[Qemu-devel] [V11 06/15] virtio-9p: Create support in chroot environment

["M. Mohan Kumar" <mohan@in.ibm.com>]

From: "M. Mohan Kumar" <mohan@in.ibm.com>

Add both chroot worker & qemu side interfaces to create regular files in
chroot environment

Signed-off-by: M. Mohan Kumar <mohan@in.ibm.com>
---
 hw/9pfs/virtio-9p-chroot-worker.c |   36 ++++++++++++++++++++++++++++++++++++
 hw/9pfs/virtio-9p-chroot.h        |    1 +
 hw/9pfs/virtio-9p-local.c         |    5 +++--
 3 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/hw/9pfs/virtio-9p-chroot-worker.c b/hw/9pfs/virtio-9p-chroot-worker.c
index 40a54b3..581bfa95a 100644
--- a/hw/9pfs/virtio-9p-chroot-worker.c
+++ b/hw/9pfs/virtio-9p-chroot-worker.c
@@ -93,6 +93,36 @@ static int chroot_do_open(V9fsFileObjectRequest *request)
     return fd;
 }
 
+/*
+ * Helper routine to create a file and return the file descriptor
+ */
+static int chroot_do_create(V9fsFileObjectRequest *request)
+{
+    uid_t cur_uid;
+    gid_t cur_gid;
+    int fd = -1;
+
+    cur_uid = geteuid();
+    cur_gid = getegid();
+
+    if (setfsuid(request->data.uid) < 0) {
+        return -errno;
+    }
+    if (setfsgid(request->data.gid) < 0) {
+        fd = -errno;
+        goto unset_uid;
+    }
+
+    fd = open(request->path.path, request->data.flags, request->data.mode);
+    if (fd < 0) {
+        fd = -errno;
+    }
+    setfsgid(cur_gid);
+unset_uid:
+    setfsuid(cur_uid);
+    return fd;
+}
+
 static void chroot_daemonize(int chroot_sock)
 {
     sigset_t sigset;
@@ -184,6 +214,12 @@ int v9fs_chroot(FsContext *fs_ctx)
                 valid_fd = 1;
             }
             break;
+        case T_CREATE:
+            retval = chroot_do_create(&request);
+            if (retval >= 0) {
+                valid_fd = 1;
+            }
+            break;
         default:
             retval = -1;
             break;
diff --git a/hw/9pfs/virtio-9p-chroot.h b/hw/9pfs/virtio-9p-chroot.h
index 326238d..d5c3f37 100644
--- a/hw/9pfs/virtio-9p-chroot.h
+++ b/hw/9pfs/virtio-9p-chroot.h
@@ -4,6 +4,7 @@
 #include "qemu_socket.h"
 /* types for V9fsFileObjectRequest */
 #define T_OPEN      1
+#define T_CREATE    2
 
 #define V9FS_FD_VALID INT_MAX
 
diff --git a/hw/9pfs/virtio-9p-local.c b/hw/9pfs/virtio-9p-local.c
index 2ae4317..2ae08e8 100644
--- a/hw/9pfs/virtio-9p-local.c
+++ b/hw/9pfs/virtio-9p-local.c
@@ -455,8 +455,7 @@ static int local_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
             serrno = errno;
             goto err_end;
         }
-    } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||
-               (fs_ctx->fs_sm == SM_NONE)) {
+    } else if (fs_ctx->fs_sm == SM_NONE) {
         fd = open(rpath(fs_ctx, path, buffer), flags, credp->fc_mode);
         if (fd == -1) {
             err = fd;
@@ -467,6 +466,8 @@ static int local_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
             serrno = errno;
             goto err_end;
         }
+    } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) {
+        fd = passthrough_request(fs_ctx, NULL, path, flags, credp, T_CREATE);
     }
     err = fd;
     goto out;
-- 
1.7.5.4