Ping: [PATCH] grep testsuite: test-fwrite fails with git glibc
Siddhesh Poyarekar
siddhesh@redhat.com
Tue Nov 27 17:31:00 GMT 2012
On Tue, Nov 27, 2012 at 12:05:22PM -0500, Carlos O'Donell wrote:
> Returning 0 here violates POSIX which says "shall return the number of
> elements successfully written, which may be less than nitems if a
> write error is encountered."
>
> What's your estimate on how hard is it to actually fix this correctly
> and return the number of bytes written?
>
Actually I think my comment is still wrong and we're actually doing
the right thing now. _IO_sputn will return EOF only if nothing was
written. It returns partial success if it has managed to write
something into the buffer and a subsequent overflow failed:
...
/* Next flush the (full) buffer. */
if (_IO_OVERFLOW (f, EOF) == EOF)
/* If nothing else has to be written or nothing has been written, we
must not signal the caller that the call was even partially
successful. */
return (to_do == 0 || to_do == n) ? EOF : n - to_do;
...
Here's the updated patch with the comment removed.
Regards,
Siddhesh
ChangeLog:
* libio/Makefile (tests): Add test case tst-fwrite-error.
* libio/iofwrite.c (_IO_fwrite): Return 0 on EOF.
* libio/iofwrite_u.c (fwrite_unlocked): Likewise.
* libio/tst-fwrite-error.c: New test case.
-------------- next part --------------
diff --git a/libio/Makefile b/libio/Makefile
index 9ccd6a0..83d90d0 100644
--- a/libio/Makefile
+++ b/libio/Makefile
@@ -59,7 +59,8 @@ tests = tst_swprintf tst_wprintf tst_swscanf tst_wscanf tst_getwc tst_putwc \
tst-memstream1 tst-memstream2 \
tst-wmemstream1 tst-wmemstream2 \
bug-memstream1 bug-wmemstream1 \
- tst-setvbuf1 tst-popen1 tst-fgetwc bug-wsetpos bug-fclose1 tst-fseek
+ tst-setvbuf1 tst-popen1 tst-fgetwc bug-wsetpos bug-fclose1 tst-fseek \
+ tst-fwrite-error
ifeq (yes,$(build-shared))
# Add test-fopenloc only if shared library is enabled since it depends on
# shared localedata objects.
diff --git a/libio/iofwrite.c b/libio/iofwrite.c
index d4610f7..8571352 100644
--- a/libio/iofwrite.c
+++ b/libio/iofwrite.c
@@ -43,11 +43,11 @@ _IO_fwrite (buf, size, count, fp)
written = _IO_sputn (fp, (const char *) buf, request);
_IO_release_lock (fp);
/* We have written all of the input in case the return value indicates
- this or EOF is returned. The latter is a special case where we
- simply did not manage to flush the buffer. But the data is in the
- buffer and therefore written as far as fwrite is concerned. */
- if (written == request || written == EOF)
+ this. */
+ if (written == request)
return count;
+ else if (written == EOF)
+ return 0;
else
return written / size;
}
diff --git a/libio/iofwrite_u.c b/libio/iofwrite_u.c
index a1077ee..e4a39fb 100644
--- a/libio/iofwrite_u.c
+++ b/libio/iofwrite_u.c
@@ -45,11 +45,11 @@ fwrite_unlocked (buf, size, count, fp)
{
written = _IO_sputn (fp, (const char *) buf, request);
/* We have written all of the input in case the return value indicates
- this or EOF is returned. The latter is a special case where we
- simply did not manage to flush the buffer. But the data is in the
- buffer and therefore written as far as fwrite is concerned. */
- if (written == request || written == EOF)
+ this. */
+ if (written == request)
return count;
+ else if (written == EOF)
+ return 0;
}
return written / size;
diff --git a/libio/tst-fwrite-error.c b/libio/tst-fwrite-error.c
new file mode 100644
index 0000000..3c0cf49
--- /dev/null
+++ b/libio/tst-fwrite-error.c
@@ -0,0 +1,66 @@
+/* Test of fwrite() function, adapted from gnulib-tests in grep.
+ Copyright (C) 2011-2012 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ This program 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 General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, see <http://www.gnu.org/licenses/>. */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdio.h>
+
+static int
+do_test (void)
+{
+ char tmpl[] = "/tmp/tst-fwrite-error.XXXXXX";
+ int fd = mkstemp (tmpl);
+ if (fd == -1)
+ {
+ printf ("mkstemp failed with errno %d\n", errno);
+ return 1;
+ }
+ FILE *fp = fdopen (fd, "w");
+ if (fp == NULL)
+ {
+ printf ("fdopen failed with errno %d\n", errno);
+ return 1;
+ }
+
+ char buf[5] = "world";
+ setvbuf (fp, NULL, _IONBF, 0);
+ close (fd);
+ unlink (tmpl);
+ errno = 0;
+
+ int ret = fwrite (buf, 1, sizeof (buf), fp);
+ if (ret != 0)
+ {
+ printf ("fwrite returned %d\n", ret);
+ return 1;
+ }
+ if (errno != EBADF)
+ {
+ printf ("Errno is not EBADF: %d\n", errno);
+ return 1;
+ }
+ if (ferror (fp) == 0)
+ {
+ printf ("ferror not set\n");
+ return 1;
+ }
+
+ return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
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