diff options
Diffstat (limited to 'libpthread/linuxthreads/pthread.c')
| -rw-r--r-- | libpthread/linuxthreads/pthread.c | 876 |
1 files changed, 876 insertions, 0 deletions
diff --git a/libpthread/linuxthreads/pthread.c b/libpthread/linuxthreads/pthread.c new file mode 100644 index 000000000..51d600a18 --- /dev/null +++ b/libpthread/linuxthreads/pthread.c @@ -0,0 +1,876 @@ +/* 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. */ + +/* Thread creation, initialization, and basic low-level routines */ + +#define __FORCE_GLIBC +#include <features.h> +#include <errno.h> +#include <netdb.h> /* for h_errno */ +#include <stddef.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <fcntl.h> +#include <sys/wait.h> +#include <sys/resource.h> +#include "pthread.h" +#include "internals.h" +#include "spinlock.h" +#include "restart.h" +#include "debug.h" /* added to linuxthreads -StS */ + +/* mods for uClibc: getpwd and getpagesize are the syscalls */ +#define __getpid getpid +#define __getpagesize getpagesize +/* mods for uClibc: __libc_sigaction is not in any standard headers */ +#include <signal.h> +extern int __libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact); + + +/* These variables are used by the setup code. */ +extern int _errno; +extern int _h_errno; + + +/* Descriptor of the initial thread */ + +struct _pthread_descr_struct __pthread_initial_thread = { + &__pthread_initial_thread, /* pthread_descr p_nextlive */ + &__pthread_initial_thread, /* pthread_descr p_prevlive */ + NULL, /* pthread_descr p_nextwaiting */ + NULL, /* pthread_descr p_nextlock */ + PTHREAD_THREADS_MAX, /* pthread_t p_tid */ + 0, /* int p_pid */ + 0, /* int p_priority */ + &__pthread_handles[0].h_lock, /* struct _pthread_fastlock * p_lock */ + 0, /* int p_signal */ + NULL, /* sigjmp_buf * p_signal_buf */ + NULL, /* sigjmp_buf * p_cancel_buf */ + 0, /* char p_terminated */ + 0, /* char p_detached */ + 0, /* char p_exited */ + NULL, /* void * p_retval */ + 0, /* int p_retval */ + NULL, /* pthread_descr p_joining */ + NULL, /* struct _pthread_cleanup_buffer * p_cleanup */ + 0, /* char p_cancelstate */ + 0, /* char p_canceltype */ + 0, /* char p_canceled */ + &_errno, /* int *p_errnop */ + 0, /* int p_errno */ + &_h_errno, /* int *p_h_errnop */ + 0, /* int p_h_errno */ + NULL, /* char * p_in_sighandler */ + 0, /* char p_sigwaiting */ + PTHREAD_START_ARGS_INITIALIZER, /* struct pthread_start_args p_start_args */ + {NULL}, /* void ** p_specific[PTHREAD_KEY_1STLEVEL_SIZE] */ + {NULL}, /* void * p_libc_specific[_LIBC_TSD_KEY_N] */ + 0, /* int p_userstack */ + NULL, /* void * p_guardaddr */ + 0, /* size_t p_guardsize */ + &__pthread_initial_thread, /* pthread_descr p_self */ + 0, /* Always index 0 */ + 0, /* int p_report_events */ + {{{0, }}, 0, NULL}, /* td_eventbuf_t p_eventbuf */ + ATOMIC_INITIALIZER, /* struct pthread_atomic p_resume_count */ + 0, /* char p_woken_by_cancel */ + NULL, /* struct pthread_extricate_if *p_extricate */ + NULL, /* pthread_readlock_info *p_readlock_list; */ + NULL, /* pthread_readlock_info *p_readlock_free; */ + 0 /* int p_untracked_readlock_count; */ +}; + +/* Descriptor of the manager thread; none of this is used but the error + variables, the p_pid and p_priority fields, + and the address for identification. */ + +struct _pthread_descr_struct __pthread_manager_thread = { + NULL, /* pthread_descr p_nextlive */ + NULL, /* pthread_descr p_prevlive */ + NULL, /* pthread_descr p_nextwaiting */ + NULL, /* pthread_descr p_nextlock */ + 0, /* int p_tid */ + 0, /* int p_pid */ + 0, /* int p_priority */ + &__pthread_handles[1].h_lock, /* struct _pthread_fastlock * p_lock */ + 0, /* int p_signal */ + NULL, /* sigjmp_buf * p_signal_buf */ + NULL, /* sigjmp_buf * p_cancel_buf */ + 0, /* char p_terminated */ + 0, /* char p_detached */ + 0, /* char p_exited */ + NULL, /* void * p_retval */ + 0, /* int p_retval */ + NULL, /* pthread_descr p_joining */ + NULL, /* struct _pthread_cleanup_buffer * p_cleanup */ + 0, /* char p_cancelstate */ + 0, /* char p_canceltype */ + 0, /* char p_canceled */ + &__pthread_manager_thread.p_errno, /* int *p_errnop */ + 0, /* int p_errno */ + NULL, /* int *p_h_errnop */ + 0, /* int p_h_errno */ + NULL, /* char * p_in_sighandler */ + 0, /* char p_sigwaiting */ + PTHREAD_START_ARGS_INITIALIZER, /* struct pthread_start_args p_start_args */ + {NULL}, /* void ** p_specific[PTHREAD_KEY_1STLEVEL_SIZE] */ + {NULL}, /* void * p_libc_specific[_LIBC_TSD_KEY_N] */ + 0, /* int p_userstack */ + NULL, /* void * p_guardaddr */ + 0, /* size_t p_guardsize */ + &__pthread_manager_thread, /* pthread_descr p_self */ + 1, /* Always index 1 */ + 0, /* int p_report_events */ + {{{0, }}, 0, NULL}, /* td_eventbuf_t p_eventbuf */ + ATOMIC_INITIALIZER, /* struct pthread_atomic p_resume_count */ + 0, /* char p_woken_by_cancel */ + NULL, /* struct pthread_extricate_if *p_extricate */ + NULL, /* pthread_readlock_info *p_readlock_list; */ + NULL, /* pthread_readlock_info *p_readlock_free; */ + 0 /* int p_untracked_readlock_count; */ +}; + +/* Pointer to the main thread (the father of the thread manager thread) */ +/* Originally, this is the initial thread, but this changes after fork() */ + +pthread_descr __pthread_main_thread = &__pthread_initial_thread; + +/* Limit between the stack of the initial thread (above) and the + stacks of other threads (below). Aligned on a STACK_SIZE boundary. */ + +char *__pthread_initial_thread_bos = NULL; + +/* For non-MMU systems also remember to stack top of the initial thread. + * This is adapted when other stacks are malloc'ed since we don't know + * the bounds a-priori. -StS */ + +#ifndef __UCLIBC_HAS_MMU__ +char *__pthread_initial_thread_tos = NULL; +#endif /* __UCLIBC_HAS_MMU__ */ + +/* File descriptor for sending requests to the thread manager. */ +/* Initially -1, meaning that the thread manager is not running. */ + +int __pthread_manager_request = -1; + +/* Other end of the pipe for sending requests to the thread manager. */ + +int __pthread_manager_reader; + +/* Limits of the thread manager stack */ + +char *__pthread_manager_thread_bos = NULL; +char *__pthread_manager_thread_tos = NULL; + +/* For process-wide exit() */ + +int __pthread_exit_requested = 0; +int __pthread_exit_code = 0; + +/* Pointers that select new or old suspend/resume functions + based on availability of rt signals. */ + +void (*__pthread_restart)(pthread_descr) = __pthread_restart_old; +void (*__pthread_suspend)(pthread_descr) = __pthread_suspend_old; + +/* Communicate relevant LinuxThreads constants to gdb */ + +const int __pthread_threads_max = PTHREAD_THREADS_MAX; +const int __pthread_sizeof_handle = sizeof(struct pthread_handle_struct); +const int __pthread_offsetof_descr = offsetof(struct pthread_handle_struct, + h_descr); +const int __pthread_offsetof_pid = offsetof(struct _pthread_descr_struct, + p_pid); + +/* Forward declarations */ + +static void pthread_exit_process(int retcode, void *arg); +#ifndef __i386__ +static void pthread_handle_sigcancel(int sig); +static void pthread_handle_sigrestart(int sig); +#else +static void pthread_handle_sigcancel(int sig, struct sigcontext ctx); +static void pthread_handle_sigrestart(int sig, struct sigcontext ctx); +#endif +static void pthread_handle_sigdebug(int sig); + +/* Signal numbers used for the communication. + In these variables we keep track of the used variables. If the + platform does not support any real-time signals we will define the + values to some unreasonable value which will signal failing of all + the functions below. */ +#ifndef __SIGRTMIN +static int current_rtmin = -1; +static int current_rtmax = -1; +int __pthread_sig_restart = SIGUSR1; +int __pthread_sig_cancel = SIGUSR2; +int __pthread_sig_debug = 0; +#else +static int current_rtmin; +static int current_rtmax; + +#if __SIGRTMAX - __SIGRTMIN >= 3 +int __pthread_sig_restart = __SIGRTMIN; +int __pthread_sig_cancel = __SIGRTMIN + 1; +int __pthread_sig_debug = __SIGRTMIN + 2; +#else +int __pthread_sig_restart = SIGUSR1; +int __pthread_sig_cancel = SIGUSR2; +int __pthread_sig_debug = 0; +#endif + +static int rtsigs_initialized; + +#include "testrtsig.h" + +static void +init_rtsigs (void) +{ + if (!kernel_has_rtsig ()) + { + current_rtmin = -1; + current_rtmax = -1; +#if __SIGRTMAX - __SIGRTMIN >= 3 + __pthread_sig_restart = SIGUSR1; + __pthread_sig_cancel = SIGUSR2; + __pthread_sig_debug = 0; +#endif +PDEBUG("no rt-sigs, sig_restart=%d, sig_cancel=%d.\n", __pthread_sig_restart, __pthread_sig_cancel ); + __pthread_init_condvar(0); + } + else + { +#if __SIGRTMAX - __SIGRTMIN >= 3 + current_rtmin = __SIGRTMIN + 3; + __pthread_restart = __pthread_restart_new; + __pthread_suspend = __pthread_wait_for_restart_signal; + __pthread_init_condvar(1); +#else + current_rtmin = __SIGRTMIN; + __pthread_init_condvar(0); +#endif + + current_rtmax = __SIGRTMAX; +PDEBUG("have rt-sigs, rtmin = %d, rtmax = %d.\n", current_rtmin, current_rtmax); + } + + rtsigs_initialized = 1; +} +#endif + +/* Return number of available real-time signal with highest priority. */ +int +__libc_current_sigrtmin (void) +{ +#ifdef __SIGRTMIN + if (!rtsigs_initialized) + init_rtsigs (); +#endif + return current_rtmin; +} + +/* Return number of available real-time signal with lowest priority. */ +int +__libc_current_sigrtmax (void) +{ +#ifdef __SIGRTMIN + if (!rtsigs_initialized) + init_rtsigs (); +#endif + return current_rtmax; +} + +/* Allocate real-time signal with highest/lowest available + priority. Please note that we don't use a lock since we assume + this function to be called at program start. */ +int +__libc_allocate_rtsig (int high) +{ +#ifndef __SIGRTMIN + return -1; +#else + if (!rtsigs_initialized) + init_rtsigs (); + if (current_rtmin == -1 || current_rtmin > current_rtmax) + /* We don't have anymore signal available. */ + return -1; + + return high ? current_rtmin++ : current_rtmax--; +#endif +} + +/* Initialize the pthread library. + Initialization is split in two functions: + - a constructor function that blocks the __pthread_sig_restart signal + (must do this very early, since the program could capture the signal + mask with e.g. sigsetjmp before creating the first thread); + - a regular function called from pthread_create when needed. */ + +static void pthread_initialize(void) __attribute__((constructor)); + +static void pthread_initialize(void) +{ + struct sigaction sa; + sigset_t mask; + struct rlimit limit; + int max_stack; + + /* If already done (e.g. by a constructor called earlier!), bail out */ + if (__pthread_initial_thread_bos != NULL) return; +#ifdef TEST_FOR_COMPARE_AND_SWAP + /* Test if compare-and-swap is available */ + __pthread_has_cas = compare_and_swap_is_available(); +#endif + /* For the initial stack, reserve at least STACK_SIZE bytes of stack + below the current stack address, and align that on a + STACK_SIZE boundary. */ + __pthread_initial_thread_bos = + (char *)(((long)CURRENT_STACK_FRAME - 2 * STACK_SIZE) & ~(STACK_SIZE - 1)); + /* Update the descriptor for the initial thread. */ + __pthread_initial_thread.p_pid = __getpid(); + /* If we have special thread_self processing, initialize that for the + main thread now. */ +#ifdef INIT_THREAD_SELF + INIT_THREAD_SELF(&__pthread_initial_thread, 0); +#endif + /* The errno/h_errno variable of the main thread are the global ones. */ + __pthread_initial_thread.p_errnop = &_errno; + __pthread_initial_thread.p_h_errnop = &_h_errno; + /* Play with the stack size limit to make sure that no stack ever grows + beyond STACK_SIZE minus two pages (one page for the thread descriptor + immediately beyond, and one page to act as a guard page). */ + +#ifdef __UCLIBC_HAS_MMU__ + /* We cannot allocate a huge chunk of memory to mmap all thread stacks later + * on a non-MMU system. Thus, we don't need the rlimit either. -StS */ + getrlimit(RLIMIT_STACK, &limit); + max_stack = STACK_SIZE - 2 * __getpagesize(); + if (limit.rlim_cur > max_stack) { + limit.rlim_cur = max_stack; + setrlimit(RLIMIT_STACK, &limit); + } +#else + /* For non-MMU assume __pthread_initial_thread_tos at upper page boundary, and + * __pthread_initial_thread_bos at address 0. These bounds are refined as we + * malloc other stack frames such that they don't overlap. -StS + */ + __pthread_initial_thread_tos = + (char *)(((long)CURRENT_STACK_FRAME + __getpagesize()) & ~(__getpagesize() - 1)); + __pthread_initial_thread_bos = (char *) 1; /* set it non-zero so we know we have been here */ + PDEBUG("initial thread stack bounds: bos=%p, tos=%p\n", + __pthread_initial_thread_bos, __pthread_initial_thread_tos); +#endif /* __UCLIBC_HAS_MMU__ */ + +#ifdef __SIGRTMIN + /* Initialize real-time signals. */ + init_rtsigs (); +#endif + /* Setup signal handlers for the initial thread. + Since signal handlers are shared between threads, these settings + will be inherited by all other threads. */ +#ifndef __i386__ + sa.sa_handler = pthread_handle_sigrestart; +#else + sa.sa_handler = (__sighandler_t) pthread_handle_sigrestart; +#endif + sigemptyset(&sa.sa_mask); + sa.sa_flags = 0; + __libc_sigaction(__pthread_sig_restart, &sa, NULL); +#ifndef __i386__ + sa.sa_handler = pthread_handle_sigcancel; +#else + sa.sa_handler = (__sighandler_t) pthread_handle_sigcancel; +#endif + sa.sa_flags = 0; + __libc_sigaction(__pthread_sig_cancel, &sa, NULL); + if (__pthread_sig_debug > 0) { + sa.sa_handler = pthread_handle_sigdebug; + sigemptyset(&sa.sa_mask); + sa.sa_flags = 0; + __libc_sigaction(__pthread_sig_debug, &sa, NULL); + } + /* Initially, block __pthread_sig_restart. Will be unblocked on demand. */ + sigemptyset(&mask); + sigaddset(&mask, __pthread_sig_restart); +PDEBUG("block mask = %x\n", mask); + sigprocmask(SIG_BLOCK, &mask, NULL); + /* Register an exit function to kill all other threads. */ + /* Do it early so that user-registered atexit functions are called + before pthread_exit_process. */ + on_exit(pthread_exit_process, NULL); +} + +void __pthread_initialize(void) +{ + pthread_initialize(); +} + +int __pthread_initialize_manager(void) +{ + int manager_pipe[2]; + int pid; + struct pthread_request request; + + /* If basic initialization not done yet (e.g. we're called from a + constructor run before our constructor), do it now */ + if (__pthread_initial_thread_bos == NULL) pthread_initialize(); + /* Setup stack for thread manager */ + __pthread_manager_thread_bos = malloc(THREAD_MANAGER_STACK_SIZE); + if (__pthread_manager_thread_bos == NULL) return -1; + __pthread_manager_thread_tos = + __pthread_manager_thread_bos + THREAD_MANAGER_STACK_SIZE; + + /* On non-MMU systems we make sure that the initial thread bounds don't overlap + * with the manager stack frame */ + NOMMU_INITIAL_THREAD_BOUNDS(__pthread_manager_thread_tos,__pthread_manager_thread_bos); + PDEBUG("manager stack: size=%d, bos=%p, tos=%p\n", THREAD_MANAGER_STACK_SIZE, + __pthread_manager_thread_bos, __pthread_manager_thread_tos); + PDEBUG("initial stack: estimate bos=%p, tos=%p\n", + __pthread_initial_thread_bos, __pthread_initial_thread_tos); + + /* Setup pipe to communicate with thread manager */ + if (pipe(manager_pipe) == -1) { + free(__pthread_manager_thread_bos); + return -1; + } + /* Start the thread manager */ + pid = 0; + if (__pthread_initial_thread.p_report_events) + { + /* It's a bit more complicated. We have to report the creation of + the manager thread. */ + int idx = __td_eventword (TD_CREATE); + uint32_t mask = __td_eventmask (TD_CREATE); + + if ((mask & (__pthread_threads_events.event_bits[idx] + | __pthread_initial_thread.p_eventbuf.eventmask.event_bits[idx])) + != 0) + { + pid = clone(__pthread_manager_event, + (void **) __pthread_manager_thread_tos, + CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND, + (void *)(long)manager_pipe[0]); + + 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. */ + __pthread_manager_thread.p_eventbuf.eventdata = + &__pthread_manager_thread; + __pthread_manager_thread.p_eventbuf.eventnum = TD_CREATE; + __pthread_last_event = &__pthread_manager_thread; + __pthread_manager_thread.p_tid = 2* PTHREAD_THREADS_MAX + 1; + __pthread_manager_thread.p_pid = pid; + + /* Now call the function which signals the event. */ + __linuxthreads_create_event (); + + /* Now restart the thread. */ + __pthread_unlock(__pthread_manager_thread.p_lock); + } + } + } + + if (pid == 0) { + pid = clone(__pthread_manager, (void **) __pthread_manager_thread_tos, + CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND, + (void *)(long)manager_pipe[0]); + } + if (pid == -1) { + free(__pthread_manager_thread_bos); + __libc_close(manager_pipe[0]); + __libc_close(manager_pipe[1]); + return -1; + } + __pthread_manager_request = manager_pipe[1]; /* writing end */ + __pthread_manager_reader = manager_pipe[0]; /* reading end */ + __pthread_manager_thread.p_tid = 2* PTHREAD_THREADS_MAX + 1; + __pthread_manager_thread.p_pid = pid; + /* Make gdb aware of new thread manager */ + if (__pthread_threads_debug && __pthread_sig_debug > 0) + { + raise(__pthread_sig_debug); + /* We suspend ourself and gdb will wake us up when it is + ready to handle us. */ + __pthread_wait_for_restart_signal(thread_self()); + } + /* Synchronize debugging of the thread manager */ +PDEBUG("send REQ_DEBUG to manager thread\n"); + request.req_kind = REQ_DEBUG; + __libc_write(__pthread_manager_request, (char *) &request, sizeof(request)); + return 0; +} + +/* Thread creation */ + +int pthread_create(pthread_t *thread, const pthread_attr_t *attr, + void * (*start_routine)(void *), void *arg) +{ + pthread_descr self = thread_self(); + struct pthread_request request; + if (__pthread_manager_request < 0) { + if (__pthread_initialize_manager() < 0) return EAGAIN; + } + request.req_thread = self; + request.req_kind = REQ_CREATE; + request.req_args.create.attr = attr; + request.req_args.create.fn = start_routine; + request.req_args.create.arg = arg; + sigprocmask(SIG_SETMASK, (const sigset_t *) NULL, + &request.req_args.create.mask); + PDEBUG("write REQ_CREATE to manager thread\n"); + __libc_write(__pthread_manager_request, (char *) &request, sizeof(request)); +PDEBUG("before suspend(self)\n"); + suspend(self); +PDEBUG("after suspend(self)\n"); + if (THREAD_GETMEM(self, p_retcode) == 0) + *thread = (pthread_t) THREAD_GETMEM(self, p_retval); + return THREAD_GETMEM(self, p_retcode); +} + +/* Simple operations on thread identifiers */ + +pthread_t pthread_self(void) +{ + pthread_descr self = thread_self(); + return THREAD_GETMEM(self, p_tid); +} + +int pthread_equal(pthread_t thread1, pthread_t thread2) +{ + return thread1 == thread2; +} + +/* Helper function for thread_self in the case of user-provided stacks */ + +#ifndef THREAD_SELF + +pthread_descr __pthread_find_self() +{ + char * sp = CURRENT_STACK_FRAME; + pthread_handle h; + + /* __pthread_handles[0] is the initial thread, __pthread_handles[1] is + the manager threads handled specially in thread_self(), so start at 2 */ + h = __pthread_handles + 2; + while (! (sp <= (char *) h->h_descr && sp >= h->h_bottom)) h++; + +#ifdef DEBUG_PT + if (h->h_descr == NULL) { + printf("*** "__FUNCTION__" ERROR descriptor is NULL!!!!! ***\n\n"); + _exit(1); + } +#endif + + return h->h_descr; +} + +#endif + +/* Thread scheduling */ + +int pthread_setschedparam(pthread_t thread, int policy, + const struct sched_param *param) +{ + pthread_handle handle = thread_handle(thread); + pthread_descr th; + + __pthread_lock(&handle->h_lock, NULL); + if (invalid_handle(handle, thread)) { + __pthread_unlock(&handle->h_lock); + return ESRCH; + } + th = handle->h_descr; + if (sched_setscheduler(th->p_pid, policy, param) == -1) { + __pthread_unlock(&handle->h_lock); + return errno; + } + th->p_priority = policy == SCHED_OTHER ? 0 : param->sched_priority; + __pthread_unlock(&handle->h_lock); + if (__pthread_manager_request >= 0) + __pthread_manager_adjust_prio(th->p_priority); + return 0; +} + +int pthread_getschedparam(pthread_t thread, int *policy, + struct sched_param *param) +{ + pthread_handle handle = thread_handle(thread); + int pid, pol; + + __pthread_lock(&handle->h_lock, NULL); + if (invalid_handle(handle, thread)) { + __pthread_unlock(&handle->h_lock); + return ESRCH; + } + pid = handle->h_descr->p_pid; + __pthread_unlock(&handle->h_lock); + pol = sched_getscheduler(pid); + if (pol == -1) return errno; + if (sched_getparam(pid, param) == -1) return errno; + *policy = pol; + return 0; +} + +/* Process-wide exit() request */ + +static void pthread_exit_process(int retcode, void *arg) +{ + struct pthread_request request; + pthread_descr self = thread_self(); + + if (__pthread_manager_request >= 0) { + request.req_thread = self; + request.req_kind = REQ_PROCESS_EXIT; + request.req_args.exit.code = retcode; + __libc_write(__pthread_manager_request, + (char *) &request, sizeof(request)); + suspend(self); + /* Main thread should accumulate times for thread manager and its + children, so that timings for main thread account for all threads. */ + if (self == __pthread_main_thread) + waitpid(__pthread_manager_thread.p_pid, NULL, __WCLONE); + } +} + +/* The handler for the RESTART signal just records the signal received + in the thread descriptor, and optionally performs a siglongjmp + (for pthread_cond_timedwait). */ + +#ifndef __i386__ +static void pthread_handle_sigrestart(int sig) +{ + pthread_descr self = thread_self(); + PDEBUG("got called in non-i386 mode for %u\n", self); +#else +static void pthread_handle_sigrestart(int sig, struct sigcontext ctx) +{ + pthread_descr self; + asm volatile ("movw %w0,%%gs" : : "r" (ctx.gs)); + self = thread_self(); + PDEBUG("got called in i386-mode for %u\n", self); +#endif + THREAD_SETMEM(self, p_signal, sig); + if (THREAD_GETMEM(self, p_signal_jmp) != NULL) + siglongjmp(*THREAD_GETMEM(self, p_signal_jmp), 1); +} + +/* The handler for the CANCEL signal checks for cancellation + (in asynchronous mode), for process-wide exit and exec requests. + For the thread manager thread, redirect the signal to + __pthread_manager_sighandler. */ + +#ifndef __i386__ +static void pthread_handle_sigcancel(int sig) +{ + pthread_descr self = thread_self(); + sigjmp_buf * jmpbuf; +#else +static void pthread_handle_sigcancel(int sig, struct sigcontext ctx) +{ + pthread_descr self; + sigjmp_buf * jmpbuf; + asm volatile ("movw %w0,%%gs" : : "r" (ctx.gs)); + self = thread_self(); +#endif + + if (self == &__pthread_manager_thread) + { + __pthread_manager_sighandler(sig); + return; + } + if (__pthread_exit_requested) { + /* Main thread should accumulate times for thread manager and its + children, so that timings for main thread account for all threads. */ + if (self == __pthread_main_thread) + waitpid(__pthread_manager_thread.p_pid, NULL, __WCLONE); + _exit(__pthread_exit_code); + } + if (THREAD_GETMEM(self, p_canceled) + && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE) { + if (THREAD_GETMEM(self, p_canceltype) == PTHREAD_CANCEL_ASYNCHRONOUS) + pthread_exit(PTHREAD_CANCELED); + jmpbuf = THREAD_GETMEM(self, p_cancel_jmp); + if (jmpbuf != NULL) { + THREAD_SETMEM(self, p_cancel_jmp, NULL); + siglongjmp(*jmpbuf, 1); + } + } +} + +/* Handler for the DEBUG signal. + The debugging strategy is as follows: + On reception of a REQ_DEBUG request (sent by new threads created to + the thread manager under debugging mode), the thread manager throws + __pthread_sig_debug to itself. The debugger (if active) intercepts + this signal, takes into account new threads and continue execution + of the thread manager by propagating the signal because it doesn't + know what it is specifically done for. In the current implementation, + the thread manager simply discards it. */ + +static void pthread_handle_sigdebug(int sig) +{ + /* Nothing */ +} + +/* Reset the state of the thread machinery after a fork(). + Close the pipe used for requests and set the main thread to the forked + thread. + Notice that we can't free the stack segments, as the forked thread + may hold pointers into them. */ + +void __pthread_reset_main_thread() +{ + pthread_descr self = thread_self(); + + if (__pthread_manager_request != -1) { + /* Free the thread manager stack */ + free(__pthread_manager_thread_bos); + __pthread_manager_thread_bos = __pthread_manager_thread_tos = NULL; + /* Close the two ends of the pipe */ + __libc_close(__pthread_manager_request); + __libc_close(__pthread_manager_reader); + __pthread_manager_request = __pthread_manager_reader = -1; + } + + /* Update the pid of the main thread */ + THREAD_SETMEM(self, p_pid, __getpid()); + /* Make the forked thread the main thread */ + __pthread_main_thread = self; + THREAD_SETMEM(self, p_nextlive, self); + THREAD_SETMEM(self, p_prevlive, self); + /* Now this thread modifies the global variables. */ + THREAD_SETMEM(self, p_errnop, &_errno); + THREAD_SETMEM(self, p_h_errnop, &_h_errno); +} + +/* Process-wide exec() request */ + +void __pthread_kill_other_threads_np(void) +{ + struct sigaction sa; + /* Terminate all other threads and thread manager */ + pthread_exit_process(0, NULL); + /* Make current thread the main thread in case the calling thread + changes its mind, does not exec(), and creates new threads instead. */ + __pthread_reset_main_thread(); + /* Reset the signal handlers behaviour for the signals the + implementation uses since this would be passed to the new + process. */ + sigemptyset(&sa.sa_mask); + sa.sa_flags = 0; + sa.sa_handler = SIG_DFL; + __libc_sigaction(__pthread_sig_restart, &sa, NULL); + __libc_sigaction(__pthread_sig_cancel, &sa, NULL); + if (__pthread_sig_debug > 0) + __libc_sigaction(__pthread_sig_debug, &sa, NULL); +} +weak_alias (__pthread_kill_other_threads_np, pthread_kill_other_threads_np) + +/* Concurrency symbol level. */ +static int current_level; + +int __pthread_setconcurrency(int level) +{ + /* We don't do anything unless we have found a useful interpretation. */ + current_level = level; + return 0; +} +weak_alias (__pthread_setconcurrency, pthread_setconcurrency) + +int __pthread_getconcurrency(void) +{ + return current_level; +} +weak_alias (__pthread_getconcurrency, pthread_getconcurrency) + +void __pthread_set_own_extricate_if(pthread_descr self, pthread_extricate_if *peif) +{ + __pthread_lock(self->p_lock, self); + THREAD_SETMEM(self, p_extricate, peif); + __pthread_unlock(self->p_lock); +} + +/* Primitives for controlling thread execution */ + +void __pthread_wait_for_restart_signal(pthread_descr self) +{ + sigset_t mask; + + sigprocmask(SIG_SETMASK, NULL, &mask); /* Get current signal mask */ + sigdelset(&mask, __pthread_sig_restart); /* Unblock the restart signal */ + do { + self->p_signal = 0; + PDEBUG("temporary block mask = %x\n", mask); + sigsuspend(&mask); /* Wait for signal */ + PDEBUG(" *** after sigsuspend *** \n"); + } while (self->p_signal !=__pthread_sig_restart ); +} + +/* The _old variants are for 2.0 and early 2.1 kernels which don't have RT signals. + On these kernels, we use SIGUSR1 and SIGUSR2 for restart and cancellation. + Since the restart signal does not queue, we use an atomic counter to create + queuing semantics. This is needed to resolve a rare race condition in + pthread_cond_timedwait_relative. */ + +void __pthread_restart_old(pthread_descr th) +{ + if (atomic_increment(&th->p_resume_count) == -1) + kill(th->p_pid, __pthread_sig_restart); +} + +void __pthread_suspend_old(pthread_descr self) +{ + if (atomic_decrement(&self->p_resume_count) <= 0) + __pthread_wait_for_restart_signal(self); +} + +void __pthread_restart_new(pthread_descr th) +{ + kill(th->p_pid, __pthread_sig_restart); +} + +/* There is no __pthread_suspend_new because it would just + be a wasteful wrapper for __pthread_wait_for_restart_signal */ + +/* Debugging aid */ + +#ifdef DEBUG_PT +#include <stdarg.h> + +void __pthread_message(char * fmt, ...) +{ + char buffer[1024]; + va_list args; + sprintf(buffer, "%05d : ", __getpid()); + va_start(args, fmt); + vsnprintf(buffer + 8, sizeof(buffer) - 8, fmt, args); + va_end(args); + __libc_write(2, buffer, strlen(buffer)); +} + +#endif + + +#ifndef PIC +/* We need a hook to force the cancelation wrappers to be linked in when + static libpthread is used. */ +extern const int __pthread_provide_wrappers; +static const int *const __pthread_require_wrappers = + &__pthread_provide_wrappers; +#endif |