usr.bin: Add initial getconf impl

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

2 files changed, 96 insertions, 0 deletions

diff --git a/usr.bin/getconf/Makefile b/usr.bin/getconf/Makefile
new file mode 100644
index 0000000..48c05a8
--- /dev/null
+++ b/usr.bin/getconf/Makefile
@@ -0,0 +1,6 @@
+include user.mk
+
+CFILES = $(shell find . -name "*.c")
+
+$(ROOT)/base/usr/bin/getconf:
+	gcc $(CFILES) -Iinclude/ -o $@ $(INTERNAL_CFLAGS)
diff --git a/usr.bin/getconf/getconf.c b/usr.bin/getconf/getconf.c
new file mode 100644
index 0000000..c60bf5d
--- /dev/null
+++ b/usr.bin/getconf/getconf.c
@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2023-2025 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/param.h>
+#include <sys/limits.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+
+struct sysvar {
+    const char *var;
+    uint8_t auxv : 1;
+    uint8_t val;
+};
+
+static struct sysvar vartab[] = {
+    { "PAGESIZE", 1, AT_PAGESIZE },
+    { "CHAR_BIT", 0, CHAR_BIT },
+    { NULL, 0, 0 }
+};
+
+static int
+getvar_val(struct sysvar *vp)
+{
+    if (vp->auxv) {
+        return sysconf(vp->val);
+    }
+
+    return vp->val;
+}
+
+static int
+getvar(const char *sysvar)
+{
+    for (int i = 0; vartab[i].var != NULL; ++i) {
+        if (strcmp(vartab[i].var, sysvar) == 0) {
+            return getvar_val(&vartab[i]);
+        }
+    }
+
+    return -1;
+}
+
+int
+main(int argc, char **argv)
+{
+    char *var;
+    int retval;
+
+    if (argc < 2) {
+        printf("usage: getconf <SYSTEM VAR>\n");
+        return -1;
+    }
+
+    var = argv[1];
+    if ((retval = getvar(var)) < 0) {
+        printf("bad system var \"%s\"\n", var);
+        return retval;
+    }
+
+    printf("%d\n", retval);
+    return 0;
+}