[Qemu-devel] [PATCH 10/13] 9p: introduce fchmod file op

[Greg Kurz]

This allows fchmod() in the guest to stay functional even if the file
was unlinked.

Signed-off-by: Greg Kurz <address@hidden>
---
 fsdev/file-op-9p.h  |    1 +
 hw/9pfs/9p-handle.c |   10 ++++++++++
 hw/9pfs/9p-local.c  |   21 +++++++++++++++++++++
 hw/9pfs/9p-proxy.c  |   10 ++++++++++
 hw/9pfs/9p-synth.c  |    8 ++++++++
 hw/9pfs/9p.c        |   20 ++++++++++++++++----
 hw/9pfs/cofs.c      |   21 +++++++++++++++++++++
 hw/9pfs/coth.h      |    1 +
 8 files changed, 88 insertions(+), 4 deletions(-)

diff --git a/fsdev/file-op-9p.h b/fsdev/file-op-9p.h
index 1c15d6efdaea..8094d2c6c438 100644
--- a/fsdev/file-op-9p.h
+++ b/fsdev/file-op-9p.h
@@ -144,6 +144,7 @@ struct FileOperations
     int (*futimens)(FsContext *, int, V9fsFidOpenState *,
                     const struct timespec *);
     int (*fchown)(FsContext *, int, V9fsFidOpenState *, FsCred *);
+    int (*fchmod)(FsContext *, int, V9fsFidOpenState *, FsCred *);
     void *opaque;
 };
 
diff --git a/hw/9pfs/9p-handle.c b/hw/9pfs/9p-handle.c
index 7e8e776cdab0..f345217aa8e1 100644
--- a/hw/9pfs/9p-handle.c
+++ b/hw/9pfs/9p-handle.c
@@ -218,6 +218,15 @@ static int handle_chmod(FsContext *fs_ctx, V9fsPath 
*fs_path, FsCred *credp)
     return ret;
 }
 
+static int handle_fchmod(FsContext *fs_ctx, int fid_type, V9fsFidOpenState *fs,
+                         FsCred *credp)
+{
+    int fd;
+
+    fd = v9fs_get_fd_fid(fid_type, fs);
+    return fchmod(fd, credp->fc_mode);
+}
+
 static int handle_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
                        const char *name, FsCred *credp)
 {
@@ -726,4 +735,5 @@ FileOperations handle_ops = {
     .ftruncate    = handle_ftruncate,
     .futimens     = handle_futimens,
     .fchown       = handle_fchown,
+    .fchmod       = handle_fchmod,
 };
diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index bc8d3bff1308..e51c58037266 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -516,6 +516,26 @@ static int local_chmod(FsContext *fs_ctx, V9fsPath 
*fs_path, FsCred *credp)
     return ret;
 }
 
+static int local_fchmod(FsContext *fs_ctx, int fid_type, V9fsFidOpenState *fs,
+                        FsCred *credp)
+{
+    int ret = -1;
+    int fd;
+
+    fd = v9fs_get_fd_fid(fid_type, fs);
+
+    if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
+        ret = local_set_xattr(fd, NULL, credp);
+    } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
+        errno = ENOTSUP;
+        return -1;
+    } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
+               (fs_ctx->export_flags & V9FS_SM_NONE)) {
+        ret = fchmod(fd, credp->fc_mode);
+    }
+    return ret;
+}
+
 static int local_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
                        const char *name, FsCred *credp)
 {
@@ -1336,4 +1356,5 @@ FileOperations local_ops = {
     .ftruncate = local_ftruncate,
     .futimens = local_futimens,
     .fchown = local_fchown,
+    .fchmod = local_fchmod,
 };
diff --git a/hw/9pfs/9p-proxy.c b/hw/9pfs/9p-proxy.c
index 8f2e27c6f8e4..dec4a861a073 100644
--- a/hw/9pfs/9p-proxy.c
+++ b/hw/9pfs/9p-proxy.c
@@ -743,6 +743,15 @@ static int proxy_chmod(FsContext *fs_ctx, V9fsPath 
*fs_path, FsCred *credp)
     return retval;
 }
 
+static int proxy_fchmod(FsContext *fs_ctx, int fid_type, V9fsFidOpenState *fs,
+                        FsCred *credp)
+{
+    int fd;
+
+    fd = v9fs_get_fd_fid(fid_type, fs);
+    return fchmod(fd, credp->fc_mode);
+}
+
 static int proxy_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
                        const char *name, FsCred *credp)
 {
@@ -1241,4 +1250,5 @@ FileOperations proxy_ops = {
     .ftruncate    = proxy_ftruncate,
     .futimens     = proxy_futimens,
     .fchown       = proxy_fchown,
+    .fchmod       = proxy_fchmod,
 };
diff --git a/hw/9pfs/9p-synth.c b/hw/9pfs/9p-synth.c
index b0f9b0cd67f6..ec2e301de8c6 100644
--- a/hw/9pfs/9p-synth.c
+++ b/hw/9pfs/9p-synth.c
@@ -357,6 +357,13 @@ static int synth_chmod(FsContext *fs_ctx, V9fsPath *path, 
FsCred *credp)
     return -1;
 }
 
+static int synth_fchmod(FsContext *fs_ctx, int fid_type, V9fsFidOpenState *fs,
+                        FsCred *credp)
+{
+    errno = EPERM;
+    return -1;
+}
+
 static int synth_mknod(FsContext *fs_ctx, V9fsPath *path,
                        const char *buf, FsCred *credp)
 {
@@ -590,4 +597,5 @@ FileOperations synth_ops = {
     .ftruncate    = synth_ftruncate,
     .futimens     = synth_futimens,
     .fchown       = synth_fchown,
+    .fchmod       = synth_fchmod,
 };
diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index 351bbdde4748..8824b71f364b 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -1221,6 +1221,19 @@ static int v9fs_do_chown(V9fsPDU *pdu, V9fsFidState 
*fidp, uid_t uid, gid_t gid)
     return err;
 }
 
+static int v9fs_do_chmod(V9fsPDU *pdu, V9fsFidState *fidp, mode_t mode)
+{
+    int err;
+
+    if (fid_has_file(fidp)) {
+        err = v9fs_co_fchmod(pdu, fidp, mode);
+    } else {
+        err = v9fs_co_chmod(pdu, &fidp->path, mode);
+    }
+
+    return err;
+}
+
 /* Attribute flags */
 #define P9_ATTR_MODE       (1 << 0)
 #define P9_ATTR_UID        (1 << 1)
@@ -1254,7 +1267,7 @@ static void v9fs_setattr(void *opaque)
         goto out_nofid;
     }
     if (v9iattr.valid & P9_ATTR_MODE) {
-        err = v9fs_co_chmod(pdu, &fidp->path, v9iattr.mode);
+        err = v9fs_do_chmod(pdu, fidp, v9iattr.mode);
         if (err < 0) {
             goto out;
         }
@@ -2754,9 +2767,8 @@ static void v9fs_wstat(void *opaque)
             err = -EIO;
             goto out;
         }
-        err = v9fs_co_chmod(pdu, &fidp->path,
-                            v9mode_to_mode(v9stat.mode,
-                                           &v9stat.extension));
+        err = v9fs_do_chmod(pdu, fidp, v9mode_to_mode(v9stat.mode,
+                                                      &v9stat.extension));
         if (err < 0) {
             goto out;
         }
diff --git a/hw/9pfs/cofs.c b/hw/9pfs/cofs.c
index 4e8fbbe2b24e..779997dc0e33 100644
--- a/hw/9pfs/cofs.c
+++ b/hw/9pfs/cofs.c
@@ -112,6 +112,27 @@ int v9fs_co_chmod(V9fsPDU *pdu, V9fsPath *path, mode_t 
mode)
     return err;
 }
 
+int v9fs_co_fchmod(V9fsPDU *pdu, V9fsFidState *fidp, mode_t mode)
+{
+    int err;
+    FsCred cred;
+    V9fsState *s = pdu->s;
+
+    if (v9fs_request_cancelled(pdu)) {
+        return -EINTR;
+    }
+    cred_init(&cred);
+    cred.fc_mode = mode;
+    v9fs_co_run_in_worker(
+        {
+            err = s->ops->fchmod(&s->ctx, fidp->fid_type, &fidp->fs, &cred);
+            if (err < 0) {
+                err = -errno;
+            }
+        });
+    return err;
+}
+
 int v9fs_co_utimensat(V9fsPDU *pdu, V9fsPath *path,
                       struct timespec times[2])
 {
diff --git a/hw/9pfs/coth.h b/hw/9pfs/coth.h
index 7050298f7170..ee819a7eed54 100644
--- a/hw/9pfs/coth.h
+++ b/hw/9pfs/coth.h
@@ -97,5 +97,6 @@ extern int v9fs_co_st_gen(V9fsPDU *pdu, V9fsPath *path, 
mode_t,
 extern int v9fs_co_ftruncate(V9fsPDU *, V9fsFidState *, off_t);
 extern int v9fs_co_futimens(V9fsPDU *, V9fsFidState *, struct timespec [2]);
 extern int v9fs_co_fchown(V9fsPDU *, V9fsFidState *, uid_t, gid_t);
+extern int v9fs_co_fchmod(V9fsPDU *, V9fsFidState *, mode_t);
 
 #endif