path: root/libio/freopen64.c
diff options
authorAdhemerval Zanella <adhemerval.zanella@linaro.org>2017-07-13 16:43:24 -0300
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2018-10-02 10:01:56 -0300
commit0b727ed4d605d9318cb0d323c88abb0d5a441a9b (patch)
tree456efbab739f291b486ee8d937703cb0d4db5cef /libio/freopen64.c
parentd0e91e8c4ef77997c940538eaa752799c9dda2d3 (diff)
libio: Flush stream at freopen (BZ#21037)
As POSIX states [1] a freopen call should first flush the stream as if by a call fflush. C99 (n1256) and C11 (n1570) only states the function should first close any file associated with the specific stream. Although current implementation only follow C specification, current BSD and other libc implementation (musl) are in sync with POSIX and fflush the stream. This patch change freopen{64} to fflush the stream before actually reopening it (or returning if the stream does not support reopen). It also changes the Linux implementation to avoid a dynamic allocation on 'fd_to_filename'. Checked on x86_64-linux-gnu. [BZ #21037] * libio/Makefile (tests): Add tst-memstream4 and tst-wmemstream4. * libio/freopen.c (freopen): Sync stream before reopen and adjust to new fd_to_filename interface. * libio/freopen64.c (freopen64): Likewise. * libio/tst-memstream.h: New file. * libio/tst-memstream4.c: Likewise. * libio/tst-wmemstream4.c: Likewise. * sysdeps/generic/fd_to_filename.h (fd_to_filename): Change signature. * sysdeps/unix/sysv/linux/fd_to_filename.h (fd_to_filename): Likewise and remove internal dynamic allocation. [1] http://pubs.opengroup.org/onlinepubs/9699919799/
Diffstat (limited to 'libio/freopen64.c')
1 files changed, 15 insertions, 11 deletions
diff --git a/libio/freopen64.c b/libio/freopen64.c
index ea7ebd3da48..055b999e597 100644
--- a/libio/freopen64.c
+++ b/libio/freopen64.c
@@ -24,27 +24,33 @@
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 <libioP.h>
#include <fd_to_filename.h>
-#include <kernel-features.h>
freopen64 (const char *filename, const char *mode, FILE *fp)
- FILE *result;
+ FILE *result = NULL;
+ char fdfilename[FD_TO_FILENAME_SIZE];
- 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;
_IO_file_close_it (fp);
_IO_JUMPS_FILE_plus (fp) = &_IO_file_jumps;
@@ -84,8 +90,6 @@ freopen64 (const char *filename, const char *mode, FILE *fp)
__close (fd);
- if (filename == NULL)
- free ((char *) gfilename);
_IO_release_lock (fp);
return result;