[lxc-devel] [PATCH] c/r: tell CRIU about all external mounts in the config
Serge Hallyn
serge.hallyn at ubuntu.com
Fri Apr 3 21:41:03 UTC 2015
Quoting Tycho Andersen (tycho.andersen at canonical.com):
> Signed-off-by: Tycho Andersen <tycho.andersen at canonical.com>
> ---
> src/lxc/conf.c | 18 +++++++++++---
> src/lxc/conf.h | 2 ++
> src/lxc/list.h | 11 +++++++++
> src/lxc/lxccontainer.c | 67 +++++++++++++++++++++++++++++++++++++++++++-------
> 4 files changed, 85 insertions(+), 13 deletions(-)
>
> diff --git a/src/lxc/conf.c b/src/lxc/conf.c
> index 2868708..f9c7e37 100644
> --- a/src/lxc/conf.c
> +++ b/src/lxc/conf.c
> @@ -2040,18 +2040,16 @@ static int setup_mount(const struct lxc_rootfs *rootfs, const char *fstab,
> return ret;
> }
>
> -static int setup_mount_entries(const struct lxc_rootfs *rootfs, struct lxc_list *mount,
> - const char *lxc_name)
> +FILE *write_mount_file(struct lxc_list *mount)
> {
> FILE *file;
> struct lxc_list *iterator;
> char *mount_entry;
> - int ret;
>
> file = tmpfile();
> if (!file) {
> ERROR("tmpfile error: %m");
> - return -1;
> + return NULL;
> }
>
> lxc_list_for_each(iterator, mount) {
> @@ -2060,6 +2058,18 @@ static int setup_mount_entries(const struct lxc_rootfs *rootfs, struct lxc_list
> }
>
> rewind(file);
> + return file;
> +}
> +
> +static int setup_mount_entries(const struct lxc_rootfs *rootfs, struct lxc_list *mount,
> + const char *lxc_name)
> +{
> + FILE *file;
> + int ret;
> +
> + file = write_mount_file(mount);
> + if (!file)
> + return -1;
>
> ret = mount_file_entries(rootfs, file, lxc_name);
>
> diff --git a/src/lxc/conf.h b/src/lxc/conf.h
> index 334ea70..4b66045 100644
> --- a/src/lxc/conf.h
> +++ b/src/lxc/conf.h
> @@ -25,6 +25,7 @@
>
> #include "config.h"
>
> +#include <stdio.h>
> #include <netinet/in.h>
> #include <net/if.h>
> #include <sys/param.h>
> @@ -422,4 +423,5 @@ extern int parse_mntopts(const char *mntopts, unsigned long *mntflags,
> extern void tmp_proc_unmount(struct lxc_conf *lxc_conf);
> void remount_all_slave(void);
> extern void suggest_default_idmap(void);
> +FILE *write_mount_file(struct lxc_list *mount);
> #endif
> diff --git a/src/lxc/list.h b/src/lxc/list.h
> index 0882da0..f16af54 100644
> --- a/src/lxc/list.h
> +++ b/src/lxc/list.h
> @@ -99,4 +99,15 @@ static inline void lxc_list_del(struct lxc_list *list)
> prev->next = next;
> }
>
> +static inline int lxc_list_len(struct lxc_list *list)
> +{
> + int i = 0;
> + struct lxc_list *iter;
> + lxc_list_for_each(iter, list) {
> + i++;
> + }
> +
> + return i;
> +}
> +
> #endif
> diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
> index d84543f..7e50372 100644
> --- a/src/lxc/lxccontainer.c
> +++ b/src/lxc/lxccontainer.c
> @@ -35,6 +35,8 @@
> #include <libgen.h>
> #include <stdint.h>
> #include <grp.h>
> +#include <stdio.h>
> +#include <mntent.h>
> #include <sys/syscall.h>
>
> #include <lxc/lxccontainer.h>
> @@ -3513,11 +3515,15 @@ struct criu_opts {
>
> static void exec_criu(struct criu_opts *opts)
> {
> - char **argv, log[PATH_MAX], buf[257];
> + char **argv, log[PATH_MAX];
> int static_args = 14, argc = 0, i, ret;
> int netnr = 0;
> struct lxc_list *it;
>
> + struct mntent mntent;
> + char buf[4096];
> + FILE *mnts = NULL;
> +
> /* The command line always looks like:
> * criu $(action) --tcp-established --file-locks --link-remap --force-irmap \
> * --manage-cgroups action-script foo.sh -D $(directory) \
> @@ -3592,6 +3598,21 @@ static void exec_criu(struct criu_opts *opts)
> if (opts->verbose)
> DECLARE_ARG("-vvvvvv");
>
> +#define RESIZE_ARGS(additional) \
This seems to want to be reused, however it doesn't bump argc,
so if it is used twice in a row it wont' have the desired effect.
> + do { \
> + void *m; \
> + if (additional < 0) { \
> + ERROR("resizing by negative amount"); \
> + goto err; \
> + } else if (additional == 0) \
> + continue; \
> + \
> + m = realloc(argv, (argc + additional + 1) * sizeof(*argv)); \
> + if (!m) \
> + goto err; \
> + argv = m; \
> + } while (0)
> +
> if (strcmp(opts->action, "dump") == 0) {
> char pid[32];
>
> @@ -3623,9 +3644,10 @@ static void exec_criu(struct criu_opts *opts)
> DECLARE_ARG("--cgroup-root");
> DECLARE_ARG(opts->cgroup_path);
>
> + RESIZE_ARGS(lxc_list_len(&opts->c->lxc_conf->network) * 2);
> +
> lxc_list_for_each(it, &opts->c->lxc_conf->network) {
> char eth[128], *veth;
> - void *m;
> struct lxc_netdev *n = it->elem;
>
> if (n->name) {
> @@ -3641,18 +3663,42 @@ static void exec_criu(struct criu_opts *opts)
> if (ret < 0 || ret >= sizeof(buf))
> goto err;
>
> - /* final NULL and --veth-pair eth0=vethASDF */
> - m = realloc(argv, (argc + 1 + 2) * sizeof(*argv));
> - if (!m)
> - goto err;
> - argv = m;
> -
> DECLARE_ARG("--veth-pair");
> DECLARE_ARG(buf);
> - argv[argc] = NULL;
> + }
> + }
> +
> + // CRIU wants to know about any external bind mounts the
> + // container has.
> + mnts = write_mount_file(&opts->c->lxc_conf->mount_list);
> + if (!mnts)
> + goto err;
> +
> + RESIZE_ARGS(lxc_list_len(&opts->c->lxc_conf->mount_list) * 2);
> +
> + while (getmntent_r(mnts, &mntent, buf, sizeof(buf))) {
> + char arg[2048], *key, *val;
> + int ret;
>
> + if (strcmp(opts->action, "dump") == 0) {
> + key = mntent.mnt_fsname;
> + val = mntent.mnt_dir;
> + } else {
> + key = mntent.mnt_dir;
> + val = mntent.mnt_fsname;
> }
> +
> + ret = snprintf(arg, sizeof(arg), "%s:%s", key, val);
> + if (ret < 0 || ret >= sizeof(arg)) {
> + goto err;
> + }
> +
> + DECLARE_ARG("--ext-mount-map");
> + DECLARE_ARG(arg);
> }
> + fclose(mnts);
> +
> + argv[argc] = NULL;
>
> netnr = 0;
> lxc_list_for_each(it, &opts->c->lxc_conf->network) {
> @@ -3688,8 +3734,11 @@ static void exec_criu(struct criu_opts *opts)
> }
>
> #undef DECLARE_ARG
> +#undef RESIZE_ARGS
> execv(argv[0], argv);
> err:
> + if (mnts)
> + fclose(mnts);
> for (i = 0; argv[i]; i++)
> free(argv[i]);
> free(argv);
> --
> 2.1.0
>
> _______________________________________________
> lxc-devel mailing list
> lxc-devel at lists.linuxcontainers.org
> http://lists.linuxcontainers.org/listinfo/lxc-devel
More information about the lxc-devel
mailing list