1 files changed, 83 insertions, 0 deletions
diff --git a/getopt.c b/getopt.c
new file mode 100644
index 0000000..5f6baaa
--- /dev/null
+++ b/getopt.c
@@ -0,0 +1,83 @@
+#include <sys/types.h>
+#include <string.h>
+#include <stdio.h>
+#include <unistd.h>
+
+int sh_getopt(int argc, char * const argv[], const char *optstring)
+{
+	static int optchar = 0;
+	char *option = NULL;
+
+	if (optind == 0) {
+		optind = 1;
+		optchar = 0;
+	}
+
+	if (argv[optind] == NULL) {
+		return -1;
+	}
+
+	if (argv[optind][0] != '-') {
+		return -1;
+	}
+
+	if (!strcmp(argv[optind], "-")) {
+		return -1;
+	}
+
+	if (!strcmp(argv[optind], "--")) {
+		optind++;
+		optchar = 0;
+		return -1;
+	}
+
+	if (optchar == 0 && argv[optind][optchar] != '-') {
+		return -1;
+	}
+
+	optchar++;
+
+	if (argv[optind][optchar] == '\0') {
+		optind++;
+		optchar = 0;
+		return getopt(argc, argv, optstring);
+	}
+
+	option = strchr(optstring, argv[optind][optchar]);
+
+	if (!option) {
+		optopt = argv[optind][optchar];
+		if (opterr != 0 && optstring[0] != ':') {
+			fprintf(stderr, "%s: invalid option -%c\n", argv[0],
+			optopt);
+		}
+		return '?';
+	}
+
+	if (option[1] != ':') {
+		return *option;
+	}
+
+	if (argv[optind][optchar + 1] == '\0') {
+		optarg = argv[++optind];
+	} else {
+		optarg = argv[optind] + optchar + 1;
+	}
+
+	optind++;
+	if (optarg == NULL) {
+		optopt = *option;
+		if (opterr != 0 && optstring[0] != ':') {
+			fprintf(stderr, "%s: missing argument to option -%c\n",
+			argv[0], optopt);
+		}
+		return optstring[0] == ':' ? ':' : '?';
+	}
+
+	optchar = 0;
+	return *option;
+}
+
+/*
+POSIX(2)
+*/