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71 lines
1.5 KiB
C
71 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-3.0-or-later */
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/*
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* Copyright (C) 2018 - David Oberhollenzer
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <errno.h>
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#include "util.h"
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FILE *fopenat(int dirfd, const char *filename, const char *mode)
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{
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const char *ptr = mode;
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int fd, flags = 0;
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FILE *fp;
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switch (*(ptr++)) {
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case 'r':
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flags = O_RDONLY;
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break;
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case 'w':
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flags = O_WRONLY | O_CREAT | O_TRUNC;
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break;
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case 'a':
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flags = O_WRONLY | O_CREAT | O_APPEND;
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break;
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default:
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errno = EINVAL;
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return NULL;
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}
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if (*ptr == '+') {
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flags = (flags & ~(O_RDONLY | O_WRONLY)) | O_RDWR;
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++ptr;
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}
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if (*ptr == 'b')
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++ptr;
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if (*ptr != '\0') {
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errno = EINVAL;
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return NULL;
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}
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fd = openat(dirfd, filename, flags, 0644);
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if (fd == -1)
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return NULL;
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fp = fdopen(fd, mode);
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if (fp == NULL)
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close(fd);
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return fp;
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}
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