lxc-start is not safe (and doesn't actually make sense) if the
task is nto single-threaded.
Signed-off-by: Serge Hallyn <serge.hal...@ubuntu.com>
---
src/lxc/lxccontainer.c | 37 +++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
index 05e5405..827cae0 100644
--- a/src/lxc/lxccontainer.c
+++ b/src/lxc/lxccontainer.c
@@ -506,6 +506,38 @@ static bool wait_on_daemonized_start(struct lxc_container
*c)
return lxcapi_wait(c, "RUNNING", timeout);
}
+static bool am_single_threaded(void)
+{
+ struct dirent dirent, *direntp;
+ DIR *dir;
+ int count=0;
+
+ process_lock();
+ dir = opendir("/proc/self/task");
+ process_unlock();
+ if (!dir) {
+ INFO("failed to open /proc/self/task");
+ return false;
+ }
+
+ while (!readdir_r(dir, &dirent, &direntp)) {
+ if (!direntp)
+ break;
+
+ if (!strcmp(direntp->d_name, "."))
+ continue;
+
+ if (!strcmp(direntp->d_name, ".."))
+ continue;
+ if (++count > 1)
+ break;
+ }
+ process_lock();
+ closedir(dir);
+ process_unlock();
+ return count == 1;
+}
+
/*
* I can't decide if it'd be more convenient for callers if we accept '...',
* or a null-terminated array (i.e. execl vs execv)
@@ -598,6 +630,11 @@ static bool lxcapi_start(struct lxc_container *c, int
useinit, char * const argv
open("/dev/null", O_RDWR);
open("/dev/null", O_RDWR);
setsid();
+ } else {
+ if (!am_single_threaded()) {
+ ERROR("Cannot start non-daemonized container when
threaded");
+ return false;
+ }
}
reboot:
--
1.8.3.2
------------------------------------------------------------------------------
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