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Diffstat (limited to 'libpthread/linuxthreads.old/manager.c')
| -rw-r--r-- | libpthread/linuxthreads.old/manager.c | 933 |
1 files changed, 933 insertions, 0 deletions
diff --git a/libpthread/linuxthreads.old/manager.c b/libpthread/linuxthreads.old/manager.c new file mode 100644 index 000000000..e4022f8ea --- /dev/null +++ b/libpthread/linuxthreads.old/manager.c @@ -0,0 +1,933 @@ +/* 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 <features.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 "pthread.h" +#include "internals.h" +#include "spinlock.h" +#include "restart.h" +#include "semaphore.h" +#include "debug.h" /* PDEBUG, added by StS */ + +#ifndef THREAD_STACK_OFFSET +#define THREAD_STACK_OFFSET 0 +#endif + +/* poll() is not supported in kernel <= 2.0, therefore is __NR_poll is + * not available, we assume an old Linux kernel is in use and we will + * use select() instead. */ +#include <sys/syscall.h> +#ifndef __NR_poll +# define USE_SELECT +#endif + +libpthread_hidden_proto(waitpid) +libpthread_hidden_proto(raise) + +/* Array of active threads. Entry 0 is reserved for the initial thread. */ +struct pthread_handle_struct __pthread_handles[PTHREAD_THREADS_MAX] = +{ { __LOCK_INITIALIZER, &__pthread_initial_thread, 0}, + { __LOCK_INITIALIZER, &__pthread_manager_thread, 0}, /* All NULLs */ }; + +/* For debugging purposes put the maximum number of threads in a variable. */ +const int __linuxthreads_pthread_threads_max = PTHREAD_THREADS_MAX; + +/* 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; + +/* 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; + +/* 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. */ + +static __inline__ pthread_descr thread_segment(int seg) +{ + return (pthread_descr)(THREAD_STACK_START_ADDRESS - (seg - 1) * STACK_SIZE) + - 1; +} + +/* Flag set in signal handler to record child termination */ + +static volatile int terminated_children = 0; + +/* Flag set when the initial thread is blocked on pthread_exit waiting + for all other threads to terminate */ + +static int main_thread_exiting = 0; + +/* Counter used to generate unique thread identifier. + Thread identifier is pthread_threads_counter + segment. */ + +static pthread_t pthread_threads_counter = 0; + +/* 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); + +/* The server thread managing requests for thread creation and termination */ + +int attribute_noreturn __pthread_manager(void *arg) +{ + int reqfd = (int) (long int) arg; +#ifdef USE_SELECT + struct timeval tv; + fd_set fd; +#else + struct pollfd ufd; +#endif + 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(&__pthread_manager_thread, 1); +#endif + /* Set the error variable. */ + __pthread_manager_thread.p_errnop = &__pthread_manager_thread.p_errno; + __pthread_manager_thread.p_h_errnop = &__pthread_manager_thread.p_h_errno; + +#ifdef __UCLIBC_HAS_XLOCALE__ + /* Initialize thread's locale to the global locale. */ + __pthread_manager_thread.locale = __global_locale; +#endif /* __UCLIBC_HAS_XLOCALE__ */ + + /* 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(reqfd, (char *)&request, + sizeof(request))); +#ifndef USE_SELECT + ufd.fd = reqfd; + ufd.events = POLLIN; +#endif + /* Enter server loop */ + while(1) { +#ifdef USE_SELECT + tv.tv_sec = 2; + tv.tv_usec = 0; + FD_ZERO (&fd); + FD_SET (reqfd, &fd); + n = select (reqfd + 1, &fd, NULL, NULL, &tv); +#else + PDEBUG("before poll\n"); + n = poll(&ufd, 1, 2000); + PDEBUG("after poll\n"); +#endif + /* 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 */ +#ifdef USE_SELECT + if (n == 1) +#else + if (n == 1 && (ufd.revents & POLLIN)) +#endif + { + + PDEBUG("before read\n"); + n = read(reqfd, (char *)&request, sizeof(request)); + PDEBUG("after read, n=%d\n", n); + switch(request.req_kind) { + case REQ_CREATE: + PDEBUG("got REQ_CREATE\n"); + 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); + PDEBUG("restarting %p\n", request.req_thread); + restart(request.req_thread); + break; + case REQ_FREE: + PDEBUG("got REQ_FREE\n"); + pthread_handle_free(request.req_args.free.thread_id); + break; + case REQ_PROCESS_EXIT: + PDEBUG("got REQ_PROCESS_EXIT from %p, exit code = %d\n", + request.req_thread, request.req_args.exit.code); + pthread_handle_exit(request.req_thread, + request.req_args.exit.code); + break; + case REQ_MAIN_THREAD_EXIT: + PDEBUG("got REQ_MAIN_THREAD_EXIT\n"); + 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: + PDEBUG("got REQ_POST\n"); + sem_post(request.req_args.post); + break; + case REQ_DEBUG: + PDEBUG("got REQ_DEBUG\n"); + /* 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) { + PDEBUG("about to call raise(__pthread_sig_debug)\n"); + raise(__pthread_sig_debug); + } + 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; + } + } + } +} + +int attribute_noreturn __pthread_manager_event(void *arg) +{ + /* If we have special thread_self processing, initialize it. */ +#ifdef INIT_THREAD_SELF + INIT_THREAD_SELF(&__pthread_manager_thread, 1); +#endif + + /* Get the lock the manager will free once all is correctly set up. */ + __pthread_lock (THREAD_GETMEM((&__pthread_manager_thread), p_lock), NULL); + /* Free it immediately. */ + __pthread_unlock (THREAD_GETMEM((&__pthread_manager_thread), p_lock)); + + __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; + /* Initialize special thread_self processing, if any. */ +#ifdef INIT_THREAD_SELF + INIT_THREAD_SELF(self, self->p_nr); +#endif + PDEBUG("\n"); + /* 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 (__pthread_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); + } + /* 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(__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); +} + +static int pthread_allocate_stack(const pthread_attr_t *attr, + pthread_descr default_new_thread, + int pagesize, + pthread_descr * out_new_thread, + char ** out_new_thread_bottom, + char ** out_guardaddr, + size_t * out_guardsize) +{ + pthread_descr new_thread; + char * new_thread_bottom; + char * guardaddr; + size_t stacksize, guardsize; + + if (attr != NULL && attr->__stackaddr_set) + { + /* The user provided a stack. */ + new_thread = (pthread_descr) ((long)(attr->__stackaddr) & -sizeof(void *)) - 1; + new_thread_bottom = (char *) attr->__stackaddr - attr->__stacksize; + guardaddr = NULL; + guardsize = 0; + __pthread_nonstandard_stacks = 1; +#ifndef __ARCH_USE_MMU__ + /* check the initial thread stack boundaries so they don't overlap */ + NOMMU_INITIAL_THREAD_BOUNDS((char *) new_thread, (char *) new_thread_bottom); + + PDEBUG("initial stack: bos=%p, tos=%p\n", __pthread_initial_thread_bos, + __pthread_initial_thread_tos); +#endif + } + else + { +#ifdef __ARCH_USE_MMU__ + stacksize = STACK_SIZE - pagesize; + if (attr != NULL) + stacksize = MIN(stacksize, roundup(attr->__stacksize, pagesize)); + /* Allocate space for stack and thread descriptor at default address */ + new_thread = default_new_thread; + new_thread_bottom = (char *) (new_thread + 1) - stacksize; + if (mmap((caddr_t)((char *)(new_thread + 1) - INITIAL_STACK_SIZE), + INITIAL_STACK_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED | MAP_GROWSDOWN, + -1, 0) == MAP_FAILED) + /* Bad luck, this segment is already mapped. */ + return -1; + /* We manage to get a stack. Now see whether we need a guard + and allocate it if necessary. Notice that the default + attributes (stack_size = STACK_SIZE - pagesize) do not need + a guard page, since the RLIMIT_STACK soft limit prevents stacks + from running into one another. */ + if (stacksize == (size_t) (STACK_SIZE - pagesize)) + { + /* We don't need a guard page. */ + guardaddr = NULL; + guardsize = 0; + } + else + { + /* Put a bad page at the bottom of the stack */ + guardsize = attr->__guardsize; + guardaddr = (void *)new_thread_bottom - guardsize; + if (mmap((caddr_t) guardaddr, guardsize, 0, MAP_FIXED, -1, 0) + == MAP_FAILED) + { + /* We don't make this an error. */ + guardaddr = NULL; + guardsize = 0; + } + } +#else + /* We cannot mmap to this huge chunk of stack space when we don't have + * an MMU. Pretend we are using a user provided stack even if there was + * none provided by the user. Thus, we get around the mmap and reservation + * of a huge stack segment. -StS */ + + stacksize = INITIAL_STACK_SIZE; + /* The user may want to use a non-default stacksize */ + if (attr != NULL) + { + stacksize = attr->__stacksize; + } + + /* malloc a stack - memory from the bottom up */ + if ((new_thread_bottom = malloc(stacksize)) == NULL) + { + /* bad luck, we cannot malloc any more */ + return -1 ; + } + PDEBUG("malloced chunk: base=%p, size=0x%04x\n", new_thread_bottom, stacksize); + + /* Set up the pointers. new_thread marks the TOP of the stack frame and + * the address of the pthread_descr struct at the same time. Therefore we + * must account for its size and fit it in the malloc()'ed block. The + * value of `new_thread' is then passed to clone() as the stack argument. + * + * ^ +------------------------+ + * | | pthread_descr struct | + * | +------------------------+ <- new_thread + * malloc block | | | + * | | thread stack | + * | | | + * v +------------------------+ <- new_thread_bottom + * + * Note: The calculated value of new_thread must be word aligned otherwise + * the kernel chokes on a non-aligned stack frame. Choose the lower + * available word boundary. + */ + new_thread = ((pthread_descr) ((int)(new_thread_bottom + stacksize) & -sizeof(void*))) - 1; + guardaddr = NULL; + guardsize = 0; + + PDEBUG("thread stack: bos=%p, tos=%p\n", new_thread_bottom, new_thread); + + /* check the initial thread stack boundaries so they don't overlap */ + NOMMU_INITIAL_THREAD_BOUNDS((char *) new_thread, (char *) new_thread_bottom); + + PDEBUG("initial stack: bos=%p, tos=%p\n", __pthread_initial_thread_bos, + __pthread_initial_thread_tos); + + /* on non-MMU systems we always have non-standard stack frames */ + __pthread_nonstandard_stacks = 1; + +#endif /* __ARCH_USE_MMU__ */ + } + + /* Clear the thread data structure. */ + memset (new_thread, '\0', sizeof (*new_thread)); + *out_new_thread = new_thread; + *out_new_thread_bottom = new_thread_bottom; + *out_guardaddr = guardaddr; + *out_guardsize = guardsize; + 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 * new_thread_bottom; + char * new_thread_top; + pthread_t new_thread_id; + char *guardaddr = NULL; + size_t guardsize = 0; + int pagesize = getpagesize(); + int saved_errno = 0; + + /* 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) + return EAGAIN; + if (__pthread_handles[sseg].h_descr != NULL) + continue; + if (pthread_allocate_stack(attr, thread_segment(sseg), pagesize, + &new_thread, &new_thread_bottom, + &guardaddr, &guardsize) == 0) + break; +#ifndef __ARCH_USE_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. */ + 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; + new_thread->p_errnop = &new_thread->p_errno; + new_thread->p_h_errnop = &new_thread->p_h_errno; +#ifdef __UCLIBC_HAS_XLOCALE__ + /* Initialize thread's locale to the global locale. */ + new_thread->locale = __global_locale; +#endif /* __UCLIBC_HAS_XLOCALE__ */ + new_thread->p_guardaddr = guardaddr; + new_thread->p_guardsize = guardsize; + new_thread->p_self = new_thread; + new_thread->p_nr = sseg; + /* 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; + /* 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. */ + new_thread_top = ((char *)new_thread - THREAD_STACK_OFFSET); + + /* ******************************************************** */ + /* This code was moved from below to cope with running threads + * on uClinux systems. See comment below... + * 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; + /* ********************************************************* */ + + 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 m = __td_eventmask (TD_CREATE); + + if ((m & (__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 __ia64__ + pid = __clone2(pthread_start_thread_event, new_thread_top, + new_thread_top - new_thread_bottom, + CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | + __pthread_sig_cancel, new_thread); +#else + pid = clone(pthread_start_thread_event, new_thread_top, + 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) + { + PDEBUG("cloning new_thread = %p\n", new_thread); +#ifdef __ia64__ + pid = __clone2(pthread_start_thread, new_thread_top, + new_thread_top - new_thread_bottom, + CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | + __pthread_sig_cancel, new_thread); +#else + pid = clone(pthread_start_thread, new_thread_top, + CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | + __pthread_sig_cancel, new_thread); +#endif + saved_errno = errno; + } + /* Check if cloning succeeded */ + if (pid == -1) { + /******************************************************** + * Code inserted to remove the thread from our list of active + * threads in case of failure (needed to cope with uClinux), + * See comment below. */ + new_thread->p_nextlive->p_prevlive = new_thread->p_prevlive; + new_thread->p_prevlive->p_nextlive = new_thread->p_nextlive; + /********************************************************/ + + /* Free the stack if we allocated it */ + if (attr == NULL || !attr->__stackaddr_set) + { +#ifdef __ARCH_USE_MMU__ + if (new_thread->p_guardsize != 0) + munmap(new_thread->p_guardaddr, new_thread->p_guardsize); + munmap((caddr_t)((char *)(new_thread+1) - INITIAL_STACK_SIZE), + INITIAL_STACK_SIZE); +#else + free(new_thread_bottom); +#endif /* __ARCH_USE_MMU__ */ + } + __pthread_handles[sseg].h_descr = NULL; + __pthread_handles[sseg].h_bottom = NULL; + __pthread_handles_num--; + return saved_errno; + } + PDEBUG("new thread pid = %d\n", pid); + +#if 0 + /* *********************************************************** + This code has been moved before the call to clone(). In uClinux, + the use of wait on a semaphore is dependant upon that the child so + the child must be in the active threads list. This list is used in + pthread_find_self() to get the pthread_descr of self. So, if the + child calls sem_wait before this code is executed , it will hang + forever and initial_thread will instead be posted by a sem_post + call. */ + + /* 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; + /************************************************************/ +#endif + + /* Set pid field of the new thread, in case we get there before the + child starts. */ + new_thread->p_pid = pid; + /* We're all set */ + *thread = new_thread_id; + 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; +#ifndef __ARCH_USE_MMU__ + char *h_bottom_save; +#endif + + /* Make the handle invalid */ + handle = thread_handle(th->p_tid); + __pthread_lock(&handle->h_lock, NULL); +#ifndef __ARCH_USE_MMU__ + h_bottom_save = handle->h_bottom; +#endif + handle->h_descr = NULL; + handle->h_bottom = (char *)(-1L); + __pthread_unlock(&handle->h_lock); +#ifdef FREE_THREAD_SELF + FREE_THREAD_SELF(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 == &__pthread_initial_thread) return; + if (!th->p_userstack) + { +#ifdef __ARCH_USE_MMU__ + /* Free the stack and thread descriptor area */ + if (th->p_guardsize != 0) + munmap(th->p_guardaddr, th->p_guardsize); + munmap((caddr_t) ((char *)(th+1) - STACK_SIZE), STACK_SIZE); +#else + /* For non-MMU systems we always malloc the stack, so free it here. -StS */ + free(h_bottom_save); +#endif /* __ARCH_USE_MMU__ */ + } +} + +/* 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; + PDEBUG("\n"); + + while ((pid = waitpid(-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 (invalid_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); + } +} + +/* 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; + /* 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); + } + restart(issuing_thread); + _exit(0); +} + +/* Handler for __pthread_sig_cancel in thread manager thread */ + +void __pthread_manager_sighandler(int sig attribute_unused) +{ + 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(__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 <= __pthread_manager_thread.p_priority) return; + param.sched_priority = + thread_prio < sched_get_priority_max(SCHED_FIFO) + ? thread_prio + 1 : thread_prio; + sched_setscheduler(__pthread_manager_thread.p_pid, SCHED_FIFO, ¶m); + __pthread_manager_thread.p_priority = thread_prio; +} |