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Use a private /dev/pts instance in containers if kernel is new enough

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This commit is contained in:
Daniel P. Berrange 2009-04-22 14:26:50 +00:00
parent 9c19a898f9
commit 220bcb0535
9 changed files with 269 additions and 82 deletions
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17
ChangeLog
View File

@ -1,3 +1,20 @@
Wed Apr 22 15:27:03 BST 2009 Daniel P. Berrange <berrange@redhat.com>
Use private /dev/pts instance for containers (needs 'newinstance'
mount flag for devpts since 2.6.29 kernels), fallback to shared
instance if not supported
* src/domain_conf.h, src/domain_conf.c: Add a convenient
routine virDomainGetRootFilesystem()
* src/libvirt_private.sym: export virDomainGetRootFilesystem
to drivers
* src/util.c, src/util.h: Add virFileOpenTtyAt() to allow
alternate path to /dev/ptmx to be given
* src/lxc_controller.c: Attempt to setup a private /dev/pts
instance for the container's stdio I/O
* src/lxc_container.h, src/lxc_container.c: Pull in the
private /dev/pts instance setup by controller, and create
a symlink for /dev/ptmx.
Tue Apr 21 20:14:03 BST 2009 Daniel P. Berrange <berrange@redhat.com>
* src/qemu_driver.c: Remove pidfile when domain shuts down and

29
src/domain_conf.c
View File

@ -3066,7 +3066,8 @@ static int
virDomainChrDefFormat(virConnectPtr conn,
virBufferPtr buf,
virDomainChrDefPtr def,
const char *name)
const char *name,
int flags)
{
const char *type = virDomainChrTypeToString(def->type);
@ -3081,6 +3082,7 @@ virDomainChrDefFormat(virConnectPtr conn,
name, type);
if (STREQ(name, "console") &&
def->type == VIR_DOMAIN_CHR_TYPE_PTY &&
!(flags & VIR_DOMAIN_XML_INACTIVE) &&
def->data.file.path) {
virBufferEscapeString(buf, " tty='%s'>\n",
def->data.file.path);
@ -3100,7 +3102,7 @@ virDomainChrDefFormat(virConnectPtr conn,
case VIR_DOMAIN_CHR_TYPE_FILE:
case VIR_DOMAIN_CHR_TYPE_PIPE:
if (def->type != VIR_DOMAIN_CHR_TYPE_PTY ||
def->data.file.path) {
(def->data.file.path && !(flags & VIR_DOMAIN_XML_INACTIVE))) {
virBufferEscapeString(buf, " <source path='%s'/>\n",
def->data.file.path);
}
@ -3481,21 +3483,21 @@ char *virDomainDefFormat(virConnectPtr conn,
goto cleanup;
for (n = 0 ; n < def->nserials ; n++)
if (virDomainChrDefFormat(conn, &buf, def->serials[n], "serial") < 0)
if (virDomainChrDefFormat(conn, &buf, def->serials[n], "serial", flags) < 0)
goto cleanup;
for (n = 0 ; n < def->nparallels ; n++)
if (virDomainChrDefFormat(conn, &buf, def->parallels[n], "parallel") < 0)
if (virDomainChrDefFormat(conn, &buf, def->parallels[n], "parallel", flags) < 0)
goto cleanup;
/* If there's a PV console that's preferred.. */
if (def->console) {
if (virDomainChrDefFormat(conn, &buf, def->console, "console") < 0)
if (virDomainChrDefFormat(conn, &buf, def->console, "console", flags) < 0)
goto cleanup;
} else if (def->nserials != 0) {
/* ..else for legacy compat duplicate the first serial device as a
* console */
if (virDomainChrDefFormat(conn, &buf, def->serials[0], "console") < 0)
if (virDomainChrDefFormat(conn, &buf, def->serials[0], "console", flags) < 0)
goto cleanup;
}
@ -3856,6 +3858,21 @@ const char *virDomainDefDefaultEmulator(virConnectPtr conn,
return emulator;
}
virDomainFSDefPtr virDomainGetRootFilesystem(virDomainDefPtr def)
{
int i;
for (i = 0 ; i < def->nfss ; i++) {
if (def->fss[i]->type != VIR_DOMAIN_FS_TYPE_MOUNT)
continue;
if (STREQ(def->fss[i]->dst, "/"))
return def->fss[i];
}
return NULL;
}
void virDomainObjLock(virDomainObjPtr obj)
{

2
src/domain_conf.h
View File

@ -636,6 +636,8 @@ const char *virDomainDefDefaultEmulator(virConnectPtr conn,
virDomainDefPtr def,
virCapsPtr caps);
virDomainFSDefPtr virDomainGetRootFilesystem(virDomainDefPtr def);
void virDomainObjLock(virDomainObjPtr obj);
void virDomainObjUnlock(virDomainObjPtr obj);

1
src/libvirt_private.syms
View File

@ -79,6 +79,7 @@ virDomainDiskQSort;
virDomainFindByID;
virDomainFindByName;
virDomainFindByUUID;
virDomainGetRootFilesystem;
virDomainGraphicsTypeFromString;
virDomainGraphicsDefFree;
virDomainInputDefFree;

173
src/lxc_container.c
View File

@ -308,7 +308,7 @@ static int lxcContainerPivotRoot(virDomainFSDefPtr root)
/* Create a tmpfs root since old and new roots must be
* on separate filesystems */
if (mount("", oldroot, "tmpfs", 0, NULL) < 0) {
if (mount("tmprootfs", oldroot, "tmpfs", 0, NULL) < 0) {
virReportSystemError(NULL, errno,
_("failed to mount empty tmpfs at %s"),
oldroot);
@ -338,15 +338,9 @@ static int lxcContainerPivotRoot(virDomainFSDefPtr root)
/* Now we chroot into the tmpfs, then pivot into the
* root->src bind-mounted onto '/new' */
if (chroot(oldroot) < 0) {
virReportSystemError(NULL, errno, "%s",
_("failed to chroot into tmpfs"));
goto err;
}
if (chdir("/new") < 0) {
virReportSystemError(NULL, errno, "%s",
_("failed to chdir into /new on tmpfs"));
if (chdir(newroot) < 0) {
virReportSystemError(NULL, errno,
_("failed to chroot into %s"), newroot);
goto err;
}
@ -362,12 +356,6 @@ static int lxcContainerPivotRoot(virDomainFSDefPtr root)
if (chdir("/") < 0)
goto err;
if (umount2(".oldroot", MNT_DETACH) < 0) {
virReportSystemError(NULL, errno, "%s",
_("failed to lazily unmount old root"));
goto err;
}
ret = 0;
err:
@ -377,10 +365,64 @@ err:
return ret;
}
static int lxcContainerMountBasicFS(virDomainFSDefPtr root)
{
const struct {
const char *src;
const char *dst;
const char *type;
} mnts[] = {
{ "/dev", "/dev", "tmpfs" },
{ "/proc", "/proc", "proc" },
{ "/sys", "/sys", "sysfs" },
#if WITH_SELINUX
{ "none", "/selinux", "selinuxfs" },
#endif
};
int i, rc;
char *devpts;
if (virAsprintf(&devpts, "/.oldroot%s/dev/pts", root->src) < 0) {
virReportOOMError(NULL);
return -1;
}
for (i = 0 ; i < ARRAY_CARDINALITY(mnts) ; i++) {
if (virFileMakePath(mnts[i].dst) < 0) {
virReportSystemError(NULL, errno,
_("failed to mkdir %s"),
mnts[i].src);
return -1;
}
if (mount(mnts[i].src, mnts[i].dst, mnts[i].type, 0, NULL) < 0) {
virReportSystemError(NULL, errno,
_("failed to mount %s on %s"),
mnts[i].type, mnts[i].type);
return -1;
}
}
if ((rc = virFileMakePath("/dev/pts") < 0)) {
virReportSystemError(NULL, rc, "%s",
_("cannot create /dev/pts"));
return -1;
}
VIR_DEBUG("Trying to move %s to %s", devpts, "/dev/pts");
if ((rc = mount(devpts, "/dev/pts", NULL, MS_MOVE, NULL)) < 0) {
virReportSystemError(NULL, errno, "%s",
_("failed to mount /dev/pts in container"));
return -1;
}
VIR_FREE(devpts);
return 0;
}
static int lxcContainerPopulateDevices(void)
{
int i;
int rc;
const struct {
int maj;
int min;
@ -395,33 +437,6 @@ static int lxcContainerPopulateDevices(void)
{ LXC_DEV_MAJ_MEMORY, LXC_DEV_MIN_URANDOM, 0666, "/dev/urandom" },
};
if ((rc = virFileMakePath("/dev")) < 0) {
virReportSystemError(NULL, rc, "%s",
_("cannot create /dev/"));
return -1;
}
if (mount("none", "/dev", "tmpfs", 0, NULL) < 0) {
virReportSystemError(NULL, errno, "%s",
_("failed to mount /dev tmpfs"));
return -1;
}
/* Move old devpts into container, since we have to
connect to the master ptmx which was opened in
the parent.
XXX This sucks, we need to figure out how to get our
own private devpts for isolation
*/
if ((rc = virFileMakePath("/dev/pts") < 0)) {
virReportSystemError(NULL, rc, "%s",
_("cannot create /dev/pts"));
return -1;
}
if (mount("devpts", "/dev/pts", "devpts", 0, NULL) < 0) {
virReportSystemError(NULL, errno, "%s",
_("failed to mount /dev/pts in container"));
return -1;
}
/* Populate /dev/ with a few important bits */
for (i = 0 ; i < ARRAY_CARDINALITY(devs) ; i++) {
dev_t dev = makedev(devs[i].maj, devs[i].min);
@ -434,6 +449,23 @@ static int lxcContainerPopulateDevices(void)
}
}
if (access("/dev/pts/ptmx", W_OK) == 0) {
if (symlink("/dev/pts/ptmx", "/dev/ptmx") < 0) {
virReportSystemError(NULL, errno, "%s",
_("failed to create symlink /dev/ptmx to /dev/pts/ptmx"));
return -1;
}
} else {
dev_t dev = makedev(LXC_DEV_MAJ_TTY, LXC_DEV_MIN_PTMX);
if (mknod("/dev/ptmx", 0, dev) < 0 ||
chmod("/dev/ptmx", 0666)) {
virReportSystemError(NULL, errno, "%s",
_("failed to make device /dev/ptmx"));
return -1;
}
}
return 0;
}
@ -493,6 +525,7 @@ static int lxcContainerUnmountOldFS(void)
return -1;
}
while (getmntent_r(procmnt, &mntent, mntbuf, sizeof(mntbuf)) != NULL) {
VIR_DEBUG("Got %s", mntent.mnt_dir);
if (!STRPREFIX(mntent.mnt_dir, "/.oldroot"))
continue;
@ -513,6 +546,7 @@ static int lxcContainerUnmountOldFS(void)
lxcContainerChildMountSort);
for (i = 0 ; i < nmounts ; i++) {
VIR_DEBUG("Umount %s", mounts[i]);
if (umount(mounts[i]) < 0) {
virReportSystemError(NULL, errno,
_("failed to unmount '%s'"),
@ -534,22 +568,23 @@ static int lxcContainerUnmountOldFS(void)
static int lxcContainerSetupPivotRoot(virDomainDefPtr vmDef,
virDomainFSDefPtr root)
{
/* Gives us a private root, leaving all parent OS mounts on /.oldroot */
if (lxcContainerPivotRoot(root) < 0)
return -1;
if (virFileMakePath("/proc") < 0 ||
mount("none", "/proc", "proc", 0, NULL) < 0) {
virReportSystemError(NULL, errno, "%s",
_("failed to mount /proc"));
/* Mounts the core /proc, /sys, /dev, /dev/pts filesystems */
if (lxcContainerMountBasicFS(root) < 0)
return -1;
}
/* Populates device nodes in /dev/ */
if (lxcContainerPopulateDevices() < 0)
return -1;
/* Sets up any non-root mounts from guest config */
if (lxcContainerMountNewFS(vmDef) < 0)
return -1;
/* Gets rid of all remaining mounts from host OS, including /.oldroot itself */
if (lxcContainerUnmountOldFS() < 0)
return -1;
@ -595,18 +630,9 @@ static int lxcContainerSetupExtraMounts(virDomainDefPtr vmDef)
return 0;
}
static int lxcContainerSetupMounts(virDomainDefPtr vmDef)
static int lxcContainerSetupMounts(virDomainDefPtr vmDef,
virDomainFSDefPtr root)
{
int i;
virDomainFSDefPtr root = NULL;
for (i = 0 ; i < vmDef->nfss ; i++) {
if (vmDef->fss[i]->type != VIR_DOMAIN_FS_TYPE_MOUNT)
continue;
if (STREQ(vmDef->fss[i]->dst, "/"))
root = vmDef->fss[i];
}
if (root)
return lxcContainerSetupPivotRoot(vmDef, root);
else
@ -630,6 +656,8 @@ static int lxcContainerChild( void *data )
lxc_child_argv_t *argv = data;
virDomainDefPtr vmDef = argv->config;
int ttyfd;
char *ttyPath;
virDomainFSDefPtr root;
if (NULL == vmDef) {
lxcError(NULL, NULL, VIR_ERR_INTERNAL_ERROR,
@ -637,16 +665,28 @@ static int lxcContainerChild( void *data )
return -1;
}
if (lxcContainerSetupMounts(vmDef) < 0)
return -1;
root = virDomainGetRootFilesystem(vmDef);
ttyfd = open(argv->ttyPath, O_RDWR|O_NOCTTY);
if (root) {
if (virAsprintf(&ttyPath, "%s%s", root->src, argv->ttyPath) < 0) {
virReportOOMError(NULL);
return -1;
}
} else {
if (!(ttyPath = strdup(argv->ttyPath))) {
virReportOOMError(NULL);
return -1;
}
}
ttyfd = open(ttyPath, O_RDWR|O_NOCTTY);
if (ttyfd < 0) {
virReportSystemError(NULL, errno,
_("failed to open %s"),
argv->ttyPath);
_("failed to open tty %s"),
ttyPath);
return -1;
}
VIR_FREE(ttyPath);
if (lxcContainerSetStdio(argv->monitor, ttyfd) < 0) {
close(ttyfd);
@ -654,6 +694,9 @@ static int lxcContainerChild( void *data )
}
close(ttyfd);
if (lxcContainerSetupMounts(vmDef, root) < 0)
return -1;
/* Wait for interface devices to show up */
if (lxcContainerWaitForContinue(argv->monitor) < 0)
return -1;

1
src/lxc_container.h
View File

@ -40,6 +40,7 @@ enum {
#define LXC_DEV_MAJ_TTY 5
#define LXC_DEV_MIN_CONSOLE 1
#define LXC_DEV_MIN_PTMX 2
#define LXC_DEV_MAJ_PTY 136

102
src/lxc_controller.c
View File

@ -33,6 +33,7 @@
#include <fcntl.h>
#include <signal.h>
#include <getopt.h>
#include <sys/mount.h>
#include "virterror_internal.h"
#include "logging.h"
@ -426,6 +427,13 @@ static int lxcControllerCleanupInterfaces(unsigned int nveths,
return 0;
}
#ifndef MS_REC
#define MS_REC 16384
#endif
#ifndef MS_SLAVE
#define MS_SLAVE (1<<19)
#endif
static int
lxcControllerRun(virDomainDefPtr def,
@ -440,6 +448,9 @@ lxcControllerRun(virDomainDefPtr def,
int containerPty;
char *containerPtyPath;
pid_t container = -1;
virDomainFSDefPtr root;
char *devpts = NULL;
char *devptmx = NULL;
if (socketpair(PF_UNIX, SOCK_STREAM, 0, control) < 0) {
virReportSystemError(NULL, errno, "%s",
@ -447,14 +458,91 @@ lxcControllerRun(virDomainDefPtr def,
goto cleanup;
}
if (virFileOpenTty(&containerPty,
&containerPtyPath,
0) < 0) {
virReportSystemError(NULL, errno, "%s",
_("failed to allocate tty"));
goto cleanup;
root = virDomainGetRootFilesystem(def);
/*
* If doing a chroot style setup, we need to prepare
* a private /dev/pts for the child now, which they
* will later move into position.
*
* This is complex because 'virsh console' needs to
* use /dev/pts from the host OS, and the guest OS
* needs to use /dev/pts from the guest.
*
* This means that we (libvirt_lxc) need to see and
* use both /dev/pts instances. We're running in the
* host OS context though and don't want to expose
* the guest OS /dev/pts there.
*
* Thus we call unshare(CLONE_NS) so that we can see
* the guest's new /dev/pts, without it becoming
* visible to the host OS. We also put the root FS
* into slave mode, just in case it was currently
* marked as shared
*/
if (root) {
VIR_DEBUG0("Setting up private /dev/pts");
if (unshare(CLONE_NEWNS) < 0) {
virReportSystemError(NULL, errno, "%s",
_("cannot unshare mount namespace"));
goto cleanup;
}
if (mount("", "/", NULL, MS_SLAVE|MS_REC, NULL) < 0) {
virReportSystemError(NULL, errno, "%s",
_("failed to switch root mount into slave mode"));
goto cleanup;
}
if (virAsprintf(&devpts, "%s/dev/pts", root->src) < 0 ||
virAsprintf(&devptmx, "%s/dev/pts/ptmx", root->src) < 0) {
virReportOOMError(NULL);
goto cleanup;
}
if (virFileMakePath(devpts) < 0) {
virReportSystemError(NULL, errno,
_("failed to make path %s"),
devpts);
goto cleanup;
}
VIR_DEBUG("Mouting 'devpts' on %s", devpts);
if (mount("devpts", devpts, "devpts", 0, "newinstance,ptmxmode=0666") < 0) {
virReportSystemError(NULL, errno,
_("failed to mount devpts on %s"),
devpts);
goto cleanup;
}
if (access(devptmx, R_OK) < 0) {
VIR_WARN0("kernel does not support private devpts, using shared devpts");
VIR_FREE(devptmx);
}
}
if (devptmx) {
VIR_DEBUG("Opening tty on private %s", devptmx);
if (virFileOpenTtyAt(devptmx,
&containerPty,
&containerPtyPath,
0) < 0) {
virReportSystemError(NULL, errno, "%s",
_("failed to allocate tty"));
goto cleanup;
}
} else {
VIR_DEBUG0("Opening tty on shared /dev/ptmx");
if (virFileOpenTty(&containerPty,
&containerPtyPath,
0) < 0) {
virReportSystemError(NULL, errno, "%s",
_("failed to allocate tty"));
goto cleanup;
}
}
if (lxcSetContainerResources(def) < 0)
goto cleanup;
@ -476,6 +564,8 @@ lxcControllerRun(virDomainDefPtr def,
rc = lxcControllerMain(monitor, client, appPty, containerPty);
cleanup:
VIR_FREE(devptmx);
VIR_FREE(devpts);
if (control[0] != -1)
close(control[0]);
if (control[1] != -1)

22
src/util.c
View File

@ -1050,14 +1050,25 @@ int virFileBuildPath(const char *dir,
}
#ifdef __linux__
int virFileOpenTty(int *ttymaster,
char **ttyName,
int rawmode)
{
return virFileOpenTtyAt("/dev/ptmx",
ttymaster,
ttyName,
rawmode);
}
#ifdef __linux__
int virFileOpenTtyAt(const char *ptmx,
int *ttymaster,
char **ttyName,
int rawmode)
{
int rc = -1;
if ((*ttymaster = posix_openpt(O_RDWR|O_NOCTTY|O_NONBLOCK)) < 0)
if ((*ttymaster = open(ptmx, O_RDWR|O_NOCTTY|O_NONBLOCK)) < 0)
goto cleanup;
if (unlockpt(*ttymaster) < 0)
@ -1100,9 +1111,10 @@ cleanup:
}
#else
int virFileOpenTty(int *ttymaster ATTRIBUTE_UNUSED,
char **ttyName ATTRIBUTE_UNUSED,
int rawmode ATTRIBUTE_UNUSED)
int virFileOpenTtyAt(const char *ptmx ATTRIBUTE_UNUSED,
int *ttymaster ATTRIBUTE_UNUSED,
char **ttyName ATTRIBUTE_UNUSED,
int rawmode ATTRIBUTE_UNUSED)
{
return -1;
}

4
src/util.h
View File

@ -103,6 +103,10 @@ int virFileBuildPath(const char *dir,
int virFileOpenTty(int *ttymaster,
char **ttyName,
int rawmode);
int virFileOpenTtyAt(const char *ptmx,
int *ttymaster,
char **ttyName,
int rawmode);
char* virFilePid(const char *dir,
const char *name);