From 2e0ed48470f51d2f7a55baed1d6050f7a2bcf38e Mon Sep 17 00:00:00 2001
From: Daniel Lehman <dlehman@esri.com>
Date: Tue, 29 Oct 2019 09:46:31 -0700
Subject: [PATCH] msvcrt: Set errno in _lseeki64.

Signed-off-by: Daniel Lehman <dlehman@esri.com>
---
 dlls/msvcrt/file.c       |  1 +
 dlls/msvcrt/tests/file.c | 26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/dlls/msvcrt/file.c b/dlls/msvcrt/file.c
index 9075b432ff..825d442bfa 100644
--- a/dlls/msvcrt/file.c
+++ b/dlls/msvcrt/file.c
@@ -1265,6 +1265,7 @@ __int64 CDECL MSVCRT__lseeki64(int fd, __int64 offset, int whence)
 
   if (info->handle == INVALID_HANDLE_VALUE)
   {
+    *MSVCRT__errno() = MSVCRT_EBADF;
     release_ioinfo(info);
     return -1;
   }
diff --git a/dlls/msvcrt/tests/file.c b/dlls/msvcrt/tests/file.c
index 0ed59e347e..97d81abd00 100644
--- a/dlls/msvcrt/tests/file.c
+++ b/dlls/msvcrt/tests/file.c
@@ -2583,6 +2583,31 @@ static void test__creat(void)
         p__set_fmode(old_fmode);
 }
 
+static void test_lseek(void)
+{
+    int fd;
+    char testdata[4] = {'a', '\n', 'b', '\n'};
+
+    errno = 0xdeadbeef;
+    ok(_lseek(-42, 0, SEEK_SET) == -1, "expected failure\n");
+    ok(errno == EBADF, "errno = %d\n", errno);
+
+    fd = _creat("_creat.tst", _S_IWRITE);
+    ok(fd > 0, "_creat failed\n");
+    _write(fd, testdata, 4);
+
+    errno = 0xdeadbeef;
+    ok(_lseek(fd, 0, 42) == -1, "expected failure\n");
+    ok(errno == EINVAL, "errno = %d\n", errno);
+
+    errno = 0xdeadbeef;
+    ok(_lseek(fd, -42, SEEK_SET) == -1, "expected failure\n");
+    ok(errno == EINVAL, "errno = %d\n", errno);
+
+    _close(fd);
+    DeleteFileA("_creat.tst");
+}
+
 START_TEST(file)
 {
     int arg_c;
@@ -2654,6 +2679,7 @@ START_TEST(file)
     test_write_flush();
     test_close();
     test__creat();
+    test_lseek();
 
     /* Wait for the (_P_NOWAIT) spawned processes to finish to make sure the report
      * file contains lines in the correct order
-- 
2.17.0