diff options
| -rw-r--r-- | .topdeps | 2 | ||||
| -rw-r--r-- | .topmsg | 31 | ||||
| -rw-r--r-- | hurd/hurdsig.c | 272 |
3 files changed, 176 insertions, 129 deletions
@@ -1 +1 @@ -9a869d822025be8e43b78234997b10bf0cf9d859 +baseline @@ -1,16 +1,15 @@ -Subject: Baseline for our topic branches. - ---- - -This need not strictly be a TopGit branch, but it is for easy synchronization -between different machines. - -As the baseline is merged into the topic branches, it is forward-only. - -To advance it: - - $ echo [SHA1] > .topdeps - $ git commit -m Advance. -- .topdeps - $ tg update - ---- +From: Jeremie Koenig <jk@jk.fr.eu.org> +Subject: [PATCH] Signal code refactoring. + +These patches should not change the current +behavior, although they do fix a few minor bugs which were made +apparent in the process. They are unchanged from my previous post +earlier this month. + + 34f5960 _hurd_internal_post_signal: Split into more functions + 420eec9 _hurd_internal_post_signal: Scope variables more restrictively + 1f5accd _hurd_internal_post_signal: Split out inner functions + 1bb0a1d Hurd signals: refactor check_pending_signals + 1764465 Hurd signals: reindent + 28473d2 Hurd signals: make sigsuspend POSIX-conformant. + 26d091a Hurd signals: fix uninitialized value. diff --git a/hurd/hurdsig.c b/hurd/hurdsig.c index aa82f63413..d300c9eefe 100644 --- a/hurd/hurdsig.c +++ b/hurd/hurdsig.c @@ -452,6 +452,30 @@ abort_all_rpcs (int signo, struct machine_thread_all_state *state, int live) } } +/* Wake up any sigsuspend call that is blocking SS->thread. SS must be + locked. */ +static void +wake_sigsuspend (struct hurd_sigstate *ss) +{ + error_t err; + mach_msg_header_t msg; + + if (ss->suspended == MACH_PORT_NULL) + return; + + /* There is a sigsuspend waiting. Tell it to wake up. */ + msg.msgh_bits = MACH_MSGH_BITS (MACH_MSG_TYPE_MAKE_SEND, 0); + msg.msgh_remote_port = ss->suspended; + msg.msgh_local_port = MACH_PORT_NULL; + /* These values do not matter. */ + msg.msgh_id = 8675309; /* Jenny, Jenny. */ + ss->suspended = MACH_PORT_NULL; + err = __mach_msg (&msg, MACH_SEND_MSG, sizeof msg, 0, + MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE, + MACH_PORT_NULL); + assert_perror (err); +} + struct hurd_signal_preemptor *_hurdsig_preemptors = 0; sigset_t _hurdsig_preempted_set; @@ -462,35 +486,18 @@ weak_alias (_hurdsig_preemptors, _hurdsig_preempters) #define STOPSIGS (sigmask (SIGTTIN) | sigmask (SIGTTOU) | \ sigmask (SIGSTOP) | sigmask (SIGTSTP)) -/* Deliver a signal. SS is not locked. */ -void -_hurd_internal_post_signal (struct hurd_sigstate *ss, - int signo, struct hurd_signal_detail *detail, - mach_port_t reply_port, - mach_msg_type_name_t reply_port_type, - int untraced) +/* Actual delivery of a single signal. Called with SS unlocked. When + the signal is delivered, return 1 with SS locked. If the signal is + being traced, return 0 with SS unlocked. */ +static int +post_signal (struct hurd_sigstate *ss, + int signo, struct hurd_signal_detail *detail, + int untraced, void (*reply) (void)) { - error_t err; struct machine_thread_all_state thread_state; enum { stop, ignore, core, term, handle } act; - sighandler_t handler; - sigset_t pending; int ss_suspended; - /* Reply to this sig_post message. */ - __typeof (__msg_sig_post_reply) *reply_rpc - = (untraced ? __msg_sig_post_untraced_reply : __msg_sig_post_reply); - void reply (void) - { - error_t err; - if (reply_port == MACH_PORT_NULL) - return; - err = (*reply_rpc) (reply_port, reply_port_type, 0); - reply_port = MACH_PORT_NULL; - if (err != MACH_SEND_INVALID_DEST) /* Ignore dead reply port. */ - assert_perror (err); - } - /* Mark the signal as pending. */ void mark_pending (void) { @@ -554,19 +561,23 @@ _hurd_internal_post_signal (struct hurd_sigstate *ss, ss_suspended = 1; } + error_t err; + sighandler_t handler; + if (signo == 0) { if (untraced) - /* This is PTRACE_CONTINUE. */ - resume (); + { + /* This is PTRACE_CONTINUE. */ + act = ignore; + resume (); + } /* This call is just to check for pending signals. */ __spin_lock (&ss->lock); - goto check_pending_signals; + return 1; } - post_signal: - thread_state.set = 0; /* We know nothing. */ __spin_lock (&ss->lock); @@ -629,7 +640,7 @@ _hurd_internal_post_signal (struct hurd_sigstate *ss, suspend (); __spin_unlock (&ss->lock); reply (); - return; + return 0; } handler = ss->actions[signo].sa_handler; @@ -873,7 +884,7 @@ _hurd_internal_post_signal (struct hurd_sigstate *ss, as a unit. */ crit ? 0 : signo, 1, &thread_state, &state_changed, - &reply) + reply) != MACH_PORT_NULL); if (crit) @@ -960,6 +971,9 @@ _hurd_internal_post_signal (struct hurd_sigstate *ss, && signo != SIGILL && signo != SIGTRAP) ss->actions[signo].sa_handler = SIG_DFL; + /* Any sigsuspend call must return after the handler does. */ + wake_sigsuspend (ss); + /* Start the thread running the handler (or possibly waiting for an RPC reply before running the handler). */ err = __thread_set_state (ss->thread, MACHINE_THREAD_STATE_FLAVOR, @@ -973,95 +987,129 @@ _hurd_internal_post_signal (struct hurd_sigstate *ss, } } - /* The signal has either been ignored or is now being handled. We can - consider it delivered and reply to the killer. */ - reply (); + return 1; +} - /* We get here unless the signal was fatal. We still hold SS->lock. - Check for pending signals, and loop to post them. */ - { - /* Return nonzero if SS has any signals pending we should worry about. - We don't worry about any pending signals if we are stopped, nor if - SS is in a critical section. We are guaranteed to get a sig_post - message before any of them become deliverable: either the SIGCONT - signal, or a sig_post with SIGNO==0 as an explicit poll when the - thread finishes its critical section. */ - inline int signals_pending (void) - { - if (_hurd_stopped || __spin_lock_locked (&ss->critical_section_lock)) - return 0; - return pending = ss->pending & ~ss->blocked; - } +/* Return the set of pending signals in SS which should be delivered. */ +static sigset_t +pending_signals (struct hurd_sigstate *ss) +{ + /* We don't worry about any pending signals if we are stopped, nor if + SS is in a critical section. We are guaranteed to get a sig_post + message before any of them become deliverable: either the SIGCONT + signal, or a sig_post with SIGNO==0 as an explicit poll when the + thread finishes its critical section. */ + if (_hurd_stopped || __spin_lock_locked (&ss->critical_section_lock)) + return 0; - check_pending_signals: - untraced = 0; + return ss->pending & ~ss->blocked; +} - if (signals_pending ()) - { - for (signo = 1; signo < NSIG; ++signo) - if (__sigismember (&pending, signo)) - { - deliver_pending: - __sigdelset (&ss->pending, signo); - *detail = ss->pending_data[signo]; - __spin_unlock (&ss->lock); - goto post_signal; - } - } +/* Post the specified pending signals in SS and return 1. If one of + them is traced, abort immediately and return 0. SS must be locked on + entry and will be unlocked in all cases. */ +static int +post_pending (struct hurd_sigstate *ss, sigset_t pending, void (*reply) (void)) +{ + int signo; + struct hurd_signal_detail detail; - /* No pending signals left undelivered for this thread. - If we were sent signal 0, we need to check for pending - signals for all threads. */ - if (signo == 0) - { - __spin_unlock (&ss->lock); - __mutex_lock (&_hurd_siglock); - for (ss = _hurd_sigstates; ss != NULL; ss = ss->next) - { - __spin_lock (&ss->lock); - for (signo = 1; signo < NSIG; ++signo) - if (__sigismember (&ss->pending, signo) - && (!__sigismember (&ss->blocked, signo) - /* We "deliver" immediately pending blocked signals whose - action might be to ignore, so that if ignored they are - dropped right away. */ - || ss->actions[signo].sa_handler == SIG_IGN - || ss->actions[signo].sa_handler == SIG_DFL)) - { - __mutex_unlock (&_hurd_siglock); - goto deliver_pending; - } - __spin_unlock (&ss->lock); - } - __mutex_unlock (&_hurd_siglock); - } - else + for (signo = 1; signo < NSIG; ++signo) + if (__sigismember (&pending, signo)) { - /* No more signals pending; SS->lock is still locked. - Wake up any sigsuspend call that is blocking SS->thread. */ - if (ss->suspended != MACH_PORT_NULL) - { - /* There is a sigsuspend waiting. Tell it to wake up. */ - error_t err; - mach_msg_header_t msg; - msg.msgh_bits = MACH_MSGH_BITS (MACH_MSG_TYPE_MAKE_SEND, 0); - msg.msgh_remote_port = ss->suspended; - msg.msgh_local_port = MACH_PORT_NULL; - /* These values do not matter. */ - msg.msgh_id = 8675309; /* Jenny, Jenny. */ - ss->suspended = MACH_PORT_NULL; - err = __mach_msg (&msg, MACH_SEND_MSG, sizeof msg, 0, - MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE, - MACH_PORT_NULL); - assert_perror (err); - } + __sigdelset (&ss->pending, signo); + detail = ss->pending_data[signo]; __spin_unlock (&ss->lock); + + /* Will reacquire the lock, except if the signal is traced. */ + if (! post_signal (ss, signo, &detail, 0, reply)) + return 0; } - } - /* All pending signals delivered to all threads. - Now we can send the reply message even for signal 0. */ - reply (); + /* No more signals pending; SS->lock is still locked. */ + __spin_unlock (&ss->lock); + + return 1; +} + +/* Post all the pending signals of all threads and return 1. If a traced + signal is encountered, abort immediately and return 0. */ +static int +post_all_pending_signals (void (*reply) (void)) +{ + struct hurd_sigstate *ss; + sigset_t pending = 0; + + for (;;) + { + __mutex_lock (&_hurd_siglock); + for (ss = _hurd_sigstates; ss != NULL; ss = ss->next) + { + __spin_lock (&ss->lock); + + pending = pending_signals (ss); + if (pending) + /* post_pending() below will unlock SS. */ + break; + + __spin_unlock (&ss->lock); + } + __mutex_unlock (&_hurd_siglock); + + if (! pending) + return 1; + if (! post_pending (ss, pending, reply)) + return 0; + } +} + +/* Deliver a signal. SS is not locked. */ +void +_hurd_internal_post_signal (struct hurd_sigstate *ss, + int signo, struct hurd_signal_detail *detail, + mach_port_t reply_port, + mach_msg_type_name_t reply_port_type, + int untraced) +{ + /* Reply to this sig_post message. */ + __typeof (__msg_sig_post_reply) *reply_rpc + = (untraced ? __msg_sig_post_untraced_reply : __msg_sig_post_reply); + void reply (void) + { + error_t err; + if (reply_port == MACH_PORT_NULL) + return; + err = (*reply_rpc) (reply_port, reply_port_type, 0); + reply_port = MACH_PORT_NULL; + if (err != MACH_SEND_INVALID_DEST) /* Ignore dead reply port. */ + assert_perror (err); + } + + if (! post_signal (ss, signo, detail, untraced, reply)) + return; + + /* The signal was neither fatal nor traced. We still hold SS->lock. */ + if (signo != 0) + { + /* The signal has either been ignored or is now being handled. We can + consider it delivered and reply to the killer. */ + reply (); + + /* Post any pending signals for this thread. */ + if (! post_pending (ss, pending_signals (ss), reply)) + return; + } + else + { + /* We need to check for pending signals for all threads. */ + __spin_unlock (&ss->lock); + if (! post_all_pending_signals (reply)) + return; + + /* All pending signals delivered to all threads. + Now we can send the reply message even for signal 0. */ + reply (); + } } /* Decide whether REFPORT enables the sender to send us a SIGNO signal. |