cachepc-qemu

Fork of AMDESE/qemu with changes for cachepc side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-qemu
Log | Files | Refs | Submodules | LICENSE | sfeed.txt

9p-util.h (2376B)

      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#ifdef O_PATH
     17#define O_PATH_9P_UTIL O_PATH
     18#else
     19#define O_PATH_9P_UTIL 0
     20#endif
     21
     22static inline void close_preserve_errno(int fd)
     23{
     24    int serrno = errno;
     25    close(fd);
     26    errno = serrno;
     27}
     28
     29static inline int openat_dir(int dirfd, const char *name)
     30{
     31    return openat(dirfd, name,
     32                  O_DIRECTORY | O_RDONLY | O_NOFOLLOW | O_PATH_9P_UTIL);
     33}
     34
     35static inline int openat_file(int dirfd, const char *name, int flags,
     36                              mode_t mode)
     37{
     38    int fd, serrno, ret;
     39
     40again:
     41    fd = openat(dirfd, name, flags | O_NOFOLLOW | O_NOCTTY | O_NONBLOCK,
     42                mode);
     43    if (fd == -1) {
     44        if (errno == EPERM && (flags & O_NOATIME)) {
     45            /*
     46             * The client passed O_NOATIME but we lack permissions to honor it.
     47             * Rather than failing the open, fall back without O_NOATIME. This
     48             * doesn't break the semantics on the client side, as the Linux
     49             * open(2) man page notes that O_NOATIME "may not be effective on
     50             * all filesystems". In particular, NFS and other network
     51             * filesystems ignore it entirely.
     52             */
     53            flags &= ~O_NOATIME;
     54            goto again;
     55        }
     56        return -1;
     57    }
     58
     59    serrno = errno;
     60    /* O_NONBLOCK was only needed to open the file. Let's drop it. We don't
     61     * do that with O_PATH since fcntl(F_SETFL) isn't supported, and openat()
     62     * ignored it anyway.
     63     */
     64    if (!(flags & O_PATH_9P_UTIL)) {
     65        ret = fcntl(fd, F_SETFL, flags);
     66        assert(!ret);
     67    }
     68    errno = serrno;
     69    return fd;
     70}
     71
     72ssize_t fgetxattrat_nofollow(int dirfd, const char *path, const char *name,
     73                             void *value, size_t size);
     74int fsetxattrat_nofollow(int dirfd, const char *path, const char *name,
     75                         void *value, size_t size, int flags);
     76ssize_t flistxattrat_nofollow(int dirfd, const char *filename,
     77                              char *list, size_t size);
     78ssize_t fremovexattrat_nofollow(int dirfd, const char *filename,
     79                                const char *name);
     80
     81#endif