From 32c08bc6418674f7e3330d4b980a25b1ce53c903 Mon Sep 17 00:00:00 2001
From: Radon Rosborough <radon.neon@gmail.com>
Date: Mon, 9 Aug 2021 21:31:27 -0700
Subject: [PATCH] Initial version of riju-pty wrapper

---
 system/src/riju-pty.c | 79 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 system/src/riju-pty.c

diff --git a/system/src/riju-pty.c b/system/src/riju-pty.c
new file mode 100644
index 0000000..70f16fc
--- /dev/null
+++ b/system/src/riju-pty.c
@@ -0,0 +1,79 @@
+#define _GNU_SOURCE
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+void __attribute__((noreturn)) die(char *msg)
+{
+  fprintf(stderr, "%s\n", msg);
+  exit(1);
+}
+
+void die_with_usage() { die("usage: riju-pty CMDLINE..."); }
+
+int main(int argc, char **argv)
+{
+  if (argc <= 1)
+    die_with_usage();
+  int pty_master_fd = posix_openpt(O_RDWR);
+  if (pty_master_fd < 0)
+    die("posix_openpt failed");
+  if (grantpt(pty_master_fd) < 0)
+    die("grantpt failed");
+  if (unlockpt(pty_master_fd) < 0)
+    die("unlockpt failed");
+  char *pty_slave_name = ptsname(pty_master_fd);
+  if (pty_slave_name == NULL)
+    die("ptsname failed");
+  pid_t pid = fork();
+  if (pid < 0)
+    die("fork failed");
+  else if (pid == 0) {
+    close(pty_master_fd);
+    int pty_slave_fd = open(pty_slave_name, O_RDWR);
+    if (pty_slave_fd < 0)
+      die("open failed");
+    if (dup2(pty_slave_fd, STDIN_FILENO) < 0)
+      die("dup2 failed");
+    if (dup2(pty_slave_fd, STDOUT_FILENO) < 0)
+      die("dup2 failed");
+    if (dup2(pty_slave_fd, STDERR_FILENO) < 0)
+      die("dup2 failed");
+    if (close(pty_slave_fd) < 0)
+      die("close failed");
+    execvp(argv[1], &argv[1]);
+    die("execvp failed");
+  }
+  char buf[1024];
+  int len, len_written;
+  pid = fork();
+  if (pid < 0)
+    die("fork failed");
+  else if (pid == 0) {
+    while ((len = read(STDIN_FILENO, buf, 1024)) > 0) {
+      char *ptr = buf;
+      while (len > 0) {
+        len_written = write(pty_master_fd, ptr, len);
+        if (len_written < 0)
+          die("write failed");
+        len -= len_written;
+        ptr += len_written;
+      }
+    }
+  } else {
+    if (setvbuf(stdout, NULL, _IONBF, 0) != 0)
+      die("setvbuf failed");
+    while ((len = read(pty_master_fd, buf, 1024)) > 0) {
+      fwrite(buf, 1, len, stdout);
+      if (ferror(stdout))
+        die("fwrite failed");
+      if (feof(stdout))
+        break;
+    }
+  }
+  return 0;
+}