--- /dev/null
+/*
+ * cgroup.c: Tools for managing cgroups
+ *
+ * Copyright IBM Corp. 2008
+ *
+ * See COPYING.LIB for the License of this software
+ *
+ * Authors:
+ * Dan Smith <danms@us.ibm.com>
+ */
+#include <config.h>
+
+#include <stdio.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <mntent.h>
+#include <fcntl.h>
+#include <string.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <libgen.h>
+
+#include "internal.h"
+#include "util.h"
+#include "memory.h"
+#include "cgroup.h"
+
+#define DEBUG(fmt,...) VIR_DEBUG(__FILE__, fmt, __VA_ARGS__)
+#define DEBUG0(msg) VIR_DEBUG(__FILE__, "%s", msg)
+
+#define CGROUP_MAX_VAL 512
+
+struct virCgroup {
+ char *path;
+};
+
+const char *supported_controllers[] = {
+ "memory",
+ "devices",
+ NULL
+};
+
+/**
+ * virCgroupFree:
+ *
+ * @group: The group structure to free
+ */
+void virCgroupFree(virCgroupPtr *group)
+{
+ if (*group != NULL) {
+ VIR_FREE((*group)->path);
+ VIR_FREE(*group);
+ *group = NULL;
+ }
+}
+
+static virCgroupPtr virCgroupGetMount(const char *controller)
+{
+ FILE *mounts;
+ struct mntent entry;
+ char buf[CGROUP_MAX_VAL];
+ virCgroupPtr root = NULL;
+
+ if (VIR_ALLOC(root) != 0)
+ return NULL;
+
+ mounts = fopen("/proc/mounts", "r");
+ if (mounts == NULL) {
+ DEBUG0("Unable to open /proc/mounts: %m");
+ goto err;
+ }
+
+ while (getmntent_r(mounts, &entry, buf, sizeof(buf)) != NULL) {
+ if (STREQ(entry.mnt_type, "cgroup") &&
+ (strstr(entry.mnt_opts, controller))) {
+ root->path = strdup(entry.mnt_dir);
+ break;
+ }
+ }
+
+ DEBUG("Mount for %s is %s\n", controller, root->path);
+
+ if (root->path == NULL) {
+ DEBUG0("Did not find cgroup mount");
+ goto err;
+ }
+
+ fclose(mounts);
+
+ return root;
+err:
+ virCgroupFree(&root);
+
+ return NULL;
+}
+
+/**
+ * virCgroupHaveSupport:
+ *
+ * Returns 0 if support is present, negative if not
+ */
+int virCgroupHaveSupport(void)
+{
+ virCgroupPtr root;
+ int i;
+
+ for (i = 0; supported_controllers[i] != NULL; i++) {
+ root = virCgroupGetMount(supported_controllers[i]);
+ if (root == NULL)
+ return -1;
+ virCgroupFree(&root);
+ }
+
+ return 0;
+}
+
+static int virCgroupPathOfGroup(const char *group,
+ const char *controller,
+ char **path)
+{
+ virCgroupPtr root = NULL;
+ int rc = 0;
+
+ root = virCgroupGetMount(controller);
+ if (root == NULL) {
+ rc = -ENOTDIR;
+ goto out;
+ }
+
+ if (asprintf(path, "%s/%s", root->path, group) == -1)
+ rc = -ENOMEM;
+out:
+ virCgroupFree(&root);
+
+ return rc;
+}
+
+static int virCgroupPathOf(const char *grppath,
+ const char *key,
+ char **path)
+{
+ virCgroupPtr root;
+ int rc = 0;
+ char *controller = NULL;
+
+ if (strchr(key, '.') == NULL)
+ return -EINVAL;
+
+ if (sscanf(key, "%a[^.]", &controller) != 1)
+ return -EINVAL;
+
+ root = virCgroupGetMount(controller);
+ if (root == NULL) {
+ rc = -ENOTDIR;
+ goto out;
+ }
+
+ if (asprintf(path, "%s/%s/%s", root->path, grppath, key) == -1)
+ rc = -ENOMEM;
+out:
+ virCgroupFree(&root);
+ VIR_FREE(controller);
+
+ return rc;
+}
+
+static int virCgroupSetValueStr(virCgroupPtr group,
+ const char *key,
+ const char *value)
+{
+ int fd = -1;
+ int rc = 0;
+ char *keypath = NULL;
+
+ rc = virCgroupPathOf(group->path, key, &keypath);
+ if (rc != 0)
+ return rc;
+
+ fd = open(keypath, O_WRONLY);
+ if (fd < 0) {
+ DEBUG("Unable to open %s: %m", keypath);
+ rc = -ENOENT;
+ goto out;
+ }
+
+ DEBUG("Writing '%s' to '%s'", value, keypath);
+
+ rc = safewrite(fd, value, strlen(value));
+ if (rc < 0) {
+ DEBUG("Failed to write value '%s': %m", value);
+ rc = -errno;
+ goto out;
+ } else if (rc != strlen(value)) {
+ DEBUG("Short write of value '%s'", value);
+ rc = -ENOSPC;
+ goto out;
+ }
+
+ rc = 0;
+out:
+ VIR_FREE(keypath);
+ close(fd);
+
+ return rc;
+}
+
+static int virCgroupSetValueU64(virCgroupPtr group,
+ const char *key,
+ uint64_t value)
+{
+ char *strval = NULL;
+ int rc;
+
+ if (asprintf(&strval, "%" PRIu64, value) == -1)
+ return -ENOMEM;
+
+ rc = virCgroupSetValueStr(group, key, strval);
+
+ VIR_FREE(strval);
+
+ return rc;
+}
+
+#if 0
+/* This is included for completeness, but not yet used */
+
+static int virCgroupSetValueI64(virCgroupPtr group,
+ const char *key,
+ int64_t value)
+{
+ char *strval = NULL;
+ int rc;
+
+ if (asprintf(&strval, "%" PRIi64, value) == -1)
+ return -ENOMEM;
+
+ rc = virCgroupSetValueStr(group, key, strval);
+
+ VIR_FREE(strval);
+
+ return rc;
+}
+
+static int virCgroupGetValueStr(virCgroupPtr group,
+ const char *key,
+ char **value)
+{
+ int fd = -1;
+ int rc;
+ char *keypath = NULL;
+ char buf[CGROUP_MAX_VAL];
+
+ memset(buf, 0, sizeof(buf));
+
+ rc = virCgroupPathOf(group->path, key, &keypath);
+ if (rc != 0) {
+ DEBUG("No path of %s, %s", group->path, key);
+ return rc;
+ }
+
+ fd = open(keypath, O_RDONLY);
+ if (fd < 0) {
+ DEBUG("Unable to open %s: %m", keypath);
+ rc = -ENOENT;
+ goto out;
+ }
+
+ rc = saferead(fd, buf, sizeof(buf));
+ if (rc < 0) {
+ DEBUG("Failed to read %s: %m\n", keypath);
+ rc = -errno;
+ goto out;
+ } else if (rc == 0) {
+ DEBUG("Short read of %s\n", keypath);
+ rc = -EIO;
+ goto out;
+ }
+
+ *value = strdup(buf);
+ if (*value == NULL) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ rc = 0;
+out:
+ VIR_FREE(keypath);
+ close(fd);
+
+ return rc;
+}
+
+static int virCgroupGetValueU64(virCgroupPtr group,
+ const char *key,
+ uint64_t *value)
+{
+ char *strval = NULL;
+ int rc = 0;
+
+ rc = virCgroupGetValueStr(group, key, &strval);
+ if (rc != 0)
+ goto out;
+
+ if (sscanf(strval, "%" SCNu64, value) != 1)
+ rc = -EINVAL;
+out:
+ VIR_FREE(strval);
+
+ return rc;
+}
+
+static int virCgroupGetValueI64(virCgroupPtr group,
+ const char *key,
+ int64_t *value)
+{
+ char *strval = NULL;
+ int rc = 0;
+
+ rc = virCgroupGetValueStr(group, key, &strval);
+ if (rc != 0)
+ goto out;
+
+ if (sscanf(strval, "%" SCNi64, value) != 1)
+ rc = -EINVAL;
+out:
+ VIR_FREE(strval);
+
+ return rc;
+}
+#endif
+
+static int _virCgroupInherit(const char *path,
+ const char *key)
+{
+ int rc = 0;
+ int fd = -1;
+ char buf[CGROUP_MAX_VAL];
+ char *keypath = NULL;
+ char *pkeypath = NULL;
+
+ memset(buf, 0, sizeof(buf));
+
+ if (asprintf(&keypath, "%s/%s", path, key) == -1) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ if (access(keypath, F_OK) != 0) {
+ DEBUG("Group %s has no key %s\n", path, key);
+ goto out;
+ }
+
+ if (asprintf(&pkeypath, "%s/../%s", path, key) == -1) {
+ rc = -ENOMEM;
+ VIR_FREE(keypath);
+ goto out;
+ }
+
+ fd = open(pkeypath, O_RDONLY);
+ if (fd < 0) {
+ rc = -errno;
+ goto out;
+ }
+
+ if (saferead(fd, buf, sizeof(buf)) <= 0) {
+ rc = -errno;
+ goto out;
+ }
+
+ close(fd);
+
+ fd = open(keypath, O_WRONLY);
+ if (fd < 0) {
+ rc = -errno;
+ goto out;
+ }
+
+ if (safewrite(fd, buf, strlen(buf)) != strlen(buf)) {
+ rc = -errno;
+ goto out;
+ }
+
+out:
+ VIR_FREE(keypath);
+ VIR_FREE(pkeypath);
+ close(fd);
+
+ return rc;
+}
+
+static int virCgroupInherit(const char *grppath)
+{
+ int i;
+ int rc = 0;
+ const char *inherit_values[] = {
+ "cpuset.cpus",
+ "cpuset.mems",
+ NULL
+ };
+
+ for (i = 0; inherit_values[i] != NULL; i++) {
+ const char *key = inherit_values[i];
+
+ rc = _virCgroupInherit(grppath, key);
+ if (rc != 0) {
+ DEBUG("inherit of %s failed\n", key);
+ break;
+ }
+ }
+
+ return rc;
+}
+
+static int virCgroupMakeGroup(const char *name)
+{
+ int i;
+ int rc = 0;
+
+ for (i = 0; supported_controllers[i] != NULL; i++) {
+ char *path = NULL;
+ virCgroupPtr root;
+
+ root = virCgroupGetMount(supported_controllers[i]);
+ if (root == NULL)
+ continue;
+
+ rc = virCgroupPathOfGroup(name, supported_controllers[i], &path);
+ if (rc != 0) {
+ virCgroupFree(&root);
+ break;
+ }
+
+ virCgroupFree(&root);
+
+ if (access(path, F_OK) != 0) {
+ if (mkdir(path, 0655) < 0) {
+ rc = -errno;
+ VIR_FREE(path);
+ break;
+ }
+ virCgroupInherit(path);
+ }
+
+ VIR_FREE(path);
+ }
+
+ return rc;
+}
+
+static int virCgroupRoot(virCgroupPtr *root)
+{
+ int rc = 0;
+ char *grppath = NULL;
+
+ if (VIR_ALLOC((*root)) != 0) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ (*root)->path = strdup("libvirt");
+ if ((*root)->path == NULL) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ rc = virCgroupMakeGroup((*root)->path);
+out:
+ if (rc != 0)
+ virCgroupFree(root);
+ VIR_FREE(grppath);
+
+ return rc;
+}
+
+static int virCgroupNew(virCgroupPtr *parent,
+ const char *group,
+ virCgroupPtr *newgroup)
+{
+ int rc = 0;
+ char *typpath = NULL;
+
+ *newgroup = NULL;
+
+ if (*parent == NULL) {
+ rc = virCgroupRoot(parent);
+ if (rc != 0)
+ goto err;
+ }
+
+ if (VIR_ALLOC((*newgroup)) != 0) {
+ rc = -ENOMEM;
+ goto err;
+ }
+
+ rc = asprintf(&((*newgroup)->path),
+ "%s/%s",
+ (*parent)->path,
+ group);
+ if (rc == -1) {
+ rc = -ENOMEM;
+ goto err;
+ }
+
+ rc = 0;
+
+ return rc;
+err:
+ virCgroupFree(newgroup);
+ *newgroup = NULL;
+
+ VIR_FREE(typpath);
+
+ return rc;
+}
+
+static int virCgroupOpen(virCgroupPtr parent,
+ const char *group,
+ virCgroupPtr *newgroup)
+{
+ int rc = 0;
+ char *grppath = NULL;
+ bool free_parent = (parent == NULL);
+
+ rc = virCgroupNew(&parent, group, newgroup);
+ if (rc != 0)
+ goto err;
+
+ if (free_parent)
+ virCgroupFree(&parent);
+
+ rc = virCgroupPathOfGroup((*newgroup)->path,
+ supported_controllers[0],
+ &grppath);
+ if (rc != 0)
+ goto err;
+
+ if (access(grppath, F_OK) != 0) {
+ rc = -ENOENT;
+ goto err;
+ }
+
+ return rc;
+err:
+ virCgroupFree(newgroup);
+ *newgroup = NULL;
+
+ return rc;
+}
+
+static int virCgroupCreate(virCgroupPtr parent,
+ const char *group,
+ virCgroupPtr *newgroup)
+{
+ int rc = 0;
+ bool free_parent = (parent == NULL);
+
+ rc = virCgroupNew(&parent, group, newgroup);
+ if (rc != 0) {
+ DEBUG0("Unable to allocate new virCgroup structure");
+ goto err;
+ }
+
+ rc = virCgroupMakeGroup((*newgroup)->path);
+ if (rc != 0)
+ goto err;
+
+ if (free_parent)
+ virCgroupFree(&parent);
+
+ return rc;
+err:
+ virCgroupFree(newgroup);
+ *newgroup = NULL;
+
+ if (free_parent)
+ virCgroupFree(&parent);
+
+ return rc;
+}
+
+/**
+ * virCgroupRemove:
+ *
+ * @group: The group to be removed
+ *
+ * Returns: 0 on success
+ */
+int virCgroupRemove(virCgroupPtr group)
+{
+ int rc = 0;
+ int i;
+ char *grppath = NULL;
+
+ for (i = 0; supported_controllers[i] != NULL; i++) {
+ if (virCgroupPathOfGroup(group->path,
+ supported_controllers[i],
+ &grppath) != 0)
+ continue;
+
+ if (rmdir(grppath) != 0)
+ rc = -errno;
+
+ VIR_FREE(grppath);
+ }
+
+ return rc;
+}
+
+/**
+ * virCgroupAddTask:
+ *
+ * @group: The cgroup to add a task to
+ * @pid: The pid of the task to add
+ *
+ * Returns: 0 on success
+ */
+int virCgroupAddTask(virCgroupPtr group, pid_t pid)
+{
+ int rc = 0;
+ int fd = -1;
+ int i;
+ char *grppath = NULL;
+ char *taskpath = NULL;
+ char *pidstr = NULL;
+
+ for (i = 0; supported_controllers[i] != NULL; i++) {
+ rc = virCgroupPathOfGroup(group->path,
+ supported_controllers[i],
+ &grppath);
+ if (rc != 0)
+ goto done;
+
+ if (asprintf(&taskpath, "%s/tasks", grppath) == -1) {
+ rc = -ENOMEM;
+ goto done;
+ }
+
+ fd = open(taskpath, O_WRONLY);
+ if (fd < 0) {
+ rc = -errno;
+ goto done;
+ }
+
+ if (asprintf(&pidstr, "%lu", (unsigned long)pid) == -1) {
+ rc = -ENOMEM;
+ goto done;
+ }
+
+ if (write(fd, pidstr, strlen(pidstr)) <= 0) {
+ rc = -errno;
+ goto done;
+ }
+
+ done:
+ VIR_FREE(grppath);
+ VIR_FREE(taskpath);
+ VIR_FREE(pidstr);
+ close(fd);
+
+ if (rc != 0)
+ break;
+ }
+
+ return rc;
+}
+
+/**
+ * virCgroupForDomain:
+ *
+ * @def: Domain definition to create cgroup for
+ * @driverName: Classification of this domain type (e.g., xen, qemu, lxc)
+ * @group: Pointer to returned virCgroupPtr
+ *
+ * Returns 0 on success
+ */
+int virCgroupForDomain(virDomainDefPtr def,
+ const char *driverName,
+ virCgroupPtr *group)
+{
+ int rc;
+ virCgroupPtr typegrp = NULL;
+
+ rc = virCgroupOpen(NULL, driverName, &typegrp);
+ if (rc == -ENOENT) {
+ rc = virCgroupCreate(NULL, driverName, &typegrp);
+ if (rc != 0)
+ goto out;
+ } else if (rc != 0)
+ goto out;
+
+ rc = virCgroupOpen(typegrp, def->name, group);
+ if (rc == -ENOENT)
+ rc = virCgroupCreate(typegrp, def->name, group);
+out:
+ virCgroupFree(&typegrp);
+
+ return rc;
+}
+
+/**
+ * virCgroupSetMemory:
+ *
+ * @group: The cgroup to change memory for
+ * @kb: The memory amount in kilobytes
+ *
+ * Returns: 0 on success
+ */
+int virCgroupSetMemory(virCgroupPtr group, unsigned long kb)
+{
+ return virCgroupSetValueU64(group,
+ "memory.limit_in_bytes",
+ kb << 10);
+}
+
+/**
+ * virCgroupDenyAllDevices:
+ *
+ * @group: The cgroup to deny devices for
+ *
+ * Returns: 0 on success
+ */
+int virCgroupDenyAllDevices(virCgroupPtr group)
+{
+ return virCgroupSetValueStr(group,
+ "devices.deny",
+ "a");
+}
+
+/**
+ * virCgroupAllowDevice:
+ *
+ * @group: The cgroup to allow a device for
+ * @type: The device type (i.e., 'c' or 'b')
+ * @major: The major number of the device
+ * @minor: The minor number of the device
+ *
+ * Returns: 0 on success
+ */
+int virCgroupAllowDevice(virCgroupPtr group,
+ char type,
+ int major,
+ int minor)
+{
+ int rc;
+ char *devstr = NULL;
+
+ if (asprintf(&devstr, "%c %i:%i rwm", type, major, minor) == -1) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ rc = virCgroupSetValueStr(group,
+ "devices.allow",
+ devstr);
+out:
+ VIR_FREE(devstr);
+
+ return rc;
+}
projects / people / liuw / libxenctrl-split / libvirt.git / commitdiff