diff options
| -rw-r--r-- | lib/Makemodule.am | 3 | ||||
| -rw-r--r-- | lib/include/util.h | 7 | ||||
| -rw-r--r-- | lib/util/fopenat.c | 70 |
3 files changed, 79 insertions, 1 deletions
diff --git a/lib/Makemodule.am b/lib/Makemodule.am index 66652bc..9f22547 100644 --- a/lib/Makemodule.am +++ b/lib/Makemodule.am @@ -8,7 +8,8 @@ libinit_a_CFLAGS = $(AM_CFLAGS) libutil_a_SOURCES = lib/util/argv_exec.c lib/util/enum_by_name.c libutil_a_SOURCES += lib/util/enum_to_name.c lib/util/mksock.c -libutil_a_SOURCES += lib/util/print_version.c $(HEADRS) +libutil_a_SOURCES += lib/util/print_version.c lib/util/fopenat.c +libutil_a_SOURCES += lib/include/util.h libutil_a_CPPFLAGS = $(AM_CPPFLAGS) libutil_a_CFLAGS = $(AM_CFLAGS) diff --git a/lib/include/util.h b/lib/include/util.h index 925a1f0..f300329 100644 --- a/lib/include/util.h +++ b/lib/include/util.h @@ -21,6 +21,7 @@ #include <sys/types.h> #include <stdbool.h> #include <stddef.h> +#include <stdio.h> #include "config.h" @@ -83,5 +84,11 @@ int setup_tty(const char *tty, bool truncate); NORETURN void argv_exec(exec_t *e); +/* + Similar to openat: opens a file relative to a dirfd, but returns + a FILE pointer instead of an fd. + */ +FILE *fopenat(int fd, const char *filename, const char *mode); + #endif /* UTIL_H */ diff --git a/lib/util/fopenat.c b/lib/util/fopenat.c new file mode 100644 index 0000000..6bb9dd8 --- /dev/null +++ b/lib/util/fopenat.c @@ -0,0 +1,70 @@ +/* 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; +} |