This patch adds both server and client side support to open a file (directory) in the chroot environment
Signed-off-by: M. Mohan Kumar <mo...@in.ibm.com> --- hw/9pfs/virtio-9p-chroot.c | 53 ++++++++++++++++++++++++++++++++++++++----- hw/9pfs/virtio-9p-chroot.h | 1 + hw/9pfs/virtio-9p-local.c | 52 +++++++++++++++++++++++++++++++++++++++--- 3 files changed, 95 insertions(+), 11 deletions(-) diff --git a/hw/9pfs/virtio-9p-chroot.c b/hw/9pfs/virtio-9p-chroot.c index b466d9a..7da0702 100644 --- a/hw/9pfs/virtio-9p-chroot.c +++ b/hw/9pfs/virtio-9p-chroot.c @@ -191,6 +191,42 @@ static int v9fs_write_request(int sockfd, V9fsFileObjectRequest *request) return 0; } +/* Return opened file descriptor on success or -1 on error */ +int v9fs_request(FsContext *fs_ctx, V9fsFileObjectRequest *request, + int *error) +{ + int fd; + pthread_mutex_lock(&fs_ctx->chroot_mutex); + if (fs_ctx->chroot_ioerror) { + *error = EIO; + fd = -1; + goto unlock; + } + 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); + return fd; +} + +/* + * Helper routine to open a file and return fd and error status in + * FdInfo structure + */ +static void chroot_do_open(V9fsFileObjectRequest *request, FdInfo *fd_info) +{ + fd_info->fi_fd = open(request->path.path, request->data.flags); + if (fd_info->fi_fd < 0) { + fd_info->fi_error = errno; + } else { + fd_info->fi_error = 0; + fd_info->fi_flags = FI_FDVALID; + } +} + static int chroot_daemonize(int chroot_sock) { sigset_t sigset; @@ -219,12 +255,6 @@ static int chroot_daemonize(int chroot_sock) return 0; } -static void chroot_dummy(void) -{ - (void)v9fs_receivefd; - (void)v9fs_write_request; -} - /* * Fork a process and chroot into the share path. Communication * between qemu process and chroot process happens via socket @@ -270,7 +300,6 @@ int v9fs_chroot(FsContext *fs_ctx) error = qemu_write_full(chroot_sock, &code, sizeof(code)); _exit(1); } - chroot_dummy(); /* * Write 0 to chroot socket to indicate chroot process creation is @@ -291,6 +320,16 @@ int v9fs_chroot(FsContext *fs_ctx) chroot_sendfd(chroot_sock, &fd_info); continue; } + switch (request.data.type) { + case T_OPEN: + chroot_do_open(&request, &fd_info); + break; + default: + fd_info.fi_fd = 0; + fd_info.fi_error = EIO; + break; + } + chroot_sendfd(chroot_sock, &fd_info); qemu_free((void *)request.path.path); if (request.data.oldpath_len) { qemu_free((void *)request.path.old_path); diff --git a/hw/9pfs/virtio-9p-chroot.h b/hw/9pfs/virtio-9p-chroot.h index 6f3fd14..ffeeddc 100644 --- a/hw/9pfs/virtio-9p-chroot.h +++ b/hw/9pfs/virtio-9p-chroot.h @@ -37,5 +37,6 @@ typedef struct V9fsFileObjectRequest int v9fs_chroot(FsContext *fs_ctx); +int v9fs_request(FsContext *fs_ctx, V9fsFileObjectRequest *or, 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 0a015de..96e8181 100644 --- a/hw/9pfs/virtio-9p-local.c +++ b/hw/9pfs/virtio-9p-local.c @@ -13,6 +13,7 @@ #include "virtio.h" #include "virtio-9p.h" #include "virtio-9p-xattr.h" +#include "virtio-9p-chroot.h" #include <arpa/inet.h> #include <pwd.h> #include <grp.h> @@ -20,6 +21,36 @@ #include <sys/un.h> #include <attr/xattr.h> +/* Helper routine to fill V9fsFileObjectRequest structure */ +static void fill_request(V9fsFileObjectRequest *request, const char *path, + FsCred *credp) +{ + memset(request, 0, sizeof(*request)); + request->data.path_len = strlen(path); + request->path.path = qemu_strdup(path); + if (credp) { + request->data.mode = credp->fc_mode; + request->data.uid = credp->fc_uid; + request->data.gid = credp->fc_gid; + request->data.dev = credp->fc_rdev; + } +} + +static int passthrough_open(FsContext *fs_ctx, const char *path, int flags) +{ + V9fsFileObjectRequest request; + int fd, error = 0; + + fill_request(&request, path, NULL); + request.data.flags = flags; + request.data.type = T_OPEN; + fd = v9fs_request(fs_ctx, &request, &error); + if (fd < 0) { + errno = error; + } + qemu_free((void *)request.path.path); + return fd; +} static int local_lstat(FsContext *fs_ctx, const char *path, struct stat *stbuf) { @@ -138,14 +169,27 @@ static int local_closedir(FsContext *ctx, DIR *dir) return closedir(dir); } -static int local_open(FsContext *ctx, const char *path, int flags) +static int local_open(FsContext *fs_ctx, const char *path, int flags) { - return open(rpath(ctx, path), flags); + if (fs_ctx->fs_sm == SM_PASSTHROUGH) { + return passthrough_open(fs_ctx, path, flags); + } else { + return open(rpath(fs_ctx, path), flags); + } } -static DIR *local_opendir(FsContext *ctx, const char *path) +static DIR *local_opendir(FsContext *fs_ctx, const char *path) { - return opendir(rpath(ctx, path)); + if (fs_ctx->fs_sm == SM_PASSTHROUGH) { + int fd; + fd = passthrough_open(fs_ctx, path, O_DIRECTORY); + if (fd < 0) { + return NULL; + } + return fdopendir(fd); + } else { + return opendir(rpath(fs_ctx, path)); + } } static void local_rewinddir(FsContext *ctx, DIR *dir) -- 1.7.3.4