Backport FreeBSD support to the 9pfs device model

fsdev/file-op-9p.h

@@ -21,9 +21,11 @@
 
 #ifdef CONFIG_LINUX
 # include <sys/vfs.h>
-#endif
-#ifdef CONFIG_DARWIN
+#elif defined(CONFIG_DARWIN) || defined(CONFIG_BSD)
 # include <sys/param.h>
+# ifdef CONFIG_BSD
+#  undef MACHINE /* work around some unfortunate namespace pollution */
+# endif
 # include <sys/mount.h>
 #endif
 

fsdev/meson.build

@@ -8,6 +8,7 @@ fsdev_ss.add(when: ['CONFIG_FSDEV_9P'], if_true: files(
 ), if_false: files('qemu-fsdev-dummy.c'))
 softmmu_ss.add_all(when: 'CONFIG_LINUX', if_true: fsdev_ss)
 softmmu_ss.add_all(when: 'CONFIG_DARWIN', if_true: fsdev_ss)
+softmmu_ss.add_all(when: 'CONFIG_BSD', if_true: fsdev_ss)
 
 if have_virtfs_proxy_helper
   executable('virtfs-proxy-helper',

fsdev/qemu-fsdev.c

@@ -89,17 +89,6 @@ static FsDriverTable FsDrivers[] = {
             NULL
         },
     },
-    {
-        .name = "proxy",
-        .ops = &proxy_ops,
-        .opts = (const char * []) {
-            COMMON_FS_DRIVER_OPTIONS,
-            "socket",
-            "sock_fd",
-            "writeout",
-            NULL
-        },
-    },
 };
 
 static int validate_opt(void *opaque, const char *name, const char *value,

hw/9pfs/9p-posix-acl.c

@@ -65,7 +65,11 @@ static int mp_pacl_removexattr(FsContext *ctx,
     int ret;
 
     ret = local_removexattr_nofollow(ctx, path, MAP_ACL_ACCESS);
-    if (ret == -1 && errno == ENODATA) {
+    /*
+     * macOS returns ENOATTR (!=ENODATA on macOS), whereas Linux returns
+     * ENODATA (==ENOATTR on Linux), so checking for ENOATTR is fine
+     */
+    if (ret == -1 && errno == ENOATTR) {
         /*
          * We don't get ENODATA error when trying to remove a
          * posix acl that is not present. So don't throw the error
@@ -115,7 +119,11 @@ static int mp_dacl_removexattr(FsContext *ctx,
     int ret;
 
     ret = local_removexattr_nofollow(ctx, path, MAP_ACL_DEFAULT);
-    if (ret == -1 && errno == ENODATA) {
+    /*
+     * macOS returns ENOATTR (!=ENODATA on macOS), whereas Linux returns
+     * ENODATA (==ENOATTR on Linux), so checking for ENOATTR is fine
+     */
+    if (ret == -1 && errno == ENOATTR) {
         /*
          * We don't get ENODATA error when trying to remove a
          * posix acl that is not present. So don't throw the error

hw/9pfs/9p-synth.c

@@ -443,7 +443,7 @@ static int synth_statfs(FsContext *s, V9fsPath *fs_path,
     stbuf->f_bsize = 512;
     stbuf->f_blocks = 0;
     stbuf->f_files = synth_node_count;
-#ifndef CONFIG_DARWIN
+#if !defined(CONFIG_DARWIN) && !defined(CONFIG_BSD)
     stbuf->f_namelen = NAME_MAX;
 #endif
     return 0;

hw/9pfs/9p-util-freebsd.c

@@ -0,0 +1,132 @@
+/*
+ * 9p utilities (FreeBSD 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.
+ */
+
+/*
+ * Not so fast! You might want to read the 9p developer docs first:
+ * https://wiki.qemu.org/Documentation/9p
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/xattr.h"
+#include "9p-util.h"
+
+static int mangle_xattr_name(const char **namep)
+{
+    const char *name = *namep;
+
+    /*
+     * ZFS forbids attributes in starting with "user." or "system.".
+     */
+    if (strncmp(name, "system.", 7) == 0) {
+        *namep = name + 7;
+        return EXTATTR_NAMESPACE_SYSTEM;
+    }
+    if (strncmp(name, "user.", 5) == 0) {
+        *namep = name + 5;
+    }
+    return EXTATTR_NAMESPACE_USER;
+}
+
+ssize_t fgetxattr(int fd, const char *name, void *value, size_t size)
+{
+    int namespace;
+
+    namespace = mangle_xattr_name(&name);
+    return extattr_get_fd(fd, namespace, name, value, size);
+}
+
+ssize_t fgetxattrat_nofollow(int dirfd, const char *filename, const char *name,
+                             void *value, size_t size)
+{
+    ssize_t ret;
+    int fd, namespace;
+
+    fd = openat_file(dirfd, filename,
+                     O_RDONLY | O_PATH_9P_UTIL | O_NOFOLLOW, 0);
+    if (fd == -1) {
+        return -1;
+    }
+    namespace = mangle_xattr_name(&name);
+    ret = extattr_get_fd(fd, namespace, name, value, size);
+    close_preserve_errno(fd);
+    return ret;
+}
+
+ssize_t flistxattrat_nofollow(int dirfd, const char *filename,
+                              char *list, size_t size)
+{
+    ssize_t ret;
+    int fd;
+
+    fd = openat_file(dirfd, filename,
+                     O_RDONLY | O_PATH_9P_UTIL | O_NOFOLLOW, 0);
+    if (fd == -1) {
+        return -1;
+    }
+    ret = extattr_list_fd(fd, EXTATTR_NAMESPACE_USER, list, size);
+    close_preserve_errno(fd);
+    return ret;
+}
+
+ssize_t fremovexattrat_nofollow(int dirfd, const char *filename,
+                                const char *name)
+{
+    int fd, namespace, ret;
+
+    fd = openat_file(dirfd, filename,
+                     O_RDONLY | O_PATH_9P_UTIL | O_NOFOLLOW, 0);
+    if (fd == -1) {
+        return -1;
+    }
+    namespace = mangle_xattr_name(&name);
+    ret = extattr_delete_fd(fd, namespace, name);
+    close_preserve_errno(fd);
+    return ret;
+}
+
+int fsetxattrat_nofollow(int dirfd, const char *filename, const char *name,
+                         void *value, size_t size, int flags)
+{
+    ssize_t ret;
+    int fd, namespace;
+
+    namespace = mangle_xattr_name(&name);
+    if (flags == (XATTR_CREATE | XATTR_REPLACE)) {
+        errno = EINVAL;
+        return -1;
+    }
+    fd = openat_file(dirfd, filename,
+                     O_RDONLY | O_PATH_9P_UTIL | O_NOFOLLOW, 0);
+    if (fd == -1) {
+        return -1;
+    }
+    if (flags & (XATTR_CREATE | XATTR_REPLACE)) {
+        ret = extattr_get_fd(fd, namespace, name, NULL, 0);
+        if (ret == -1 && errno != ENOATTR) {
+            close_preserve_errno(fd);
+            return -1;
+        }
+        if (ret >= 0 && (flags & XATTR_CREATE)) {
+            errno = EEXIST;
+            close_preserve_errno(fd);
+            return -1;
+        }
+        if (ret == -1 && (flags & XATTR_REPLACE)) {
+            errno = ENOATTR;
+            close_preserve_errno(fd);
+            return -1;
+        }
+    }
+    ret = extattr_set_fd(fd, namespace, name, value, size);
+    close_preserve_errno(fd);
+    return ret;
+}
+
+int qemu_mknodat(int dirfd, const char *filename, mode_t mode, dev_t dev)
+{
+    return mknodat(dirfd, filename, mode, dev);
+}

hw/9pfs/9p-util.h

@@ -19,6 +19,15 @@
 #define O_PATH_9P_UTIL 0
 #endif
 
+#ifdef CONFIG_BSD
+/*
+ * FreeBSD does not have these flags, so we can only emulate their intended
+ * behaviour (racily).
+ */
+#define XATTR_CREATE    0x1
+#define XATTR_REPLACE   0x2
+#endif
+
 #ifdef CONFIG_DARWIN
 #define qemu_fgetxattr(...) fgetxattr(__VA_ARGS__, 0, 0)
 #define qemu_lgetxattr(...) getxattr(__VA_ARGS__, 0, XATTR_NOFOLLOW)
@@ -54,13 +63,13 @@ static inline int openat_file(int dirfd, const char *name, int flags,
 {
     int fd, serrno, ret;
 
-#ifndef CONFIG_DARWIN
+#if !defined(CONFIG_DARWIN) && !defined(CONFIG_BSD)
 again:
 #endif
     fd = openat(dirfd, name, flags | O_NOFOLLOW | O_NOCTTY | O_NONBLOCK,
                 mode);
     if (fd == -1) {
-#ifndef CONFIG_DARWIN
+#if !defined(CONFIG_DARWIN) && !defined(CONFIG_BSD)
         if (errno == EPERM && (flags & O_NOATIME)) {
             /*
              * The client passed O_NOATIME but we lack permissions to honor it.
@@ -90,6 +99,9 @@ static inline int openat_file(int dirfd, const char *name, int flags,
     return fd;
 }
 
+#ifdef CONFIG_BSD
+ssize_t fgetxattr(int dirfd, const char *name, void *value, size_t size);
+#endif
 ssize_t fgetxattrat_nofollow(int dirfd, const char *path, const char *name,
                              void *value, size_t size);
 int fsetxattrat_nofollow(int dirfd, const char *path, const char *name,

hw/9pfs/9p.c

@@ -138,8 +138,10 @@ static int dotl_to_open_flags(int flags)
         { P9_DOTL_NONBLOCK, O_NONBLOCK } ,
         { P9_DOTL_DSYNC, O_DSYNC },
         { P9_DOTL_FASYNC, FASYNC },
-#ifndef CONFIG_DARWIN
+#if !defined(CONFIG_DARWIN) && !defined(CONFIG_BSD)
         { P9_DOTL_NOATIME, O_NOATIME },
+#endif
+#ifndef CONFIG_DARWIN
         /*
          *  On Darwin, we could map to F_NOCACHE, which is
          *  similar, but doesn't quite have the same
@@ -3547,7 +3549,7 @@ static int v9fs_fill_statfs(V9fsState *s, V9fsPDU *pdu, struct statfs *stbuf)
     f_bavail = stbuf->f_bavail / bsize_factor;
     f_files  = stbuf->f_files;
     f_ffree  = stbuf->f_ffree;
-#ifdef CONFIG_DARWIN
+#if defined(CONFIG_DARWIN) || defined(CONFIG_BSD)
     fsid_val = (unsigned int)stbuf->f_fsid.val[0] |
                (unsigned long long)stbuf->f_fsid.val[1] << 32;
     f_namelen = NAME_MAX;
@@ -3939,6 +3941,16 @@ static void coroutine_fn v9fs_xattrwalk(void *opaque)
  * Linux guests.
  */
 #define P9_XATTR_SIZE_MAX 65536
+#elif defined(CONFIG_BSD)
+/*
+ * FreeBSD similarly doesn't define a maximum xattr size, the limit is
+ * filesystem dependent.  On UFS filesystems it's 2 times the filesystem block
+ * size, typically 32KB.  On ZFS it depends on the value of the xattr property;
+ * with the default value there is no limit, and with xattr=sa it is 64KB.
+ *
+ * So, a limit of 64k seems reasonable here too.
+ */
+#define P9_XATTR_SIZE_MAX 65536
 #else
 #error Missing definition for P9_XATTR_SIZE_MAX for this host system
 #endif

hw/9pfs/meson.build

@@ -2,7 +2,6 @@ fs_ss = ss.source_set()
 fs_ss.add(files(
   '9p-local.c',
   '9p-posix-acl.c',
-  '9p-proxy.c',
   '9p-synth.c',
   '9p-xattr-user.c',
   '9p-xattr.c',
@@ -15,6 +14,7 @@ fs_ss.add(files(
 ))
 fs_ss.add(when: 'CONFIG_LINUX', if_true: files('9p-util-linux.c'))
 fs_ss.add(when: 'CONFIG_DARWIN', if_true: files('9p-util-darwin.c'))
+fs_ss.add(when: 'CONFIG_BSD', if_true: files('9p-util-freebsd.c'))
 fs_ss.add(when: 'CONFIG_XEN', if_true: files('xen-9p-backend.c'))
 softmmu_ss.add_all(when: 'CONFIG_FSDEV_9P', if_true: fs_ss)
 

include/qemu/xattr.h

@@ -25,7 +25,11 @@
 #  if !defined(ENOATTR)
 #    define ENOATTR ENODATA
 #  endif
-#  include <sys/xattr.h>
+#  ifdef CONFIG_BSD
+#    include <sys/extattr.h>
+#  else
+#    include <sys/xattr.h>
+#  endif
 #endif
 
 #endif

meson.build

@@ -1465,16 +1465,16 @@ dbus_display = get_option('dbus_display') \
   .allowed()
 
 have_virtfs = get_option('virtfs') \
-    .require(targetos == 'linux' or targetos == 'darwin',
-             error_message: 'virtio-9p (virtfs) requires Linux or macOS') \
-    .require(targetos == 'linux' or cc.has_function('pthread_fchdir_np'),
+    .require(targetos == 'linux' or targetos == 'darwin' or targetos == 'freebsd',
+             error_message: 'virtio-9p (virtfs) requires Linux or macOS or FreeBSD') \
+    .require(targetos != 'darwin' or cc.has_function('pthread_fchdir_np'),
              error_message: 'virtio-9p (virtfs) on macOS requires the presence of pthread_fchdir_np') \
-    .require(targetos == 'darwin' or (libattr.found() and libcap_ng.found()),
+    .require(targetos != 'linux' or (libattr.found() and libcap_ng.found()),
              error_message: 'virtio-9p (virtfs) on Linux requires libcap-ng-devel and libattr-devel') \
     .disable_auto_if(not have_tools and not have_system) \
     .allowed()
 
-have_virtfs_proxy_helper = targetos != 'darwin' and have_virtfs and have_tools
+have_virtfs_proxy_helper = targetos != 'darwin' and targetos != 'freebsd' and have_virtfs and have_tools
 
 foreach k : get_option('trace_backends')
   config_host_data.set('CONFIG_TRACE_' + k.to_upper(), true)