* [PULL 1/2] 9pfs: Add FreeBSD support
2025-09-18 19:42 [PULL 0/2] 9p queue 2025-09-18 Christian Schoenebeck
2025-09-18 19:42 ` [PULL 2/2] 9pfs: Stop including gstrfuncs.h Christian Schoenebeck
@ 2025-09-18 19:42 ` Christian Schoenebeck
2025-09-19 20:47 ` [PULL 0/2] 9p queue 2025-09-18 Richard Henderson
2 siblings, 0 replies; 4+ messages in thread
From: Christian Schoenebeck @ 2025-09-18 19:42 UTC (permalink / raw)
To: qemu-devel; +Cc: Greg Kurz, Mark Johnston
From: Mark Johnston <markj@freebsd.org>
This is largely derived from existing Darwin support. FreeBSD
apparently has better support for *at() system calls so doesn't require
workarounds for a missing mknodat(). The implementation has a couple of
warts however:
- The extattr(2) system calls don't support anything akin to
XATTR_CREATE or XATTR_REPLACE, so a racy workaround is implemented.
- Attribute names cannot begin with "user." or "system." on ZFS.
However FreeBSD's extattr(2) system calls support two dedicated
namespaces for these two. So "user." or "system." prefixes are
trimmed off from attribute names and instead EXTATTR_NAMESPACE_USER or
EXTATTR_NAMESPACE_SYSTEM are picked and passed to extattr system calls
accordingly.
The 9pfs tests were verified to pass on the UFS, ZFS and tmpfs
filesystems.
Signed-off-by: Mark Johnston <markj@FreeBSD.org>
Link: https://lore.kernel.org/qemu-devel/aJOWhHB2p-fbueAm@nuc
Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
---
fsdev/file-op-9p.h | 6 +-
fsdev/meson.build | 2 +-
hw/9pfs/9p-synth.c | 2 +-
hw/9pfs/9p-util-freebsd.c | 132 ++++++++++++++++++++++++++++++++++++++
hw/9pfs/9p-util.h | 20 ++++--
hw/9pfs/9p.c | 16 ++++-
hw/9pfs/meson.build | 2 +
include/qemu/xattr.h | 6 +-
meson.build | 8 +--
9 files changed, 179 insertions(+), 15 deletions(-)
create mode 100644 hw/9pfs/9p-util-freebsd.c
diff --git a/fsdev/file-op-9p.h b/fsdev/file-op-9p.h
index b9dae8c84c..b85c9934de 100644
--- a/fsdev/file-op-9p.h
+++ b/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_FREEBSD)
# include <sys/param.h>
+# ifdef CONFIG_FREEBSD
+# undef MACHINE /* work around some unfortunate namespace pollution */
+# endif
# include <sys/mount.h>
#endif
diff --git a/fsdev/meson.build b/fsdev/meson.build
index c751d8cb62..95fe816604 100644
--- a/fsdev/meson.build
+++ b/fsdev/meson.build
@@ -5,6 +5,6 @@ fsdev_ss.add(when: ['CONFIG_FSDEV_9P'], if_true: files(
'9p-marshal.c',
'qemu-fsdev.c',
), if_false: files('qemu-fsdev-dummy.c'))
-if host_os in ['linux', 'darwin']
+if host_os in ['linux', 'darwin', 'freebsd']
system_ss.add_all(fsdev_ss)
endif
diff --git a/hw/9pfs/9p-synth.c b/hw/9pfs/9p-synth.c
index 9cd1884224..b3743f6169 100644
--- a/hw/9pfs/9p-synth.c
+++ b/hw/9pfs/9p-synth.c
@@ -451,7 +451,7 @@ 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_FREEBSD)
stbuf->f_namelen = NAME_MAX;
#endif
return 0;
diff --git a/hw/9pfs/9p-util-freebsd.c b/hw/9pfs/9p-util-freebsd.c
new file mode 100644
index 0000000000..9dd1d069f6
--- /dev/null
+++ b/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);
+}
diff --git a/hw/9pfs/9p-util.h b/hw/9pfs/9p-util.h
index a1924fe3f0..8dfa803dc2 100644
--- a/hw/9pfs/9p-util.h
+++ b/hw/9pfs/9p-util.h
@@ -21,6 +21,15 @@
#define O_PATH_9P_UTIL 0
#endif
+#ifdef CONFIG_FREEBSD
+/*
+ * FreeBSD does not have these flags, so we can only emulate their intended
+ * behaviour (racily).
+ */
+#define XATTR_CREATE 0x1
+#define XATTR_REPLACE 0x2
+#endif
+
#if !defined(CONFIG_LINUX)
/*
@@ -64,9 +73,9 @@ static inline uint64_t host_dev_to_dotl_dev(dev_t dev)
static inline int errno_to_dotl(int err) {
#if defined(CONFIG_LINUX)
/* nothing to translate (Linux -> Linux) */
-#elif defined(CONFIG_DARWIN)
+#elif defined(CONFIG_DARWIN) || defined(CONFIG_FREEBSD)
/*
- * translation mandatory for macOS hosts
+ * translation mandatory for non-Linux hosts
*
* FIXME: Only most important errnos translated here yet, this should be
* extended to as many errnos being translated as possible in future.
@@ -155,13 +164,13 @@ 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_FREEBSD)
again:
#endif
fd = qemu_openat(dirfd, name, flags | O_NOFOLLOW | O_NOCTTY | O_NONBLOCK,
mode);
if (fd == -1) {
-#ifndef CONFIG_DARWIN
+#if !defined(CONFIG_DARWIN) && !defined(CONFIG_FREEBSD)
if (errno == EPERM && (flags & O_NOATIME)) {
/*
* The client passed O_NOATIME but we lack permissions to honor it.
@@ -202,6 +211,9 @@ again:
return fd;
}
+#ifdef CONFIG_FREEBSD
+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,
diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index acfa7db4e1..bc4a016ee3 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -136,8 +136,10 @@ 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_FREEBSD)
{ 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
@@ -3658,7 +3660,7 @@ 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_FREEBSD)
fsid_val = (unsigned int)stbuf->f_fsid.val[0] |
(unsigned long long)stbuf->f_fsid.val[1] << 32;
f_namelen = NAME_MAX;
@@ -4050,6 +4052,16 @@ out_nofid:
* Linux guests.
*/
#define P9_XATTR_SIZE_MAX 65536
+#elif defined(CONFIG_FREEBSD)
+/*
+ * 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
diff --git a/hw/9pfs/meson.build b/hw/9pfs/meson.build
index d35d4f44ff..7f4d6e3a45 100644
--- a/hw/9pfs/meson.build
+++ b/hw/9pfs/meson.build
@@ -15,6 +15,8 @@ fs_ss.add(files(
))
if host_os == 'darwin'
fs_ss.add(files('9p-util-darwin.c'))
+elif host_os == 'freebsd'
+ fs_ss.add(files('9p-util-freebsd.c'))
elif host_os == 'linux'
fs_ss.add(files('9p-util-linux.c'))
endif
diff --git a/include/qemu/xattr.h b/include/qemu/xattr.h
index b08a934acc..224ba1276e 100644
--- a/include/qemu/xattr.h
+++ b/include/qemu/xattr.h
@@ -26,7 +26,11 @@
# define ENOATTR ENODATA
# endif
# ifndef CONFIG_WIN32
-# include <sys/xattr.h>
+# ifdef CONFIG_FREEBSD
+# include <sys/extattr.h>
+# else
+# include <sys/xattr.h>
+# endif
# endif
#endif
diff --git a/meson.build b/meson.build
index 6ade30f36a..72da97829a 100644
--- a/meson.build
+++ b/meson.build
@@ -2384,11 +2384,11 @@ dbus_display = get_option('dbus_display') \
.allowed()
have_virtfs = get_option('virtfs') \
- .require(host_os == 'linux' or host_os == 'darwin',
- error_message: 'virtio-9p (virtfs) requires Linux or macOS') \
- .require(host_os == 'linux' or cc.has_function('pthread_fchdir_np'),
+ .require(host_os == 'linux' or host_os == 'darwin' or host_os == 'freebsd',
+ error_message: 'virtio-9p (virtfs) requires Linux or macOS or FreeBSD') \
+ .require(host_os != 'darwin' or cc.has_function('pthread_fchdir_np'),
error_message: 'virtio-9p (virtfs) on macOS requires the presence of pthread_fchdir_np') \
- .require(host_os == 'darwin' or libattr.found(),
+ .require(host_os != 'linux' or libattr.found(),
error_message: 'virtio-9p (virtfs) on Linux requires libattr-devel') \
.disable_auto_if(not have_tools and not have_system) \
.allowed()
--
2.39.5
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