diff options
Diffstat (limited to 'Documentation/lguest')
| -rw-r--r-- | Documentation/lguest/lguest.c | 32 |
1 files changed, 30 insertions, 2 deletions
diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c index 9b0e322118b5..86cac3e622ab 100644 --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -153,6 +153,9 @@ struct virtqueue void (*handle_output)(int fd, struct virtqueue *me); }; +/* Remember the arguments to the program so we can "reboot" */ +static char **main_args; + /* Since guest is UP and we don't run at the same time, we don't need barriers. * But I include them in the code in case others copy it. */ #define wmb() @@ -1489,7 +1492,9 @@ static void setup_block_file(const char *filename) /* Create stack for thread and run it */ stack = malloc(32768); - if (clone(io_thread, stack + 32768, CLONE_VM, dev) == -1) + /* SIGCHLD - We dont "wait" for our cloned thread, so prevent it from + * becoming a zombie. */ + if (clone(io_thread, stack + 32768, CLONE_VM | SIGCHLD, dev) == -1) err(1, "Creating clone"); /* We don't need to keep the I/O thread's end of the pipes open. */ @@ -1499,7 +1504,21 @@ static void setup_block_file(const char *filename) verbose("device %u: virtblock %llu sectors\n", devices.device_num, cap); } -/* That's the end of device setup. */ +/* That's the end of device setup. :*/ + +/* Reboot */ +static void __attribute__((noreturn)) restart_guest(void) +{ + unsigned int i; + + /* Closing pipes causes the waker thread and io_threads to die, and + * closing /dev/lguest cleans up the Guest. Since we don't track all + * open fds, we simply close everything beyond stderr. */ + for (i = 3; i < FD_SETSIZE; i++) + close(i); + execv(main_args[0], main_args); + err(1, "Could not exec %s", main_args[0]); +} /*L:220 Finally we reach the core of the Launcher, which runs the Guest, serves * its input and output, and finally, lays it to rest. */ @@ -1523,6 +1542,9 @@ static void __attribute__((noreturn)) run_guest(int lguest_fd) char reason[1024] = { 0 }; read(lguest_fd, reason, sizeof(reason)-1); errx(1, "%s", reason); + /* ERESTART means that we need to reboot the guest */ + } else if (errno == ERESTART) { + restart_guest(); /* EAGAIN means the Waker wanted us to look at some input. * Anything else means a bug or incompatible change. */ } else if (errno != EAGAIN) @@ -1571,6 +1593,12 @@ int main(int argc, char *argv[]) /* If they specify an initrd file to load. */ const char *initrd_name = NULL; + /* Save the args: we "reboot" by execing ourselves again. */ + main_args = argv; + /* We don't "wait" for the children, so prevent them from becoming + * zombies. */ + signal(SIGCHLD, SIG_IGN); + /* First we initialize the device list. Since console and network * device receive input from a file descriptor, we keep an fdset * (infds) and the maximum fd number (max_infd) with the head of the |