[PATCH 4/5] kvm tools: Teach 'run' to handle guestfs

[Sasha Levin]

This patch allows to run previously created guestfs by simply specifying it
with the '-d' parameter.

This allows running guestfs which were created before using:

        kvm setup -n [name]

Signed-off-by: Sasha Levin <levinsasha...@gmail.com>
---
 tools/kvm/builtin-run.c     |   24 ++++++++++++++++++++++--
 tools/kvm/include/kvm/kvm.h |    3 +++
 tools/kvm/kvm.c             |    2 --
 3 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/tools/kvm/builtin-run.c b/tools/kvm/builtin-run.c
index ef1a358..725c23c 100644
--- a/tools/kvm/builtin-run.c
+++ b/tools/kvm/builtin-run.c
@@ -85,6 +85,7 @@ static bool vnc;
 static bool sdl;
 static bool balloon;
 static bool using_rootfs;
+static bool custom_rootfs;
 extern bool ioport_debug;
 extern int  active_console;
 extern int  debug_iodelay;
@@ -103,6 +104,7 @@ static int img_name_parser(const struct option *opt, const 
char *arg, int unset)
 {
        char *sep;
        struct stat st;
+       char path[PATH_MAX];
 
        if (stat(arg, &st) == 0 &&
            S_ISDIR(st.st_mode)) {
@@ -115,6 +117,21 @@ static int img_name_parser(const struct option *opt, const 
char *arg, int unset)
                return 0;
        }
 
+       snprintf(path, PATH_MAX, "%s%s%s", HOME_DIR, KVM_PID_FILE_PATH, arg);
+
+       if (stat(path, &st) == 0 &&
+           S_ISDIR(st.st_mode)) {
+               char tmp[PATH_MAX];
+
+               if (realpath(path, tmp) == 0 ||
+                   virtio_9p__register(kvm, tmp, "/dev/root") < 0)
+                       die("Unable to initialize virtio 9p");
+               if (virtio_9p__register(kvm, "/", "hostfs") < 0)
+                       die("Unable to initialize virtio 9p");
+               using_rootfs = custom_rootfs = 1;
+               return 0;
+       }
+
        if (image_count >= MAX_DISK_IMAGES)
                die("Currently only 4 images are supported");
 
@@ -739,10 +756,13 @@ int kvm_cmd_run(int argc, const char **argv, const char 
*prefix)
                        strlcat(real_cmdline, " init=/bin/sh ", 
sizeof(real_cmdline));
        }
 
-       if (using_rootfs)
+       if (using_rootfs) {
                strcat(real_cmdline, " root=/dev/root rw 
rootflags=rw,trans=virtio,version=9p2000.L rootfstype=9p");
-       else if (!strstr(real_cmdline, "root="))
+               if (custom_rootfs)
+                       strcat(real_cmdline, " init=/virt/init");
+       } else if (!strstr(real_cmdline, "root=")) {
                strlcat(real_cmdline, " root=/dev/vda rw ", 
sizeof(real_cmdline));
+       }
 
        if (image_count) {
                kvm->nr_disks = image_count;
diff --git a/tools/kvm/include/kvm/kvm.h b/tools/kvm/include/kvm/kvm.h
index d471cee..bb40c4c 100644
--- a/tools/kvm/include/kvm/kvm.h
+++ b/tools/kvm/include/kvm/kvm.h
@@ -24,6 +24,9 @@
 #define SIGKVMRESUME           (SIGRTMIN + 5)
 #define SIGKVMMEMSTAT          (SIGRTMIN + 6)
 
+#define KVM_PID_FILE_PATH      "/.kvm-tools/"
+#define HOME_DIR               getenv("HOME")
+
 struct kvm {
        int                     sys_fd;         /* For system ioctls(), i.e. 
/dev/kvm */
        int                     vm_fd;          /* For VM ioctls() */
diff --git a/tools/kvm/kvm.c b/tools/kvm/kvm.c
index bbfdea2..199c9b9 100644
--- a/tools/kvm/kvm.c
+++ b/tools/kvm/kvm.c
@@ -32,8 +32,6 @@
 #include <dirent.h>
 
 #define DEFINE_KVM_EXIT_REASON(reason) [reason] = #reason
-#define KVM_PID_FILE_PATH      "/.kvm-tools/"
-#define HOME_DIR               getenv("HOME")
 
 const char *kvm_exit_reasons[] = {
        DEFINE_KVM_EXIT_REASON(KVM_EXIT_UNKNOWN),
-- 
1.7.6.1

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