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Add missing glibc-rh1078355.patch

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Siddhesh Poyarekar 2014-03-19 22:49:13 +05:30
parent b7b25cd2fa
commit f6119bbf97
1 changed files with 259 additions and 0 deletions
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commit e4018856ea36b00fbd580420f061b10444587661
Author: Siddhesh Poyarekar <siddhesh@redhat.com>
Date: Wed Mar 19 00:42:30 2014 +0530
Fix offset computation for append+ mode on switching from read (BZ #16724)
The offset computation in write mode uses the fact that _IO_read_end
is kept in sync with the external file offset. This however is not
true when O_APPEND is in effect since switching to write mode ought to
send the external file offset to the end of file without making the
necessary adjustment to _IO_read_end.
Hence in append mode, offset computation when writing should only
consider the effect of unflushed writes, i.e. from _IO_write_base to
_IO_write_ptr.
diff --git a/libio/Makefile b/libio/Makefile
index 69c25c0..4bedfad 100644
--- a/libio/Makefile
+++ b/libio/Makefile
@@ -60,7 +60,8 @@ tests = tst_swprintf tst_wprintf tst_swscanf tst_wscanf tst_getwc tst_putwc \
tst-wmemstream1 tst-wmemstream2 \
bug-memstream1 bug-wmemstream1 \
tst-setvbuf1 tst-popen1 tst-fgetwc bug-wsetpos tst-fseek \
- tst-fwrite-error tst-ftell-partial-wide tst-ftell-active-handler
+ tst-fwrite-error tst-ftell-partial-wide tst-ftell-active-handler \
+ tst-ftell-append
ifeq (yes,$(build-shared))
# Add test-fopenloc only if shared library is enabled since it depends on
# shared localedata objects.
diff --git a/libio/fileops.c b/libio/fileops.c
index cf68dbf..204cfea 100644
--- a/libio/fileops.c
+++ b/libio/fileops.c
@@ -91,7 +91,9 @@ extern struct __gconv_trans_data __libio_translit attribute_hidden;
The position in the buffer that corresponds to the position
in external file system is normally _IO_read_end, except in putback
- mode, when it is _IO_save_end.
+ mode, when it is _IO_save_end and also when the file is in append mode,
+ since switching from read to write mode automatically sends the position in
+ the external file system to the end of file.
If the field _fb._offset is >= 0, it gives the offset in
the file as a whole corresponding to eGptr(). (?)
@@ -966,6 +968,14 @@ do_ftell (_IO_FILE *fp)
/* Adjust for unflushed data. */
if (!was_writing)
offset -= fp->_IO_read_end - fp->_IO_read_ptr;
+ /* We don't trust _IO_read_end to represent the current file offset when
+ writing in append mode because the value would have to be shifted to
+ the end of the file during a flush. Use the write base instead, along
+ with the new offset we got above when we did a seek to the end of the
+ file. */
+ else if (append_mode)
+ offset += fp->_IO_write_ptr - fp->_IO_write_base;
+ /* For all other modes, _IO_read_end represents the file offset. */
else
offset += fp->_IO_write_ptr - fp->_IO_read_end;
}
diff --git a/libio/tst-ftell-append.c b/libio/tst-ftell-append.c
new file mode 100644
index 0000000..604dc03
--- /dev/null
+++ b/libio/tst-ftell-append.c
@@ -0,0 +1,169 @@
+/* Verify that ftell returns the correct value after a read and a write on a
+ file opened in a+ mode.
+ Copyright (C) 2014 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
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ 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, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <locale.h>
+#include <wchar.h>
+
+/* data points to either char_data or wide_data, depending on whether we're
+ testing regular file mode or wide mode respectively. Similarly,
+ fputs_func points to either fputs or fputws. data_len keeps track of the
+ length of the current data and file_len maintains the current file
+ length. */
+#define BUF_LEN 4
+static void *buf;
+static char char_buf[BUF_LEN];
+static wchar_t wide_buf[BUF_LEN];
+static const void *data;
+static const char *char_data = "abcdefghijklmnopqrstuvwxyz";
+static const wchar_t *wide_data = L"abcdefghijklmnopqrstuvwxyz";
+static size_t data_len;
+static size_t file_len;
+
+typedef int (*fputs_func_t) (const void *data, FILE *fp);
+fputs_func_t fputs_func;
+
+typedef void *(*fgets_func_t) (void *s, int size, FILE *stream);
+fgets_func_t fgets_func;
+
+static int do_test (void);
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
+
+static FILE *
+init_file (const char *filename)
+{
+ FILE *fp = fopen (filename, "w");
+ if (fp == NULL)
+ {
+ printf ("fopen: %m\n");
+ return NULL;
+ }
+
+ int written = fputs_func (data, fp);
+
+ if (written == EOF)
+ {
+ printf ("fputs failed to write data\n");
+ fclose (fp);
+ return NULL;
+ }
+
+ file_len = data_len;
+
+ fclose (fp);
+
+ fp = fopen (filename, "a+");
+ if (fp == NULL)
+ {
+ printf ("fopen(a+): %m\n");
+ return NULL;
+ }
+
+ return fp;
+}
+
+static int
+do_one_test (const char *filename)
+{
+ FILE *fp = init_file (filename);
+
+ if (fp == NULL)
+ return 1;
+
+ void *ret = fgets_func (buf, BUF_LEN, fp);
+
+ if (ret == NULL)
+ {
+ printf ("read failed: %m\n");
+ fclose (fp);
+ return 1;
+ }
+
+ int written = fputs_func (data, fp);
+
+ if (written == EOF)
+ {
+ printf ("fputs failed to write data\n");
+ fclose (fp);
+ return 1;
+ }
+
+ file_len += data_len;
+
+ long off = ftell (fp);
+
+ if (off != file_len)
+ {
+ printf ("Incorrect offset %ld, expected %zu\n", off, file_len);
+ fclose (fp);
+ return 1;
+ }
+ else
+ printf ("Correct offset %ld after write.\n", off);
+
+ return 0;
+}
+
+/* Run the tests for regular files and wide mode files. */
+static int
+do_test (void)
+{
+ int ret = 0;
+ char *filename;
+ int fd = create_temp_file ("tst-ftell-append-tmp.", &filename);
+
+ if (fd == -1)
+ {
+ printf ("create_temp_file: %m\n");
+ return 1;
+ }
+
+ close (fd);
+
+ /* Tests for regular files. */
+ puts ("Regular mode:");
+ fputs_func = (fputs_func_t) fputs;
+ fgets_func = (fgets_func_t) fgets;
+ data = char_data;
+ buf = char_buf;
+ data_len = strlen (char_data);
+ ret |= do_one_test (filename);
+
+ /* Tests for wide files. */
+ puts ("Wide mode:");
+ if (setlocale (LC_ALL, "en_US.UTF-8") == NULL)
+ {
+ printf ("Cannot set en_US.UTF-8 locale.\n");
+ return 1;
+ }
+ fputs_func = (fputs_func_t) fputws;
+ fgets_func = (fgets_func_t) fgetws;
+ data = wide_data;
+ buf = wide_buf;
+ data_len = wcslen (wide_data);
+ ret |= do_one_test (filename);
+
+ return ret;
+}
diff --git a/libio/wfileops.c b/libio/wfileops.c
index 3199861..f123add 100644
--- a/libio/wfileops.c
+++ b/libio/wfileops.c
@@ -713,9 +713,16 @@ do_ftell_wide (_IO_FILE *fp)
offset += outstop - out;
}
- /* _IO_read_end coincides with fp._offset, so the actual file
- position is fp._offset - (_IO_read_end - new_write_ptr). */
- offset -= fp->_IO_read_end - fp->_IO_write_ptr;
+ /* We don't trust _IO_read_end to represent the current file offset
+ when writing in append mode because the value would have to be
+ shifted to the end of the file during a flush. Use the write base
+ instead, along with the new offset we got above when we did a seek
+ to the end of the file. */
+ if (append_mode)
+ offset += fp->_IO_write_ptr - fp->_IO_write_base;
+ /* For all other modes, _IO_read_end represents the file offset. */
+ else
+ offset += fp->_IO_write_ptr - fp->_IO_read_end;
}
}