[libvirt] [PATCH] Don't assume use of /sys/fs/cgroup

From: "Daniel P. Berrange" <berrange(a)redhat.com&gt; The introduction of /sys/fs/cgroup came in fairly recent kernels. Prior to that time distros would pick a custom directory like /cgroup or /dev/cgroup. We need to auto-detect where this is, rather than hardcoding it --- src/lxc/lxc_container.c | 71 +++++++++++++++++++++++++++++++++---------------- src/util/cgroup.h | 2 -- 2 files changed, 48 insertions(+), 25 deletions(-) diff --git a/src/lxc/lxc_container.c b/src/lxc/lxc_container.c index f3a4622..9bc5610 100644 --- a/src/lxc/lxc_container.c +++ b/src/lxc/lxc_container.c @@ -1307,7 +1307,8 @@ static void lxcContainerCGroupFree(struct lxcContainerCGroup *mounts, static int lxcContainerIdentifyCGroups(struct lxcContainerCGroup **mountsret, - size_t *nmountsret) + size_t *nmountsret, + char **root) { FILE *procmnt = NULL; struct mntent mntent; @@ -1321,8 +1322,9 @@ static int lxcContainerIdentifyCGroups(struct lxcContainerCGroup **mountsret, *mountsret = NULL; *nmountsret = 0; + *root = NULL; - VIR_DEBUG("Finding cgroups mount points under %s", VIR_CGROUP_SYSFS_MOUNT); + VIR_DEBUG("Finding cgroups mount points of type cgroup"); if (!(procmnt = setmntent("/proc/mounts", "r"))) { virReportSystemError(errno, "%s", @@ -1332,10 +1334,24 @@ static int lxcContainerIdentifyCGroups(struct lxcContainerCGroup **mountsret, while (getmntent_r(procmnt, &mntent, mntbuf, sizeof(mntbuf)) != NULL) { VIR_DEBUG("Got %s", mntent.mnt_dir); - if (STRNEQ(mntent.mnt_type, "cgroup") || - !STRPREFIX(mntent.mnt_dir, VIR_CGROUP_SYSFS_MOUNT)) + if (STRNEQ(mntent.mnt_type, "cgroup")) continue; + if (!*root) { + char *tmp; + if (!(*root = strdup(mntent.mnt_dir))) { + virReportOOMError(); + goto cleanup; + } + tmp = strrchr(*root, '/'); + *tmp = '\0'; + } else if (!STRPREFIX(mntent.mnt_dir, *root)) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("Cgroup %s is not mounted under %s"), + mntent.mnt_dir, *root); + goto cleanup; + } + /* Skip named mounts with no controller since they're * for application use only ie systemd */ if (strstr(mntent.mnt_opts, "name=")) @@ -1349,14 +1365,14 @@ static int lxcContainerIdentifyCGroups(struct lxcContainerCGroup **mountsret, virReportOOMError(); goto cleanup; } - VIR_DEBUG("Grabbed %s", mntent.mnt_dir); + VIR_DEBUG("Grabbed '%s'", mntent.mnt_dir); } - VIR_DEBUG("Checking for symlinks in %s", VIR_CGROUP_SYSFS_MOUNT); - if (!(dh = opendir(VIR_CGROUP_SYSFS_MOUNT))) { + VIR_DEBUG("Checking for symlinks in %s", *root); + if (!(dh = opendir(*root))) { virReportSystemError(errno, _("Unable to read directory %s"), - VIR_CGROUP_SYSFS_MOUNT); + *root); goto cleanup; } @@ -1370,7 +1386,7 @@ static int lxcContainerIdentifyCGroups(struct lxcContainerCGroup **mountsret, continue; VIR_DEBUG("Checking entry %s", dent->d_name); - if (virAsprintf(&path, "%s/%s", VIR_CGROUP_SYSFS_MOUNT, dent->d_name) < 0) { + if (virAsprintf(&path, "%s/%s", *root, dent->d_name) < 0) { virReportOOMError(); goto cleanup; } @@ -1410,25 +1426,28 @@ cleanup: endmntent(procmnt); VIR_FREE(path); - if (ret < 0) + if (ret < 0) { lxcContainerCGroupFree(mounts, nmounts); + VIR_FREE(*root); + } return ret; } static int lxcContainerMountCGroups(struct lxcContainerCGroup *mounts, size_t nmounts, - char * sec_mount_options) + const char *root, + char *sec_mount_options) { size_t i; char *opts = NULL; - VIR_DEBUG("Mounting cgroups at '%s'", VIR_CGROUP_SYSFS_MOUNT); + VIR_DEBUG("Mounting cgroups at '%s'", root); - if (virFileMakePath(VIR_CGROUP_SYSFS_MOUNT) < 0) { + if (virFileMakePath(root) < 0) { virReportSystemError(errno, _("Unable to create directory %s"), - VIR_CGROUP_SYSFS_MOUNT); + root); return -1; } @@ -1438,11 +1457,11 @@ static int lxcContainerMountCGroups(struct lxcContainerCGroup *mounts, return -1; } - if (mount("tmpfs", VIR_CGROUP_SYSFS_MOUNT, "tmpfs", MS_NOSUID|MS_NODEV|MS_NOEXEC, opts) < 0) { + if (mount("tmpfs", root, "tmpfs", MS_NOSUID|MS_NODEV|MS_NOEXEC, opts) < 0) { VIR_FREE(opts); virReportSystemError(errno, _("Failed to mount %s on %s type %s"), - "tmpfs", VIR_CGROUP_SYSFS_MOUNT, "tmpfs"); + "tmpfs", root, "tmpfs"); return -1; } VIR_FREE(opts); @@ -1467,10 +1486,10 @@ static int lxcContainerMountCGroups(struct lxcContainerCGroup *mounts, } if (mount("cgroup", mounts[i].dir, "cgroup", - 0, mounts[i].dir + strlen(VIR_CGROUP_SYSFS_MOUNT) + 1) < 0) { + 0, mounts[i].dir + strlen(root) + 1) < 0) { virReportSystemError(errno, - _("Failed to mount %s on %s"), - "cgroup", mounts[i].dir); + _("Failed to mount cgroup on '%s'"), + mounts[i].dir); return -1; } } @@ -1493,10 +1512,11 @@ static int lxcContainerSetupPivotRoot(virDomainDefPtr vmDef, struct lxcContainerCGroup *mounts = NULL; size_t nmounts = 0; int ret = -1; + char *cgroupRoot; /* Before pivoting we need to identify any * cgroups controllers that are mounted */ - if (lxcContainerIdentifyCGroups(&mounts, &nmounts) < 0) + if (lxcContainerIdentifyCGroups(&mounts, &nmounts, &cgroupRoot) < 0) return -1; /* Gives us a private root, leaving all parent OS mounts on /.oldroot */ @@ -1519,7 +1539,8 @@ static int lxcContainerSetupPivotRoot(virDomainDefPtr vmDef, /* Now we can re-mount the cgroups controllers in the * same configuration as before */ - if (lxcContainerMountCGroups(mounts, nmounts, sec_mount_options) < 0) + if (lxcContainerMountCGroups(mounts, nmounts, + cgroupRoot, sec_mount_options) < 0) goto cleanup; /* Mounts /dev/pts */ @@ -1542,6 +1563,7 @@ static int lxcContainerSetupPivotRoot(virDomainDefPtr vmDef, cleanup: lxcContainerCGroupFree(mounts, nmounts); + VIR_FREE(cgroupRoot); return ret; } @@ -1555,6 +1577,7 @@ static int lxcContainerSetupExtraMounts(virDomainDefPtr vmDef, int ret = -1; struct lxcContainerCGroup *mounts = NULL; size_t nmounts = 0; + char *cgroupRoot; VIR_DEBUG("def=%p", vmDef); /* @@ -1582,7 +1605,7 @@ static int lxcContainerSetupExtraMounts(virDomainDefPtr vmDef, /* Before replacing /sys we need to identify any * cgroups controllers that are mounted */ - if (lxcContainerIdentifyCGroups(&mounts, &nmounts) < 0) + if (lxcContainerIdentifyCGroups(&mounts, &nmounts, &cgroupRoot) < 0) return -1; /* Gets rid of any existing stuff under /proc, since we need new @@ -1598,7 +1621,8 @@ static int lxcContainerSetupExtraMounts(virDomainDefPtr vmDef, /* Now we can re-mount the cgroups controllers in the * same configuration as before */ - if (lxcContainerMountCGroups(mounts, nmounts, sec_mount_options) < 0) + if (lxcContainerMountCGroups(mounts, nmounts, + cgroupRoot, sec_mount_options) < 0) goto cleanup; VIR_DEBUG("Mounting completed"); @@ -1607,6 +1631,7 @@ static int lxcContainerSetupExtraMounts(virDomainDefPtr vmDef, cleanup: lxcContainerCGroupFree(mounts, nmounts); + VIR_FREE(cgroupRoot); return ret; } diff --git a/src/util/cgroup.h b/src/util/cgroup.h index 68ac232..bb12b40 100644 --- a/src/util/cgroup.h +++ b/src/util/cgroup.h @@ -28,8 +28,6 @@ struct virCgroup; typedef struct virCgroup *virCgroupPtr; -# define VIR_CGROUP_SYSFS_MOUNT "/sys/fs/cgroup" - enum { VIR_CGROUP_CONTROLLER_CPU, VIR_CGROUP_CONTROLLER_CPUACCT, -- 1.7.11.2