path: root/vm_core.h
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authornormal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2018-06-27 03:14:30 (GMT)
committernormal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2018-06-27 03:14:30 (GMT)
commit054a412d540e7ed2de63d68da753f585ea6616c3 (patch)
tree550ff5e80d4735d7a5c3f05605a180cfcba526b2 /vm_core.h
parente3e22c551d24829e0f9ce84afd3653867582034b (diff)
hijack SIGCHLD handler for internal use
Use a global SIGCHLD handler to guard all callers of rb_waitpid. To work safely with multi-threaded programs, we introduce a VM-wide waitpid_lock to be acquired BEFORE fork/vfork spawns the process. This is to be combined with the new ruby_waitpid_locked function used by mjit.c in a non-Ruby thread. Ruby-level SIGCHLD handlers registered with Signal.trap(:CHLD) continues to work as before and there should be no regressions in any existing use cases. Splitting the wait queues for PID > 0 and groups (PID <= 0) ensures we favor PID > 0 callers. The disabling of SIGCHLD in rb_f_system is longer necessary, as we use deferred signal handling and no longer make ANY blocking waitpid syscalls in other threads which could "beat" the waitpid call made by rb_f_system. We prevent SIGCHLD from firing in normal Ruby Threads and only enable it in the timer-thread, to prevent spurious wakeups from in test/-ext-/gvl/test_last_thread.rb with MJIT enabled. I've tried to guard as much of the code for RUBY_SIGCHLD==0 using C "if" statements rather than CPP "#if" so to reduce the likelyhood of portability problems as the compiler will see more code. We also work to suppress false-positives from Process.wait(-1, Process::WNOHANG) to quiets warnings from spec/ruby/core/process/wait2_spec.rb with MJIT enabled. Lastly, we must implement rb_grantpt for ext/pty. We need a MJIT-compatible way of supporting grantpt(3) which may spawn the `pt_chown' binary and call waitpid(2) on it. [ruby-core:87605] [Ruby trunk Bug#14867] git-svn-id: svn+ssh:// b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'vm_core.h')
1 files changed, 13 insertions, 0 deletions
diff --git a/vm_core.h b/vm_core.h
index ee15119..bdbe872 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -92,6 +92,14 @@
+#if defined(SIGCLD)
+#elif defined(SIGCHLD)
+# define RUBY_SIGCHLD (0)
#include <stdarg.h>
#define va_init_list(a,b) va_start((a),(b))
@@ -553,6 +561,9 @@ typedef struct rb_vm_struct {
rb_serial_t fork_gen;
+ rb_nativethread_lock_t waitpid_lock;
+ struct list_head waiting_pids; /* PID > 0: <=> struct waitpid_state */
+ struct list_head waiting_grps; /* PID <= 0: <=> struct waitpid_state */
struct list_head waiting_fds; /* <=> struct waiting_fd */
struct list_head living_threads;
VALUE thgroup_default;
@@ -1561,6 +1572,8 @@ static inline void
rb_vm_living_threads_init(rb_vm_t *vm)
+ list_head_init(&vm->waiting_pids);
+ list_head_init(&vm->waiting_grps);
vm->living_thread_num = 0;