From patchwork Wed Mar 9 17:16:00 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mohan Kumar M X-Patchwork-Id: 86133 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [199.232.76.165]) by ozlabs.org (Postfix) with ESMTP id 7D4F0B6F82 for ; Thu, 10 Mar 2011 04:25:46 +1100 (EST) Received: from localhost ([127.0.0.1]:41451 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PxN36-0007jq-So for incoming@patchwork.ozlabs.org; Wed, 09 Mar 2011 12:19:48 -0500 Received: from [140.186.70.92] (port=58394 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PxMzk-00056t-RI for qemu-devel@nongnu.org; Wed, 09 Mar 2011 12:16:23 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PxMzh-0005NJ-EF for qemu-devel@nongnu.org; Wed, 09 Mar 2011 12:16:19 -0500 Received: from e28smtp01.in.ibm.com ([122.248.162.1]:57666) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PxMzg-0005MH-BI for qemu-devel@nongnu.org; Wed, 09 Mar 2011 12:16:17 -0500 Received: from d28relay01.in.ibm.com (d28relay01.in.ibm.com [9.184.220.58]) by e28smtp01.in.ibm.com (8.14.4/8.13.1) with ESMTP id p29HGAb1019052 for ; Wed, 9 Mar 2011 22:46:10 +0530 Received: from d28av01.in.ibm.com (d28av01.in.ibm.com [9.184.220.63]) by d28relay01.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p29HG83l3453122 for ; Wed, 9 Mar 2011 22:46:08 +0530 Received: from d28av01.in.ibm.com (loopback [127.0.0.1]) by d28av01.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p29HG80u020263 for ; Wed, 9 Mar 2011 22:46:09 +0530 Received: from explorer.in.ibm.com ([9.124.208.3]) by d28av01.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id p29HG4wG020116; Wed, 9 Mar 2011 22:46:08 +0530 From: "M. Mohan Kumar" To: qemu-devel@nongnu.org, Stefan Hajnoczi Date: Wed, 9 Mar 2011 22:46:00 +0530 Message-Id: <1299690960-12007-12-git-send-email-mohan@in.ibm.com> X-Mailer: git-send-email 1.7.3.4 In-Reply-To: <1299690960-12007-1-git-send-email-mohan@in.ibm.com> References: <1299690960-12007-1-git-send-email-mohan@in.ibm.com> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6, seldom 2.4 (older, 4) X-Received-From: 122.248.162.1 Cc: Subject: [Qemu-devel] [V8 PATCH 11/11] virtio-9p: Chroot environment for other functions X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Add chroot functionality for systemcalls that can operate on a file using relative directory file descriptor. Signed-off-by: M. Mohan Kumar --- hw/9pfs/virtio-9p-local.c | 156 ++++++++++++++++++++++++++++++++++++++++----- 1 files changed, 139 insertions(+), 17 deletions(-) diff --git a/hw/9pfs/virtio-9p-local.c b/hw/9pfs/virtio-9p-local.c index 1670e33..0157eb8 100644 --- a/hw/9pfs/virtio-9p-local.c +++ b/hw/9pfs/virtio-9p-local.c @@ -22,6 +22,7 @@ #include #include #include +#include /* Helper routine to fill V9fsFileObjectRequest structure */ static int fill_fileobjectrequest(V9fsFileObjectRequest *request, @@ -70,14 +71,41 @@ static int passthrough_request(FsContext *fs_ctx, const char *old_path, return retval; } +/* + * Returns file descriptor of dirname(path) + * This fd can be used by *at functions + */ +static int get_dirfd(FsContext *fs_ctx, const char *path) +{ + V9fsFileObjectRequest request; + int fd; + char *dpath = qemu_strdup(path); + + fd = fill_fileobjectrequest(&request, dirname(dpath), NULL); + if (fd < 0) { + qemu_free(dpath); + errno = -fd; + return -1; + } + request.data.type = T_OPEN; + fd = v9fs_request(fs_ctx, &request); + qemu_free(dpath); + if (fd < 0) { + errno = -fd; + fd = -1; + } + return fd; +} + static int local_lstat(FsContext *fs_ctx, const char *path, struct stat *stbuf) { int err; - err = lstat(rpath(fs_ctx, path), stbuf); - if (err) { - return err; - } + if (fs_ctx->fs_sm == SM_MAPPED) { + err = lstat(rpath(fs_ctx, path), stbuf); + if (err) { + return err; + } /* Actual credentials are part of extended attrs */ uid_t tmp_uid; gid_t tmp_gid; @@ -99,6 +127,27 @@ static int local_lstat(FsContext *fs_ctx, const char *path, struct stat *stbuf) sizeof(dev_t)) > 0) { stbuf->st_rdev = tmp_dev; } + } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) { + int pfd, serrno = 0; + char *tmp_path; + + pfd = get_dirfd(fs_ctx, path); + if (pfd < 0) { + return -1; + } + tmp_path = qemu_strdup(path); + err = fstatat(pfd, basename(tmp_path), stbuf, AT_SYMLINK_NOFOLLOW); + if (err < 0) { + serrno = errno; + } + close(pfd); + qemu_free(tmp_path); + errno = serrno; + } else { + err = lstat(rpath(fs_ctx, path), stbuf); + if (err) { + return err; + } } return err; } @@ -163,9 +212,23 @@ static ssize_t local_readlink(FsContext *fs_ctx, const char *path, } while (tsize == -1 && errno == EINTR); close(fd); return tsize; - } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) || - (fs_ctx->fs_sm == SM_NONE)) { + } else if (fs_ctx->fs_sm == SM_NONE) { tsize = readlink(rpath(fs_ctx, path), buf, bufsz); + } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) { + int pfd, serrno = 0; + char *tmp_path; + pfd = get_dirfd(fs_ctx, path); + if (pfd < 0) { + return -1; + } + tmp_path = qemu_strdup(path); + tsize = readlinkat(pfd, basename(tmp_path), buf, bufsz); + if (tsize < 0) { + serrno = errno; + } + close(pfd); + qemu_free(tmp_path); + errno = serrno; } return tsize; } @@ -257,8 +320,23 @@ static int local_chmod(FsContext *fs_ctx, const char *path, FsCred *credp) { if (fs_ctx->fs_sm == SM_MAPPED) { return local_set_xattr(rpath(fs_ctx, path), credp); - } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) || - (fs_ctx->fs_sm == SM_NONE)) { + } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) { + int pfd, err, serrno = 0; + char *tmp_path; + pfd = get_dirfd(fs_ctx, path); + if (pfd < 0) { + return -1; + } + tmp_path = qemu_strdup(path); + err = fchmodat(pfd, basename(tmp_path), credp->fc_mode, 0); + if (err == -1) { + serrno = errno; + } + qemu_free(tmp_path); + close(pfd); + errno = serrno; + return err; + } else if (fs_ctx->fs_sm == SM_NONE) { return chmod(rpath(fs_ctx, path), credp->fc_mode); } return -1; @@ -506,7 +584,21 @@ static int local_link(FsContext *fs_ctx, const char *oldpath, static int local_truncate(FsContext *ctx, const char *path, off_t size) { - return truncate(rpath(ctx, path), size); + if (ctx->fs_sm == SM_PASSTHROUGH) { + int fd, retval, serrno; + fd = passthrough_request(ctx, NULL, path, O_RDWR, NULL, T_OPEN); + if (fd < 0) { + errno = -fd; + return -1; + } + retval = ftruncate(fd, size); + serrno = errno; + close(fd); + errno = serrno; + return retval; + } else { + return truncate(rpath(ctx, path), size); + } } static int local_rename(FsContext *ctx, const char *oldpath, @@ -536,22 +628,52 @@ static int local_rename(FsContext *ctx, const char *oldpath, static int local_chown(FsContext *fs_ctx, const char *path, FsCred *credp) { - if ((credp->fc_uid == -1 && credp->fc_gid == -1) || - (fs_ctx->fs_sm == SM_PASSTHROUGH)) { + if (fs_ctx->fs_sm != SM_PASSTHROUGH && + (credp->fc_uid == -1 && credp->fc_gid == -1)) { + return lchown(rpath(fs_ctx, path), credp->fc_uid, credp->fc_gid); + } else if (fs_ctx->fs_sm == SM_NONE) { return lchown(rpath(fs_ctx, path), credp->fc_uid, credp->fc_gid); } else if (fs_ctx->fs_sm == SM_MAPPED) { return local_set_xattr(rpath(fs_ctx, path), credp); - } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) || - (fs_ctx->fs_sm == SM_NONE)) { - return lchown(rpath(fs_ctx, path), credp->fc_uid, credp->fc_gid); + } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) { + int pfd, err, serrno = 0; + char *old_path; + pfd = get_dirfd(fs_ctx, path); + if (pfd < 0) { + return -1; + } + old_path = qemu_strdup(path); + err = fchownat(pfd, basename(old_path), credp->fc_uid, credp->fc_gid, + AT_SYMLINK_NOFOLLOW); + if (err == -1) { + serrno = errno; + } + qemu_free(old_path); + close(pfd); + errno = serrno; + return err; } return -1; } -static int local_utimensat(FsContext *s, const char *path, - const struct timespec *buf) +static int local_utimensat(FsContext *fs_ctx, const char *path, + const struct timespec *buf) { - return qemu_utimensat(AT_FDCWD, rpath(s, path), buf, AT_SYMLINK_NOFOLLOW); + if (fs_ctx->fs_sm == SM_PASSTHROUGH) { + int fd, retval; + fd = passthrough_request(fs_ctx, NULL, path, + O_RDONLY | O_NONBLOCK | O_NOFOLLOW, NULL, T_OPEN); + if (fd < 0) { + errno = -fd; + return -1; + } + retval = futimens(fd, buf); + close(fd); + return retval; + } else { + return utimensat(AT_FDCWD, rpath(fs_ctx, path), buf, + AT_SYMLINK_NOFOLLOW); + } } static int local_remove(FsContext *ctx, const char *path)