kern: vfs: Add initial namei() groundwork

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 100 insertions, 0 deletions

diff --git a/sys/kern/kern_namei.c b/sys/kern/kern_namei.c
new file mode 100644
index 0000000..ab96f75
--- /dev/null
+++ b/sys/kern/kern_namei.c
@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2025 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/errno.h>
+#include <sys/limits.h>
+#include <os/mount.h>
+#include <kern/namei.h>
+
+#include <os/trace.h>
+
+int
+namei(struct nameidata *ndp)
+{
+    struct mount *mpoint = NULL;
+    struct vnode *vp = NULL;
+    const char *p;
+    int error;
+    char namebuf[NAME_MAX];
+    size_t namebuf_idx = 0;
+
+    if (ndp == NULL) {
+        return -EINVAL;
+    }
+
+    if (ndp->pathname == NULL || ndp->vp_res == NULL) {
+        return -EINVAL;
+    }
+
+    trace("f: %s\n", ndp->pathname);
+
+    /* Iterate through the path */
+    p = ndp->pathname;
+    while (*p != '\0') {
+        /* Skip leading slashes */
+        while (*p != '\0' && *p == '/') {
+            *p++;
+        }
+
+        if (*p == '\0') {
+            break;
+        }
+
+        /* Fill the name buffer */
+        while (*p != '\0' && *p != '/') {
+            namebuf[namebuf_idx++] = *p++;
+            if (namebuf_idx >= sizeof(namebuf) - 1) {
+                break;
+            }
+            namebuf[namebuf_idx] = '\0';
+        }
+
+        /*
+         * If we have't yet looked up a mountpoint, do that and
+         * see if it was found.
+         */
+        if (mpoint == NULL) {
+            error = mount_lookup(namebuf, &mpoint);
+
+            if (error != 0)
+                return error;
+            if ((vp = mpoint->vp) == NULL)
+                return -EIO;
+
+            namebuf_idx = 0;
+            continue;
+        }
+
+        trace("d: %s\n", namebuf);
+        namebuf_idx = 0;
+    }
+
+    ndp->vp_res = vp;
+    return 0;
+}