From: Nathan Wagner <nw@hydaspes.if.org>
Date: Mon, 25 Mar 2019 13:41:39 +0000 (+0000)
Subject: add function to read a password
X-Git-Url: https://pd.if.org/git/?p=zpackage;a=commitdiff_plain;h=4dacea20740488a8add61a950be0e14162051a34

add function to read a password
---

diff --git a/lib/readpass.c b/lib/readpass.c
new file mode 100644
index 0000000..e48cbf3
--- /dev/null
+++ b/lib/readpass.c
@@ -0,0 +1,67 @@
+#define _POSIX_C_SOURCE 200809L
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <termios.h>
+
+char *readpass(char *prompt) {
+	FILE *term;
+	struct termios saved, noecho;
+	char *termpath, *pass = 0;;
+	int fd;
+	size_t len = 0;
+	ssize_t res;
+
+	termpath = ctermid(0);
+	if (!*termpath) {
+		errno = ENOTTY;
+		return 0;
+	}
+	term = fopen(termpath, "r+");
+	if (!term) {
+		return 0;
+	}
+
+	fd = fileno(term);
+
+	if (tcgetattr(fd, &saved) != 0) {
+		return 0;
+	}
+	noecho = saved;
+	noecho.c_lflag &= ~ECHO;
+
+	if (tcsetattr(fd, TCSAFLUSH, &noecho) != 0) {
+		return 0;
+	}
+
+	if (prompt) {
+		fprintf(term, "%s", prompt);
+		fflush(term);
+	}
+
+	/* Read the password. */
+	res = getline(&pass, &len, term);
+	fprintf(term, "\n");
+	fflush(term);
+	fclose(term);
+
+	if (res == -1) {
+		free(pass);
+		return 0;
+	}
+
+	if (res == 0) {
+		/* should be impossible */
+		free(pass);
+		return 0;
+	}
+
+	pass[res-1] = 0;
+
+	/* Restore terminal. */
+	tcsetattr(fd, TCSAFLUSH, &saved);
+
+	return pass;
+}