On Fri, Jan 27, 2017 at 12:26 AM, Justin Cinkelj <justin.cink...@xlab.si>
wrote:
> The thread ID of thread running new app main() function is returned.
>
> Signed-off-by: Justin Cinkelj <justin.cink...@xlab.si>
> ---
> core/app.cc | 12 ++++++++++--
> include/osv/app.hh | 7 ++++++-
> 2 files changed, 16 insertions(+), 3 deletions(-)
>
> diff --git a/core/app.cc b/core/app.cc
> index ad3145f..6ea5d6e 100644
> --- a/core/app.cc
> +++ b/core/app.cc
> @@ -133,8 +133,12 @@ shared_app_t application::run(const std::string&
> command,
> return app;
> }
>
> -void run(const std::vector<std::string>& args) {
> - application::run(args);
> +void run(const std::vector<std::string>& args, pid_t *pid) {
> + auto app = application::run(args);
> + if (pid) {
> + *pid = app->get_main_thread_id();
> + assert((*pid) != 0);
> + }
>
I think this has the same bug we already solved in osv_execve() - when
application::run returns, if I understand correctly, the thread may not be
actually running, so its id is not yet set.
I guess we can solve this like we did for osv_execve() (i.e., creating a
new thread first, and then running the new application in the current
thread) but I rather not go into this mess again :-(
How about the idea I raised in another email to keep a list of
osv::application pointers - instead of "thread ids" - in the httpserver
(httpserver can assign numeric ids to those if it wishes)?
> }
>
> shared_app_t application::run_and_join(const std::string& command,
> @@ -419,6 +423,10 @@ std::string application::get_command()
> return _command;
> }
>
> +pid_t application::get_main_thread_id() {
> + return pthread_gettid_np(_thread);
> +}
> +
> // For simplicity, we will not reuse bits in the bitmap, since no
> destructor is
> // assigned to the program. In that case, a simple counter would do. But
> coding
> // this way is easy, and make this future extension simple.
> diff --git a/include/osv/app.hh b/include/osv/app.hh
> index 6fa503a..90bc7ce 100644
> --- a/include/osv/app.hh
> +++ b/include/osv/app.hh
> @@ -176,6 +176,11 @@ public:
> */
> std::string get_command();
>
> + /**
> + * Returns thread_id/PID of thread running app main() function.
> + */
> + pid_t get_main_thread_id();
> +
> std::shared_ptr<application_runtime> runtime() const { return
> _runtime; }
> std::shared_ptr<elf::object> lib() const { return _lib; }
>
> @@ -238,7 +243,7 @@ namespace osv {
> * Creates a new app
> * args Arguments passed to the program's main() function.
> */
> -void run(const std::vector<std::string>& args);
> +void run(const std::vector<std::string>& args, pid_t *pid=nullptr);
>
By the way, I already committed a patch to rename this function
run_background.
If we adopt the idea I raised above, this run_background() function can
return a shared_app_t instead of trying to return a thread id (because at
the point of return, the app already exists but the thread does not).
Nadav.
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