Systemd/src/basic/stdio-util.h
Zbigniew Jędrzejewski-Szmek 73fc96c8ac udev/net-id: check all snprintf return values
gcc-8 throws an error if it knows snprintf might truncate output and the
return value is ignored:
../src/udev/udev-builtin-net_id.c: In function 'dev_pci_slot':
../src/udev/udev-builtin-net_id.c:297:47: error: '%s' directive output may be truncated writing up to 255 bytes into a region of size between 0 and 4095 [-Werror=format-truncation=]
                 snprintf(str, sizeof str, "%s/%s/address", slots, dent->d_name);
                                               ^~
../src/udev/udev-builtin-net_id.c:297:17: note: 'snprintf' output between 10 and 4360 bytes into a destination of size 4096
                 snprintf(str, sizeof str, "%s/%s/address", slots, dent->d_name);
                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors

Let's check all return values. This actually makes the code better, because there's
no point in trying to open a file when the name has been truncated, etc.
2018-02-23 11:15:42 +01:00

80 lines
4.3 KiB
C

/* SPDX-License-Identifier: LGPL-2.1+ */
#pragma once
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd 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.
systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <printf.h>
#include <stdarg.h>
#include <stdio.h>
#include <sys/types.h>
#include "macro.h"
#define snprintf_ok(buf, len, fmt, ...) \
((size_t) snprintf(buf, len, fmt, __VA_ARGS__) < (len))
#define xsprintf(buf, fmt, ...) \
assert_message_se(snprintf_ok(buf, ELEMENTSOF(buf), fmt, __VA_ARGS__), "xsprintf: " #buf "[] must be big enough")
#define VA_FORMAT_ADVANCE(format, ap) \
do { \
int _argtypes[128]; \
size_t _i, _k; \
_k = parse_printf_format((format), ELEMENTSOF(_argtypes), _argtypes); \
assert(_k < ELEMENTSOF(_argtypes)); \
for (_i = 0; _i < _k; _i++) { \
if (_argtypes[_i] & PA_FLAG_PTR) { \
(void) va_arg(ap, void*); \
continue; \
} \
\
switch (_argtypes[_i]) { \
case PA_INT: \
case PA_INT|PA_FLAG_SHORT: \
case PA_CHAR: \
(void) va_arg(ap, int); \
break; \
case PA_INT|PA_FLAG_LONG: \
(void) va_arg(ap, long int); \
break; \
case PA_INT|PA_FLAG_LONG_LONG: \
(void) va_arg(ap, long long int); \
break; \
case PA_WCHAR: \
(void) va_arg(ap, wchar_t); \
break; \
case PA_WSTRING: \
case PA_STRING: \
case PA_POINTER: \
(void) va_arg(ap, void*); \
break; \
case PA_FLOAT: \
case PA_DOUBLE: \
(void) va_arg(ap, double); \
break; \
case PA_DOUBLE|PA_FLAG_LONG_DOUBLE: \
(void) va_arg(ap, long double); \
break; \
default: \
assert_not_reached("Unknown format string argument."); \
} \
} \
} while (false)