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[Qemu-devel] [V4 PATCH 6/8] Support for creating special files
From: |
M. Mohan Kumar |
Subject: |
[Qemu-devel] [V4 PATCH 6/8] Support for creating special files |
Date: |
Tue, 1 Feb 2011 10:57:41 +0530 |
Add both server and client side interfaces to create special files
(directory, device nodes, links and symbolic links)
Signed-off-by: M. Mohan Kumar <address@hidden>
---
hw/9pfs/virtio-9p-chroot.c | 84 ++++++++++++++++++++++++++
hw/9pfs/virtio-9p-chroot.h | 2 +
hw/9pfs/virtio-9p-local.c | 141 ++++++++++++++++++++++++++++++++++----------
3 files changed, 196 insertions(+), 31 deletions(-)
diff --git a/hw/9pfs/virtio-9p-chroot.c b/hw/9pfs/virtio-9p-chroot.c
index 890dd78..85a42e6 100644
--- a/hw/9pfs/virtio-9p-chroot.c
+++ b/hw/9pfs/virtio-9p-chroot.c
@@ -227,6 +227,31 @@ static void chroot_do_open(V9fsFileObjectRequest *request,
FdInfo *fd_info)
}
}
+int v9fs_create_special(FsContext *fs_ctx,
+ V9fsFileObjectRequest *request, int *error)
+{
+ int fd;
+ pthread_mutex_lock(&fs_ctx->chroot_mutex);
+
+ if (fs_ctx->chroot_ioerror) {
+ *error = EIO;
+ goto unlock;
+ }
+ *error = 0;
+ v9fs_write_request(fs_ctx->chroot_socket, request);
+ fd = v9fs_receivefd(fs_ctx->chroot_socket, error);
+ if (fd == -EIO) {
+ fs_ctx->chroot_ioerror = 1;
+ }
+unlock:
+ pthread_mutex_unlock(&fs_ctx->chroot_mutex);
+ if (*error) {
+ return -1;
+ } else {
+ return 0;
+ }
+}
+
/*
* Helper routine to create a file and return the file descriptor and
* error status in FdInfo structure.
@@ -265,6 +290,59 @@ unset_uid:
setfsuid(cur_uid);
}
+/*
+ * Create directory, symbolic link, link, device node and regular files
+ * Similar to create, but it does not return the fd of created object
+ * Returns 0 on success, returns errno on failure
+ */
+static void chroot_do_create_special(V9fsFileObjectRequest *request,
+ FdInfo *fd_info)
+{
+ int cur_uid, cur_gid;
+
+ cur_uid = geteuid();
+ cur_gid = getegid();
+
+ fd_info->fi_fd = -1;
+ fd_info->fi_error = 0;
+
+ if (setfsuid(request->data.uid) < 0) {
+ fd_info->fi_error = errno;
+ return;
+ }
+ if (setfsgid(request->data.gid) < 0) {
+ fd_info->fi_error = errno;
+ goto unset_uid;
+ }
+
+ switch (request->data.type) {
+ case T_MKDIR:
+ fd_info->fi_fd = mkdir(request->path.path, request->data.mode);
+ break;
+ case T_SYMLINK:
+ fd_info->fi_fd = symlink(request->path.old_path, request->path.path);
+ break;
+ case T_LINK:
+ fd_info->fi_fd = link(request->path.old_path, request->path.path);
+ break;
+ default:
+ fd_info->fi_fd = mknod(request->path.path, request->data.mode,
+ request->data.dev);
+ break;
+ }
+
+ if (fd_info->fi_fd < 0) {
+ fd_info->fi_error = errno;
+ } else {
+ fd_info->fi_error = 0;
+ fd_info->fi_fd = -1;
+ }
+
+ setfsgid(cur_gid);
+unset_uid:
+ setfsuid(cur_uid);
+}
+
static int chroot_daemonize(int chroot_sock)
{
sigset_t sigset;
@@ -365,6 +443,12 @@ int v9fs_chroot(FsContext *fs_ctx)
case T_CREATE:
chroot_do_create(&request, &fd_info);
break;
+ case T_MKDIR:
+ case T_SYMLINK:
+ case T_LINK:
+ case T_MKNOD:
+ chroot_do_create_special(&request, &fd_info);
+ break;
default:
fd_info.fi_fd = 0;
fd_info.fi_error = EIO;
diff --git a/hw/9pfs/virtio-9p-chroot.h b/hw/9pfs/virtio-9p-chroot.h
index ffeeddc..c7ebb47 100644
--- a/hw/9pfs/virtio-9p-chroot.h
+++ b/hw/9pfs/virtio-9p-chroot.h
@@ -38,5 +38,7 @@ typedef struct V9fsFileObjectRequest
int v9fs_chroot(FsContext *fs_ctx);
int v9fs_request(FsContext *fs_ctx, V9fsFileObjectRequest *or, int *error);
+int v9fs_create_special(FsContext *fs_ctx,
+ V9fsFileObjectRequest *request, int *error);
#endif /* _QEMU_VIRTIO_9P_CHROOT_H */
diff --git a/hw/9pfs/virtio-9p-local.c b/hw/9pfs/virtio-9p-local.c
index afb088a..c9ece6b 100644
--- a/hw/9pfs/virtio-9p-local.c
+++ b/hw/9pfs/virtio-9p-local.c
@@ -69,6 +69,78 @@ static int passthrough_create(FsContext *fs_ctx, const char
*path, int flags,
return fd;
}
+static int passthrough_mknod(FsContext *fs_ctx, const char *path, FsCred
*credp)
+{
+ V9fsFileObjectRequest request;
+ int retval, error = 0;
+
+ fill_request(&request, path, credp);
+ request.data.type = T_MKNOD;
+
+ retval = v9fs_create_special(fs_ctx, &request, &error);
+ if (retval < 0) {
+ errno = error;
+ }
+ return retval;
+}
+
+static int passthrough_mkdir(FsContext *fs_ctx, const char *path, FsCred
*credp)
+{
+ V9fsFileObjectRequest request;
+ int retval, error = 0;
+
+ fill_request(&request, path, credp);
+ request.data.type = T_MKDIR;
+
+ retval = v9fs_create_special(fs_ctx, &request, &error);
+ if (retval < 0) {
+ errno = error;
+ }
+ qemu_free((void *)request.path.path);
+ return retval;
+}
+
+static int passthrough_symlink(FsContext *fs_ctx, const char *oldpath,
+ const char *newpath, FsCred *credp)
+{
+ V9fsFileObjectRequest request;
+ int retval, error = 0;
+
+ fill_request(&request, newpath, credp);
+ request.data.type = T_SYMLINK;
+ request.data.oldpath_len = strlen(oldpath);
+ request.path.old_path = qemu_strdup(oldpath);
+
+ retval = v9fs_create_special(fs_ctx, &request, &error);
+ if (retval > 0) {
+ errno = error;
+ return 0;
+ }
+ qemu_free((void *)request.path.old_path);
+ qemu_free((void *)request.path.path);
+ return retval;
+}
+
+static int passthrough_link(FsContext *fs_ctx, const char *oldpath,
+ const char *newpath)
+{
+ V9fsFileObjectRequest request;
+ int retval, error = 0;
+
+ fill_request(&request, newpath, NULL);
+ request.data.type = T_LINK;
+ request.data.oldpath_len = strlen(oldpath);
+ request.path.old_path = qemu_strdup(oldpath);
+ retval = v9fs_create_special(fs_ctx, &request, &error);
+ if (retval > 0) {
+ errno = error;
+ return 0;
+ }
+ qemu_free((void *)request.path.old_path);
+ qemu_free((void *)request.path.path);
+ return retval;
+}
+
static int local_lstat(FsContext *fs_ctx, const char *path, struct stat *stbuf)
{
int err;
@@ -286,8 +358,7 @@ static int local_mknod(FsContext *fs_ctx, const char *path,
FsCred *credp)
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) {
err = mknod(rpath(fs_ctx, path), credp->fc_mode, credp->fc_rdev);
if (err == -1) {
return err;
@@ -297,6 +368,12 @@ static int local_mknod(FsContext *fs_ctx, const char
*path, FsCred *credp)
serrno = errno;
goto err_end;
}
+ } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) {
+ err = passthrough_mknod(fs_ctx, path, credp);
+ if (err < 0) {
+ serrno = errno;
+ goto err_end;
+ }
}
return err;
@@ -323,8 +400,7 @@ static int local_mkdir(FsContext *fs_ctx, const char *path,
FsCred *credp)
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) {
err = mkdir(rpath(fs_ctx, path), credp->fc_mode);
if (err == -1) {
return err;
@@ -334,6 +410,12 @@ static int local_mkdir(FsContext *fs_ctx, const char
*path, FsCred *credp)
serrno = errno;
goto err_end;
}
+ } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) {
+ err = passthrough_mkdir(fs_ctx, path, credp);
+ if (err < 0) {
+ serrno = errno;
+ goto err_end;
+ }
}
return err;
@@ -451,23 +533,18 @@ static int local_symlink(FsContext *fs_ctx, const char
*oldpath,
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) {
err = symlink(oldpath, rpath(fs_ctx, newpath));
if (err) {
return err;
}
err = lchown(rpath(fs_ctx, newpath), credp->fc_uid, credp->fc_gid);
- if (err == -1) {
- /*
- * If we fail to change ownership and if we are
- * using security model none. Ignore the error
- */
- if (fs_ctx->fs_sm != SM_NONE) {
- serrno = errno;
- goto err_end;
- } else
- err = 0;
+ err = 0;
+ } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) {
+ err = passthrough_symlink(fs_ctx, oldpath, newpath, credp);
+ if (err < 0) {
+ serrno = errno;
+ goto err_end;
}
}
return err;
@@ -478,24 +555,26 @@ err_end:
return err;
}
-static int local_link(FsContext *ctx, const char *oldpath, const char *newpath)
+static int local_link(FsContext *fs_ctx, const char *oldpath,
+ const char *newpath)
{
- char *tmp = qemu_strdup(rpath(ctx, oldpath));
int err, serrno = 0;
- if (tmp == NULL) {
- return -ENOMEM;
- }
-
- err = link(tmp, rpath(ctx, newpath));
- if (err == -1) {
- serrno = errno;
- }
-
- qemu_free(tmp);
-
- if (err == -1) {
- errno = serrno;
+ if (fs_ctx->fs_sm == SM_PASSTHROUGH) {
+ err = passthrough_link(fs_ctx, oldpath, newpath);
+ if (err < 0) {
+ serrno = errno;
+ }
+ } else {
+ char *tmp = qemu_strdup(rpath(fs_ctx, oldpath));
+ if (tmp == NULL) {
+ return -ENOMEM;
+ }
+ err = link(tmp, rpath(fs_ctx, newpath));
+ if (err == -1) {
+ serrno = errno;
+ }
+ qemu_free(tmp);
}
return err;
--
1.7.3.4
- Re: [Qemu-devel] [V4 PATCH 2/8] Provide chroot environment server side interfaces, (continued)
[Qemu-devel] [V4 PATCH 3/8] Add client side interfaces for chroot environment, M. Mohan Kumar, 2011/02/01
[Qemu-devel] [V4 PATCH 4/8] Add support to open a file in chroot environment, M. Mohan Kumar, 2011/02/01
[Qemu-devel] [V4 PATCH 5/8] Create support in chroot environment, M. Mohan Kumar, 2011/02/01
[Qemu-devel] [V4 PATCH 6/8] Support for creating special files,
M. Mohan Kumar <=
[Qemu-devel] [V4 PATCH 7/8] Move file post creation changes to none security model, M. Mohan Kumar, 2011/02/01
[Qemu-devel] [V4 PATCH 8/8] Chroot environment for other functions, M. Mohan Kumar, 2011/02/01