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authorIan Moffett <ian@osmora.org>2024-07-12 00:07:22 -0400
committerIan Moffett <ian@osmora.org>2024-07-12 00:07:22 -0400
commitd117265f1e2b465c29c919a7ad594232d645cf76 (patch)
tree2f758801628660f19783c5a3b31e3cbb2dec352a /sys/fs
parente93f80c60a900b747792cda7176c59521401821b (diff)
kernel: Add support for devfs
Signed-off-by: Ian Moffett <ian@osmora.org>
Diffstat (limited to 'sys/fs')
-rw-r--r--sys/fs/devfs.c190
1 files changed, 190 insertions, 0 deletions
diff --git a/sys/fs/devfs.c b/sys/fs/devfs.c
new file mode 100644
index 0000000..c1eb761
--- /dev/null
+++ b/sys/fs/devfs.c
@@ -0,0 +1,190 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <sys/vnode.h>
+#include <sys/errno.h>
+#include <sys/mount.h>
+#include <sys/device.h>
+#include <fs/devfs.h>
+#include <vm/dynalloc.h>
+#include <string.h>
+
+struct devfs_node {
+ const char *name;
+ uint8_t is_block : 1;
+ mode_t mode;
+ devmajor_t major;
+ dev_t dev;
+ TAILQ_ENTRY(devfs_node) link;
+};
+
+static TAILQ_HEAD(, devfs_node) devlist;
+
+static inline int
+cdevsw_read(void *devsw, dev_t dev, struct sio_txn *sio)
+{
+ struct cdevsw *cdevsw = devsw;
+
+ return cdevsw->read(dev, sio, 0);
+}
+
+/*
+ * Get a devfs node by name.
+ *
+ * @name: Name to lookup.
+ */
+static struct devfs_node *
+devfs_get_node(const char *name)
+{
+ struct devfs_node *dnp;
+
+ TAILQ_FOREACH(dnp, &devlist, link) {
+ if (strcmp(dnp->name, name) == 0) {
+ return dnp;
+ }
+ }
+
+ return NULL;
+}
+
+static int
+devfs_lookup(struct vop_lookup_args *args)
+{
+ int vtype, error;
+ const char *name = args->name;
+ struct devfs_node *dnp;
+ struct vnode *vp;
+
+ if (*name == '/')
+ ++name;
+
+ /* Make sure it isn't a path */
+ for (const char *p = name; *p != '\0'; ++p) {
+ if (*p == '/') {
+ return -ENOENT;
+ }
+ }
+
+ if ((dnp = devfs_get_node(name)) == NULL)
+ return -ENOENT;
+
+ /* Now, create a vnode */
+ vtype = (dnp->is_block) ? VBLK : VCHR;
+ if ((error = vfs_alloc_vnode(&vp, vtype)) != 0)
+ return error;
+
+ vp->data = dnp;
+ vp->vops = &g_devfs_vops;
+ *args->vpp = vp;
+ return 0;
+}
+
+static int
+devfs_reclaim(struct vnode *vp)
+{
+ if (vp->data != NULL)
+ dynfree(vp->data);
+
+ vp->data = NULL;
+ return 0;
+}
+
+static int
+devfs_read(struct vnode *vp, struct sio_txn *sio)
+{
+ struct devfs_node *dnp;
+ void *devsw;
+
+ if ((dnp = vp->data) == NULL)
+ return -EIO;
+
+ devsw = dev_get(dnp->major, dnp->dev);
+
+ if (!dnp->is_block)
+ return cdevsw_read(devsw, dnp->dev, sio);
+
+ /* TODO: Block devices */
+ return -EIO;
+}
+
+static int
+devfs_init(struct fs_info *fip)
+{
+ struct vnode *vp;
+ struct mount *mp;
+ int error;
+
+ /* Create a new vnode for devfs */
+ if ((error = vfs_alloc_vnode(&vp, VDIR)) != 0)
+ return error;
+
+ vp->vops = &g_devfs_vops;
+ TAILQ_INIT(&devlist);
+ mp = vfs_alloc_mount(vp, fip);
+
+ vfs_name_mount(mp, "dev");
+ TAILQ_INSERT_TAIL(&g_mountlist, mp, mnt_list);
+ return 0;
+}
+
+/*
+ * Create an entry within devfs.
+ *
+ * @name: Device name.
+ * @major: Device major.
+ * @dev: Device minor.
+ * @mode: Permissions mask
+ */
+int
+devfs_create_entry(const char *name, devmajor_t major, dev_t dev, mode_t mode)
+{
+ struct devfs_node *dnp;
+
+ dnp = dynalloc(sizeof(*dnp));
+ if (dnp == NULL)
+ return -ENOMEM;
+
+ dnp->name = name;
+ dnp->major = major;
+ dnp->dev = dev;
+ dnp->mode = mode;
+ TAILQ_INSERT_TAIL(&devlist, dnp, link);
+ return 0;
+}
+
+const struct vops g_devfs_vops = {
+ .lookup = devfs_lookup,
+ .reclaim = devfs_reclaim,
+ .read = devfs_read
+};
+
+const struct vfsops g_devfs_vfsops = {
+ .init = devfs_init
+};