From 690ff87c7f77eab07607798a12f9f1d5e89c0cc5 Mon Sep 17 00:00:00 2001
From: Michael Tremer <michael.tremer@ipfire.org>
Date: Fri, 8 Dec 2023 17:22:43 +0000
Subject: [PATCH] jail: Setup PTY in the master process and add it to the event
 loop

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---
 src/libpakfire/jail.c | 98 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 96 insertions(+), 2 deletions(-)

diff --git a/src/libpakfire/jail.c b/src/libpakfire/jail.c
index 6313d894..bdf3f320 100644
--- a/src/libpakfire/jail.c
+++ b/src/libpakfire/jail.c
@@ -862,12 +862,102 @@ static int pakfire_jail_epoll_add_fd(struct pakfire_jail* jail, int epollfd, int
 	return 0;
 }
 
+// PTY Forwarding
+
+static int pakfire_jail_enable_raw_mode(struct pakfire_jail* jail,
+		struct pakfire_jail_pty_stdio* stdio) {
+	struct termios raw_attrs;
+	int r;
+
+	// Fetch all attributes
+	r = tcgetattr(stdio->fd, &stdio->attrs);
+	if (r) {
+		CTX_ERROR(jail->ctx, "Could not fetch terminal attributes from fd %d: %s\n",
+			stdio->fd, strerror(errno));
+		return -errno;
+	}
+
+	// Copy all attributes
+	raw_attrs = stdio->attrs;
+
+	// Make it RAW
+	cfmakeraw(&raw_attrs);
+
+	// Restore the attributes
+	r = tcsetattr(stdio->fd, TCSANOW, &raw_attrs);
+	if (r) {
+		CTX_ERROR(jail->ctx, "Could not restore terminal attributes for fd %d: %s\n",
+			stdio->fd, strerror(errno));
+		return -errno;
+	}
+
+	return 0;
+}
+
+static void pakfire_jail_restore_attrs(struct pakfire_jail* jail,
+		const struct pakfire_jail_pty_stdio* stdio) {
+	int r;
+
+	// Restore the attributes
+	r = tcsetattr(stdio->fd, TCSANOW, &stdio->attrs);
+	if (r) {
+		CTX_DEBUG(jail->ctx, "Could not restore terminal attributes for %d, ignoring: %s\n",
+			stdio->fd, strerror(errno));
+	}
+}
+
 static int pakfire_jail_setup_pty_forwarding(struct pakfire_jail* jail,
 		struct pakfire_jail_exec* ctx, const int epollfd, const int fd) {
+	struct winsize size;
+	int r;
+
+	CTX_DEBUG(jail->ctx, "Setting up PTY forwarding on fd %d\n", fd);
+
 	// Store the file descriptor
-	ctx->consolefd = fd;
+	ctx->pty.master.fd = fd;
 
-	// XXX TODO
+	// Configure stdin/stdout
+	ctx->pty.stdin.fd  = STDIN_FILENO;
+	ctx->pty.stdout.fd = STDOUT_FILENO;
+
+	// Fetch dimensions
+	r = ioctl(ctx->pty.stdout.fd, TIOCGWINSZ, &size);
+	if (r) {
+		CTX_ERROR(jail->ctx, "Failed to determine terminal dimensions: %s\n", strerror(errno));
+		return -errno;
+	}
+
+	// Set dimensions
+	r = ioctl(ctx->pty.master.fd, TIOCSWINSZ, &size);
+	if (r) {
+		CTX_ERROR(jail->ctx, "Failed setting dimensions: %s\n", strerror(errno));
+		return -errno;
+	}
+
+	// Enable RAW mode on standard input
+	r = pakfire_jail_enable_raw_mode(jail, &ctx->pty.stdin);
+	if (r)
+		return r;
+
+	// Enable RAW mode on standard output
+	r = pakfire_jail_enable_raw_mode(jail, &ctx->pty.stdout);
+	if (r)
+		return r;
+
+	// Add the master to the event loop
+	r = pakfire_jail_epoll_add_fd(jail, epollfd, ctx->pty.master.fd, EPOLLIN|EPOLLOUT|EPOLLET);
+	if (r)
+		return r;
+
+	// Add standard input to the event loop
+	r = pakfire_jail_epoll_add_fd(jail, epollfd, ctx->pty.stdin.fd, EPOLLIN|EPOLLET);
+	if (r)
+		return r;
+
+	// Add standard output to the event loop
+	r = pakfire_jail_epoll_add_fd(jail, epollfd, ctx->pty.stdout.fd, EPOLLOUT|EPOLLET);
+	if (r)
+		return r;
 
 	return 0;
 }
@@ -1129,6 +1219,10 @@ ERROR:
 	if (timerfd >= 0)
 		close(timerfd);
 
+	// Restore any changed terminal attributes
+	pakfire_jail_restore_attrs(jail, &ctx->pty.stdin);
+	pakfire_jail_restore_attrs(jail, &ctx->pty.stdout);
+
 	return r;
 }
 
-- 
2.39.2