[CRIU] [PATCH 2/2] cg: Add ability to dump custom cgroup properties
Pavel Emelyanov
xemul at virtuozzo.com
Thu Apr 14 04:56:41 PDT 2016
On 04/12/2016 12:40 PM, Cyrill Gorcunov wrote:
> We have some common predefined properties such as
> "cpuset.cpus" and etc gathered in @cgp_predefined
> set, but there might be situation when only predefined
> ones are not enough so add ability to specify additional
> properties via --cgroup-props option.
>
> This option takes either path to a file or plain JSON
> stream which describe the properties to dump.
>
> For example one may pass
>
> --cgroup-props "{\"controller name 1\" : [ \"property-1\", \"property-2\", ... ]}"
>
> to dump custom properties.
>
> At moment we require Jansson library to be present in the
> system to support JSON parsing of --cgroup-props. But if
> someone doesn't need custom properties lets don't force
> him to setup Jansson library for nothing, simply compile
> criu without this feature support.
>
> Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
> ---
> criu/Makefile.config | 9 ++
> criu/cgroup-props.c | 196 ++++++++++++++++++++++++++++++++++++++++++++
> criu/cr-dump.c | 6 ++
> criu/crtools.c | 5 ++
> criu/include/cgroup-props.h | 4 +
> criu/include/cr_options.h | 1 +
> scripts/feature-tests.mak | 26 ++++++
> 7 files changed, 247 insertions(+)
>
> diff --git a/criu/Makefile.config b/criu/Makefile.config
> index 326356e1e220..ce0be7e21dbf 100644
> --- a/criu/Makefile.config
> +++ b/criu/Makefile.config
> @@ -18,6 +18,11 @@ ifeq ($(call try-cc,$(FEATURE_TEST_UFFD)),y)
> export UFFD := 1
> endif
>
> +ifeq ($(call try-cc,$(FEATURE_TEST_LIBJANSSON),-ljansson),y)
> + LIBS += -ljansson
> + JANSSON := 1
> +endif
> +
> FEATURES_LIST := TCP_REPAIR STRLCPY STRLCAT PTRACE_PEEKSIGINFO \
> SETPROCTITLE_INIT MEMFD
>
> @@ -46,6 +51,10 @@ ifeq ($$(UFFD),1)
> $(Q) @echo '#define CONFIG_HAS_UFFD' >> $$@
> $(Q) @echo '' >> $$@
> endif
> +ifeq ($$(JANSSON),1)
> + $(Q) @echo '#define CONFIG_HAS_LIBJANSSON' >> $$@
> + $(Q) @echo '' >> $$@
> +endif
> ifeq ($$(piegen-y),y)
> $(Q) @echo '#define CONFIG_PIEGEN' >> $$@
> $(Q) @echo '' >> $$@
> diff --git a/criu/cgroup-props.c b/criu/cgroup-props.c
> index 2f6ed2594cb3..2b383727db8b 100644
> --- a/criu/cgroup-props.c
> +++ b/criu/cgroup-props.c
> @@ -1,9 +1,24 @@
> #include <stdio.h>
> #include <string.h>
> #include <unistd.h>
> +#include <fcntl.h>
> +
> +#include <sys/mman.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
>
> #include "compiler.h"
> #include "cgroup-props.h"
> +#include "config.h"
> +#include "xmalloc.h"
> +#include "util.h"
> +#include "list.h"
> +#include "log.h"
> +#include "bug.h"
> +
> +#ifdef CONFIG_HAS_LIBJANSSON
> +# include <jansson.h>
> +#endif
>
> #undef LOG_PREFIX
> #define LOG_PREFIX "cg-prop: "
> @@ -98,8 +113,175 @@ static const cgp_t cgp_predefined[] = {
> },
> };
>
> +typedef struct {
> + struct list_head list;
> + cgp_t cgp;
> +} cgp_list_t;
> +
> +static LIST_HEAD(cgp_list);
> +
> +static void cgp_free(cgp_list_t *p)
> +{
> + size_t i;
> +
> + if (p) {
> + for (i = 0; i < p->cgp.nr_props; i++)
> + xfree((void *)p->cgp.props[i]);
> + xfree((void *)p->cgp.name);
> + xfree((void *)p->cgp.props);
> + xfree(p);
> + }
> +}
> +
> +static int cgp_handle_option(char *arg, size_t len)
> +{
> + void *mem = MAP_FAILED;
> + int fd = -1, ret = -1;
> + struct stat st;
> +
> + /*
> + * It's either plain JSON stream, then it must
> + * start with '{', or it's path to a file to parse.
> + */
Better introduce another option to distinguish CLI props from in-file props.
> + if (arg[0] == '{') {
> + if (cgp_parse(arg, len)) {
> + pr_err("Failed to parse stream `%s'\n", arg);
> + return -1;
> + }
> + return 0;
> + }
> +
> + fd = open(arg, O_RDONLY);
> + if (fd < 0) {
> + pr_perror("Can't open file %s\n", arg);
> + goto err;
> + }
> +
> + if (fstat(fd, &st)) {
> + pr_perror("Can't stat file %s\n", arg);
> + goto err;
> + }
> +
> + mem = mmap(NULL, st.st_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_FILE, fd, 0);
> + if (mem == MAP_FAILED) {
> + pr_perror("Can't mmap file %s\n", arg);
> + goto err;
> + }
> +
> + if (cgp_parse(mem, st.st_size)) {
> + pr_err("Failed to parse file `%s'\n", arg);
> + goto err;
> + }
> +
> + ret = 0;
> +err:
> + if (mem != MAP_FAILED)
> + munmap(mem, st.st_size);
> + close_safe(&fd);
Why not just close?
> + return ret;
> +}
> +
> +int cgp_init(char *arg, size_t len)
> +{
> + if (arg && len)
> + return cgp_handle_option(arg, len);
> + return 0;
> +}
> +
> +#ifdef CONFIG_HAS_LIBJANSSON
Why only _parse is under ifndef? From my perspective the whole
_handle_option should be such.
> +int cgp_parse(char *stream, size_t len)
Should be static
> +{
> + json_t *root, *controller_obj;
> + json_error_t error;
> +
> + const char *controller;
> + int ret = -1;
> +
> + cgp_list_t *cgp_p = NULL;
> +
> + root = json_loadb(stream, len, JSON_DISABLE_EOF_CHECK, &error);
> + if (!root) {
> + pr_err("json_loadb error: %s\n", error.text);
> + goto err;
> + }
> +
> + /*
> + * The format we expect here is
> + * {
> + * "controller name 1" : [ "property-1", "property-2", ... ],
> + * "controller name 2" : [ "property-1", "property-2", ... ]
> + * }
> + */
> +
> + json_object_foreach(root, controller, controller_obj) {
> + json_t *v;
> + size_t i;
> +
> + if (!json_is_array(controller_obj)) {
> + pr_err("Expected array props for controller %s\n", controller);
> + goto err;
> + }
> +
> + if (!cgp_p) {
> + cgp_p = xzalloc(sizeof(*cgp_p));
> + if (!cgp_p)
> + goto err;
> + INIT_LIST_HEAD(&cgp_p->list);
> + }
> +
> + cgp_p->cgp.name = xstrdup(controller);
> + if (!cgp_p->cgp.name)
> + goto err;
> +
> + pr_debug("Parsing dynamic controller '%s'\n", controller);
> +
> + if (json_array_size(controller_obj) < 1) {
> + pr_err("Expected array of props for controller %s\n", controller);
> + goto err;
> + }
> +
> + cgp_p->cgp.props = xzalloc(json_array_size(controller_obj) * sizeof(cgp_p->cgp.props));
> + if (!cgp_p->cgp.props)
> + goto err;
> + cgp_p->cgp.nr_props = json_array_size(controller_obj);
> +
> + for (i = 0; i < json_array_size(controller_obj); i++) {
> + v = json_array_get(controller_obj, i);
> +
> + if (!json_is_string(v)) {
> + pr_err("Expected strings array props for controller %s\n", controller);
> + goto err;
> + }
> +
> + pr_debug("\tproperty '%s'\n", json_string_value(v));
> +
> + cgp_p->cgp.props[i] = xstrdup(json_string_value(v));
> + if (!cgp_p->cgp.props[i])
> + goto err;
> + }
> +
> + list_add(&cgp_p->list, &cgp_list);
> + cgp_p = NULL;
> + }
> + ret = 0;
> +
> +err:
> + if (root)
> + json_decref(root);
> + cgp_free(cgp_p);
> + return ret;
> +}
> +#else
> +int cgp_parse(char *stream, size_t len)
> +{
> + pr_err("No JSON parser is compiled in. Feature unsupported\n");
> + return -1;
> +}
> +#endif
> +
> const cgp_t *cgp_get_props(const char *name)
> {
> + cgp_list_t *p;
> size_t i;
>
> for (i = 0; i < ARRAY_SIZE(cgp_predefined); i++) {
> @@ -107,5 +289,19 @@ const cgp_t *cgp_get_props(const char *name)
> return &cgp_predefined[i];
> }
>
> + list_for_each_entry(p, &cgp_list, list) {
> + if (!strcmp(p->cgp.name, name))
> + return &p->cgp;
This makes it impossible to override existing built-in prop lists.
> + }
> +
> return NULL;
> }
> +
> +void cgp_fini(void)
> +{
> + cgp_list_t *p, *t;
> +
> + list_for_each_entry_safe(p, t, &cgp_list, list)
> + cgp_free(p);
> + INIT_LIST_HEAD(&cgp_list);
> +}
> diff --git a/criu/cr-dump.c b/criu/cr-dump.c
> index 5ac9fd041e4e..6fdfe72bede7 100644
> --- a/criu/cr-dump.c
> +++ b/criu/cr-dump.c
> @@ -61,6 +61,7 @@
> #include "cpu.h"
> #include "elf.h"
> #include "cgroup.h"
> +#include "cgroup-props.h"
> #include "file-lock.h"
> #include "page-xfer.h"
> #include "kerndat.h"
> @@ -1554,6 +1555,7 @@ static int cr_dump_finish(int ret)
> ret = -1;
>
> cr_plugin_fini(CR_PLUGIN_STAGE__DUMP, ret);
> + cgp_fini();
>
> if (!ret) {
> /*
> @@ -1653,6 +1655,10 @@ int cr_dump_tasks(pid_t pid)
> if (vdso_init())
> goto err;
>
> + if (cgp_init(opts.cgroup_props,
> + opts.cgroup_props ? strlen(opts.cgroup_props) : 0))
> + goto err;
> +
> if (parse_cg_info())
> goto err;
>
> diff --git a/criu/crtools.c b/criu/crtools.c
> index 5d9647ad25c8..c23a0a3ae6c1 100644
> --- a/criu/crtools.c
> +++ b/criu/crtools.c
> @@ -38,6 +38,7 @@
> #include "mount.h"
> #include "namespaces.h"
> #include "cgroup.h"
> +#include "cgroup-props.h"
> #include "cpu.h"
> #include "action-scripts.h"
> #include "irmap.h"
> @@ -323,6 +324,7 @@ int main(int argc, char *argv[], char *envp[])
> { "extra", no_argument, 0, 1077 },
> { "experimental", no_argument, 0, 1078 },
> { "all", no_argument, 0, 1079 },
> + { "cgroup-props", required_argument, 0, 1080 },
> { },
> };
>
> @@ -627,6 +629,9 @@ int main(int argc, char *argv[], char *envp[])
> opts.check_extra_features = true;
> opts.check_experimental_features = true;
> break;
> + case 1080:
> + opts.cgroup_props = optarg;
> + break;
> case 'V':
> pr_msg("Version: %s\n", CRIU_VERSION);
> if (strcmp(CRIU_GITID, "0"))
Help text required.
RPC bits are required too.
> diff --git a/criu/include/cgroup-props.h b/criu/include/cgroup-props.h
> index 1259e0cdc27f..07d5261b397f 100644
> --- a/criu/include/cgroup-props.h
> +++ b/criu/include/cgroup-props.h
> @@ -10,4 +10,8 @@ typedef struct {
> extern cgp_t cgp_global;
> extern const cgp_t *cgp_get_props(const char *name);
>
> +extern int cgp_init(char *arg, size_t len);
> +extern void cgp_fini(void);
> +extern int cgp_parse(char *stream, size_t len);
> +
> #endif /* __CR_CGROUP_PROPS_H__ */
> diff --git a/criu/include/cr_options.h b/criu/include/cr_options.h
> index b6ae3a146b8d..ff7abfec73cf 100644
> --- a/criu/include/cr_options.h
> +++ b/criu/include/cr_options.h
> @@ -97,6 +97,7 @@ struct cr_options {
> char **exec_cmd;
> unsigned int manage_cgroups;
> char *new_global_cg_root;
> + char *cgroup_props;
> struct list_head new_cgroup_roots;
> bool autodetect_ext_mounts;
> bool enable_external_sharing;
> diff --git a/scripts/feature-tests.mak b/scripts/feature-tests.mak
> index c48b52e7a7ad..55fe12c3d640 100644
> --- a/scripts/feature-tests.mak
> +++ b/scripts/feature-tests.mak
> @@ -105,3 +105,29 @@ int main(void)
> }
>
> endef
> +
> +define FEATURE_TEST_LIBJANSSON
> +
> +#include <jansson.h>
> +
> +int main(int argc, char *argv[], char *envp[])
> +{
> + json_error_t error;
> + const char *v;
> + json_t *obj;
> +
> + (void)json_loadb(v, 0, 0, &error);
> + json_object_foreach(obj, v, obj);
> + (void)json_is_array(obj);
> + (void)json_array_size(obj);
> + (void)json_array_get(obj, 0);
> + (void)json_is_string(obj);
> + (void)json_decref(obj);
> +
> + (void)error;
> + (void)v;
> + (void)obj;
> +
> + return 0;
> +}
> +endef
>
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