LXR qemu/hw/9pfs/9p-util-darwin.c

   1/*
   2 * 9p utilities (Darwin Implementation)
   3 *
   4 * This work is licensed under the terms of the GNU GPL, version 2 or later.
   5 * See the COPYING file in the top-level directory.
   6 */
   7
   8#include "qemu/osdep.h"
   9#include "qemu/xattr.h"
  10#include "qapi/error.h"
  11#include "qemu/error-report.h"
  12#include "9p-util.h"
  13
  14ssize_t fgetxattrat_nofollow(int dirfd, const char *filename, const char *name,
  15                             void *value, size_t size)
  16{
  17    int ret;
  18    int fd = openat_file(dirfd, filename,
  19                         O_RDONLY | O_PATH_9P_UTIL | O_NOFOLLOW, 0);
  20    if (fd == -1) {
  21        return -1;
  22    }
  23    ret = fgetxattr(fd, name, value, size, 0, 0);
  24    close_preserve_errno(fd);
  25    return ret;
  26}
  27
  28ssize_t flistxattrat_nofollow(int dirfd, const char *filename,
  29                              char *list, size_t size)
  30{
  31    int ret;
  32    int fd = openat_file(dirfd, filename,
  33                         O_RDONLY | O_PATH_9P_UTIL | O_NOFOLLOW, 0);
  34    if (fd == -1) {
  35        return -1;
  36    }
  37    ret = flistxattr(fd, list, size, 0);
  38    close_preserve_errno(fd);
  39    return ret;
  40}
  41
  42ssize_t fremovexattrat_nofollow(int dirfd, const char *filename,
  43                                const char *name)
  44{
  45    int ret;
  46    int fd = openat_file(dirfd, filename, O_PATH_9P_UTIL | O_NOFOLLOW, 0);
  47    if (fd == -1) {
  48        return -1;
  49    }
  50    ret = fremovexattr(fd, name, 0);
  51    close_preserve_errno(fd);
  52    return ret;
  53}
  54
  55int fsetxattrat_nofollow(int dirfd, const char *filename, const char *name,
  56                         void *value, size_t size, int flags)
  57{
  58    int ret;
  59    int fd = openat_file(dirfd, filename, O_PATH_9P_UTIL | O_NOFOLLOW, 0);
  60    if (fd == -1) {
  61        return -1;
  62    }
  63    ret = fsetxattr(fd, name, value, size, 0, flags);
  64    close_preserve_errno(fd);
  65    return ret;
  66}
  67
  68/*
  69 * As long as mknodat is not available on macOS, this workaround
  70 * using pthread_fchdir_np is needed.
  71 *
  72 * Radar filed with Apple for implementing mknodat:
  73 * rdar://FB9862426 (https://openradar.appspot.com/FB9862426)
  74 */
  75#if defined CONFIG_PTHREAD_FCHDIR_NP
  76
  77static int create_socket_file_at_cwd(const char *filename, mode_t mode) {
  78    int fd, err;
  79    struct sockaddr_un addr = {
  80        .sun_family = AF_UNIX
  81    };
  82
  83    err = snprintf(addr.sun_path, sizeof(addr.sun_path), "./%s", filename);
  84    if (err < 0 || err >= sizeof(addr.sun_path)) {
  85        errno = ENAMETOOLONG;
  86        return -1;
  87    }
  88    fd = socket(PF_UNIX, SOCK_DGRAM, 0);
  89    if (fd == -1) {
  90        return fd;
  91    }
  92    err = bind(fd, (struct sockaddr *) &addr, sizeof(addr));
  93    if (err == -1) {
  94        goto out;
  95    }
  96    /*
  97     * FIXME: Should rather be using descriptor-based fchmod() on the
  98     * socket file descriptor above (preferably before bind() call),
  99     * instead of path-based fchmodat(), to prevent concurrent transient
 100     * state issues between creating the named FIFO file at bind() and
 101     * delayed adjustment of permissions at fchmodat(). However currently
 102     * macOS (12.x) does not support such operations on socket file
 103     * descriptors yet.
 104     *
 105     * Filed report with Apple: FB9997731
 106     */
 107    err = fchmodat(AT_FDCWD, filename, mode, AT_SYMLINK_NOFOLLOW);
 108out:
 109    close_preserve_errno(fd);
 110    return err;
 111}
 112
 113int qemu_mknodat(int dirfd, const char *filename, mode_t mode, dev_t dev)
 114{
 115    int preserved_errno, err;
 116
 117    if (S_ISREG(mode) || !(mode & S_IFMT)) {
 118        int fd = openat_file(dirfd, filename, O_CREAT, mode);
 119        if (fd == -1) {
 120            return fd;
 121        }
 122        close(fd);
 123        return 0;
 124    }
 125    if (!pthread_fchdir_np) {
 126        error_report_once("pthread_fchdir_np() not available on this version of macOS");
 127        errno = ENOTSUP;
 128        return -1;
 129    }
 130    if (pthread_fchdir_np(dirfd) < 0) {
 131        return -1;
 132    }
 133    if (S_ISSOCK(mode)) {
 134        err = create_socket_file_at_cwd(filename, mode);
 135    } else {
 136        err = mknod(filename, mode, dev);
 137    }
 138    preserved_errno = errno;
 139    /* Stop using the thread-local cwd */
 140    pthread_fchdir_np(-1);
 141    if (err < 0) {
 142        errno = preserved_errno;
 143    }
 144    return err;
 145}
 146
 147#endif
 148