Re: [libvirt] [RFC] [PATCH 2/5] add fuse support for libvirt lxc

this patch addes fuse support for libvirt lxc. we can use fuse filesystem to generate sysinfo dynamically, So we can isolate /proc/meminfo,cpuinfo and so on through fuse filesystem. we mount fuse filesystem for every container.the mount name is Lxc-lxcname-fuse. Signed-off-by: Gao feng <gaofeng(a)cn.fujitsu.com&gt; --- src/Makefile.am | 9 ++- src/lxc/lxc_controller.c | 15 +++++ src/lxc/lxc_driver.c | 2 + src/lxc/lxc_fuse.c | 155 ++++++++++++++++++++++++++++++++++++++++++++++ src/lxc/lxc_fuse.h | 38 +++++++++++ 5 files changed, 217 insertions(+), 2 deletions(-) create mode 100644 src/lxc/lxc_fuse.c create mode 100644 src/lxc/lxc_fuse.h diff --git a/src/Makefile.am b/src/Makefile.am index 6c3eaa7..b01b2df 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -349,11 +349,13 @@ endif LXC_DRIVER_SOURCES = \ lxc/lxc_conf.c lxc/lxc_conf.h \ + lxc/lxc_fuse.c lxc/lxc_fuse.h \ lxc/lxc_container.c lxc/lxc_container.h \ lxc/lxc_driver.c lxc/lxc_driver.h LXC_CONTROLLER_SOURCES = \ lxc/lxc_conf.c lxc/lxc_conf.h \ + lxc/lxc_fuse.c lxc/lxc_fuse.h \ lxc/lxc_container.c lxc/lxc_container.h \ lxc/lxc_controller.c @@ -819,8 +821,9 @@ endif libvirt_driver_lxc_impl_la_CFLAGS = \ $(LIBNL_CFLAGS) \ + $(FUSE_CFLAGS) \ -I$(top_srcdir)/src/conf $(AM_CFLAGS) -libvirt_driver_lxc_impl_la_LIBADD = $(CAPNG_LIBS) $(LIBNL_LIBS) +libvirt_driver_lxc_impl_la_LIBADD = $(CAPNG_LIBS) $(LIBNL_LIBS) $(FUSE_LIBS) if HAVE_LIBBLKID libvirt_driver_lxc_impl_la_CFLAGS += $(BLKID_CFLAGS) libvirt_driver_lxc_impl_la_LIBADD += $(BLKID_LIBS) @@ -1523,6 +1526,7 @@ libvirt_lxc_SOURCES = \ libvirt_lxc_LDFLAGS = $(WARN_CFLAGS) $(AM_LDFLAGS) libvirt_lxc_LDADD = \ $(NUMACTL_LIBS) \ + $(FUSE_LIBS) \ libvirt-net-rpc-server.la \ libvirt-net-rpc.la \ libvirt_driver_security.la \ @@ -1540,7 +1544,8 @@ libvirt_lxc_LDADD += $(APPARMOR_LIBS) endif libvirt_lxc_CFLAGS = \ -I$(top_srcdir)/src/conf \ - $(AM_CFLAGS) + $(AM_CFLAGS) \ + $(FUSE_CFLAGS) if HAVE_LIBBLKID libvirt_lxc_CFLAGS += $(BLKID_CFLAGS) libvirt_lxc_LDADD += $(BLKID_LIBS) diff --git a/src/lxc/lxc_controller.c b/src/lxc/lxc_controller.c index a4874ea..44ba07c 100644 --- a/src/lxc/lxc_controller.c +++ b/src/lxc/lxc_controller.c @@ -58,6 +58,7 @@ #include "lxc_conf.h" #include "lxc_container.h" +#include "lxc_fuse.h" #include "virnetdev.h" #include "virnetdevveth.h" #include "memory.h" @@ -1741,6 +1742,20 @@ int main(int argc, char *argv[]) } } + if ((pid = fork()) < 0) + goto cleanup; + + if (pid == 0) { + if ((pid = fork()) < 0) + _exit(-1); + + if (pid > 0) + _exit(0); + + lxcRegisterFuse(ctrl->def); + _exit(0); + }

+#if HAVE_FUSE + +static int lxcProcGetattr(const char *path, struct stat *stbuf) +{ + int res = 0; + + memset(stbuf, 0, sizeof(struct stat)); + if (strcmp(path, "/") == 0) {

+ stbuf->st_mode = S_IFDIR | 0755; + stbuf->st_nlink = 2; + } else + res = -ENOENT;

+ + return res; +} + +static int lxcProcReaddir(const char *path, void *buf, + fuse_fill_dir_t filler, + off_t offset ATTRIBUTE_UNUSED, + struct fuse_file_info *fi ATTRIBUTE_UNUSED) +{ + if (strcmp(path, "/") != 0) + return -ENOENT; + + filler(buf, ".", NULL, 0); + filler(buf, "..", NULL, 0); + + return 0; +} + +static int lxcProcOpen(const char *path ATTRIBUTE_UNUSED, + struct fuse_file_info *fi ATTRIBUTE_UNUSED) +{ + return -ENOENT; +} + +static int lxcProcRead(const char *path ATTRIBUTE_UNUSED, + char *buf ATTRIBUTE_UNUSED, + size_t size ATTRIBUTE_UNUSED, + off_t offset ATTRIBUTE_UNUSED, + struct fuse_file_info *fi ATTRIBUTE_UNUSED) +{ + return -ENOENT; +} + +static struct fuse_operations lxcProcOper = { + .getattr = lxcProcGetattr, + .readdir = lxcProcReaddir, + .open = lxcProcOpen, + .read = lxcProcRead, +}; + +int lxcRegisterFuse(virDomainDefPtr def) +{ + int rc = -1; + char *path = NULL; + char *name = NULL; + int argc = 3; + char *argv[argc]; + + if ((rc = virAsprintf(&name, "Lxc-%s-fuse", def->name)) < 0) { + virReportOOMError(); + goto cleanup; + } + + if ((rc = virAsprintf(&path, "%s/%s/", LXC_STATE_DIR, def->name)) < 0) { + virReportOOMError(); + goto cleanup; + } + + if ((rc = virFileMakePath(path)) < 0) { + virReportSystemError(errno, _("Cannot create %s"), path); + goto cleanup; + } + + argv[0] = name; + argv[1] = path; + argv[2] = (char *)"-odirect_io"; + + if ((rc = fuse_main(argc, argv, &lxcProcOper, def)) < 0) { + virReportSystemError(errno, "%s", _("Cannot start fuse\n")); + goto cleanup; + } + rc = 0; + +cleanup: + VIR_FREE(name); + VIR_FREE(path); + VIR_FREE(argv); + return rc; +} + +void lxcUnregisterFuse(virDomainDefPtr def) +{ + char *path = NULL; + if (virAsprintf(&path, "%s/%s/", LXC_STATE_DIR, def->name) < 0) { + virReportOOMError(); + return; + } + + if (umount(path) < 0) + virReportSystemError(errno, "%s", _("umount fuse filesystem failed\n")); + + VIR_FREE(path); +} + +#else +int lxcRegisterFuse(virDomainDefPtr def) +{ + (void) def; + return 0; +} + +void lxcUnregisterFuse(virDomainDefPtr def) +{ + (void) def; +} +#endif