1 files changed, 44 insertions, 0 deletions
diff --git a/usr/klibc/unsetenv.c b/usr/klibc/unsetenv.c
new file mode 100644
index 0000000..c5cc95a
--- /dev/null
+++ b/usr/klibc/unsetenv.c
@@ -0,0 +1,44 @@
+/*
+ * unsetenv.c
+ */
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include "env.h"
+
+int unsetenv(const char *name)
+{
+	size_t len;
+	char **p, *q;
+	const char *z;
+
+	if (!name || !name[0]) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	len = 0;
+	for (z = name; *z; z++) {
+		len++;
+		if (*z == '=') {
+			errno = EINVAL;
+			return -1;
+		}
+	}
+
+	if (!environ)
+		return 0;
+
+	for (p = environ; (q = *p); p++) {
+		if (!strncmp(name, q, len) && q[len] == '=')
+			break;
+	}
+
+	for (; (q = *p); p++) {
+		p[0] = p[1];
+	}
+
+	return 0;
+}