[libvirt] [PATCH] Add getfd and closefd monitor commands
Add monitor commands to support passing file descriptors via
SCM_RIGHTS.
getfd assigns the passed file descriptor a name for use with other
monitor commands.
closefd allows passed file descriptors to be closed. If a monitor
command actually uses a named file descriptor, closefd will not be
required.
Signed-off-by: Mark McLoughlin <markmc(a)redhat.com>
---
monitor.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
qemu-monitor.hx | 18 ++++++++++++++
2 files changed, 87 insertions(+), 0 deletions(-)
diff --git a/monitor.c b/monitor.c
index e38c86e..817e4b7 100644
--- a/monitor.c
+++ b/monitor.c
@@ -70,6 +70,14 @@ typedef struct mon_cmd_t {
const char *help;
} mon_cmd_t;
+/* file descriptors passed via SCM_RIGHTS */
+typedef struct mon_fd_t mon_fd_t;
+struct mon_fd_t {
+ char *name;
+ int fd;
+ LIST_ENTRY(mon_fd_t) next;
+};
+
struct Monitor {
CharDriverState *chr;
int flags;
@@ -80,6 +88,7 @@ struct Monitor {
CPUState *mon_cpu;
BlockDriverCompletionFunc *password_completion_cb;
void *password_opaque;
+ LIST_HEAD(,mon_fd_t) fds;
LIST_ENTRY(Monitor) entry;
};
@@ -1705,6 +1714,66 @@ static void do_inject_mce(Monitor *mon,
}
#endif
+static void do_getfd(Monitor *mon, const char *fdname)
+{
+ mon_fd_t *monfd;
+ int fd;
+
+ fd = qemu_chr_get_msgfd(mon->chr);
+ if (fd == -1) {
+ monitor_printf(mon, "getfd: no file descriptor supplied via
SCM_RIGHTS\n");
+ return;
+ }
+
+ if (qemu_isdigit(fdname[0])) {
+ monitor_printf(mon, "getfd: monitor names may not begin with a
number\n");
+ return;
+ }
+
+ fd = dup(fd);
+ if (fd == -1) {
+ monitor_printf(mon, "Failed to dup() file descriptor: %s\n",
+ strerror(errno));
+ return;
+ }
+
+ LIST_FOREACH(monfd, &mon->fds, next) {
+ if (strcmp(monfd->name, fdname) != 0) {
+ continue;
+ }
+
+ close(monfd->fd);
+ monfd->fd = fd;
+ return;
+ }
+
+ monfd = qemu_mallocz(sizeof(mon_fd_t));
+ monfd->name = qemu_strdup(fdname);
+ monfd->fd = fd;
+
+ LIST_INSERT_HEAD(&mon->fds, monfd, next);
+}
+
+static void do_closefd(Monitor *mon, const char *fdname)
+{
+ mon_fd_t *monfd;
+
+ LIST_FOREACH(monfd, &mon->fds, next) {
+ if (strcmp(monfd->name, fdname) != 0) {
+ continue;
+ }
+
+ LIST_REMOVE(monfd, next);
+ close(monfd->fd);
+ qemu_free(monfd->name);
+ qemu_free(monfd);
+ return;
+ }
+
+ monitor_printf(mon, "Failed to find file descriptor named %s\n",
+ fdname);
+}
+
static const mon_cmd_t mon_cmds[] = {
#include "qemu-monitor.h"
{ NULL, NULL, },
diff --git a/qemu-monitor.hx b/qemu-monitor.hx
index 70e2475..11bdb2c 100644
--- a/qemu-monitor.hx
+++ b/qemu-monitor.hx
@@ -628,6 +628,24 @@ STEXI
Inject an MCE on the given CPU (x86 only).
ETEXI
+ { "getfd", "s", do_getfd, "getfd name",
+ "receive a file descriptor via SCM rights and assign it a name" },
+STEXI
+@item getfd @var{fdname}
+If a file descriptor is passed alongside this command using the SCM_RIGHTS
+mechanism on unix sockets, it is stored using the name @var{fdname} for
+later use by other monitor commands.
+ETEXI
+
+ { "closefd", "s", do_closefd, "closefd name",
+ "close a file descriptor previously passed via SCM rights" },
+STEXI
+@item closefd @var{fdname}
+Close the file descriptor previously assigned to @var{fdname} using the
+@code{getfd} command. This is only needed if the file descriptor was never
+used by another monitor command.
+ETEXI
+
STEXI
@end table
ETEXI
--
1.6.2.5