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/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
* Copyright (C) 2018 - David Oberhollenzer
*
* 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 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <errno.h>
#include "util.h"
FILE *fopenat(int dirfd, const char *filename, const char *mode)
{
const char *ptr = mode;
int fd, flags = 0;
FILE *fp;
switch (*(ptr++)) {
case 'r':
flags = O_RDONLY;
break;
case 'w':
flags = O_WRONLY | O_CREAT | O_TRUNC;
break;
case 'a':
flags = O_WRONLY | O_CREAT | O_APPEND;
break;
default:
errno = EINVAL;
return NULL;
}
if (*ptr == '+') {
flags = (flags & ~(O_RDONLY | O_WRONLY)) | O_RDWR;
++ptr;
}
if (*ptr == 'b')
++ptr;
if (*ptr != '\0') {
errno = EINVAL;
return NULL;
}
fd = openat(dirfd, filename, flags, 0644);
if (fd == -1)
return NULL;
fp = fdopen(fd, mode);
if (fp == NULL)
close(fd);
return fp;
}
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