OpenE2K/qemu-e2k
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qemu-nbd: Add --fork option

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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: Sascha Silbe <silbe@linux.vnet.ibm.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Max Reitz 2016-09-28 22:46:42 +02:00 committed by Kevin Wolf
parent a26ddb4396
commit ffb31e1da7
2 changed files with 18 additions and 1 deletions
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17
qemu-nbd.c
View File

@ -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);

2
qemu-nbd.texi
View File

@ -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