From 9ce20a62a4dd5d929830aea5b99b8d851c2cd75c Mon Sep 17 00:00:00 2001
From: sw1tchbl4d3 <sw1tchbl4d3@sw1tchbl4d3.com>
Date: Sat, 17 Dec 2022 00:12:03 +0100
Subject: [PATCH] Simplify tty finding process in readpassphrase

This went through a bunch of hoops before to acquire a file descriptor
we already had, this is now ommited.
---
 readpassphrase.h | 25 ++++---------------------
 1 file changed, 4 insertions(+), 21 deletions(-)

diff --git a/readpassphrase.h b/readpassphrase.h
index 94a63d9..7a7011b 100644
--- a/readpassphrase.h
+++ b/readpassphrase.h
@@ -4,8 +4,6 @@
 #include <fcntl.h>
 
 char* readpassphrase(const char* prompt, char* buf, size_t bufsz) {
-    char stdin_path[256];
-    char tty_link_path[256];
     int n;
     int ttyfd = -1;
 
@@ -21,42 +19,27 @@ char* readpassphrase(const char* prompt, char* buf, size_t bufsz) {
     if (ttyfd < 0)
         return NULL;
 
-    snprintf(tty_link_path, sizeof(tty_link_path), "/proc/self/fd/%d", ttyfd);
-
-    n = readlink(tty_link_path, stdin_path, sizeof(stdin_path));
-    if (n < 0)
-        return NULL;
-    
-    stdin_path[n] = '\0';
-
-    int fd = open(stdin_path, O_RDWR);
-    if (fd < 0)
-        return NULL;
-
     term.c_lflag &= ~ECHO;
     tcsetattr(ttyfd, 0, &term);
     term.c_lflag |= ECHO;
 
-    if (write(fd, prompt, strlen(prompt)) < 0) {
+    if (write(ttyfd, prompt, strlen(prompt)) < 0) {
         tcsetattr(ttyfd, 0, &term);
-        close(fd);
         return NULL;
     }
 
-    n = read(fd, buf, bufsz);
+    n = read(ttyfd, buf, bufsz);
     if (n < 0) {
         tcsetattr(ttyfd, 0, &term);
-        n = write(fd, "\n", 1);
-        close(fd);
+        n = write(ttyfd, "\n", 1);
         return NULL;
     }
 
     buf[n-1] = '\0';
 
     // NOTE: As we disabled echo, the enter sent by the user isn't displayed, so we resend it.
-    n = write(fd, "\n", 1);
+    n = write(ttyfd, "\n", 1);
 
-    close(fd);
     tcsetattr(ttyfd, 0, &term);
 
     return buf;