Add build system scaffolding and libc headers

1 files changed, 33 insertions, 0 deletions

diff --git a/lib/libc/stdlib/getenv.c b/lib/libc/stdlib/getenv.c
new file mode 100644
index 00000000..deb2b5f7
--- /dev/null
+++ b/lib/libc/stdlib/getenv.c
@@ -0,0 +1,33 @@
+#include <libc.h>
+#include <stddef.h>
+#include <atomic.h>
+
+extern char **environ;
+
+char *getenv(const char *name)
+{
+	LIBC_LOCK(libc.lock.environ);
+
+	for (char **env = environ; *env; env++) {
+		char *eq = NULL;
+		for (char *p = *env; *p; p++) {
+			if (*p == '=') {
+				eq = p;
+				break;
+			}
+			if (name[p - *env] != *p) {
+				break;
+			}
+		}
+		if (eq && name[eq - *env] == '\0') {
+			LIBC_UNLOCK(libc.lock.environ);
+			return eq + 1;
+		}
+	}
+
+	LIBC_UNLOCK(libc.lock.environ);
+
+	return NULL;
+}
+
+weak_reference(getenv, secure_getenv);