Commit ffb31e1d authored by Max Reitz's avatar Max Reitz Committed by Kevin Wolf
Browse files

qemu-nbd: Add --fork option 



Using the --fork option, one can make qemu-nbd fork the worker process.
The original process will exit on error of the worker or once the worker
enters the main loop.

Suggested-by: default avatarSascha Silbe <silbe@linux.vnet.ibm.com>
Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent a26ddb43

qemu-nbd.c

+16 −1
Original line number Diff line number Diff line
@@ -48,6 +48,7 @@ 
#define QEMU_NBD_OPT_OBJECT        260

#define QEMU_NBD_OPT_TLSCREDS      261

#define QEMU_NBD_OPT_IMAGE_OPTS    262

#define QEMU_NBD_OPT_FORK          263



#define MBR_SIZE 512
@@ -92,6 +93,8 @@ static void usage(const char *name) 
"                            passwords and/or encryption keys\n"

"  -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"

"                            specify tracing options\n"

"  --fork                    fork off the server process and exit the parent\n"

"                            once the server is running\n"

#ifdef __linux__

"Kernel NBD client support:\n"

"  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
@@ -503,6 +506,7 @@ int main(int argc, char **argv) 
        { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },

        { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },

        { "trace", required_argument, NULL, 'T' },

        { "fork", no_argument, NULL, QEMU_NBD_OPT_FORK },

        { NULL, 0, NULL, 0 }

    };

    int ch;
@@ -524,6 +528,8 @@ int main(int argc, char **argv) 
    bool imageOpts = false;

    bool writethrough = true;

    char *trace_file = NULL;

    bool fork_process = false;

    int old_stderr = -1;



    /* The client thread uses SIGTERM to interrupt the server.  A signal

     * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
@@ -715,6 +721,9 @@ int main(int argc, char **argv) 
            g_free(trace_file);

            trace_file = trace_opt_parse(optarg);

            break;

        case QEMU_NBD_OPT_FORK:

            fork_process = true;

            break;

        }

    }
@@ -774,7 +783,7 @@ int main(int argc, char **argv) 
        return 0;

    }



    if (device && !verbose) {

    if ((device && !verbose) || fork_process) {

        int stderr_fd[2];

        pid_t pid;

        int ret;
@@ -797,6 +806,7 @@ int main(int argc, char **argv) 
            ret = qemu_daemon(1, 0);



            /* Temporarily redirect stderr to the parent's pipe...  */

            old_stderr = dup(STDERR_FILENO);

            dup2(stderr_fd[1], STDERR_FILENO);

            if (ret < 0) {

                error_report("Failed to daemonize: %s", strerror(errno));
@@ -960,6 +970,11 @@ int main(int argc, char **argv) 
        exit(EXIT_FAILURE);

    }



    if (fork_process) {

        dup2(old_stderr, STDERR_FILENO);

        close(old_stderr);

    }



    state = RUNNING;

    do {

        main_loop_wait(false);

qemu-nbd.texi

+2 −0
Original line number Diff line number Diff line
@@ -86,6 +86,8 @@ the new style NBD protocol negotiation 
Enable mandatory TLS encryption for the server by setting the ID

of the TLS credentials object previously created with the --object

option.

@item --fork

Fork off the server process and exit the parent once the server is running.

@item -v, --verbose

Display extra debugging information

@item -h, --help