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nginx/src/os/unix/ngx_freebsd_rfork_thread.c
Igor Sysoev c2068d08f0 nginx-0.3.3-RELEASE import 
*) Change: the "bl" and "af" parameters of the "listen" directive was
       renamed to the "backlog" and "accept_filter".

    *) Feature: the "rcvbuf" and "sndbuf" parameters of the "listen"
       directive.

    *) Change: the "$msec" log parameter does not require now the
       additional the gettimeofday() system call.

    *) Feature: the -t switch now tests the "listen" directives.

    *) Bugfix: if the invalid address was specified in the "listen"
       directive, then after the -HUP signal nginx left an open socket in
       the CLOSED state.

    *) Bugfix: the mime type may be incorrectly set to default value for
       index file with variable in the name; the bug had appeared in 0.3.0.

    *) Feature: the "timer_resolution" directive.

    *) Feature: the millisecond "$upstream_response_time" log parameter.

    *) Bugfix: a temporary file with client request body now is removed
       just after the response header was transferred to a client.

    *) Bugfix: OpenSSL 0.9.6 compatibility.

    *) Bugfix: the SSL certificate and key file paths could not be relative.

    *) Bugfix: the "ssl_prefer_server_ciphers" directive did not work in
       the ngx_imap_ssl_module.

    *) Bugfix: the "ssl_protocols" directive allowed to specify the single
       protocol only.
2005-10-19 12:33:58 +00:00

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/*
* Copyright (C) Igor Sysoev
*/
#include <ngx_config.h>
#include <ngx_core.h>
/*
* The threads implementation uses the rfork(RFPROC|RFTHREAD|RFMEM) syscall
* to create threads. All threads use the stacks of the same size mmap()ed
* below the main stack. Thus the current thread id is determinated via
* the stack pointer value.
*
* The mutex implementation uses the ngx_atomic_cmp_set() operation
* to acquire a mutex and the SysV semaphore to wait on a mutex and to wake up
* the waiting threads. The light mutex does not use semaphore, so after
* spinning in the lock the thread calls sched_yield(). However the light
* mutecies are intended to be used with the "trylock" operation only.
* The SysV semop() is a cheap syscall, particularly if it has little sembuf's
* and does not use SEM_UNDO.
*
* The condition variable implementation uses the signal #64.
* The signal handler is SIG_IGN so the kill() is a cheap syscall.
* The thread waits a signal in kevent(). The use of the EVFILT_SIGNAL
* is safe since FreeBSD 4.10-STABLE.
*
* This threads implementation currently works on i386 (486+) and amd64
* platforms only.
*/
char *ngx_freebsd_kern_usrstack;
size_t ngx_thread_stack_size;
static size_t rz_size;
static size_t usable_stack_size;
static char *last_stack;
static ngx_uint_t nthreads;
static ngx_uint_t max_threads;
static ngx_uint_t nkeys;
static ngx_tid_t *tids; /* the threads tids array */
void **ngx_tls; /* the threads tls's array */
/* the thread-safe libc errno */
static int errno0; /* the main thread's errno */
static int *errnos; /* the threads errno's array */
int *
__error()
{
int tid;
tid = ngx_gettid();
return tid ? &errnos[tid - 1] : &errno0;
}
/*
* __isthreaded enables the spinlocks in some libc functions, i.e. in malloc()
* and some other places. Nevertheless we protect our malloc()/free() calls
* by own mutex that is more efficient than the spinlock.
*
* _spinlock() is a weak referenced stub in src/lib/libc/gen/_spinlock_stub.c
* that does nothing.
*/
extern int __isthreaded;
void
_spinlock(ngx_atomic_t *lock)
{
ngx_int_t tries;
tries = 0;
for ( ;; ) {
if (*lock) {
if (ngx_ncpu > 1 && tries++ < 1000) {
continue;
}
sched_yield();
tries = 0;
} else {
if (ngx_atomic_cmp_set(lock, 0, 1)) {
return;
}
}
}
}
/*
* Before FreeBSD 5.1 _spinunlock() is a simple #define in
* src/lib/libc/include/spinlock.h that zeroes lock.
*
* Since FreeBSD 5.1 _spinunlock() is a weak referenced stub in
* src/lib/libc/gen/_spinlock_stub.c that does nothing.
*/
#ifndef _spinunlock
void
_spinunlock(ngx_atomic_t *lock)
{
*lock = 0;
}
#endif
ngx_err_t
ngx_create_thread(ngx_tid_t *tid, ngx_thread_value_t (*func)(void *arg),
void *arg, ngx_log_t *log)
{
ngx_pid_t id;
ngx_err_t err;
char *stack, *stack_top;
if (nthreads >= max_threads) {
ngx_log_error(NGX_LOG_CRIT, log, 0,
"no more than %ui threads can be created", max_threads);
return NGX_ERROR;
}
last_stack -= ngx_thread_stack_size;
stack = mmap(last_stack, usable_stack_size, PROT_READ|PROT_WRITE,
MAP_STACK, -1, 0);
if (stack == MAP_FAILED) {
ngx_log_error(NGX_LOG_ALERT, log, ngx_errno,
"mmap(%p:%uz, MAP_STACK) thread stack failed",
last_stack, usable_stack_size);
return NGX_ERROR;
}
if (stack != last_stack) {
ngx_log_error(NGX_LOG_ALERT, log, 0,
"stack %p address was changed to %p", last_stack, stack);
return NGX_ERROR;
}
stack_top = stack + usable_stack_size;
ngx_log_debug2(NGX_LOG_DEBUG_CORE, log, 0,
"thread stack: %p-%p", stack, stack_top);
ngx_set_errno(0);
id = rfork_thread(RFPROC|RFTHREAD|RFMEM, stack_top,
(ngx_rfork_thread_func_pt) func, arg);
err = ngx_errno;
if (id == -1) {
ngx_log_error(NGX_LOG_ALERT, log, err, "rfork() failed");
} else {
*tid = id;
nthreads = (ngx_freebsd_kern_usrstack - stack_top)
/ ngx_thread_stack_size;
tids[nthreads] = id;
ngx_log_debug1(NGX_LOG_DEBUG_CORE, log, 0, "rfork()ed thread: %P", id);
}
return err;
}
ngx_int_t
ngx_init_threads(int n, size_t size, ngx_cycle_t *cycle)
{
char *red_zone, *zone;
size_t len;
ngx_int_t i;
struct sigaction sa;
max_threads = n + 1;
for (i = 0; i < n; i++) {
ngx_memzero(&sa, sizeof(struct sigaction));
sa.sa_handler = SIG_IGN;
sigemptyset(&sa.sa_mask);
if (sigaction(NGX_CV_SIGNAL, &sa, NULL) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"sigaction(%d, SIG_IGN) failed", NGX_CV_SIGNAL);
return NGX_ERROR;
}
}
len = sizeof(ngx_freebsd_kern_usrstack);
if (sysctlbyname("kern.usrstack", &ngx_freebsd_kern_usrstack, &len,
NULL, 0) == -1)
{
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"sysctlbyname(kern.usrstack) failed");
return NGX_ERROR;
}
/* the main thread stack red zone */
rz_size = ngx_pagesize;
red_zone = ngx_freebsd_kern_usrstack - (size + rz_size);
ngx_log_debug2(NGX_LOG_DEBUG_CORE, cycle->log, 0,
"usrstack: %p red zone: %p",
ngx_freebsd_kern_usrstack, red_zone);
zone = mmap(red_zone, rz_size, PROT_NONE, MAP_ANON, -1, 0);
if (zone == MAP_FAILED) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"mmap(%p:%uz, PROT_NONE, MAP_ANON) red zone failed",
red_zone, rz_size);
return NGX_ERROR;
}
if (zone != red_zone) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, 0,
"red zone %p address was changed to %p", red_zone, zone);
return NGX_ERROR;
}
/* create the thread errno' array */
errnos = ngx_calloc(n * sizeof(int), cycle->log);
if (errnos == NULL) {
return NGX_ERROR;
}
/* create the thread tids array */
tids = ngx_calloc((n + 1) * sizeof(ngx_tid_t), cycle->log);
if (tids == NULL) {
return NGX_ERROR;
}
tids[0] = ngx_pid;
/* create the thread tls' array */
ngx_tls = ngx_calloc(NGX_THREAD_KEYS_MAX * (n + 1) * sizeof(void *),
cycle->log);
if (ngx_tls == NULL) {
return NGX_ERROR;
}
nthreads = 1;
last_stack = zone + rz_size;
usable_stack_size = size;
ngx_thread_stack_size = size + rz_size;
/* allow the spinlock in libc malloc() */
__isthreaded = 1;
ngx_threaded = 1;
return NGX_OK;
}
ngx_tid_t
ngx_thread_self()
{
ngx_int_t tid;
tid = ngx_gettid();
if (tids == NULL) {
return ngx_pid;
}
return tids[tid];
}
ngx_err_t
ngx_thread_key_create(ngx_tls_key_t *key)
{
if (nkeys >= NGX_THREAD_KEYS_MAX) {
return NGX_ENOMEM;
}
*key = nkeys++;
return 0;
}
ngx_err_t
ngx_thread_set_tls(ngx_tls_key_t key, void *value)
{
if (key >= NGX_THREAD_KEYS_MAX) {
return NGX_EINVAL;
}
ngx_tls[key * NGX_THREAD_KEYS_MAX + ngx_gettid()] = value;
return 0;
}
ngx_mutex_t *
ngx_mutex_init(ngx_log_t *log, ngx_uint_t flags)
{
ngx_mutex_t *m;
union semun op;
m = ngx_alloc(sizeof(ngx_mutex_t), log);
if (m == NULL) {
return NULL;
}
m->lock = 0;
m->log = log;
if (flags & NGX_MUTEX_LIGHT) {
m->semid = -1;
return m;
}
m->semid = semget(IPC_PRIVATE, 1, SEM_R|SEM_A);
if (m->semid == -1) {
ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, "semget() failed");
return NULL;
}
op.val = 0;
if (semctl(m->semid, 0, SETVAL, op) == -1) {
ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, "semctl(SETVAL) failed");
if (semctl(m->semid, 0, IPC_RMID) == -1) {
ngx_log_error(NGX_LOG_ALERT, log, ngx_errno,
"semctl(IPC_RMID) failed");
}
return NULL;
}
return m;
}
void
ngx_mutex_destroy(ngx_mutex_t *m)
{
if (semctl(m->semid, 0, IPC_RMID) == -1) {
ngx_log_error(NGX_LOG_ALERT, m->log, ngx_errno,
"semctl(IPC_RMID) failed");
}
ngx_free((void *) m);
}
ngx_int_t
ngx_mutex_dolock(ngx_mutex_t *m, ngx_int_t try)
{
uint32_t lock, old;
ngx_uint_t tries;
struct sembuf op;
if (!ngx_threaded) {
return NGX_OK;
}
#if (NGX_DEBUG)
if (try) {
ngx_log_debug2(NGX_LOG_DEBUG_MUTEX, m->log, 0,
"try lock mutex %p lock:%XD", m, m->lock);
} else {
ngx_log_debug2(NGX_LOG_DEBUG_MUTEX, m->log, 0,
"lock mutex %p lock:%XD", m, m->lock);
}
#endif
old = m->lock;
tries = 0;
for ( ;; ) {
if (old & NGX_MUTEX_LOCK_BUSY) {
if (try) {
return NGX_AGAIN;
}
if (ngx_ncpu > 1 && tries++ < 1000) {
/* the spinlock is used only on the SMP system */
old = m->lock;
continue;
}
if (m->semid == -1) {
sched_yield();
tries = 0;
old = m->lock;
continue;
}
ngx_log_debug2(NGX_LOG_DEBUG_MUTEX, m->log, 0,
"mutex %p lock:%XD", m, m->lock);
/*
* The mutex is locked so we increase a number
* of the threads that are waiting on the mutex
*/
lock = old + 1;
if ((lock & ~NGX_MUTEX_LOCK_BUSY) > nthreads) {
ngx_log_error(NGX_LOG_ALERT, m->log, ngx_errno,
"%D threads wait for mutex %p, "
"while only %ui threads are available",
lock & ~NGX_MUTEX_LOCK_BUSY, m, nthreads);
ngx_abort();
}
if (ngx_atomic_cmp_set(&m->lock, old, lock)) {
ngx_log_debug2(NGX_LOG_DEBUG_MUTEX, m->log, 0,
"wait mutex %p lock:%XD", m, m->lock);
/*
* The number of the waiting threads has been increased
* and we would wait on the SysV semaphore.
* A semaphore should wake up us more efficiently than
* a simple sched_yield() or usleep().
*/
op.sem_num = 0;
op.sem_op = -1;
op.sem_flg = 0;
if (semop(m->semid, &op, 1) == -1) {
ngx_log_error(NGX_LOG_ALERT, m->log, ngx_errno,
"semop() failed while waiting on mutex %p", m);
ngx_abort();
}
ngx_log_debug2(NGX_LOG_DEBUG_MUTEX, m->log, 0,
"mutex waked up %p lock:%XD", m, m->lock);
tries = 0;
old = m->lock;
continue;
}
old = m->lock;
} else {
lock = old | NGX_MUTEX_LOCK_BUSY;
if (ngx_atomic_cmp_set(&m->lock, old, lock)) {
/* we locked the mutex */
break;
}
old = m->lock;
}
if (tries++ > 1000) {
ngx_log_debug1(NGX_LOG_DEBUG_MUTEX, m->log, 0,
"mutex %p is contested", m);
/* the mutex is probably contested so we are giving up now */
sched_yield();
tries = 0;
old = m->lock;
}
}
ngx_log_debug2(NGX_LOG_DEBUG_MUTEX, m->log, 0,
"mutex %p is locked, lock:%XD", m, m->lock);
return NGX_OK;
}
void
ngx_mutex_unlock(ngx_mutex_t *m)
{
uint32_t lock, old;
struct sembuf op;
if (!ngx_threaded) {
return;
}
old = m->lock;
if (!(old & NGX_MUTEX_LOCK_BUSY)) {
ngx_log_error(NGX_LOG_ALERT, m->log, 0,
"trying to unlock the free mutex %p", m);
ngx_abort();
}
/* free the mutex */
#if 0
ngx_log_debug2(NGX_LOG_DEBUG_MUTEX, m->log, 0,
"unlock mutex %p lock:%XD", m, old);
#endif
for ( ;; ) {
lock = old & ~NGX_MUTEX_LOCK_BUSY;
if (ngx_atomic_cmp_set(&m->lock, old, lock)) {
break;
}
old = m->lock;
}
if (m->semid == -1) {
ngx_log_debug1(NGX_LOG_DEBUG_MUTEX, m->log, 0,
"mutex %p is unlocked", m);
return;
}
/* check whether we need to wake up a waiting thread */
old = m->lock;
for ( ;; ) {
if (old & NGX_MUTEX_LOCK_BUSY) {
/* the mutex is just locked by another thread */
break;
}
if (old == 0) {
break;
}
/* there are the waiting threads */
lock = old - 1;
if (ngx_atomic_cmp_set(&m->lock, old, lock)) {
/* wake up the thread that waits on semaphore */
ngx_log_debug1(NGX_LOG_DEBUG_MUTEX, m->log, 0,
"wake up mutex %p", m);
op.sem_num = 0;
op.sem_op = 1;
op.sem_flg = 0;
if (semop(m->semid, &op, 1) == -1) {
ngx_log_error(NGX_LOG_ALERT, m->log, ngx_errno,
"semop() failed while waking up on mutex %p", m);
ngx_abort();
}
break;
}
old = m->lock;
}
ngx_log_debug1(NGX_LOG_DEBUG_MUTEX, m->log, 0,
"mutex %p is unlocked", m);
return;
}
ngx_cond_t *
ngx_cond_init(ngx_log_t *log)
{
ngx_cond_t *cv;
cv = ngx_alloc(sizeof(ngx_cond_t), log);
if (cv == NULL) {
return NULL;
}
cv->signo = NGX_CV_SIGNAL;
cv->tid = -1;
cv->log = log;
cv->kq = -1;
return cv;
}
void
ngx_cond_destroy(ngx_cond_t *cv)
{
if (close(cv->kq) == -1) {
ngx_log_error(NGX_LOG_ALERT, cv->log, ngx_errno,
"kqueue close() failed");
}
ngx_free(cv);
}
ngx_int_t
ngx_cond_wait(ngx_cond_t *cv, ngx_mutex_t *m)
{
int n;
ngx_err_t err;
struct kevent kev;
struct timespec ts;
if (cv->kq == -1) {
/*
* We have to add the EVFILT_SIGNAL filter in the rfork()ed thread.
* Otherwise the thread would not get a signal event.
*
* However, we have not to open the kqueue in the thread,
* it is simply handy do it together.
*/
cv->kq = kqueue();
if (cv->kq == -1) {
ngx_log_error(NGX_LOG_ALERT, cv->log, ngx_errno, "kqueue() failed");
return NGX_ERROR;
}
ngx_log_debug2(NGX_LOG_DEBUG_CORE, cv->log, 0,
"cv kq:%d signo:%d", cv->kq, cv->signo);
kev.ident = cv->signo;
kev.filter = EVFILT_SIGNAL;
kev.flags = EV_ADD;
kev.fflags = 0;
kev.data = 0;
kev.udata = NULL;
ts.tv_sec = 0;
ts.tv_nsec = 0;
if (kevent(cv->kq, &kev, 1, NULL, 0, &ts) == -1) {
ngx_log_error(NGX_LOG_ALERT, cv->log, ngx_errno, "kevent() failed");
return NGX_ERROR;
}
cv->tid = ngx_thread_self();
}
ngx_mutex_unlock(m);
ngx_log_debug3(NGX_LOG_DEBUG_CORE, cv->log, 0,
"cv %p wait, kq:%d, signo:%d", cv, cv->kq, cv->signo);
for ( ;; ) {
n = kevent(cv->kq, NULL, 0, &kev, 1, NULL);
ngx_log_debug2(NGX_LOG_DEBUG_CORE, cv->log, 0,
"cv %p kevent: %d", cv, n);
if (n == -1) {
err = ngx_errno;
ngx_log_error((err == NGX_EINTR) ? NGX_LOG_INFO : NGX_LOG_ALERT,
cv->log, ngx_errno,
"kevent() failed while waiting condition variable %p",
cv);
if (err == NGX_EINTR) {
break;
}
return NGX_ERROR;
}
if (n == 0) {
ngx_log_error(NGX_LOG_ALERT, cv->log, 0,
"kevent() returned no events "
"while waiting condition variable %p",
cv);
continue;
}
if (kev.filter != EVFILT_SIGNAL) {
ngx_log_error(NGX_LOG_ALERT, cv->log, 0,
"kevent() returned unexpected events: %d "
"while waiting condition variable %p",
kev.filter, cv);
continue;
}
if (kev.ident != (uintptr_t) cv->signo) {
ngx_log_error(NGX_LOG_ALERT, cv->log, 0,
"kevent() returned unexpected signal: %d ",
"while waiting condition variable %p",
kev.ident, cv);
continue;
}
break;
}
ngx_log_debug1(NGX_LOG_DEBUG_CORE, cv->log, 0, "cv %p is waked up", cv);
ngx_mutex_lock(m);
return NGX_OK;
}
ngx_int_t
ngx_cond_signal(ngx_cond_t *cv)
{
ngx_err_t err;
ngx_log_debug3(NGX_LOG_DEBUG_CORE, cv->log, 0,
"cv %p to signal %P %d",
cv, cv->tid, cv->signo);
if (cv->tid == -1) {
return NGX_OK;
}
if (kill(cv->tid, cv->signo) == -1) {
err = ngx_errno;
ngx_log_error(NGX_LOG_ALERT, cv->log, err,
"kill() failed while signaling condition variable %p", cv);
if (err == NGX_ESRCH) {
cv->tid = -1;
}
return NGX_ERROR;
}
ngx_log_debug1(NGX_LOG_DEBUG_CORE, cv->log, 0, "cv %p is signaled", cv);
return NGX_OK;
}
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