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cgroup1: switch to option-by-option parsing 

[dhowells should be the author - it's carved out of his patch]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2019-01-17 00:15:11 -05:00
parent f5dfb5315d
commit 8d2451f499
3 changed files with 116 additions and 97 deletions
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3
kernel/cgroup/cgroup-internal.h
View File

@ -257,14 +257,15 @@ extern const struct proc_ns_operations cgroupns_operations;
*/
extern struct cftype cgroup1_base_files[];
extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops;
extern const struct fs_parameter_description cgroup1_fs_parameters;
int proc_cgroupstats_show(struct seq_file *m, void *v);
bool cgroup1_ssid_disabled(int ssid);
void cgroup1_pidlist_destroy_all(struct cgroup *cgrp);
void cgroup1_release_agent(struct work_struct *work);
void cgroup1_check_for_release(struct cgroup *cgrp);
int cgroup1_parse_param(struct fs_context *fc, struct fs_parameter *param);
int cgroup1_get_tree(struct fs_context *fc);
int parse_cgroup1_options(char *data, struct cgroup_fs_context *ctx);
int cgroup1_reconfigure(struct fs_context *ctx);
#endif /* __CGROUP_INTERNAL_H */

190
kernel/cgroup/cgroup-v1.c
View File

@ -13,9 +13,12 @@
#include <linux/delayacct.h>
#include <linux/pid_namespace.h>
#include <linux/cgroupstats.h>
#include <linux/fs_parser.h>
#include <trace/events/cgroup.h>
#define cg_invalf(fc, fmt, ...) ({ pr_err(fmt, ## __VA_ARGS__); -EINVAL; })
/*
* pidlists linger the following amount before being destroyed. The goal
* is avoiding frequent destruction in the middle of consecutive read calls
@ -906,94 +909,117 @@ static int cgroup1_show_options(struct seq_file *seq, struct kernfs_root *kf_roo
return 0;
}
int parse_cgroup1_options(char *data, struct cgroup_fs_context *ctx)
enum cgroup1_param {
Opt_all,
Opt_clone_children,
Opt_cpuset_v2_mode,
Opt_name,
Opt_none,
Opt_noprefix,
Opt_release_agent,
Opt_xattr,
};
static const struct fs_parameter_spec cgroup1_param_specs[] = {
fsparam_flag ("all", Opt_all),
fsparam_flag ("clone_children", Opt_clone_children),
fsparam_flag ("cpuset_v2_mode", Opt_cpuset_v2_mode),
fsparam_string("name", Opt_name),
fsparam_flag ("none", Opt_none),
fsparam_flag ("noprefix", Opt_noprefix),
fsparam_string("release_agent", Opt_release_agent),
fsparam_flag ("xattr", Opt_xattr),
{}
};
const struct fs_parameter_description cgroup1_fs_parameters = {
.name = "cgroup1",
.specs = cgroup1_param_specs,
};
int cgroup1_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
char *token, *o = data;
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
struct cgroup_subsys *ss;
int i;
struct fs_parse_result result;
int opt, i;
while ((token = strsep(&o, ",")) != NULL) {
if (!*token)
return -EINVAL;
if (!strcmp(token, "none")) {
/* Explicitly have no subsystems */
ctx->none = true;
continue;
opt = fs_parse(fc, &cgroup1_fs_parameters, param, &result);
if (opt == -ENOPARAM) {
if (strcmp(param->key, "source") == 0) {
fc->source = param->string;
param->string = NULL;
return 0;
}
if (!strcmp(token, "all")) {
ctx->all_ss = true;
continue;
}
if (!strcmp(token, "noprefix")) {
ctx->flags |= CGRP_ROOT_NOPREFIX;
continue;
}
if (!strcmp(token, "clone_children")) {
ctx->cpuset_clone_children = true;
continue;
}
if (!strcmp(token, "cpuset_v2_mode")) {
ctx->flags |= CGRP_ROOT_CPUSET_V2_MODE;
continue;
}
if (!strcmp(token, "xattr")) {
ctx->flags |= CGRP_ROOT_XATTR;
continue;
}
if (!strncmp(token, "release_agent=", 14)) {
/* Specifying two release agents is forbidden */
if (ctx->release_agent)
return -EINVAL;
ctx->release_agent =
kstrndup(token + 14, PATH_MAX - 1, GFP_KERNEL);
if (!ctx->release_agent)
return -ENOMEM;
continue;
}
if (!strncmp(token, "name=", 5)) {
const char *name = token + 5;
/* blocked by boot param? */
if (cgroup_no_v1_named)
return -ENOENT;
/* Can't specify an empty name */
if (!strlen(name))
return -EINVAL;
/* Must match [\w.-]+ */
for (i = 0; i < strlen(name); i++) {
char c = name[i];
if (isalnum(c))
continue;
if ((c == '.') || (c == '-') || (c == '_'))
continue;
return -EINVAL;
}
/* Specifying two names is forbidden */
if (ctx->name)
return -EINVAL;
ctx->name = kstrndup(name,
MAX_CGROUP_ROOT_NAMELEN - 1,
GFP_KERNEL);
if (!ctx->name)
return -ENOMEM;
continue;
}
for_each_subsys(ss, i) {
if (strcmp(token, ss->legacy_name))
if (strcmp(param->key, ss->legacy_name))
continue;
ctx->subsys_mask |= (1 << i);
break;
return 0;
}
if (i == CGROUP_SUBSYS_COUNT)
return cg_invalf(fc, "cgroup1: Unknown subsys name '%s'", param->key);
}
if (opt < 0)
return opt;
switch (opt) {
case Opt_none:
/* Explicitly have no subsystems */
ctx->none = true;
break;
case Opt_all:
ctx->all_ss = true;
break;
case Opt_noprefix:
ctx->flags |= CGRP_ROOT_NOPREFIX;
break;
case Opt_clone_children:
ctx->cpuset_clone_children = true;
break;
case Opt_cpuset_v2_mode:
ctx->flags |= CGRP_ROOT_CPUSET_V2_MODE;
break;
case Opt_xattr:
ctx->flags |= CGRP_ROOT_XATTR;
break;
case Opt_release_agent:
/* Specifying two release agents is forbidden */
if (ctx->release_agent)
return cg_invalf(fc, "cgroup1: release_agent respecified");
ctx->release_agent = param->string;
param->string = NULL;
break;
case Opt_name:
/* blocked by boot param? */
if (cgroup_no_v1_named)
return -ENOENT;
/* Can't specify an empty name */
if (!param->size)
return cg_invalf(fc, "cgroup1: Empty name");
if (param->size > MAX_CGROUP_ROOT_NAMELEN - 1)
return cg_invalf(fc, "cgroup1: Name too long");
/* Must match [\w.-]+ */
for (i = 0; i < param->size; i++) {
char c = param->string[i];
if (isalnum(c))
continue;
if ((c == '.') || (c == '-') || (c == '_'))
continue;
return cg_invalf(fc, "cgroup1: Invalid name");
}
/* Specifying two names is forbidden */
if (ctx->name)
return cg_invalf(fc, "cgroup1: name respecified");
ctx->name = param->string;
param->string = NULL;
break;
}
return 0;
}
static int check_cgroupfs_options(struct cgroup_fs_context *ctx)
static int check_cgroupfs_options(struct fs_context *fc)
{
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
u16 mask = U16_MAX;
u16 enabled = 0;
struct cgroup_subsys *ss;
@ -1018,7 +1044,7 @@ static int check_cgroupfs_options(struct cgroup_fs_context *ctx)
if (ctx->all_ss) {
/* Mutually exclusive option 'all' + subsystem name */
if (ctx->subsys_mask)
return -EINVAL;
return cg_invalf(fc, "cgroup1: subsys name conflicts with all");
/* 'all' => select all the subsystems */
ctx->subsys_mask = enabled;
}
@ -1028,7 +1054,7 @@ static int check_cgroupfs_options(struct cgroup_fs_context *ctx)
* empty hierarchies must have a name).
*/
if (!ctx->subsys_mask && !ctx->name)
return -EINVAL;
return cg_invalf(fc, "cgroup1: Need name or subsystem set");
/*
* Option noprefix was introduced just for backward compatibility
@ -1036,11 +1062,11 @@ static int check_cgroupfs_options(struct cgroup_fs_context *ctx)
* the cpuset subsystem.
*/
if ((ctx->flags & CGRP_ROOT_NOPREFIX) && (ctx->subsys_mask & mask))
return -EINVAL;
return cg_invalf(fc, "cgroup1: noprefix used incorrectly");
/* Can't specify "none" and some subsystems */
if (ctx->subsys_mask && ctx->none)
return -EINVAL;
return cg_invalf(fc, "cgroup1: none used incorrectly");
return 0;
}
@ -1056,7 +1082,7 @@ int cgroup1_reconfigure(struct fs_context *fc)
cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
/* See what subsystems are wanted */
ret = check_cgroupfs_options(ctx);
ret = check_cgroupfs_options(fc);
if (ret)
goto out_unlock;
@ -1070,7 +1096,7 @@ int cgroup1_reconfigure(struct fs_context *fc)
/* Don't allow flags or name to change at remount */
if ((ctx->flags ^ root->flags) ||
(ctx->name && strcmp(ctx->name, root->name))) {
pr_err("option or name mismatch, new: 0x%x \"%s\", old: 0x%x \"%s\"\n",
cg_invalf(fc, "option or name mismatch, new: 0x%x \"%s\", old: 0x%x \"%s\"",
ctx->flags, ctx->name ?: "", root->flags, root->name);
ret = -EINVAL;
goto out_unlock;
@ -1125,7 +1151,7 @@ int cgroup1_get_tree(struct fs_context *fc)
cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
/* First find the desired set of subsystems */
ret = check_cgroupfs_options(ctx);
ret = check_cgroupfs_options(fc);
if (ret)
goto out_unlock;
@ -1192,7 +1218,7 @@ int cgroup1_get_tree(struct fs_context *fc)
* can't create new one without subsys specification.
*/
if (!ctx->subsys_mask && !ctx->none) {
ret = -EINVAL;
ret = cg_invalf(fc, "cgroup1: No subsys list or none specified");
goto out_unlock;
}

20
kernel/cgroup/cgroup.c
View File

@ -2083,15 +2083,6 @@ static int cgroup_parse_monolithic(struct fs_context *fc, void *data)
return parse_cgroup_root_flags(data, &ctx->flags);
}
static int cgroup1_parse_monolithic(struct fs_context *fc, void *data)
{
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
if (data)
security_sb_eat_lsm_opts(data, &fc->security);
return parse_cgroup1_options(data, ctx);
}
static int cgroup_get_tree(struct fs_context *fc)
{
struct cgroup_namespace *ns = current->nsproxy->cgroup_ns;
@ -2124,7 +2115,7 @@ static const struct fs_context_operations cgroup_fs_context_ops = {
static const struct fs_context_operations cgroup1_fs_context_ops = {
.free = cgroup_fs_context_free,
.parse_monolithic = cgroup1_parse_monolithic,
.parse_param = cgroup1_parse_param,
.get_tree = cgroup1_get_tree,
.reconfigure = cgroup1_reconfigure,
};
@ -2175,10 +2166,11 @@ static void cgroup_kill_sb(struct super_block *sb)
}
struct file_system_type cgroup_fs_type = {
.name = "cgroup",
.init_fs_context = cgroup_init_fs_context,
.kill_sb = cgroup_kill_sb,
.fs_flags = FS_USERNS_MOUNT,
.name = "cgroup",
.init_fs_context = cgroup_init_fs_context,
.parameters = &cgroup1_fs_parameters,
.kill_sb = cgroup_kill_sb,
.fs_flags = FS_USERNS_MOUNT,
};
static struct file_system_type cgroup2_fs_type = {