int lxc_attach_proc_to_cgroups(pid_t pid, struct lxc_proc_context_info *ctx)
{
int i, ret;
if (!ctx) {
ERROR("No valid context supplied when asked to attach "
"process to cgroups.");
return -1;
}
for (i = 0; i < ctx->cgroups_count; i++) {
char *path;
/* the kernel should return paths that start with '/' */
if (ctx->cgroups[i].cgroup[0] != '/') {
ERROR("For cgroup subsystem(s) %s the path '%s' does "
"not start with a '/'",
ctx->cgroups[i].subsystems,
ctx->cgroups[i].cgroup);
return -1;
}
/* lxc_cgroup_path_get can process multiple subsystems */
ret = lxc_cgroup_path_get(&path, ctx->cgroups[i].subsystems,
&ctx->cgroups[i].cgroup[1]);
if (ret)
return -1;
ret = lxc_cgroup_attach(path, pid);
if (ret)
return -1;
}
return 0;
}
int lxc_cgroup_get(const char *name, const char *subsystem,
char *value, size_t len)
{
int fd, ret = -1;
char *nsgroup;
char path[MAXPATHLEN];
ret = lxc_cgroup_path_get(&nsgroup, name);
if (ret)
return -1;
snprintf(path, MAXPATHLEN, "%s/%s", nsgroup, subsystem);
fd = open(path, O_RDONLY);
if (fd < 0) {
ERROR("open %s : %s", path, strerror(errno));
return -1;
}
ret = read(fd, value, len);
if (ret < 0)
ERROR("read %s : %s", path, strerror(errno));
close(fd);
return ret;
}
int lxc_cgroup_nrtasks(const char *name)
{
char *nsgroup;
char path[MAXPATHLEN];
int pid, ret, count = 0;
FILE *file;
ret = lxc_cgroup_path_get(&nsgroup, name);
if (ret)
return -1;
snprintf(path, MAXPATHLEN, "%s/tasks", nsgroup);
file = fopen(path, "r");
if (!file) {
SYSERROR("fopen '%s' failed", path);
return -1;
}
while (fscanf(file, "%d", &pid) != EOF)
count++;
fclose(file);
return count;
}
static int freezer_state(const char *name)
{
char *nsgroup;
char freezer[MAXPATHLEN];
char status[MAXPATHLEN];
FILE *file;
int err;
err = lxc_cgroup_path_get(&nsgroup, "freezer", name);
if (err)
return -1;
err = snprintf(freezer, MAXPATHLEN, "%s/freezer.state", nsgroup);
if (err < 0 || err >= MAXPATHLEN)
return -1;
file = fopen(freezer, "r");
if (!file)
return -1;
err = fscanf(file, "%s", status);
fclose(file);
if (err == EOF) {
SYSERROR("failed to read %s", freezer);
return -1;
}
return lxc_str2state(status);
}
int lxc_cgroup_set(const char *name, const char *subsystem, const char *value)
{
int fd, ret;
char *nsgroup;
char path[MAXPATHLEN];
ret = lxc_cgroup_path_get(&nsgroup, name);
if (ret)
return -1;
snprintf(path, MAXPATHLEN, "%s/%s", nsgroup, subsystem);
fd = open(path, O_WRONLY);
if (fd < 0) {
ERROR("open %s : %s", path, strerror(errno));
return -1;
}
ret = write(fd, value, strlen(value));
if (ret < 0) {
ERROR("write %s : %s", path, strerror(errno));
goto out;
}
ret = 0;
out:
close(fd);
return ret;
}
int lxc_cgroup_nrtasks(const char *name)
{
char *dpath;
char path[MAXPATHLEN];
int pid, ret, count = 0;
FILE *file;
int rc;
ret = lxc_cgroup_path_get(&dpath, NULL, name);
if (ret)
return -1;
rc = snprintf(path, MAXPATHLEN, "%s/tasks", dpath);
if (rc < 0 || rc >= MAXPATHLEN) {
ERROR("pathname too long");
return -1;
}
file = fopen(path, "r");
if (!file) {
SYSERROR("fopen '%s' failed", path);
return -1;
}
while (fscanf(file, "%d", &pid) != EOF)
count++;
fclose(file);
return count;
}
int lxc_cgroup_get(const char *name, const char *filename,
char *value, size_t len)
{
int fd, ret = -1;
char *dirpath;
char path[MAXPATHLEN];
int rc;
ret = lxc_cgroup_path_get(&dirpath, filename, name);
if (ret)
return -1;
rc = snprintf(path, MAXPATHLEN, "%s/%s", dirpath, filename);
if (rc < 0 || rc >= MAXPATHLEN) {
ERROR("pathname too long");
return -1;
}
fd = open(path, O_RDONLY);
if (fd < 0) {
ERROR("open %s : %s", path, strerror(errno));
return -1;
}
ret = read(fd, value, len);
if (ret < 0)
ERROR("read %s : %s", path, strerror(errno));
close(fd);
return ret;
}
int lxc_cgroup_set(const char *name, const char *filename, const char *value)
{
int fd, ret;
char *dirpath;
char path[MAXPATHLEN];
int rc;
ret = lxc_cgroup_path_get(&dirpath, filename, name);
if (ret)
return -1;
rc = snprintf(path, MAXPATHLEN, "%s/%s", dirpath, filename);
if (rc < 0 || rc >= MAXPATHLEN) {
ERROR("pathname too long");
return -1;
}
fd = open(path, O_WRONLY);
if (fd < 0) {
ERROR("open %s : %s", path, strerror(errno));
return -1;
}
ret = write(fd, value, strlen(value));
if (ret < 0) {
ERROR("write %s : %s", path, strerror(errno));
goto out;
}
ret = 0;
out:
close(fd);
return ret;
}
int lxc_cgroup_set(const char *name, const char *filename, const char *value,
const char *lxcpath)
{
int ret;
char *dirpath;
char path[MAXPATHLEN];
ret = lxc_cgroup_path_get(&dirpath, filename, name, lxcpath);
if (ret)
return -1;
ret = snprintf(path, MAXPATHLEN, "%s/%s", dirpath, filename);
if (ret < 0 || ret >= MAXPATHLEN) {
ERROR("pathname too long");
return -1;
}
return do_cgroup_set(path, value);
}
/*
* Get value of a cgroup setting for a container.
*
* @name: name of the container
* @filename: the cgroup file to read (i.e. 'freezer.state')
* @value: a preallocated char* into which to copy the answer
* @len: the length of pre-allocated @value
* @lxcpath: the lxcpath in which the container is running (i.e.
* /var/lib/lxc)
*
* Returns < 0 on error, or the number of bytes read.
*
* If you pass in NULL value or 0 len, then you are asking for the size of the
* file.
*
* Note that we can't get the file size quickly through stat or lseek.
* Therefore if you pass in len > 0 but less than the file size, your only
* indication will be that the return value will be equal to the passed-in ret.
* We will not return the actual full file size.
*/
int lxc_cgroup_get(const char *name, const char *filename, char *value,
size_t len, const char *lxcpath)
{
int fd, ret = -1;
char *dirpath;
char path[MAXPATHLEN];
int rc;
ret = lxc_cgroup_path_get(&dirpath, filename, name, lxcpath);
if (ret)
return -1;
rc = snprintf(path, MAXPATHLEN, "%s/%s", dirpath, filename);
if (rc < 0 || rc >= MAXPATHLEN) {
ERROR("pathname too long");
return -1;
}
fd = open(path, O_RDONLY);
if (fd < 0) {
ERROR("open %s : %s", path, strerror(errno));
return -1;
}
if (!len || !value) {
char buf[100];
int count = 0;
while ((ret = read(fd, buf, 100)) > 0)
count += ret;
if (ret >= 0)
ret = count;
} else {
memset(value, 0, len);
ret = read(fd, value, len);
}
if (ret < 0)
ERROR("read %s : %s", path, strerror(errno));
close(fd);
return ret;
}
