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/*
* Copyright (c) 2018 Eugene Syromyatnikov <evgsyr@gmail.com>
* All rights reserved.
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*/
#ifndef STRACE_XSTRING_H
# define STRACE_XSTRING_H
# include <stdarg.h>
# include <stdio.h>
# include "error_prints.h"
# include "gcc_compat.h"
/**
* Print to static buffer and die on (really unexpected) errors and overflows.
* Shouldn't be used directly; please refer to helper macros xsnprintf and
* xsprint instead.
*
* @param str String buffer to print into.
* @param size Size of the string buffer in bytes.
* @param func Function name from which this function is called.
* @param argstr Stringified arguments (including format argument).
* @param format Format string.
* @param ... Format arguments.
* @return Number of characters printed, excluding terminating null byte
* (the same as s(n)printf).
*/
static inline int ATTRIBUTE_FORMAT((printf, 5, 6))
xsnprintf_(char *str, size_t size, const char *func, const char *argstr,
const char *format, ...)
{
int ret;
va_list ap;
va_start(ap, format);
ret = vsnprintf(str, size, format, ap);
va_end(ap);
if (ret < 0 || (unsigned int) ret >= size)
error_msg_and_die("%s: got unexpected return value %d for "
"snprintf(buf, %zu, %s)",
func, ret, size, argstr);
return ret;
}
/**
* snprintf that dies on (really unexpected) errors and overflows.
*
* @param str_ String buffer to print into.
* @param size_ Size of the string buffer in bytes.
* @param fmt_ Format string.
* @param ... Format arguments.
*/
# define xsnprintf(str_, size_, fmt_, ...) \
xsnprintf_((str_), (size_), __func__, #fmt_ ", " #__VA_ARGS__, \
(fmt_), __VA_ARGS__)
/**
* Print to a character array buffer and die on (really unexpected) errors and
* overflows. Buffer size is obtained with sizeof().
*
* @param str_ Character array buffer to print into.
* @param fmt_ Format string.
* @param ... Format arguments.
*/
# define xsprintf(str_, fmt_, ...) \
xsnprintf((str_), sizeof(str_) + MUST_BE_ARRAY(str_), (fmt_), \
__VA_ARGS__)
static inline size_t
get_pos_diff_(char *str, size_t size, char *pos, const char *func,
const char *call)
{
if ((str + size) < str)
error_msg_and_die("%s: string size overflow (%p+%zu) in %s",
func, str, size, call);
if (pos > (str + size))
error_msg_and_die("%s: got position (%p) beyond string "
"(%p+%zu) in %s",
func, pos, str, size, call);
if (pos < str)
error_msg_and_die("%s: got position %p before string %p in %s",
func, pos, str, call);
return pos - str;
}
/**
* Helper function for constructing string in a character array by appending
* new formatted parts. Returns new position. Fails on error or buffer
* overflow, in line with the rest of x* functions. Obtains buffer size via
* sizeof(str_).
*
* @param str_ Character array buffer to print into.
* @param pos_ Current position.
* @param fmt_ Format string.
* @param ... Format arguments.
* @return New position.
*/
# define xappendstr(str_, pos_, fmt_, ...) \
(xsnprintf((pos_), sizeof(str_) + MUST_BE_ARRAY(str_) - \
get_pos_diff_((str_), sizeof(str_), (pos_), __func__, \
"xappendstr(" #str_ ", " #pos_ ", " #fmt_ ", " \
#__VA_ARGS__ ")"), \
(fmt_), ##__VA_ARGS__) + (pos_))
#endif /* !STRACE_XSTRING_H */
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