[lxc-devel] [PATCH 4/8] Add attach support to container C API
Serge Hallyn
serge.hallyn at ubuntu.com
Wed Aug 14 20:33:42 UTC 2013
Quoting Christian Seiler (christian at iwakd.de):
> Signed-off-by: Christian Seiler <christian at iwakd.de>
Acked-by: Serge E. Hallyn <serge.hallyn at ubuntu.com>
> ---
> src/lxc/lxccontainer.c | 124 ++++++++++++++++++++++++++++--------------------
> src/lxc/lxccontainer.h | 8 +++-
> 2 files changed, 80 insertions(+), 52 deletions(-)
>
> diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
> index 3affe22..1c77b63 100644
> --- a/src/lxc/lxccontainer.c
> +++ b/src/lxc/lxccontainer.c
> @@ -18,6 +18,7 @@
> */
>
> #define _GNU_SOURCE
> +#include <stdarg.h>
> #include <pthread.h>
> #include <unistd.h>
> #include <sys/types.h>
> @@ -38,6 +39,7 @@
> #include "log.h"
> #include "bdev.h"
> #include "utils.h"
> +#include "attach.h"
> #include <lxc/utils.h>
> #include <lxc/monitor.h>
> #include <sched.h>
> @@ -583,51 +585,30 @@ reboot:
> static bool lxcapi_startl(struct lxc_container *c, int useinit, ...)
> {
> va_list ap;
> - char **inargs = NULL, **temp;
> - int n_inargs = 0;
> + char **inargs = NULL;
> bool bret = false;
>
> /* container exists */
> if (!c)
> return false;
>
> - /* build array of arguments if any */
> va_start(ap, useinit);
> - while (1) {
> - char *arg;
> - arg = va_arg(ap, char *);
> - if (!arg)
> - break;
> - n_inargs++;
> - temp = realloc(inargs, n_inargs * sizeof(*inargs));
> - if (!temp) {
> - va_end(ap);
> - goto out;
> - }
> - inargs = temp;
> - inargs[n_inargs - 1] = strdup(arg); // not sure if it's safe not to copy
> - }
> + inargs = lxc_va_arg_list_to_argv(ap, 0, 1);
> va_end(ap);
>
> - /* add trailing NULL */
> - if (n_inargs) {
> - n_inargs++;
> - temp = realloc(inargs, n_inargs * sizeof(*inargs));
> - if (!temp)
> - goto out;
> - inargs = temp;
> - inargs[n_inargs - 1] = NULL;
> + if (!inargs) {
> + ERROR("Memory allocation error.");
> + goto out;
> }
>
> - bret = lxcapi_start(c, useinit, inargs);
> + /* pass NULL if no arguments were supplied */
> + bret = lxcapi_start(c, useinit, *inargs ? inargs : NULL);
>
> out:
> if (inargs) {
> - int i;
> - for (i = 0; i < n_inargs; i++) {
> - if (inargs[i])
> - free(inargs[i]);
> - }
> + char *arg;
> + for (arg = *inargs; arg; arg++)
> + free(arg);
> free(inargs);
> }
>
> @@ -1133,9 +1114,8 @@ static bool lxcapi_createl(struct lxc_container *c, const char *t,
> const char *bdevtype, struct bdev_specs *specs, int flags, ...)
> {
> bool bret = false;
> - char **args = NULL, **temp;
> + char **args = NULL;
> va_list ap;
> - int nargs = 0;
>
> if (!c)
> return false;
> @@ -1145,29 +1125,17 @@ static bool lxcapi_createl(struct lxc_container *c, const char *t,
> * need to get a copy of the arguments.
> */
> va_start(ap, flags);
> - while (1) {
> - char *arg;
> - arg = va_arg(ap, char *);
> - if (!arg)
> - break;
> - nargs++;
> - temp = realloc(args, (nargs+1) * sizeof(*args));
> - if (!temp) {
> - va_end(ap);
> - goto out;
> - }
> - args = temp;
> - args[nargs - 1] = arg;
> - }
> + args = lxc_va_arg_list_to_argv(ap, 0, 0);
> va_end(ap);
> - if (args)
> - args[nargs] = NULL;
> + if (!args) {
> + ERROR("Memory allocation error.");
> + goto out;
> + }
>
> bret = c->create(c, t, bdevtype, specs, flags, args);
>
> out:
> - if (args)
> - free(args);
> + free(args);
> return bret;
> }
>
> @@ -2000,6 +1968,57 @@ out:
> return NULL;
> }
>
> +static int lxcapi_attach(struct lxc_container *c, lxc_attach_exec_t exec_function, void *exec_payload, lxc_attach_options_t *options, pid_t *attached_process)
> +{
> + if (!c)
> + return -1;
> +
> + return lxc_attach(c->name, c->config_path, exec_function, exec_payload, options, attached_process);
> +}
> +
> +static int lxcapi_attach_run_wait(struct lxc_container *c, lxc_attach_options_t *options, const char *program, const char * const argv[])
> +{
> + lxc_attach_command_t command;
> + pid_t pid;
> + int r;
> +
> + if (!c)
> + return -1;
> +
> + command.program = (char*)program;
> + command.argv = (char**)argv;
> + r = lxc_attach(c->name, c->config_path, lxc_attach_run_command, &command, options, &pid);
> + if (r < 0) {
> + ERROR("ups");
> + return r;
> + }
> + return lxc_wait_for_pid_status(pid);
> +}
> +
> +static int lxcapi_attach_run_waitl(struct lxc_container *c, lxc_attach_options_t *options, const char *program, const char *arg, ...)
> +{
> + va_list ap;
> + const char **argv;
> + int ret;
> +
> + if (!c)
> + return -1;
> +
> + va_start(ap, arg);
> + argv = lxc_va_arg_list_to_argv_const(ap, 1);
> + va_end(ap);
> +
> + if (!argv) {
> + ERROR("Memory allocation error.");
> + return -1;
> + }
> + argv[0] = arg;
> +
> + ret = lxcapi_attach_run_wait(c, options, program, (const char * const *)argv);
> + free((void*)argv);
> + return ret;
> +}
> +
> struct lxc_container *lxc_container_new(const char *name, const char *configpath)
> {
> struct lxc_container *c;
> @@ -2086,6 +2105,9 @@ struct lxc_container *lxc_container_new(const char *name, const char *configpath
> c->set_config_path = lxcapi_set_config_path;
> c->clone = lxcapi_clone;
> c->get_ips = lxcapi_get_ips;
> + c->attach = lxcapi_attach;
> + c->attach_run_wait = lxcapi_attach_run_wait;
> + c->attach_run_waitl = lxcapi_attach_run_waitl;
>
> /* we'll allow the caller to update these later */
> if (lxc_log_init(NULL, "none", NULL, "lxc_container", 0, c->config_path)) {
> diff --git a/src/lxc/lxccontainer.h b/src/lxc/lxccontainer.h
> index 3399c7f..e0c465c 100644
> --- a/src/lxc/lxccontainer.h
> +++ b/src/lxc/lxccontainer.h
> @@ -1,6 +1,7 @@
> #ifndef __LXC_CONTAINER_H
> #define __LXC_CONTAINER_H
> #include "lxclock.h"
> +#include "attach_options.h"
> #include <stdlib.h>
> #include <malloc.h>
>
> @@ -150,12 +151,17 @@ struct lxc_container {
> int (*console)(struct lxc_container *c, int ttynum,
> int stdinfd, int stdoutfd, int stderrfd, int escape);
>
> + /* create subprocess and attach it to the container, run exec_function inside */
> + int (*attach)(struct lxc_container *c, lxc_attach_exec_t exec_function, void *exec_payload, lxc_attach_options_t *options, pid_t *attached_process);
> +
> + /* run program in container, wait for it to exit */
> + int (*attach_run_wait)(struct lxc_container *c, lxc_attach_options_t *options, const char *program, const char * const argv[]);
> + int (*attach_run_waitl)(struct lxc_container *c, lxc_attach_options_t *options, const char *program, const char *arg, ...);
> #if 0
> bool (*commit_cgroups)(struct lxc_container *c);
> bool (*reread_cgroups)(struct lxc_container *c);
> // question with clone: how do we handle non-standard config file in orig?
> struct lxc_container (*clone)(struct container *c);
> - int (*ns_attach)(struct lxc_container *c, int ns_mask);
> // we'll need some plumbing to support lxc-console
> #endif
> };
> --
> 1.7.10.4
>
>
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