kernel: sysctl: Add initial sysctl implementation

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

1 files changed, 98 insertions, 0 deletions

diff --git a/sys/kern/kern_sysctl.c b/sys/kern/kern_sysctl.c
new file mode 100644
index 0000000..970bc70
--- /dev/null
+++ b/sys/kern/kern_sysctl.c
@@ -0,0 +1,98 @@
+/*
+ * 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/sysctl.h>
+#include <sys/errno.h>
+#include <vm/dynalloc.h>
+#include <string.h>
+
+#define HYRA_RELEASE "Hyra/" HYRA_ARCH " " \
+        HYRA_VERSION " "              \
+        HYRA_BUILDDATE
+
+static const char *hyra = "Hyra";
+static const char *hyra_version = HYRA_VERSION;
+static const char *osrelease = HYRA_RELEASE;
+
+static struct sysctl_entry common_kerntab[] = {
+    [KERN_OSTYPE] = { KERN_OSTYPE, SYSCTL_OPTYPE_STR_RO, &hyra },
+    [KERN_OSRELEASE] = { KERN_OSRELEASE, SYSCTL_OPTYPE_STR, &osrelease },
+    [KERN_VERSION] = { KERN_VERSION, SYSCTL_OPTYPE_STR, &hyra_version },
+};
+
+int
+sysctl(struct sysctl_args *args)
+{
+    struct sysctl_entry *tmp;
+    char *tmp_str;
+    size_t oldlen, len;
+
+    if (args->name == NULL) {
+        return -EINVAL;
+    }
+
+    if (args->oldlenp == NULL) {
+        return -EINVAL;
+    }
+
+    /* TODO: Support writable values */
+    if (args->newp != NULL) {
+        return -ENOTSUP;
+    }
+
+    /*
+     * TODO: We only support toplevel names as of now and should
+     *       expand this in the future. As of now, users will only
+     *       be able to access kern.* entries.
+     */
+    switch (*args->name) {
+    case KERN_OSTYPE:
+        tmp = &common_kerntab[KERN_OSTYPE];
+        tmp_str = *((char **)tmp->data);
+        len = strlen(tmp_str);
+        break;
+    case KERN_OSRELEASE:
+        tmp = &common_kerntab[KERN_OSRELEASE];
+        tmp_str = *((char **)tmp->data);
+        len = strlen(tmp_str);
+        break;
+    case KERN_VERSION:
+        tmp = &common_kerntab[KERN_VERSION];
+        tmp_str = *((char **)tmp->data);
+        len = strlen(tmp_str);
+        break;
+    default:
+        return -EINVAL;
+    }
+
+    /* Copy new data */
+    oldlen = *args->oldlenp;
+    memcpy(args->oldp, tmp_str, oldlen);
+    return (len > oldlen) ? -ENOMEM : 0;
+}