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lguest: Reboot support

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Reboot Implemented

(Prevent fd leak, fix style and fix documentation --RR)

Signed-off-by: Balaji Rao <balajirrao@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Balaji Rao
2007-12-28 14:26:24 +05:30
committed by Rusty Russell
parent 5c55841d16
commit ec04b13f67
5 changed files with 50 additions and 7 deletions
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32
Documentation/lguest/lguest.c
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@@ -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