diff --git a/libio/Makefile b/libio/Makefile
index 22dbcae..488ee51 100644
--- a/libio/Makefile
+++ b/libio/Makefile
@@ -60,7 +60,7 @@ 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-fwrite-error tst-ftell-active-handler
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 a3499be..2e7bc8d 100644
--- a/libio/fileops.c
+++ b/libio/fileops.c
@@ -929,6 +929,93 @@ _IO_file_sync_mmap (_IO_FILE *fp)
return 0;
}
+/* Get the current file offset using a system call. This is the safest method
+ to get the current file offset, since we are sure that we get the current
+ state of the file. Before the stream handle is activated (by using fread,
+ fwrite, etc.), an application may alter the state of the file descriptor
+ underlying it by calling read/write/lseek on it. Using a cached offset at
+ this point will result in returning the incorrect value. Same is the case
+ when one switches from reading in a+ mode to writing, where the buffer has
+ not been flushed - the cached offset would reflect the reading position
+ while the actual write position would be at the end of the file.
+
+ do_ftell and do_ftell_wide may resort to using the cached offset in some
+ special cases instead of calling get_file_offset, but those cases should be
+ thoroughly described. */
+_IO_off64_t
+get_file_offset (_IO_FILE *fp)
+{
+ if ((fp->_flags & _IO_IS_APPENDING) == _IO_IS_APPENDING)
+ {
+ struct stat64 st;
+ bool ret = (_IO_SYSSTAT (fp, &st) == 0 && S_ISREG (st.st_mode));
+ if (ret)
+ return st.st_size;
+ else
+ return EOF;
+ }
+ else
+ return _IO_SYSSEEK (fp, 0, _IO_seek_cur);
+}
+
+
+/* ftell{,o} implementation. Don't modify any state of the file pointer while
+ we try to get the current state of the stream. */
+static _IO_off64_t
+do_ftell (_IO_FILE *fp)
+{
+ _IO_off64_t result = 0;
+ bool use_cached_offset = false;
+
+ /* No point looking at unflushed data if we haven't allocated buffers
+ yet. */
+ if (fp->_IO_buf_base != NULL)
+ {
+ bool was_writing = (fp->_IO_write_ptr > fp->_IO_write_base
+ || _IO_in_put_mode (fp));
+
+ /* Adjust for unflushed data. */
+ if (!was_writing)
+ result -= fp->_IO_read_end - fp->_IO_read_ptr;
+ else
+ result += fp->_IO_write_ptr - fp->_IO_read_end;
+
+ /* It is safe to use the cached offset when available if there is
+ unbuffered data (indicating that the file handle is active) and the
+ handle is not for a file open in a+ mode. The latter condition is
+ because there could be a scenario where there is a switch from read
+ mode to write mode using an fseek to an arbitrary position. In this
+ case, there would be unbuffered data due to be appended to the end of
+ the file, but the offset may not necessarily be the end of the
+ file. It is fine to use the cached offset when the a+ stream is in
+ read mode though, since the offset is maintained correctly in that
+ case. Note that this is not a comprehensive set of cases when the
+ offset is reliable. The offset may be reliable even in some cases
+ where there is no unflushed input and the handle is active, but it's
+ just that we don't have a way to identify that condition reliably. */
+ use_cached_offset = (result != 0 && fp->_offset != _IO_pos_BAD
+ && ((fp->_flags & (_IO_IS_APPENDING | _IO_NO_READS))
+ == (_IO_IS_APPENDING | _IO_NO_READS)
+ && was_writing));
+ }
+
+ if (use_cached_offset)
+ result += fp->_offset;
+ else
+ result += get_file_offset (fp);
+
+ if (result == EOF)
+ return result;
+
+ if (result < 0)
+ {
+ __set_errno (EINVAL);
+ return EOF;
+ }
+
+ return result;
+}
+
_IO_off64_t
_IO_new_file_seekoff (fp, offset, dir, mode)
@@ -940,6 +1027,13 @@ _IO_new_file_seekoff (fp, offset, dir, mode)
_IO_off64_t result;
_IO_off64_t delta, new_offset;
long count;
+
+ /* Short-circuit into a separate function. We don't want to mix any
+ functionality and we don't want to touch anything inside the FILE
+ object. */
+ if (mode == 0)
+ return do_ftell (fp);
+
/* POSIX.1 8.2.3.7 says that after a call the fflush() the file
offset of the underlying file must be exact. */
int must_be_exact = (fp->_IO_read_base == fp->_IO_read_end
@@ -948,9 +1042,6 @@ _IO_new_file_seekoff (fp, offset, dir, mode)
bool was_writing = (fp->_IO_write_ptr > fp->_IO_write_base
|| _IO_in_put_mode (fp));
- if (mode == 0)
- dir = _IO_seek_cur, offset = 0; /* Don't move any pointers. */
-
/* Flush unwritten characters.
(This may do an unneeded write if we seek within the buffer.
But to be able to switch to reading, we would need to set
@@ -958,7 +1049,7 @@ _IO_new_file_seekoff (fp, offset, dir, mode)
which assumes file_ptr() is eGptr. Anyway, since we probably
end up flushing when we close(), it doesn't make much difference.)
FIXME: simulate mem-mapped files. */
- else if (was_writing && _IO_switch_to_get_mode (fp))
+ if (was_writing && _IO_switch_to_get_mode (fp))
return EOF;
if (fp->_IO_buf_base == NULL)
@@ -978,30 +1069,10 @@ _IO_new_file_seekoff (fp, offset, dir, mode)
{
case _IO_seek_cur:
/* Adjust for read-ahead (bytes is buffer). */
- if (mode != 0 || !was_writing)
- offset -= fp->_IO_read_end - fp->_IO_read_ptr;
- else
- {
- /* _IO_read_end coincides with fp._offset, so the actual file position
- is fp._offset - (_IO_read_end - new_write_ptr). This is fine
- even if fp._offset is not set, since fp->_IO_read_end is then at
- _IO_buf_base and this adjustment is for unbuffered output. */
- offset -= fp->_IO_read_end - fp->_IO_write_ptr;
- }
+ offset -= fp->_IO_read_end - fp->_IO_read_ptr;
if (fp->_offset == _IO_pos_BAD)
- {
- if (mode != 0)
- goto dumb;
- else
- {
- result = _IO_SYSSEEK (fp, 0, dir);
- if (result == EOF)
- return result;
-
- fp->_offset = result;
- }
- }
+ goto dumb;
/* Make offset absolute, assuming current pointer is file_ptr(). */
offset += fp->_offset;
if (offset < 0)
@@ -1028,10 +1099,6 @@ _IO_new_file_seekoff (fp, offset, dir, mode)
}
/* At this point, dir==_IO_seek_set. */
- /* If we are only interested in the current position we've found it now. */
- if (mode == 0)
- return offset;
-
/* If destination is within current buffer, optimize: */
if (fp->_offset != _IO_pos_BAD && fp->_IO_read_base != NULL
&& !_IO_in_backup (fp))
diff --git a/libio/iofdopen.c b/libio/iofdopen.c
index 066ff19..3f266f7 100644
--- a/libio/iofdopen.c
+++ b/libio/iofdopen.c
@@ -141,9 +141,6 @@ _IO_new_fdopen (fd, mode)
#ifdef _IO_MTSAFE_IO
new_f->fp.file._lock = &new_f->lock;
#endif
- /* Set up initially to use the `maybe_mmap' jump tables rather than using
- __fopen_maybe_mmap to do it, because we need them in place before we
- call _IO_file_attach or else it will allocate a buffer immediately. */
_IO_no_init (&new_f->fp.file, 0, 0, &new_f->wd,
#ifdef _G_HAVE_MMAP
(use_mmap && (read_write & _IO_NO_WRITES))
@@ -159,13 +156,12 @@ _IO_new_fdopen (fd, mode)
#if !_IO_UNIFIED_JUMPTABLES
new_f->fp.vtable = NULL;
#endif
- if (_IO_file_attach ((_IO_FILE *) &new_f->fp, fd) == NULL)
- {
- _IO_setb (&new_f->fp.file, NULL, NULL, 0);
- _IO_un_link (&new_f->fp);
- free (new_f);
- return NULL;
- }
+ /* We only need to record the fd because _IO_file_init will have unset the
+ offset. It is important to unset the cached offset because the real
+ offset in the file could change between now and when the handle is
+ activated and we would then mislead ftell into believing that we have a
+ valid offset. */
+ new_f->fp.file._fileno = fd;
new_f->fp.file._flags &= ~_IO_DELETE_DONT_CLOSE;
_IO_mask_flags (&new_f->fp.file, read_write,
diff --git a/libio/iofwide.c b/libio/iofwide.c
index 5cff632..64187e4 100644
--- a/libio/iofwide.c
+++ b/libio/iofwide.c
@@ -199,12 +199,6 @@ _IO_fwide (fp, mode)
/* From now on use the wide character callback functions. */
((struct _IO_FILE_plus *) fp)->vtable = fp->_wide_data->_wide_vtable;
-
- /* One last twist: we get the current stream position. The wide
- char streams have much more problems with not knowing the
- current position and so we should disable the optimization
- which allows the functions without knowing the position. */
- fp->_offset = _IO_SYSSEEK (fp, 0, _IO_seek_cur);
}
/* Set the mode now. */
diff --git a/libio/libioP.h b/libio/libioP.h
index 4ca723c..8a7b85b 100644
--- a/libio/libioP.h
+++ b/libio/libioP.h
@@ -397,6 +397,7 @@ extern void _IO_wdoallocbuf (_IO_FILE *) __THROW;
libc_hidden_proto (_IO_wdoallocbuf)
extern void _IO_unsave_wmarkers (_IO_FILE *) __THROW;
extern unsigned _IO_adjust_wcolumn (unsigned, const wchar_t *, int) __THROW;
+extern _IO_off64_t get_file_offset (_IO_FILE *fp);
/* Marker-related function. */
diff --git a/libio/tst-ftell-active-handler.c b/libio/tst-ftell-active-handler.c
new file mode 100644
index 0000000..175e904
--- /dev/null
+++ b/libio/tst-ftell-active-handler.c
@@ -0,0 +1,384 @@
+/* Verify that ftell returns the correct value at various points before and
+ after the handler on which it is called becomes active.
+ 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 <fcntl.h>
+#include <locale.h>
+#include <wchar.h>
+
+static int do_test (void);
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
+
+#define get_handles_fdopen(filename, fd, fp, fd_mode, mode) \
+({ \
+ int ret = 0; \
+ (fd) = open ((filename), (fd_mode), 0); \
+ if ((fd) == -1) \
+ { \
+ printf ("open failed: %m\n"); \
+ ret = 1; \
+ } \
+ else \
+ { \
+ (fp) = fdopen ((fd), (mode)); \
+ if ((fp) == NULL) \
+ { \
+ printf ("fdopen failed: %m\n"); \
+ close (fd); \
+ ret = 1; \
+ } \
+ } \
+ ret; \
+})
+
+#define get_handles_fopen(filename, fd, fp, mode) \
+({ \
+ int ret = 0; \
+ (fp) = fopen ((filename), (mode)); \
+ if ((fp) == NULL) \
+ { \
+ printf ("fopen failed: %m\n"); \
+ ret = 1; \
+ } \
+ else \
+ { \
+ (fd) = fileno (fp); \
+ if ((fd) == -1) \
+ { \
+ printf ("fileno failed: %m\n"); \
+ ret = 1; \
+ } \
+ } \
+ ret; \
+})
+
+/* 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. */
+static const void *data;
+static const char *char_data = "abcdef";
+static const wchar_t *wide_data = L"abcdef";
+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;
+
+/* Test that the value of ftell is not cached when the stream handle is not
+ active. */
+static int
+do_ftell_test (const char *filename)
+{
+ int ret = 0;
+ struct test
+ {
+ const char *mode;
+ int fd_mode;
+ size_t old_off;
+ size_t new_off;
+ } test_modes[] = {
+ /* In w, w+ and r+ modes, the file position should be at the
+ beginning of the file. After the write, the offset should be
+ updated to data_len. */
+ {"w", O_WRONLY, 0, data_len},
+ {"w+", O_RDWR, 0, data_len},
+ {"r+", O_RDWR, 0, data_len},
+ /* For 'a' and 'a+' modes, the initial file position should be the
+ current end of file. After the write, the offset has data_len
+ added to the old value. */
+ {"a", O_WRONLY, data_len, 2 * data_len},
+ {"a+", O_RDWR, 2 * data_len, 3 * data_len},
+ };
+ for (int j = 0; j < 2; j++)
+ {
+ for (int i = 0; i < sizeof (test_modes) / sizeof (struct test); i++)
+ {
+ FILE *fp;
+ int fd;
+ printf ("\tftell: %s (file, \"%s\"): ", j == 0 ? "fdopen" : "fopen",
+ test_modes[i].mode);
+
+ if (j == 0)
+ ret = get_handles_fdopen (filename, fd, fp, test_modes[i].fd_mode,
+ test_modes[i].mode);
+ else
+ ret = get_handles_fopen (filename, fd, fp, test_modes[i].mode);
+
+ if (ret != 0)
+ return ret;
+
+ long off = ftell (fp);
+ if (off != test_modes[i].old_off)
+ {
+ printf ("Incorrect old offset. Expected %zu but got %ld, ",
+ test_modes[i].old_off, off);
+ ret |= 1;
+ }
+ else
+ printf ("old offset = %ld, ", off);
+
+ /* The effect of this write on the offset should be seen in the ftell
+ call that follows it. */
+ int ret = write (fd, data, data_len);
+ off = ftell (fp);
+
+ if (off != test_modes[i].new_off)
+ {
+ printf ("Incorrect new offset. Expected %zu but got %ld\n",
+ test_modes[i].old_off, off);
+ ret |= 1;
+ }
+ else
+ printf ("new offset = %ld\n", off);
+
+ fclose (fp);
+ }
+ }
+
+ return ret;
+}
+
+/* This test opens the file for writing, moves the file offset of the
+ underlying file, writes out data and then checks if ftell trips on it. */
+static int
+do_write_test (const char *filename)
+{
+ FILE *fp = NULL;
+ int fd;
+ int ret = 0;
+ struct test
+ {
+ const char *mode;
+ int fd_mode;
+ } test_modes[] = {
+ {"w", O_WRONLY},
+ {"w+", O_RDWR},
+ {"r+", O_RDWR}
+ };
+
+ for (int j = 0; j < 2; j++)
+ {
+ for (int i = 0; i < sizeof (test_modes) / sizeof (struct test); i++)
+ {
+ printf ("\twrite: %s (file, \"%s\"): ", j == 0 ? "fopen" : "fdopen",
+ test_modes[i].mode);
+
+ if (j == 0)
+ ret = get_handles_fopen (filename, fd, fp, test_modes[i].mode);
+ else
+ ret = get_handles_fdopen (filename, fd, fp, test_modes[i].fd_mode,
+ test_modes[i].mode);
+
+ if (ret != 0)
+ return ret;
+
+ /* Move offset to just before the end of the file. */
+ off_t ret = lseek (fd, file_len - 1, SEEK_SET);
+ if (ret == -1)
+ {
+ printf ("lseek failed: %m\n");
+ ret |= 1;
+ }
+
+ /* Write some data. */
+ size_t written = fputs_func (data, fp);
+
+ if (written == EOF)
+ {
+ printf ("fputs[1] failed to write data\n");
+ ret |= 1;
+ }
+
+ /* Verify that the offset points to the end of the file. The length
+ of the file would be the original length + the length of data
+ written to it - the amount by which we moved the offset using
+ lseek. */
+ long offset = ftell (fp);
+ file_len = file_len - 1 + data_len;
+
+ if (offset != file_len)
+ {
+ printf ("Incorrect offset. Expected %zu, but got %ld\n",
+ file_len, offset);
+
+ ret |= 1;
+ }
+
+ printf ("offset = %ld\n", offset);
+ fclose (fp);
+ }
+ }
+
+ return ret;
+}
+
+/* This test opens a file in append mode, writes some data, and then verifies
+ that ftell does not trip over it. */
+static int
+do_append_test (const char *filename)
+{
+ FILE *fp = NULL;
+ int ret = 0;
+ int fd;
+
+ struct test
+ {
+ const char *mode;
+ int fd_mode;
+ } test_modes[] = {
+ {"a", O_WRONLY},
+ {"a+", O_RDWR}
+ };
+
+ for (int j = 0; j < 2; j++)
+ {
+ for (int i = 0; i < sizeof (test_modes) / sizeof (struct test); i++)
+ {
+ printf ("\tappend: %s (file, \"%s\"): ", j == 0 ? "fopen" : "fdopen",
+ test_modes[i].mode);
+
+ if (j == 0)
+ ret = get_handles_fopen (filename, fd, fp, test_modes[i].mode);
+ else
+ ret = get_handles_fdopen (filename, fd, fp, test_modes[i].fd_mode,
+ test_modes[i].mode);
+
+ if (ret != 0)
+ return ret;
+
+ /* Write some data. */
+ size_t written = fputs_func (data, fp);
+
+ if (written == EOF)
+ {
+ printf ("fputs[1] failed to write all data\n");
+ ret |= 1;
+ }
+
+ /* Verify that the offset points to the end of the file. The file
+ len is maintained by adding data_len each time to reflect the data
+ written to it. */
+ long offset = ftell (fp);
+ file_len += data_len;
+
+ if (offset != file_len)
+ {
+ printf ("Incorrect offset. Expected %zu, but got %ld\n",
+ file_len, offset);
+
+ ret |= 1;
+ }
+
+ printf ("offset = %ld\n", offset);
+ fclose (fp);
+ }
+ }
+
+ return ret;
+}
+
+static int
+do_one_test (const char *filename)
+{
+ int ret = 0;
+
+ ret |= do_ftell_test (filename);
+ ret |= do_write_test (filename);
+ ret |= do_append_test (filename);
+
+ return ret;
+}
+
+/* Run a set of tests for ftell for regular files and wide mode files. */
+static int
+do_test (void)
+{
+ int ret = 0;
+ FILE *fp = NULL;
+ char *filename;
+ size_t written;
+ int fd = create_temp_file ("tst-active-handler-tmp.", &filename);
+
+ if (fd == -1)
+ {
+ printf ("create_temp_file: %m\n");
+ return 1;
+ }
+
+ fp = fdopen (fd, "w");
+ if (fp == NULL)
+ {
+ printf ("fdopen[0]: %m\n");
+ close (fd);
+ return 1;
+ }
+
+ data = char_data;
+ data_len = strlen (char_data);
+ file_len = strlen (char_data);
+ written = fputs (data, fp);
+
+ if (written == EOF)
+ {
+ printf ("fputs[1] failed to write data\n");
+ ret = 1;
+ }
+
+ fclose (fp);
+ if (ret)
+ return ret;
+
+ /* Tests for regular files. */
+ puts ("Regular mode:");
+ fputs_func = (fputs_func_t) fputs;
+ data = char_data;
+ data_len = strlen (char_data);
+ ret |= do_one_test (filename);
+
+ /* Truncate the file before repeating the tests in wide mode. */
+ fp = fopen (filename, "w");
+ if (fp == NULL)
+ {
+ printf ("fopen failed %m\n");
+ return 1;
+ }
+ fclose (fp);
+
+ /* 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;
+ data = wide_data;
+ data_len = wcslen (wide_data);
+ ret |= do_one_test (filename);
+
+ return ret;
+}
diff --git a/libio/wfileops.c b/libio/wfileops.c
index 9cebe77..8b2e108 100644
--- a/libio/wfileops.c
+++ b/libio/wfileops.c
@@ -596,29 +596,25 @@ done:
return 0;
}
-_IO_off64_t
-_IO_wfile_seekoff (fp, offset, dir, mode)
- _IO_FILE *fp;
- _IO_off64_t offset;
- int dir;
- int mode;
+/* ftell{,o} implementation for wide mode. Don't modify any state of the file
+ pointer while we try to get the current state of the stream. */
+static _IO_off64_t
+do_ftell_wide (_IO_FILE *fp)
{
- _IO_off64_t result;
- _IO_off64_t delta, new_offset;
- long int count;
- /* POSIX.1 8.2.3.7 says that after a call the fflush() the file
- offset of the underlying file must be exact. */
- int must_be_exact = ((fp->_wide_data->_IO_read_base
- == fp->_wide_data->_IO_read_end)
- && (fp->_wide_data->_IO_write_base
- == fp->_wide_data->_IO_write_ptr));
+ _IO_off64_t result, offset = 0;
+ bool use_cached_offset = false;
- bool was_writing = ((fp->_wide_data->_IO_write_ptr
- > fp->_wide_data->_IO_write_base)
- || _IO_in_put_mode (fp));
-
- if (mode == 0)
+ /* No point looking for offsets in the buffer if it hasn't even been
+ allocated. */
+ if (fp->_wide_data->_IO_buf_base != NULL)
{
+ const wchar_t *wide_read_base;
+ const wchar_t *wide_read_ptr;
+ const wchar_t *wide_read_end;
+ bool was_writing = ((fp->_wide_data->_IO_write_ptr
+ > fp->_wide_data->_IO_write_base)
+ || _IO_in_put_mode (fp));
+
/* XXX For wide stream with backup store it is not very
reasonable to determine the offset. The pushed-back
character might require a state change and we need not be
@@ -633,14 +629,142 @@ _IO_wfile_seekoff (fp, offset, dir, mode)
return -1;
}
- /* There is no more data in the backup buffer. We can
- switch back. */
- _IO_switch_to_main_wget_area (fp);
+ /* Nothing in the backup store, so note the backed up pointers
+ without changing the state. */
+ wide_read_base = fp->_wide_data->_IO_save_base;
+ wide_read_ptr = wide_read_base;
+ wide_read_end = fp->_wide_data->_IO_save_end;
+ }
+ else
+ {
+ wide_read_base = fp->_wide_data->_IO_read_base;
+ wide_read_ptr = fp->_wide_data->_IO_read_ptr;
+ wide_read_end = fp->_wide_data->_IO_read_end;
+ }
+
+ struct _IO_codecvt *cv = fp->_codecvt;
+ int clen = (*cv->__codecvt_do_encoding) (cv);
+
+ if (!was_writing)
+ {
+ if (clen > 0)
+ {
+ offset -= (wide_read_end - wide_read_ptr) * clen;
+ offset -= fp->_IO_read_end - fp->_IO_read_ptr;
+ }
+ else
+ {
+ int nread;
+
+ size_t delta = wide_read_ptr - wide_read_base;
+ __mbstate_t state = fp->_wide_data->_IO_last_state;
+ nread = (*cv->__codecvt_do_length) (cv, &state,
+ fp->_IO_read_base,
+ fp->_IO_read_end, delta);
+ offset -= fp->_IO_read_end - fp->_IO_read_base - nread;
+ }
+ }
+ else
+ {
+ if (clen > 0)
+ offset += (fp->_wide_data->_IO_write_ptr
+ - fp->_wide_data->_IO_write_base) * clen;
+ else
+ {
+ size_t delta = (fp->_wide_data->_IO_write_ptr
+ - fp->_wide_data->_IO_write_base);
+
+ /* Allocate enough space for the conversion. */
+ size_t outsize = delta * sizeof (wchar_t);
+ char *out = malloc (outsize);
+ char *outstop = out;
+ const wchar_t *in = fp->_wide_data->_IO_write_base;
+
+ enum __codecvt_result status;
+
+ __mbstate_t state = fp->_wide_data->_IO_last_state;
+ status = (*cv->__codecvt_do_out) (cv, &state,
+ in, in + delta, &in,
+ out, out + outsize, &outstop);
+
+ /* We don't check for __codecvt_partial because it can be
+ returned on one of two conditions: either the output
+ buffer is full or the input sequence is incomplete. We
+ take care to allocate enough buffer and our input
+ sequences must be complete since they are accepted as
+ wchar_t; if not, then that is an error. */
+ if (__glibc_unlikely (status != __codecvt_ok))
+ return WEOF;
+
+ 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;
}
- dir = _IO_seek_cur, offset = 0; /* Don't move any pointers. */
+ /* It is safe to use the cached offset when available if there is
+ unbuffered data (indicating that the file handle is active) and
+ the handle is not for a file open in a+ mode. The latter
+ condition is because there could be a scenario where there is a
+ switch from read mode to write mode using an fseek to an arbitrary
+ position. In this case, there would be unbuffered data due to be
+ appended to the end of the file, but the offset may not
+ necessarily be the end of the file. It is fine to use the cached
+ offset when the a+ stream is in read mode though, since the offset
+ is maintained correctly in that case. Note that this is not a
+ comprehensive set of cases when the offset is reliable. The
+ offset may be reliable even in some cases where there is no
+ unflushed input and the handle is active, but it's just that we
+ don't have a way to identify that condition reliably. */
+ use_cached_offset = (offset != 0 && fp->_offset != _IO_pos_BAD
+ && ((fp->_flags & (_IO_IS_APPENDING | _IO_NO_READS))
+ == (_IO_IS_APPENDING | _IO_NO_READS)
+ && was_writing));
}
+ if (use_cached_offset)
+ result = fp->_offset;
+ else
+ result = get_file_offset (fp);
+
+ if (result == EOF)
+ return result;
+
+ result += offset;
+
+ return result;
+}
+
+_IO_off64_t
+_IO_wfile_seekoff (fp, offset, dir, mode)
+ _IO_FILE *fp;
+ _IO_off64_t offset;
+ int dir;
+ int mode;
+{
+ _IO_off64_t result;
+ _IO_off64_t delta, new_offset;
+ long int count;
+
+ /* Short-circuit into a separate function. We don't want to mix any
+ functionality and we don't want to touch anything inside the FILE
+ object. */
+ if (mode == 0)
+ return do_ftell_wide (fp);
+
+ /* POSIX.1 8.2.3.7 says that after a call the fflush() the file
+ offset of the underlying file must be exact. */
+ int must_be_exact = ((fp->_wide_data->_IO_read_base
+ == fp->_wide_data->_IO_read_end)
+ && (fp->_wide_data->_IO_write_base
+ == fp->_wide_data->_IO_write_ptr));
+
+ bool was_writing = ((fp->_wide_data->_IO_write_ptr
+ > fp->_wide_data->_IO_write_base)
+ || _IO_in_put_mode (fp));
+
/* Flush unwritten characters.
(This may do an unneeded write if we seek within the buffer.
But to be able to switch to reading, we would need to set
@@ -648,7 +772,7 @@ _IO_wfile_seekoff (fp, offset, dir, mode)
which assumes file_ptr() is eGptr. Anyway, since we probably
end up flushing when we close(), it doesn't make much difference.)
FIXME: simulate mem-mapped files. */
- else if (was_writing && _IO_switch_to_wget_mode (fp))
+ if (was_writing && _IO_switch_to_wget_mode (fp))
return WEOF;
if (fp->_wide_data->_IO_buf_base == NULL)
@@ -693,7 +817,6 @@ _IO_wfile_seekoff (fp, offset, dir, mode)
{
int nread;
- flushed:
delta = (fp->_wide_data->_IO_read_ptr
- fp->_wide_data->_IO_read_base);
fp->_wide_data->_IO_state = fp->_wide_data->_IO_last_state;
@@ -706,80 +829,9 @@ _IO_wfile_seekoff (fp, offset, dir, mode)
offset -= fp->_IO_read_end - fp->_IO_read_base - nread;
}
}
- else
- {
- char *new_write_ptr = fp->_IO_write_ptr;
-
- if (clen > 0)
- offset += (fp->_wide_data->_IO_write_ptr
- - fp->_wide_data->_IO_write_base) / clen;
- else
- {
- enum __codecvt_result status = __codecvt_ok;
- delta = (fp->_wide_data->_IO_write_ptr
- - fp->_wide_data->_IO_write_base);
- const wchar_t *write_base = fp->_wide_data->_IO_write_base;
-
- /* FIXME: This actually ends up in two iterations of conversion,
- one here and the next when the buffer actually gets flushed.
- It may be possible to optimize this in future so that
- wdo_write identifies already converted content and does not
- redo it. In any case, this is much better than having to
- flush buffers for every ftell. */
- do
- {
- /* There is not enough space in the buffer to do the entire
- conversion, so there is no point trying to avoid the
- buffer flush. Just do it and go back to how it was with
- the read mode. */
- if (status == __codecvt_partial
- || (delta > 0 && new_write_ptr == fp->_IO_buf_end))
- {
- if (_IO_switch_to_wget_mode (fp))
- return WEOF;
- goto flushed;
- }
-
- const wchar_t *new_wbase = fp->_wide_data->_IO_write_base;
- fp->_wide_data->_IO_state = fp->_wide_data->_IO_last_state;
- status = (*cv->__codecvt_do_out) (cv,
- &fp->_wide_data->_IO_state,
- write_base,
- write_base + delta,
- &new_wbase,
- new_write_ptr,
- fp->_IO_buf_end,
- &new_write_ptr);
-
- delta -= new_wbase - write_base;
-
- /* If there was an error, then return WEOF.
- TODO: set buffer state. */
- if (__builtin_expect (status == __codecvt_error, 0))
- return WEOF;
- }
- while (delta > 0);
- }
-
- /* _IO_read_end coincides with fp._offset, so the actual file position
- is fp._offset - (_IO_read_end - new_write_ptr). This is fine
- even if fp._offset is not set, since fp->_IO_read_end is then at
- _IO_buf_base and this adjustment is for unbuffered output. */
- offset -= fp->_IO_read_end - new_write_ptr;
- }
if (fp->_offset == _IO_pos_BAD)
- {
- if (mode != 0)
- goto dumb;
- else
- {
- result = _IO_SYSSEEK (fp, 0, dir);
- if (result == EOF)
- return result;
- fp->_offset = result;
- }
- }
+ goto dumb;
/* Make offset absolute, assuming current pointer is file_ptr(). */
offset += fp->_offset;
@@ -802,10 +854,6 @@ _IO_wfile_seekoff (fp, offset, dir, mode)
}
/* At this point, dir==_IO_seek_set. */
- /* If we are only interested in the current position we've found it now. */
- if (mode == 0)
- return offset;
-
/* If destination is within current buffer, optimize: */
if (fp->_offset != _IO_pos_BAD && fp->_IO_read_base != NULL
&& !_IO_in_backup (fp))