From 3349e674c3ee0c3c8bc063b2c3ab7af636949eda Mon Sep 17 00:00:00 2001
From: Tobias Ulmer <tu@emlix.com>
Date: Tue, 12 Feb 2019 19:06:05 +0100
Subject: [PATCH] e2lib: implement forkpty

Signed-off-by: Tobias Ulmer <tu@emlix.com>
---
 generic/e2lib.lua | 24 ++++++++++++++++++++++++
 generic/le2lib.c  | 25 +++++++++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/generic/e2lib.lua b/generic/e2lib.lua
index 9823787..aec3579 100644
--- a/generic/e2lib.lua
+++ b/generic/e2lib.lua
@@ -294,6 +294,30 @@ function e2lib.fork()
     return pid
 end
 
+--- Forkpty. Like fork but open a PTY.
+-- @return PID of child or false on error. PID of 0 means child process.
+-- @return File Descriptor for pseudo terminal (parent only).
+--         Error object on failure.
+-- @return Path to PTY device node.
+function e2lib.forkpty()
+    local rc, re
+    local pid, fdm, ptyname
+
+    pid, fdm, ptyname = le2lib.forkpty()
+    if not pid then
+        return false, err.new("failed to fork new pty: %s", fdm)
+    end
+    if pid == 0 then
+        -- child, return early
+        return pid
+    end
+
+    assert(type(fdm) == "number")
+    assert(type(ptyname) == "string")
+
+    return pid, fdm, ptyname
+end
+
 --- Set umask value.
 -- @param mask New umask value.
 -- @return Previous umask value.
diff --git a/generic/le2lib.c b/generic/le2lib.c
index e5b0b7e..bac7f73 100644
--- a/generic/le2lib.c
+++ b/generic/le2lib.c
@@ -33,6 +33,7 @@
 #include <poll.h>
 #include <fcntl.h>
 #include <ctype.h>
+#include <pty.h>
 
 #include <lua.h>
 #include <lualib.h>
@@ -884,6 +885,29 @@ signal_received(lua_State *L)
 	return 2;
 }
 
+static int
+do_forkpty(lua_State *L)
+{
+	int cpid, fdm;
+	char ptyname[PATH_MAX];
+
+	cpid = forkpty(&fdm, ptyname, NULL, NULL);
+	if (cpid < 0) {
+		lua_pushboolean(L, 0);
+		lua_pushstring(L, strerror(errno));
+		return 2;
+	}
+
+	lua_pushnumber(L, cpid);
+	if (cpid == 0)
+		return 1;
+
+	lua_pushnumber(L, fdm);
+	lua_pushstring(L, ptyname);
+
+	return 3;
+}
+
 static luaL_Reg lib[] = {
 	{ "chdir", change_directory },
 	{ "chmod", do_chmod },
@@ -893,6 +917,7 @@ static luaL_Reg lib[] = {
 	{ "execvp", do_execvp },
 	{ "exists", file_exists },
 	{ "fork", lua_fork },
+	{ "forkpty", do_forkpty },
 	{ "getpid", do_getpid },
 	{ "hardlink", do_hardlink },
 	{ "kill", do_kill },
-- 
2.39.5