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/*
* SPDX-License-Identifier: GPL-2.0-or-later
*
* 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 2 of the License, or
* (at your option) any later version.
*
* Copyright (C) 2023 Red Hat, Inc. All rights reserved.
* Written by Masatake YAMATO <yamato@redhat.com>
*
* exch(1) - a command line interface for RENAME_EXCHANGE of renameat2(2).
*/
#include "c.h"
#include "nls.h"
#include <fcntl.h>
#include <getopt.h>
#ifndef HAVE_RENAMEAT2
# include <sys/syscall.h>
# include <unistd.h>
#endif
#ifndef RENAME_EXCHANGE
# define RENAME_EXCHANGE (1 << 1)
#endif
static inline int rename_exchange(const char *oldpath, const char *newpath)
{
int rc;
#if defined(HAVE_RENAMEAT2)
rc = renameat2(AT_FDCWD, oldpath, AT_FDCWD, newpath, RENAME_EXCHANGE);
#elif defined(SYS_renameat2)
rc = syscall(SYS_renameat2,
AT_FDCWD, oldpath, AT_FDCWD, newpath, RENAME_EXCHANGE);
#else
rc = -1;
errno = ENOSYS;
#endif
return rc;
}
static void __attribute__((__noreturn__)) usage(void)
{
FILE *out = stdout;
fputs(USAGE_HEADER, out);
fprintf(out, _(" %s [options] oldpath newpath\n"), program_invocation_short_name);
fputs(USAGE_SEPARATOR, out);
fputs(_("Atomically exchanges paths between two files.\n"), out);
fputs(USAGE_OPTIONS, out);
fprintf(out, USAGE_HELP_OPTIONS(30));
fprintf(out, USAGE_MAN_TAIL("exch(1)"));
exit(EXIT_SUCCESS);
}
int main(int argc, char **argv)
{
int c;
static const struct option longopts[] = {
{ "version", no_argument, NULL, 'V' },
{ "help", no_argument, NULL, 'h' },
{ NULL }
};
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
while ((c = getopt_long(argc, argv, "Vh", longopts, NULL)) != -1) {
switch (c) {
case 'V':
print_version(EXIT_SUCCESS);
case 'h':
usage();
default:
errtryhelp(EXIT_FAILURE);
}
}
if (argc - optind < 2) {
warnx(_("too few arguments"));
errtryhelp(EXIT_FAILURE);
} else if (argc - optind > 2) {
warnx(_("too many arguments"));
errtryhelp(EXIT_FAILURE);
}
if (rename_exchange(argv[optind], argv[optind + 1]) != 0) {
warn(_("failed to exchange \"%s\" and \"%s\""),
argv[optind], argv[optind + 1]);
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}
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