/* Detect write error on a stream.
- Copyright (C) 2003-2006 Free Software Foundation, Inc.
+ Copyright (C) 2003-2006, 2008, 2009 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>, 2003.
- This program is free software; you can redistribute it and/or modify
+ 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 2, or (at your option)
- any later version.
+ the Free Software Foundation; either version 3 of the License, 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
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, write to the Free Software Foundation,
- Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <config.h>
#include <errno.h>
#include <stdbool.h>
-int
-fwriteerror (FILE *fp)
+static int
+do_fwriteerror (FILE *fp, bool ignore_ebadf)
{
/* State to allow multiple calls to fwriteerror (stdout). */
static bool stdout_closed = false;
- if (fp == stdout && stdout_closed)
- return 0;
+ if (fp == stdout)
+ {
+ if (stdout_closed)
+ return 0;
+
+ /* If we are closing stdout, don't attempt to do it later again. */
+ stdout_closed = true;
+ }
- /* Need to
+ /* This function returns an error indication if there was a previous failure
+ or if fclose failed, with two exceptions:
+ - Ignore an fclose failure if there was no previous error, no data
+ remains to be flushed, and fclose failed with EBADF. That can
+ happen when a program like cp is invoked like this `cp a b >&-'
+ (i.e., with standard output closed) and doesn't generate any
+ output (hence no previous error and nothing to be flushed).
+ - Ignore an fclose failure due to EPIPE. That can happen when a
+ program blocks or ignores SIGPIPE, and the output pipe or socket
+ has no readers now. The EPIPE tells us that we should stop writing
+ to this output. That's what we are doing anyway here.
+
+ Need to
1. test the error indicator of the stream,
2. flush the buffers both in userland and in the kernel, through fclose,
testing for error again. */
goto close_preserving_errno; /* errno is set here */
/* Give up on errno. */
errno = 0;
- close_preserving_errno:
- /* There's an error. Nevertheless call fclose(fp), for consistency
- with the other cases. */
- {
- int saved_errno = errno;
- fclose (fp);
- errno = saved_errno;
- return -1;
- }
+ goto close_preserving_errno;
}
- /* If we are closing stdout, don't attempt to do it later again. */
- if (fp == stdout)
- stdout_closed = true;
-
- if (fclose (fp))
- return -1; /* errno is set here */
+ if (ignore_ebadf)
+ {
+ /* We need an explicit fflush to tell whether some output was already
+ done on FP. */
+ if (fflush (fp))
+ goto close_preserving_errno; /* errno is set here */
+ if (fclose (fp) && errno != EBADF)
+ goto got_errno; /* errno is set here */
+ }
+ else
+ {
+ if (fclose (fp))
+ goto got_errno; /* errno is set here */
+ }
return 0;
+
+ close_preserving_errno:
+ /* There's an error. Nevertheless call fclose(fp), for consistency
+ with the other cases. */
+ {
+ int saved_errno = errno;
+ fclose (fp);
+ errno = saved_errno;
+ }
+ got_errno:
+ /* There's an error. Ignore EPIPE. */
+ if (errno == EPIPE)
+ return 0;
+ else
+ return -1;
+}
+
+int
+fwriteerror (FILE *fp)
+{
+ return do_fwriteerror (fp, false);
+}
+
+int
+fwriteerror_no_ebadf (FILE *fp)
+{
+ return do_fwriteerror (fp, true);
}
#if TEST
/* Name of a file on which writing fails. On systems without /dev/full,
- you can choose a filename on a full filesystem. */
+ you can choose a filename on a full file system. */
#define UNWRITABLE_FILE "/dev/full"
int