libbb: add forgotten part of "script" applet change

libbb/getpty.c

@@ -0,0 +1,56 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Mini getpty implementation for busybox
+ * Bjorn Wesen, Axis Communications AB (bjornw@axis.com)
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ */
+
+#include "libbb.h"
+
+int getpty(char *line, int size)
+{
+	int p;
+#if ENABLE_FEATURE_DEVPTS
+	p = open("/dev/ptmx", O_RDWR);
+	if (p > 0) {
+		const char *name;
+		grantpt(p);
+		unlockpt(p);
+		name = ptsname(p);
+		if (!name) {
+			bb_perror_msg("ptsname error (is /dev/pts mounted?)");
+			return -1;
+		}
+		safe_strncpy(line, name, size);
+		return p;
+	}
+#else
+	struct stat stb;
+	int i;
+	int j;
+
+	strcpy(line, "/dev/ptyXX");
+
+	for (i = 0; i < 16; i++) {
+		line[8] = "pqrstuvwxyzabcde"[i];
+		line[9] = '0';
+		if (stat(line, &stb) < 0) {
+			continue;
+		}
+		for (j = 0; j < 16; j++) {
+			line[9] = j < 10 ? j + '0' : j - 10 + 'a';
+			if (DEBUG)
+				fprintf(stderr, "Trying to open device: %s\n", line);
+			p = open(line, O_RDWR | O_NOCTTY);
+			if (p >= 0) {
+				line[5] = 't';
+				return p;
+			}
+		}
+	}
+#endif /* FEATURE_DEVPTS */
+	return -1;
+}
+
+