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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 /ext/pty
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://ci.ruby-lang.org/ruby/trunk@63758 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'ext/pty')
-rw-r--r--ext/pty/pty.c22
1 files changed, 4 insertions, 18 deletions
diff --git a/ext/pty/pty.c b/ext/pty/pty.c
index b3c7535..1ac8906 100644
--- a/ext/pty/pty.c
+++ b/ext/pty/pty.c
@@ -246,19 +246,13 @@ get_device_once(int *master, int *slave, char SlaveName[DEVICELEN], int nomesg,
/* Unix98 PTY */
int masterfd = -1, slavefd = -1;
char *slavedevice;
- struct sigaction dfl, old;
-
- dfl.sa_handler = SIG_DFL;
- dfl.sa_flags = 0;
- sigemptyset(&dfl.sa_mask);
#if defined(__sun) || (defined(__FreeBSD__) && __FreeBSD_version < 902000)
/* workaround for Solaris 10: grantpt() doesn't work if FD_CLOEXEC is set. [ruby-dev:44688] */
/* FreeBSD 9.2 or later supports O_CLOEXEC
* http://www.freebsd.org/cgi/query-pr.cgi?pr=162374 */
if ((masterfd = posix_openpt(O_RDWR|O_NOCTTY)) == -1) goto error;
- if (sigaction(SIGCHLD, &dfl, &old) == -1) goto error;
- if (grantpt(masterfd) == -1) goto grantpt_error;
+ if (rb_grantpt(masterfd) == -1) goto error;
rb_fd_fix_cloexec(masterfd);
#else
{
@@ -272,10 +266,8 @@ get_device_once(int *master, int *slave, char SlaveName[DEVICELEN], int nomesg,
if ((masterfd = posix_openpt(flags)) == -1) goto error;
}
rb_fd_fix_cloexec(masterfd);
- if (sigaction(SIGCHLD, &dfl, &old) == -1) goto error;
- if (grantpt(masterfd) == -1) goto grantpt_error;
+ if (rb_grantpt(masterfd) == -1) goto error;
#endif
- if (sigaction(SIGCHLD, &old, NULL) == -1) goto error;
if (unlockpt(masterfd) == -1) goto error;
if ((slavedevice = ptsname(masterfd)) == NULL) goto error;
if (no_mesg(slavedevice, nomesg) == -1) goto error;
@@ -293,8 +285,6 @@ get_device_once(int *master, int *slave, char SlaveName[DEVICELEN], int nomesg,
strlcpy(SlaveName, slavedevice, DEVICELEN);
return 0;
- grantpt_error:
- sigaction(SIGCHLD, &old, NULL);
error:
if (slavefd != -1) close(slavefd);
if (masterfd != -1) close(masterfd);
@@ -346,21 +336,17 @@ get_device_once(int *master, int *slave, char SlaveName[DEVICELEN], int nomesg,
extern char *ptsname(int);
extern int unlockpt(int);
- extern int grantpt(int);
#if defined(__sun)
/* workaround for Solaris 10: grantpt() doesn't work if FD_CLOEXEC is set. [ruby-dev:44688] */
if((masterfd = open("/dev/ptmx", O_RDWR, 0)) == -1) goto error;
- s = signal(SIGCHLD, SIG_DFL);
- if(grantpt(masterfd) == -1) goto error;
+ if(rb_grantpt(masterfd) == -1) goto error;
rb_fd_fix_cloexec(masterfd);
#else
if((masterfd = rb_cloexec_open("/dev/ptmx", O_RDWR, 0)) == -1) goto error;
rb_update_max_fd(masterfd);
- s = signal(SIGCHLD, SIG_DFL);
- if(grantpt(masterfd) == -1) goto error;
+ if(rb_grantpt(masterfd) == -1) goto error;
#endif
- signal(SIGCHLD, s);
if(unlockpt(masterfd) == -1) goto error;
if((slavedevice = ptsname(masterfd)) == NULL) goto error;
if (no_mesg(slavedevice, nomesg) == -1) goto error;