hw/9pfs/9p-util.h

   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 #ifdef O_PATH
  26 #define OPENAT_DIR_O_PATH O_PATH
  27 #else
  28 #define OPENAT_DIR_O_PATH 0
  29 #endif
  30     return openat(dirfd, name,
  31                   O_DIRECTORY | O_RDONLY | O_NOFOLLOW | OPENAT_DIR_O_PATH);
  32 }
  33
  34 static inline int openat_file(int dirfd, const char *name, int flags,
  35                               mode_t mode)
  36 {
  37     int fd, serrno, ret;
  38
  39     fd = openat(dirfd, name, flags | O_NOFOLLOW | O_NOCTTY | O_NONBLOCK,
  40                 mode);
  41     if (fd == -1) {
  42         return -1;
  43     }
  44
  45     serrno = errno;
  46     /* O_NONBLOCK was only needed to open the file. Let's drop it. */
  47     ret = fcntl(fd, F_SETFL, flags);
  48     assert(!ret);
  49     errno = serrno;
  50     return fd;
  51 }
  52
  53 int relative_openat_nofollow(int dirfd, const char *path, int flags,
  54                              mode_t mode);
  55 ssize_t fgetxattrat_nofollow(int dirfd, const char *path, const char *name,
  56                              void *value, size_t size);
  57 int fsetxattrat_nofollow(int dirfd, const char *path, const char *name,
  58                          void *value, size_t size, int flags);
  59
  60 #endif