[Qemu-devel] [PATCH 2/2] Dump: add command "fuse-mount"

[Nan Li <nli@suse.com>]

Add a "fuse-mount" command to support the Filesystem in Userspace (FUSE).
It can mount or unmount the filesystem with both hmp and qmp commands.
It calls the API function qemu_fuse_main(int argc, char *argv[]).

Signed-off-by: Nan Li <nli@suse.com>
---
 dump.c           | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 hmp-commands.hx  | 19 +++++++++++++++++++
 hmp.c            | 12 ++++++++++++
 hmp.h            |  1 +
 qapi-schema.json | 15 +++++++++++++++
 qmp-commands.hx  | 31 +++++++++++++++++++++++++++++++
 6 files changed, 126 insertions(+)

diff --git a/dump.c b/dump.c
index 9726f1f..7599f06 100644
--- a/dump.c
+++ b/dump.c
@@ -26,6 +26,10 @@
 #include "qapi/qmp/qerror.h"
 #include "qmp-commands.h"
 #include "qapi-event.h"
+#ifdef CONFIG_FUSE
+#include <sys/mount.h>
+#include "fuse-mem.h"
+#endif
 
 #include <zlib.h>
 #ifdef CONFIG_LZO
@@ -1846,3 +1850,47 @@ DumpGuestMemoryCapability *qmp_query_dump_guest_memory_capability(Error **errp)
 
     return cap;
 }
+
+#ifdef CONFIG_FUSE
+static void *fuse_process(void *data)
+{
+    pid_t pid;
+    int argc = 2;
+    char *argv[2];
+    char programname[] = "fuse-mount-process";
+    argv[0] = programname;
+    argv[1] = (char *)data;
+    int ret;
+
+    if ((pid = fork()) < 0)
+        perror("fork() is failed");
+    else if (pid == 0) {
+        ret = qemu_fuse_main(argc, argv);
+        if ( ret != 0 )
+            perror("qemu_fuse_main() is failed");
+        exit(0);
+    }
+    return NULL;
+}
+
+void qmp_fuse_mount(bool unmount, const char *mountpoint, Error **errp)
+{
+    int ret;
+
+    if (unmount) {
+        ret = umount(mountpoint);
+        if (ret < 0) {
+            error_setg(errp, "umount() is failed");
+        }
+        return;
+    }
+
+    char * prot = g_strdup(mountpoint);
+    fuse_process((void *)prot);
+}
+#else
+void qmp_fuse_mount(bool unmount, const char *mountpoint, Error **errp)
+{
+    abort();
+}
+#endif
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 4f4f60a..746db0c 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1087,6 +1087,25 @@ gdb. Without -z|-l|-s, the dump format is ELF.
             together with begin.
 ETEXI
 
+#if defined(CONFIG_FUSE)
+    {
+        .name       = "fuse-mount",
+        .args_type  = "unmount:-u,mountpoint:s",
+        .params     = "[-u] mountpoint",
+        .help       = "mount(unmount) fuse system on 'mountpoint'.\n\t\t\t"
+                      "-u: unmount.",
+        .mhandler.cmd = hmp_fuse_mount,
+    },
+
+STEXI
+@item fuse-mount [-u] @var{mountpoint}
+@findex fuse-mount
+Mount(unmount) fuse system to @var{mountpoint}.
+        -u: unmount.
+  mountpoint: the mount point (a path) of fuse system.
+ETEXI
+#endif
+
 #if defined(TARGET_S390X)
     {
         .name       = "dump-skeys",
diff --git a/hmp.c b/hmp.c
index d510236..884e8a3 100644
--- a/hmp.c
+++ b/hmp.c
@@ -1643,6 +1643,18 @@ void hmp_dump_guest_memory(Monitor *mon, const QDict *qdict)
     g_free(prot);
 }
 
+#ifdef CONFIG_FUSE
+void hmp_fuse_mount(Monitor *mon, const QDict *qdict)
+{
+    Error *err = NULL;
+    bool unmount = qdict_get_try_bool(qdict, "unmount", false);
+    const char *mountpoint = qdict_get_str(qdict, "mountpoint");
+
+    qmp_fuse_mount(unmount, mountpoint, &err);
+    hmp_handle_error(mon, &err);
+}
+#endif
+
 void hmp_netdev_add(Monitor *mon, const QDict *qdict)
 {
     Error *err = NULL;
diff --git a/hmp.h b/hmp.h
index 093d65f..f183fe9 100644
--- a/hmp.h
+++ b/hmp.h
@@ -85,6 +85,7 @@ void hmp_migrate(Monitor *mon, const QDict *qdict);
 void hmp_device_add(Monitor *mon, const QDict *qdict);
 void hmp_device_del(Monitor *mon, const QDict *qdict);
 void hmp_dump_guest_memory(Monitor *mon, const QDict *qdict);
+void hmp_fuse_mount(Monitor *mon, const QDict *qdict);
 void hmp_netdev_add(Monitor *mon, const QDict *qdict);
 void hmp_netdev_del(Monitor *mon, const QDict *qdict);
 void hmp_getfd(Monitor *mon, const QDict *qdict);
diff --git a/qapi-schema.json b/qapi-schema.json
index e58f6a9..d268019 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -2283,6 +2283,21 @@
   'returns': 'DumpGuestMemoryCapability' }
 
 ##
+# @fuse-mount:
+#
+# mount(unmount) fuse system on 'mountpoint'.
+#
+# @is_mount: optional if true, umount the fuse system from the mount point
+#
+# @mountpoint: the mount point (a path) of fuse system
+#
+# Returns: Nothing on success
+#
+# Since: 2.6
+##
+{ 'command': 'fuse-mount', 'data': {'unmount': 'bool', 'mountpoint': 'str'} }
+
+##
 # @dump-skeys
 #
 # Dump guest's storage keys
diff --git a/qmp-commands.hx b/qmp-commands.hx
index de896a5..efcf6c1 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -921,6 +921,37 @@ Example:
 
 EQMP
 
+#if defined(CONFIG_FUSE)
+    {
+        .name       = "fuse-mount",
+        .args_type  = "unmount:b,mountpoint:s",
+        .params     = "[-u] mountpoint",
+        .help       = "mount(unmount) fuse system on 'mountpoint'.\n\t\t\t"
+                      "-u: unmount.",
+        .mhandler.cmd_new = qmp_marshal_fuse_mount,
+    },
+SQMP
+fuse-mount
+
+mount(unmount) fuse system on 'mountpoint'.
+
+Arguments:
+
+- "unmount": unmount the fuse system (json-bool)
+- "mountpoint": the mount point (a path) of fuse system (json-string)
+
+Example:
+
+-> { "execute": "fuse-mount", "arguments": { "mountpoint": "/etc/qemu/fuse" } }
+<- { "return": {} }
+
+Notes:
+
+(1) All boolean arguments default to false
+
+EQMP
+#endif
+
 #if defined TARGET_S390X
     {
         .name       = "dump-skeys",
-- 
1.8.4.5