Eric Blake <[EMAIL PROTECTED]> wrote:
> According to Andreas Schwab on 10/19/2007 6:58 AM:
>> Jim Meyering <[EMAIL PROTECTED]> writes:
>>
>>> Could it be a bug in printf for failing, yet not setting the
>>> stream-failure indicator that is checked by close_stdout's ferror?
>>
>> A failure from printf does not necessarily mean an output failure. It
>> can also be ENOMEM or EILSEQ, which are unrelated to output.
>
> Wow. You're right. Which means the return value of printf/fprintf must
> always be checked in a secure program.
'Fraid so. At least for now.
Hard to believe that POSIX intended to impose such a requirement.
Here's the proposed gnulib module:
Hmm.. need to add a copyright on the .h file.
And documentation.
Then, s/printf/xprintf/ in coreutils' printf.c and the problem is solved.
----------------
New module: xprintf
* modules/xprintf, lib/xprintf.c, lib/xprintf.h: New files.
---
ChangeLog | 5 ++++
lib/xprintf.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
lib/xprintf.h | 24 +++++++++++++++++++++++
modules/xprintf | 25 ++++++++++++++++++++++++
4 files changed, 110 insertions(+), 0 deletions(-)
create mode 100644 lib/xprintf.c
create mode 100644 lib/xprintf.h
create mode 100644 modules/xprintf
diff --git a/ChangeLog b/ChangeLog
index b39e171..dbf680e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2007-10-19 Jim Meyering <[EMAIL PROTECTED]>
+
+ New module: xprintf
+ * modules/xprintf, lib/xprintf.c, lib/xprintf.h: New files.
+
2007-10-18 Bruno Haible <[EMAIL PROTECTED]>
* lib/vasnprintf.c (VASNPRINTF): Don't use %n on glibc >= 2.3 systems.
diff --git a/lib/xprintf.c b/lib/xprintf.c
new file mode 100644
index 0000000..a794418
--- /dev/null
+++ b/lib/xprintf.c
@@ -0,0 +1,56 @@
+/* printf wrappers that fail immediately for non-file-related errors
+ Copyright (C) 2007 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 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
+ 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/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "xprintf.h"
+
+#include <errno.h>
+#include <stdarg.h>
+
+#include "error.h"
+#include "exitfail.h"
+#include "gettext.h"
+
+/* Just like printf, but call error if it fails for any reason
+ for which printf does not set the stream error indicator. */
+int
+xprintf (char const *restrict format, ...)
+{
+ va_list args;
+ va_start (args, format);
+ int err = vprintf (format, args);
+ if (err && (errno == EILSEQ || errno == EINVAL || errno == ENOMEM))
+ error (exit_failure, errno, gettext ("write error"));
+
+ return err;
+}
+
+/* Just like fprintf, but call error if it fails for any reason
+ for which printf does not set the stream error indicator. */
+int
+xfprintf (FILE *restrict stream, char const *restrict format, ...)
+{
+ va_list args;
+ va_start (args, format);
+ int err = vfprintf (stream, format, args);
+ if (err && (errno == EILSEQ || errno == EINVAL || errno == ENOMEM))
+ error (exit_failure, errno, gettext ("write error"));
+
+ return err;
+}
diff --git a/lib/xprintf.h b/lib/xprintf.h
new file mode 100644
index 0000000..be20b7a
--- /dev/null
+++ b/lib/xprintf.h
@@ -0,0 +1,24 @@
+#ifndef _XPRINTF_H
+#define _XPRINTF_H
+
+#include <stdio.h>
+
+#ifndef __attribute__
+/* This feature is available in gcc versions 2.5 and later. */
+# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 5) || __STRICT_ANSI__
+# define __attribute__(Spec) /* empty */
+# endif
+/* The __-protected variants of `format' and `printf' attributes
+ are accepted by gcc versions 2.6.4 (effectively 2.7) and later. */
+# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 7)
+# define __format__ format
+# define __printf__ printf
+# endif
+#endif
+
+extern int xprintf (char const *restrict format, ...)
+ __attribute__ ((__format__ (__printf__, 1, 2)));
+extern int xfprintf (FILE *restrict stream, char const *restrict format, ...)
+ __attribute__ ((__format__ (__printf__, 2, 3)));
+
+#endif
diff --git a/modules/xprintf b/modules/xprintf
new file mode 100644
index 0000000..1425971
--- /dev/null
+++ b/modules/xprintf
@@ -0,0 +1,25 @@
+Description:
+a wrapper around printf that calls error upon ENOMEM or EILSEQ errors
+
+Files:
+lib/xprintf.h
+lib/xprintf.c
+
+Depends-on:
+error
+exitfail
+stdio
+
+configure.ac:
+
+Makefile.am:
+lib_SOURCES += xprintf.h xprintf.c
+
+Include:
+"xprintf.h"
+
+License:
+LGPL
+
+Maintainer:
+Jim Meyering
--
1.5.3.4.206.g58ba4
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