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[thirdparty/glibc.git] / libio / freopen.c

diff --git a/libio/freopen.c b/libio/freopen.c
index 91cde193ee3cbe8ef4ab9fcfff96d4a15b7e3dd3..e30f7caf3d1d792fdc23d713c273d858c05cfea1 100644 (file)
--- a/libio/freopen.c
+++ b/libio/freopen.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1993-2015 Free Software Foundation, Inc.
+/* Copyright (C) 1993-2019 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -13,7 +13,7 @@
 
    You should have received a copy of the GNU Lesser General Public
    License along with the GNU C Library; if not, see
-   <http://www.gnu.org/licenses/>.
+   <https://www.gnu.org/licenses/>.
 
    As a special exception, if you link the code in this file with
    files compiled with a GNU compiler to produce an executable,
@@ -24,31 +24,34 @@
    This exception applies to code released by its copyright holders
    in files containing the exception.  */
 
-#include "libioP.h"
-#include "stdio.h"
+#include <stdio.h>
 #include <fcntl.h>
 #include <stdlib.h>
 #include <unistd.h>
 
-#include <shlib-compat.h>
+#include <libioP.h>
 #include <fd_to_filename.h>
+#include <shlib-compat.h>
 
-#include <kernel-features.h>
-
-FILE*
-freopen (filename, mode, fp)
-     const char* filename;
-     const char* mode;
-     FILE* fp;
+FILE *
+freopen (const char *filename, const char *mode, FILE *fp)
 {
-  FILE *result;
+  FILE *result = NULL;
+  char fdfilename[FD_TO_FILENAME_SIZE];
+
   CHECK_FILE (fp, NULL);
-  if (!(fp->_flags & _IO_IS_FILEBUF))
-    return NULL;
+
   _IO_acquire_lock (fp);
+  /* First flush the stream (failure should be ignored).  */
+  _IO_SYNC (fp);
+
+  if (!(fp->_flags & _IO_IS_FILEBUF))
+    goto end;
+
   int fd = _IO_fileno (fp);
-  const char *gfilename = (filename == NULL && fd >= 0
-                          ? fd_to_filename (fd) : filename);
+  const char *gfilename
+    = filename != NULL ? filename : fd_to_filename (fd, fdfilename);
+
   fp->_flags2 |= _IO_FLAGS2_NOCLOSE;
 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
   if (&_IO_stdin_used == NULL)
@@ -59,14 +62,14 @@ freopen (filename, mode, fp)
         to the old libio may be passed into shared C library and wind
         up here. */
       _IO_old_file_close_it (fp);
-      _IO_JUMPS ((struct _IO_FILE_plus *) fp) = &_IO_old_file_jumps;
+      _IO_JUMPS_FUNC_UPDATE (fp, &_IO_old_file_jumps);
       result = _IO_old_file_fopen (fp, gfilename, mode);
     }
   else
 #endif
     {
       _IO_file_close_it (fp);
-      _IO_JUMPS ((struct _IO_FILE_plus *) fp) = &_IO_file_jumps;
+      _IO_JUMPS_FILE_plus (fp) = &_IO_file_jumps;
       if (_IO_vtable_offset (fp) == 0 && fp->_wide_data != NULL)
        fp->_wide_data->_wide_vtable = &_IO_wfile_jumps;
       result = _IO_file_fopen (fp, gfilename, mode, 1);
@@ -79,43 +82,31 @@ freopen (filename, mode, fp)
       /* unbound stream orientation */
       result->_mode = 0;
 
-      if (fd != -1)
+      if (fd != -1 && _IO_fileno (result) != fd)
        {
-#ifdef O_CLOEXEC
-# ifndef __ASSUME_DUP3
-         int newfd;
-         if (__have_dup3 < 0)
-           newfd = -1;
-         else
-           newfd =
-# endif
-             __dup3 (_IO_fileno (result), fd,
-                      (result->_flags2 & _IO_FLAGS2_CLOEXEC) != 0
-                      ? O_CLOEXEC : 0);
-#else
-# define newfd 1
-#endif
-
-#ifndef __ASSUME_DUP3
-         if (newfd < 0)
+         /* At this point we have both file descriptors already allocated,
+            so __dup3 will not fail with EBADF, EINVAL, or EMFILE.  But
+            we still need to check for EINVAL and, due Linux internal
+            implementation, EBUSY.  It is because on how it internally opens
+            the file by splitting the buffer allocation operation and VFS
+            opening (a dup operation may run when a file is still pending
+            'install' on VFS).  */
+         if (__dup3 (_IO_fileno (result), fd,
+                     (result->_flags2 & _IO_FLAGS2_CLOEXEC) != 0
+                     ? O_CLOEXEC : 0) == -1)
            {
-             if (errno == ENOSYS)
-               __have_dup3 = -1;
-
-             __dup2 (_IO_fileno (result), fd);
-             if ((result->_flags2 & _IO_FLAGS2_CLOEXEC) != 0)
-               __fcntl (fd, F_SETFD, FD_CLOEXEC);
+             _IO_file_close_it (result);
+             result = NULL;
+             goto end;
            }
-#endif
          __close (_IO_fileno (result));
          _IO_fileno (result) = fd;
        }
     }
   else if (fd != -1)
     __close (fd);
-  if (filename == NULL)
-    free ((char *) gfilename);
 
+end:
   _IO_release_lock (fp);
   return result;
 }