From f4afed90e605074e86900da9e9ee065cec91aa5b Mon Sep 17 00:00:00 2001
From: Simon McVittie <smcv@collabora.com>
Date: Mon, 5 Feb 2024 20:29:47 +0000
Subject: [PATCH] tests: Exercise g_fdwalk_set_cloexec() and g_closefrom()

Signed-off-by: Simon McVittie <smcv@collabora.com>
---
 glib/tests/unix.c | 184 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 184 insertions(+)

diff --git a/glib/tests/unix.c b/glib/tests/unix.c
index e4003f730..8f624c527 100644
--- a/glib/tests/unix.c
+++ b/glib/tests/unix.c
@@ -36,6 +36,187 @@
 
 #include "testutils.h"
 
+static void
+async_signal_safe_message (const char *message)
+{
+  if (write (2, message, strlen (message)) < 0 ||
+      write (2, "\n", 1) < 0)
+    {
+      /* ignore: not much we can do */
+    }
+}
+
+static void
+test_closefrom (void)
+{
+  /* Enough file descriptors to be confident that we're operating on
+   * all of them */
+  const int N_FDS = 20;
+  int *fds;
+  int fd;
+  int i;
+  pid_t child;
+  int wait_status;
+
+  /* The loop that populates @fds with pipes assumes this */
+  g_assert (N_FDS % 2 == 0);
+
+  g_test_summary ("Test g_closefrom(), g_fdwalk_set_cloexec()");
+  g_test_bug ("https://gitlab.gnome.org/GNOME/glib/-/issues/3247");
+
+  for (fd = 0; fd <= 2; fd++)
+    {
+      int flags;
+
+      g_assert_no_errno ((flags = fcntl (fd, F_GETFD)));
+      g_assert_no_errno (fcntl (fd, F_SETFD, flags & ~FD_CLOEXEC));
+    }
+
+  fds = g_new0 (int, N_FDS);
+
+  for (i = 0; i < N_FDS; i += 2)
+    {
+      GError *error = NULL;
+      int pipefd[2];
+      int res;
+
+      /* Intentionally neither O_CLOEXEC nor FD_CLOEXEC */
+      res = g_unix_open_pipe (pipefd, 0, &error);
+      g_assert (res);
+      g_assert_no_error (error);
+      g_clear_error (&error);
+      fds[i] = pipefd[0];
+      fds[i + 1] = pipefd[1];
+    }
+
+  child = fork ();
+
+  /* Child process exits with status = 100 + the first wrong fd,
+   * or 0 if all were correct */
+  if (child == 0)
+    {
+      for (i = 0; i < N_FDS; i++)
+        {
+          int flags = fcntl (fds[i], F_GETFD);
+
+          if (flags == -1)
+            {
+              async_signal_safe_message ("fd should not have been closed");
+              _exit (100 + fds[i]);
+            }
+
+          if (flags & FD_CLOEXEC)
+            {
+              async_signal_safe_message ("fd should not have been close-on-exec yet");
+              _exit (100 + fds[i]);
+            }
+        }
+
+      g_fdwalk_set_cloexec (3);
+
+      for (i = 0; i < N_FDS; i++)
+        {
+          int flags = fcntl (fds[i], F_GETFD);
+
+          if (flags == -1)
+            {
+              async_signal_safe_message ("fd should not have been closed");
+              _exit (100 + fds[i]);
+            }
+
+          if (!(flags & FD_CLOEXEC))
+            {
+              async_signal_safe_message ("fd should have been close-on-exec");
+              _exit (100 + fds[i]);
+            }
+        }
+
+      g_closefrom (3);
+
+      for (fd = 0; fd <= 2; fd++)
+        {
+          int flags = fcntl (fd, F_GETFD);
+
+          if (flags == -1)
+            {
+              async_signal_safe_message ("fd should not have been closed");
+              _exit (100 + fd);
+            }
+
+          if (flags & FD_CLOEXEC)
+            {
+              async_signal_safe_message ("fd should not have been close-on-exec");
+              _exit (100 + fd);
+            }
+        }
+
+      for (i = 0; i < N_FDS; i++)
+        {
+          if (fcntl (fds[i], F_GETFD) != -1 || errno != EBADF)
+            {
+              async_signal_safe_message ("fd should have been closed");
+              _exit (100 + fds[i]);
+            }
+        }
+
+      _exit (0);
+    }
+
+  g_assert_no_errno (waitpid (child, &wait_status, 0));
+
+  if (WIFEXITED (wait_status))
+    {
+      int exit_status = WEXITSTATUS (wait_status);
+
+      if (exit_status != 0)
+        g_test_fail_printf ("File descriptor %d in incorrect state", exit_status - 100);
+    }
+  else
+    {
+      g_test_fail_printf ("Unexpected wait status %d", wait_status);
+    }
+
+  for (i = 0; i < N_FDS; i++)
+    {
+      GError *error = NULL;
+
+      g_close (fds[i], &error);
+      g_assert_no_error (error);
+      g_clear_error (&error);
+    }
+
+  g_free (fds);
+
+  if (g_test_undefined ())
+    {
+      g_test_trap_subprocess ("/glib-unix/closefrom/subprocess/einval",
+                              0, G_TEST_SUBPROCESS_DEFAULT);
+      g_test_trap_assert_passed ();
+    }
+}
+
+static void
+test_closefrom_subprocess_einval (void)
+{
+  int res;
+  int errsv;
+
+  g_log_set_always_fatal (G_LOG_FATAL_MASK);
+  g_log_set_fatal_mask ("GLib", G_LOG_FATAL_MASK);
+
+  errno = 0;
+  res = g_closefrom (-1);
+  errsv = errno;
+  g_assert_cmpint (res, ==, -1);
+  g_assert_cmpint (errsv, ==, EINVAL);
+
+  errno = 0;
+  res = g_fdwalk_set_cloexec (-42);
+  errsv = errno;
+  g_assert_cmpint (res, ==, -1);
+  g_assert_cmpint (errsv, ==, EINVAL);
+}
+
 static void
 test_pipe (void)
 {
@@ -613,6 +794,9 @@ main (int   argc,
 {
   g_test_init (&argc, &argv, NULL);
 
+  g_test_add_func ("/glib-unix/closefrom", test_closefrom);
+  g_test_add_func ("/glib-unix/closefrom/subprocess/einval",
+                   test_closefrom_subprocess_einval);
   g_test_add_func ("/glib-unix/pipe", test_pipe);
   g_test_add_func ("/glib-unix/pipe/fd-cloexec", test_pipe_fd_cloexec);
   g_test_add_func ("/glib-unix/pipe-stdio-overwrite", test_pipe_stdio_overwrite);