1 files changed, 147 insertions, 0 deletions
diff --git a/hw/9pfs/9p-util-darwin.c b/hw/9pfs/9p-util-darwin.c
new file mode 100644
index 00000000..95146e73
--- /dev/null
+++ b/hw/9pfs/9p-util-darwin.c
@@ -0,0 +1,147 @@
+/*
+ * 9p utilities (Darwin Implementation)
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/xattr.h"
+#include "qapi/error.h"
+#include "qemu/error-report.h"
+#include "9p-util.h"
+
+ssize_t fgetxattrat_nofollow(int dirfd, const char *filename, const char *name,
+                             void *value, size_t size)
+{
+    int ret;
+    int fd = openat_file(dirfd, filename,
+                         O_RDONLY | O_PATH_9P_UTIL | O_NOFOLLOW, 0);
+    if (fd == -1) {
+        return -1;
+    }
+    ret = fgetxattr(fd, name, value, size, 0, 0);
+    close_preserve_errno(fd);
+    return ret;
+}
+
+ssize_t flistxattrat_nofollow(int dirfd, const char *filename,
+                              char *list, size_t size)
+{
+    int ret;
+    int fd = openat_file(dirfd, filename,
+                         O_RDONLY | O_PATH_9P_UTIL | O_NOFOLLOW, 0);
+    if (fd == -1) {
+        return -1;
+    }
+    ret = flistxattr(fd, list, size, 0);
+    close_preserve_errno(fd);
+    return ret;
+}
+
+ssize_t fremovexattrat_nofollow(int dirfd, const char *filename,
+                                const char *name)
+{
+    int ret;
+    int fd = openat_file(dirfd, filename, O_PATH_9P_UTIL | O_NOFOLLOW, 0);
+    if (fd == -1) {
+        return -1;
+    }
+    ret = fremovexattr(fd, name, 0);
+    close_preserve_errno(fd);
+    return ret;
+}
+
+int fsetxattrat_nofollow(int dirfd, const char *filename, const char *name,
+                         void *value, size_t size, int flags)
+{
+    int ret;
+    int fd = openat_file(dirfd, filename, O_PATH_9P_UTIL | O_NOFOLLOW, 0);
+    if (fd == -1) {
+        return -1;
+    }
+    ret = fsetxattr(fd, name, value, size, 0, flags);
+    close_preserve_errno(fd);
+    return ret;
+}
+
+/*
+ * As long as mknodat is not available on macOS, this workaround
+ * using pthread_fchdir_np is needed.
+ *
+ * Radar filed with Apple for implementing mknodat:
+ * rdar://FB9862426 (https://openradar.appspot.com/FB9862426)
+ */
+#if defined CONFIG_PTHREAD_FCHDIR_NP
+
+static int create_socket_file_at_cwd(const char *filename, mode_t mode) {
+    int fd, err;
+    struct sockaddr_un addr = {
+        .sun_family = AF_UNIX
+    };
+
+    err = snprintf(addr.sun_path, sizeof(addr.sun_path), "./%s", filename);
+    if (err < 0 || err >= sizeof(addr.sun_path)) {
+        errno = ENAMETOOLONG;
+        return -1;
+    }
+    fd = socket(PF_UNIX, SOCK_DGRAM, 0);
+    if (fd == -1) {
+        return fd;
+    }
+    err = bind(fd, (struct sockaddr *) &addr, sizeof(addr));
+    if (err == -1) {
+        goto out;
+    }
+    /*
+     * FIXME: Should rather be using descriptor-based fchmod() on the
+     * socket file descriptor above (preferably before bind() call),
+     * instead of path-based fchmodat(), to prevent concurrent transient
+     * state issues between creating the named FIFO file at bind() and
+     * delayed adjustment of permissions at fchmodat(). However currently
+     * macOS (12.x) does not support such operations on socket file
+     * descriptors yet.
+     *
+     * Filed report with Apple: FB9997731
+     */
+    err = fchmodat(AT_FDCWD, filename, mode, AT_SYMLINK_NOFOLLOW);
+out:
+    close_preserve_errno(fd);
+    return err;
+}
+
+int qemu_mknodat(int dirfd, const char *filename, mode_t mode, dev_t dev)
+{
+    int preserved_errno, err;
+
+    if (S_ISREG(mode) || !(mode & S_IFMT)) {
+        int fd = openat_file(dirfd, filename, O_CREAT, mode);
+        if (fd == -1) {
+            return fd;
+        }
+        close(fd);
+        return 0;
+    }
+    if (!pthread_fchdir_np) {
+        error_report_once("pthread_fchdir_np() not available on this version of macOS");
+        errno = ENOTSUP;
+        return -1;
+    }
+    if (pthread_fchdir_np(dirfd) < 0) {
+        return -1;
+    }
+    if (S_ISSOCK(mode)) {
+        err = create_socket_file_at_cwd(filename, mode);
+    } else {
+        err = mknod(filename, mode, dev);
+    }
+    preserved_errno = errno;
+    /* Stop using the thread-local cwd */
+    pthread_fchdir_np(-1);
+    if (err < 0) {
+        errno = preserved_errno;
+    }
+    return err;
+}
+
+#endif