Re: [libvirt] [RFC PATCH 4/6] LXC: Creating devices for container on host side

user namespace doesn't allow to create devices in uninit userns. We should create devices on host side. Signed-off-by: Gao feng <gaofeng(a)cn.fujitsu.com&gt; --- 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;