Add build system scaffolding and libc headers

1 files changed, 55 insertions, 0 deletions

diff --git a/lib/libc/unistd/execvp.c b/lib/libc/unistd/execvp.c
new file mode 100644
index 00000000..2ce69354
--- /dev/null
+++ b/lib/libc/unistd/execvp.c
@@ -0,0 +1,55 @@
+#include <errno.h>
+#include <limits.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdio.h>
+
+extern char **environ;
+
+int execvp(const char *file, char *const argv[])
+{
+	if (*file == '\0') {
+		errno = ENOENT;
+		return -1;
+	}
+
+	if (strchr(file, '/') != NULL) {
+		return execv(file, argv);
+	} else {
+		char *ptr;
+		char *path = NULL; // TODO: getenv
+
+		if (path == NULL || *path == '\0') {
+			path = "/bin";
+		}
+
+		do {
+			char buf[PATH_MAX];
+
+			if ((ptr = strchr(path, ':')) == NULL) {
+				if (snprintf(buf, PATH_MAX, "%s/%s", path,
+					     file) >= PATH_MAX) {
+					errno = ENAMETOOLONG;
+					return -1;
+				}
+
+				execv(buf, argv);
+				break;
+			}
+
+			if (snprintf(buf, PATH_MAX, "%.*s/%s",
+				     (int)(ptr - path), path,
+				     file) >= PATH_MAX) {
+				errno = ENAMETOOLONG;
+				return -1;
+			}
+
+			execv(buf, argv);
+		} while (*ptr != '\0');
+
+		errno = ENOENT;
+		return -1;
+	}
+
+	return 0;
+}