diff --git a/doc/lxc-attach.sgml.in b/doc/lxc-attach.sgml.in
index 36e1f70f2..a3bdb4499 100644
--- a/doc/lxc-attach.sgml.in
+++ b/doc/lxc-attach.sgml.in
@@ -54,6 +54,8 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-e-s namespaces-R
+ --keep-env
+ --clear-env-- command
@@ -173,6 +175,37 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+
+
+
+
+
+ Keep the current environment for attached programs. This is
+ the current default behaviour (as of version 0.9), but is
+ is likely to change in the future, since this may leak
+ undesirable information into the container. If you rely on
+ the environment being available for the attached program,
+ please use this option to be future-proof. In addition to
+ current environment variables, container=lxc will be set.
+
+
+
+
+
+
+
+
+
+
+ Clear the environment before attaching, so no undesired
+ environment variables leak into the container. The variable
+ container=lxc will be the only environment with which the
+ attached program starts.
+
+
+
+
diff --git a/src/lxc/attach.c b/src/lxc/attach.c
index 12adadb56..5b3ee4fc1 100644
--- a/src/lxc/attach.c
+++ b/src/lxc/attach.c
@@ -277,11 +277,26 @@ int lxc_attach_drop_privs(struct lxc_proc_context_info *ctx)
return 0;
}
-int lxc_attach_set_environment()
+int lxc_attach_set_environment(enum lxc_attach_env_policy_t policy, char** extra_env, char** extra_keep)
{
- if (clearenv()) {
- SYSERROR("failed to clear environment");
- /* don't error out though */
+ /* TODO: implement extra_env, extra_keep
+ * Rationale:
+ * - extra_env is an array of strings of the form
+ * "VAR=VALUE", which are to be set (after clearing or not,
+ * depending on the value of the policy variable)
+ * - extra_keep is an array of strings of the form
+ * "VAR", which are extra environment variables to be kept
+ * around after clearing (if that is done, otherwise, the
+ * remain anyway)
+ */
+ (void) extra_env;
+ (void) extra_keep;
+
+ if (policy == LXC_ATTACH_CLEAR_ENV) {
+ if (clearenv()) {
+ SYSERROR("failed to clear environment");
+ /* don't error out though */
+ }
}
if (putenv("container=lxc")) {
diff --git a/src/lxc/attach.h b/src/lxc/attach.h
index 404ff4c22..151445ae8 100644
--- a/src/lxc/attach.h
+++ b/src/lxc/attach.h
@@ -34,10 +34,15 @@ struct lxc_proc_context_info {
extern struct lxc_proc_context_info *lxc_proc_get_context_info(pid_t pid);
+typedef enum lxc_attach_env_policy_t {
+ LXC_ATTACH_KEEP_ENV,
+ LXC_ATTACH_CLEAR_ENV
+} lxc_attach_env_policy_t;
+
extern int lxc_attach_to_ns(pid_t other_pid, int which);
extern int lxc_attach_remount_sys_proc();
extern int lxc_attach_drop_privs(struct lxc_proc_context_info *ctx);
-extern int lxc_attach_set_environment();
+extern int lxc_attach_set_environment(enum lxc_attach_env_policy_t policy, char** extra_env, char** extra_keep);
extern char *lxc_attach_getpwshell(uid_t uid);
diff --git a/src/lxc/lxc_attach.c b/src/lxc/lxc_attach.c
index 7fd76ee21..77039fbea 100644
--- a/src/lxc/lxc_attach.c
+++ b/src/lxc/lxc_attach.c
@@ -55,6 +55,9 @@ static const struct option my_longopts[] = {
{"arch", required_argument, 0, 'a'},
{"namespaces", required_argument, 0, 's'},
{"remount-sys-proc", no_argument, 0, 'R'},
+ /* TODO: decide upon short option names */
+ {"clear-env", no_argument, 0, 500},
+ {"keep-env", no_argument, 0, 501},
LXC_COMMON_OPTIONS
};
@@ -62,6 +65,7 @@ static int elevated_privileges = 0;
static signed long new_personality = -1;
static int namespace_flags = -1;
static int remount_sys_proc = 0;
+static lxc_attach_env_policy_t env_policy = LXC_ATTACH_KEEP_ENV;
static int my_parser(struct lxc_arguments* args, int c, char* arg)
{
@@ -85,6 +89,12 @@ static int my_parser(struct lxc_arguments* args, int c, char* arg)
/* -s implies -e */
elevated_privileges = 1;
break;
+ case 500: /* clear-env */
+ env_policy = LXC_ATTACH_CLEAR_ENV;
+ break;
+ case 501: /* keep-env */
+ env_policy = LXC_ATTACH_KEEP_ENV;
+ break;
}
return 0;
@@ -116,7 +126,15 @@ Options :\n\
Remount /sys and /proc if not attaching to the\n\
mount namespace when using -s in order to properly\n\
reflect the correct namespace context. See the\n\
- lxc-attach(1) manual page for details.\n",
+ lxc-attach(1) manual page for details.\n\
+ --clear-env\n\
+ Clear all environment variables before attaching.\n\
+ The attached shell/program will start with only\n\
+ container=lxc set.\n\
+ --keep-env\n\
+ Keep all current enivornment variables. This\n\
+ is the current default behaviour, but is likely to\n\
+ change in the future.\n",
.options = my_longopts,
.parser = my_parser,
.checker = NULL,
@@ -411,7 +429,7 @@ int main(int argc, char *argv[])
return -1;
}
- if (lxc_attach_set_environment()) {
+ if (lxc_attach_set_environment(env_policy, NULL, NULL)) {
ERROR("could not set environment");
return -1;
}