[Qemu-devel] [PATCH v10 0/7] file descriptor passing using fd sets

[Qemu-devel] [PATCH v10 0/7] file descriptor passing using fd sets

[Corey Bryant]

libvirt's sVirt security driver provides SELinux MAC isolation for
Qemu guest processes and their corresponding image files.  In other
words, sVirt uses SELinux to prevent a QEMU process from opening
files that do not belong to it.

sVirt provides this support by labeling guests and resources with
security labels that are stored in file system extended attributes.
Some file systems, such as NFS, do not support the extended
attribute security namespace, and therefore cannot support sVirt
isolation.

A solution to this problem is to provide fd passing support, where
libvirt opens files and passes file descriptors to QEMU.  This,
along with SELinux policy to prevent QEMU from opening files, can
provide image file isolation for NFS files stored on the same NFS
mount.

This patch series adds the add-fd, remove-fd, and query-fdsets
QMP monitor commands, which allow file descriptors to be passed
via SCM_RIGHTS, and assigned to specified fd sets.  This allows
fd sets to be created per file with fds having, for example,
different access rights.  When QEMU needs to reopen a file with
different access rights, it can search for a matching fd in the
fd set.  Fd sets also allow for easy tracking of fds per file,
helping to prevent fd leaks.

Support is also added to the block layer to allow QEMU to dup an
fd from an fdset when the filename is of the /dev/fdset/nnn format,
where nnn is the fd set ID.

No new SELinux policy is required to prevent open of NFS files
(files with type nfs_t).  The virt_use_nfs boolean type simply
needs to be set to false, and open will be prevented (and dup will
be allowed).  For example:

    # setsebool virt_use_nfs 0
    # getsebool virt_use_nfs
    virt_use_nfs --> off

Corey Bryant (7):
  qemu-char: Add MSG_CMSG_CLOEXEC flag to recvmsg
  qapi: Introduce add-fd, remove-fd, query-fdsets
  block: Prevent detection of /dev/fdset/ as floppy
  block: Convert open calls to qemu_open
  block: Convert close calls to qemu_close
  block: Enable qemu_open/close to work with fd sets
  monitor: Clean up fd sets on monitor disconnect

 block/raw-posix.c |   46 +++++----
 block/raw-win32.c |    6 +-
 block/vdi.c       |    5 +-
 block/vmdk.c      |   25 ++---
 block/vpc.c       |    4 +-
 block/vvfat.c     |   16 +--
 cutils.c          |    5 +
 monitor.c         |  291 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 monitor.h         |    5 +
 osdep.c           |  114 +++++++++++++++++++++
 qapi-schema.json  |   98 ++++++++++++++++++
 qemu-char.c       |   12 ++-
 qemu-common.h     |    2 +
 qemu-tool.c       |   20 ++++
 qmp-commands.hx   |  122 ++++++++++++++++++++++
 savevm.c          |    4 +-
 16 files changed, 720 insertions(+), 55 deletions(-)

-- 
1.7.10.4

[Qemu-devel] [PATCH v10 1/7] qemu-char: Add MSG_CMSG_CLOEXEC flag to recvmsg

[Corey Bryant]

Set the close-on-exec flag for the file descriptor received
via SCM_RIGHTS.

Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com>
---
v4
 -This patch is new in v4 (eblake@redhat.com)

v5
 -Fallback to FD_CLOEXEC if MSG_CMSG_CLOEXEC is not available
  (eblake@redhat.com, stefanha@linux.vnet.ibm.com)

v6
 -Set cloexec on correct fd (eblake@redhat.com)

v7-v10
 -No changes

 qemu-char.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/qemu-char.c b/qemu-char.c
index c2aaaee..ab4a928 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -2238,6 +2238,9 @@ static void unix_process_msgfd(CharDriverState *chr, struct msghdr *msg)
         if (fd < 0)
             continue;
 
+#ifndef MSG_CMSG_CLOEXEC
+        qemu_set_cloexec(fd);
+#endif
         if (s->msgfd != -1)
             close(s->msgfd);
         s->msgfd = fd;
@@ -2253,6 +2256,7 @@ static ssize_t tcp_chr_recv(CharDriverState *chr, char *buf, size_t len)
         struct cmsghdr cmsg;
         char control[CMSG_SPACE(sizeof(int))];
     } msg_control;
+    int flags = 0;
     ssize_t ret;
 
     iov[0].iov_base = buf;
@@ -2263,9 +2267,13 @@ static ssize_t tcp_chr_recv(CharDriverState *chr, char *buf, size_t len)
     msg.msg_control = &msg_control;
     msg.msg_controllen = sizeof(msg_control);
 
-    ret = recvmsg(s->fd, &msg, 0);
-    if (ret > 0 && s->is_unix)
+#ifdef MSG_CMSG_CLOEXEC
+    flags |= MSG_CMSG_CLOEXEC;
+#endif
+    ret = recvmsg(s->fd, &msg, flags);
+    if (ret > 0 && s->is_unix) {
         unix_process_msgfd(chr, &msg);
+    }
 
     return ret;
 }
-- 
1.7.10.4

[Qemu-devel] [PATCH v10 2/7] qapi: Introduce add-fd, remove-fd, query-fdsets

[Corey Bryant]

This patch adds support that enables passing of file descriptors
to the QEMU monitor where they will be stored in specified file
descriptor sets.

A file descriptor set can be used by a client like libvirt to
store file descriptors for the same file.  This allows the
client to open a file with different access modes (O_RDWR,
O_WRONLY, O_RDONLY) and add/remove the passed fds to/from an fd
set as needed.  This will allow QEMU to (in a later patch in this
series) "open" and "reopen" the same file by dup()ing the fd in
the fd set that corresponds to the file, where the fd has the
matching access mode flag that QEMU requests.

The new QMP commands are:
  add-fd: Add a file descriptor to an fd set
  remove-fd: Remove a file descriptor from an fd set
  query-fdsets: Return information describing all fd sets

Note: These commands are not compatible with the existing getfd
and closefd QMP commands.

Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com>
---
v5:
 -This patch is new in v5 and replaces the pass-fd QMP command
  from v4.
 -By grouping fds in fd sets, we ease managability with an fd
  set per file, addressing concerns raised in v4 about handling
  "reopens" and preventing fd leakage. (eblake@redhat.com,
  kwolf@redhat.com, dberrange@redhat.com)

v6
 -Make @fd optional for remove-fd (eblake@redhat.com)
 -Make @fdset-id optional for add-fd (eblake@redhat.com)

v7:
 -Share fd sets among all monitor connections (kwolf@redhat.com)
 -Added mon_refcount to keep track of monitor connection count.

v8:
 -Add opaque string to add-fd/query-fdsets.
  (stefanha@linux.vnet.ibm.com)
 -Use camel case for structures. (stefanha@linux.vnet.ibm.com)
 -Don't return in-use and refcount from query-fdsets.
  (stefanha@linux.vnet.ibm.com)
 -Don't return removed fd's from query-fdsets.
  (stefanha@linux.vnet.ibm.com)
 -Use fdset-id rather than fdset_id. (eblake@redhat.com)
 -Fix fd leak in qmp_add_fd(). (stefanha@linux.vnet.ibm.com)
 -Update QMP errors. (stefanha@linux.vnet.ibm.com, eblake@redhat.com)

v9:
 -Use fdset-id rather than fdset_id. (eblake@redhat.com)
 -Update example for query-fdsets. (eblake@redhat.com)
 -Close fd immediately on remove-fd.
  (kwolf@redhat.com, eblake@redhat.com)
 -Drop fdset refcount, and check dup_fds instead (in a later patch).
  (eblake@redhat.com)
 -Move mon_refcount code to a later patch. (kwolf@redhat.com)

v10
 -No trailing comma in query-fdsets example. (eblake@redhat.com)
 -Two separate messages in qmp_remove_fd. (eblake@redhat.com)
 -Modify text in qmp_add_fd invalid parameter error message.
  (eblake@redhat.com)

 monitor.c        |  189 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 qapi-schema.json |   98 ++++++++++++++++++++++++++++
 qmp-commands.hx  |  122 +++++++++++++++++++++++++++++++++++
 3 files changed, 409 insertions(+)

diff --git a/monitor.c b/monitor.c
index 49dccfe..6252d39 100644
--- a/monitor.c
+++ b/monitor.c
@@ -140,6 +140,23 @@ struct mon_fd_t {
     QLIST_ENTRY(mon_fd_t) next;
 };
 
+/* file descriptor associated with a file descriptor set */
+typedef struct MonFdsetFd MonFdsetFd;
+struct MonFdsetFd {
+    int fd;
+    bool removed;
+    char *opaque;
+    QLIST_ENTRY(MonFdsetFd) next;
+};
+
+/* file descriptor set containing fds passed via SCM_RIGHTS */
+typedef struct MonFdset MonFdset;
+struct MonFdset {
+    int64_t id;
+    QLIST_HEAD(, MonFdsetFd) fds;
+    QLIST_ENTRY(MonFdset) next;
+};
+
 typedef struct MonitorControl {
     QObject *id;
     JSONMessageParser parser;
@@ -211,6 +228,7 @@ static inline int mon_print_count_get(const Monitor *mon) { return 0; }
 #define QMP_ACCEPT_UNKNOWNS 1
 
 static QLIST_HEAD(mon_list, Monitor) mon_list;
+static QLIST_HEAD(mon_fdsets, MonFdset) mon_fdsets;
 
 static mon_cmd_t mon_cmds[];
 static mon_cmd_t info_cmds[];
@@ -2389,6 +2407,177 @@ int monitor_get_fd(Monitor *mon, const char *fdname)
     return -1;
 }
 
+static void monitor_fdset_cleanup(MonFdset *mon_fdset)
+{
+    MonFdsetFd *mon_fdset_fd;
+    MonFdsetFd *mon_fdset_fd_next;
+
+    QLIST_FOREACH_SAFE(mon_fdset_fd, &mon_fdset->fds, next, mon_fdset_fd_next) {
+        if (mon_fdset_fd->removed) {
+            close(mon_fdset_fd->fd);
+            g_free(mon_fdset_fd->opaque);
+            QLIST_REMOVE(mon_fdset_fd, next);
+            g_free(mon_fdset_fd);
+        }
+    }
+
+    if (QLIST_EMPTY(&mon_fdset->fds)) {
+        QLIST_REMOVE(mon_fdset, next);
+        g_free(mon_fdset);
+    }
+}
+
+AddfdInfo *qmp_add_fd(bool has_fdset_id, int64_t fdset_id, bool has_opaque,
+                      const char *opaque, Error **errp)
+{
+    int fd;
+    Monitor *mon = cur_mon;
+    MonFdset *mon_fdset;
+    MonFdsetFd *mon_fdset_fd;
+    AddfdInfo *fdinfo;
+
+    fd = qemu_chr_fe_get_msgfd(mon->chr);
+    if (fd == -1) {
+        error_set(errp, QERR_FD_NOT_SUPPLIED);
+        goto error;
+    }
+
+    if (has_fdset_id) {
+        QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
+            if (mon_fdset->id == fdset_id) {
+                break;
+            }
+        }
+        if (mon_fdset == NULL) {
+            error_set(errp, QERR_INVALID_PARAMETER_VALUE, "fdset-id",
+                      "an existing fdset-id");
+            goto error;
+        }
+    } else {
+        int64_t fdset_id_prev = -1;
+        MonFdset *mon_fdset_cur = QLIST_FIRST(&mon_fdsets);
+
+        /* Use first available fdset ID */
+        QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
+            mon_fdset_cur = mon_fdset;
+            if (fdset_id_prev == mon_fdset_cur->id - 1) {
+                fdset_id_prev = mon_fdset_cur->id;
+                continue;
+            }
+            break;
+        }
+
+        mon_fdset = g_malloc0(sizeof(*mon_fdset));
+        mon_fdset->id = fdset_id_prev + 1;
+
+        /* The fdset list is ordered by fdset ID */
+        if (mon_fdset->id == 0) {
+            QLIST_INSERT_HEAD(&mon_fdsets, mon_fdset, next);
+        } else if (mon_fdset->id < mon_fdset_cur->id) {
+            QLIST_INSERT_BEFORE(mon_fdset_cur, mon_fdset, next);
+        } else {
+            QLIST_INSERT_AFTER(mon_fdset_cur, mon_fdset, next);
+        }
+    }
+
+    mon_fdset_fd = g_malloc0(sizeof(*mon_fdset_fd));
+    mon_fdset_fd->fd = fd;
+    mon_fdset_fd->removed = false;
+    if (has_opaque) {
+        mon_fdset_fd->opaque = g_strdup(opaque);
+    }
+    QLIST_INSERT_HEAD(&mon_fdset->fds, mon_fdset_fd, next);
+
+    fdinfo = g_malloc0(sizeof(*fdinfo));
+    fdinfo->fdset_id = mon_fdset->id;
+    fdinfo->fd = mon_fdset_fd->fd;
+
+    return fdinfo;
+
+error:
+    if (fd != -1) {
+        close(fd);
+    }
+    return NULL;
+}
+
+void qmp_remove_fd(int64_t fdset_id, bool has_fd, int64_t fd, Error **errp)
+{
+    MonFdset *mon_fdset;
+    MonFdsetFd *mon_fdset_fd;
+    char fd_str[60];
+
+    QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
+        if (mon_fdset->id != fdset_id) {
+            continue;
+        }
+        QLIST_FOREACH(mon_fdset_fd, &mon_fdset->fds, next) {
+            if (has_fd) {
+                if (mon_fdset_fd->fd != fd) {
+                    continue;
+                }
+                mon_fdset_fd->removed = true;
+                break;
+            } else {
+                mon_fdset_fd->removed = true;
+            }
+        }
+        if (has_fd && !mon_fdset_fd) {
+            goto error;
+        }
+        monitor_fdset_cleanup(mon_fdset);
+        return;
+    }
+
+error:
+    if (has_fd) {
+        snprintf(fd_str, sizeof(fd_str), "fdset-id:%" PRId64 ", fd:%" PRId64,
+                 fdset_id, fd);
+    } else {
+        snprintf(fd_str, sizeof(fd_str), "fdset-id:%" PRId64, fdset_id);
+    }
+    error_set(errp, QERR_FD_NOT_FOUND, fd_str);
+}
+
+FdsetInfoList *qmp_query_fdsets(Error **errp)
+{
+    MonFdset *mon_fdset;
+    MonFdsetFd *mon_fdset_fd;
+    FdsetInfoList *fdset_list = NULL;
+
+    QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
+        FdsetInfoList *fdset_info = g_malloc0(sizeof(*fdset_info));
+        FdsetFdInfoList *fdsetfd_list = NULL;
+
+        fdset_info->value = g_malloc0(sizeof(*fdset_info->value));
+        fdset_info->value->fdset_id = mon_fdset->id;
+
+        QLIST_FOREACH(mon_fdset_fd, &mon_fdset->fds, next) {
+            FdsetFdInfoList *fdsetfd_info;
+
+            fdsetfd_info = g_malloc0(sizeof(*fdsetfd_info));
+            fdsetfd_info->value = g_malloc0(sizeof(*fdsetfd_info->value));
+            fdsetfd_info->value->fd = mon_fdset_fd->fd;
+            if (mon_fdset_fd->opaque) {
+                fdsetfd_info->value->has_opaque = true;
+                fdsetfd_info->value->opaque = g_strdup(mon_fdset_fd->opaque);
+            } else {
+                fdsetfd_info->value->has_opaque = false;
+            }
+
+            fdsetfd_info->next = fdsetfd_list;
+            fdsetfd_list = fdsetfd_info;
+        }
+
+        fdset_info->value->fds = fdsetfd_list;
+
+        fdset_info->next = fdset_list;
+        fdset_list = fdset_info;
+    }
+
+    return fdset_list;
+}
+
 /* mon_cmds and info_cmds would be sorted at runtime */
 static mon_cmd_t mon_cmds[] = {
 #include "hmp-commands.h"
diff --git a/qapi-schema.json b/qapi-schema.json
index bd9c450..53cf083 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -2199,3 +2199,101 @@
 # Since: 0.14.0
 ##
 { 'command': 'closefd', 'data': {'fdname': 'str'} }
+
+# @AddfdInfo:
+#
+# Information about a file descriptor that was added to an fd set.
+#
+# @fdset-id: The ID of the fd set that @fd was added to.
+#
+# @fd: The file descriptor that was received via SCM rights and
+#      added to the fd set.
+#
+# Since: 1.2.0
+##
+{ 'type': 'AddfdInfo', 'data': {'fdset-id': 'int', 'fd': 'int'} }
+
+##
+# @add-fd:
+#
+# Add a file descriptor, that was passed via SCM rights, to an fd set.
+#
+# @fdset-id: #optional The ID of the fd set to add the file descriptor to.
+#
+# @opaque: #optional A free-form string that can be used to describe the fd.
+#
+# Returns: @AddfdInfo on success
+#          If file descriptor was not received, FdNotSupplied
+#          If @fdset-id does not exist, InvalidParameterValue
+#
+# Notes: The list of fd sets is shared by all monitor connections.
+#
+#        If @fdset-id is not specified, a new fd set will be created.
+#
+# Since: 1.2.0
+##
+{ 'command': 'add-fd', 'data': {'*fdset-id': 'int', '*opaque': 'str'},
+  'returns': 'AddfdInfo' }
+
+##
+# @remove-fd:
+#
+# Remove a file descriptor from an fd set.
+#
+# @fdset-id: The ID of the fd set that the file descriptor belongs to.
+#
+# @fd: #optional The file descriptor that is to be removed.
+#
+# Returns: Nothing on success
+#          If @fdset-id or @fd is not found, FdNotFound
+#
+# Since: 1.2.0
+#
+# Notes: The list of fd sets is shared by all monitor connections.
+#
+#        If @fd is not specified, all file descriptors in @fdset-id
+#        will be removed.
+##
+{ 'command': 'remove-fd', 'data': {'fdset-id': 'int', '*fd': 'int'} }
+
+##
+# @FdsetFdInfo:
+#
+# Information about a file descriptor that belongs to an fd set.
+#
+# @fd: The file descriptor value.
+#
+# @opaque: #optional A free-form string that can be used to describe the fd.
+#
+# Since: 1.2.0
+##
+{ 'type': 'FdsetFdInfo',
+  'data': {'fd': 'int', '*opaque': 'str'} }
+
+##
+# @FdsetInfo:
+#
+# Information about an fd set.
+#
+# @fdset-id: The ID of the fd set.
+#
+# @fds: A list of file descriptors that belong to this fd set.
+#
+# Since: 1.2.0
+##
+{ 'type': 'FdsetInfo',
+  'data': {'fdset-id': 'int', 'fds': ['FdsetFdInfo']} }
+
+##
+# @query-fdsets:
+#
+# Return information describing all fd sets.
+#
+# Returns: A list of @FdsetInfo
+#
+# Since: 1.2.0
+#
+# Note: The list of fd sets is shared by all monitor connections.
+#
+##
+{ 'command': 'query-fdsets', 'returns': ['FdsetInfo'] }
diff --git a/qmp-commands.hx b/qmp-commands.hx
index ac46638..89d53bc 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -926,6 +926,128 @@ Example:
 
 EQMP
 
+     {
+        .name       = "add-fd",
+        .args_type  = "fdset-id:i?,opaque:s?",
+        .params     = "add-fd fdset-id opaque",
+        .help       = "Add a file descriptor, that was passed via SCM rights, to an fd set",
+        .mhandler.cmd_new = qmp_marshal_input_add_fd,
+    },
+
+SQMP
+add-fd
+-------
+
+Add a file descriptor, that was passed via SCM rights, to an fd set.
+
+Arguments:
+
+- "fdset-id": The ID of the fd set to add the file descriptor to.
+              (json-int, optional)
+- "opaque": A free-form string that can be used to describe the fd.
+            (json-string, optional)
+
+Return a json-object with the following information:
+
+- "fdset-id": The ID of the fd set that the fd was added to. (json-int)
+- "fd": The file descriptor that was received via SCM rights and added to the
+        fd set. (json-int)
+
+Example:
+
+-> { "execute": "add-fd", "arguments": { "fdset-id": 1 } }
+<- { "return": { "fdset-id": 1, "fd": 3 } }
+
+Notes:
+
+(1) The list of fd sets is shared by all monitor connections.
+(2) If "fdset-id" is not specified, a new fd set will be created.
+
+EQMP
+
+     {
+        .name       = "remove-fd",
+        .args_type  = "fdset-id:i,fd:i?",
+        .params     = "remove-fd fdset-id fd",
+        .help       = "Remove a file descriptor from an fd set",
+        .mhandler.cmd_new = qmp_marshal_input_remove_fd,
+    },
+
+SQMP
+remove-fd
+---------
+
+Remove a file descriptor from an fd set.
+
+Arguments:
+
+- "fdset-id": The ID of the fd set that the file descriptor belongs to.
+              (json-int)
+- "fd": The file descriptor that is to be removed. (json-int, optional)
+
+Example:
+
+-> { "execute": "remove-fd", "arguments": { "fdset-id": 1, "fd": 3 } }
+<- { "return": {} }
+
+Notes:
+
+(1) The list of fd sets is shared by all monitor connections.
+(2) If "fd" is not specified, all file descriptors in "fdset-id" will be
+    removed.
+
+EQMP
+
+    {
+        .name       = "query-fdsets",
+        .args_type  = "",
+        .help       = "Return information describing all fd sets",
+        .mhandler.cmd_new = qmp_marshal_input_query_fdsets,
+    },
+
+SQMP
+query-fdsets
+-------------
+
+Return information describing all fd sets.
+
+Arguments: None
+
+Example:
+
+-> { "execute": "query-fdsets" }
+<- { "return": [
+       {
+         "fds": [
+           {
+             "fd": 30,
+             "opaque": "rdonly:/path/to/file"
+           },
+           {
+             "fd": 24,
+             "opaque": "rdwr:/path/to/file"
+           }
+         ],
+         "fdset-id": 1
+       },
+       {
+         "fds": [
+           {
+             "fd": 28
+           },
+           {
+             "fd": 29
+           }
+         ],
+         "fdset-id": 0
+       }
+     ]
+   }
+
+Note: The list of fd sets is shared by all monitor connections.
+
+EQMP
+
     {
         .name       = "block_passwd",
         .args_type  = "device:B,password:s",
-- 
1.7.10.4

[Qemu-devel] [PATCH v10 3/7] block: Prevent detection of /dev/fdset/ as floppy

[Corey Bryant]

Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com>
---
v8
 -This patch is new in v8. It was reported on a prior fd passing
  approach and I realized it's needed in this series.
  (kwolf@redhat.com)

v9-v10
 -No changes

 block/raw-posix.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/block/raw-posix.c b/block/raw-posix.c
index 0dce089..f606211 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -1052,8 +1052,10 @@ static int floppy_probe_device(const char *filename)
     struct floppy_struct fdparam;
     struct stat st;
 
-    if (strstart(filename, "/dev/fd", NULL))
+    if (strstart(filename, "/dev/fd", NULL) &&
+        !strstart(filename, "/dev/fdset/", NULL)) {
         prio = 50;
+    }
 
     fd = open(filename, O_RDONLY | O_NONBLOCK);
     if (fd < 0) {
-- 
1.7.10.4

[Qemu-devel] [PATCH v10 4/7] block: Convert open calls to qemu_open

[Corey Bryant]

This patch converts all block layer open calls to qemu_open.

Note that this adds the O_CLOEXEC flag to the changed open paths
when the O_CLOEXEC macro is defined.

Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com>
---
v2:
 -Convert calls to qemu_open instead of file_open (kwolf@redhat.com)
 -Mention introduction of O_CLOEXEC (kwolf@redhat.com)

v3-v10:
 -No changes

 block/raw-posix.c |   18 +++++++++---------
 block/raw-win32.c |    4 ++--
 block/vdi.c       |    5 +++--
 block/vmdk.c      |   21 +++++++++------------
 block/vpc.c       |    2 +-
 block/vvfat.c     |    4 ++--
 6 files changed, 26 insertions(+), 28 deletions(-)

diff --git a/block/raw-posix.c b/block/raw-posix.c
index f606211..08b997e 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -572,8 +572,8 @@ static int raw_create(const char *filename, QEMUOptionParameter *options)
         options++;
     }
 
-    fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
-              0644);
+    fd = qemu_open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
+                   0644);
     if (fd < 0) {
         result = -errno;
     } else {
@@ -846,7 +846,7 @@ static int hdev_open(BlockDriverState *bs, const char *filename, int flags)
         if ( bsdPath[ 0 ] != '\0' ) {
             strcat(bsdPath,"s0");
             /* some CDs don't have a partition 0 */
-            fd = open(bsdPath, O_RDONLY | O_BINARY | O_LARGEFILE);
+            fd = qemu_open(bsdPath, O_RDONLY | O_BINARY | O_LARGEFILE);
             if (fd < 0) {
                 bsdPath[strlen(bsdPath)-1] = '1';
             } else {
@@ -903,7 +903,7 @@ static int fd_open(BlockDriverState *bs)
 #endif
             return -EIO;
         }
-        s->fd = open(bs->filename, s->open_flags & ~O_NONBLOCK);
+        s->fd = qemu_open(bs->filename, s->open_flags & ~O_NONBLOCK);
         if (s->fd < 0) {
             s->fd_error_time = get_clock();
             s->fd_got_error = 1;
@@ -977,7 +977,7 @@ static int hdev_create(const char *filename, QEMUOptionParameter *options)
         options++;
     }
 
-    fd = open(filename, O_WRONLY | O_BINARY);
+    fd = qemu_open(filename, O_WRONLY | O_BINARY);
     if (fd < 0)
         return -errno;
 
@@ -1057,7 +1057,7 @@ static int floppy_probe_device(const char *filename)
         prio = 50;
     }
 
-    fd = open(filename, O_RDONLY | O_NONBLOCK);
+    fd = qemu_open(filename, O_RDONLY | O_NONBLOCK);
     if (fd < 0) {
         goto out;
     }
@@ -1110,7 +1110,7 @@ static void floppy_eject(BlockDriverState *bs, bool eject_flag)
         close(s->fd);
         s->fd = -1;
     }
-    fd = open(bs->filename, s->open_flags | O_NONBLOCK);
+    fd = qemu_open(bs->filename, s->open_flags | O_NONBLOCK);
     if (fd >= 0) {
         if (ioctl(fd, FDEJECT, 0) < 0)
             perror("FDEJECT");
@@ -1160,7 +1160,7 @@ static int cdrom_probe_device(const char *filename)
     int prio = 0;
     struct stat st;
 
-    fd = open(filename, O_RDONLY | O_NONBLOCK);
+    fd = qemu_open(filename, O_RDONLY | O_NONBLOCK);
     if (fd < 0) {
         goto out;
     }
@@ -1284,7 +1284,7 @@ static int cdrom_reopen(BlockDriverState *bs)
      */
     if (s->fd >= 0)
         close(s->fd);
-    fd = open(bs->filename, s->open_flags, 0644);
+    fd = qemu_open(bs->filename, s->open_flags, 0644);
     if (fd < 0) {
         s->fd = -1;
         return -EIO;
diff --git a/block/raw-win32.c b/block/raw-win32.c
index e4b0b75..8d7838d 100644
--- a/block/raw-win32.c
+++ b/block/raw-win32.c
@@ -255,8 +255,8 @@ static int raw_create(const char *filename, QEMUOptionParameter *options)
         options++;
     }
 
-    fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
-              0644);
+    fd = qemu_open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
+                   0644);
     if (fd < 0)
         return -EIO;
     set_sparse(fd);
diff --git a/block/vdi.c b/block/vdi.c
index 57325d6..c4f1529 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -653,8 +653,9 @@ static int vdi_create(const char *filename, QEMUOptionParameter *options)
         options++;
     }
 
-    fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY | O_LARGEFILE,
-              0644);
+    fd = qemu_open(filename,
+                   O_WRONLY | O_CREAT | O_TRUNC | O_BINARY | O_LARGEFILE,
+                   0644);
     if (fd < 0) {
         return -errno;
     }
diff --git a/block/vmdk.c b/block/vmdk.c
index 18e9b4c..557dc1b 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -1161,10 +1161,9 @@ static int vmdk_create_extent(const char *filename, int64_t filesize,
     VMDK4Header header;
     uint32_t tmp, magic, grains, gd_size, gt_size, gt_count;
 
-    fd = open(
-        filename,
-        O_WRONLY | O_CREAT | O_TRUNC | O_BINARY | O_LARGEFILE,
-        0644);
+    fd = qemu_open(filename,
+                   O_WRONLY | O_CREAT | O_TRUNC | O_BINARY | O_LARGEFILE,
+                   0644);
     if (fd < 0) {
         return -errno;
     }
@@ -1484,15 +1483,13 @@ static int vmdk_create(const char *filename, QEMUOptionParameter *options)
             (flags & BLOCK_FLAG_COMPAT6 ? 6 : 4),
             total_size / (int64_t)(63 * 16 * 512));
     if (split || flat) {
-        fd = open(
-                filename,
-                O_WRONLY | O_CREAT | O_TRUNC | O_BINARY | O_LARGEFILE,
-                0644);
+        fd = qemu_open(filename,
+                       O_WRONLY | O_CREAT | O_TRUNC | O_BINARY | O_LARGEFILE,
+                       0644);
     } else {
-        fd = open(
-                filename,
-                O_WRONLY | O_BINARY | O_LARGEFILE,
-                0644);
+        fd = qemu_open(filename,
+                       O_WRONLY | O_BINARY | O_LARGEFILE,
+                       0644);
     }
     if (fd < 0) {
         return -errno;
diff --git a/block/vpc.c b/block/vpc.c
index 5cd13d1..60ebf5a 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -678,7 +678,7 @@ static int vpc_create(const char *filename, QEMUOptionParameter *options)
     }
 
     /* Create the file */
-    fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
+    fd = qemu_open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
     if (fd < 0) {
         return -EIO;
     }
diff --git a/block/vvfat.c b/block/vvfat.c
index 7b1dcee..22b586a 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -1162,7 +1162,7 @@ static int open_file(BDRVVVFATState* s,mapping_t* mapping)
     if(!s->current_mapping ||
 	    strcmp(s->current_mapping->path,mapping->path)) {
 	/* open file */
-	int fd = open(mapping->path, O_RDONLY | O_BINARY | O_LARGEFILE);
+	int fd = qemu_open(mapping->path, O_RDONLY | O_BINARY | O_LARGEFILE);
 	if(fd<0)
 	    return -1;
 	vvfat_close_current_file(s);
@@ -2221,7 +2221,7 @@ static int commit_one_file(BDRVVVFATState* s,
     for (i = s->cluster_size; i < offset; i += s->cluster_size)
 	c = modified_fat_get(s, c);
 
-    fd = open(mapping->path, O_RDWR | O_CREAT | O_BINARY, 0666);
+    fd = qemu_open(mapping->path, O_RDWR | O_CREAT | O_BINARY, 0666);
     if (fd < 0) {
 	fprintf(stderr, "Could not open %s... (%s, %d)\n", mapping->path,
 		strerror(errno), errno);
-- 
1.7.10.4

[Qemu-devel] [PATCH v10 5/7] block: Convert close calls to qemu_close

[Corey Bryant]

This patch converts all block layer close calls, that correspond
to qemu_open calls, to qemu_close.

Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com>
---
v5:
 -This patch is new in v5. (kwolf@redhat.com, eblake@redhat.com)

v6-v9:
 -No changes

v10:
 -Don't use underscore prefix on functions. (blauwirbel@gmail.com)

 block/raw-posix.c |   24 ++++++++++++------------
 block/raw-win32.c |    2 +-
 block/vmdk.c      |    4 ++--
 block/vpc.c       |    2 +-
 block/vvfat.c     |   12 ++++++------
 osdep.c           |    5 +++++
 qemu-common.h     |    1 +
 savevm.c          |    4 ++--
 8 files changed, 30 insertions(+), 24 deletions(-)

diff --git a/block/raw-posix.c b/block/raw-posix.c
index 08b997e..6be20b1 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -271,7 +271,7 @@ static int raw_open_common(BlockDriverState *bs, const char *filename,
 out_free_buf:
     qemu_vfree(s->aligned_buf);
 out_close:
-    close(fd);
+    qemu_close(fd);
     return -errno;
 }
 
@@ -376,7 +376,7 @@ static void raw_close(BlockDriverState *bs)
 {
     BDRVRawState *s = bs->opaque;
     if (s->fd >= 0) {
-        close(s->fd);
+        qemu_close(s->fd);
         s->fd = -1;
         if (s->aligned_buf != NULL)
             qemu_vfree(s->aligned_buf);
@@ -580,7 +580,7 @@ static int raw_create(const char *filename, QEMUOptionParameter *options)
         if (ftruncate(fd, total_size * BDRV_SECTOR_SIZE) != 0) {
             result = -errno;
         }
-        if (close(fd) != 0) {
+        if (qemu_close(fd) != 0) {
             result = -errno;
         }
     }
@@ -850,7 +850,7 @@ static int hdev_open(BlockDriverState *bs, const char *filename, int flags)
             if (fd < 0) {
                 bsdPath[strlen(bsdPath)-1] = '1';
             } else {
-                close(fd);
+                qemu_close(fd);
             }
             filename = bsdPath;
         }
@@ -889,7 +889,7 @@ static int fd_open(BlockDriverState *bs)
     last_media_present = (s->fd >= 0);
     if (s->fd >= 0 &&
         (get_clock() - s->fd_open_time) >= FD_OPEN_TIMEOUT) {
-        close(s->fd);
+        qemu_close(s->fd);
         s->fd = -1;
 #ifdef DEBUG_FLOPPY
         printf("Floppy closed\n");
@@ -988,7 +988,7 @@ static int hdev_create(const char *filename, QEMUOptionParameter *options)
     else if (lseek(fd, 0, SEEK_END) < total_size * BDRV_SECTOR_SIZE)
         ret = -ENOSPC;
 
-    close(fd);
+    qemu_close(fd);
     return ret;
 }
 
@@ -1038,7 +1038,7 @@ static int floppy_open(BlockDriverState *bs, const char *filename, int flags)
         return ret;
 
     /* close fd so that we can reopen it as needed */
-    close(s->fd);
+    qemu_close(s->fd);
     s->fd = -1;
     s->fd_media_changed = 1;
 
@@ -1072,7 +1072,7 @@ static int floppy_probe_device(const char *filename)
         prio = 100;
 
 outc:
-    close(fd);
+    qemu_close(fd);
 out:
     return prio;
 }
@@ -1107,14 +1107,14 @@ static void floppy_eject(BlockDriverState *bs, bool eject_flag)
     int fd;
 
     if (s->fd >= 0) {
-        close(s->fd);
+        qemu_close(s->fd);
         s->fd = -1;
     }
     fd = qemu_open(bs->filename, s->open_flags | O_NONBLOCK);
     if (fd >= 0) {
         if (ioctl(fd, FDEJECT, 0) < 0)
             perror("FDEJECT");
-        close(fd);
+        qemu_close(fd);
     }
 }
 
@@ -1175,7 +1175,7 @@ static int cdrom_probe_device(const char *filename)
         prio = 100;
 
 outc:
-    close(fd);
+    qemu_close(fd);
 out:
     return prio;
 }
@@ -1283,7 +1283,7 @@ static int cdrom_reopen(BlockDriverState *bs)
      * FreeBSD seems to not notice sometimes...
      */
     if (s->fd >= 0)
-        close(s->fd);
+        qemu_close(s->fd);
     fd = qemu_open(bs->filename, s->open_flags, 0644);
     if (fd < 0) {
         s->fd = -1;
diff --git a/block/raw-win32.c b/block/raw-win32.c
index 8d7838d..c56bf83 100644
--- a/block/raw-win32.c
+++ b/block/raw-win32.c
@@ -261,7 +261,7 @@ static int raw_create(const char *filename, QEMUOptionParameter *options)
         return -EIO;
     set_sparse(fd);
     ftruncate(fd, total_size * 512);
-    close(fd);
+    qemu_close(fd);
     return 0;
 }
 
diff --git a/block/vmdk.c b/block/vmdk.c
index 557dc1b..daee426 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -1258,7 +1258,7 @@ static int vmdk_create_extent(const char *filename, int64_t filesize,
 
     ret = 0;
  exit:
-    close(fd);
+    qemu_close(fd);
     return ret;
 }
 
@@ -1506,7 +1506,7 @@ static int vmdk_create(const char *filename, QEMUOptionParameter *options)
     }
     ret = 0;
 exit:
-    close(fd);
+    qemu_close(fd);
     return ret;
 }
 
diff --git a/block/vpc.c b/block/vpc.c
index 60ebf5a..c0b82c4 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -744,7 +744,7 @@ static int vpc_create(const char *filename, QEMUOptionParameter *options)
     }
 
  fail:
-    close(fd);
+    qemu_close(fd);
     return ret;
 }
 
diff --git a/block/vvfat.c b/block/vvfat.c
index 22b586a..59d3c5b 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -1105,7 +1105,7 @@ static inline void vvfat_close_current_file(BDRVVVFATState *s)
     if(s->current_mapping) {
 	s->current_mapping = NULL;
 	if (s->current_fd) {
-		close(s->current_fd);
+		qemu_close(s->current_fd);
 		s->current_fd = 0;
 	}
     }
@@ -2230,7 +2230,7 @@ static int commit_one_file(BDRVVVFATState* s,
     }
     if (offset > 0) {
         if (lseek(fd, offset, SEEK_SET) != offset) {
-            close(fd);
+            qemu_close(fd);
             g_free(cluster);
             return -3;
         }
@@ -2251,13 +2251,13 @@ static int commit_one_file(BDRVVVFATState* s,
 	    (uint8_t*)cluster, (rest_size + 0x1ff) / 0x200);
 
         if (ret < 0) {
-            close(fd);
+            qemu_close(fd);
             g_free(cluster);
             return ret;
         }
 
         if (write(fd, cluster, rest_size) < 0) {
-            close(fd);
+            qemu_close(fd);
             g_free(cluster);
             return -2;
         }
@@ -2268,11 +2268,11 @@ static int commit_one_file(BDRVVVFATState* s,
 
     if (ftruncate(fd, size)) {
         perror("ftruncate()");
-        close(fd);
+        qemu_close(fd);
         g_free(cluster);
         return -4;
     }
-    close(fd);
+    qemu_close(fd);
     g_free(cluster);
 
     return commit_mappings(s, first_cluster, dir_index);
diff --git a/osdep.c b/osdep.c
index c07faf5..7f876ae 100644
--- a/osdep.c
+++ b/osdep.c
@@ -107,6 +107,11 @@ int qemu_open(const char *name, int flags, ...)
     return ret;
 }
 
+int qemu_close(int fd)
+{
+    return close(fd);
+}
+
 /*
  * A variant of write(2) which handles partial write.
  *
diff --git a/qemu-common.h b/qemu-common.h
index f9deca6..90ddacd 100644
--- a/qemu-common.h
+++ b/qemu-common.h
@@ -207,6 +207,7 @@ const char *path(const char *pathname);
 void *qemu_oom_check(void *ptr);
 
 int qemu_open(const char *name, int flags, ...);
+int qemu_close(int fd);
 ssize_t qemu_write_full(int fd, const void *buf, size_t count)
     QEMU_WARN_UNUSED_RESULT;
 ssize_t qemu_send_full(int fd, const void *buf, size_t count, int flags)
diff --git a/savevm.c b/savevm.c
index 6e82b2d..1e69c37 100644
--- a/savevm.c
+++ b/savevm.c
@@ -513,7 +513,7 @@ static void qemu_fill_buffer(QEMUFile *f)
  *
  * Returns f->close() return value, or 0 if close function is not set.
  */
-static int qemu_close(QEMUFile *f)
+static int qemu_fclose_internal(QEMUFile *f)
 {
     int ret = 0;
     if (f->close) {
@@ -535,7 +535,7 @@ int qemu_fclose(QEMUFile *f)
 {
     int ret;
     qemu_fflush(f);
-    ret = qemu_close(f);
+    ret = qemu_fclose_internal(f);
     /* If any error was spotted before closing, we should report it
      * instead of the close() return value.
      */
-- 
1.7.10.4

[Qemu-devel] [PATCH v10 6/7] block: Enable qemu_open/close to work with fd sets

[Corey Bryant]

When qemu_open is passed a filename of the "/dev/fdset/nnn"
format (where nnn is the fdset ID), an fd with matching access
mode flags will be searched for within the specified monitor
fd set.  If the fd is found, a dup of the fd will be returned
from qemu_open.

Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com>
---
v2:
 -Get rid of file_open and move dup code to qemu_open
  (kwolf@redhat.com)
 -Use strtol wrapper instead of atoi (kwolf@redhat.com)

v3:
 -Add note about fd leakage (eblake@redhat.com)

v4
 -Moved patch to be later in series (lcapitulino@redhat.com)
 -Update qemu_open to check access mode flags and set flags that
  can be set (eblake@redhat.com, kwolf@redhat.com)

v5:
 -This patch was overhauled quite a bit in this version, with
  the addition of fd set and refcount support.
 -Use qemu_set_cloexec() on dup'd fd (eblake@redhat.com)
 -Modify flags set by fcntl on dup'd fd (eblake@redhat.com)
 -Reduce syscalls when setting flags for dup'd fd (eblake@redhat.com)
 -Fix O_RDWR, O_RDONLY, O_WRONLY checks (eblake@redhat.com)

v6:
 -Pass only the fd to qemu_close() and keep track of dup fds per fd
  set. (kwolf@redhat.com, eblake@redhat.com)
 -Handle refcount incr/decr in new dup_fd_add/remove fd functions.
 -Use qemu_set_cloexec() appropriately in qemu_dup() (kwolf@redhat.com)
 -Simplify setting of setfl_flags in qemu_dup() (kwolf@redhat.com)
 -Add preprocessor checks for F_DUPFD_CLOEXEC (eblake@redhat.com)
 -Simplify flag checking in monitor_fdset_get_fd() (kwolf@redhat.com)

v7:
 -Minor updates to reference global mon_fdsets, and to remove
  default_mon usage in osdep.c. (kwolf@redhat.com)

v8:
 -Use camel case for structures. (stefanha@linux.vnet.ibm.com)

v9:
 -Drop fdset refcount and check dup_fds instead. (eblake@redhat.com)
 -Fix dupfd leak in qemu_dup(). (eblake@redhat.com)
 -Always set O_CLOEXEC in qemu_dup(). (kwolf@redhat.com)
 -Change name of qemu_dup() to qemu_dup_flags(). (kwolf@redhat.com)

v10:
 -Don't use underscore prefix on functions. (blauwirbel@gmail.com)
 -Set errno if monitor_fdset_dup_fd_add() fails. (eblake@redhat.com)
 -Check dupfd for -1 on qemu_dup_flags() call. (eblake@redhat.com)

 cutils.c      |    5 +++
 monitor.c     |   83 ++++++++++++++++++++++++++++++++++++++++++-
 monitor.h     |    5 +++
 osdep.c       |  109 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 qemu-common.h |    1 +
 qemu-tool.c   |   20 +++++++++++
 6 files changed, 222 insertions(+), 1 deletion(-)

diff --git a/cutils.c b/cutils.c
index 9d4c570..8b0d2bb 100644
--- a/cutils.c
+++ b/cutils.c
@@ -382,3 +382,8 @@ int qemu_parse_fd(const char *param)
     }
     return fd;
 }
+
+int qemu_parse_fdset(const char *param)
+{
+    return qemu_parse_fd(param);
+}
diff --git a/monitor.c b/monitor.c
index 6252d39..f56d6a1 100644
--- a/monitor.c
+++ b/monitor.c
@@ -154,6 +154,7 @@ typedef struct MonFdset MonFdset;
 struct MonFdset {
     int64_t id;
     QLIST_HEAD(, MonFdsetFd) fds;
+    QLIST_HEAD(, MonFdsetFd) dup_fds;
     QLIST_ENTRY(MonFdset) next;
 };
 
@@ -2421,7 +2422,7 @@ static void monitor_fdset_cleanup(MonFdset *mon_fdset)
         }
     }
 
-    if (QLIST_EMPTY(&mon_fdset->fds)) {
+    if (QLIST_EMPTY(&mon_fdset->fds) && QLIST_EMPTY(&mon_fdset->dup_fds)) {
         QLIST_REMOVE(mon_fdset, next);
         g_free(mon_fdset);
     }
@@ -2578,6 +2579,86 @@ FdsetInfoList *qmp_query_fdsets(Error **errp)
     return fdset_list;
 }
 
+int monitor_fdset_get_fd(int64_t fdset_id, int flags)
+{
+    MonFdset *mon_fdset;
+    MonFdsetFd *mon_fdset_fd;
+    int mon_fd_flags;
+
+    QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
+        if (mon_fdset->id != fdset_id) {
+            continue;
+        }
+        QLIST_FOREACH(mon_fdset_fd, &mon_fdset->fds, next) {
+            mon_fd_flags = fcntl(mon_fdset_fd->fd, F_GETFL);
+            if (mon_fd_flags == -1) {
+                return -1;
+            }
+
+            if ((flags & O_ACCMODE) == (mon_fd_flags & O_ACCMODE)) {
+                return mon_fdset_fd->fd;
+            }
+        }
+        errno = EACCES;
+        return -1;
+    }
+    errno = ENOENT;
+    return -1;
+}
+
+int monitor_fdset_dup_fd_add(int64_t fdset_id, int dup_fd)
+{
+    MonFdset *mon_fdset;
+    MonFdsetFd *mon_fdset_fd_dup;
+
+    QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
+        if (mon_fdset->id != fdset_id) {
+            continue;
+        }
+        QLIST_FOREACH(mon_fdset_fd_dup, &mon_fdset->dup_fds, next) {
+            if (mon_fdset_fd_dup->fd == dup_fd) {
+                return -1;
+            }
+        }
+        mon_fdset_fd_dup = g_malloc0(sizeof(*mon_fdset_fd_dup));
+        mon_fdset_fd_dup->fd = dup_fd;
+        QLIST_INSERT_HEAD(&mon_fdset->dup_fds, mon_fdset_fd_dup, next);
+        return 0;
+    }
+    return -1;
+}
+
+static int monitor_fdset_dup_fd_find_remove(int dup_fd, bool remove)
+{
+    MonFdset *mon_fdset;
+    MonFdsetFd *mon_fdset_fd_dup;
+
+    QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
+        QLIST_FOREACH(mon_fdset_fd_dup, &mon_fdset->dup_fds, next) {
+            if (mon_fdset_fd_dup->fd == dup_fd) {
+                if (remove) {
+                    QLIST_REMOVE(mon_fdset_fd_dup, next);
+                    if (QLIST_EMPTY(&mon_fdset->dup_fds)) {
+                        monitor_fdset_cleanup(mon_fdset);
+                    }
+                }
+                return mon_fdset->id;
+            }
+        }
+    }
+    return -1;
+}
+
+int monitor_fdset_dup_fd_find(int dup_fd)
+{
+    return monitor_fdset_dup_fd_find_remove(dup_fd, false);
+}
+
+int monitor_fdset_dup_fd_remove(int dup_fd)
+{
+    return monitor_fdset_dup_fd_find_remove(dup_fd, true);
+}
+
 /* mon_cmds and info_cmds would be sorted at runtime */
 static mon_cmd_t mon_cmds[] = {
 #include "hmp-commands.h"
diff --git a/monitor.h b/monitor.h
index 5f4de1b..30b660f 100644
--- a/monitor.h
+++ b/monitor.h
@@ -86,4 +86,9 @@ int qmp_qom_set(Monitor *mon, const QDict *qdict, QObject **ret);
 
 int qmp_qom_get(Monitor *mon, const QDict *qdict, QObject **ret);
 
+int monitor_fdset_get_fd(int64_t fdset_id, int flags);
+int monitor_fdset_dup_fd_add(int64_t fdset_id, int dup_fd);
+int monitor_fdset_dup_fd_remove(int dup_fd);
+int monitor_fdset_dup_fd_find(int dup_fd);
+
 #endif /* !MONITOR_H */
diff --git a/osdep.c b/osdep.c
index 7f876ae..2688af5 100644
--- a/osdep.c
+++ b/osdep.c
@@ -48,6 +48,7 @@ extern int madvise(caddr_t, size_t, int);
 #include "qemu-common.h"
 #include "trace.h"
 #include "qemu_socket.h"
+#include "monitor.h"
 
 static bool fips_enabled = false;
 
@@ -78,6 +79,64 @@ int qemu_madvise(void *addr, size_t len, int advice)
 #endif
 }
 
+/*
+ * Dups an fd and sets the flags
+ */
+static int qemu_dup_flags(int fd, int flags)
+{
+    int ret;
+    int serrno;
+    int dup_flags;
+    int setfl_flags;
+
+#ifdef F_DUPFD_CLOEXEC
+    ret = fcntl(fd, F_DUPFD_CLOEXEC, 0);
+#else
+    ret = dup(fd);
+    if (ret != -1) {
+        qemu_set_cloexec(ret);
+    }
+#endif
+    if (ret == -1) {
+        goto fail;
+    }
+
+    dup_flags = fcntl(ret, F_GETFL);
+    if (dup_flags == -1) {
+        goto fail;
+    }
+
+    if ((flags & O_SYNC) != (dup_flags & O_SYNC)) {
+        errno = EINVAL;
+        goto fail;
+    }
+
+    /* Set/unset flags that we can with fcntl */
+    setfl_flags = O_APPEND | O_ASYNC | O_DIRECT | O_NOATIME | O_NONBLOCK;
+    dup_flags &= ~setfl_flags;
+    dup_flags |= (flags & setfl_flags);
+    if (fcntl(ret, F_SETFL, dup_flags) == -1) {
+        goto fail;
+    }
+
+    /* Truncate the file in the cases that open() would truncate it */
+    if (flags & O_TRUNC ||
+            ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))) {
+        if (ftruncate(ret, 0) == -1) {
+            goto fail;
+        }
+    }
+
+    return ret;
+
+fail:
+    serrno = errno;
+    if (ret != -1) {
+        close(ret);
+    }
+    errno = serrno;
+    return -1;
+}
 
 /*
  * Opens a file with FD_CLOEXEC set
@@ -87,6 +146,41 @@ int qemu_open(const char *name, int flags, ...)
     int ret;
     int mode = 0;
 
+#ifndef _WIN32
+    const char *fdset_id_str;
+
+    /* Attempt dup of fd from fd set */
+    if (strstart(name, "/dev/fdset/", &fdset_id_str)) {
+        int64_t fdset_id;
+        int fd, dupfd;
+
+        fdset_id = qemu_parse_fdset(fdset_id_str);
+        if (fdset_id == -1) {
+            errno = EINVAL;
+            return -1;
+        }
+
+        fd = monitor_fdset_get_fd(fdset_id, flags);
+        if (fd == -1) {
+            return -1;
+        }
+
+        dupfd = qemu_dup_flags(fd, flags);
+        if (dupfd == -1) {
+            return -1;
+        }
+
+        ret = monitor_fdset_dup_fd_add(fdset_id, dupfd);
+        if (ret == -1) {
+            close(dupfd);
+            errno = EINVAL;
+            return -1;
+        }
+
+        return dupfd;
+    }
+#endif
+
     if (flags & O_CREAT) {
         va_list ap;
 
@@ -109,6 +203,21 @@ int qemu_open(const char *name, int flags, ...)
 
 int qemu_close(int fd)
 {
+    int64_t fdset_id;
+
+    /* Close fd that was dup'd from an fdset */
+    fdset_id = monitor_fdset_dup_fd_find(fd);
+    if (fdset_id != -1) {
+        int ret;
+
+        ret = close(fd);
+        if (ret == 0) {
+            monitor_fdset_dup_fd_remove(fd);
+        }
+
+        return ret;
+    }
+
     return close(fd);
 }
 
diff --git a/qemu-common.h b/qemu-common.h
index 90ddacd..efaefba 100644
--- a/qemu-common.h
+++ b/qemu-common.h
@@ -166,6 +166,7 @@ int qemu_fls(int i);
 int qemu_fdatasync(int fd);
 int fcntl_setfl(int fd, int flag);
 int qemu_parse_fd(const char *param);
+int qemu_parse_fdset(const char *param);
 
 /*
  * strtosz() suffixes used to specify the default treatment of an
diff --git a/qemu-tool.c b/qemu-tool.c
index 64b5e88..18205ba 100644
--- a/qemu-tool.c
+++ b/qemu-tool.c
@@ -62,6 +62,26 @@ void monitor_protocol_event(MonitorEvent event, QObject *data)
 {
 }
 
+int monitor_fdset_get_fd(int64_t fdset_id, int flags)
+{
+    return -1;
+}
+
+int monitor_fdset_dup_fd_add(int64_t fdset_id, int dup_fd)
+{
+    return -1;
+}
+
+int monitor_fdset_dup_fd_remove(int dup_fd)
+{
+    return -1;
+}
+
+int monitor_fdset_dup_fd_find(int dup_fd)
+{
+    return -1;
+}
+
 int64_t cpu_get_clock(void)
 {
     return qemu_get_clock_ns(rt_clock);
-- 
1.7.10.4

[Qemu-devel] [PATCH v10 7/7] monitor: Clean up fd sets on monitor disconnect

[Corey Bryant]

Fd sets are shared by all monitor connections.  Fd sets are considered
to be in use while at least one monitor is connected.  When the last
monitor disconnects, all fds that are members of an fd set with no
outstanding dup references are closed.  This prevents any fd leakage
associated with a client disconnect prior to using a passed fd.

Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com>
---
v5:
 -This patch is new in v5.
 -This support addresses concerns from v4 regarding fd leakage
  if the client disconnects unexpectedly. (eblake@redhat.com,
  kwolf@redhat.com, dberrange@redhat.com)

v6:
 -No changes

v7:
 -Removed monitor_fdsets_set_in_use() function since we now use
  mon_refcount to determine if fdsets are in use.
 -Added monitor_fdsets_cleanup() function, and increment/decrement
  of mon_refcount when monitor connects/disconnects.

v8:
 -Use camel case for structures. (stefanha@linux.vnet.ibm.com)

v9:
 -Define mon_refcount and add corresponding logic to
  monitor_fdset_cleanup here rather than earlier patch.
  (kwolf@redhat.com)

v10:
 -No changes

 monitor.c |   23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/monitor.c b/monitor.c
index f56d6a1..0a4fa38 100644
--- a/monitor.c
+++ b/monitor.c
@@ -230,6 +230,7 @@ static inline int mon_print_count_get(const Monitor *mon) { return 0; }
 
 static QLIST_HEAD(mon_list, Monitor) mon_list;
 static QLIST_HEAD(mon_fdsets, MonFdset) mon_fdsets;
+static int mon_refcount;
 
 static mon_cmd_t mon_cmds[];
 static mon_cmd_t info_cmds[];
@@ -2414,7 +2415,8 @@ static void monitor_fdset_cleanup(MonFdset *mon_fdset)
     MonFdsetFd *mon_fdset_fd_next;
 
     QLIST_FOREACH_SAFE(mon_fdset_fd, &mon_fdset->fds, next, mon_fdset_fd_next) {
-        if (mon_fdset_fd->removed) {
+        if (mon_fdset_fd->removed ||
+                (QLIST_EMPTY(&mon_fdset->dup_fds) && mon_refcount == 0)) {
             close(mon_fdset_fd->fd);
             g_free(mon_fdset_fd->opaque);
             QLIST_REMOVE(mon_fdset_fd, next);
@@ -2428,6 +2430,16 @@ static void monitor_fdset_cleanup(MonFdset *mon_fdset)
     }
 }
 
+static void monitor_fdsets_cleanup(void)
+{
+    MonFdset *mon_fdset;
+    MonFdset *mon_fdset_next;
+
+    QLIST_FOREACH_SAFE(mon_fdset, &mon_fdsets, next, mon_fdset_next) {
+        monitor_fdset_cleanup(mon_fdset);
+    }
+}
+
 AddfdInfo *qmp_add_fd(bool has_fdset_id, int64_t fdset_id, bool has_opaque,
                       const char *opaque, Error **errp)
 {
@@ -4863,9 +4875,12 @@ static void monitor_control_event(void *opaque, int event)
         data = get_qmp_greeting();
         monitor_json_emitter(mon, data);
         qobject_decref(data);
+        mon_refcount++;
         break;
     case CHR_EVENT_CLOSED:
         json_message_parser_destroy(&mon->mc->parser);
+        mon_refcount--;
+        monitor_fdsets_cleanup();
         break;
     }
 }
@@ -4906,6 +4921,12 @@ static void monitor_event(void *opaque, int event)
             readline_show_prompt(mon->rs);
         }
         mon->reset_seen = 1;
+        mon_refcount++;
+        break;
+
+    case CHR_EVENT_CLOSED:
+        mon_refcount--;
+        monitor_fdsets_cleanup();
         break;
     }
 }
-- 
1.7.10.4

Re: [Qemu-devel] [PATCH v10 0/7] file descriptor passing using fd sets

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 876 bytes --]

On 08/13/2012 08:08 AM, Corey Bryant wrote:
> libvirt's sVirt security driver provides SELinux MAC isolation for
> Qemu guest processes and their corresponding image files.  In other
> words, sVirt uses SELinux to prevent a QEMU process from opening
> files that do not belong to it.
> 

> Corey Bryant (7):
>   qemu-char: Add MSG_CMSG_CLOEXEC flag to recvmsg
>   qapi: Introduce add-fd, remove-fd, query-fdsets
>   block: Prevent detection of /dev/fdset/ as floppy
>   block: Convert open calls to qemu_open
>   block: Convert close calls to qemu_close
>   block: Enable qemu_open/close to work with fd sets
>   monitor: Clean up fd sets on monitor disconnect

Hooray - I think we're there!  Series:

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake@redhat.com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 620 bytes --]

Re: [Qemu-devel] [PATCH v10 0/7] file descriptor passing using fd sets

[Corey Bryant]

On 08/13/2012 02:02 PM, Eric Blake wrote:
> On 08/13/2012 08:08 AM, Corey Bryant wrote:
>> libvirt's sVirt security driver provides SELinux MAC isolation for
>> Qemu guest processes and their corresponding image files.  In other
>> words, sVirt uses SELinux to prevent a QEMU process from opening
>> files that do not belong to it.
>>
>
>> Corey Bryant (7):
>>    qemu-char: Add MSG_CMSG_CLOEXEC flag to recvmsg
>>    qapi: Introduce add-fd, remove-fd, query-fdsets
>>    block: Prevent detection of /dev/fdset/ as floppy
>>    block: Convert open calls to qemu_open
>>    block: Convert close calls to qemu_close
>>    block: Enable qemu_open/close to work with fd sets
>>    monitor: Clean up fd sets on monitor disconnect
>
> Hooray - I think we're there!  Series:
>
> Reviewed-by: Eric Blake <eblake@redhat.com>
>

Thanks again!!

Btw, In the case that no new versions of the patches need to be 
submitted, how does your Reviewed-by get added?  Do I need to do 
anything to add it?

-- 
Regards,
Corey

Re: [Qemu-devel] [PATCH v10 0/7] file descriptor passing using fd sets

[Kevin Wolf]

Am 13.08.2012 20:39, schrieb Corey Bryant:
> 
> 
> On 08/13/2012 02:02 PM, Eric Blake wrote:
>> On 08/13/2012 08:08 AM, Corey Bryant wrote:
>>> libvirt's sVirt security driver provides SELinux MAC isolation for
>>> Qemu guest processes and their corresponding image files.  In other
>>> words, sVirt uses SELinux to prevent a QEMU process from opening
>>> files that do not belong to it.
>>>
>>
>>> Corey Bryant (7):
>>>    qemu-char: Add MSG_CMSG_CLOEXEC flag to recvmsg
>>>    qapi: Introduce add-fd, remove-fd, query-fdsets
>>>    block: Prevent detection of /dev/fdset/ as floppy
>>>    block: Convert open calls to qemu_open
>>>    block: Convert close calls to qemu_close
>>>    block: Enable qemu_open/close to work with fd sets
>>>    monitor: Clean up fd sets on monitor disconnect

Thanks, applied all to the block branch.

>> Hooray - I think we're there!  Series:
>>
>> Reviewed-by: Eric Blake <eblake@redhat.com>
>>
> 
> Thanks again!!
> 
> Btw, In the case that no new versions of the patches need to be 
> submitted, how does your Reviewed-by get added?  Do I need to do 
> anything to add it?

No, I picked it up.

Kevin

Re: [Qemu-devel] [PATCH v10 6/7] block: Enable qemu_open/close to work with fd sets

[Kevin Wolf]

Am 13.08.2012 16:08, schrieb Corey Bryant:
> When qemu_open is passed a filename of the "/dev/fdset/nnn"
> format (where nnn is the fdset ID), an fd with matching access
> mode flags will be searched for within the specified monitor
> fd set.  If the fd is found, a dup of the fd will be returned
> from qemu_open.
> 
> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com>

>  cutils.c      |    5 +++
>  monitor.c     |   83 ++++++++++++++++++++++++++++++++++++++++++-
>  monitor.h     |    5 +++
>  osdep.c       |  109 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  qemu-common.h |    1 +
>  qemu-tool.c   |   20 +++++++++++
>  6 files changed, 222 insertions(+), 1 deletion(-)

This breaks the build of vscclient and the qtest cases, because osdep.c
has now a new dependency on the fdset monitor functions. The easy way to
fix it would be to squash the following in (linking vscclient and qtests
with qemu-tool.o). Any objections?

Kevin


diff --git a/Makefile b/Makefile
index d736ea5..a11a7f4 100644
--- a/Makefile
+++ b/Makefile
@@ -148,9 +148,6 @@ install-libcacard: libcacard.la
        $(call quiet-command,$(MAKE) $(SUBDIR_MAKEFLAGS) -C libcacard
V="$(V)" TARGET_DIR="$*/" install-libcacard,)
 endif

-vscclient$(EXESUF): $(libcacard-y) $(oslib-obj-y) $(trace-obj-y)
qemu-timer-common.o libcacard/vscclient.o
-       $(call quiet-command,$(CC) $(LDFLAGS) -o $@ $^ $(libcacard_libs)
$(LIBS),"  LINK  $@")
-
 ######################################################################

 qemu-img.o: qemu-img-cmds.h
@@ -166,6 +163,9 @@ qemu-io$(EXESUF): qemu-io.o cmd.o $(tools-obj-y)
$(block-obj-y)

 qemu-bridge-helper$(EXESUF): qemu-bridge-helper.o

+vscclient$(EXESUF): $(tools-obj-y) $(libcacard-y) $(oslib-obj-y)
$(trace-obj-y) qemu-timer-common.o libcacard/vscclient.o
+       $(call quiet-command,$(CC) $(LDFLAGS) -o $@ $^ $(libcacard_libs)
$(LIBS),"  LINK  $@")
+
 fsdev/virtfs-proxy-helper$(EXESUF): fsdev/virtfs-proxy-helper.o
fsdev/virtio-9p-marshal.o oslib-posix.o $(trace-obj-y)
 fsdev/virtfs-proxy-helper$(EXESUF): LIBS += -lcap

diff --git a/tests/Makefile b/tests/Makefile
index f3f4159..26a67ce 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -81,7 +81,7 @@ TARGETS=$(patsubst %-softmmu,%, $(filter
%-softmmu,$(TARGET_DIRS)))
 QTEST_TARGETS=$(foreach TARGET,$(TARGETS), $(if
$(check-qtest-$(TARGET)-y), $(TARGET),))
 check-qtest-$(CONFIG_POSIX)=$(foreach TARGET,$(TARGETS),
$(check-qtest-$(TARGET)-y))

-qtest-obj-y = tests/libqtest.o $(oslib-obj-y)
+qtest-obj-y = tests/libqtest.o $(oslib-obj-y) $(tools-obj-y)
 $(check-qtest-y): $(qtest-obj-y)

 .PHONY: check-help

Re: [Qemu-devel] [PATCH v10 6/7] block: Enable qemu_open/close to work with fd sets

[Corey Bryant]

On 08/14/2012 08:07 AM, Kevin Wolf wrote:
> Am 13.08.2012 16:08, schrieb Corey Bryant:
>> When qemu_open is passed a filename of the "/dev/fdset/nnn"
>> format (where nnn is the fdset ID), an fd with matching access
>> mode flags will be searched for within the specified monitor
>> fd set.  If the fd is found, a dup of the fd will be returned
>> from qemu_open.
>>
>> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com>
>
>>   cutils.c      |    5 +++
>>   monitor.c     |   83 ++++++++++++++++++++++++++++++++++++++++++-
>>   monitor.h     |    5 +++
>>   osdep.c       |  109 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>   qemu-common.h |    1 +
>>   qemu-tool.c   |   20 +++++++++++
>>   6 files changed, 222 insertions(+), 1 deletion(-)
>
> This breaks the build of vscclient and the qtest cases, because osdep.c
> has now a new dependency on the fdset monitor functions. The easy way to
> fix it would be to squash the following in (linking vscclient and qtests
> with qemu-tool.o). Any objections?
>
> Kevin
>

Sorry about that.  Now I know to run make check. :)  I don't have any 
objections to this fix.  I ran my tests again with this and there 
weren't any problems.

-- 
Regards,
Corey