Files
systemd/src/basic/stdio-util.h
Zbigniew Jędrzejewski-Szmek 048a94c8f6 basic/stdio-util: use a fixed message in xsprintf
We put the name of the variable in the message, but it is a local variable
and the name does not have global meaning. We end up with pointless copies
of the error string:

$ strings build/libsystemd.so.0.40.0 | grep 'big enough'
xsprintf: p[] must be big enough
xsprintf: error[] must be big enough
xsprintf: prefix[] must be big enough
xsprintf: pty[] must be big enough
xsprintf: mode[] must be big enough
xsprintf: t[] must be big enough
xsprintf: s[] must be big enough
xsprintf: spid[] must be big enough
xsprintf: header_priority[] must be big enough
xsprintf: header_pid[] must be big enough
xsprintf: path[] must be big enough
xsprintf: buf[] must be big enough

The error message already shows the file, line, and function name, which
is enough to identify the problem:

  Assertion 'xsprintf: buffer too small' failed at src/test/test-string-util.c:20, function test_xsprintf(). Aborting.
2025-07-08 13:02:37 +02:00

71 lines
3.9 KiB
C

/* SPDX-License-Identifier: LGPL-2.1-or-later */
#pragma once
#include <printf.h>
#include <stdio.h>
#include "forward.h"
_printf_(3, 4)
static inline char* snprintf_ok(char *buf, size_t len, const char *format, ...) {
va_list ap;
int r;
va_start(ap, format);
r = vsnprintf(buf, len, format, ap);
va_end(ap);
return r >= 0 && (size_t) r < len ? buf : NULL;
}
#define xsprintf(buf, fmt, ...) \
assert_message_se(snprintf_ok(buf, ELEMENTSOF(buf), fmt, ##__VA_ARGS__), "xsprintf: buffer too small")
#define VA_FORMAT_ADVANCE(format, ap) \
do { \
int _argtypes[128]; \
size_t _i, _k; \
/* See https://github.com/google/sanitizers/issues/992 */ \
if (HAS_FEATURE_MEMORY_SANITIZER) \
memset(_argtypes, 0, sizeof(_argtypes)); \
_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(); \
} \
} \
} while (false)