kernel: fs: Add procfs support

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

4 files changed, 370 insertions, 1 deletions

diff --git a/sys/fs/procfs.c b/sys/fs/procfs.c
new file mode 100644
index 0000000..3a0e2d3
--- /dev/null
+++ b/sys/fs/procfs.c
@@ -0,0 +1,206 @@
+/*
+ * 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/mount.h>
+#include <sys/queue.h>
+#include <sys/errno.h>
+#include <vm/dynalloc.h>
+#include <sys/vfs.h>
+#include <fs/procfs.h>
+#include <string.h>
+
+struct proc_node {
+    struct spinlock lock;
+    struct proc_entry *entry;
+    char *name;
+    TAILQ_ENTRY(proc_node) link;
+};
+
+static TAILQ_HEAD(, proc_node) proc_nodes;
+static bool nodelist_init = false;
+
+static struct proc_node *
+name_to_node(const char *name)
+{
+    struct proc_node *n;
+
+    TAILQ_FOREACH(n, &proc_nodes, link) {
+        if (strcmp(n->name, name) == 0) {
+            return n;
+        }
+    }
+
+    return NULL;
+}
+
+static int
+procfs_make_node(const char *name, struct proc_node **res)
+{
+    size_t name_len = 0;
+    const char *p = name;
+    struct proc_node *n;
+
+    /* Disallow paths */
+    for (; *p; ++p, ++name_len) {
+        if (*p == '/') {
+            return -EINVAL;
+        }
+    }
+
+    if (!vfs_is_valid_path(name))
+        return -EINVAL;
+
+    n = dynalloc(sizeof(struct proc_node));
+    if (n == NULL)
+        return -ENOMEM;
+
+    n->name = dynalloc(sizeof(char) * name_len);
+    if (n->name == NULL)
+        return -ENOMEM;
+
+    memcpy(n->name, name, name_len + 1);
+    *res = n;
+    return 0;
+}
+
+struct proc_entry *
+procfs_alloc_entry(void)
+{
+    struct proc_entry *entry;
+
+    entry = dynalloc(sizeof(*entry));
+    if (entry == NULL)
+        return NULL;
+
+    memset(entry, 0, sizeof(*entry));
+    return entry;
+}
+
+int
+procfs_add_entry(const char *name, struct proc_entry *entry)
+{
+    struct proc_node *proc;
+    int status;
+
+    if (name == NULL || entry == NULL)
+        return -EINVAL;
+    if ((status = procfs_make_node(name, &proc)) != 0)
+        return status;
+
+    proc->entry = entry;
+    TAILQ_INSERT_HEAD(&proc_nodes, proc, link);
+    return 0;
+}
+
+static int
+procfs_init(struct fs_info *info, struct vnode *source)
+{
+    if (source != NULL)
+        return -EINVAL;
+
+
+    TAILQ_INIT(&proc_nodes);
+    nodelist_init = true;
+    procfs_populate();
+    return 0;
+}
+
+static int
+procfs_rw_vnode(struct vnode *vp, struct sio_txn *sio, bool write)
+{
+    struct proc_node *proc;
+    struct proc_entry *entry;
+
+    if (vp == NULL)
+        return -EIO;
+
+    proc = vp->data;
+    entry = proc->entry;
+
+    return write ? entry->write(entry, sio)
+                 : entry->read(entry, sio);
+}
+
+static int
+vop_write(struct vnode *vp, struct sio_txn *sio)
+{
+    return procfs_rw_vnode(vp, sio, true);
+}
+
+static int
+vop_read(struct vnode *vp, struct sio_txn *sio)
+{
+    return procfs_rw_vnode(vp, sio, false);
+}
+
+static int
+vop_open(struct vnode *vp)
+{
+    return 0;
+}
+
+static int
+vop_close(struct vnode *vp)
+{
+    return 0;
+}
+
+static int
+vop_vget(struct vnode *parent, const char *name, struct vnode **vp)
+{
+    struct proc_node *proc;
+    struct vnode *vnode;
+    int status;
+
+    if (!nodelist_init)
+        return -EIO;
+    if ((proc = name_to_node(name)) == NULL)
+        return -ENOENT;
+    if ((status = vfs_alloc_vnode(&vnode, NULL, VREG)) != 0)
+        return status;
+
+    vnode->parent = parent;
+    vnode->data = proc;
+    vnode->vops = &g_procfs_vops;
+    *vp = vnode;
+    return 0;
+}
+
+struct vfsops g_procfs_ops = {
+    .init = procfs_init
+};
+
+struct vops g_procfs_vops = {
+    .vget = vop_vget,
+    .read = vop_read,
+    .write = vop_write,
+    .open = vop_open,
+    .close = vop_close
+};
diff --git a/sys/fs/procfs_subr.c b/sys/fs/procfs_subr.c
new file mode 100644
index 0000000..e368d56
--- /dev/null
+++ b/sys/fs/procfs_subr.c
@@ -0,0 +1,109 @@
+/*
+ * 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/panic.h>
+#include <machine/cpu.h>
+#include <fs/procfs.h>
+#include <vm/vm.h>
+#include <string.h>
+
+static bool populated = false;
+
+static int
+procfs_ver_read(struct proc_entry *p, struct sio_txn *sio)
+{
+    char buf[1024];
+    size_t len;
+
+    len = snprintf(buf, sizeof(buf), "Hyra/%s v%s: %s (%s)",
+                   HYRA_ARCH, HYRA_VERSION,
+                   HYRA_BUILDDATE, HYRA_BUILDBRANCH);
+
+    /* Truncate if needed */
+    if (len > sio->len)
+        len = sio->len;
+
+    memcpy(sio->buf, buf, len);
+    return len;
+}
+
+static int
+procfs_memstat_read(struct proc_entry *p, struct sio_txn *sio)
+{
+    struct vm_memstat stat;
+    struct physmem_stat *pstat;
+    char buf[1024];
+    size_t len;
+
+    stat = vm_memstat();
+    pstat = &stat.pmem_stat;
+    len = snprintf(buf, sizeof(buf),
+                   "TotalMem:      %d KiB\n"
+                   "ReservedMem:   %d KiB\n"
+                   "AvailableMem:  %d KiB\n"
+                   "AllocatedMem:  %d KiB\n"
+                   "VMemObjCount:  %d",
+                   pstat->total_kib,
+                   pstat->reserved_kib,
+                   pstat->avl_kib,
+                   pstat->alloc_kib,
+                   stat.vmobj_cnt);
+
+    /* Truncate if needed */
+    if (len > sio->len)
+        len = sio->len;
+
+    memcpy(sio->buf, buf, len);
+    return len;
+}
+
+/*
+ * Populate procfs with basic misc entries
+ */
+void
+procfs_populate(void)
+{
+    struct proc_entry *version;
+    struct proc_entry *memstat;
+
+    if (populated)
+        return;
+
+    populated = true;
+
+    /* Kernel version */
+    version = procfs_alloc_entry();
+    version->read = procfs_ver_read;
+    procfs_add_entry("version", version);
+
+    /* Memstat */
+    memstat = procfs_alloc_entry();
+    memstat->read = procfs_memstat_read;
+    procfs_add_entry("memstat", memstat);
+}
diff --git a/sys/include/fs/procfs.h b/sys/include/fs/procfs.h
new file mode 100644
index 0000000..ed3a19f
--- /dev/null
+++ b/sys/include/fs/procfs.h
@@ -0,0 +1,51 @@
+/*
+ * 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.
+ */
+
+#ifndef _PROCFS_H_
+#define _PROCFS_H_
+
+#include <sys/types.h>
+#include <sys/mount.h>
+#include <sys/sio.h>
+
+struct proc_entry {
+    int(*read)(struct proc_entry *p, struct sio_txn *sio);
+    int(*write)(struct proc_entry *p, struct sio_txn *sio);
+};
+
+extern struct vfsops g_procfs_ops;
+extern struct vops g_procfs_vops;
+
+int procfs_add_entry(const char *name, struct proc_entry *entry);
+struct proc_entry *procfs_alloc_entry(void);
+
+/* procfs_subr.c */
+void procfs_populate(void);
+
+#endif  /* !_PROCFS_H_ */
diff --git a/sys/kern/vfs_init.c b/sys/kern/vfs_init.c
index fa20af3..6754b1f 100644
--- a/sys/kern/vfs_init.c
+++ b/sys/kern/vfs_init.c
@@ -34,6 +34,7 @@
 #include <sys/vnode.h>
 #include <fs/initramfs.h>
 #include <fs/devfs.h>
+#include <fs/procfs.h>
 #include <assert.h>
 #include <string.h>
 
@@ -43,10 +44,12 @@ __KERNEL_META("$Hyra$: vfs.c, Ian Marco Moffett, "
 
 #define INITRAMFS_ID 0
 #define DEVFS_ID 1
+#define PROCFS_ID 2
 
 static struct fs_info filesystems[] = {
     [INITRAMFS_ID] = { "initramfs", &g_initramfs_ops, NULL},
-    [DEVFS_ID]     = { "dev", &g_devfs_ops, &g_devfs_vops }
+    [DEVFS_ID]     = { "dev", &g_devfs_ops, &g_devfs_vops },
+    [PROCFS_ID]    = { "proc", &g_procfs_ops, &g_procfs_vops }
 };
 
 struct vnode *g_root_vnode = NULL;