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[Qemu-devel] [PATCH 2/2] hw/9pfs: Read-only support for 9p export
From: |
M. Mohan Kumar |
Subject: |
[Qemu-devel] [PATCH 2/2] hw/9pfs: Read-only support for 9p export |
Date: |
Wed, 19 Oct 2011 22:46:33 +0530 |
From: "M. Mohan Kumar" <address@hidden>
A new fsdev parameter "readonly" is introduced to control accessing 9p export.
readonly=on|off can be used to specify the access type. By default rw access
is given to 9p export.
Signed-off-by: M. Mohan Kumar <address@hidden>
---
Changes from previous version V4:
* Updated on top of current for-upstream branch
Changes from previous version V3:
* Use opt_set_bool function to set readonly option
* Change the flag from MS_READONLY to 9p specific
Change from previous version V2:
* QEMU_OPT_BOOL is used for readdonly parameter
Changes from previous version:
* Use "readonly" option instead of "access"
* Change function return type to boolean where its needed
fsdev/file-op-9p.h | 2 ++
fsdev/qemu-fsdev.c | 7 ++++++-
hw/9pfs/virtio-9p.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
qemu-config.c | 7 +++++++
vl.c | 2 ++
5 files changed, 68 insertions(+), 1 deletions(-)
diff --git a/fsdev/file-op-9p.h b/fsdev/file-op-9p.h
index c7b4e38..ba564d4 100644
--- a/fsdev/file-op-9p.h
+++ b/fsdev/file-op-9p.h
@@ -60,6 +60,8 @@ typedef struct extended_ops {
#define V9FS_SEC_MASK 0x0000001C
+#define V9FS_RDONLY 0x00000020
+
typedef struct FsContext
{
uid_t uid;
diff --git a/fsdev/qemu-fsdev.c b/fsdev/qemu-fsdev.c
index e8dc0fd..7fd2aa7 100644
--- a/fsdev/qemu-fsdev.c
+++ b/fsdev/qemu-fsdev.c
@@ -36,7 +36,7 @@ int qemu_fsdev_add(QemuOpts *opts)
const char *path = qemu_opt_get(opts, "path");
const char *sec_model = qemu_opt_get(opts, "security_model");
const char *writeout = qemu_opt_get(opts, "writeout");
-
+ bool ro = qemu_opt_get_bool(opts, "readonly", 0);
if (!fsdev_id) {
fprintf(stderr, "fsdev: No id specified\n");
@@ -87,6 +87,11 @@ int qemu_fsdev_add(QemuOpts *opts)
fsle->fse.export_flags |= V9FS_IMMEDIATE_WRITEOUT;
}
}
+ if (ro) {
+ fsle->fse.export_flags |= V9FS_RDONLY;
+ } else {
+ fsle->fse.export_flags &= ~V9FS_RDONLY;
+ }
if (strcmp(fsdriver, "local")) {
goto done;
diff --git a/hw/9pfs/virtio-9p.c b/hw/9pfs/virtio-9p.c
index 1c67bfe..b6770e2 100644
--- a/hw/9pfs/virtio-9p.c
+++ b/hw/9pfs/virtio-9p.c
@@ -1271,6 +1271,11 @@ static void v9fs_fix_path(V9fsPath *dst, V9fsPath *src,
int len)
dst->size++;
}
+static inline bool is_ro_export(int export_flags)
+{
+ return export_flags & V9FS_RDONLY;
+}
+
static void v9fs_version(void *opaque)
{
V9fsPDU *pdu = opaque;
@@ -1692,6 +1697,15 @@ static void v9fs_open(void *opaque)
} else {
flags = omode_to_uflags(mode);
}
+ if (is_ro_export(s->ctx.export_flags)) {
+ if (mode & O_WRONLY || mode & O_RDWR ||
+ mode & O_APPEND || mode & O_TRUNC) {
+ err = -EROFS;
+ goto out;
+ } else {
+ flags |= O_NOATIME;
+ }
+ }
err = v9fs_co_open(pdu, fidp, flags);
if (err < 0) {
goto out;
@@ -3311,6 +3325,39 @@ static void v9fs_op_not_supp(void *opaque)
complete_pdu(pdu->s, pdu, -EOPNOTSUPP);
}
+static void v9fs_fs_ro(void *opaque)
+{
+ V9fsPDU *pdu = opaque;
+ complete_pdu(pdu->s, pdu, -EROFS);
+}
+
+static inline bool is_read_only_op(int id)
+{
+ switch (id) {
+ case P9_TREADDIR:
+ case P9_TSTATFS:
+ case P9_TGETATTR:
+ case P9_TXATTRWALK:
+ case P9_TLOCK:
+ case P9_TGETLOCK:
+ case P9_TREADLINK:
+ case P9_TVERSION:
+ case P9_TLOPEN:
+ case P9_TATTACH:
+ case P9_TSTAT:
+ case P9_TWALK:
+ case P9_TCLUNK:
+ case P9_TFSYNC:
+ case P9_TOPEN:
+ case P9_TREAD:
+ case P9_TAUTH:
+ case P9_TFLUSH:
+ return 1;
+ default:
+ return 0;
+ }
+}
+
static void submit_pdu(V9fsState *s, V9fsPDU *pdu)
{
Coroutine *co;
@@ -3322,6 +3369,10 @@ static void submit_pdu(V9fsState *s, V9fsPDU *pdu)
} else {
handler = pdu_co_handlers[pdu->id];
}
+
+ if (is_ro_export(s->ctx.export_flags) && !is_read_only_op(pdu->id)) {
+ handler = v9fs_fs_ro;
+ }
co = qemu_coroutine_create(handler);
qemu_coroutine_enter(co, pdu);
}
diff --git a/qemu-config.c b/qemu-config.c
index 90b6b3e..597d7e1 100644
--- a/qemu-config.c
+++ b/qemu-config.c
@@ -180,7 +180,11 @@ QemuOptsList qemu_fsdev_opts = {
}, {
.name = "writeout",
.type = QEMU_OPT_STRING,
+ }, {
+ .name = "readonly",
+ .type = QEMU_OPT_BOOL,
},
+
{ /*End of list */ }
},
};
@@ -205,6 +209,9 @@ QemuOptsList qemu_virtfs_opts = {
}, {
.name = "writeout",
.type = QEMU_OPT_STRING,
+ }, {
+ .name = "readonly",
+ .type = QEMU_OPT_BOOL,
},
{ /*End of list */ }
diff --git a/vl.c b/vl.c
index c9de124..cf66ef9 100644
--- a/vl.c
+++ b/vl.c
@@ -2823,6 +2823,8 @@ int main(int argc, char **argv, char **envp)
qemu_opt_set(fsdev, "security_model",
qemu_opt_get(opts, "security_model"));
+ qemu_opt_set_bool(fsdev, "readonly",
+ qemu_opt_get_bool(opts, "readonly", 0));
device = qemu_opts_create(qemu_find_opts("device"), NULL, 0);
qemu_opt_set(device, "driver", "virtio-9p-pci");
qemu_opt_set(device, "fsdev",
--
1.7.6