[libvirt] [RFC PATCH 4/6] LXC: Creating devices for container on host side
Gao feng
gaofeng at cn.fujitsu.com
Mon Mar 11 06:26:50 UTC 2013
user namespace doesn't allow to create devices in
uninit userns. We should create devices on host side.
Signed-off-by: Gao feng <gaofeng at cn.fujitsu.com>
---
src/lxc/lxc_container.c | 47 +++++++--------------------
src/lxc/lxc_controller.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 94 insertions(+), 36 deletions(-)
diff --git a/src/lxc/lxc_container.c b/src/lxc/lxc_container.c
index 92af3e5..58d6ee5 100644
--- a/src/lxc/lxc_container.c
+++ b/src/lxc/lxc_container.c
@@ -681,22 +681,10 @@ static int lxcContainerMountFSDevPTS(virDomainFSDefPtr root)
return rc;
}
-static int lxcContainerPopulateDevices(char **ttyPaths, size_t nttyPaths)
+static int lxcContainerSetupDevices(char **ttyPaths, size_t nttyPaths)
{
size_t i;
const struct {
- int maj;
- int min;
- mode_t mode;
- const char *path;
- } devs[] = {
- { LXC_DEV_MAJ_MEMORY, LXC_DEV_MIN_NULL, 0666, "/dev/null" },
- { LXC_DEV_MAJ_MEMORY, LXC_DEV_MIN_ZERO, 0666, "/dev/zero" },
- { LXC_DEV_MAJ_MEMORY, LXC_DEV_MIN_FULL, 0666, "/dev/full" },
- { LXC_DEV_MAJ_MEMORY, LXC_DEV_MIN_RANDOM, 0666, "/dev/random" },
- { LXC_DEV_MAJ_MEMORY, LXC_DEV_MIN_URANDOM, 0666, "/dev/urandom" },
- };
- const struct {
const char *src;
const char *dst;
} links[] = {
@@ -706,18 +694,6 @@ static int lxcContainerPopulateDevices(char **ttyPaths, size_t nttyPaths)
{ "/proc/self/fd", "/dev/fd" },
};
- /* 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);
- if (mknod(devs[i].path, S_IFCHR, dev) < 0 ||
- chmod(devs[i].path, devs[i].mode)) {
- virReportSystemError(errno,
- _("Failed to make device %s"),
- devs[i].path);
- return -1;
- }
- }
-
for (i = 0 ; i < ARRAY_CARDINALITY(links) ; i++) {
if (symlink(links[i].src, links[i].dst) < 0) {
virReportSystemError(errno,
@@ -737,15 +713,6 @@ static int lxcContainerPopulateDevices(char **ttyPaths, size_t nttyPaths)
_("Failed to bind /dev/pts/ptmx on to /dev/ptmx"));
return -1;
}
- } else {
- /* Legacy devpts, so we need to just use shared one */
- dev_t dev = makedev(LXC_DEV_MAJ_TTY, LXC_DEV_MIN_PTMX);
- if (mknod("/dev/ptmx", S_IFCHR, dev) < 0 ||
- chmod("/dev/ptmx", 0666)) {
- virReportSystemError(errno, "%s",
- _("Failed to make device /dev/ptmx"));
- return -1;
- }
}
for (i = 0 ; i < nttyPaths ; i++) {
@@ -1988,8 +1955,8 @@ static int lxcContainerSetupPivotRoot(virDomainDefPtr vmDef,
if (lxcContainerMountFSDevPTS(root) < 0)
goto cleanup;
- /* Populates device nodes in /dev/ */
- if (lxcContainerPopulateDevices(ttyPaths, nttyPaths) < 0)
+ /* Setup device nodes in /dev/ */
+ if (lxcContainerSetupDevices(ttyPaths, nttyPaths) < 0)
goto cleanup;
/* Sets up any non-root mounts from guest config */
@@ -2306,6 +2273,14 @@ static int lxcContainerChild(void *data)
goto cleanup;
}
+ /* Wait for controller creating devices for container */
+ if (lxcContainerWaitForContinue(argv->monitor) < 0) {
+ virReportSystemError(errno, "%s",
+ _("Failed to read the container continue message"));
+ goto cleanup;
+ }
+ VIR_DEBUG("Received container continue message, create devices success.");
+
ret = 0;
cleanup:
VIR_FREE(ttyPath);
diff --git a/src/lxc/lxc_controller.c b/src/lxc/lxc_controller.c
index f17142f..c6f8c3b 100644
--- a/src/lxc/lxc_controller.c
+++ b/src/lxc/lxc_controller.c
@@ -1092,6 +1092,79 @@ cleanup:
}
+static int virLXCControllerPopulateDevices(virLXCControllerPtr ctrl)
+{
+ size_t i;
+ char *ptmx = NULL;
+ const struct {
+ int maj;
+ int min;
+ mode_t mode;
+ const char *path;
+ } devs[] = {
+ { LXC_DEV_MAJ_MEMORY, LXC_DEV_MIN_NULL, 0666, "/dev/null" },
+ { LXC_DEV_MAJ_MEMORY, LXC_DEV_MIN_ZERO, 0666, "/dev/zero" },
+ { LXC_DEV_MAJ_MEMORY, LXC_DEV_MIN_FULL, 0666, "/dev/full" },
+ { LXC_DEV_MAJ_MEMORY, LXC_DEV_MIN_RANDOM, 0666, "/dev/random" },
+ { LXC_DEV_MAJ_MEMORY, LXC_DEV_MIN_URANDOM, 0666, "/dev/urandom" },
+ };
+ virDomainFSDefPtr root = virDomainGetRootFilesystem(ctrl->def);
+
+ if (root == NULL || root->src == NULL)
+ return 0;
+
+ /* Populate /dev/ with a few important bits */
+ for (i = 0 ; i < ARRAY_CARDINALITY(devs) ; i++) {
+ char *path = NULL;
+ if (virAsprintf(&path, "/proc/%llu/root/%s",
+ (unsigned long long)ctrl->initpid,
+ devs[i].path) < 0) {
+ virReportOOMError();
+ return -1;
+ }
+ dev_t dev = makedev(devs[i].maj, devs[i].min);
+ if (mknod(path, S_IFCHR, dev) < 0 ||
+ chmod(path, devs[i].mode)) {
+ virReportSystemError(errno,
+ _("Failed to make device %s"),
+ path);
+ VIR_FREE(path);
+ return -1;
+ }
+ VIR_FREE(path);
+ }
+
+ if (virAsprintf(&ptmx, "/proc/%llu/root/dev/pts/ptmx",
+ (unsigned long long)ctrl->initpid) < 0) {
+ virReportOOMError();
+ return -1;
+ }
+
+ if (access(ptmx, W_OK)) {
+ char *path = NULL;
+ if (virAsprintf(&path, "/proc/%llu/root/dev/ptmx",
+ (unsigned long long)ctrl->initpid) < 0) {
+ virReportOOMError();
+ VIR_FREE(ptmx);
+ return -1;
+ }
+ /* Legacy devpts, so we need to just use shared one */
+ dev_t dev = makedev(LXC_DEV_MAJ_TTY, LXC_DEV_MIN_PTMX);
+ if (mknod(path, S_IFCHR, dev) < 0 ||
+ chmod(path, 0666)) {
+ virReportSystemError(errno,
+ _("Failed to make device %s"), path);
+ VIR_FREE(path);
+ VIR_FREE(ptmx);
+ return -1;
+ }
+ VIR_FREE(path);
+ }
+ VIR_FREE(ptmx);
+ return 0;
+}
+
+
/**
* virLXCControllerMoveInterfaces
* @nveths: number of interfaces
@@ -1535,6 +1608,16 @@ virLXCControllerRun(virLXCControllerPtr ctrl)
goto cleanup;
}
+ /* Populate devices for container */
+ if (virLXCControllerPopulateDevices(ctrl) < 0)
+ goto cleanup;
+
+ if (lxcContainerSendContinue(control[0]) < 0) {
+ virReportSystemError(errno, "%s",
+ _("Unable to send container continue message"));
+ goto cleanup;
+ }
+
/* Now the container is fully setup... */
/* ...we can close the loop devices... */
--
1.7.11.7
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