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

diff --git a/libio/freopen.c b/libio/freopen.c
index cae9d307cd0a7d52935f8a75405e569a0eecf304..e30f7caf3d1d792fdc23d713c273d858c05cfea1 100644 (file)
--- a/libio/freopen.c
+++ b/libio/freopen.c
@@ -1,5 +1,4 @@
-/* Copyright (C) 1993,95,96,97,98,2000,2001,2002,2003
-       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
@@ -13,9 +12,8 @@
    Lesser General Public License for more details.
 
    You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, write to the Free
-   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
-   02111-1307 USA.
+   License along with the GNU C Library; if not, see
+   <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,
@@ -26,32 +24,35 @@
    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>
 
-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;
-  int fd = -1;
+  FILE *result = NULL;
+  char fdfilename[FD_TO_FILENAME_SIZE];
+
   CHECK_FILE (fp, NULL);
+
+  _IO_acquire_lock (fp);
+  /* First flush the stream (failure should be ignored).  */
+  _IO_SYNC (fp);
+
   if (!(fp->_flags & _IO_IS_FILEBUF))
-    return NULL;
-  _IO_cleanup_region_start ((void (*) __P ((void *))) _IO_funlockfile, fp);
-  _IO_flockfile (fp);
-  if (filename == NULL && _IO_fileno (fp) >= 0)
-    {
-      fd = __dup (_IO_fileno (fp));
-      if (fd != -1)
-       filename = fd_to_filename (fd);
-    }
+    goto end;
+
+  int fd = _IO_fileno (fp);
+  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)
     {
@@ -61,30 +62,51 @@ 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;
-      result = _IO_old_file_fopen (fp, filename, mode);
+      _IO_JUMPS_FUNC_UPDATE (fp, &_IO_old_file_jumps);
+      result = _IO_old_file_fopen (fp, gfilename, mode);
     }
   else
 #endif
     {
-      INTUSE(_IO_file_close_it) (fp);
-      _IO_JUMPS ((struct _IO_FILE_plus *) fp) = &_IO_file_jumps;
+      _IO_file_close_it (fp);
+      _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 = INTUSE(_IO_file_fopen) (fp, filename, mode, 1);
+      result = _IO_file_fopen (fp, gfilename, mode, 1);
       if (result != NULL)
        result = __fopen_maybe_mmap (result);
     }
+  fp->_flags2 &= ~_IO_FLAGS2_NOCLOSE;
   if (result != NULL)
-    /* unbound stream orientation */
-    result->_mode = 0;
-  if (fd != -1)
     {
-      __close (fd);
-      if (filename != NULL)
-       free ((char *) filename);
+      /* unbound stream orientation */
+      result->_mode = 0;
+
+      if (fd != -1 && _IO_fileno (result) != fd)
+       {
+         /* 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)
+           {
+             _IO_file_close_it (result);
+             result = NULL;
+             goto end;
+           }
+         __close (_IO_fileno (result));
+         _IO_fileno (result) = fd;
+       }
     }
-  _IO_funlockfile (fp);
-  _IO_cleanup_region_end (0);
+  else if (fd != -1)
+    __close (fd);
+
+end:
+  _IO_release_lock (fp);
   return result;
 }