strace/error_prints.c

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/*
* Copyright (c) 1999-2018 The strace developers.
* All rights reserved.
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <errno.h>
#include <stdarg.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include "error_prints.h"
#ifndef HAVE_PROGRAM_INVOCATION_NAME
extern char *program_invocation_name;
#endif
static void
verror_msg(int err_no, const char *fmt, va_list p)
{
char *msg;
fflush(NULL);
/* We want to print entire message with single fprintf to ensure
* message integrity if stderr is shared with other programs.
* Thus we use vasprintf + single fprintf.
*/
msg = NULL;
if (vasprintf(&msg, fmt, p) >= 0) {
if (err_no)
fprintf(stderr, "%s: %s: %s\n",
program_invocation_name, msg, strerror(err_no));
else
fprintf(stderr, "%s: %s\n",
program_invocation_name, msg);
free(msg);
} else {
/* malloc in vasprintf failed, try it without malloc */
fprintf(stderr, "%s: ", program_invocation_name);
vfprintf(stderr, fmt, p);
if (err_no)
fprintf(stderr, ": %s\n", strerror(err_no));
else
putc('\n', stderr);
}
/* We don't switch stderr to buffered, thus fprintf(stderr)
* always flushes its output and this is not necessary: */
/* fflush(stderr); */
}
void
error_msg(const char *fmt, ...)
{
va_list p;
va_start(p, fmt);
verror_msg(0, fmt, p);
va_end(p);
}
void
error_msg_and_die(const char *fmt, ...)
{
va_list p;
va_start(p, fmt);
verror_msg(0, fmt, p);
va_end(p);
die();
}
void
error_msg_and_help(const char *fmt, ...)
{
if (fmt != NULL) {
va_list p;
va_start(p, fmt);
verror_msg(0, fmt, p);
va_end(p);
}
fprintf(stderr, "Try '%s -h' for more information.\n",
program_invocation_name);
die();
}
void
perror_msg(const char *fmt, ...)
{
va_list p;
va_start(p, fmt);
verror_msg(errno, fmt, p);
va_end(p);
}
void
perror_msg_and_die(const char *fmt, ...)
{
va_list p;
va_start(p, fmt);
verror_msg(errno, fmt, p);
va_end(p);
die();
}