 +613,7 @@
static pnp_devfs_driver_info *
-create_new_driver_info(device_hooks *ops)
+create_new_driver_info(device_hooks *ops, int32 version)
{
pnp_devfs_driver_info *info = (pnp_devfs_driver_info
*)malloc(sizeof(pnp_devfs_driver_info));
if (info == NULL)
@@ -607,14 +626,24 @@
info->close = ops->close;
info->free = ops->free;
info->control = ops->control;
- info->select = ops->select;
- info->deselect = ops->deselect;
info->read = ops->read;
info->write = ops->write;
+ // depends on api_version
+ info->select = NULL;
+ info->deselect = NULL;
info->read_pages = NULL;
info->write_pages = NULL;
- // old devices can't know to do physical page access
+ // old devices can't know how to do physical page access
+
+ if (version >= 2) {
+ info->select = ops->select;
+ info->deselect = ops->deselect;
+
+ // ops->readv;
+ // ops->writev;
+ // we don't implement scatter-gather atm, so ignore those.
+ }
return info;
}
@@ -817,10 +846,10 @@
static status_t
publish_device(struct devfs *fs, const char *path, device_node_info
*deviceNode,
- pnp_devfs_driver_info *info, driver_entry *driver, device_hooks *ops)
+ pnp_devfs_driver_info *info, driver_entry *driver, device_hooks *ops,
int32 api_version)
{
- TRACE(("publish_device(path = \"%s\", node = %p, info = %p, hooks =
%p)\n",
- path, deviceNode, info, ops));
+ TRACE(("publish_device(path = \"%s\", node = %p, info = %p, hooks = %p,
api_version = %d)\n",
+ path, deviceNode, info, ops, api_version));
if (sDeviceFileSystem == NULL) {
panic("publish_device() called before devfs mounted\n");
@@ -858,7 +887,7 @@
if (deviceNode != NULL)
node->stream.u.dev.info = info;
else
- node->stream.u.dev.info = create_new_driver_info(ops);
+ node->stream.u.dev.info = create_new_driver_info(ops,
api_version);
node->stream.u.dev.node = deviceNode;
node->stream.u.dev.driver = driver;
@@ -2016,7 +2045,7 @@
goto err2;
//add_device(device);
- status = publish_device(sDeviceFileSystem, filename, node, info, NULL,
NULL);
+ status = publish_device(sDeviceFileSystem, filename, node, info, NULL,
NULL, 0);
if (status != B_OK)
goto err3;
//nudge();
@@ -2267,7 +2296,8 @@
extern "C" status_t
devfs_publish_device(const char *path, void *obsolete, device_hooks *ops)
{
- return publish_device(sDeviceFileSystem, path, NULL, NULL, NULL, ops);
+ // post R5: assume version 2
+ return publish_device(sDeviceFileSystem, path, NULL, NULL, NULL, ops,
2);
}
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