diff options
Diffstat (limited to 'libpthread/linuxthreads/manager.c')
| -rw-r--r-- | libpthread/linuxthreads/manager.c | 1123 |
1 files changed, 1123 insertions, 0 deletions
diff --git a/libpthread/linuxthreads/manager.c b/libpthread/linuxthreads/manager.c new file mode 100644 index 000000000..d854610db --- /dev/null +++ b/libpthread/linuxthreads/manager.c @@ -0,0 +1,1123 @@ +/* Linuxthreads - a simple clone()-based implementation of Posix */ +/* threads for Linux. */ +/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */ +/* */ +/* This program is free software; you can redistribute it and/or */ +/* modify it under the terms of the GNU Library General Public License */ +/* as published by the Free Software Foundation; either version 2 */ +/* of the License, or (at your option) any later version. */ +/* */ +/* This program is distributed in the hope that it will be useful, */ +/* but WITHOUT ANY WARRANTY; without even the implied warranty of */ +/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */ +/* GNU Library General Public License for more details. */ + +/* The "thread manager" thread: manages creation and termination of threads */ + +#include <assert.h> +#include <errno.h> +#include <sched.h> +#include <stddef.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <sys/poll.h> /* for poll */ +#include <sys/mman.h> /* for mmap */ +#include <sys/param.h> +#include <sys/time.h> +#include <sys/wait.h> /* for waitpid macros */ +#include <locale.h> /* for __uselocale */ +#include <resolv.h> /* for __resp */ + +#include "pthread.h" +#include "internals.h" +#include "spinlock.h" +#include "restart.h" +#include "semaphore.h" +#include <not-cancel.h> + +#define __clone clone + +/* For debugging purposes put the maximum number of threads in a variable. */ +const int __linuxthreads_pthread_threads_max = PTHREAD_THREADS_MAX; + +#ifndef THREAD_SELF +/* Indicate whether at least one thread has a user-defined stack (if 1), + or if all threads have stacks supplied by LinuxThreads (if 0). */ +int __pthread_nonstandard_stacks; +#endif + +/* Number of active entries in __pthread_handles (used by gdb) */ +volatile int __pthread_handles_num = 2; + +/* Whether to use debugger additional actions for thread creation + (set to 1 by gdb) */ +volatile int __pthread_threads_debug; + +/* Globally enabled events. */ +volatile td_thr_events_t __pthread_threads_events; + +/* Pointer to thread descriptor with last event. */ +volatile pthread_descr __pthread_last_event; + +static pthread_descr manager_thread; + +/* Mapping from stack segment to thread descriptor. */ +/* Stack segment numbers are also indices into the __pthread_handles array. */ +/* Stack segment number 0 is reserved for the initial thread. */ + +#if FLOATING_STACKS +# define thread_segment(seq) NULL +#else +static inline pthread_descr thread_segment(int seg) +{ +# ifdef _STACK_GROWS_UP + return (pthread_descr)(THREAD_STACK_START_ADDRESS + (seg - 1) * STACK_SIZE) + + 1; +# else + return (pthread_descr)(THREAD_STACK_START_ADDRESS - (seg - 1) * STACK_SIZE) + - 1; +# endif +} +#endif + +/* Flag set in signal handler to record child termination */ + +static volatile int terminated_children; + +/* Flag set when the initial thread is blocked on pthread_exit waiting + for all other threads to terminate */ + +static int main_thread_exiting; + +/* Counter used to generate unique thread identifier. + Thread identifier is pthread_threads_counter + segment. */ + +static pthread_t pthread_threads_counter; + +/* Forward declarations */ + +static int pthread_handle_create(pthread_t *thread, const pthread_attr_t *attr, + void * (*start_routine)(void *), void *arg, + sigset_t *mask, int father_pid, + int report_events, + td_thr_events_t *event_maskp); +static void pthread_handle_free(pthread_t th_id); +static void pthread_handle_exit(pthread_descr issuing_thread, int exitcode) + __attribute__ ((noreturn)); +static void pthread_reap_children(void); +static void pthread_kill_all_threads(int sig, int main_thread_also); +static void pthread_for_each_thread(void *arg, + void (*fn)(void *, pthread_descr)); + +/* The server thread managing requests for thread creation and termination */ + +int +__attribute__ ((noreturn)) +__pthread_manager(void *arg) +{ + pthread_descr self = manager_thread = arg; + int reqfd = __pthread_manager_reader; + struct pollfd ufd; + sigset_t manager_mask; + int n; + struct pthread_request request; + + /* If we have special thread_self processing, initialize it. */ +#ifdef INIT_THREAD_SELF + INIT_THREAD_SELF(self, 1); +#endif +#if !(USE_TLS && HAVE___THREAD) + /* Set the error variable. */ + self->p_errnop = &self->p_errno; + self->p_h_errnop = &self->p_h_errno; +#endif + /* Block all signals except __pthread_sig_cancel and SIGTRAP */ + sigfillset(&manager_mask); + sigdelset(&manager_mask, __pthread_sig_cancel); /* for thread termination */ + sigdelset(&manager_mask, SIGTRAP); /* for debugging purposes */ + if (__pthread_threads_debug && __pthread_sig_debug > 0) + sigdelset(&manager_mask, __pthread_sig_debug); + sigprocmask(SIG_SETMASK, &manager_mask, NULL); + /* Raise our priority to match that of main thread */ + __pthread_manager_adjust_prio(__pthread_main_thread->p_priority); + /* Synchronize debugging of the thread manager */ + n = TEMP_FAILURE_RETRY(read_not_cancel(reqfd, (char *)&request, + sizeof(request))); + ASSERT(n == sizeof(request) && request.req_kind == REQ_DEBUG); + ufd.fd = reqfd; + ufd.events = POLLIN; + /* Enter server loop */ + while(1) { + n = __poll(&ufd, 1, 2000); + + /* Check for termination of the main thread */ + if (getppid() == 1) { + pthread_kill_all_threads(SIGKILL, 0); + _exit(0); + } + /* Check for dead children */ + if (terminated_children) { + terminated_children = 0; + pthread_reap_children(); + } + /* Read and execute request */ + if (n == 1 && (ufd.revents & POLLIN)) { + n = TEMP_FAILURE_RETRY(read_not_cancel(reqfd, (char *)&request, + sizeof(request))); +#ifdef DEBUG + if (n < 0) { + char d[64]; + write(STDERR_FILENO, d, snprintf(d, sizeof(d), "*** read err %m\n")); + } else if (n != sizeof(request)) { + write(STDERR_FILENO, "*** short read in manager\n", 26); + } +#endif + + switch(request.req_kind) { + case REQ_CREATE: + request.req_thread->p_retcode = + pthread_handle_create((pthread_t *) &request.req_thread->p_retval, + request.req_args.create.attr, + request.req_args.create.fn, + request.req_args.create.arg, + &request.req_args.create.mask, + request.req_thread->p_pid, + request.req_thread->p_report_events, + &request.req_thread->p_eventbuf.eventmask); + restart(request.req_thread); + break; + case REQ_FREE: + pthread_handle_free(request.req_args.free.thread_id); + break; + case REQ_PROCESS_EXIT: + pthread_handle_exit(request.req_thread, + request.req_args.exit.code); + /* NOTREACHED */ + break; + case REQ_MAIN_THREAD_EXIT: + main_thread_exiting = 1; + /* Reap children in case all other threads died and the signal handler + went off before we set main_thread_exiting to 1, and therefore did + not do REQ_KICK. */ + pthread_reap_children(); + + if (__pthread_main_thread->p_nextlive == __pthread_main_thread) { + restart(__pthread_main_thread); + /* The main thread will now call exit() which will trigger an + __on_exit handler, which in turn will send REQ_PROCESS_EXIT + to the thread manager. In case you are wondering how the + manager terminates from its loop here. */ + } + break; + case REQ_POST: + sem_post(request.req_args.post); + break; + case REQ_DEBUG: + /* Make gdb aware of new thread and gdb will restart the + new thread when it is ready to handle the new thread. */ + if (__pthread_threads_debug && __pthread_sig_debug > 0) + raise(__pthread_sig_debug); + break; + case REQ_KICK: + /* This is just a prod to get the manager to reap some + threads right away, avoiding a potential delay at shutdown. */ + break; + case REQ_FOR_EACH_THREAD: + pthread_for_each_thread(request.req_args.for_each.arg, + request.req_args.for_each.fn); + restart(request.req_thread); + break; + } + } + } +} + +int __pthread_manager_event(void *arg) +{ + pthread_descr self = arg; + /* If we have special thread_self processing, initialize it. */ +#ifdef INIT_THREAD_SELF + INIT_THREAD_SELF(self, 1); +#endif + + /* Get the lock the manager will free once all is correctly set up. */ + __pthread_lock (THREAD_GETMEM(self, p_lock), NULL); + /* Free it immediately. */ + __pthread_unlock (THREAD_GETMEM(self, p_lock)); + + return __pthread_manager(arg); +} + +/* Process creation */ + +static int +__attribute__ ((noreturn)) +pthread_start_thread(void *arg) +{ + pthread_descr self = (pthread_descr) arg; + struct pthread_request request; + void * outcome; +#if HP_TIMING_AVAIL + hp_timing_t tmpclock; +#endif + /* Initialize special thread_self processing, if any. */ +#ifdef INIT_THREAD_SELF + INIT_THREAD_SELF(self, self->p_nr); +#endif +#if HP_TIMING_AVAIL + HP_TIMING_NOW (tmpclock); + THREAD_SETMEM (self, p_cpuclock_offset, tmpclock); +#endif + /* Make sure our pid field is initialized, just in case we get there + before our father has initialized it. */ + THREAD_SETMEM(self, p_pid, __getpid()); + /* Initial signal mask is that of the creating thread. (Otherwise, + we'd just inherit the mask of the thread manager.) */ + sigprocmask(SIG_SETMASK, &self->p_start_args.mask, NULL); + /* Set the scheduling policy and priority for the new thread, if needed */ + if (THREAD_GETMEM(self, p_start_args.schedpolicy) >= 0) + /* Explicit scheduling attributes were provided: apply them */ + __sched_setscheduler(THREAD_GETMEM(self, p_pid), + THREAD_GETMEM(self, p_start_args.schedpolicy), + &self->p_start_args.schedparam); + else if (manager_thread->p_priority > 0) + /* Default scheduling required, but thread manager runs in realtime + scheduling: switch new thread to SCHED_OTHER policy */ + { + struct sched_param default_params; + default_params.sched_priority = 0; + __sched_setscheduler(THREAD_GETMEM(self, p_pid), + SCHED_OTHER, &default_params); + } +#if !(USE_TLS && HAVE___THREAD) + /* Initialize thread-locale current locale to point to the global one. + With __thread support, the variable's initializer takes care of this. */ + __uselocale (LC_GLOBAL_LOCALE); +#else + /* Initialize __resp. */ + __resp = &self->p_res; +#endif + /* Make gdb aware of new thread */ + if (__pthread_threads_debug && __pthread_sig_debug > 0) { + request.req_thread = self; + request.req_kind = REQ_DEBUG; + TEMP_FAILURE_RETRY(write_not_cancel(__pthread_manager_request, + (char *) &request, sizeof(request))); + suspend(self); + } + /* Run the thread code */ + outcome = self->p_start_args.start_routine(THREAD_GETMEM(self, + p_start_args.arg)); + /* Exit with the given return value */ + __pthread_do_exit(outcome, CURRENT_STACK_FRAME); +} + +static int +__attribute__ ((noreturn)) +pthread_start_thread_event(void *arg) +{ + pthread_descr self = (pthread_descr) arg; + +#ifdef INIT_THREAD_SELF + INIT_THREAD_SELF(self, self->p_nr); +#endif + /* Make sure our pid field is initialized, just in case we get there + before our father has initialized it. */ + THREAD_SETMEM(self, p_pid, __getpid()); + /* Get the lock the manager will free once all is correctly set up. */ + __pthread_lock (THREAD_GETMEM(self, p_lock), NULL); + /* Free it immediately. */ + __pthread_unlock (THREAD_GETMEM(self, p_lock)); + + /* Continue with the real function. */ + pthread_start_thread (arg); +} + +#if defined USE_TLS && !FLOATING_STACKS +# error "TLS can only work with floating stacks" +#endif + +static int pthread_allocate_stack(const pthread_attr_t *attr, + pthread_descr default_new_thread, + int pagesize, + char ** out_new_thread, + char ** out_new_thread_bottom, + char ** out_guardaddr, + size_t * out_guardsize, + size_t * out_stacksize) +{ + pthread_descr new_thread; + char * new_thread_bottom; + char * guardaddr; + size_t stacksize, guardsize; + +#ifdef USE_TLS + /* TLS cannot work with fixed thread descriptor addresses. */ + assert (default_new_thread == NULL); +#endif + + if (attr != NULL && attr->__stackaddr_set) + { +#ifdef _STACK_GROWS_UP + /* The user provided a stack. */ +# ifdef USE_TLS + /* This value is not needed. */ + new_thread = (pthread_descr) attr->__stackaddr; + new_thread_bottom = (char *) new_thread; +# else + new_thread = (pthread_descr) attr->__stackaddr; + new_thread_bottom = (char *) (new_thread + 1); +# endif + guardaddr = attr->__stackaddr + attr->__stacksize; + guardsize = 0; +#else + /* The user provided a stack. For now we interpret the supplied + address as 1 + the highest addr. in the stack segment. If a + separate register stack is needed, we place it at the low end + of the segment, relying on the associated stacksize to + determine the low end of the segment. This differs from many + (but not all) other pthreads implementations. The intent is + that on machines with a single stack growing toward higher + addresses, stackaddr would be the lowest address in the stack + segment, so that it is consistently close to the initial sp + value. */ +# ifdef USE_TLS + new_thread = (pthread_descr) attr->__stackaddr; +# else + new_thread = + (pthread_descr) ((long)(attr->__stackaddr) & -sizeof(void *)) - 1; +# endif + new_thread_bottom = (char *) attr->__stackaddr - attr->__stacksize; + guardaddr = new_thread_bottom; + guardsize = 0; +#endif +#ifndef THREAD_SELF + __pthread_nonstandard_stacks = 1; +#endif +#ifndef USE_TLS + /* Clear the thread data structure. */ + memset (new_thread, '\0', sizeof (*new_thread)); +#endif + stacksize = attr->__stacksize; + } + else + { +#ifdef NEED_SEPARATE_REGISTER_STACK + const size_t granularity = 2 * pagesize; + /* Try to make stacksize/2 a multiple of pagesize */ +#else + const size_t granularity = pagesize; +#endif + void *map_addr; + + /* Allocate space for stack and thread descriptor at default address */ +#if FLOATING_STACKS + if (attr != NULL) + { + guardsize = page_roundup (attr->__guardsize, granularity); + stacksize = __pthread_max_stacksize - guardsize; + stacksize = MIN (stacksize, + page_roundup (attr->__stacksize, granularity)); + } + else + { + guardsize = granularity; + stacksize = __pthread_max_stacksize - guardsize; + } + + map_addr = mmap(NULL, stacksize + guardsize, + PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (map_addr == MAP_FAILED) + /* No more memory available. */ + return -1; + +# ifdef NEED_SEPARATE_REGISTER_STACK + guardaddr = map_addr + stacksize / 2; + if (guardsize > 0) + mprotect (guardaddr, guardsize, PROT_NONE); + + new_thread_bottom = (char *) map_addr; +# ifdef USE_TLS + new_thread = ((pthread_descr) (new_thread_bottom + stacksize + + guardsize)); +# else + new_thread = ((pthread_descr) (new_thread_bottom + stacksize + + guardsize)) - 1; +# endif +# elif _STACK_GROWS_DOWN + guardaddr = map_addr; + if (guardsize > 0) + mprotect (guardaddr, guardsize, PROT_NONE); + + new_thread_bottom = (char *) map_addr + guardsize; +# ifdef USE_TLS + new_thread = ((pthread_descr) (new_thread_bottom + stacksize)); +# else + new_thread = ((pthread_descr) (new_thread_bottom + stacksize)) - 1; +# endif +# elif _STACK_GROWS_UP + guardaddr = map_addr + stacksize; + if (guardsize > 0) + mprotect (guardaddr, guardsize, PROT_NONE); + + new_thread = (pthread_descr) map_addr; +# ifdef USE_TLS + new_thread_bottom = (char *) new_thread; +# else + new_thread_bottom = (char *) (new_thread + 1); +# endif +# else +# error You must define a stack direction +# endif /* Stack direction */ +#else /* !FLOATING_STACKS */ +# if !defined NEED_SEPARATE_REGISTER_STACK && defined _STACK_GROWS_DOWN + void *res_addr; +# endif + + if (attr != NULL) + { + guardsize = page_roundup (attr->__guardsize, granularity); + stacksize = STACK_SIZE - guardsize; + stacksize = MIN (stacksize, + page_roundup (attr->__stacksize, granularity)); + } + else + { + guardsize = granularity; + stacksize = STACK_SIZE - granularity; + } + +# ifdef NEED_SEPARATE_REGISTER_STACK + new_thread = default_new_thread; + new_thread_bottom = (char *) (new_thread + 1) - stacksize - guardsize; + /* Includes guard area, unlike the normal case. Use the bottom + end of the segment as backing store for the register stack. + Needed on IA64. In this case, we also map the entire stack at + once. According to David Mosberger, that's cheaper. It also + avoids the risk of intermittent failures due to other mappings + in the same region. The cost is that we might be able to map + slightly fewer stacks. */ + + /* First the main stack: */ + map_addr = (caddr_t)((char *)(new_thread + 1) - stacksize / 2); + res_addr = mmap(map_addr, stacksize / 2, + PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (res_addr != map_addr) + { + /* Bad luck, this segment is already mapped. */ + if (res_addr != MAP_FAILED) + munmap(res_addr, stacksize / 2); + return -1; + } + /* Then the register stack: */ + map_addr = (caddr_t)new_thread_bottom; + res_addr = mmap(map_addr, stacksize/2, + PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (res_addr != map_addr) + { + if (res_addr != MAP_FAILED) + munmap(res_addr, stacksize / 2); + munmap((caddr_t)((char *)(new_thread + 1) - stacksize/2), + stacksize/2); + return -1; + } + + guardaddr = new_thread_bottom + stacksize/2; + /* We leave the guard area in the middle unmapped. */ +# else /* !NEED_SEPARATE_REGISTER_STACK */ +# ifdef _STACK_GROWS_DOWN + new_thread = default_new_thread; + new_thread_bottom = (char *) (new_thread + 1) - stacksize; + map_addr = new_thread_bottom - guardsize; + res_addr = mmap(map_addr, stacksize + guardsize, + PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (res_addr != map_addr) + { + /* Bad luck, this segment is already mapped. */ + if (res_addr != MAP_FAILED) + munmap (res_addr, stacksize + guardsize); + return -1; + } + + /* We manage to get a stack. Protect the guard area pages if + necessary. */ + guardaddr = map_addr; + if (guardsize > 0) + mprotect (guardaddr, guardsize, PROT_NONE); +# else + /* The thread description goes at the bottom of this area, and + * the stack starts directly above it. + */ + new_thread = (pthread_descr)((unsigned long)default_new_thread &~ (STACK_SIZE - 1)); + map_addr = mmap(new_thread, stacksize + guardsize, + PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (map_addr == MAP_FAILED) + return -1; + + new_thread_bottom = map_addr + sizeof(*new_thread); + guardaddr = map_addr + stacksize; + if (guardsize > 0) + mprotect (guardaddr, guardsize, PROT_NONE); + +# endif /* stack direction */ +# endif /* !NEED_SEPARATE_REGISTER_STACK */ +#endif /* !FLOATING_STACKS */ + } + *out_new_thread = (char *) new_thread; + *out_new_thread_bottom = new_thread_bottom; + *out_guardaddr = guardaddr; + *out_guardsize = guardsize; +#ifdef NEED_SEPARATE_REGISTER_STACK + *out_stacksize = stacksize / 2; +#else + *out_stacksize = stacksize; +#endif + return 0; +} + +static int pthread_handle_create(pthread_t *thread, const pthread_attr_t *attr, + void * (*start_routine)(void *), void *arg, + sigset_t * mask, int father_pid, + int report_events, + td_thr_events_t *event_maskp) +{ + size_t sseg; + int pid; + pthread_descr new_thread; + char *stack_addr; + char * new_thread_bottom; + pthread_t new_thread_id; + char *guardaddr = NULL; + size_t guardsize = 0, stksize = 0; + int pagesize = __getpagesize(); + int saved_errno = 0; + +#ifdef USE_TLS + new_thread = _dl_allocate_tls (NULL); + if (new_thread == NULL) + return EAGAIN; +# if TLS_DTV_AT_TP + /* pthread_descr is below TP. */ + new_thread = (pthread_descr) ((char *) new_thread - TLS_PRE_TCB_SIZE); +# endif +#else + /* Prevent warnings. */ + new_thread = NULL; +#endif + + /* First check whether we have to change the policy and if yes, whether + we can do this. Normally this should be done by examining the + return value of the __sched_setscheduler call in pthread_start_thread + but this is hard to implement. FIXME */ + if (attr != NULL && attr->__schedpolicy != SCHED_OTHER && geteuid () != 0) + return EPERM; + /* Find a free segment for the thread, and allocate a stack if needed */ + for (sseg = 2; ; sseg++) + { + if (sseg >= PTHREAD_THREADS_MAX) + { +#ifdef USE_TLS +# if TLS_DTV_AT_TP + new_thread = (pthread_descr) ((char *) new_thread + TLS_PRE_TCB_SIZE); +# endif + _dl_deallocate_tls (new_thread, true); +#endif + return EAGAIN; + } + if (__pthread_handles[sseg].h_descr != NULL) + continue; + if (pthread_allocate_stack(attr, thread_segment(sseg), + pagesize, &stack_addr, &new_thread_bottom, + &guardaddr, &guardsize, &stksize) == 0) + { +#ifdef USE_TLS + new_thread->p_stackaddr = stack_addr; +#else + new_thread = (pthread_descr) stack_addr; +#endif + break; +#ifndef __ARCH_HAS_MMU__ + } else { + /* When there is MMU, mmap () is used to allocate the stack. If one + * segment is already mapped, we should continue to see if we can + * use the next one. However, when there is no MMU, malloc () is used. + * It's waste of CPU cycles to continue to try if it fails. */ + return EAGAIN; +#endif + } + } + __pthread_handles_num++; + /* Allocate new thread identifier */ + pthread_threads_counter += PTHREAD_THREADS_MAX; + new_thread_id = sseg + pthread_threads_counter; + /* Initialize the thread descriptor. Elements which have to be + initialized to zero already have this value. */ +#if !defined USE_TLS || !TLS_DTV_AT_TP + new_thread->p_header.data.tcb = new_thread; + new_thread->p_header.data.self = new_thread; +#endif +#if TLS_MULTIPLE_THREADS_IN_TCB || !defined USE_TLS || !TLS_DTV_AT_TP + new_thread->p_multiple_threads = 1; +#endif + new_thread->p_tid = new_thread_id; + new_thread->p_lock = &(__pthread_handles[sseg].h_lock); + new_thread->p_cancelstate = PTHREAD_CANCEL_ENABLE; + new_thread->p_canceltype = PTHREAD_CANCEL_DEFERRED; +#if !(USE_TLS && HAVE___THREAD) + new_thread->p_errnop = &new_thread->p_errno; + new_thread->p_h_errnop = &new_thread->p_h_errno; + new_thread->p_resp = &new_thread->p_res; +#endif + new_thread->p_guardaddr = guardaddr; + new_thread->p_guardsize = guardsize; + new_thread->p_nr = sseg; + new_thread->p_inheritsched = attr ? attr->__inheritsched : 0; + new_thread->p_alloca_cutoff = stksize / 4 > __MAX_ALLOCA_CUTOFF + ? __MAX_ALLOCA_CUTOFF : stksize / 4; + /* Initialize the thread handle */ + __pthread_init_lock(&__pthread_handles[sseg].h_lock); + __pthread_handles[sseg].h_descr = new_thread; + __pthread_handles[sseg].h_bottom = new_thread_bottom; + /* Determine scheduling parameters for the thread */ + new_thread->p_start_args.schedpolicy = -1; + if (attr != NULL) { + new_thread->p_detached = attr->__detachstate; + new_thread->p_userstack = attr->__stackaddr_set; + + switch(attr->__inheritsched) { + case PTHREAD_EXPLICIT_SCHED: + new_thread->p_start_args.schedpolicy = attr->__schedpolicy; + memcpy (&new_thread->p_start_args.schedparam, &attr->__schedparam, + sizeof (struct sched_param)); + break; + case PTHREAD_INHERIT_SCHED: + new_thread->p_start_args.schedpolicy = __sched_getscheduler(father_pid); + __sched_getparam(father_pid, &new_thread->p_start_args.schedparam); + break; + } + new_thread->p_priority = + new_thread->p_start_args.schedparam.sched_priority; + } + /* Finish setting up arguments to pthread_start_thread */ + new_thread->p_start_args.start_routine = start_routine; + new_thread->p_start_args.arg = arg; + new_thread->p_start_args.mask = *mask; + /* Make the new thread ID available already now. If any of the later + functions fail we return an error value and the caller must not use + the stored thread ID. */ + *thread = new_thread_id; + /* Raise priority of thread manager if needed */ + __pthread_manager_adjust_prio(new_thread->p_priority); + /* Do the cloning. We have to use two different functions depending + on whether we are debugging or not. */ + pid = 0; /* Note that the thread never can have PID zero. */ + if (report_events) + { + /* See whether the TD_CREATE event bit is set in any of the + masks. */ + int idx = __td_eventword (TD_CREATE); + uint32_t mask = __td_eventmask (TD_CREATE); + + if ((mask & (__pthread_threads_events.event_bits[idx] + | event_maskp->event_bits[idx])) != 0) + { + /* Lock the mutex the child will use now so that it will stop. */ + __pthread_lock(new_thread->p_lock, NULL); + + /* We have to report this event. */ +#ifdef NEED_SEPARATE_REGISTER_STACK + /* Perhaps this version should be used on all platforms. But + this requires that __clone2 be uniformly supported + everywhere. + + And there is some argument for changing the __clone2 + interface to pass sp and bsp instead, making it more IA64 + specific, but allowing stacks to grow outward from each + other, to get less paging and fewer mmaps. */ + pid = __clone2(pthread_start_thread_event, + (void **)new_thread_bottom, + (char *)stack_addr - new_thread_bottom, + CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | + __pthread_sig_cancel, new_thread); +#elif _STACK_GROWS_UP + pid = __clone(pthread_start_thread_event, (void *) new_thread_bottom, + CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | + __pthread_sig_cancel, new_thread); +#else + pid = __clone(pthread_start_thread_event, stack_addr, + CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | + __pthread_sig_cancel, new_thread); +#endif + saved_errno = errno; + if (pid != -1) + { + /* Now fill in the information about the new thread in + the newly created thread's data structure. We cannot let + the new thread do this since we don't know whether it was + already scheduled when we send the event. */ + new_thread->p_eventbuf.eventdata = new_thread; + new_thread->p_eventbuf.eventnum = TD_CREATE; + __pthread_last_event = new_thread; + + /* We have to set the PID here since the callback function + in the debug library will need it and we cannot guarantee + the child got scheduled before the debugger. */ + new_thread->p_pid = pid; + + /* Now call the function which signals the event. */ + __linuxthreads_create_event (); + + /* Now restart the thread. */ + __pthread_unlock(new_thread->p_lock); + } + } + } + if (pid == 0) + { +#ifdef NEED_SEPARATE_REGISTER_STACK + pid = __clone2(pthread_start_thread, + (void **)new_thread_bottom, + (char *)stack_addr - new_thread_bottom, + CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | + __pthread_sig_cancel, new_thread); +#elif _STACK_GROWS_UP + pid = __clone(pthread_start_thread, (void *) new_thread_bottom, + CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | + __pthread_sig_cancel, new_thread); +#else + pid = __clone(pthread_start_thread, stack_addr, + CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | + __pthread_sig_cancel, new_thread); +#endif /* !NEED_SEPARATE_REGISTER_STACK */ + saved_errno = errno; + } + /* Check if cloning succeeded */ + if (pid == -1) { + /* Free the stack if we allocated it */ + if (attr == NULL || !attr->__stackaddr_set) + { +#ifdef NEED_SEPARATE_REGISTER_STACK + size_t stacksize = ((char *)(new_thread->p_guardaddr) + - new_thread_bottom); + munmap((caddr_t)new_thread_bottom, + 2 * stacksize + new_thread->p_guardsize); +#elif _STACK_GROWS_UP +# ifdef USE_TLS + size_t stacksize = guardaddr - stack_addr; + munmap(stack_addr, stacksize + guardsize); +# else + size_t stacksize = guardaddr - (char *)new_thread; + munmap(new_thread, stacksize + guardsize); +# endif +#else +# ifdef USE_TLS + size_t stacksize = stack_addr - new_thread_bottom; +# else + size_t stacksize = (char *)(new_thread+1) - new_thread_bottom; +# endif + munmap(new_thread_bottom - guardsize, guardsize + stacksize); +#endif + } +#ifdef USE_TLS +# if TLS_DTV_AT_TP + new_thread = (pthread_descr) ((char *) new_thread + TLS_PRE_TCB_SIZE); +# endif + _dl_deallocate_tls (new_thread, true); +#endif + __pthread_handles[sseg].h_descr = NULL; + __pthread_handles[sseg].h_bottom = NULL; + __pthread_handles_num--; + return saved_errno; + } + /* Insert new thread in doubly linked list of active threads */ + new_thread->p_prevlive = __pthread_main_thread; + new_thread->p_nextlive = __pthread_main_thread->p_nextlive; + __pthread_main_thread->p_nextlive->p_prevlive = new_thread; + __pthread_main_thread->p_nextlive = new_thread; + /* Set pid field of the new thread, in case we get there before the + child starts. */ + new_thread->p_pid = pid; + return 0; +} + + +/* Try to free the resources of a thread when requested by pthread_join + or pthread_detach on a terminated thread. */ + +static void pthread_free(pthread_descr th) +{ + pthread_handle handle; + pthread_readlock_info *iter, *next; + + ASSERT(th->p_exited); + /* Make the handle invalid */ + handle = thread_handle(th->p_tid); + __pthread_lock(&handle->h_lock, NULL); + handle->h_descr = NULL; + handle->h_bottom = (char *)(-1L); + __pthread_unlock(&handle->h_lock); +#ifdef FREE_THREAD + FREE_THREAD(th, th->p_nr); +#endif + /* One fewer threads in __pthread_handles */ + __pthread_handles_num--; + + /* Destroy read lock list, and list of free read lock structures. + If the former is not empty, it means the thread exited while + holding read locks! */ + + for (iter = th->p_readlock_list; iter != NULL; iter = next) + { + next = iter->pr_next; + free(iter); + } + + for (iter = th->p_readlock_free; iter != NULL; iter = next) + { + next = iter->pr_next; + free(iter); + } + + /* If initial thread, nothing to free */ + if (!th->p_userstack) + { + size_t guardsize = th->p_guardsize; + /* Free the stack and thread descriptor area */ + char *guardaddr = th->p_guardaddr; +#ifdef _STACK_GROWS_UP +# ifdef USE_TLS + size_t stacksize = guardaddr - th->p_stackaddr; +# else + size_t stacksize = guardaddr - (char *)th; +# endif + guardaddr = (char *)th; +#else + /* Guardaddr is always set, even if guardsize is 0. This allows + us to compute everything else. */ +# ifdef USE_TLS + size_t stacksize = th->p_stackaddr - guardaddr - guardsize; +# else + size_t stacksize = (char *)(th+1) - guardaddr - guardsize; +# endif +# ifdef NEED_SEPARATE_REGISTER_STACK + /* Take account of the register stack, which is below guardaddr. */ + guardaddr -= stacksize; + stacksize *= 2; +# endif +#endif + /* Unmap the stack. */ + munmap(guardaddr, stacksize + guardsize); + + } + +#ifdef USE_TLS +# if TLS_DTV_AT_TP + th = (pthread_descr) ((char *) th + TLS_PRE_TCB_SIZE); +# endif + _dl_deallocate_tls (th, true); +#endif +} + +/* Handle threads that have exited */ + +static void pthread_exited(pid_t pid) +{ + pthread_descr th; + int detached; + /* Find thread with that pid */ + for (th = __pthread_main_thread->p_nextlive; + th != __pthread_main_thread; + th = th->p_nextlive) { + if (th->p_pid == pid) { + /* Remove thread from list of active threads */ + th->p_nextlive->p_prevlive = th->p_prevlive; + th->p_prevlive->p_nextlive = th->p_nextlive; + /* Mark thread as exited, and if detached, free its resources */ + __pthread_lock(th->p_lock, NULL); + th->p_exited = 1; + /* If we have to signal this event do it now. */ + if (th->p_report_events) + { + /* See whether TD_REAP is in any of the mask. */ + int idx = __td_eventword (TD_REAP); + uint32_t mask = __td_eventmask (TD_REAP); + + if ((mask & (__pthread_threads_events.event_bits[idx] + | th->p_eventbuf.eventmask.event_bits[idx])) != 0) + { + /* Yep, we have to signal the reapage. */ + th->p_eventbuf.eventnum = TD_REAP; + th->p_eventbuf.eventdata = th; + __pthread_last_event = th; + + /* Now call the function to signal the event. */ + __linuxthreads_reap_event(); + } + } + detached = th->p_detached; + __pthread_unlock(th->p_lock); + if (detached) + pthread_free(th); + break; + } + } + /* If all threads have exited and the main thread is pending on a + pthread_exit, wake up the main thread and terminate ourselves. */ + if (main_thread_exiting && + __pthread_main_thread->p_nextlive == __pthread_main_thread) { + restart(__pthread_main_thread); + /* Same logic as REQ_MAIN_THREAD_EXIT. */ + } +} + +static void pthread_reap_children(void) +{ + pid_t pid; + int status; + + while ((pid = waitpid_not_cancel(-1, &status, WNOHANG | __WCLONE)) > 0) { + pthread_exited(pid); + if (WIFSIGNALED(status)) { + /* If a thread died due to a signal, send the same signal to + all other threads, including the main thread. */ + pthread_kill_all_threads(WTERMSIG(status), 1); + _exit(0); + } + } +} + +/* Try to free the resources of a thread when requested by pthread_join + or pthread_detach on a terminated thread. */ + +static void pthread_handle_free(pthread_t th_id) +{ + pthread_handle handle = thread_handle(th_id); + pthread_descr th; + + __pthread_lock(&handle->h_lock, NULL); + if (nonexisting_handle(handle, th_id)) { + /* pthread_reap_children has deallocated the thread already, + nothing needs to be done */ + __pthread_unlock(&handle->h_lock); + return; + } + th = handle->h_descr; + if (th->p_exited) { + __pthread_unlock(&handle->h_lock); + pthread_free(th); + } else { + /* The Unix process of the thread is still running. + Mark the thread as detached so that the thread manager will + deallocate its resources when the Unix process exits. */ + th->p_detached = 1; + __pthread_unlock(&handle->h_lock); + } +} + +/* Send a signal to all running threads */ + +static void pthread_kill_all_threads(int sig, int main_thread_also) +{ + pthread_descr th; + for (th = __pthread_main_thread->p_nextlive; + th != __pthread_main_thread; + th = th->p_nextlive) { + kill(th->p_pid, sig); + } + if (main_thread_also) { + kill(__pthread_main_thread->p_pid, sig); + } +} + +static void pthread_for_each_thread(void *arg, + void (*fn)(void *, pthread_descr)) +{ + pthread_descr th; + + for (th = __pthread_main_thread->p_nextlive; + th != __pthread_main_thread; + th = th->p_nextlive) { + fn(arg, th); + } + + fn(arg, __pthread_main_thread); +} + +/* Process-wide exit() */ + +static void pthread_handle_exit(pthread_descr issuing_thread, int exitcode) +{ + pthread_descr th; + __pthread_exit_requested = 1; + __pthread_exit_code = exitcode; + /* A forced asynchronous cancellation follows. Make sure we won't + get stuck later in the main thread with a system lock being held + by one of the cancelled threads. Ideally one would use the same + code as in pthread_atfork(), but we can't distinguish system and + user handlers there. */ + __flockfilelist(); + /* Send the CANCEL signal to all running threads, including the main + thread, but excluding the thread from which the exit request originated + (that thread must complete the exit, e.g. calling atexit functions + and flushing stdio buffers). */ + for (th = issuing_thread->p_nextlive; + th != issuing_thread; + th = th->p_nextlive) { + kill(th->p_pid, __pthread_sig_cancel); + } + /* Now, wait for all these threads, so that they don't become zombies + and their times are properly added to the thread manager's times. */ + for (th = issuing_thread->p_nextlive; + th != issuing_thread; + th = th->p_nextlive) { + waitpid(th->p_pid, NULL, __WCLONE); + } + __fresetlockfiles(); + restart(issuing_thread); + _exit(0); +} + +/* Handler for __pthread_sig_cancel in thread manager thread */ + +void __pthread_manager_sighandler(int sig) +{ + int kick_manager = terminated_children == 0 && main_thread_exiting; + terminated_children = 1; + + /* If the main thread is terminating, kick the thread manager loop + each time some threads terminate. This eliminates a two second + shutdown delay caused by the thread manager sleeping in the + call to __poll(). Instead, the thread manager is kicked into + action, reaps the outstanding threads and resumes the main thread + so that it can complete the shutdown. */ + + if (kick_manager) { + struct pthread_request request; + request.req_thread = 0; + request.req_kind = REQ_KICK; + TEMP_FAILURE_RETRY(write_not_cancel(__pthread_manager_request, + (char *) &request, sizeof(request))); + } +} + +/* Adjust priority of thread manager so that it always run at a priority + higher than all threads */ + +void __pthread_manager_adjust_prio(int thread_prio) +{ + struct sched_param param; + + if (thread_prio <= manager_thread->p_priority) return; + param.sched_priority = + thread_prio < __sched_get_priority_max(SCHED_FIFO) + ? thread_prio + 1 : thread_prio; + __sched_setscheduler(manager_thread->p_pid, SCHED_FIFO, ¶m); + manager_thread->p_priority = thread_prio; +} |