[libvirt] [PATCH RFC 6/7] qemu: Spawn qemu under mount namespace

Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- src/qemu/qemu_domain.c | 233 ++++++++++++++++++++++++++++++++++++++++++++++++ src/qemu/qemu_domain.h | 8 ++ src/qemu/qemu_process.c | 13 +++ 3 files changed, 254 insertions(+) diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index 8cba755..3a0170c 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -55,6 +55,7 @@ #include <sys/time.h> #include <fcntl.h> +#include <sys/mount.h> #include <libxml/xpathInternals.h> @@ -86,6 +87,21 @@ VIR_ENUM_IMPL(qemuDomainAsyncJob, QEMU_ASYNC_JOB_LAST, "start", ); +#define QEMU_DEV_MAJ_MEMORY 1 +#define QEMU_DEV_MAJ_TTY 5 +#define QEMU_DEV_MAJ_KVM 10 +#define QEMU_DEV_MAJ_PTY 136 + +#define QEMU_DEV_MIN_CONSOLE 1 +#define QEMU_DEV_MIN_FULL 7 +#define QEMU_DEV_MIN_FUSE 229 +#define QEMU_DEV_MIN_KVM 232 +#define QEMU_DEV_MIN_NULL 3 +#define QEMU_DEV_MIN_PTMX 2 +#define QEMU_DEV_MIN_RANDOM 8 +#define QEMU_DEV_MIN_TTY 0 +#define QEMU_DEV_MIN_URANDOM 9 +#define QEMU_DEV_MIN_ZERO 5 struct _qemuDomainLogContext { int refs; @@ -6658,3 +6674,220 @@ qemuDomainSupportsVideoVga(virDomainVideoDefPtr video, return true; } + + +static int +qemuDomainPopulateDevices(virQEMUDriverPtr driver ATTRIBUTE_UNUSED, + virDomainObjPtr vm ATTRIBUTE_UNUSED, + const char *path) +{ + int ret = -1; + virFileDevices devs[] = { + { QEMU_DEV_MAJ_MEMORY, QEMU_DEV_MIN_NULL, 0666, "/null" }, + { QEMU_DEV_MAJ_MEMORY, QEMU_DEV_MIN_ZERO, 0666, "/zero" }, + { QEMU_DEV_MAJ_MEMORY, QEMU_DEV_MIN_FULL, 0666, "/full" }, + { QEMU_DEV_MAJ_KVM, QEMU_DEV_MIN_KVM, 0660, "/kvm"}, + { QEMU_DEV_MAJ_MEMORY, QEMU_DEV_MIN_RANDOM, 0666, "/random" }, + { QEMU_DEV_MAJ_MEMORY, QEMU_DEV_MIN_URANDOM, 0666, "/urandom" }, + { QEMU_DEV_MAJ_TTY, QEMU_DEV_MIN_TTY, 0666, "/tty" }, + { 0, 0, 0, NULL}, + }; + + if (virFilePopulateDevices(path, devs) < 0) + goto cleanup; + + ret = 0; + cleanup: + return ret; +} + + +static int +qemuDomainSetupDev(virQEMUDriverPtr driver, + virDomainObjPtr vm, + const char *path) +{ + char *mount_options = NULL; + char *opts = NULL; + int ret = -1; + + VIR_DEBUG("Setting up /dev/ for domain %s", vm->def->name); + + mount_options = virSecurityManagerGetMountOptions(driver->securityManager, + vm->def); + + if (!mount_options && + VIR_STRDUP(mount_options, "") < 0) + goto cleanup; + + /* + * tmpfs is limited to 64kb, since we only have device nodes in there + * and don't want to DOS the entire OS RAM usage + */ + if (virAsprintf(&opts, + "mode=755,size=65536%s", mount_options) < 0) + goto cleanup; + + if (virFileSetupDev(path, opts) < 0) + goto cleanup; + + if (qemuDomainPopulateDevices(driver, vm, path) < 0) + goto cleanup; + + ret = 0; + cleanup: + VIR_FREE(opts); + VIR_FREE(mount_options); + return ret; +} + + +static int +qemuDomainSetupDevPTS(virQEMUDriverPtr driver, + virDomainObjPtr vm, + const char *path) +{ + char *mount_options = NULL; + char *opts = NULL; + int ret = -1; + const gid_t ptsgid = 5; + + mount_options = virSecurityManagerGetMountOptions(driver->securityManager, + vm->def); + + if (!mount_options && + VIR_STRDUP(mount_options, "") < 0) + goto cleanup; + + if (virAsprintf(&opts, "newinstance,ptmxmode=0666,mode=0620,gid=%u%s", + ptsgid, (mount_options ? mount_options : "")) < 0) + goto cleanup; + + if (virFileSetupDevPTS(path, opts, NULL) < 0) + goto cleanup; + + ret = 0; + cleanup: + VIR_FREE(opts); + VIR_FREE(mount_options); + return ret; +} + + +int +qemuDomainBuildNamespace(virQEMUDriverPtr driver, + virDomainObjPtr vm) +{ + virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver); + const unsigned long mount_flags = MS_MOVE; + char *devPath = NULL; + char *devptsPath = NULL; + int ret = -1; + + if (virAsprintf(&devPath, "%s/%s.dev", + cfg->stateDir, vm->def->name) < 0 || + virAsprintf(&devptsPath, "%s/%s.devpts", + cfg->stateDir, vm->def->name) < 0) + goto cleanup; + + if (qemuDomainSetupDev(driver, vm, devPath) < 0) + goto cleanup; + + if (mount(devPath, "/dev", NULL, mount_flags, NULL) < 0) { + virReportSystemError(errno, + _("Failed to mount %s on /dev"), + devPath); + goto cleanup; + } + + if (qemuDomainSetupDevPTS(driver, vm, devptsPath) < 0) + goto cleanup; + + if (virFileMakePath("/dev/pts") < 0) { + virReportSystemError(errno, "%s", + _("Cannot create /dev/pts")); + goto cleanup; + } + + if (mount(devptsPath, "/dev/pts", NULL, mount_flags, NULL) < 0) { + virReportSystemError(errno, + _("Failed to mount %s on /dev/pts"), + devptsPath); + goto cleanup; + } + + if (virFileBindMountDevice("/dev/pts/ptmx", "/dev/ptmx") < 0) + goto cleanup; + + VIR_DEBUG("blaaah: %d", system("ls -l /dev > /tmp/blaaah")); + VIR_DEBUG("blaaah: %d", system("ls -l /dev/pts >> /tmp/blaaah")); + VIR_DEBUG("blaaah: %d", system("mount >> /tmp/blaaah")); + ret = 0; + cleanup: + VIR_FREE(devPath); + return ret; +} + + +int +qemuDomainCreateNamespace(virQEMUDriverPtr driver, + virDomainObjPtr vm) +{ + virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver); + int ret = -1; + char *path = NULL; + + if (virAsprintf(&path, "%s/%s.dev", + cfg->stateDir, vm->def->name) < 0) + goto cleanup; + + if (virFileMakePath(path) < 0) { + virReportSystemError(errno, + _("Failed to create %s"), + path); + goto cleanup; + } + + VIR_FREE(path); + if (virAsprintf(&path, "%s/%s.devpts", + cfg->stateDir, vm->def->name) < 0) + goto cleanup; + + if (virFileMakePath(path) < 0) { + virReportSystemError(errno, + _("Failed to create %s"), + path); + goto cleanup; + } + + ret = 0; + cleanup: + VIR_FREE(path); + virObjectUnref(cfg); + return ret; +} + + +void +qemuDomainDeleteNamespace(virQEMUDriverPtr driver, + virDomainObjPtr vm) +{ + virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver); + char *path; + + if (virAsprintf(&path, "%s/%s.dev", + cfg->stateDir, vm->def->name) < 0) + goto cleanup; + + virFileDeleteTree(path); + + VIR_FREE(path); + if (virAsprintf(&path, "%s/%s.devpts", + cfg->stateDir, vm->def->name) < 0) + goto cleanup; + + virFileDeleteTree(path); + cleanup: + virObjectUnref(cfg); + VIR_FREE(path); +} diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h index 0c1689b..8e6d199 100644 --- a/src/qemu/qemu_domain.h +++ b/src/qemu/qemu_domain.h @@ -784,4 +784,12 @@ int qemuDomainCheckMonitor(virQEMUDriverPtr driver, bool qemuDomainSupportsVideoVga(virDomainVideoDefPtr video, virQEMUCapsPtr qemuCaps); +int qemuDomainBuildNamespace(virQEMUDriverPtr driver, + virDomainObjPtr vm); + +int qemuDomainCreateNamespace(virQEMUDriverPtr driver, + virDomainObjPtr vm); + +void qemuDomainDeleteNamespace(virQEMUDriverPtr driver, + virDomainObjPtr vm); #endif /* __QEMU_DOMAIN_H__ */ diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index 09b2a72..522ac19 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -2664,6 +2664,12 @@ static int qemuProcessHook(void *data) if (virSecurityManagerClearSocketLabel(h->driver->securityManager, h->vm->def) < 0) goto cleanup; + if (virProcessSetupPrivateNS() < 0) + goto cleanup; + + if (qemuDomainBuildNamespace(h->driver, h->vm) < 0) + goto cleanup; + if (virDomainNumatuneGetMode(h->vm->def->numa, -1, &mode) == 0) { if (mode == VIR_DOMAIN_NUMATUNE_MEM_STRICT && h->cfg->cgroupControllers & (1 << VIR_CGROUP_CONTROLLER_CPUSET) && @@ -5431,6 +5437,11 @@ qemuProcessLaunch(virConnectPtr conn, qemuDomainLogContextMarkPosition(logCtxt); + VIR_DEBUG("Building mount namespace"); + + if (qemuDomainCreateNamespace(driver, vm) < 0) + goto cleanup; + VIR_DEBUG("Clear emulator capabilities: %d", cfg->clearEmulatorCapabilities); if (cfg->clearEmulatorCapabilities) @@ -6200,6 +6211,8 @@ void qemuProcessStop(virQEMUDriverPtr driver, } } + qemuDomainDeleteNamespace(driver, vm); + vm->taint = 0; vm->pid = -1; virDomainObjSetState(vm, VIR_DOMAIN_SHUTOFF, reason); -- 2.8.4