Re: [libvirt] [Qemu-devel] [PATCH v2 2/4] qapi: Add passfd QMP command

This patch adds the passfd QMP command using the QAPI framework. Like the getfd command, it is used to pass a file descriptor via SCM_RIGHTS. However, the passfd command also returns the received file descriptor, which is a difference in behavior from the getfd command, which returns nothing.

The closefd command can be used to close a file descriptor that was passed with the passfd command. v2: -Introduce new QMP command to pass/return fd (lcapitulino(a)redhat.com) -Use passfd as command name (berrange(a)redhat.com) Signed-off-by: Corey Bryant <coreyb(a)linux.vnet.ibm.com&gt; --- monitor.c | 14 ++++++++++---- qapi-schema.json | 15 +++++++++++++++ qmp-commands.hx | 27 +++++++++++++++++++++++++++ 3 files changed, 52 insertions(+), 4 deletions(-) diff --git a/monitor.c b/monitor.c index 4c53cb6..980a226 100644 --- a/monitor.c +++ b/monitor.c @@ -2182,7 +2182,7 @@ static void do_inject_mce(Monitor *mon, const QDict *qdict) } #endif -void qmp_getfd(const char *fdname, Error **errp) +int64_t qmp_passfd(const char *fdname, Error **errp) { mon_fd_t *monfd; int fd; @@ -2190,13 +2190,13 @@ void qmp_getfd(const char *fdname, Error **errp) fd = qemu_chr_fe_get_msgfd(cur_mon->chr); if (fd == -1) { error_set(errp, QERR_FD_NOT_SUPPLIED); - return; + return -1; } if (qemu_isdigit(fdname[0])) { error_set(errp, QERR_INVALID_PARAMETER_VALUE, "fdname", "a name not starting with a digit"); - return; + return -1; } QLIST_FOREACH(monfd, &cur_mon->fds, next) { @@ -2206,7 +2206,7 @@ void qmp_getfd(const char *fdname, Error **errp) close(monfd->fd); monfd->fd = fd; - return; + return fd; } monfd = g_malloc0(sizeof(mon_fd_t)); @@ -2214,6 +2214,12 @@ void qmp_getfd(const char *fdname, Error **errp) monfd->fd = fd; QLIST_INSERT_HEAD(&cur_mon->fds, monfd, next); + return fd; +} + +void qmp_getfd(const char *fdname, Error **errp) +{ + qmp_passfd(fdname, errp); return; } diff --git a/qapi-schema.json b/qapi-schema.json index 6be1d90..15da1b8 100644 --- a/qapi-schema.json +++ b/qapi-schema.json @@ -1864,6 +1864,21 @@ { 'command': 'netdev_del', 'data': {'id': 'str'} } ## +# @passfd: +# +# Pass a file descriptor via SCM rights and assign it a name +# +# @fdname: file descriptor name +# +# Returns: The QEMU file descriptor that was received +# If file descriptor was not received, FdNotSupplied +# If @fdname is not valid, InvalidParameterType +# +# Since: 1.2.0 +## +{ 'command': 'passfd', 'data': {'fdname': 'str'}, 'returns': 'int' } + +## # @getfd: # # Receive a file descriptor via SCM rights and assign it a name diff --git a/qmp-commands.hx b/qmp-commands.hx index f8c0f68..338a0b3 100644 --- a/qmp-commands.hx +++ b/qmp-commands.hx @@ -869,6 +869,33 @@ Example: EQMP { + .name = "passfd", + .args_type = "fdname:s", + .params = "passfd name", + .help = "pass a file descriptor via SCM rights and assign it a name", + .mhandler.cmd_new = qmp_marshal_input_passfd, + }, + +SQMP +passfd +------ + +Pass a file descriptor via SCM rights and assign it a name. + +Arguments: + +- "fdname": file descriptor name (json-string) + +Return a json-int with the QEMU file descriptor that was received. + +Example: + +-> { "execute": "passfd", "arguments": { "fdname": "fd1" } } +<- { "return": 42 } + +EQMP + + { .name = "getfd", .args_type = "fdname:s", .params = "getfd name",