usr: libc: Implement POSIX sysconf()

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

2 files changed, 44 insertions, 0 deletions

diff --git a/lib/libc/include/unistd.h b/lib/libc/include/unistd.h
index 70908c8..8c82eb8 100644
--- a/lib/libc/include/unistd.h
+++ b/lib/libc/include/unistd.h
@@ -30,6 +30,7 @@
 #ifndef _UNISTD_H
 #define _UNISTD_H
 
+#include <sys/exec.h>
 #include <sys/types.h>
 #include <sys/cdefs.h>
 #include <stddef.h>
@@ -43,6 +44,7 @@
 
 __BEGIN_DECLS
 
+int sysconf(int name);
 ssize_t read(int fd, void *buf, size_t count);
 ssize_t write(int fd, const void *buf, size_t count);
 
diff --git a/lib/libc/src/unistd/sysconf.c b/lib/libc/src/unistd/sysconf.c
new file mode 100644
index 0000000..43fab01
--- /dev/null
+++ b/lib/libc/src/unistd/sysconf.c
@@ -0,0 +1,42 @@
+/*
+ * 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 <unistd.h>
+
+extern uint64_t __libc_auxv[_AT_MAX];
+
+int
+sysconf(int name)
+{
+    if (name >= _AT_MAX) {
+        return -1;
+    }
+
+    return __libc_auxv[name];
+}