Daniel Veillard wrote:
> On Tue, May 06, 2008 at 12:51:08AM -0700, Dave Leskovec wrote:
[...]
>> - close(vm->parentTty);
>> + //close(vm->parentTty);
>> close(vm->containerTtyFd);
>
> if we really don't need this anymore just remove it, if you have doubts then
> maybe this should be clarified. In any case let's stick to old style comments
> /* ... */
>
That shouldn't be commented out. I've restored it in the attached updated
patch.
--
Best Regards,
Dave Leskovec
IBM Linux Technology Center
Open Virtualization
---
src/lxc_driver.c | 172 ++++++++++++++++++++++++++++++++++++++++---------------
1 file changed, 128 insertions(+), 44 deletions(-)
Index: b/src/lxc_driver.c
===================================================================
--- a/src/lxc_driver.c 2008-05-05 23:21:56.000000000 -0700
+++ b/src/lxc_driver.c 2008-05-07 11:04:38.000000000 -0700
@@ -26,9 +26,10 @@
#ifdef WITH_LXC
#include <fcntl.h>
-#include <poll.h>
+#include <sys/epoll.h>
#include <sched.h>
#include <sys/utsname.h>
+#include <stdbool.h>
#include <string.h>
#include <sys/types.h>
#include <termios.h>
@@ -552,7 +553,7 @@
int rc = -1;
char tempTtyName[PATH_MAX];
- *ttymaster = posix_openpt(O_RDWR|O_NOCTTY);
+ *ttymaster = posix_openpt(O_RDWR|O_NOCTTY|O_NONBLOCK);
if (*ttymaster < 0) {
lxcError(conn, NULL, VIR_ERR_INTERNAL_ERROR,
_("posix_openpt failed: %s"), strerror(errno));
@@ -593,75 +594,155 @@
}
/**
+ * lxcFdForward:
+ * @readFd: file descriptor to read
+ * @writeFd: file desriptor to write
+ *
+ * Reads 1 byte of data from readFd and writes to writeFd.
+ *
+ * Returns 0 on success, EAGAIN if returned on read, or -1 in case of error
+ */
+static int lxcFdForward(int readFd, int writeFd)
+{
+ int rc = -1;
+ char buf[2];
+
+ if (1 != (saferead(readFd, buf, 1))) {
+ if (EAGAIN == errno) {
+ rc = EAGAIN;
+ goto cleanup;
+ }
+
+ lxcError(NULL, NULL, VIR_ERR_INTERNAL_ERROR,
+ _("read of fd %d failed: %s"), readFd, strerror(errno));
+ goto cleanup;
+ }
+
+ if (1 != (safewrite(writeFd, buf, 1))) {
+ lxcError(NULL, NULL, VIR_ERR_INTERNAL_ERROR,
+ _("write to fd %d failed: %s"), writeFd, strerror(errno));
+ goto cleanup;
+ }
+
+ rc = 0;
+
+cleanup:
+ return rc;
+}
+
+typedef struct _lxcTtyForwardFd_t {
+ int fd;
+ bool active;
+} lxcTtyForwardFd_t;
+
+/**
* lxcTtyForward:
* @fd1: Open fd
* @fd1: Open fd
*
* Forwards traffic between fds. Data read from fd1 will be written to fd2
- * Data read from fd2 will be written to fd1. This process loops forever.
+ * This process loops forever.
+ * This uses epoll in edge triggered mode to avoid a hard loop on POLLHUP
+ * events when the user disconnects the virsh console via ctrl-]
*
* Returns 0 on success or -1 in case of error
*/
static int lxcTtyForward(int fd1, int fd2)
{
int rc = -1;
- int i;
- char buf[2];
- struct pollfd fds[2];
- int numFds = 0;
-
- if (0 <= fd1) {
- fds[numFds].fd = fd1;
- fds[numFds].events = POLLIN;
- ++numFds;
+ int epollFd;
+ struct epoll_event epollEvent;
+ int numEvents;
+ int numActive = 0;
+ lxcTtyForwardFd_t fdArray[2];
+ int timeout = -1;
+ int curFdOff = 0;
+ int writeFdOff = 0;
+
+ fdArray[0].fd = fd1;
+ fdArray[0].active = false;
+ fdArray[1].fd = fd2;
+ fdArray[1].active = false;
+
+ /* create the epoll fild descriptor */
+ epollFd = epoll_create(2);
+ if (0 > epollFd) {
+ lxcError(NULL, NULL, VIR_ERR_INTERNAL_ERROR,
+ _("epoll_create(2) failed: %s"), strerror(errno));
+ goto cleanup;
}
- if (0 <= fd2) {
- fds[numFds].fd = fd2;
- fds[numFds].events = POLLIN;
- ++numFds;
+ /* add the file descriptors the epoll fd */
+ memset(&epollEvent, 0x00, sizeof(epollEvent));
+ epollEvent.events = EPOLLIN|EPOLLET; /* edge triggered */
+ epollEvent.data.fd = fd1;
+ epollEvent.data.u32 = 0; /* fdArray position */
+ if (0 > epoll_ctl(epollFd, EPOLL_CTL_ADD, fd1, &epollEvent)) {
+ lxcError(NULL, NULL, VIR_ERR_INTERNAL_ERROR,
+ _("epoll_ctl(fd1) failed: %s"), strerror(errno));
+ goto cleanup;
}
-
- if (0 == numFds) {
- DEBUG0("No fds to monitor, return");
+ epollEvent.data.fd = fd2;
+ epollEvent.data.u32 = 1; /* fdArray position */
+ if (0 > epoll_ctl(epollFd, EPOLL_CTL_ADD, fd2, &epollEvent)) {
+ lxcError(NULL, NULL, VIR_ERR_INTERNAL_ERROR,
+ _("epoll_ctl(fd2) failed: %s"), strerror(errno));
goto cleanup;
}
while (1) {
- if ((rc = poll(fds, numFds, -1)) <= 0) {
+ /* if active fd's, return if no events, else wait forever */
+ timeout = (numActive > 0) ? 0 : -1;
+ numEvents = epoll_wait(epollFd, &epollEvent, 1, timeout);
+ if (0 < numEvents) {
+ if (epollEvent.events & EPOLLIN) {
+ curFdOff = epollEvent.data.u32;
+ if (!fdArray[curFdOff].active) {
+ fdArray[curFdOff].active = true;
+ ++numActive;
+ }
- if ((0 == rc) || (errno == EINTR) || (errno == EAGAIN)) {
+ } else if (epollEvent.events & EPOLLHUP) {
+ DEBUG("EPOLLHUP from fd %d", epollEvent.data.fd);
continue;
+ } else {
+ lxcError(NULL, NULL, VIR_ERR_INTERNAL_ERROR,
+ _("error event %d"), epollEvent.events);
+ goto cleanup;
}
- lxcError(NULL, NULL, VIR_ERR_INTERNAL_ERROR,
- _("poll returned error: %s"), strerror(errno));
- goto cleanup;
- }
+ } else if (0 == numEvents) {
+ if (2 == numActive) {
+ /* both fds active, toggle between the two */
+ curFdOff ^= 1;
+ } else {
+ /* only one active, if current is active, use it, else it */
+ /* must be the other one (ie. curFd just went inactive) */
+ curFdOff = fdArray[curFdOff].active ? curFdOff : curFdOff ^ 1;
+ }
- for (i = 0; i < numFds; ++i) {
- if (!fds[i].revents) {
+ } else {
+ if (EINTR == errno) {
continue;
}
- if (fds[i].revents & POLLIN) {
- if (1 != (saferead(fds[i].fd, buf, 1))) {
- lxcError(NULL, NULL, VIR_ERR_INTERNAL_ERROR,
- _("read of fd %d failed: %s"), i,
- strerror(errno));
- goto cleanup;
- }
-
- if (1 < numFds) {
- if (1 != (safewrite(fds[i ^ 1].fd, buf, 1))) {
- lxcError(NULL, NULL, VIR_ERR_INTERNAL_ERROR,
- _("write to fd %d failed: %s"), i,
- strerror(errno));
- goto cleanup;
- }
+ /* error */
+ lxcError(NULL, NULL, VIR_ERR_INTERNAL_ERROR,
+ _("epoll_wait() failed: %s"), strerror(errno));
+ goto cleanup;
- }
+ }
+ if (0 < numActive) {
+ writeFdOff = curFdOff ^ 1;
+ rc = lxcFdForward(fdArray[curFdOff].fd, fdArray[writeFdOff].fd);
+
+ if (EAGAIN == rc) {
+ /* this fd no longer has data, set it as inactive */
+ --numActive;
+ fdArray[curFdOff].active = false;
+ } else if (-1 == rc) {
+ goto cleanup;
}
}
@@ -671,7 +752,10 @@
rc = 0;
cleanup:
- return rc;
+ close(fd1);
+ close(fd2);
+ close(epollFd);
+ exit(rc);
}
/**
--
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