xref: /openbmc/qemu/hw/9pfs/9p-util.h (revision 39164c13)
1 /*
2  * 9p utilities
3  *
4  * Copyright IBM, Corp. 2017
5  *
6  * Authors:
7  *  Greg Kurz <groug@kaod.org>
8  *
9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
10  * See the COPYING file in the top-level directory.
11  */
12 
13 #ifndef QEMU_9P_UTIL_H
14 #define QEMU_9P_UTIL_H
15 
16 static inline void close_preserve_errno(int fd)
17 {
18     int serrno = errno;
19     close(fd);
20     errno = serrno;
21 }
22 
23 static inline int openat_dir(int dirfd, const char *name)
24 {
25     return openat(dirfd, name, O_DIRECTORY | O_RDONLY | O_PATH);
26 }
27 
28 static inline int openat_file(int dirfd, const char *name, int flags,
29                               mode_t mode)
30 {
31     int fd, serrno, ret;
32 
33     fd = openat(dirfd, name, flags | O_NOFOLLOW | O_NOCTTY | O_NONBLOCK,
34                 mode);
35     if (fd == -1) {
36         return -1;
37     }
38 
39     serrno = errno;
40     /* O_NONBLOCK was only needed to open the file. Let's drop it. */
41     ret = fcntl(fd, F_SETFL, flags);
42     assert(!ret);
43     errno = serrno;
44     return fd;
45 }
46 
47 int relative_openat_nofollow(int dirfd, const char *path, int flags,
48                              mode_t mode);
49 ssize_t fgetxattrat_nofollow(int dirfd, const char *path, const char *name,
50                              void *value, size_t size);
51 int fsetxattrat_nofollow(int dirfd, const char *path, const char *name,
52                          void *value, size_t size, int flags);
53 
54 #endif
55