diff options
Diffstat (limited to 'app/nginx/src/core/ngx_shmtx.c')
| -rw-r--r-- | app/nginx/src/core/ngx_shmtx.c | 310 |
1 files changed, 310 insertions, 0 deletions
diff --git a/app/nginx/src/core/ngx_shmtx.c b/app/nginx/src/core/ngx_shmtx.c new file mode 100644 index 0000000..a255903 --- /dev/null +++ b/app/nginx/src/core/ngx_shmtx.c @@ -0,0 +1,310 @@ + +/* + * Copyright (C) Igor Sysoev + * Copyright (C) Nginx, Inc. + */ + + +#include <ngx_config.h> +#include <ngx_core.h> + + +#if (NGX_HAVE_ATOMIC_OPS) + + +static void ngx_shmtx_wakeup(ngx_shmtx_t *mtx); + + +ngx_int_t +ngx_shmtx_create(ngx_shmtx_t *mtx, ngx_shmtx_sh_t *addr, u_char *name) +{ + mtx->lock = &addr->lock; + + if (mtx->spin == (ngx_uint_t) -1) { + return NGX_OK; + } + + mtx->spin = 2048; + +#if (NGX_HAVE_POSIX_SEM) + + mtx->wait = &addr->wait; + + if (sem_init(&mtx->sem, 1, 0) == -1) { + ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_errno, + "sem_init() failed"); + } else { + mtx->semaphore = 1; + } + +#endif + + return NGX_OK; +} + + +void +ngx_shmtx_destroy(ngx_shmtx_t *mtx) +{ +#if (NGX_HAVE_POSIX_SEM) + + if (mtx->semaphore) { + if (sem_destroy(&mtx->sem) == -1) { + ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_errno, + "sem_destroy() failed"); + } + } + +#endif +} + + +ngx_uint_t +ngx_shmtx_trylock(ngx_shmtx_t *mtx) +{ + return (*mtx->lock == 0 && ngx_atomic_cmp_set(mtx->lock, 0, ngx_pid)); +} + + +void +ngx_shmtx_lock(ngx_shmtx_t *mtx) +{ + ngx_uint_t i, n; + + ngx_log_debug0(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, "shmtx lock"); + + for ( ;; ) { + + if (*mtx->lock == 0 && ngx_atomic_cmp_set(mtx->lock, 0, ngx_pid)) { + return; + } + + if (ngx_ncpu > 1) { + + for (n = 1; n < mtx->spin; n <<= 1) { + + for (i = 0; i < n; i++) { + ngx_cpu_pause(); + } + + if (*mtx->lock == 0 + && ngx_atomic_cmp_set(mtx->lock, 0, ngx_pid)) + { + return; + } + } + } + +#if (NGX_HAVE_POSIX_SEM) + + if (mtx->semaphore) { + (void) ngx_atomic_fetch_add(mtx->wait, 1); + + if (*mtx->lock == 0 && ngx_atomic_cmp_set(mtx->lock, 0, ngx_pid)) { + (void) ngx_atomic_fetch_add(mtx->wait, -1); + return; + } + + ngx_log_debug1(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, + "shmtx wait %uA", *mtx->wait); + + while (sem_wait(&mtx->sem) == -1) { + ngx_err_t err; + + err = ngx_errno; + + if (err != NGX_EINTR) { + ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, err, + "sem_wait() failed while waiting on shmtx"); + break; + } + } + + ngx_log_debug0(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, + "shmtx awoke"); + + continue; + } + +#endif + + ngx_sched_yield(); + } +} + + +void +ngx_shmtx_unlock(ngx_shmtx_t *mtx) +{ + if (mtx->spin != (ngx_uint_t) -1) { + ngx_log_debug0(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, "shmtx unlock"); + } + + if (ngx_atomic_cmp_set(mtx->lock, ngx_pid, 0)) { + ngx_shmtx_wakeup(mtx); + } +} + + +ngx_uint_t +ngx_shmtx_force_unlock(ngx_shmtx_t *mtx, ngx_pid_t pid) +{ + ngx_log_debug0(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, + "shmtx forced unlock"); + + if (ngx_atomic_cmp_set(mtx->lock, pid, 0)) { + ngx_shmtx_wakeup(mtx); + return 1; + } + + return 0; +} + + +static void +ngx_shmtx_wakeup(ngx_shmtx_t *mtx) +{ +#if (NGX_HAVE_POSIX_SEM) + ngx_atomic_uint_t wait; + + if (!mtx->semaphore) { + return; + } + + for ( ;; ) { + + wait = *mtx->wait; + + if ((ngx_atomic_int_t) wait <= 0) { + return; + } + + if (ngx_atomic_cmp_set(mtx->wait, wait, wait - 1)) { + break; + } + } + + ngx_log_debug1(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, + "shmtx wake %uA", wait); + + if (sem_post(&mtx->sem) == -1) { + ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_errno, + "sem_post() failed while wake shmtx"); + } + +#endif +} + + +#else + + +ngx_int_t +ngx_shmtx_create(ngx_shmtx_t *mtx, ngx_shmtx_sh_t *addr, u_char *name) +{ + if (mtx->name) { + + if (ngx_strcmp(name, mtx->name) == 0) { + mtx->name = name; + return NGX_OK; + } + + ngx_shmtx_destroy(mtx); + } + + mtx->fd = ngx_open_file(name, NGX_FILE_RDWR, NGX_FILE_CREATE_OR_OPEN, + NGX_FILE_DEFAULT_ACCESS); + + if (mtx->fd == NGX_INVALID_FILE) { + ngx_log_error(NGX_LOG_EMERG, ngx_cycle->log, ngx_errno, + ngx_open_file_n " \"%s\" failed", name); + return NGX_ERROR; + } + + if (ngx_delete_file(name) == NGX_FILE_ERROR) { + ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_errno, + ngx_delete_file_n " \"%s\" failed", name); + } + + mtx->name = name; + + return NGX_OK; +} + + +void +ngx_shmtx_destroy(ngx_shmtx_t *mtx) +{ + if (ngx_close_file(mtx->fd) == NGX_FILE_ERROR) { + ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_errno, + ngx_close_file_n " \"%s\" failed", mtx->name); + } +} + + +ngx_uint_t +ngx_shmtx_trylock(ngx_shmtx_t *mtx) +{ + ngx_err_t err; + + err = ngx_trylock_fd(mtx->fd); + + if (err == 0) { + return 1; + } + + if (err == NGX_EAGAIN) { + return 0; + } + +#if __osf__ /* Tru64 UNIX */ + + if (err == NGX_EACCES) { + return 0; + } + +#endif + + ngx_log_abort(err, ngx_trylock_fd_n " %s failed", mtx->name); + + return 0; +} + + +void +ngx_shmtx_lock(ngx_shmtx_t *mtx) +{ + ngx_err_t err; + + err = ngx_lock_fd(mtx->fd); + + if (err == 0) { + return; + } + + ngx_log_abort(err, ngx_lock_fd_n " %s failed", mtx->name); +} + + +void +ngx_shmtx_unlock(ngx_shmtx_t *mtx) +{ + ngx_err_t err; + + err = ngx_unlock_fd(mtx->fd); + + if (err == 0) { + return; + } + + ngx_log_abort(err, ngx_unlock_fd_n " %s failed", mtx->name); +} + + +ngx_uint_t +ngx_shmtx_force_unlock(ngx_shmtx_t *mtx, ngx_pid_t pid) +{ + return 0; +} + +#endif |