1 files changed, 114 insertions, 0 deletions
diff --git a/lib/libc/unistd/getopt.c b/lib/libc/unistd/getopt.c
new file mode 100644
index 00000000..8ef18d37
--- /dev/null
+++ b/lib/libc/unistd/getopt.c
@@ -0,0 +1,114 @@
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/uio.h>
+
+char *optarg;
+int optind = 1, opterr = 1, optopt;
+
+int getopt(int argc, char *const argv[], const char *optstring)
+{
+	char *optchar;
+	char c, d;
+	int i;
+	static int optpos;
+
+	if (optind == 0) {
+		optpos = 0;
+		optind = 1;
+	}
+
+	if (optind >= argc || !argv[optind]) {
+		return -1;
+	}
+
+	if (argv[optind][0] != '-') {
+		if (optstring[0] == '-') {
+			optarg = argv[optind++];
+			return 1;
+		}
+
+		return -1;
+	}
+
+	if (argv[optind][1] == 0) {
+		return -1;
+	}
+
+	if (argv[optind][1] == '-' && argv[optind][2] == 0) {
+		return optind++, -1;
+	}
+
+	if (optpos == 0)
+		optpos++;
+
+	c = argv[optind][optpos];
+	optchar = argv[optind] + optpos++;
+
+	if (argv[optind][optpos] == 0) {
+		optind++;
+		optpos = 0;
+	}
+
+	i = 0;
+
+	do {
+		d = optstring[i++];
+	} while (d && d != c);
+
+	if (d != c || c == ':') {
+		optopt = c;
+		if (optstring[0] != ':' && opterr) {
+			struct iovec iov[4];
+			char opt_char[2] = { *optchar, '\0' };
+
+			iov[0].iov_base = argv[0];
+			iov[0].iov_len = strlen(argv[0]);
+			iov[1].iov_base = ": invalid option -- ";
+			iov[1].iov_len = 20;
+			iov[2].iov_base = opt_char;
+			iov[2].iov_len = 1;
+			iov[3].iov_base = "\n";
+			iov[3].iov_len = 1;
+
+			writev(STDERR_FILENO, iov, 4);
+		}
+		return '?';
+	}
+
+	if (optstring[i] == ':') {
+		optarg = 0;
+		if (optstring[i + 1] != ':' || optpos) {
+			optarg = argv[optind++];
+			if (optpos) {
+				optarg += optpos;
+			}
+			optpos = 0;
+		}
+		if (optind > argc) {
+			optopt = c;
+			if (optstring[0] == ':') {
+				return ':';
+			}
+			if (opterr) {
+				struct iovec iov[4];
+				char opt_char[2] = { *optchar, '\0' };
+
+				iov[0].iov_base = argv[0];
+				iov[0].iov_len = strlen(argv[0]);
+				iov[1].iov_base =
+					": option requires an argument -- ";
+				iov[1].iov_len = 33;
+				iov[2].iov_base = opt_char;
+				iov[2].iov_len = 1;
+				iov[3].iov_base = "\n";
+				iov[3].iov_len = 1;
+
+				writev(STDERR_FILENO, iov, 4);
+			}
+			return '?';
+		}
+	}
+
+	return c;
+}